Lactobacillus

J Bacteriol, 1998 Aug, 180(15), 4011 - 4
Functional expression in Lactobacillus plantarum of xylP encoding the isoprimeverose transporter of Lactobacillus pentosus; Chaillou S et al.; The xylP gene of Lactobacillus pentosus, the first gene of the xylPQR operon, was recently found to be involved in isoprimeverose metabolism . By expression of xylP on a multicopy plasmid in Lactobacillus plantarum 80, a strain which lacks active isoprimeverose and D-xylose transport activities, it was shown that xylP encodes a transporter . Functional expression of the XylP transporter was shown by uptake of isoprimeverose in L . plantarum 80 cells, and this transport was driven by the proton motive force generated by malolactic fermentation . XylP was unable to catalyze transport of D-xylose.

Eur J Clin Nutr, 1998 Jun, 52(6), 436 - 40
Effects of a milk product, fermented by Lactobacillus acidophilus and with fructo-oligosaccharides added, on blood lipids in male volunteers; Schaafsma G et al.; OBJECTIVE: To investigate in adult male volunteers the effect of a new fermented milk product, fermented by Lactobacillus acidophilus and with fructo-oligosaccharides added, on blood lipids . DESIGN: Randomized placebo-controlled double-blind two-way cross over trial with two treatment periods of three weeks, separated by a wash-out period of one week . SETTING: the study was performed at the TNO Nutrition and Food Research Institute in Zeist, The Netherlands . SUBECTS: Thirty normal healthy men, aged 33-64y (mean serum total cholesterol level: 5.23 +/- 1.03 (s.d.)), were selected for this study . Normal health was assessed by pre study screening . All subjects were used to an average Dutch food pattern . INTERVENTIONS: During the treatment periods subjects consumed three times daily a 125 ml of either test or reference product as a part of their habitual diet . The test product was a milk, fermented by yogurt starters and Lactobacillus acidophilus, and contained 2.5% fructo-oligosaccharides, 0.5% vegetable oil and 0.5% milk fat . The reference product was a traditional yogurt (milk fermented only by yogurt strains), containing 1% milk fat . Blood samples for serum lipid analysis and blood glucose measurements were taken before the start of the experiment and at the end of both treatment periods . RESULTS: As compared to the reference product, consumption of the test product resulted in significantly lower values for serum total cholesterol (P < 0.001), LDL-cholesterol (P < 0.005), and the LDL/HDL-ratio (P < 0.05) by 4.4, 5.4 and 5.3% respectively . Levels of serum HDL-cholesterol, triglycerides and blood glucose remained essentially unchanged . The beneficial effects of the test product on serum cholesterol were largely related to an increase of this parameter during the consumption of the reference product . CONCLUSIONS: As compared to traditional yogurt, daily consumption of three times 125 ml of test product specifically lowered serum LDL-cholesterol levels in normal healthy male adult subjects with borderline elevated levels of serum total cholesterol within three weeks.

Oral Dis, 1998 Jun, 4(2), 114 - 9
Accumulation of strontium and fluoride in approximal dental plaque and changes in plaque microflora after rinsing with chlorhexidine-fluoride-strontium solution; Spets-Happonen S et al.; OBJECTIVES: To find out if strontium is incorporated into plaque and enamel in vivo during a 2-week rinsing period with a chlorhexidine-fluoride-strontium solution and to determine the effects of the rinsing on the numbers of mutans streptococci and lactobacilli in plaque . SUBJECTS AND METHODS: A total of 18 adult participants rinsed their mouths twice a day for 2 weeks, first with a placebo solution and subsequently, separated by a 1-week interval without rinsing, with a chlorhexidine gluconate (0.05%)-sodium fluoride (0.04%)-strontium (100 ppm as SrCl2) rinsing solution (CXFSr) for another 2 weeks . RESULTS: After the CXFSr rinsing period the strontium and fluoride contents (microgram g-1 plaque dry weight; mean +/- sr) of approximal plaque were 32.5 +/- 4.7 and 72.8 +/- 9.0, compared with the respective contents of 8.4 +/- 1.2 and 42.0 +/- 4.8 after placebo rinsing (P = 0.0001 for both comparisons) . The strontium content remained elevated for 6 weeks . The median proportion of mutans streptococci of approximal plaque of the total viable count of bacteria was 1% after placebo rinsing but decreased to 0.2% after CXFSr rinsing . The proportion of mutans streptococci remained low at 3 weeks (P = 0.018 vs placebo) but had reached the placebo level at 6 weeks . Rinsing with CXFSr solution did not reduce lactobacilli in plaque . The strontium or fluoride contents of the enamel surfaces subjected to tooth brushing did not significantly change . CONCLUSIONS: Strontium and fluoride accumulated in dental plaque during a 2-week CXFSr rinsing period and the proportion of mutans streptococci in approximal plaque was reduced at least for 3 weeks after completion of the rinsing.

J Allergy Clin Immunol, 1998 Jul, 102(1), 57 - 64
Heat-killed Lactobacillus plantarum L-137 suppresses naturally fed antigen-specific IgE production by stimulation of IL-12 production in mice; Murosaki S et al.; BACKGROUND: Food allergy is caused by production of IgE against dietary antigen induced by T(H2) response . IL-12 inhibits T(H2) responses and strongly suppresses IgE production . We have recently established a murine model for IgE production with a predominant T(H2) response induced by feeding antigen . OBJECTIVE: We here show a suppressive effect of heat-killed Lactobacillus plantarum L-137, a potent inducer of IL-12, on IgE production against naturally fed antigen in a murine model . METHODS: The ability of L . plantarum L-137 to induce IL-12 production was examined in vitro and in vivo . DBA/2 mice were fed a casein diet and injected intraperitoneally with L . plantarum L-137 from the beginning of feeding or 2 weeks later . Recombinant mouse IL-12 was also injected 2 weeks after the start of feeding . Casein-specific IgE and IgG1 in plasma were determined by ELISA . RESULTS: L . plantarum L-137 directly induced IL-12 production by the peritoneal macrophages and also stimulated spleen cells to produce both IL-12 and interferon-gamma in vitro . In vivo treatment of L . plantarum L-137 also increased the plasma level of IL-12 in mice . Plasma anti-casein IgG1 and IgE levels were gradually elevated in DBA/2 mice fed a casein diet . Administration of L . plantarum L-137 from the beginning of feeding suppressed the elevation of anti-casein IgE levels, whereas the levels of anti-casein IgG1 were rather augmented by L . plantarum L-137 . IL-12 production of the peritoneal macrophages was enhanced, but IL-4 production of concanavalin A (Con A)-stimulated spleen cells was suppressed in the L . plantarum L-137-treated mice compared with control mice fed a casein diet . When L . plantarum L-137 was given from 2 weeks after the start of feeding, anti-casein IgE levels were also significantly suppressed, which was similar to the result found in mice treated with IL-12 . CONCLUSION: Our results suggest that L . plantarum L-137, a potent IL-12 inducer, is useful for prevention and treatment of food allergy.

Cryobiology, 1998 Jun, 36(4), 315 - 9
Survival Rate and Enzyme Activities of Lactobacillus acidophilus Following Frozen Storage; Fernandez Murga ML et al.; The ability of two strains of Lactobacillus acidophilus, CRL 640 and CRL 800, to survive and retain their biological activities under frozen storage was determined . Freezing and thawing, as well as frozen storage, damaged the cell membrane, rendering the microorganisms sensitive to sodium chloride and bile salts . Both lactic acid production and proteolytic activity were depressed after 21 days at -20 degreesC, whereas beta-galactosidase activity per cell unit was increased . Cell injury was partially overcome after repair in a salt-rich medium .

AIDS, 1998 Jul 9, 12(10), 1129 - 38
Preclinical studies on thiocarboxanilide UC-781 as a virucidal agent; Balzarini J et al.; BACKGROUND: Thiocarboxanilide UC-781 is a highly potent and selective non-nucleoside reverse transcriptase inhibitor (NNRTI) of HIV-1, which also has virucidal properties . Recent studies have shown that UC-781 would seem an ideal candidate for application as a vaginal virucide . OBJECTIVE: To investigate the antiviral potency and stability of UC-781 in a lipophilic gel formulation . METHODS: UC-781 was formulated in replens gel at different concentrations and administered intravaginally to rabbits at 5% in replens gel for 10 days . UC-781 was also exposed to temperatures of 4, 37 and 50 degrees C, and to low pH (6.0, 4.3, 2.0 and 1.2) . A number of microorganisms were exposed in culture to serial dilutions of UC-781 . RESULTS: The drug was stable under low pH conditions and did not lose its antiviral potency upon 4 h exposure to pH 3.5 (the estimated vaginal pH) . UC-781 can be easily formulated into a lipophilic gel (replens; up to 5%) and proved fully stable at 50 degrees C for 30 days . There was no effect on the growth of microorganisms (i.e., Candida and Lactobacillus strains) that are present in the vaginal flora . Neither systemic side-effects, nor local inflammation or damage of the vaginal mucosa or epithelium were observed in rabbits to which 5% UC-781 in replens gel had been administered . UC-781, formulated as 0.5, 0.2 and 0.05% replens gel, and UC-38, alpha-APA and zidovudine, formulated as 0.5 or 0.2% replens gel, were effective in protecting CEM cells in the very beginning against productive HIV-1 replication . This points to an efficient diffusion of the drugs from the lipophilic gel to the hydrophilic culture medium . However, subsequent subcultivations at a dilution rate of 1:10 every 3-4 days resulted in a rapid breakthrough of virus with all drugs except UC-781 in its 0.5 and 0.2% gel formulation . These cultures were fully protected against HIV-1 and remained completely cleared from virus for at least 10 subcultivations . CONCLUSIONS: The virus that emerged under 0.05% UC-781 remained highly sensitive to the NNRTI, including UC-781, in cell culture, suggesting a lack of resistance development under our experimental conditions.

J Appl Microbiol, 1998 May, 84(5), 698 - 702
Lactobacillus kunkeei sp . nov.: a spoilage organism associated with grape juice fermentations; Edwards CG et al.; A Gram-positive rod was isolated from a commercial grape wine undergoing a sluggish/stuck alcoholic fermentation . The organism produced L-lactic acid from glucose, possessed weak catalase activity, and fermented relatively few carbohydrates, i.e . glucose, fructose, sucrose, raffinose (weakly) and mannitol . The 16S rRNA gene sequence analysis revealed that the isolate was phylogenetically a member of the genus Lactobacillus and formed a distinct subline within the Lact . casei cluster of species . Based on phenotypic and phylogenetic evidence, a new species is proposed, Lact . kunkeei . The type strain of Lact . kunkeei is ATCC 700308.

Community Dent Oral Epidemiol, 1998 Jun, 26(3), 170 - 6
Factors associated with caries incidence in an elderly population; Powell LV et al.; The purpose of this paper was to identify baseline factors associated with future caries development in older adults (age 60+) during a 3-year study period . Poisson regression analysis was used to determine the association between potential risk factors and disease incidence . The significant factors associated with high coronal caries incidence rates were high baseline root DMFS (P<0.001), high counts of mutans streptococci and lactobacilli (P=0.036), male gender (P=0.007), and Asian ethnicity (P=0.002) . These factors had small to moderate effects on incidence rates, with relative risk values of approximately 1.2 to 2 . The significant factors associated with higher disease incidence on root surfaces were baseline coronal DMFS (marginally significant, P=0.078), high bacterial counts (P=0.002), and Asian ethnicity (P=0.009) . The predictive value of the models was low for both coronal and root caries . This result may be because this population had a higher than usual caries incidence rate, making discrimination among these caries-active individuals difficult . The current study affirmed the value of baseline DMFS and salivary variables to modeling caries incidence and introduced ethnicity as a variable useful for the study of dental caries in older adults.

Acta Odontol Scand, 1998 Apr, 56(2), 70 - 5
A 3-year clinical evaluation of two composite resins in class-II cavities; Rasmusson CG et al.; The purpose of this investigation was to study the clinical performance of a new system with a proposed expanding liner for composite restorations introduced in the late 1980s . The present study reports on baseline data and the result after 3 years . One hundred and four class-II cavities in 95 patients were alternatively restored by Superlux Molar and the reference material P-50 APC by 12 general practitioners in 3 public dental health clinics . After 3 years 82 restorations (79%) were available for examination . The restorations were evaluated on the basis of USPHS criteria after 1 week and again after 3 years . Stone casts were used to quantitatively categorize wear in accordance with the Leinfelder method . Color slides and bitewings were taken to supplement the clinical evaluation of color match and marginal adaptation, respectively, and secondary caries . The failure rate (USPHS rating, Charlie) was four restorations of Superlux Molar and seven of P-50 APC . The average wear after 3 years of Superlux Molar was 131 microm and of P-50 APC, 128 microm . There were no statistically significant differences between the two materials with regard to, for example, handling characteristics, anatomic form, color match, marginal discoloration, or failures . A significantly higher wear rate was found after 3 years in patients with a high level of salivary lactobacilli (> 10(5) colony-forming units (CFU)/mL at base line) compared with those with lower levels . This suggests that an acidic environment might enhance the wear rate.

Acta Odontol Scand, 1998 Apr, 56(2), 65 - 9
Betaine-containing toothpaste relieves subjective symptoms of dry mouth; Soderling E et al.; Subjects with dry mouth often experience irritation of the oral mucosa when using sodium lauryl sulfate containing products for oral hygiene . Betaine, or trimethylglycine, reduces skin-irritating effects of ingredients of cosmetics such as sodium lauryl sulfate . The aim of the present study was to compare the effects of a betaine-containing toothpaste with a regular toothpaste on the oral microbial flora, the condition of the oral mucosa, and subjective symptoms of dry mouth in subjects with chronic dry mouth symptoms . Thirteen subjects with chronic dry mouth symptoms and with a paraffin-stimulated salivary flow rate < or = 1 mL/min participated in the double-blind crossover study . Ten subjects had a very low salivary flow rate (< or = 0.6 mL/min) . The subjects used both experimental toothpastes (with or without 4% betaine) twice a day for 2 weeks . Oral examinations and microbiologic sample collections were made at the base lines preceding the two experimental periods and at the end . Standardized questions on subjective symptoms of dry mouth were used when the subjects were interviewed at the end of the two experimental periods . No study-induced significant changes were observed in the microbiologic variables (plaque index, mutans streptococci, lactobacilli, Candida species) or in the appearance of the oral mucosa . The use of the betaine-containing toothpaste was, however, associated with a significant relief of several subjective symptoms of dry mouth . Betaine appears thus to be a promising ingredient of toothpastes in general and especially of toothpastes designed for patients with dry mouth.

Eur J Clin Microbiol Infect Dis, 1998 Mar, 17(3), 203 - 5
Use of 16S rRNA gene sequencing to identify Lactobacillus casei in septicaemia secondary to a paraprosthetic enteric fistula; Parola P et al.; Human infections caused by Lactobacillus spp . are rarely reported in the literature . Underlying conditions are frequently reported, and identification of lactobacilli to the species level remains rare . A case of Lactobacillus casei septicaemia secondary to a vascular graft infection is reported . The 16S rRNA sequencing technique was used to definitively identify Lactobacillus casei.

Zh Mikrobiol Epidemiol Immunobiol, 1998 Mar-Apr, (2), 102 - 4
{Development of methods for the stabilization of biomass in the preparation of medicinal forms of lactobacterin}; Neschisliaev VA et al.; In this work the problems of obtaining medicinal forms of lactobacterin with the use of nontraditional methods for the stabilization of biomass are considered . The data on the stability of tablets, suppositories and microgranules of the preparation prepared on the basis of immobilized cells, are presented.

Carbohydr Res, 1998 Feb, 307(1-2), 125 - 33
Structural analysis of the exopolysaccharides produced by Lactobacillus spp . G-77; Duenas-Chasco MT et al.; The exopolysaccharide produced by a ropy strain of Lactobacillus spp . G-77 in a semi-defined medium, was found to be a mixture of two homopolymers composed of D-Glc . The two poly-saccharides were separated and, on the basis of monosaccharide and methylation analyses, 1H, 13C, 1D and 2D NMR experiments, one of the polysaccharides was shown to be a 2-substituted-(1-3)-beta-D-glucan, identical to that described for the EPS from Pediococcus damnosus 2.6 (M.T . Duenas-Chasco, M.A . Rodriguez-Carvajal, P . Tejero-Mateo, G . Franco-Rodriguez, J . L . Espartero, A . Irastorza-Iribar, and A.M . Gil-Serrano, Carbohydr . Res., 303 (1997) 453-458), and the other polysaccharide was shown to consist of repeating units with the following structure {formula: see text}

Biochemistry, 1998 Jul 7, 37(27), 9704 - 15
Structural and enzymatic studies of a new analogue of coenzyme B12 with an alpha-adenosyl upper axial ligand; Brown KL et al.; A new analogue of coenzyme B12 (5'-deoxyadenosylcobalamin, AdoCbl), in which the configuration of the N-glycosidic bond in the Ado ligand is inverted {(alpha-ribo)AdoCbl}, has been synthesized and its crystal structure determined by X-ray diffraction {MoKalpha, lambda = 0.71073 A, monoclinic P212121, a = 16.132(12) A, b = 21 . 684(15) A, c = 27.30(3) A, 9611 independent reflections, R1 = 0 . 0708} . As suggested by molecular mechanics modeling before the structure was known, the Ado ligand lies over the southern quadrant of the molecule, as is the case for AdoCbl . The most striking feature of the structure is disorder in the orientation of the adenine (Ade) moiety relative to the ribose of the Ado ligand . This was resolved with a two-state model in which in the major (0.57 occupancy) conformer the A16(O)-A11-A9(N)-A8 dihedral angle is 1.9 degrees and the Ade is virtually perpendicular to the corrin ring; in the minor conformer, the Ade is tilted down, and this dihedral is -48.7 degrees . The Co-C and axial Co-N bond lengths and the Co-C-C bond angle are quite similar to those in AdoCbl . The corrin ring is considerably flatter than that of AdoCbl, with a fold angle of 11.7 degrees . The molecule was successfully modeled by molecular mechanics (MM), and rotation of the Ado ligand relative to the corrin gave rise to four locally minimum structures with the Ado in the southern, eastern, northern, or western quadrant, with the southern conformation as the global minimum, as is the case with AdoCbl itself . Nuclear Overhauser effects (nOe's) observed by two-dimensional (2D) NMR were incorporated as restraints in molecular dynamics (MD) and simulated annealing (SA) calculations . A MD simulation at 300 K showed that only the southern conformation is populated with the Ado ligand confined to an arc from over C15 to over C12, while the Ade ring oscillates from perpendicular to parallel to the corrin ring . Twenty-seven structures were collected by MD-SA . Most of these annealed into the southern conformation, but examples of the other conformations were also found . The new analogue is a partially active coenzyme for the ribonucleotide reductase from Lactobacillus leichmanii with maximal activity that is 9.7% of that of AdoCbl itself, and a very high Km value (245 microM compared to 0.54 microM for AdoCbl) . In addition, the rate constant for enzyme-induced carbon-cobalt bond cleavage of (alpha-ribo)AdoCbl is 160-fold smaller than that for AdoCbl, and only 1/3 as much cob(II)alamin is produced at the active site.

Food Chem Toxicol, 1998 Apr, 36(4), 321 - 6
Ability of dairy strains of lactic acid bacteria to bind a common food carcinogen, aflatoxin B1; El-Nezami H et al.; This study was conducted to examine the ability of selected dairy strains of lactic acid bacteria to remove aflatoxin B1 (AFB1) from liquid media . Both Lactobacillus rhamnosus strain GG (LBGG) and L . rhamnosus strain LC-705 (LC705) can significantly (P > 0.05) remove AFB1 when compared with that by other strains of either Gram-positive or Gram-negative bacteria . Removal of AFB1 by LBGG and LC705 was a rapid process with approximately 80% AFB1 removed at 0 hr . Removal of AFB1 by these two strains was both temperature and bacterial concentration dependent.

Biosci Biotechnol Biochem, 1998 May, 62(5), 887 - 92
Sequence analysis by cloning of the structural gene of gassericin A, a hydrophobic bacteriocin produced by Lactobacillus gasseri LA39; Kawai Y et al.; Gassericin A, a bacteriocin from Lactobacillus gasseri LA39, was purified to homogeneity from the culturesupernatant mainly by reverse-phase chromatography . The molecular weight of gassericin A was found to be 5,652 by mass analysis, unlike the estimated 3,800 found by SDS-PAGE . However, when the purified preparation was treated with lysylendopeptidase, it migrated as a single band to 5,600 with bacteriocin activity on SDS-PAGE . N- and C-terminal amino acids could not be identified . The internal amino acid could be identified after gassericin A was hydrolyzed with lysylendopeptidase . The DNA of the structural gene of gassericin A was sequenced by cloning of the gene from chromosomal DNA with an oligonucleotide probe . The structural gene of gassericin A was found on the chromosomal DNA as an open reading frame encoding a protein composed of 91 amino acids . The amino acid sequence of mature gassericin A was predicted to be 58 residues from the DNA sequence and results of mass analysis . These results suggested that gassericin A has a closed circular structure with N- and C-terminals linked . Gassericin A is a hydrophobic class II bacteriocin; it was 98% identical with acidocin B produced by Lactobacillus acidophilus M46.

Appl Environ Microbiol, 1998 Jul 1, 64(7), 2616 - 23
Modeling of Growth of Lactobacillus sanfranciscensis and Candida milleri in Response to Process Parameters of Sourdough Fermentation; Ganzle MG et al.; We investigated the effect of the ecological factors pH, temperature, ionic strength, and lactate, acetate, and ethanol levels on Candida milleri and two strains of Lactobacillus sanfranciscensis, organisms representative of the microflora of sourdough . A mathematical model describing the single and combined effects of these factors on the growth of these organisms was established in accordance with the following criteria: quality of fit, biological significance of the parameters, and applicability of the in vitro data to in situ processes . The growth rates of L . sanfranciscensis LTH1729 and LTH2581 were virtually identical under all conditions tested . These organisms tolerated >160 mmol of undissociated acetic acid per liter . Growth occurred in the pH range of 3.9 to 6.7 and was completely inhibited by 4% NaCl . C . milleri had a lower optimum temperature for growth (27 degreesC) than the lactobacilli . The growth of the yeast was not affected by pH in the range of 3.5 to 7, and up to 8% NaCl was tolerated . Complete inhibition of growth occurred at 150 mmol of undissociated acetic acid per liter, but acetate at concentrations of up to 250 mmol/liter exerted virtually no effect . The model provides insight into factors contributing to the stability of the sourdough microflora and can facilitate the design of novel sourdough processes.

Appl Environ Microbiol, 1998 Jul 1, 64(7), 2418 - 23
Differentiation of Lactobacillus Species by Molecular Typing; Zhong W et al.; A total of 64 type, reference, clinical, health food, and stock isolates of microaerophilic Lactobacillus species were examined by restriction fragment length polymorphisms . Of particular interest were members of six of the eight species most commonly recovered from the vaginas of healthy premenopausal women, namely, Lactobacillus jensenii, L . casei, L . rhamnosus, L . acidophilus, L . plantarum, and L . fermentum . Six main groupings were identified on the basis of ribotyping . This technique was able to classify fresh isolates to the species level . In the case of the ribotype A grouping for L . rhamnosus, differences between strains were evident by chromosome typing (chromotyping) . Many isolates did not possess plasmids . Six L . rhamnosus strains isolated from four different health food products appeared to be identical to L . rhamnosus ATCC 21052 . The molecular typing system is useful for identifying and differentiating Lactobacillus isolates . Studies of strains of potential importance to the urogenital flora should include molecular characterization as a means of comparing genetic traits with those of strains whose characteristics associated with colonization and antagonism against pathogens have been defined.

Dtsch Tierarztl Wochenschr, 1998 May, 105(5), 199 - 200
Colonization capability of orally administered Lactobacillus strains in the gut of gnotobiotic piglets; Nemcova R et al.; In the present study, the effect of Lactobacillus casei subsp . casei and Lactobacillus fermentum inoculation on jejunum and ileum colonization in gnotobiotic piglets has been observed . The characteristic features of the strains used were strong adherence to pig epithelial gut cells as well as inhibitory activity against enteropathogenic E . coli under in vitro conditions . Strains were inoculated to 2, 3, and 4 day old gnotobiotic piglets at a dose of 2 ml (1 x 10(8) germs/ml) . On the second day after the last inoculation, Lactobacillus casei subsp . casei strain counts adhered to the jejunum mucosa and those adhered to the ileum mucosa were 4.54 log 10.cm-2 and 5.40 log 10.cm-2, respectively . Lactobacillus fermentum counts adhered to the jejunum mucosa and those adhered to the ileum mucosa were 5.73 log 10.cm-2 and 4.01 log 10.cm-2, respectively . On day 5 after the last inoculation, the counts in both strains were by one log higher . The results obtained point out to the fact that Lactobacillus casei subsp . casei and Lactobacillus fermentum colonized the mucosa of both jejunum and ileum and survived in the intestinal tract . The adherence of lactobacilli to gut cells in vitro correlated with their capability to adhere to the mucosa of both jejunum and ileum in vivo.

J Bacteriol, 1998 Jul, 180(13), 3474 - 6
Identification of the repressor-encoding gene of the Lactobacillus bacteriophage A2; Ladero V et al.; The repressor gene of the Lactobacillus phage A2 has the following properties: it (i) encodes a 224-residue polypeptide with DNA binding and RecA cleavage motifs, (ii) is expressed in lysogenic cultures, and (iii) confers superinfection immunity on the host . Adjacent, but divergently transcribed, lies another open reading frame whose product resembles the lambda Cro protein . In the 161-bp intergenic segment, putative promoters and operators have been detected.

J Bacteriol, 1998 Jul, 180(13), 3400 - 4
Expression of the bglH gene of Lactobacillus plantarum is controlled by carbon catabolite repression; Marasco R et al.; A newly identified bglH gene coding for a phospho-beta-glucosidase of Lactobacillus plantarum was isolated and expressed in Escherichia coli . The sequence analysis of the cloned DNA fragment showed an open reading frame encoding a 480-amino-acid protein with a calculated molecular mass of 53 kDa . The bglH gene was shown to be expressed on a monocistronic transcriptional unit . Its transcription was repressed 10-fold in L . plantarum cells grown on glucose compared to the beta-glucoside salicin as a sole carbon source . A catabolite-responsive element (CRE) spanning from -3 to +11 with respect to the transcriptional start point was found, and its functionality was assessed by mutational analysis . In vitro and in vivo DNA binding experiments suggested the occurrence of a DNA-protein complex at the CRE site, which would mediate glucose repression of bglH expression.

Exp Parasitol, 1998 Jun, 89(2), 241 - 50
Trichomonas vaginalis: in vitro phagocytosis of lactobacilli, vaginal epithelial cells, leukocytes, and erythrocytes; Rendon-Maldonado JG et al.; This paper explores the interaction of two strains of Trichomonas vaginalis, of high and low virulence, with the cell types present in the microenvironment of the parasite during human infections . With the use of transmission and scanning electron microscopy the sequence of internalization by T . vaginalis of Doderlein's lactobacilli, and of vaginal epithelial cells, leukocytes, and erythrocytes was documented . Furthermore, the degradation of ingested material by colocalization of acid phosphatase activity in phagocytic vacuoles was demonstrated . Phagocytosis of all cell types analyzed was found in both strains studied, although the highly virulent strain internalized target cells more rapidly than the less virulent one . Ultrastructural evidence indicated that phagocytosis takes place through two distinct mechanisms, only one involving the formation of a phagocytic stoma, characteristic of professional phagocytes . T . vaginalis phagocytosis may be both an efficient means of obtaining nutrients for the parasite and a significant factor in the pathogenesis of trichomonal infections of the human genitourinary tract.

J Endod, 1998 Apr, 24(4), 252 - 5
Stimulation of interleukin-6 production in human dental pulp cells by peptidoglycans from Lactobacillus casei; Matsushima K et al.; Interleukin-6 (IL-6), which is a multifunctional cytokine, has an important role in acute and chronic inflammation . The peptidoglycan (PG) was purified from Lactobacillus casei, which was a Gram-positive bacteria frequently isolated from deep carious lesions and suspected to be a pathogen of pulpitis . In this study, the effects of PG on the production of IL-6 in human dental pulp cells were examined . PG stimulated IL-6 production in a time- and dose-dependent manner . Reverse transcriptase-polymerase chain reaction experiments showed that the increase was dependent on the enhancement of IL-6 mRNA levels . These findings suggest that Gram-positive bacteria, such as L . casei, from carious lesions, might be involved in developing pulpitis through the stimulation of IL-6 production.

Curr Microbiol, 1998 Jul, 37(1), 64 - 6
On the iron requirement of lactobacilli grown in chemically defined medium; Imbert M et al.; The iron requirement of four strains of lactobacilli (L . acidophilus, L . delbrueckii subsp . bulgaricus, L . plantarum, and L . pentosus) was studied in a synthetic medium under aerobic or anaerobic conditions . Effects of iron salt and iron-chelated compounds were tested on bacterial growth in manganese-free or -supplemented media . No significant growth stimulation was observed in any condition . These results support the absolute manganese requirement for optimum growth of lactobacilli and the needless incorporation of iron in growth media.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 1998 Jun, 85(6), 680 - 5
Caries in patients with non-insulin-dependent diabetes mellitus; Collin HL et al.; OBJECTIVE: The purpose of this study was to investigate the prevalence and risk factors of dental caries in patients with non-insulin-dependent diabetes mellitus and to determine whether these factors are associated with metabolic control and vascular complications of the disease . STUDY DESIGN: Both the occurrence of caries, acidogenic oral bacteria, and yeasts and salivary flow were studied in 25 patients with non-insulin-dependent diabetes mellitus whose diagnosis had been set 13 to 14 years earlier and in whom the metabolic evolution of the disease was well established . The patients' glycemic control was determined by means of analysis of the blood hemoglobin A1C concentration at the time of dental examination . The control group consisted of 40 nondiabetic subjects in the same age group . Decayed, missing, and filled teeth indices and numbers of surfaces with caries, filled surfaces, and root caries were determined by means of clinical dental caries examination . Stimulated salivary flow was measured, and levels of Streptococcus mutans, lactobacilli, and yeasts were analyzed . RESULTS: The median hemoglobin A1C concentration of the patients was 8.6%, which indicates poor metabolic control of diabetes . No association was found between the metabolic control of disease and dental caries . The occurrence of dental caries was not increased in the patients with non-insulin-dependent diabetes mellitus in comparison with the control subjects . The counts of acidogenic microbes and yeasts did not differ statistically significantly between the groups . There was no association of caries with the prevalence of coronary artery disease or hypertension in either the patients or the control subjects . In a stepwise logistic regression model, a salivary flow of at least 0.8 ml/min was related to the occurrence of dental caries in patients with non-insulin-dependent diabetes mellitus, whereas negligence with respect to dental care was the most important risk predictor in the control group . CONCLUSION: Our results showed no effect of diabetes on the prevalence of caries . However, the caries-protective effect of saliva was partly lost in patients with non-insulin-dependent diabetes mellitus.

Int J Immunopharmacol, 1997 Sep-Oct, 19(9-10), 487 - 92
Clinical study of the effect of the preparation DEODAN on leukopenia, induced by cytostatics; Krusteva E et al.; The aim of the study is to establish the effect of the preparation DEODAN on leukopenia induced by chemotherapeutics in oncological patients . DEODAN is an oral preparation, obtained from lyzozyme lysates of Lactobacillus bulgaricus strain "I . Bogdanov patent strain tumoronecroticance B-51" ATCC 21815, called shortly LB51 . In the study there are included two groups of patients--from National Oncological Centre, Sofia, the other from Clinic of Medicine, Bertha Academic Hospital, Clinics of Duisburg, Duisburg . All the patients, (78) have undergone combined chemotherapy . In all patients, leukopenia has been established in moderate and medium levels . The scheme of the application of DEODAN has been 3 g, three times a day before meals, from the first day of establishing the disturbances of the haemopoesis . The treatment lasted until the restoration of the haematological values . Only DEODAN was applied . The results obtained show that the recovery of the WBC count (values above 3000) took place in all of the patients between days 3 and 5 . None of the patients displayed any infectious or febrile complications, as a result of the applied chemotherapy and the treatment with the preparation . DEODAN also improves the general condition of the patients.

Biochemistry, 1998 Jun 23, 37(25), 9038 - 42
Aspartate 221 of thymidylate synthase is involved in folate cofactor binding and in catalysis; Chiericatti G et al.; Structural studies indicate that Asp 221 of Lactobacilluscasei thymidylate synthase forms a hydrogen bond network with the 2-amino and 3-imino groups of the folate {Matthews, D . A . (1990) J . Mol . Biol . 214, 937-948; Finer-Moore, J . S . (1990)Biochemistry 29, 6977-6986} that has been proposed to participate in catalysis . We prepared a complete replacement set of 19 mutants at position 221 of L . casei thymidylate synthase . Of these, the only one with sufficient activity to complement growth of a thymidylate synthase-deficient host was the Cys mutant . To further elucidate the function of the Asp 221 side chain, seven thymidylate synthase 221 mutants were studied in detail with regard to catalysis of dTMP formation and of thymidylate synthase partial reactions . Most of the mutants bound the nucleotide substrate dUMP with only moderate loss of binding affinity, indicating that the Asp side chain does not contribute to dUMP binding . Most of the mutants catalyzed the cofactor-independent dehalogenation of 5-bromodUMP; hence, the Asp side chain of TS is not essential for addition of the catalytic Cys residue to the nucleotide substrate . Mutants showed decreased affinity for the folate cofactor, but those with side chains capable of hydrogen bond formation were less severely affected . Some of the mutants were capable of forming covalent thymidylate synthase-5-fluorodUMP-methylenetetrahydrofolate complex; hence, the Asp side chain is not essential for steps leading to the covalent complex . We conclude that the hydrogen bond network between Asp 221 and the folate cofactor contributes to cofactor binding and a catalytic step after formation of the covalent ternary complex intermediate.

J Appl Microbiol, 1998 Apr, 84(4), 649 - 60
Evaluation of the extent and type of bacterial contamination at different stages of processing of cooked ham; Samelis J et al.; In an attempt to determine the composition and origin of the spoilage flora of refrigerated vacuum-packed cooked ham, the changes in microbial numbers and types were followed along the processing line . Results revealed Lactobacillus sake and Leuconostoc mesenteroides ssp . mesenteroides as the major causative agents of spoilage of sliced ham stored at 4 degrees C and 12 degrees C, due to recontamination in the cutting room . On the contrary, the progressive deterioration of whole ham under the same storage conditions was associated with a non-identifiable group of leuconostoc-like bacteria . Except for lactic acid bacteria, no other organism grew in vacuum packs of either sliced or whole ham . Although atypical leuconostocs could not be detected among isolates recovered from freshly produced whole ham, they appeared to survive cooking and proliferate during storage . Neither these organisms however, nor Lact . sake and Leuc . mesenteroides were important in curing and tumbling as carnobacteria, mainly Carnobacterium divergens, and Brochothrix thermosphacta dominated at this stage . A progressive inversion of the ham microflora from mostly Gram-negative at the beginning of processing to highly Gram-positive prior to cooking was noted . Listeria monocytogenes cross-contaminated ham during tumbling . However, the pathogen was always absent from the vacuum-packed product provided that heating to a core temperature of 70 degrees C occurred and recontamination during slicing and packing was prevented . The percentage distribution of different species of lactic acid bacteria as well as the uncommon phenotypic characteristics of some strains were discussed.

J Appl Microbiol, 1998 Apr, 84(4), 600 - 6
Characterization of Lactobacillus sake isolates from dry-cured sausages by restriction fragment length polymorphism analysis of the 16S rRNA gene; Sanz Y et al.; Lactobacillus sake strains originally isolated from dry-fermented sausages were characterized by phenotypic and genotypic methods, including DNA-DNA hybridization, restriction fragment length polymorphism (RFLP), and 16S rDNA sequencing analysis, in order to establish their taxonomic position and relation to well defined reference species . Initially, isolates of Lact . sake showing a characteristic phenotype (melibiose-positive, maltose- and arabinose-negative) were identified by DNA-DNA hybridization . Subsequently, RFLP studies using EcoRI and HindIII as restriction enzymes, and cDNA from Escherichia coli or 16S rDNA from Lact . sake strains as probes, showed distinct polymorphism levels . Thus, EcoRI-digested DNA probed with cDNA from E . coli disclosed the presence of a unique cluster for the meat isolates tested, allowing their differentiation from the reference type strain . When HindIII-digested DNA was hybridized with the cDNA probe, strain-specific patterns were obtained, showing a higher discrimination power . Considerable strain differentiation was also observed when EcoRI and HindIII digests were hybridized with 16S rDNA probes . Finally, sequence analysis of the 16S rDNA from one isolate also revealed a certain degree of genetic variability with respect to the reference strain of Lact . sake.

J Appl Microbiol, 1998 Feb, 84(2), 207 - 12
QSARs for the effect of benzaldehydes on foodborne bacteria and the role of sulfhydryl groups as targets of their antibacterial activity; Ramos-Nino ME et al.; Quantitative structure activity relationships (QSARs) were obtained describing the activity of a series of benzaldehydes against three different foodborne bacteria, Listeria monocytogenes F6861, serotype 4b, Salmonella enteritidis, Phage type 4, P167807 and Lactobacillus plantarum INT.L11 . MIC values at pH 6.2 and 35 degrees C were obtained for 11 phenolic benzaldehydes to produce multiple linear regression and artificial neural network models . For each organism, the models contained a steric parameter Vw and an electronic-steric parameter for ortho substituents Es degree . The benzaldehydes did not require to partition to produce their effect, shown by the lack of a lipophilic parameter in the models . This strongly suggests that they act on the outside of the cells . Substitution ortho to the carbonyl group increased their antibacterial action . Cells were treated with 2,3-dihydroxy benzaldehyde and examined for their ability to bind radiolabelled iodoacetate to envelope sulfhydryl groups that remained available . It was shown that the accumulation of radiolabelled iodoacetate was lower after treatment, indicating possible competition between these two compounds for the same target . The order of the sensitivity to benzaldehydes (Salmonella > Listeria > Lactobacillus) correlated with the number of surface sulfhydryl groups available, being highest for Salmonella.

Lett Appl Microbiol, 1998 Apr, 26(4), 248 - 52
A method for the selective enumeration and isolation of ruminal Lactobacillus and Streptococcus; Yanke LJ et al.; Ruminal lactic acid-producing bacteria were selectively isolated and enumerated using a one hour aerobic exposure prior to incubation on a semi-selective Lactobacillus medium, MRS, under anaerobic conditions . The technique allowed growth of pure cultures of ruminal Lactobacillus spp . and Streptococcus bovis without supporting the growth of pure cultures of any of the prominent ruminal bacterial species . In mixed cultures, the one hour aerobic pre-incubation inhibited the growth of the obligate anaerobic ruminal bacteria which can otherwise grow on the MRS medium, and the subsequent anaerobic incubation permitted maximal recovery of the weakly aerotolerant ruminal lactic acid-producing Lactobacillus spp . and Streptococcus spp . The efficacy of this technique in selecting exclusively for the lactic acid-producing bacteria was also demonstrated from populations of rumen bacteria from mixed culture end-point in vitro fermentation, continuous in vitro culture and isolations from fresh ruminal samples.

Int J Food Microbiol, 1998 May 5, 41(1), 45 - 51
Adhesion of some probiotic and dairy Lactobacillus strains to Caco-2 cell cultures; Tuomola EM et al.; The adhesion of 12 different Lactobacillus strains was studied using Caco-2 cell line as an in vitro model for intestinal epithelium . Some of the strains tested have been used as probiotics, and most of them are used in the dairy and food industry . Human and bovine enterotoxigenic Escherichia coli strains were used as positive and negative control, respectively . Bacterial adhesion to Caco-2 cell cultures was quantitated using radiolabelled bacteria . The adherence of bacteria was also observed microscopically after Gram staining . Viability of bacteria prior to adhesion was verified using flow cytometry . Among the tested strains, L . casei (Fyos) was the most adhesive strain and L . casei var . rhamnosus (Lactophilus) was the least adhesive strain, approximately 14 and 3% of the added bacteria adhered to Caco-2 cell cultures, respectively . The corresponding values for positive and negative control E . coli strains were 14 and 4%, respectively . The Lactobacillus strains tested could not be divided into distinctly adhesive or non-adhesive strains, since there was a continuation of adhesion rates . The four most adhesive strains were L . casei (Fyos), L . acidophilus 1 (LC1), L . rhamnosus LC-705 and Lactobacillus GG (ATCC 53103) . No significant differences in the percentage adhesion were observed between these strains . Adhesion of all the strains was dependent on the number of bacteria used, since an approximately constant number of Caco-2 cells was used, indicating that the Caco-2 cell binding sites were not saturated . Viability of bacteria was high since approximately 90% of the bacteria were viable with the exception of L . acidophilus 1 which was 74% viable . Microscopic evaluations agreed with the radiolabelled binding as evidenced by observing more bacteria in Gram-stained preparations of good adhering strains compared to poorly adhering strains.

Int J Food Microbiol, 1998 May 5, 41(1), 1 - 7
Effect of intestinal Lactobacillus starter cultures on the behaviour of Staphylococcus aureus in fermented sausage; Sameshima T et al.; The effects of Lactobacillus strains isolated from intestinal tracts for starter cultures of fermented sausage on the growth rate and enterotoxin production of Staphylococcus aureus were studied at two fermentation temperatures of 20 degrees C and 35 degrees C . Initial inoculated populations in the sausage batter were approx . 10(4) cfu/g for S . aureus and 10(7) cfu/g for the Lactobacillus strain as a starter culture . Samples of sausage were taken during fermentation and analyzed for pH and microbial populations . In control lots without inoculation of Lactobacillus strains, staphylococcal enterotoxin was detected during fermentation at each temperature . Of three intestinal Lactobacillus strains, L . rhamnosus FERM P-15120 and L . paracasei subsp . paracasei FERM P-15121 inhibited the growth and enterotoxin production of S . aureus in sausages during fermentation at both temperatures, although L . acidophilus FERM P-15119 could not satisfactorily suppress them . The effect of the two selected strains in meat fermentation (i.e., fermentation time, acid production, inhibition of S . aureus) was the same as that of a commercial L . sake starter culture for fermented sausage . These results suggest the intestinal Lactobacillus strains selected in this study could be utilized as a starter culture to produce new fermented meat products that are microbiologically safe.

Folia Med (Plovdiv), 1998, 40(1), 34 - 40
Clinical manifestations and diagnosis of bacterial vaginosis in a clinic of sexually transmitted diseases; Tchoudomirova K et al.; BACKGROUND: The aim of the present study was to evaluate the prevalence of bacterial vaginosis (BV) and correlate it with the data from the patient history and clinical manifestations in women attending an STD clinic and to compare two methods of diagnosis . MATERIAL AND METHODS: On hundred and fifty-six women, aged 15 to 45, attending the STD clinic of the Higher Medical Institute in Plovdiv, Bulgaria were enrolled in the study . All women were evaluated for the presence of BV using standard criteria and Gram stain of vaginal secretions . Symptoms, clinical manifestations, methods of contraception and sexual life and smoking were analyzed . RESULTS: Using clinical criteria and Gram's stain, BV was diagnosed in 59 women (37.8%) . BV was associated with age younger than 25 years, risk sexual behaviour, e.g . lack of a permanent sexual partner during the preceding 6 months, use of an intrauterine device, other STDs and smoking . Symptoms are not a reliable way of diagnosing BV, but the presence of a homogeneous vaginal discharge on examination, a positive amine test and pH > or = 4.7 are common in BV . A negative correlation was found between the number of lactobacilli and BV . CONCLUSIONS: BV is common in women attending STD clinic and is associated with other STDs, e.g . infection with Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, human papilloma virus . The Gram stain method is inexpensive and easy to perform for the laboratory diagnosis of BV; it can be used reliably as an indicator of the changes preceding BV.

Biotechnol Prog, 1998 May, 14(3), 537 - 9
Combined influence of growth and drying conditions on the activity of dried lactobacillus plantarum
Linders LJM, Kets EPW, de Bont JAM, van't Riet K.
The production of active dried starter cultures can be influenced at several levels in the production process . In this paper the following process factors are discussed: osmotic stress during growth and cell density prior to drying . Contradicting results are reported in the literature on the influence of osmotic stress during growth on the residual activity after drying . The combined approach in which two process factors were studied at a time resulted in an explanation for the discrepancy in earlier work . The cell density prior to drying had an important influence on the glucose fermenting activity after drying . Residual activities ranging from 0.10 to 0.83 were achieved using initial cell densities between 0.025 and 0.23 g of cell/g of sample, respectively . The drying tolerance of cells grown with osmotic stress of 1 M NaCl was low (residual activity = 0 . 06) and was not related to the cell density prior to drying . The influence of osmotic stress during growth on the drying tolerance of Lactobacillus plantarum was dependent on the cell density prior to drying.

Proc Natl Acad Sci U S A, 1998 Jun 9, 95(12), 6647 - 52
Structural homologies with ATP- and folate-binding enzymes in the crystal structure of folylpolyglutamate synthetase; Sun X et al.; Folylpolyglutamate synthetase, which is responsible for the addition of a polyglutamate tail to folate and folate derivatives, is an ATP-dependent enzyme isolated from eukaryotic and bacterial sources, where it plays a key role in the retention of the intracellular folate pool . Here, we report the 2.4-A resolution crystal structure of the MgATP complex of the enzyme from Lactobacillus casei . The structural analysis reveals that folylpolyglutamate synthetase is a modular protein consisting of two domains, one with a typical mononucleotide-binding fold and the other strikingly similar to the folate-binding enzyme dihydrofolate reductase . We have located the active site of the enzyme in a large interdomain cleft adjacent to an ATP-binding P-loop motif . Opposite this site, in the C domain, a cavity likely to be the folate binding site has been identified, and inspection of this cavity and the surrounding protein structure suggests that the glutamate tail of the substrate may project into the active site . A further feature of the structure is a well defined Omega loop, which contributes both to the active site and to interdomain interactions . The determination of the structure of this enzyme represents the first step toward the elucidation of the molecular mechanism of polyglutamylation of folates and antifolates.

J Dairy Sci, 1998 May, 81(5), 1353 - 7
Increase in milk yield of commercial dairy herds fed a microbial and enzyme supplement; McGilliard ML et al.; A microbial and enzyme supplement fed at 21.2 g/d per cow to 46 Virginia dairy herds increased the milk yield of 31 herds (17 significantly) and decreased the milk yield of 15 herds (7 significantly) . Effects of season were important but consistent with overall results . Herds began receiving the supplement, which contained dried fermentation products of Aspergillus oryzae, Bacillus subtilis, Lactobacillus acidophilus, and yeast culture, midway between the first and second monthly Dairy Herd Improvement tests and continued on the supplement through the 3rd mo . Entry of herds was staggered over 8 mo to reduce the influence of season . The trial involved 3417 cows with 5 test mo between 60 and 365 d in milk . Milk yield during mo 3 averaged 0.64 kg/d per cow more (+0.73 kg/d for first lactation cows and +0.56 kg/d for later lactation cows) than the mean milk yield during mo 1 and 5 . Herds completing the study before summer responded similarly to all other herds, which included herds that were fed the product during summer and those that finished the study during summer . Fat and protein yields and protein percentage differed little with or without the supplement . Fat percentage decreased (0.10%) . Twenty-one herds that were fed a yeast product prior to and during the study responded similarly to the 17 herds that were not fed a yeast product.

J Clin Microbiol, 1998 Jun, 36(6), 1781 - 3
Peritonitis associated with vancomycin-resistant Lactobacillus rhamnosus in a continuous ambulatory peritoneal dialysis patient: organism identification, antibiotic therapy, and case report; Klein G et al.; A case of Lactobacillus rhamnosus-associated peritonitis in a patient undergoing continuous ambulatory peritoneal dialysis is reported . The patient was treated with vancomycin after isolation of glycopeptide-susceptible coagulase-negative staphylococci . After a skin rash developed, vancomycin was discontinued and replaced with teicoplanin . Seven weeks after the glycopeptide therapy was discontinued, a Lactobacillus strain was isolated in pure cultures . The isolate was identified first incorrectly as L . acidophilus but later correctly as L . rhamnosus . Antibiotic susceptibility testing showed that the isolate was resistant to glycopeptides but susceptible to several other antibiotics . The antibiotic treatment was then switched to imipenem and was successful.

Int J Food Microbiol, 1998 Apr 14, 40(3), 169 - 75
Phosphate group requirement for mitogenic activation of lymphocytes by an extracellular phosphopolysaccharide from Lactobacillus delbrueckii ssp . bulgaricus; Kitazawa H et al.; The mitogenic activity of extracellular polysaccharides produced by Lactobacillus delbrueckii ssp . bulgaricus OLL 1073R-1 and NCFB2483 was examined in murine lymphocytes . The extracellular polysaccharide from Lactobacillus delbrueckii ssp . bulgaricus OLL 1073R-1 was fractionated into neutral and acidic polysaccharides by anion-exchange chromatography, while that of Lactobacillus delbrueckii ssp . bulgaricus NCFB2483 were all fractionated into neutral polysaccharide(s) . The acidic polysaccharide stimulated mitogenic responses of murine splenocytes and Peyer's patches but not of thymocytes . The optimal concentration of the acidic polysaccharide at the highest stimulation was 160 microg/ml . A significant increase of mitogenic activity was initiated at 24 h, and the highest response was obtained after stimulation for 48 h . The acidic polysaccharide purified by high performance liquid chromatography also had substantial mitogenic activity, and the molecular weight was estimated to be 1.2 x 10(6) . The acidic polysaccharide was a phosphopolysaccharide consisting of glucose, galactose and phosphorus . Dephosphorylation by hydrofluoric acid degradation reduced the mitogenic activity in lymphocytes . The phosphopolysaccharide produced by Lactobacillus delbrueckii ssp . bulgaricus 1073R-1 is a potent B-cell-dependent mitogen in which the phosphate group acts as a trigger of the mitogenic induction.

Biochemistry, 1998 May 12, 37(19), 6883 - 93
Synthetic interface peptides as inactivators of multimeric enzymes: inhibitory and conformational properties of three fragments from Lactobacillus casei thymidylate synthase; Prasanna V et al.; Three synthetic peptides corresponding to distinct segments of the subunit interface of the dimeric enzyme thymidylate synthase (residues 17-38, N 22; residues 174-190, M 17; and residues 201-220, C 20) have been investigated for their ability to function as inhibitors by modifying the quaternary structure of the enzyme . A dramatic reduction of enzyme activity is observed following incubation of TS with the C 20 peptide . The N 22 and M 17 peptides were unable to cause any loss of enzymatic activity . Addition of the C 20 peptide results in a loss of fluorescence of TS labeled with a dansyl group at Cys 198, following aggregation and precipitation of the protein . The effects are not observed for the N 22 or M 17 peptides . Loss of enzymatic activity is related to the ability of C 20 to promote protein aggregation . The conformations of the peptides have been studied using CD and NMR in order to correlate the observed function with solution structures . Peptides N 22 and M 17 are largely unstructured in aqueous solution . A population of nascent helical structures or multiple turn conformations has been detected for the C 20 peptide in aqueous solution by NMR . Addition of 50% (v/v) hexafluoroacetone trihydrate (HFA), a structure-stabilizing cosolvent, stabilizes the helical conformation in the C 20 peptide . Under similar conditions, N 22 and M 17 remain largely extended with observations of local beta-turn conformations . Interestingly, the C 20 peptide is a beta-hairpin in the native structure, whereas the other two peptides are individual strand components of a beta-sheet.

Protein Eng, 1998 Mar, 11(3), 171 - 83
The separate effects of E60Q in Lactobacillus casei thymidylate synthase delineate between mechanisms for formation of intermediates in catalysis; Birdsall DL et al.; X-Ray crystal structures of Lactobacillus casei thymidylate synthase (TS) mutant complexes of E60D with dUMP, and E60Q with dUMP or FdUMP, as well as ternary complexes with folate analog inhibitor CB3717, are described . The structures we report address the decrease in rate of formation of ternary complexes in the E60 mutants . Structures of ternary complexes of L.casei TS mimic ligand-bound TS just prior to covalent bond formation between ligands and protein . Ternary complex structures of L.casei TS E60Q show the ligands are not optimally aligned for making the necessary covalent bonds . Since CB3717 is an analog of the open, activated form of the cofactor, these structures suggest that the slow rate of ternary complex formation in E60 mutants is at least partly the result of impaired alignment of ligands in the active site after binding and activation of the cofactor . Binary complexes of TS E60Q and TS E60D with substrate (dUMP) show no change in dUMP position or occupancy . These results are consistent with the fact that Kd(dUMP) and Km(dUMP) are almost the same, and the rates of folate-independent debromination of 5-bromo-dUMP are even higher than for wild type TS.

S D J Med, 1998 May, 51(5), 153 - 6
A case of Lactobacillus acidophilus endocarditis successfully treated with cefazolin and gentamicin; Vogt HB et al.; Infective endocarditis secondary to Lactobacillus acidophilus is rare and difficult to treat . Management of patients allergic to penicillin is further complicated by resistance of Lactobacillus organisms to commonly substituted antibiotics . We report a case of a 46-year old woman successfully treated with a prolonged course of cefazolin and gentamicin.

Aust Dent J, 1998 Apr, 43(2), 110 - 6
Enamel cracks . The role of enamel lamellae in caries initiation; Walker BN et al.; Lamellae or cracks are distributed throughout tooth enamel in both deciduous and permanent dentitions . While earlier authors postulated that lamellae may be pathways of entry for caries, no evidence was adduced and the theory appears to have been discounted . The present study seeks to show that, at least in some cases, lamellae are permeable to dyes, may be associated with caries initiated in the dentine, supporting the hypothesis of Hardwick and Manly of lamellae penetration by Streptococcus mutans and lactobacilli . The enamel lamellae are shown to be a permeable pathway allowing caries-producing bacteria access to the dentine-enamel junction . Caries can thus be established within the tooth without visible evidence at the surface.

Stomatologiia (Mosk), 1994 Apr-Jun, 73(2), 17 - 20
{The use of the new bacterial biopreparation Acilact in the combined treatment of periodontitis}; Pozharitskaia MM et al.; Acilact, a bacterial biopreparation representing a complex of live lyophilized acidophilic lactobacteria, was used in combined therapy of 45 patients with periodontitis of mild and medium severity . The drag was applied locally and per os . Clinical parameters improved after therapy; gram-positive cocci and bacilli predominated in local microflora; natural antibacterial resistance of the body improved . This method of therapy is new in principle and pathogenetically grounded . It results in correction of autoflora of the oral cavity and periodontal pouches, and, possibly, of the gastrointestinal tract . Acilact is well tolerated by the patients and induces no side effects, there are no contraindications against its administration.

Gene, 1998 Jun 8, 212(2), 203 - 11
The arbZ gene from Lactobacillus delbrueckii subsp . lactis confers to Escherichia coli the ability to utilize the beta-glucoside arbutin; Weber BA et al.; From a genomic library of the industrially used strain Lactobacillus delbrueckii subsp . lactis DSM7290, a gene designated arbZ (869bp; encoding a 33.5kDa protein) was isolated by screening E . coli transformants for the ability to utilize the beta-glucoside arbutin . Out of 9000 transformants nine were able to ferment arbutin, whereas no utilization of the beta-glucosides salicin, esculin or cellobiose could be detected . Overexpression of arbZ using the T7-polymerase-T7-promoter-system resulted in the formation of insoluble, catalytically inactive protein aggregates (inclusion bodies) . Accordingly, overexpression was not accompanied by an increase in ArbZ activity . Induction of arbZ controlled by the lac promoter under conditions that reduce protein aggregation resulted in a 12-fold increase in arbutin hydrolyzing activity of intact cells and a 13-fold increase in phospho-beta-glycosidase activity in cell-free extracts of the respective transformants . Nucleotide sequence analysis revealed a second gene upstream of arbZ that was designated arbX (830bp) . ArbX (32.6kDa) shared similarity with several glycosyltransferases involved in the biosynthesis of lipopolysaccharides in Gram-negative bacteria . In Lb . delbrueckii subsp . lactis DSM7290 two transcripts, one covering arbX together with arbZ and one covering arbZ alone were detected by Northern blot analysis.

J Oral Rehabil, 1998 Apr, 25(4), 304 - 10
The effect of prosthesis disinfection on salivary microbial levels; Mahonen K et al.; The aim of this study was to evaluate how the soaking of dentures in a disinfection solution affects salivary microbe counts and stomatitis of partially dentate patients . Patients soaked their dentures for 4 weeks randomly both in a disinfection solution and in a placebo solution . Mutans streptococci, lactobacilli and yeast counts were measured before and after each test period and also the flow rate, buffer capacity and pH of saliva were registered . Disinfection decreased all microbe levels investigated, but only lactobacilli counts decreased significantly . Placebo treatment had either no effect on salivary microbe counts or they increased slightly . Disinfection caused some reduction of the mucosal inflammation under the denture base, but could not completely remove stomatitis during the 4-week test period.

Gerodontology, 1997 Jul, 14(1), 17 - 27
Oral glucose clearance in nonagenarians in relation to functional capacity, medication and oral variables; Lundgren M et al.; OBJECTIVES: To study oral sugar (glucose) clearance and to examine some factors which were believed to either influence or be dependent upon oral glucose clearance . DESIGN: Cross-sectional, clinical study with analysis of records . SETTING: Goteborg gerontological and geriatric population studies, Goteborg University, Sweden . SUBJECTS: 71 community-dwelling individuals, 27 men and 44 women, of a representative sample of 260 92-year-old persons . INTERVENTION AND MAIN OUTCOME MEASURES: Glucose concentration was measured in saliva after chewing of a glucose tablet and the clearance was assessed by three different variables: (i) the initial salivary glucose concentration, (ii) the area under the curve (AUC) and (iii) the clearance time . RESULTS: The glucose clearance showed a wide inter-individual variation, which could be explained partly by differences in oral state, chewing time, stimulated salivary secretion rate and medication use . A positive correlation was found between the clearance variables and the number of lactobacilli and mutans streptococci in saliva and the percentage of untreated root caries lesions of the total number of exposed root surfaces . CONCLUSIONS: A slow oral sugar clearance is more common among 92-year-olds than younger adults earlier reported in other studies, particularly in those who have uncompensated functional impairments and a high medication history . A decreased oral glucose clearance was associated with high counts of salivary lactobacilli and mutans streptococci and a high proportion of untreated root caries lesions.

Appl Environ Microbiol, 1998 Jun, 64(6), 2313 - 4
Myoglobin as an inhibitor of exopeptidases from lactobacillus sake
Sanz Y, Toldra F.
The effects of myoglobin on exopeptidases of Lactobacillus sake were determined . Inhibition of the aminopeptidases increased as the myoglobin concentration increased; aminopeptidase 3 was the most affected (90% inhibition) . Aminopeptidases 1, 2, and 4 showed similar inhibition levels (around 60%) . Myoglobin did not affect tripeptidase activity . Thus, myoglobin could limit amino acid generation in meat systems.

Am J Obstet Gynecol, 1998 May, 178(5), S245 - 9
Urogenital aging--a hidden problem; Samsioe G; Urogenital problems in the elderly female population are experienced by one third of women from the age 50 years and onward . Symptoms from the lower urinary tract include incontinence, urethritis, and recurrent urinary tract infections . Atrophic changes within the bladder neck and urethra could be corrected by estrogen administration even at doses so low that endometrial proliferation is avoided . Hence such estrogens could be given without progestogen comedication . Control of micturition is a complex process of which estrogen deficiency is only one of several factors . The aging process with subsequent changes in membrane permeability, neuromuscular function, and collagen synthesis contributes to the local problems of control of micturition . In addition, the central control may also be affected by degenerative changes of the nervous system . Vaginal symptoms comprise dryness of vagina, dyspareunia, and recurrent vaginitis often followed by a foul odor and discharge . The microflora with lactobacilli and low pH as seen in fertile women is gradually replaced by a mixed germ flora including several of the pathogenic organisms common in urinary tract infections . Vaginal pH increases from around 4 to between 6 and 7 . It is a puzzling fact that the urogenital tissues seem to be more "sensitive" to estrogens than other tissues . Conformational changes of the estrogen receptor(s) brought about by the local cytokine milieu is one possibility to explain the situation . The systemic absorption of low-dose estrogen preparations is dependent on the status of the vaginal mucosa . Absorption is high when the vaginal mucosa is atrophic and gradually decreases (but not to zero) as the vaginal mucosa matures under estrogen influence.

Appl Environ Microbiol, 1998 Jun, 64(6), 2269 - 72
Antagonistic activity of Lactobacillus plantarum C11: two new two-peptide bacteriocins, plantaricins EF and JK, and the induction factor plantaricin A; Anderssen EL et al.; Six bacteriocinlike peptides (plantaricin A {PlnA}, PlnE, PlnF, PlnJ, PlnK, and PlnN) produced by Lactobacillus plantarum C11 were detected by amino acid sequencing and mass spectrometry . Since purification to homogeneity was problematic, all six peptides were obtained by solid-phase peptide synthesis and were tested for bacteriocin activity . It was found that L . plantarum C11 produces two two-peptide bacteriocins (PlnEF and PlnJK); a strain-specific antagonistic activity was detected at nanomolar concentrations when PlnE and PlnF were combined and when PlnJ and PlnK were combined . Complementary peptides were at least 10(3) times more active when they were combined than when they were present individually, and optimal activity was obtained when the complementary peptides were present in approximately equal amounts . The interaction between complementary peptides was specific, since neither PlnE nor PlnF could complement PlnJ or PlnK, and none of these peptides could complement the peptides constituting the two-peptide bacteriocin lactococcin G . Interestingly, PlnA, which acts as an extracellular signal (pheromone) that triggers bacteriocin production, also possessed a strain-specific antagonistic activity . No bacteriocin activity could be detected for PlnN.

Appl Environ Microbiol, 1998 Jun, 64(6), 2192 - 9
Development of a probiotic cheddar cheese containing human-derived Lactobacillus paracasei strains; Gardiner G et al.; Cheddar cheese was manufactured with either Lactobacillus salivarius NFBC 310, NFBC 321, or NFBC 348 or L . paracasei NFBC 338 or NFBC 364 as the dairy starter adjunct . These five strains had previously been isolated from the human small intestine and have been characterized extensively with respect to their probiotic potential . Enumeration of these strains in mature Cheddar cheese, however, was complicated by the presence of high numbers (>10(7) CFU/g of cheese) of nonstarter lactic acid bacteria, principally composed of lactobacilli which proliferate as the cheese ripens . Attempts to differentiate the adjunct lactobacilli from the nonstarter lactobacilli based on bile tolerance and growth temperature were unsuccessful . In contrast, the randomly amplified polymorphic DNA method allowed the generation of discrete DNA fingerprints for each strain which were clearly distinguishable from those generated from the natural flora of the cheeses . Using this approach, it was found that both L . paracasei strains grew and sustained high viability in cheese during ripening, while each of the L . salivarius species declined over the ripening period . These data demonstrate that Cheddar cheese can be an effective vehicle for delivery of some probiotic organisms to the consumer.

Appl Environ Microbiol, 1998 Jun, 64(6), 2013 - 9
The gal genes for the Leloir pathway of Lactobacillus casei 64H; Bettenbrock K et al.; The gal genes from the chromosome of Lactobacillus casei 64H were cloned by complementation of the galK2 mutation of Escherichia coli HB101 . The pUC19 derivative pKBL1 in one complementation-positive clone contained a 5.8-kb DNA HindIII fragment . Detailed studies with other E . coli K-12 strains indicated that plasmid pKBL1 contains the genes coding for a galactokinase (GalK), a galactose 1-phosphate-uridyltransferase (GalT), and a UDP-galactose 4-epimerase (GalE) . In vitro assays demonstrated that the three enzymatic activities are expressed from pKBL1 . Sequence analysis revealed that pKBL1 contained two additional genes, one coding for a repressor protein of the LacI-GalR-family and the other coding for an aldose 1-epimerase (mutarotase) . The gene order of the L . casei gal operon is galKETRM . Because parts of the gene for the mutarotase as well as the promoter region upstream of galK were not cloned on pKBL1, the regions flanking the HindIII fragment of pKBL1 were amplified by inverse PCR . Northern blot analysis showed that the gal genes constitute an operon that is transcribed from two promoters . The galKp promoter is inducible by galactose in the medium, while galEp constitutes a semiconstitutive promoter located in galK.

Microbiol Res, 1998 Apr, 153(1), 29 - 35
Release of spirosin associated with potassium phosphate-induced autolysis in Lactobacillus reuteri DSM 20016; Yamato M et al.; We have studied the effect of medium components on spirosin production in Lactobacillus reuteri DSM 20016 to get some insight into the function of spirosome in Lactobacillus . Among those investigated, only potassium phosphate was found to influence the production of spirosin . Though it was not effective at concentrations lower than 0.6%, it promoted the spirosin production and its accumulation into culture medium in particular, at higher concentrations . The accumulation has been demonstrated to originate inthe release of spirosin due to the bacterial autolysis induced by the higher concentrations of potassium phosphate, The autolytic effect of potassium phosphate was assumed to be a concerted action by phosphate and potassium ions at the concentrations higher than 0.1 and 0.4 M, respectively . A possible role of spirosin as a sensor protein of bacterial two-component regulatory system was discussed.

Arch Oral Biol, 1998 Feb, 43(2), 151 - 6
Stimulated salivary flow rate and composition in asthmatic and non-asthmatic adults; Lenander-Lumikari M et al.; The number of decayed, missed and filled permanent teeth (DMFT), the degree of periodontal inflammation (Periodontal Status Index, PSI), stimulated salivary flow rate and the concentrations of total protein, lactoferrin, lysozyme, myeloperoxidase, salivary peroxidase, calcium, potassium, sodium and thiocyanate in whole saliva of 26 adult asthma patients were compared with those of 33 non-asthmatic controls . The saliva was also analysed for mutans streptococci, lactobacilli, total anaerobic flora and Candida spp . The mean PSI (p < 0.05; 95% confidence interval for the difference between means (95% CI) 2.47-25.30) was higher and the mean stimulated salivary flow rate (p < or = 0.05; 95% CI 0.57-0.55) was lower in the asthmatic group than in the control group . No differences were found between the groups in non-immune defense factors, except for myeloperoxidase . The myeloperoxidase concentrations were higher in asthmatics than in non-asthmatics (p < 0.05; 95% CI 4.4-134.0 ng/ml) . No differences in microbial counts were found . It was concluded that stimulated salivary flow rates decrease while myeloperoxidase concentrations increase in adult asthmatic patients compared with non-asthmatic adults . The higher concentrations of myeloperoxidase are explained by a higher PSI in asthmatics.

Arch Oral Biol, 1998 Feb, 43(2), 103 - 10
Binding properties of streptococcal glucosyltransferases for hydroxyapatite, saliva-coated hydroxyapatite, and bacterial surfaces; Vacca-Smith AM et al.; The binding specificities of Streptococcus glucosyltransferase (Gtf) B, C and D for hydroxyapatite (HA), saliva-coated hydroxyapatite (SHA), and bacterial surfaces were examined . For HA beads the following values were obtained: (K = affinity; N = number of binding sites) GtfB, K = 46 x 10(5) ml/mumol, N = 0.65 x 10(-6) mumol/m2; GtfC, K = 86 x 10(5) ml/mumol, N = 4.42 x 10(-6) mumol/m2.; GtfD, K = 100 x 10(5) ml/mumol, N = 0.83 x 10(-6) mumol/m2 . For SHA beads, the following values were obtained: GtfB, K = 14.7 x 10(5) ml/mumol, N = 1.03 x 10(-6) mumol/m2; GtfC, K = 21.3 x 10(5) ml/mumol, N = 3.66 x 10(-6) mumol/m2; GtfD, K = 1.73 x 10(5) ml/mumol, N = 8.88 x 10(-6) mumol/m2 . The binding of GtfB to SHA beads was reduced in the presence of parotid saliva, but the binding of GtfC and D was unaffected . The binding of GtfB to SHA in the presence of parotid saliva supplemented with GtfC and D was reduced when compared with its binding to SHA in the presence of parotid saliva alone . In contrast, te binding of GtfC and SHA was unaffected when parotid saliva was supplemented with the other Gtf enzymes . GtfB bound to several bacterial strains (Strep, mutans GS-5, Actinomyces viscosus OMZ105E and Lactobacillus casei 4646) in an active form, while GtfC and D did not bind to bacterial surfaces . It is concluded that of the three Gtf enzymes, GtfC has the highest affinity for HA and SHA surfaces and can adsorb on the the SHA surface in the presence of the other two enzymes . GtfD also binds to SHA in the presence of the other enzymes but has a very low affinity for the surface . GtfB does not bind to SHA in the presence of the other Gtf enzymes but binds avidly to bacterial surfaces in an active form . Therefore, GtfC most probably binds to apatitic surfaces, while GtfB binds to bacterial surfaces.

Int J Paediatr Dent, 1995 Sep, 5(3), 149 - 55
Dental caries and prolonged breast-feeding in 18-month-old Swedish children; Hallonsten AL et al.; Three thousand children aged 18 months were screened for dental caries and ongoing breast-feeding at 46 child welfare centres in different parts of Sweden . Of these, 200 children were selected for a more comprehensive examination, involving investigation of dietary, toothbrushing and sucking habits, use of fluoride, and determination of salivary levels of mutans streptococci and lactobacilli . The children were divided into four groups: group 1: children with caries not being breast-fed; group 2: children with caries being breast-fed; group 3: caries-free children being breast-fed; group 4: caries-free gender- and age-matched reference children not being breast-fed . The results showed that 63 of the children (2.1%) had caries and 61 (2.0%) were still being breast-fed . Twelve (19.7%) of the 61 children still being breast-fed had caries compared with 51 (1.7%) of the 2939 children not being breast-fed; the difference was statistically significant . Children with caries and still being breast-fed had a mean defs of 5.3, and those with caries not being breast-fed 4.9; the difference was not statistically significant . Children with caries, irrespective of whether they were being breast-fed or not, had significantly higher numbers of cariogenic food intakes per day than caries-free children . Mutans streptococci were detected in 67% of the children and lactobacilli in 13% . Children with detectable mutans streptococci and lactobacilli had significantly more caries than those without . The results indicate that Swedish children with prolonged breast-feeding have a tendency to establish unsuitable dietary habits which constitutes a risk situation for developing caries at an early age.

J Biol Chem, 1998 May 22, 273(21), 12929 - 34
Activation of thiamin diphosphate and FAD in the phosphatedependent pyruvate oxidase from Lactobacillus plantarum; Tittmann K et al.; The phosphate- and oxygen-dependent pyruvate oxidase from Lactobacillus plantarum is a homotetrameric enzyme that binds 1 FAD and 1 thiamine diphosphate per subunit . A kinetic analysis of the partial reactions in the overall oxidative conversion of pyruvate to acetyl phosphate and CO2 shows an indirect activation of the thiamine diphosphate by FAD that is mediated by the protein moiety . The rate constant of the initial step, the deprotonation of C2-H of thiamine diphosphate, increases 10-fold in the binary apoenzyme-thiamine diphosphate complex to 10(-2) s-1 . Acceleration of this step beyond the observed overall catalytic rate constant to 20 s-1 requires enzyme-bound FAD . FAD appears to bind in a two-step mechanism . The primarily bound form allows formation of hydroxyethylthiamine diphosphate but not the transfer of electrons from this intermediate to O2 . This intermediate form can be mimicked using 5-deaza-FAD, which is inactive toward O2 but active in an assay using 2,6-dichlorophenolindophenol as electron acceptor . This analogue also promotes the rate constant of C2-H dissociation of thiamine diphosphate in pyruvate oxidase beyond the overall enzyme turnover . Formation of the catalytically competent FAD-thiamine-pyruvate oxidase ternary complex requires a second step, which was detected at low temperature.

Int J Food Microbiol, 1998 Mar 3, 40(1-2), 87 - 92
Development of a growth medium suitable for exopolysaccharide production by Lactobacillus delbrueckii ssp . bulgaricus RR; Kimmel SA et al.; Complex media are commonly used in studies examining exopolysaccharide production by Lactobacillus delbrueckii ssp . bulgaricus . However, quantification of exopolysaccharide in complex medium can be complicated by interference due to carbohydrate polymers contained in media components . This study was undertaken to identify components of MRS, a common medium for cultivation of L . delbrueckii ssp . bulgaricus, that interfere with exopolysaccharide quantification, to develop a medium for production of exopolysaccharide that provides for growth of L . delbrueckii ssp . bulgaricus strain RR similar to MRS, and to demonstrate exopolysaccharide production by L . delbrueckii ssp . bulgaricus RR grown in the newly developed medium . Phenol-sulfuric acid determinations were conducted on uninoculated MRS broth with and without yeast extract, beef extract and proteose peptone #3 . These three ingredients accounted for 94% of the total background exopolysaccharide-equivalent in MRS broth . Based on these results, a semi-defined medium (SDM) providing minimal interference was developed using yeast nitrogen base and Bacto casitone . Growth of L . delbrueckii ssp . bulgaricus RR at 42 degrees C in semi-defined medium and MRS was evaluated, and generation times did not differ significantly (0.94 h in MRS and 0.85 h in SDM) . Exopolysaccharide production by L . delbrueckii ssp . bulgaricus RR during growth in semi-defined medium was evaluated at 30 and 40 degrees C . The rate of exopolysaccharide production was lower at 30 degrees C (8.04 (mg/l-h) than at 40 degrees C (11.95 (mg/l-h), but the maximal concentration of exopolysaccharide produced was similar at both temperatures.

Int J Food Microbiol, 1998 Mar 3, 40(1-2), 43 - 9
Improvement of garri quality by the inoculation of microorganisms into cassava mash; Okafor N et al.; Lactobacillus delbruckii, Lactobacillus coryneformis, and a Saccharomyces sp., previously found among 214 isolates to be the highest producers of linamarase, amylase, and lysine were inoculated separately or mixed into cassava mash and fermented with, or without dewatering, for 24, 48, 72, 96 and 120 h . At the end of the fermentation period, the mash was converted to garri by heating over a gas burner . The mash and the garri resulting from it were assessed for lysine and residual cyanide, while the garri was also studied for its organoleptic properties . The inoculation of the microorganisms into cassava mash produced a sharp drop in the cyanide content of the mash, particularly when the mixture of organisms was inoculated into undewatered cassava mash rather the single organisms . After 24 h, while the cyanide content of the control (uninoculated mash) mash was 3.06 microg/g in the dewatered mash, and 4.24 microg/g in the undewatered mash, the inoculation of a mixture of the three organisms caused the cyanide content in the inoculated mashes to drop by 150% to 1.96 microg/g (dewatered mash) and by 300% to 1.43 microg/g (undewatered mash) . It also appears that the process of producing the garri from the mash by heating, caused a further reduction of the cyanide content: thus the garri always contained less cyanide than the mash from which it was made . The lysine content of the mash was also highest when all three organisms were mixed; it also tended to increase with increasing length of fermentation of the mash . Whereas the single organism most effective in reducing the cyanide content of mash was Lactobacillus delbruckii, in the case of lysine production, it was the yeast . The organoleptic properties of the garri which were assessed were flavour, texture, colour and general acceptability . In general these properties were superior at the P < 0.01 level in garri made from the undewatered mash in comparison with that from dewatered mash, especially when the mixture of organisms was used . The inoculation of the mixture of the three organisms produced a dramatic reduction in the time (24 h) taken for the highest 'general acceptability' score to be given by the tasters when compared with the singly inoculated organisms and the control, which attained this characteristic after about 96 h of incubation in mash.

Int J Food Microbiol, 1998 Mar 3, 40(1-2), 17 - 25
Plantaricin LP84, a broad spectrum heat-stable bacteriocin of Lactobacillus plantarum NCIM 2084 produced in a simple glucose broth medium; Suma K et al.; Lactobacillus plantarum NCIM 2084 produced an antibacterial substance when grown at 40 degrees C for 36 h in a laboratory medium . The antibacterial substance was active against a wide range of bacteria comprising Gram positive and negative foodborne pathogenic and spoilage bacteria . However, related mesophilic lactobacilli were not inhibited, except for L . amylovorus DSM 20531 . The antimicrobial activity was observed between late log and stationary growth phases . The antibacterial substance was partially purified through concentration under vacuum, followed by extraction with methanol and acetone (M-A extract) . On fractionation of the M-A extract through Sephadex G-25, the activity was present in an eluant volume of 85 to 100 ml (peak I), indicating an apparent molecular mass of between 1 and 5 kDa and the purification attained was 80-fold . The antimicrobial principle was stable to heat (121 degrees C for 20 min) and catalase, but sensitive to trypsin and chymotrypsin, indicating it to be a bacteriocin . The M-A extract exhibited a bactericidal and lytic effect against Bacillus cereus F 4810 and Escherichia coli D 21 . The ability of L . plantarum NCIM 2084 to produce an effective bacteriocin in a simple growth medium is of potential interest in its application as a biopreservative in traditional fermented foods.

Gene, 1998 Mar 27, 210(1), 61 - 70
Structure of a genome region of the Lactobacillus gasseri temperate phage phiadh covering a repressor gene and cognate promoters; Engel G et al.; By sequencing the DNA regions which flank the intG gene encoding integrase of the temperate Lactobacillus (Lb.) gasseri bacteriophage phiadh, a continuous sequence of 6590 bp was established . It encompasses five newly identified ORFs, of which four are located upstream, and one (orfC) downstream of intG . Proteins corresponding to the expected products of the intG upstream coding regions, orfA (33 kDa), orf2 (14 kDa), rad (12.1 kDa), and tec (7.9 kDa), were identified by in vitro expression of subcloned DNA fragments . Rad shares homology with transcription regulators, including SinR of Bacillus species and the repressor of phage phi105 . The gporf2 is similar to predicted products of topologically equivalent coding regions of the Lactococcus lactis phage TP901-1 and the B . subtilis phage phi105 . Promoters for the divergently oriented rad and tec genes were mapped within the 435-bp region between them and specify overlapping transcripts with extended 5'-untranslated sequences . As shown with lacZ fusions, Rad repressed transcription from the tec and rad promoters 20- and 5-fold, respectively . In Lb . gasseri, weak expression of cloned rad ws sufficient to mediate immunity towards phiadh.

J Dent, 1998 Mar, 26(3), 267 - 71
Antibacterial activity of dentine primer containing MDPB after curing; Imazato S et al.; OBJECTIVES: A monomer methacryloyloxydodecylpyridinium bromide (MDPB) has antibacterial activity before polymerization . Furthermore, the antibacterial agent is immobilized by the polymerization of MDPB and the resin-based material incorporating MDPB is able to show an antibacterial effect even after being cured . The purpose of this study was to investigate the antibacterial effect of a dentine primer containing MDPB after curing . METHODS: The inhibitory effect of a cured MDPB-containing primer on the growth of Streptococcus mutans, Actinomyces viscosus and Lactobacillus casei was determined by the agar-disc method . The bactericidal activity of cured primer during a 1-h contact period was assessed using S . mutans, and the elution of unpolymerized MDPB was measured with high performance liquid chromatography . RESULTS: Cured MDPB-containing primer showed an inhibitory effect on the growth of all species which were in contact with the specimen surface, and displayed a little bactericidal effect on S . mutans without releasing any unpolymerized antibacterial components . CONCLUSION: Incorporation of antibacterial monomer MDPB into dentine primer is beneficial for providing antibacterial activity after curing.

J Infect Dis, 1998 May, 177(5), 1386 - 90
Effect on normal vaginal flora of three intravaginal microbicidal agents potentially active against human immunodeficiency virus type 1; Rosenstein IJ et al.; The effect on normal vaginal flora of three intravaginal microbicides potentially active against human immunodeficiency virus type 1 was examined . Volunteers received dextrin sulfate (D2S), nonoxynol-9 (N-9), or docusate sodium in separate placebo-controlled studies . High vaginal swabs were obtained for bacterial culture before and after microbicide application . D2S did not affect the vaginal flora . However, lactobacilli decreased by > or = 10(2) cfu/mL in 9 (56%) of 16 women given N-9 and in 5 (63%) of 8 women given docusate sodium . Women using N-9 were also significantly more likely to become colonized abnormally (usually with aerobic gram-negative rods) than were those using placebo, as were women using docusate sodium . Women with reduced lactobacilli were less likely to regain normal flora than were those whose lactobacilli were unaffected . However, coliform colonization occurred whether lactobacilli produced H2O2 or not . Continuous use of N-9 could induce susceptibility to urinary and gynecological infection . It is essential that potential microbicides are examined for activity against normal vaginal flora.

Ginekol Pol, 1998 Feb, 69(2), 82 - 6
{The presence of staphylococci in the vagina of pregnant women}; Krzeminski Z et al.; We were investigating the colonisation rate as well as the quantity of staphylococci in the vagina of women with physiological and complicated pregnancy . We have found high frequency of staphylococci (coagulase-negative and/or coagulase-positive) . Vaginal carriage rate amount 90% . According to our results neither the presence nor the quantity of these microorganisms were related to the presence or the number of lactobacilli, among them to the hydrogen peroxide producing ones . We have also assumed that neither colonisation nor the quantity of staphylococci have any influence on the course of pregnancy.

J Dent Assoc S Afr, 1998 Jan, 53(1), 3 - 6
Lactobacillus species associated with active caries lesions; Botha SJ et al.; Lactobacilli that are most frequently associated with active caries lesions in dentine were isolated and identified as part of a research project which aims to determine the role of the predominant species of these organisms in the carious process . Samples of carious dentine were collected from 12 patients with open caries lesions (Group A) and stimulated saliva samples were collected from 12 patients with a DMFT = 0 and confirmed presence of lactobacilli in the oral cavity (Group B) . After serial dilutions samples were plated on Rogosa agar and incubated anaerobically at 37 degrees C for 48 hours . Representative colonies were isolated from each sample, using Harrison's disc and species were identified by classical taxonomy . A total of 153 isolates were identified . The redefinition and description of lactobacilli species in recent systematic literature resulted in a new and different species composition of oral lactobacilli as shown in this study, namely: homofermentative species (Group A = 82 per cent; Group B = 90 per cent) were predominantly Lactobacillus paracasei (Group A = 39 per cent; Group B = 30 percent) and Lactobacillus rhamnosus (Group A = 31 per cent; Group B = 41 per cent) . Heterofermentative species (Group A = 18 per cent; Group B = 10 per cent) were predominantly Lactobacillus fermentum (Group A = 68 per cent; Group B = 100 percent).

Eur J Oral Sci, 1998 Apr, 106(2 Pt 1), 616 - 22
Intra-individual variations of salivary microbial levels in young adults; Petti S et al.; The variations of salivary levels of total viable flora, oral streptococci, Streptococcus mutans, Lactobacillus and Candida in twenty-three subjects, over a 6-month period, trying to control many potential sources of variability, were investigated . Most subjects showed log count variations of the microbial parameters larger than 1 . They were 95.6% (total flora), 91.2% (oral streptococci), 73.9% (lactobacilli), 60.8% (Strep . mutans) and 30.3% (Candida) . The intra-individual fluctuations were larger than the fluctuations of the means of the counts between samples . This suggests that the shifts in levels of these micro-organisms were more frequent intra-individually than at a population level . Strep . mutans levels significantly explained Streptococcus-Oral (inverse correlation), Lactobacillus and Candida variability . The reported variations were due to technical and biological factors and suggest that, in order to assess the salivary level of some microbial parameters in an individual, the mean count and the range of counts, obtained by more than two samples taken under the same conditions, should be considered.

Spec Care Dentist, 1997 Mar-Apr, 17(2), 65 - 9
The level of cariogenic micro-organisms in patients with Sjögren's syndrome; Kolavic SA et al.; Sixteen patients with caries-inactive sjogren's syndrome with low parotid salivary flow rates (< 0.25 mL/min) and 18 caries-inactive control subjects with higher salivary flow rates were compared . Mutans streptococci (MS) and lactobacilli (LB) counts were measured by means of Dentocult SM strip mutans and LB assays . The group with Sjogren's syndrome displayed higher counts of MS (P = 0.014) and LB (p = 0.003) when compared with controls . The results of this study indicate that patients with caries-inactive Sjogren's syndrome and low salivary flow may have higher colonization of cariogenic micro-organisms than healthy individuals.

Biochemistry, 1998 Apr 21, 37(16), 5528 - 35
Gemcitabine 5'-triphosphate is a stoichiometric mechanism-based inhibitor of Lactobacillus leichmannii ribonucleoside triphosphate reductase: evidence for thiyl radical-mediated nucleotide radical formation; Silva DJ et al.; Ribonucleoside triphosphate reductase (RTPR) from Lactobacillus leichmannii utilizes adenosylcobalamin and catalyzes the conversion of nucleoside triphosphates to deoxynucleoside triphosphates . One equivalent of 2',2'-difluoro-2'-deoxycytidine 5'-triphosphate, F2dCTP, rapidly inactivates RTPR . Analysis of the reaction products reveals that inactivation is accompanied by release of two fluoride ions and 0.84 equiv of 5'-deoxyadenosine and attachment of 1 equiv of corrin covalently to an active-site cysteine residue of RTPR . No cytosine release was detected . Proteolysis of corrin-labeled RTPR with endoproteinase Glu-C and peptide mapping at pH 5.8 revealed that C419 was predominantly modified . The kinetics of the inactivation have been examined by stopped-flow (SF) UV-vis spectroscopy and rapid freeze quench (RFQ) electron paramagnetic resonance (EPR) spectroscopy . Monitoring DeltaA525 nm shows that cob(II)alamin is formed with an apparent kobs of 50 s-1, only 2 . 5-fold slower than a similar experiment carried out with cytidine 5'-triphosphate (CTP) . The same reaction mixture was thus quenched at times from 22 ms to 30 s and examined by EPR spectroscopy . At early time points the EPR spectrum resembled a thiyl radical exchange coupled to cob(II)alamin . From 22 to 255 ms the total spin concentration remained unchanged at 1.4 spins/RTPR, twice that predicted by the amount of cob(II)alamin determined by SF . However, with time the signal attributed to the thiyl radical-cob(II)alamin disappears and new signal(s) with broad feature(s) at g = 2.33 and a sharp feature at g = 2.00 appeared, suggesting formation of cob(II)alamin and a nucleotide-based radical with only dipolar interactions . These studies have been interpreted to support the proposal that an RTPR-based thiyl radical can give rise to a nucleotide-based radical.

Int J Food Microbiol, 1998 Feb 17, 39(3), 205 - 11
Lactic acid fermentation and storage of blanched garlic; de Castro A et al.; The controlled fermentation of peeled, blanched garlic, using a starter culture of Lactobacillus plantarum, was studied and compared with that of unblanched garlic . Blanching was carried out in hot water (90 degrees C) for 15 min . The starter grew abundantly in the case of blanched garlic, producing mainly lactic acid and reaching a pH of 3.8 after 7 days, but its growth was inhibited in unblanched garlic . Ethanol and fructose, coming from enzymatic activities of the garlic, and a green pigment were formed during the fermentation of unblanched garlic, but not of blanched garlic . The blanched garlic fermented by L . plantarum, even without a preservation treatment (pasteurization), was microbiologically stable during storage at 30 degrees C in an acidified brine (approximately 3% (w/w) NaCl and pH 3.5 at equilibrium), but fructans were hydrolyzed . The packed fermented product and that obtained by direct packing without fermentation were not significantly different with regard to flavour.

J Bacteriol, 1998 Mar, 180(6), 1381 - 8
Characterization of IS1515, a functional insertion sequence in Streptococcus pneumoniae; Munoz R et al.; We describe the characterization of a new insertion sequence, IS1515, identified in the genome of Streptococcus pneumoniae I41R, an unencapsulated mutant isolated many years ago (R . Austrian, H . P . Bernheimer, E . E . B . Smith, and G . T . Mills, J . Exp . Med . 110:585-602, 1959) . A copy of this element located in the cap1EI41R gene was sequenced . The 871-bp-long IS1515 element possesses 12-bp perfect inverted repeats and generates a 3-bp target duplication upon insertion . The IS encodes a protein of 271 amino acid residues similar to the putative transposases of other insertion sequences, namely IS1381 from S . pneumoniae, ISL2 from Lactobacillus helveticus, IS702 from the cyanobacterium Calothrix sp . strain PCC 7601, and IS112 from Streptomyces albus G . IS1515 appears to be present in the genome of most type 1 pneumococci in a maximum of 13 copies, although it has also been found in the chromosome of pneumococcal isolates belonging to other serotypes . We have found that the unencapsulated phenotype of strain 141R is the result of both the presence of an IS1515 copy and a frameshift mutation in the cap1EI41R gene . Precise excision of the IS was observed in the type 1 encapsulated transformants isolated in experiments designed to repair the frameshift . These results reveal that IS1515 behaves quite differently from other previously described pneumococcal insertion sequences . Several copies of IS1515 were also able to excise and move to another locations in the chromosome of S . pneumoniae . To our knowledge, this is the first report of a functional IS in pneumococcus.

Microbiology, 1998 Apr, 144 ( Pt 4), 905 - 14
An operon encoding three glycolytic enzymes in Lactobacillus delbrueckii subsp . bulgaricus: glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase and triosephosphate isomerase; Branny P et al.; The structural genes gap, pgk and tpi encoding three glycolytic enzymes, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), 3-phosphoglycerate kinase (PGK) and triosephosphate isomerase (TPI), respectively, have been cloned and sequenced from Lactobacillus delbrueckii subsp . bulgaricus (L . bulgaricus) . The genes were isolated after screening genomic sublibraries with specific gap and pgk probes obtained by PCR amplification of chromosomal DNA with degenerate primers corresponding to amino acid sequences highly conserved in GAPDHs and PGKs . Nucleotide sequencing revealed that the three genes were organized in the order gap-pgk-tpi . The translation start codons of the three genes were identified by alignment of the N-terminal sequences . These genes predicted polypeptide chains of 338, 403 and 252 amino acids for GAPDH, PGK and TPI, respectively, and they were separated by 96 bp between gap and pgk, and by only 18 bp between pgk and tpi . The codon usage in gap, pgk, tpi and three other glycolytic genes from L . bulgaricus differed, noticeably from that in other chromosomal genes . The site of transcriptional initiation was located by primer extension, and a probable promoter was identified for the gap-pgk-tpi operon . Northern hybridization of total RNA with specific probes showed two transcripts, an mRNA of 1.4 kb corresponding to the gap gene, and a less abundant mRNA of 3.4 kb corresponding to the gap-pgk-tpi cluster . The absence of a visible terminator in the 3'-end of the shorter transcript and the location of this 3'-end inside the pgk gene indicated that this shorter transcript was produced by degradation of the longer one, rather than by an early termination of transcription after the gap gene.

Caries Res, 1998, 32(3), 166 - 74
Five-year incidence of caries, salivary and microbial conditions in 60-, 70- and 80-year-old Swedish individuals; Fure S; The 5-year incidence of dental caries in a random sample of 60-, 70- and 80-year-old inhabitants of Goteborg was related to salivary and microbial conditions . Of the 208 persons examined at baseline, 148 (71%) participated in the follow-up examination; 69, 51 and 28, respectively, in the different age groups . The study revealed that 27% of the participants had not developed any carious lesions during the 5-year period and that the incidence of coronal and root caries increased with age . In the 60-year-olds, 2.5% of the susceptible coronal and root surfaces, respectively, had decayed, while the corresponding figures for the 80-year-olds were 8.8% for coronal surfaces and 9.8% for root surfaces . In all, 18% had an unstimulated saliva secretion rate of below 0.1 ml/min and 14% had a stimulated secretion rate of <0.7 ml/min, with a mean rate which decreased with increasing age from 2.0 to 1.6 and 1.3 ml/min (p = 0.02) . The overall salivary counts of lactobacilli and mutans streptococci, particularly the subspecies of Streptococcus sobrinus, had increased during the period . In the respective age groups of 60, 70 and 80 years, 15, 39 and 39% had a mutans streptococci count of > or = 10(6) CFU/ml in saliva and the corresponding figures for > or = 10(5) lactobacilli counts were 22, 31 and 43% . In the stepwise regression analysis, it was found that age, salivary levels of mutans streptococci and lactobacilli and number of teeth were the best predictors of the incidence of root caries . In conclusion, these observations indicate that there is an increased risk of dental caries with age owing to unfavourable microbial and salivary conditions.

J Bacteriol, 1998 May, 180(9), 2312 - 20
Cloning, sequence analysis, and characterization of the genes involved in isoprimeverose metabolism in Lactobacillus pentosus; Chaillou S et al.; Two genes, xylP and xylQ, from the xylose regulon of Lactobacillus pentosus were cloned and sequenced . Together with the repressor gene of the regulon, xylR, the xylPQ genes form an operon which is inducible by xylose and which is transcribed from a promoter located 145 bp upstream of xylP . A putative xylR binding site (xylO) and a cre-like element, mediating CcpA-dependent catabolite repression, were found in the promoter region . L . pentosus mutants in which both xylP and xylQ (LPE1) or only xylQ (LPE2) was inactivated retained the ability to ferment xylose but were impaired in their ability to ferment isoprimeverose (alpha-D-xylopyranosyl-(1,6)-D-glucopyranose) . Disruption of xylQ resulted specifically in the loss of a membrane-associated alpha-xylosidase activity when LPE1 or LPE2 cells were grown on xylose . In the membrane fraction of wild-type bacteria, alpha-xylosidase could catalyze the hydrolysis of isoprimeverose and p-nitrophenyl-alpha-D-xylopyranoside with apparent Km and Vmax values of 0.2 mM and 446 nmol/min/mg of protein, and 1.3 mM and 54 nmol/min/mg of protein, respectively . The enzyme could also hydrolyze the alpha-xylosidic linkage in xyloglucan oligosaccharides, but neither methyl-alpha-D-xylopyranoside nor alpha-glucosides were substrates . Glucose repressed the synthesis of alpha-xylosidase fivefold, and 80% of this repression was released in an L . pentosus delta ccpA mutant . The alpha-xylosidase gene was also expressed in the absence of xylose when xylR was disrupted.

Infect Immun, 1998 May, 66(5), 1985 - 9
Adherence of human vaginal lactobacilli to vaginal epithelial cells and interaction with uropathogens; Boris S et al.; Three strains of Lactobacillus, identified as Lactobacillus acidophilus, Lactobacillus gasseri, and Lactobacillus jensenii, were selected from among 70 isolates from the vaginas of healthy premenopausal women for properties relevant to mucosal colonization or antagonism . All three self-aggregated and adhered to epithelial vaginal cells, displacing well-known vaginal pathogens, such as G . vaginalis, and inhibiting the growth in vitro of Escherichia coli and Streptococcus agalactiae . The surface components involved in self-aggregation appeared to be proteins for L . gasseri and lipoproteins for L . acidophilus and L . jensenii, as judged by susceptibility to treatment with appropriate degrading enzymes . The factors responsible for adherence to epithelial vaginal cells seemed to be glycoproteins (L . acidophilus and L . gasseri) and carbohydrate (L . jensenii) . The receptors of the vaginal cells were glycolipids, which presumably were the targets of the competition observed between the lactobacilli and the pathogenic microbes.

Appl Environ Microbiol, 1998 May, 64(5), 1871 - 7
Molecular analysis of the locus responsible for production of plantaricin S, a two-peptide bacteriocin produced by Lactobacillus plantarum LPCO10; Stephens SK et al.; A 4.5-kb region of chromosomal DNA carrying the locus responsible for the production of plantaricin S, a two-peptide bacteriocin produced by Lactobacillus plantarum LPCO10 (R . Jimenez-Diaz, J . L . Ruiz-Barba, D . P . Cathcart, H . Holo, I . F . Nes, K . H . Sletten, and P . J . Warner, Appl . Environ . Microbiol . 61:4459-4463, 1995), has been cloned, and the nucleotide sequence has been elucidated . Two genes, designated plsA and plsB and encoding peptides alpha and beta, respectively, of plantaricin S, plus an open reading frame (ORF), ORF2, were found to be organized in an operon . Northern blot analysis showed that these genes are cotranscribed, giving a ca . 0.7-kb mRNA, whose transcription start point was determined by primer extension . Nucleotide sequences of plsA and plsB revealed that both genes are translated as bacteriocin precursors which include N-terminal leader sequences of the double-glycine type . The role of ORF2 is unknown at the moment, although it might be expected to encode an immunity protein of the type described for other bacteriocin operons . In addition, several other potential ORFs have been found, including some which may be responsible for the regulation of bacteriocin production . Two of them, ORF8 and ORF14, show strong homology with histidine protein kinase and response regulator genes, respectively, which have been found to be involved in the regulation of the production of other bacteriocins from lactic acid bacteria . A third ORF, ORF5, shows homology with gene agrB from Staphylococcus aureus, which is involved in the mechanism of regulation of the virulence phenotype in this species . Thus, an agr-like regulatory system for the production of plantaricin S is postulated.

Appl Environ Microbiol, 1998 May, 64(5), 1831 - 6
Cloning and characterization of a prolinase gene (pepR) from Lactobacillus rhamnosus; Varmanen P et al.; A peptidase gene expressing L-proline-beta-naphthylamide-hydrolyzing activity was cloned from a gene library of Lactobacillus rhamnosus 1/6 isolated from cheese . Peptidase-expressing activity was localized in a 1.5-kb SacI fragment . A sequence analysis of the SacI fragment revealed the presence of one complete open reading frame (ORF1) that was 903 nucleotides long . The ORF1-encoded 34.2-kDa protein exhibited 68% identity with the PepR protein from Lactobacillus helveticus . Additional sequencing revealed the presence of another open reading frame (ORF2) following pepR; this open reading frame was 459 bp long . Northern (RNA) and primer extension analyses indicated that pepR is expressed both as a monocistronic transcriptional unit and as a dicistronic transcriptional unit with ORF2 . Gene replacement was used to construct a PepR-negative strain of L . rhamnosus . PepR was shown to be the primary enzyme capable of hydrolyzing Pro-Leu in L . rhamnosus . However, the PepR-negative mutant did not differ from the wild type in its ability to grow and produce acid in milk . The cloned pepR expressed activity against dipeptides with N-terminal proline residues . Also, Met-Ala, Leu-Leu, and Leu-Gly-Gly and the chromogenic substrates L-leucine-beta-naphthylamide and L-phenylalanine-beta-naphthylamide were hydrolyzed by the PepR of L . rhamnosus.

Lett Appl Microbiol, 1998 Mar, 26(3), 231 - 5
Plantaricin D, a bacteriocin produced by Lactobacillus plantarum BFE 905 ready-to-eat salad; Franz CM et al.; Lactobacillus plantarum BFE 905 isolated from 'Waldorf' salad produced a bacteriocin termed plantaricin D which was active against Lact . sake and Listeria monocytogenes strains . Plantaricin D was heat stable, retaining activity after heating at 121 degrees C . The bacteriocin was inactivated by alpha-chymotrypsin, trypsin, pepsin and proteinase K, but not by papain and other non-proteolytic enzymes tested . Plantaricin D was stable at pH values ranging from 2.0 to 10.0 . The bacteriocin inhibited growth of L . monocytogenes in automated turbidity assays . Although Lact . Plantarum BFE 905 harboured plasmids ranging in size from 3 to 55 kilobase pairs, loss of bacteriocin production could not be correlated with plasmid loss . A role for bacteriocin-producing Lact . plantarum of vegetable origin in assuring the safety of vegetable foods is suggested.

Lett Appl Microbiol, 1998 Mar, 26(3), 209 - 14
The synergistic preservative effects of the essential oils of sweet basil (Ocimum basilicum L.) against acid-tolerant food microflora; Lachowicz KJ et al.; Essential oils extracted by hydrodistillation from five different varieties of Ocimum basilicum L . plants (Anise, Bush, Cinnamon, Dark Opal and a commercial sample of dried basil) were examined for antimicrobial activity against a wide range of foodborne Gram-positive and -negative bacteria, yeasts and moulds by an agar well diffusion method . All five essential oils of basil showed antimicrobial activity against most of the organisms tested with the exception of Flavimonas oryzihabitans and Pseudomonas species . The inhibitory effect of Anise oil, in comparison with mixtures of the predominant components of pure linalool and methyl chavicol, against the acid-tolerant organisms, Lactobacillus curvatus and Saccharomyces cerevisiae, was examined in broth by an indirect impedance method . Synergistic effects between Anise oil, low pH (pH 4.2) and salt (5% NaCl) were determined . The antimicrobial effect of Anise oil was also assessed in a tomato juice medium by direct viable count, showing that the growth of Lact . curvatus and S . cerevisiae was completely inhibited by 0.1% and 1% Anise oil, respectively . The results of the current study indicate the need for further investigations to understand the antimicrobial effects of basil oils in the presence of other food ingredients and preservation parameters.

Lett Appl Microbiol, 1998 Feb, 26(2), 153 - 4
Vancomycin susceptibility as an aid to the identification of lactobacilli; Hamilton-Miller JM et al.; Forty strains of lactobacilli isolated from probiotic supplements or functional foods, and two clinical isolates, have been identified by API 50 CHL and tested for susceptibility to vancomycin . All the Lactobacillus acidophilus (16) and Lact . delbreuckii (two) strains were sensitive to vancomycin, while all the other strains (mainly Lact . rhamnosus, 15) were resistant . Susceptibility to other antibiotics was not species-specific . Differential susceptibility to vancomycin may be helpful in speciation of lactobacilli.

Int Arch Allergy Immunol, 1998 Apr, 115(4), 278 - 87
Lactobacillus casei inhibits antigen-induced IgE secretion through regulation of cytokine production in murine splenocyte cultures; Shida K et al.; BACKGROUND: Lactobacillus casei is a nonpathogenic gram-positive bacterium widely used in dairy products and has been shown to enhance the cellular immunity of the host . METHODS: To examine the inhibitory effect of L . casei on IgE production, splenocytes obtained from ovalbumin (OVA)-primed BALB/c mice were restimulated in vitro with the same antigen in the presence of heat-killed L . casei . The effect of this bacterium on T helper (Th) phenotype development was also examined with naive T cells from OVA-specific T cell receptor-transgenic mice . RESULTS: L . casei induced IFN-gamma, but inhibited IL-4 and IL-5 secretion, and markedly suppressed total and antigen-specific IgE secretion by OVA-stimulated splenocytes . The inhibitory effect of L . casei on IgE, IL-4, and IL-5 production was partially abrogated by addition of neutralizing antibody to IFN-gamma . Augmented IL-12 production was also observed in the cell cultures containing L . casei, and anti-IL-12 monoclonal antibody completely restored the IgE, IL-4, and IL-5 production to the control levels . The IL-12 augmentation by L . casei was macrophage-dependent . The Th cell development assay showed the ability of L . casei to induce Th1 development preferentially . This effect was also completely blocked by anti-IL-12 antibody . CONCLUSIONS: This is the first demonstration that a nonpathogenic microorganism, L . casei, can inhibit antigen-induced IgE production through induction of IL-12 secretion by macrophages . The findings suggest a potential use of this organism in preventing IgE-mediated allergy.

Br J Rheumatol, 1998 Mar, 37(3), 274 - 81
Uncooked, lactobacilli-rich, vegan food and rheumatoid arthritis; Nenonen MT et al.; We tested the effects of an uncooked vegan diet, rich in lactobacilli, in rheumatoid patients randomized into diet and control groups . The intervention group experienced subjective relief of rheumatic symptoms during intervention . A return to an omnivorous diet aggravated symptoms . Half of the patients experienced adverse effects (nausea, diarrhoea) during the diet and stopped the experiment prematurely . Indicators of rheumatic disease activity did not differ statistically between groups . The positive subjective effect experienced by the patients was not discernible in the more objective measures of disease activity (Health Assessment Questionnaire, duration of morning stiffness, pain at rest and pain on movement) . However, a composite index showed a higher number of patients with 3-5 improved disease activity measures in the intervention group . Stepwise regression analysis associated a decrease in the disease activity (measured as change in the Disease Activity Score, DAS) with lactobacilli-rich and chlorophyll-rich drinks, increase in fibre intake, and no need for gold, methotrexate or steroid medication (R2=0.48, P=0.02) . The results showed that an uncooked vegan diet, rich in lactobacilli, decreased subjective symptoms of rheumatoid arthritis . Large amounts of living lactobacilli consumed daily may also have positive effects on objective measures of rheumatoid arthritis.

J Dairy Sci, 1998 Mar, 81(3), 655 - 63
The addition of oat fiber and natural alternative sweeteners in the manufacture of plain yogurt; Fernandez-Garcia E et al.; Calorie-reduced yogurts that were fortified with 1.32% oat fiber were prepared from lactose-hydrolyzed milk, alone and supplemented with 2 and 4% sucrose or with 1.6, 3.6, and 5.5% fructose . Treated samples were compared with unsweetened yogurt and with yogurts sweetened with 2, 4, and 6% sucrose . Addition of 5.5% fructose increased fermentation time by 60%, slowing down the production of lactic, pyruvic, acetic, and propionic acids and the consumption of hippuric and orotic acids . Lactose hydrolysis had an inhibitory effect on starter activity at the beginning of fermentation and a stimulatory effect at the end of fermentation . Fiber addition led to increases in concentrations of acetic and propionic acid . Lactobacilli counts were lower in samples treated with fructose . The use of hydrolyzed milk had a stimulatory effect on total bacteria and lactobacilli counts throughout the cold storage period . After 28 d of storage, lactobacilli counts were consistently higher in fiber-fortified yogurts, but total bacteria counts were lower . Apparent viscosity increased with the addition of sweetener and fiber . Lactose-hydrolyzed and fructose yogurts had the highest viscosity values . Samples sweetened with sucrose received the highest scores for flavor . Fiber addition decreased overall flavor quality . The lactose-hydrolyzed yogurts received the highest flavor scores, independent of fiber fortification . Fiber addition improved the body and texture of unsweetened yogurts but lowered overall scores for body and texture in yogurts sweetened with sucrose.

Cancer Lett, 1998 Apr 10, 126(1), 43 - 8
Cytotoxicity of heat-treated Korean mistletoe; Park JH et al.; The cytotoxic effects of preparations of Korean mistletoe (Viscum album L . var . coloratum Ohwi) on non-tumorigenic A31 cells and tumorigenic MSV cells were investigated . While the aqueous extract from Korean mistletoe (<8 microg/ml) showed strong cytotoxicity on both cell lines, the heat-treated extract was much less cytotoxic with TD50 values of above 300 microg/ml . The heat-treated extract showed a growth-enhancing effect on non-tumorigenic cells and a cytotoxic effect on tumorigenic cells . The alkaloids fraction, which was isolated from the crude extract, was not cytotoxic to non-tumorigenic A31 cells up to 550 microg/ml, but was cytotoxic to tumorigenic MSV cells at 138 microg/ml . Heat treatment did not change the cytotoxic effects of the alkaloids fraction, indicating that the selective cytotoxicity of the heat-treated mistletoe extract on tumorigenic MSV cells might be due to its alkaloids . In order to study the changes in the cytotoxicity of fermented Korean mistletoe, the crude and heat-treated extracts were inoculated with Lactobacillus plantarum . During 7 days of fermentation, the cytotoxicity of the fermented heat-treated extract was increased while that of the fermented crude extract was not changed significantly.

Int J Food Microbiol, 1998 Jan 6, 39(1-2), 123 - 8
Comparative study of lactic acid bacteria house flora isolated in different varieties of 'chorizo'; Santos EM et al.; A total of 516 strains of lactic acid bacteria isolated from 'chorizo' (a Spanish dry fermented sausage) were identified . The 'chorizo' was from three zones of Castilla and Leon in Spain: Burgos, Segovia and Salamanca . Two factories were chosen in each zone and the samples were taken at three stages of ripening . L . sake was the most predominant species present (68.8%) followed by L . curvatus (16.47%) and Pediococcus sp . (8.52%) . Different strains that do not belong to the above species were grouped as Lactobacillus sp . Group S1 comprising maltose and lactose negative L . sake was the main group present in all factories except in a factory in Segovia where group S3 comprising lactose positive L . sake and pediococci were the predominant ones . Group S1 increased during the ripening process in all six factories and it dominated in the ripened 'chorizo' except in the mentioned factory in Segovia . In general strains of L . sake and L . curvatus which fermented maltose but not lactose were more dominant at the beginning and in the middle of the process, whereas, L . sake and L . curvatus which could ferment lactose, or lactose and maltose occurred in higher numbers in semi-ripened 'chorizo' and in the final product . This indicates that strains which could ferment lactose were more competitive towards the end of the process . Strains from group S1 were the microorganisms responsible for the pH drop in most of the factories, giving the correct texture . As a result it would appear that a strain from this group would be most suitable for use as starter culture.

FEMS Microbiol Lett, 1998 Apr 1, 161(1), 97 - 106
Rapid species identification within two groups of closely related lactobacilli using PCR primers that target the 16S/23S rRNA spacer region; Berthier F et al.; A rapid and reliable PCR-based method for distinguishing closely related species within two groups of lactobacilli is described . Primers complementary to species-specific sequences in the 16S/23S rDNA spacer regions were designed after sequencing and sequence comparison of the spacer regions of 32 strains . The strains belong to two groups of closely related Lactobacillus species; one composed of Lactobacillus curvatus, Lactobacillus graminis and Lactobacillus sake, the other of Lactobacillus paraplantarum, Lactobacillus pentosus and Lactobacillus plantarum . PCR assays with the designed primers and subsequent agarose gel analysis of the amplified fragments allowed the same species identification as the DNA/DNA hybridization procedure.

Curr Microbiol, 1998 May, 36(5), 271 - 3
Evidence of a Restriction/Modification system in lactobacillus delbrueckii subsp . lactis CNRZ 326
Auad L, Peril MAA, Holgado AAPR, Raya RR.
Lactobacillus delbrueckii subsp . lactis (Lb . lactis) CNRZ 326 is widely used in the propagation of Lb . delbrueckii bacteriophages . In this study, evidence is presented that this strain possesses a restriction-modification (R/M) system . The mitomycin C-induced temperate bacteriophage lb539 has a reduced efficiency of plaquing (EOP) on CNRZ 326 cells (EOP = 10(-3)), but after several passages on this strain, or on the indicator strain Lb . lactis LKT, the recovered phages (phages lb539.326 and lb539.LKT) have an EOP equal to 1 . Restrictive development on CNRZ 326 was also observed after phage lb539.326 was propagated on the strain Lb . lactis CRL 934 . The R/M system was also active against the virulent Lb . delbrueckii phage ll-h . Plasmid DNA was not detected in CNRZ 326, which suggests that the R/M system described is chromosomally encoded.

Neth J Med, 1998 Feb, 52(2), 71 - 4
Aortic graft infection by Lactobacillus casei: a case report; Schoon Y et al.; A 65-year-old man with an abdominal aortic endoprosthesis presented with fever without other symptoms . Investigations revealed Lactobacillus casei bacteraemia . The Lactobacillus graft infection was at first successfully treated by antibiotic therapy . However, during follow-up a relapse occurred, and after surgical replacement of the graft the patient was cured . At surgery an aortoenteric fistula was found as source of the infection.

Int J Food Microbiol, 1998 Feb 17, 39(3), 175 - 83
Interaction of monolaurin, eugenol and sodium citrate on growth of common meat spoilage and pathogenic organisms; Blaszyk M et al.; Interactions of monolaurin, eugenol (phenolic compound) and sodium citrate (chelator) on the growth of six organisms including common meat spoilage (Lactobacillus curvatus, Lactobacillus sake, Leuconostoc mesenteroides, Brochothrix thermosphacta) and pathogenic (Escherichia coli O157:H7 and Listeria monocytogenes) organisms were investigated . The combinations of 100 to 250 ppm monolaurin with 500 and 1000 ppm eugenol, and 0.2 and 0.4% sodium citrate were more effective than each component separately . More than one combination prevented detectable growth of each organism . Lactic acid bacteria (LAB) and E . coli O157:H7 were most resistant and L . monocytogenes and B . thermosphacta most sensitive to control by the chosen combinations . The presence of sodium citrate was necessary to yield potent inhibition of Lb . curvatus and Lb . sake growth by the monolaurin and eugenol combinations.

Int J Antimicrob Agents, 1997 Jan, 9(3), 153 - 63
Quality assessment of glycopeptide susceptibility tests: a European collaborative study . European Glycopeptide Resistance Group; Brown DF et al.; The ability of seventy clinical laboratories in nine European countries to detect glycopeptide resistance in Gram-positive bacteria was investigated . Results of routine tests were compared with those on the same strains by a reference method in national co-ordinating laboratories . In addition, control strains were tested by some of the participants . Errors in reporting susceptibility of Staphylococcus aureus to teicoplanin and vancomycin and coagulase-negative staphylococci to vancomycin were < 1% . With coagulase-negative staphylococci however, 44 (3.4%) teicoplanin susceptible isolates were reported intermediate and six (0.4%) resistant; 18 (58.1%) of 31 teicoplanin intermediate isolates were reported susceptible and five (16.1%) resistant; and six of nine teicoplanin resistant isolates were reported susceptible and two intermediate . All seven isolates of enterococci intermediate to vancomycin were reported susceptible . Distribution of a known vancomycin intermediate strain of E . gallinarum indicated problems with vancomycin susceptibility testing (44.4% reported susceptible, 32.7% intermediate, 32.1% resistant) and identification (only 34.1% correct) of this organism . Two of 28 teicoplanin resistant enterococci and three of 30 vancomycin resistant isolates were reported susceptible . Among other organisms, one resistant Lactobacillus sp . was reported susceptible to teicoplanin and vancomycin . In reporting teicoplanin susceptible organisms, there were fewer errors with comparative/Stokes methods than with most other methods and more errors with the ATB and Sceptor methods than most other methods . None of the methods used were reliable for testing teicoplanin intermediate and resistant coagulase-negative staphylococci or low-level vancomycin resistant enterococci . Alternative methods, such as breakpoint screening, should be considered for detecting glycopeptide resistance.

Biochemistry, 1998 Mar 31, 37(13), 4535 - 42
Mode of action of site-directed irreversible folate analogue inhibitors of thymidylate synthase; Lobo AP et al.; 5,8-Dideazafolate analogues are tight binding but not irreversible inhibitors of thymidylate synthase (TS) . However, when a chloroacetyl (ClAc) group is substituted at the N10-position of 2-desamino-2-methyl-5,8-dideazafolate (DMDDF), the resulting compound, ClAc-DMDDF, although still a reversible inhibitor (KI = 3.4 x 10(-3) M), gradually inactivates thyA-TS irreversibly at a rate of 0.37 min-1 . The corresponding iodoacetyl derivative alkylated the enzyme somewhat slower (k3 = 0.15 min-1 ) than ClAc-DMDDF but was bound more tightly (KI = 1.4 x 10(-5) M), resulting in a second-order rate constant (k3/KI) of inactivation that was 100-fold greater than that of ClAc-DMDDF . A tryptic digest of the ClAc-DMDDF-inactivated enzyme yielded a peptide on HPLC, which revealed that cysteine-146, the residue at the active site that is intimately involved in the catalytic process, had reacted with ClAc-DMDDF to form a covalent bond . This derivative was confirmed indirectly by Edman analysis and more directly by mass spectrometry . Deoxyuridine 5'-monophosphate, a substrate in the catalytic reaction, protected against inactivation . Similar to previously described Lactobacillus casei TS inhibition studies with sulfhydryl reagents {Galivan, J., Noonan, J., and Maley, F . (1977) Arch . Biochem . Biophys . 184, 336-345}, the kinetics of inhibition suggested that complete inhibition occurs on reaction of only one of the two active site cysteines, although sequence and amino acid analysis revealed that iodoacetate and ClAc-DMDDF had reacted with both active site cysteines . These studies demonstrate that a sulfhydryl reactive compound that is directed to the folate binding site of TS may diffuse to the active site cysteine, and form a covalent bond with this residue . How this inhibition comes about is suggested in a stereoscopic view of the ligand when modeled to the known crystal structure of Escherichia coli TS.

J Mol Biol, 1998 Mar 20, 277(1), 119 - 34
The solution structure of the complex of Lactobacillus casei dihydrofolate reductase with methotrexate; Gargaro AR et al.; We have determined the three-dimensional solution structure of the complex of Lactobacillus casei dihydrofolate reductase (18.3 kDa, 162 amino acid residues) formed with the anticancer drug methotrexate using 2531 distance, 361 dihedral angle and 48 hydrogen bond restraints obtained from analysis of multidimensional NMR spectra . Simulated annealing calculations produced a family of 21 structures fully consistent with the constraints . The structure has four alpha-helices and eight beta-strands with two other regions, comprising residues 11 to 14 and 126 to 127, also interacting with each other in a beta-sheet manner . The methotrexate binding site is very well defined and the structure around its glutamate moiety was improved by including restraints reflecting the previously determined specific interactions between the glutamate alpha-carboxylate group with Arg57 and the gamma-carboxylate group with His28 . The overall fold of the binary complex in solution is very similar to that observed in the X-ray studies of the ternary complex of L . casei dihydrofolate reductase formed with methotrexate and NADPH (the structures of the binary and ternary complexes have a root-mean-square difference over the backbone atoms of 0.97 A) . Thus no major conformational change takes place when NADPH binds to the binary complex . In the binary complex, the loop comprising residues 9 to 23 which forms part of the active site has been shown to be in the "closed" conformation as defined by M . R . Sawaya & J . Kraut, who considered the corresponding loops in crystal structures of complexes of dihydrofolate reductases from several organisms . Thus the absence of the NADPH does not result in the "occluded" form of the loop as seen in crystal studies of some other dihydrofolate reductases in the absence of coenzyme . Some regions of the structure in the binary complex which form interaction sites for NADPH are less well defined than other regions . However, in general terms, the NADPH binding site appears to be essentially pre-formed in the binary complex . This may contribute to the tighter binding of coenzyme in the presence of methotrexate .

Appl Environ Microbiol, 1998 Apr, 64(4), 1477 - 83
Cocoa fermentations conducted with a defined microbial cocktail inoculum; Schwan RF; Cocoa fermentations were performed in wooden boxes under the following four experimental regimens: beans naturally fermented with wild microflora; aseptically prepared beans with no inoculum; and beans inoculated with a defined cocktail containing microorganisms at a suitable concentration either at zero time or by using phased additions at appropriate times . The cocktail used consisted of a yeast, Saccharomyces cerevisiae var . chevalieri, two lactic acid bacterial species, Lactobacillus lactis and Lactobacillus plantarum, and two acetic acid bacterial species, Acetobacter aceti and Gluconobacter oxydans subsp . suboxydans . The parameters measured were cell counts (for yeasts, filamentous fungi, lactic acid bacteria, acetic acid bacteria, and spore formers, including reisolation and identification of all residual cell types), sugar, ethanol, acetic acid, and lactic acid contents (and contents of other organic acids), pH, and temperature . A cut test for bean quality and a sensorial analysis of chocolate made from the beans were also performed . The natural fermentation mimicked exactly the conditions in 800-kg boxes on farms . The aseptic box remained largely free of microflora throughout the study, and no significant biochemical changes occurred . With the zero-time inoculum the fermentation was almost identical to the natural fermentation . The fermentation with the phased-addition inoculum was similar, but many changes in parameters were slower and less pronounced, which led to a slightly poorer end product . The data show that the nearly 50 common species of microorganisms found in natural fermentations can be replaced by a judicious selection and concentration of members of each physiological group . This is the first report of successful use of a defined, mixed starter culture in such a complex fermentation, and it should lead to chocolate of more reliable and better quality.

Appl Environ Microbiol, 1998 Apr, 64(4), 1466 - 71
Gene cloning, transcriptional analysis, purification, and characterization of phenolic acid decarboxylase from Bacillus subtilis; Cavin JF et al.; Bacillus subtilis displays a substrate-inducible decarboxylating activity with the following three phenolic acids: ferulic, p-coumaric, and caffeic acids . Based on DNA sequence homologies between the Bacillus pumilus ferulate decarboxylase gene (fdc) (A . Zago, G . Degrassi, and C . V . Bruschi, Appl . Environ . Microbiol . 61:4484-4486, 1995) and the Lactobacillus plantarum p-coumarate decarboxylase gene (pdc) (J.-F . Cavin, L . Barthelmebs, and C . Divies, Appl . Environ . Microbiol . 63:1939-1944, 1997), a DNA probe of about 300 nucleotides for the L . plantarum pdc gene was used to screen a B . subtilis genomic library in order to clone the corresponding gene in this bacterium . One clone was detected with this heterologous probe, and this clone exhibited phenolic acid decarboxylase (PAD) activity . The corresponding 5-kb insertion was partially sequenced and was found to contain a 528-bp open reading frame coding for a 161-amino-acid protein exhibiting 71 and 84% identity with the pdc- and fdc-encoded enzymes, respectively . The PAD gene (pad) is transcriptionally regulated by p-coumaric, ferulic, or caffeic acid; these three acids are the three substrates of PAD . The pad gene was overexpressed constitutively in Escherichia coli, and the stable purified enzyme was characterized . The difference in substrate specificity between this PAD and other PADs seems to be related to a few differences in the amino acid sequence . Therefore, this novel enzyme should facilitate identification of regions involved in catalysis and substrate specificity.

Appl Environ Microbiol, 1998 Apr, 64(4), 1359 - 65
Oxygen-dependent regulation of the expression of the catalase gene katA of Lactobacillus sakei LTH677; Hertel C et al.; The catalase gene katA of Lactobacillus sakei LTH677 was cloned and expressed in Escherichia coli UM2, Lactobacillus casei LK1, and Lactobacillus curvatus LTH1432 . The last host is a catalase-deficient plasmid-cured derivative of a starter organism used in meat fermentation . The regulation of katA expression was found to be the same in L . sakei LTH677 and the recombinant strains . The addition of H2O2 to anaerobic cultures, as well as a switch to aerobic conditions, resulted in a strong increase in KatA activity . The expression was investigated in more detail with L . sakei LTH677 and L . curvatus LTH4002 . The recombinant strain LTH4002 did not accumulate H2O2 under glucose-limited aerobic conditions and remained viable in the stationary phase . Under inductive conditions, the katA-specific mRNA and the apoenzyme were synthesized de novo . Deletion derivatives of the katA promoter were produced, and the regulatory response was investigated by fusion to the beta-glucuronidase reporter gene gusA and expression in L . sakei LTH677 . The fact that gene expression was subject to induction was confirmed at the level of transcription and protein synthesis . A small putative regulatory sequence of at least 25 bp was identified located upstream of the -35 site . Competition experiments performed with L . sakei LTH677 harboring the fusion constructs consisting of the katA promoter and gusA revealed that an activator protein is involved in the transcriptional induction of katA.

Am J Dent, 1997 Jun, 10(3), 115 - 9
2-year clinical performance of a fluoride-containing fissure sealant in young schoolchildren at caries risk; Carlsson A et al.; PURPOSE: To evaluate the clinical performance of Helioseal-F, a fluoride-containing fissure sealant, in school children at caries risk . MATERIALS AND METHODS: A caries risk assessment based on past caries experience, saliva microbial tests, buffer capacity and frequency of sugar intake was carried out in 204 healthy children, 6-7 years of age . Children exhibiting one or more risk factors were considered at caries risk (n = 121) and their permanent molars were sealed with a fluoride-containing fissure sealant, thus forming a fissure sealant group (FSG) . The remaining 83 children with low caries risk received no fissure sealants and constituted a reference group (RG) . Both groups were followed for 2 years . From 15 children of both groups, unstimulated whole saliva was collected 1 month after sealant placement in order to determine fluoride levels . In another 20 children, a split-mouth study design was utilized to compare the colonization of mutans streptococci adjacent to and on F-containing sealants and conventional controls . The sealants were placed by dental hygienists according to the manufacturers' instructions . RESULTS: A total of 431 fissure sealants were placed at baseline . Complete retention was found in 76.6% during the study period while 22.0% were partially lost . Six sealants (1.4%) were completely lost . The enamel caries incidence was 45% lower (P < 0.05) in the permanent molars of the caries risk FSG compared with the low risk RG . There was no significant increase in saliva fluoride concentration following placement of the sealants and the proportion of mutans streptococci in relation to total viable counts was unaffected by type of material . The levels of salivary mutans streptococci were mainly unchanged in both groups during the study period, while the levels of salivary lactobacilli decreased in the FSG.

Caries Res, 1998, 32(2), 100 - 6
The isolation of Actinomyces naeslundii from sound root surfaces and root carious lesions; Brailsford SR et al.; The isolation of Actinomyces naeslundii from sound, exposed root surfaces (n = 56) and soft and leathery root carious lesions (n = 71) was investigated . Root carious lesions were sampled after the removal of overlying plaque . Supragingival plaque or carious dentine was sampled using a sterile excavator, the samples were disaggregated and cultured on both selective and non-selective media . A . naeslundii isolates were identified to the genospecies using specific antisera . Significantly greater numbers and proportions of A . naeslundii genospecies 2 than A . naeslundii genospecies 1 were isolated from all sites sampled . There was no significant difference between the numbers and proportions of the two genospecies isolated from leathery and soft lesions . The relationship between the presence of A . naeslundii genospecies and aciduric and acidogenic organisms was investigated . Those sound exposed root surfaces from which A . naeslundii genospecies 1 and/or 2 were isolated yielded significantly lower numbers of lactobacilli and yeasts than the surfaces from which A . naeslundii were not isolated . This difference was also found in leathery lesions but not soft root carious lesions . The microflora of soft root carious lesions was found to comprise primarily gram-positive pleomorphic rods which formed 70+/-7.8% of the flora, while in plaque from exposed root surfaces and in infected dentine from leathery lesions the gram-positive pleomorphic rods represented only 35% of the flora.

Caries Res, 1998, 32(2), 93 - 9
Root caries and some related factors in 88-year-old carriers and non-carriers of Streptococcus sobrinus in saliva; Lundgren M et al.; The prevalence of caries on exposed root surfaces in 88-year-old subjects with and without salivary levels of Streptococcus sobrinus was studied . Ninety-two individuals were examined with regard to root caries lesions and fillings . The root caries index (RCI) was calculated and related to salivary flow rate and buffer capacity, plaque score and salivary counts of Streptococcus mutans, S . sobrinus and lactobacilli . In 89 subjects with exposed root surfaces, all but 2 harbored mutans streptococci; 51 subjects carried S . mutans only, 35 both S . sobrinus and S . mutans, and 1 S . sobrinus only . The RCI was significantly higher in persons with than those without S . sobrinus (p < 0.05) . Subjects with both S . sobrinus and S . mutans had higher counts of total mutans streptococci and lactobacilli than subjects with only S . mutans (p < 0.05) . The RCI was significantly correlated to S . sobrinus and S . mutans (p < 0.05) . The positive correlation between the RCI and S . sobrinus was still significant when the other tested variables were kept constant, whereas the correlation between the RCI and S . mutans was weaker when S . sobrinus and lactobacilli were kept constant . The D-component of the RCI (DSr%) was significantly correlated to S . sobrinus, S . mutans and lactobacilli, whereas the F-component of the RCI showed no significant correlation to any of the tested variables . A stepwise multiple correlation showed that the variance of DSr% was best explained in the S . sobrinus carriers by S . sobrinus and the salivary buffer effect, and in the non-carriers by S . mutans.

J Androl, 1998 Jan-Feb, 19(1), 37 - 49
Characterization of cysteamine as a potential contraceptive anti-HIV agent; Anderson RA Jr et al.; Cysteamine (beta-mercaptoethylamine, or MEA) is a thiol-reducing agent and has anti-HIV activity . Because of these properties, cysteamine was evaluated as a vaginal contraceptive and tested for its effects on sperm function and on other sexually transmitted microbes . Cysteamine was contraceptive in the rabbit . Conception was inhibited completely when sperm were pretreated with 500 microg/ml cysteamine and was inhibited by more than 60% when 7.5 mg cysteamine was applied vaginally as a suspension in 50% K-Y Jelly . Cysteamine had multiple effects on spermatozoa . Both acrosin (EC 3.4.21.10) and hyaluronidase (EC 3.2.1.35) were reversibly inhibited by cysteamine . Calculated IC50 values were 370 microg/ml and 150 microg/ml for acrosin and hyaluronidase, respectively . Cysteamine behaved as a poor spermicide when activity was measured by the 30-second Sander-Cramer test . However, sperm motility was inhibited completely when cysteamine was preincubated for 10 minutes prior to motility evaluation, at concentrations as low as 50 microg/ml . The calcium ionophore A23187-induced human acrosome reaction was inhibited by cysteamine (IC50 = 0.5 microg/ml) . Neither herpes simplex virus nor Neisseria gonorrhoeae was affected by cysteamine at concentrations as high as 500 microg/ml and 100 microg/ml, respectively . Cysteamine appears to have no effect on normal vaginal flora (i.e., lactobacillus) . These results, together with published data, strongly support the further development of cysteamine as a topical contraceptive anti-HIV agent.

Am J Obstet Gynecol, 1998 Mar, 178(3), 580 - 7
Few microorganisms associated with bacterial vaginosis may constitute the pathologic core: a population-based microbiologic study among 3596 pregnant women; Thorsen P et al.; OBJECTIVE: To evaluate the association between various microorganisms isolated from the genital tract in pregnant women with bacterial vaginosis . STUDY DESIGN: A cross-sectional population-based study among pregnant women addressed at their first antenatal visit before 24 full gestational weeks from the referring area of the Department of Obstetrics and Gynecology at Odense University Hospital, Denmark, from November 1992 to February 1994 . The main outcome measures were prevalence of various microorganisms and statistical estimates of interactions (crude, adjusted, and relative odds ratios) between the microorganisms isolated from the lower genital tract in pregnant women with and without clinical diagnosis of bacterial vaginosis . RESULTS: Three thousand five hundred ninety-six (3596) pregnant women were asked to participate . Of the 3596 pregnant women 3174 (88.4%) agreed to participate before 24 full gestational weeks . After controlling for the presence of other microorganisms, strong associations between Gardnerella vaginalis, anaerobic bacteria, Mycoplasma hominis, and present bacterial vaginosis were found . Similarly Lactobacillus spp . were found to be associated with the absence of bacterial vaginosis . The combination of G . vaginalis and anaerobic bacteria and/or M . hominis was found in 59.6% of the cases with bacterial vaginosis and in 3.9% of the cases without bacterial vaginosis (odds ratio 36.4, 95% confidence interval 27.8 to 47.8) . The crude odds ratio was found to be as high as 74.8 (95% confidence interval 32.3 to 174.1) when the combination of G . vaginalis, M . hominis, anaerobic bacteria, and no Lactobacillus spp . was associated with bacterial vaginosis . CONCLUSION: There is a microbial foundation for bacterial vaginosis, and it is possibly due to an intermicrobial interaction in which the microorganisms G . vaginalis, anaerobic bacteria, and M . hominis are dominating, indicating that these constitute the pathologic core of bacterial vaginosis.

Microbiology, 1998 Mar, 144 ( Pt 3), 719 - 26
The S-layer gene of Lactobacillus helveticus CNRZ 892: cloning, sequence and heterologous expression; Callegari ML et al.; Lactobacillus helveticus CNRZ 892 contains a surface layer (S-layer) composed of protein monomers of 43 kDa organized in regular arrays . The gene encoding this protein (slpH) has been cloned in Escherichia coli and sequenced . slpH consists of 440 codons and is preceded by a ribosome-binding site (RBS) and followed by a putative rho-independent terminator . Indeed, Northern analysis revealed that slpH is a monocistronic gene . The gene is preceded by a possible promotor of which the -35 and -10 hexanucleotides are separated by 17 nt . By primer extension analysis the transcription start site was mapped at 7 nt downstream of the -10 sequence while the deduced amino acid sequence of SlpH shows a leader peptide of 30 aa . The slpH gene has been amplified by PCR and the fragment, carrying the complete gene from the RBS to the stop codon, has been cloned in a lactococcal gene expression vector downstream of promoter P32 . Lactococcus lactis MG1363 carrying the resulting plasmid produced and secreted an S-layer monomer with the same molecular mass as the authentic L . helveticus CNRZ 892 SlpH, as judged by SDS-PAGE . Immunoelectron microscopy revealed that SlpH was bound to the lactococcal cell walls in small clumps and accumulated in the growth medium as small sheets.

Microbiology, 1998 Mar, 144 ( Pt 3), 705 - 17
A novel regulatory switch mediated by the FNR-like protein of Lactobacillus casei; Gostick DO et al.; FNR (regulator for fumarate and nitrate reduction) and CRP (cAMP receptor protein) are global regulators which regulate the transcription of overlapping modulons of target genes in response to anaerobiosis and carbon source in Escherichia coli . An ORF, designated flp because it encodes an FNR-like protein of the FNR-CRP family, has been found in Lactobacillus casei . The product of the flp coding region (FLP) was overproduced in E . coli, purified and crystallized . FLP is a homodimeric protein in which each subunit can form an intramolecular disulphide bond . The isolated protein also contains non-stoichiometric amounts of Cu and Zn . Although the DNA recognition helix of FLP resembles that of FNR, the flp gene failed to complement the anaerobic respiratory deficiency of an fnr mutant when expressed in E . coli and it neither activated nor interfered with transcription from FNR- or CRP-dependent promoters in E . coli . Site-specific DNA binding by oxidized FLP (the form containing intrasubunit disulphide bonds) was abolished by reduction . The interconversion between disulphide and dithiol forms thus provides the basis for a novel redox-mediated transcriptional switch . Two non-identical FLP-binding sites, distinct from FNR- and CRP-binding sites, were identified in the meIR region of E . coli by gel-retardation analysis . A further eight FLP-binding sites were selected from a random library . A synthetic oligonucleotide conforming to a putative FLP site consensus, CA/CTGA-N4-TCAG/TG (the most significant bases are underlined), was retarded by FLP . Functional tests showed that FLP represses the aerobic transcription of a semi-synthetic promoter in E . coli . A C5S variant of FLP lacking the ability to form intramolecular disulphide bonds was unable to bind to FLP sites and failed to repress transcription in vivo.

Am J Reprod Immunol, 1998 Mar, 39(3), 199 - 208
Vaginal immunization with recombinant gram-positive bacteria; Medaglini D et al.; PROBLEM: Many viral and bacterial pathogens enter the body through the genital mucosa . Therefore, one of the major goals of a vaccine against sexually transmitted diseases (STDs) should be to induce an immune response in the genital mucosa capable of controlling the entry of the pathogen . Our approach for the development of vaccines against STDs is based on the use of nonpathogenic Gram-positive bacteria as live vaccine vectors . METHOD OF STUDY: Recombinant Gram-positive bacteria expressing vaccine antigens were constructed using genetic systems developed in our laboratory . Balb/c mice and Cynomolgus monkeys were inoculated by the vaginal route and vaginal samples were collected using absorbent wicks . Colonization was evaluated by the presence of recombinant bacteria in the vaginal samples . Local and systemic immune responses were studied . RESULTS: We have developed genetic systems for the expression of heterologous antigens on the surface of the human commensals Streptococcus gordonii and Lactobacillus spp . Both S . gordonii and L . casei stably colonized the murine vagina after a single inoculum . Vaginal colonization of mice with recombinant strains of S . gordonii, expressing human papillomavirus (HPV) and human immunodeficiency virus (HIV) antigens, induced antigen-specific vaginal immunoglobulin A (IgA) and serum IgG . Local and systemic immune responses also were detected in monkeys immunized intravaginally with recombinant S . gordonii . CONCLUSION: The results obtained indicated that the approach of using colonizing Gram-positive bacteria as live vectors has a great potential for the development of vaccines against STDs.

J Acquir Immune Defic Syndr Hum Retrovirol, 1998 Apr 1, 17(4), 327 - 31
Safety study of nonoxynol-9 as a vaginal microbicide: evidence of adverse effects; Stafford MK et al.; Nonoxynol-9 (N-9) is virucidal in vitro, and is therefore a candidate microbicide for preventing sexual transmission of HIV . However, the activity of N-9 is nonspecific, suggesting that virucidal levels may produce adverse effects including epithelial disruption, inflammation of the genital mucosa, or both . A randomized placebo controlled trial of daily use of 100 mg of N-9 took place for 1 week in 40 female volunteers . Outcome measures included symptoms, colposcopic and histologic changes in the genital tract, and impact on vaginal flora . Genital irritation was reported by 10 of the N-9 and 5 of the placebo group . Colposcopy showed erythema in 9 of the N-9 group and 2 of the placebo group . Histologic inflammation was found in 7 of the N-9 group and 2 of the placebo group . Inflammatory changes were characterized by patchy infiltration of the lamina propria predominantly with CD8+ lymphocytes and macrophages, in the absence of epithelial disruption . A transient reduction in numbers of lactobacilli was observed in 9 of the 15 women using N-9, and 6 of 18 women using placebo . N-9 used for 7 days in a standard spermicidal dose was associated with increased irritation, colposcopic and histologic evidence of inflammation and was more frequently associated with reduction in numbers of lactobacilli during gel use . The clinical significance of the recruitment of cells susceptible to HIV infection to the genital mucosa is unknown but raises concerns about the suitability of N-9 as a microbicide when given in this dosePIP: Since nonoxynol-9 (N-9) is virucidal in vitro, it is a candidate microbicide for preventing the sexual transmission of HIV . A randomized placebo-controlled trial of the daily use of 100 mg of N-9 was conducted for 1 week among 40 female volunteers aged 18-45 years . Genital irritation was reported by 10 of the N-9 users and 5 women in the placebo group . Colposcopy showed erythema in 9 of the N-9 group and 2 of the placebo group . Histologic inflammation was found in 7 of the N-9 group and 2 of the placebo group . Inflammatory changes in the women were characterized by patchy infiltration of the lamina propria mainly with CD8 lymphocytes and macrophages, in the absence of epithelial disruption . A transient reduction in the number of lactobacilli was observed in 9 of the 15 women using N-9, and 6 of the 18 women using placebo . N-9 used for 7 days in this standard spermicidal dose in the absence of sexual intercourse was therefore associated with increased irritation, colposcopic and histologic evidence of inflammation, and was more often associated with a reduction in the numbers of lactobacilli during gel use . The clinical significance of the recruitment of cells susceptible to HIV infection to the genital mucosa remains to be determined .

J Biochem Mol Toxicol, 1998, 12(3), 167 - 73
Thymidylate synthase activity and the cell growth are inhibited by the beta-carboline-benzoquinolizidine alkaloid deoxytubulosine; Rao KN et al.; Employing thymidylate synthase (TS) (5, 10-CH2-H4PteGlu: dUMP C-methyltransferase, EC 2.1.1.45), a key target enzyme in chemotherapy, the biological activity of the beta-carboline-benzoquinolizidine alkaloid deoxytubulosine (DTB) isolated from the Indian medicinal plant Alangium lamarckii has been evaluated and assessed for the first time . The TS employed in the present studies was purified from Lactobacillus leichmannii . The DTB was demonstrated to exhibit potent cytotoxicity and inhibited the cell growth of L . leichmannii, and DTB potently inhibited TS activity (IC50 = 40 microM) . The DTB concentrations > 80 microM resulted in a total loss of the TS activity, thus suggesting that the beta-carboline-benzoquinolizidine alkaloid is a promising potential antitumor agent . The DTB binding to TS appears to be irreversible and tight through a possible covalent linkage . Although DTB strongly binds to DNA, it is not known whether DTB binds to RNA associated with TS . Inhibition kinetics showed that TS has a Ki value of 7 x 10(-6) M for DTB and that the inhibition is a simple linear "noncompetitive" type.

J Indian Soc Pedod Prev Dent, 1994 Mar, 12(1), 17 - 20
Study of microflora in well-nourished and mal-nourished children in relation to dental caries; Chopra S et al.; Forty-five children in the age group of 2-12 years comprising 20 well-nourished (W.N.), 20 malnourished (M.N.) (both groups having DMFS of > or = 5) and 5 caries free well nourished children (control group) were studied to find out the oral microflora in these groups S . mutans was present in 55%, 20% and 0% in W.N., M.N., and control groups while S . Salivarius was isolated in 45%, 80% and 40% in the three groups respectively . There was no significant difference in the prevalence of Lactobacillus and C . albicans in the three groups . The correlation between means DMFS and the prevalence of S . mutans in W.N . and M.N . groups was highly significant (P < 0.001) . Nutritional status including different grades of malnutrition had no significant bearing on the prevalence of micro-organisms isolated . The caries prevalence was higher in the W.N . group (P) while the gingival index was higher in M.N . group.

J Dent Assoc S Afr, 1993 Apr, 48(4), 177 - 81
Oral lactobacilli isolated from teenage orthodontic patients; Botha SJ; Orthodontic bands form retention areas which create favourable conditions for growth of lactobacilli . This study deals with the numbers and specific species of lactobacilli in the oral cavity of teenage orthodontic patients . High numbers of lactobacilli were obtained (log 6.398 +/- 0.761 cfu/ml) and the buffer capacity of saliva indicated a high caries risk amongst these individuals but the actual DMFT values were relatively low . Homofermentative lactobacilli predominated in both plaque and saliva and particularly L . salivarius and L . casei . These two lactobacilli species indicated that these patients are at a high caries risk . Several other homofermentative and heterofermentative lactobacilli were isolated which indicated the complexity of the oral lactobacilli community in saliva and plaque.

Mikrobiol Z, 1997 Nov-Dec, 59(6), 36 - 43
{The adhesive properties of bacteria in the genus Bacillus--the components of a probiotic}; Smirnov VV et al.; The adhesive properties of bacteria of the genus Bacillus as the components of biopreparation for gynecological practice have been studied using erythrocytes as a model of the macroorganism cells . The average level of adhesion of the Bacillus genus bacteria has been established . High degree of adhesion has been manifested only by the strains of bacteria of the Lactobacillus genus, being promising for the creation of biopreparation . Study of the effect of conditionally pathogenic microorganisms on adhesive properties of bacteria of the Bacillus genus has demonstrated the absence of changes in the level of adhesion of bacilli in 48% of mixed populations.

Oral Oncol, 1997 Nov, 33(6), 439 - 43
Five-year follow-up study of saliva, mutans streptococci, lactobacilli and yeast counts in lymphoma patients; Meurman JH et al.; Twenty-two patients out of the 79 that were originally included were examined 5 years after beginning anticancer therapy for lymphomas . The patients' cumulative data on salivary flow rate, buffering capacity and acidogenic microbial counts were compared with respective data of 17 patients who died during the follow-up . Stimulated saliva samples had been taken at baseline and during the cytostatic treatment with combination chemotherapy, and 1 year and 5 years later . Chair-side kits were used at the hospital ward for the assessment of the study parameters . Mean saliva flow at baseline was 1.5 +/- 0.7 ml/min in the surviving group and 1.5 +/- 0.8 ml/min in the deceased . Salivary flow rates were not affected by the anticancer treatment and there was no statistically significant difference between the groups in this respect . A significant difference was observed between the groups in salivary buffering capacity values at baseline: only 32% of the survived had low buffering capacity in comparison to 69% of those who later died (P < 0.02) . Buffering capacity values remained low in 50% of the surviving patients 5 years later . Higher mutans streptococci and lactobacilli counts were seen among the deceased than in the survived patients but mutans streptococci decreased significantly in both groups after the start of the anticancer therapy (P < 0.05) . The number of positive yeast counts increased consistently during the chemotherapy in both groups, being higher in the survived when compared with the deceased patients . Yeast counts remained positive 5 years later in 73% of the survived patients, while the mean mutans streptococci and lactobacilli counts decreased below baseline values . The results showed that persistently high salivary microbial counts and low buffering capacity may be linked with poor prognosis.

FEMS Microbiol Lett, 1998 Feb 15, 159(2), 293 - 7
Poly-beta-hydroxybutyrate production by lactic acid bacteria; Aslim B et al.; Poly-beta-hydroxybutyrate was determined in lactic acid bacteria belonging to the genera Lactobacillus, Lactococcus, Pediococcus and Streptococcus . Lactobacilli were grown in MRS broth, the others were grown in Elliker broth medium . Cell biomass was obtained by centrifugation . The cell walls were lysed with sodium hypochlorite . Poly-beta-hydroxybutyrate was extracted using chloroform in a Soxhlet system . Then it was converted to crotonic acid using sulfuric acid and the amount of crotonic acid was measured spectrophotometrically . The yield of poly-beta-hydroxybutyrate (% of cell dry weight) of Lactobacillus species was 6.6-35.8% . The values for Lactococcus, Pediococcus and Streptococcus species were 9.0-20.9, 1.1-8.0 and 6.8-17.2, respectively . It was observed that one of the Lactobacillus species did not produce poly-beta-hydroxybutyrate . Generally, Lactobacillus species produced more poly-beta-hydroxybutyrate than the other tested bacteria and no significant correlation was observed between poly-beta-hydroxybutyrate production and cell density of the cultures.

FEMS Microbiol Lett, 1998 Feb 15, 159(2), 221 - 5
Analysis of hopanoids in bacteria involved in food technology and food contamination; Kuchta T et al.; Hopanoids are pentacyclic triterpenoids which are believed to act as reinforcers of membranes in certain prokaryotic microorganisms . A rapid and sensitive method for their screening in bacteria was elaborated, involving extraction of nonsaponifiable lipids and the analysis by gas chromatography-mass spectrometry, selectively monitoring the ion of m/z = 191 . Using the method, hopanoids were detected in strains of Acetobacter pasteurianus, but were found to be absent in lactic acid bacteria (Lactobacillus spp., Lactococcus spp.) and in food-contaminating bacteria (Salmonella spp., Listeria spp., Yersinia spp . and others).

Nutr Health, 1998, 12(2), 97 - 105
Probiotic fermented food mixtures: possible applications in clinical anti-diarrhoea usage; Rani B et al.; A probiotic fermented PCMT food mixture was developed by fermentation of an autoclaved and cooled slurry of pearl millet flour, chickpea flour, skim milk powder and fresh tomato pulp (PCMT 2:1:1:1, w/w) with Lactobacillus acidophilus (10(5) cells/ml), a probiotic organism at 37 degrees C for 24 h . Such a fermented mixture inhibited the growth of pathogenic organisms, namely Shigella dysenteriae, Salmonella typhosa and E . coli . A significant decline in pH with a corresponding increase in titratable acidity due to probiotic fermentation occurred in the developed food mixture . Feeding of the freshly developed fermented mixture to mice suffering from E . coli induced diarrhoea, could help to arrest diarrhoea, reduce moisture, protein and ash contents in their faeces . The counts of lactobacilli increased whereas those of E . coli decreased remarkably in the faeces of mice from the 3rd day of the feeding trial till the end of experimental period . The beneficial effect of probiotic feeding may be due to antimicrobial substances produced by L . acidophilus, which might have neutralized the enterotoxins from E . coli . The cost of one 200 ml glass full of this probiotic drink is no more than one rupee.

Am J Obstet Gynecol, 1998 Feb, 178(2), 374 - 80
Epidemiology and outcomes associated with moderate to heavy Candida colonization during pregnancy . Vaginal Infections and Prematurity Study Group; Cotch MF et al.; OBJECTIVE: Our purpose was to determine the risk factors, physical findings, microflora, and pregnancy outcome among pregnant women with moderate to heavy vaginal growth of Candida albicans and other Candida species . STUDY DESIGN: A multicenter cohort of 13,914 women were enrolled between 23 and 26 weeks' gestation . Women completed a questionnaire, underwent a physical examination, and had genital specimens taken for culture . A subset of 1459 women were reexamined during the third trimester . Pregnancy outcomes were recorded at delivery . RESULTS: The prevalence of moderate to heavy Candida colonization at midgestation was 10% . Colonized women, 83% of whom carried C . albicans, were more likely to be black or Hispanic, unmarried, a previous oral contraceptive user, and to manifest clinical signs indicative of Candida carriage . Candida colonization was positively associated with Trichomonas vaginalis, group B streptococci, and aerobic Lactobacillus and was not associated with adverse pregnancy outcome . CONCLUSION: These results suggest that Candida colonization is not associated with low birth weight or preterm delivery.

Int J Food Microbiol, 1997 Sep 16, 38(2-3), 125 - 31
Autolysis of Lactococcus lactis ssp . lactis and Lactobacillus casei ssp . casei . Cell lysis induced by a crude bacteriocin; Martinez-Cuesta MC et al.; Autolytic properties of Lactococcus lactis subsp . lactis IFPL359, its Lac Prt derivative Lc . lactis Tl and Lactobacillus casei subsp . casei IFPL731, used as starter and adjunct starter in goat's milk cheese making, have been studied . The lytic effect of a bacteriocin produced by a lactic acid bacterium isolated from raw goat's milk has also been analyzed . Lactococcal cells resuspended in phosphate buffer showed a peak of autolysis when they were harvested in the early growth phase . A more stable autolytic pattern through the exponential growth was obtained for Lb . casei IFPL731 . Optimal autolysis was found in 0.1 M sodium phosphate buffer during incubation at 40 degrees C for Lb . casei IFPL731 and at 35 degrees C for the lactococci . Thermoinduction of cell lysis was not obtained in any of the cases under the conditions studied . Lytic effect of the crude bacteriocin assayed was strongest against Lc . lactis Tl . Lysis response to the bacteriocin seemed to be strain-dependent and related to growth conditions.

Int J Food Microbiol, 1997 Sep 16, 38(2-3), 117 - 23
Ropy slime-producing Lactobacillus sake strains possess a strong competitive ability against a commercial biopreservative; Bjorkroth J et al.; Aseptically handled Frankfurters were treated with a commercial Lactobacillus alimentarius biopreservative and inoculated with different cell concentrations of four ropy slime-producing Lactobacillus sake strains . The packages were vacuum sealed and kept at 6 degrees C for 28 days, after which the production of ropy slime was evaluated . The inoculation test was controlled by sealing the different control packages containing either aseptically manufactured sausages without any bacterial inoculation, packages containing biopreservative only or packages inoculated only with the four different ropy slime-producing strains . Authenticity of the biopreservative strain after the cold storage period was ascertained by performing EcoRI restriction endonuclease analysis of 30 randomly selected isolates originating from the biopreservative control packages . All patterns were identical to the pattern of the original L . alimentarius biopreservative strain . The biopreservative was found to be ineffective against the four ropy slime-producing L . sake strains . The strongest slime producers inoculated with approximately 1 colony forming units (CFU)/cm2 could compete efficiently with the L . alimentarius inoculated at a level of 10(7) CFU/cm2 on sausage surfaces . This commercial biopreservative failed to occupy the vital niche of the four ropy slime-producing L . sake strains leading to spoilage in almost all packages.

Egypt Dent J, 1995 Apr, 41(2), 1179 - 88
Assessment of salivary Lactobacillus and Streptococcus mutans counts following sodium fluoride mouthrinsing in Egyptian children; Waly NG; The salivary Lactobacillus and Streptococcus mutans counts were assessed in 100 Egyptian children, initially before mouthrinsing with 0.05% sodium fluoride solution, 24 hours and 48 hours following rinsing . A statistically significant reduction in Lactobacillus and Streptococcus mutans counts of 49% and 44% respectively was obtained 24 hours following rinsing . This percentage decrease in both bacterial counts was reduced to 27% and 31% respectively, 48 hours following rinsing.

Periodontal Clin Investig, 1997 Fall, 19(2), 17 - 21
Effect of an enzymatic rinse on salivary levels of Streptococcus mutans and lactobacilli in periodontally treated patients; Lehane RJ et al.; Root surface caries is prevalent in patients with both treated and untreated periodontal disease . The major etiologic factor has been identified as microbial plaque . In periodontally treated patients, significantly higher root caries prevalence and incidence have been found in patients with high levels of Streptococcus mutans and Lactobacilli in saliva . Reducing the levels of S . mutans and Lactobacilli in saliva may lower the risk of root caries development . The purpose of this investigation was to determine the effect of an oral enzymatic rinse on the salivary counts of S . mutans and Lactobacilli in periodontally treated patients . Fifteen adult subjects participated in a double-blind, cross-over designed clinical trial . Each subject had previously undergone comprehensive periodontal therapy and had been maintained on a regular program of supportive periodontal therapy . Paraffin-stimulated whole saliva was collected from each participant . Each subject was then randomly given either the enzymatic rinse product or a control rinse and instructed to rinse with one tablespoonful twice a day for 2 weeks, after which saliva samples were taken . After a washout period, salivary samples were again taken, and the subjects received the alternate rinse product . Two weeks later, final salivary samples were taken . The salivary samples were serially diluted and incubated aerobically on selective culture media . S . mutans and Lactobacilli were counted on the basis of colonial morphology . Pretreatment and posttreatment salivary counts of S . mutans and Lactobacilli were analyzed using the Wilcoxon matched-pairs signed-rank test at the 5% level of significance . Analysis of data revealed that neither the test nor the control rinse significantly lowered salivary counts of either species in the sample population.

J Dairy Sci, 1998 Jan, 81(1), 48 - 53
The effect of oral feeding of Lactobacillus casei strain Shirota on immunoglobulin E production in mice; Matsuzaki T et al.; We investigated the effect of oral feeding of heat-killed Lactobacillus casei strain Shirota on immunoglobulin E (IgE) production in mice . The strain was orally administered to BALB/c mice that had been preinjected intraperitoneally with ovalbumin, and the level of IgE in serum was determined . Results indicated that the oral feeding of L . casei strain Shirota was effective in inhibiting IgE production in serum, and the IgE production in response to ovalbumin was significantly inhibited in the mice . The in vitro production of IgE by the spleen cells from mice fed L . casei strain Shirota in response to restimulation with ovalbumin was inhibited in contrast to that of spleen cells from the control group . We also examined the pattern of cytokine production by spleen cells from mice fed L . casei strain Shirota followed by restimulation with ovalbumin in vitro . In the mice fed L . casei strain Shirota, the production by the spleen cells of Th1 cell-associated cytokines, such as interferon-gamma and interleukin-2, was higher than that by the spleen cells from the control group . In contrast, the production of Th2 cell-associated cytokines, such as interleukin-4, interleukin-5, interleukin-6, and interleukin-10, by spleen cells in the group fed L . casei strain Shirota was lower than that by the cells from the control group . Furthermore, the interleukin-12 production of the spleen cells from mice fed L . casei strain Shirota was also higher than that of the control group.

Northwest Dent, 1996 Jul-Aug, 75(4), 23 - 5
The agar-replica technique for dental caries diagnosis . Has its time arrived?
Adams AB, Jones DA.
The agar-replica technique of Bahn et al is described . This caries-diagnostic technique detects the site of lactobacillus infection on the teeth . Evidence and logic indicate that this technique is more accurate than current caries-diagnostic methods . The method appears to answer the recent call for diagnostic methods which identify the more subtle expression of the disease, and it helps classify lesions into categories keyed to different treatment strategies.

J Anim Sci, 1998 Jan, 76(1), 299 - 308
A review of bloat in feedlot cattle; Cheng KJ et al.; Improvements in feedlot management practices and the use of various feed additives have reduced, but not eliminated, the occurrence of bloat in feedlot cattle . Feedlot bloat reduces the profitability of production by compromising animal performance and more directly by causing fatalities . In feedlots, bloat is associated with the ingestion of large amounts of rapidly fermented cereal grain and destabilization of the microbial populations of the rumen . An abundance of rapidly fermented carbohydrate allows acid-tolerant bacteria (e.g., Streptococcus bovis and Lactobacillus spp.) to proliferate and produce excessive quantities of fermentation acids . As a result, ruminal pH becomes exceedingly low, and this impairs rumen motility . Further, the excessive production of mucopolysaccharide or "slime" increases the viscosity of ruminal fluid and stabilizes the foam implicated in frothy feedlot bloat . Although protocols have been developed to treat feedlot bloat, the most profitable approach is to use management strategies to reduce its likelihood . Amount of roughage, grain processing techniques, selection of cereal grain (e.g., corn, barley, and wheat), dietary adaptation periods, and various additives (e.g., ionophores) can influence the occurrence of bloat in feedlot cattle . Successful management of these factors depends on a thorough understanding of the behavioral, dietary, and microbial events that precipitate bloat in feedlot cattle.

J Anim Sci, 1998 Jan, 76(1), 234 - 41
Ruminal microbial and fermentative changes associated with experimentally induced subacute acidosis in steers; Goad DW et al.; We used six ruminally cannulated steers in a two-period crossover design to study ruminal fermentative and microbial changes associated with induced subacute acidosis . Steers were adapted to either an 80% alfalfa hay (hay-adapted)- or corn grain (grain-adapted)-based concentrate diet . After feed was withheld for 24 h, steers were overfed with an all-grain diet at 3.5 x NEm daily for 3 d . Ruminal contents and jugular blood samples were collected before withholding feed and at 0 and 12 h daily for 3 d during the overfeeding period . Ruminal samples were analyzed for pH, lactate, VFA concentrations, and counts of total anaerobic, amylolytic, lactic acid-producing and -fermenting bacteria, and ciliated protozoa . Blood samples were analyzed to assess acid-base status . Ruminal pH declined to a range of 5.5 to 5.0 with increased VFA concentrations, but normal lactate concentrations (<5 mM) were indicative of subacute acidosis . Total viable and amylolytic bacterial counts were higher (P < .05) in grain-adapted than hay-adapted steers . Anaerobic lactobacilli counts increased over time (P < .01) in both groups and were generally higher in grain-adapted than hay-adapted steers . Lactate-utilizing bacteria were initially greater in grain-adapted than hay-adapted steers and increased over time in both groups following grain challenge . Total ciliates were initially higher (P < .05) in grain-adapted than hay-adapted steers and decreased after 48 h in both groups . Blood acid-base changes were minimal . Bacterial changes associated with subacute acidosis resemble those reported during adaptation to grain feeding, and the decline in ciliated protozoa may be the only microbial indicator of a potentially acidotic condition in the rumen.

Appl Environ Microbiol, 1998 Feb, 64(2), 659 - 64
Optimization of exopolysaccharide production by Lactobacillus delbrueckii subsp . bulgaricus RR grown in a semidefined medium; Kimmel SA et al.; The optimal fermentation temperature, pH, and Bacto-casitone (Difco Laboratories, Detroit, Mich.) concentration for production of exopolysaccharide by Lactobacillus delbrueckii subsp . bulgaricus RR in a semidefined medium were determined by using response surface methods . The design consisted of 20 experiments, 15 unique combinations, and five replications . All fermentations were conducted in a fermentor with a 2.5-liter working volume and were terminated when 90% of the glucose in the medium had been consumed . The population of L . delbrueckii subsp . bulgaricus RR and exopolysaccharide content were measured at the end of each fermentation . The optimum temperature, pH, and Bacto-casitone concentration for exopolysaccharide production were 38 degrees C, 5, and 30 g/liter, respectively, with a predicted yield of 295 mg of exopolysaccharide/liter . The actual yield under these conditions was 354 mg of exopolysaccharide/liter, which was within the 95% confidence interval (217 to 374 mg of exopolysaccharide/liter) . An additional experiment conducted under optimum conditions showed that exopolysaccharide production was growth associated, with a specific production at the endpoint of 101.4 mg/g of dry cells . Finally, to obtain material for further characterization, a 100-liter fermentation was conducted under optimum conditions . Twenty-nine grams of exopolysaccharide was isolated from centrifuged, ultrafiltered fermentation broth by ethanol precipitation.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 1997 Dec, 84(6), 624 - 9
The association of yeasts and denture stomatitis with behavioral and biologic factors; Sakki TK et al.; OBJECTIVES: This study describes the association of yeasts and denture stomatitis with behavioral and biologic factors . STUDY DESIGN: Seven hundred eighty 55-year-old citizens of Oulu, Finland, were examined clinically; 452 of them had complete dentures . Salivary yeasts and lactobacillus counts were detected through the use of Oricult-N and Dentocult-LB dip-slide techniques . Lifestyle factors were measured by means of questions concerning physical activity, tobacco smoking, alcohol consumption, and dietary habits . Other background variables used in cross-tabulations and logistic regression analysis were unstimulated salivary secretion rate, retention of denture, oral hygiene, gender, and socioeconomic status . RESULTS: The prevalence of denture stomatitis was greater among subjects with an unhealthy lifestyle, subjects with higher lactobacillus counts, and subjects with poor oral hygiene . Salivary secretion rate and smoking were associated with the presence of yeasts, but general lifestyle measures were not . CONCLUSION: The presence of yeasts tended to be associated with biologic factors, but behavioral factors reflecting lifestyle may be more important in the development of denture stomatitis.

Chem Biol, 1995 Sep, 2(9), 609 - 14
Role of the conserved tryptophan 82 of Lactobacillus casei thymidylate synthase; Kealey JT et al.; BACKGROUND: Thymidylate synthase (TS; EC 2.1.1.45) catalyzes the reductive methylation of 2'-deoxyuridine-5'-monophosphate (dUMP) by 5,10-methylene-5,6,7,8-tetrahydrofolate (CH2H4folate) to produce 2'-deoxythymidine-5'-monophosphate (dTMP) and 7,8-dihydrofolate (H2folate) . Major advances in the understanding of the mechanism of TS have been made by studying site-specific mutants of the enzyme . Trp82 is completely conserved in all of the 20 TS sequences known . It forms part of the CH2H4folate binding pocket, is reported to be a component of a catalytically important H-bond network, and is suspected to be the source of an unusual absorbance change at 330 nm when TS forms a ternary complex with 5-fluoro-dTMP and CH2H4folate . We therefore prepared and characterized a set of 12 mutants at position 82 of Lactobacillus casei TS . RESULTS: Eight Trp82 mutants were active enough for us to determine their kinetic constants for dTMP production, while four were inactive . The active mutants had higher Km values for dUMP (2- to 10-fold) and CH2H4folate (2- to 27-fold), and lower kcat values (12- to 250-fold) than wild-type TS . The most active mutants were those containing the aromatic side chains Phe and His at position 82 . All of the Trp82 mutants catalyzed the debromination of 5-bromo-dUMP with kinetic parameters similar to those of wild-type TS, and all formed ternary complexes with 5-fluoro-dUMP and CH2H4folate . The absence of Trp82 did not prevent the absorbance change at 330 nm on ternary complex formation . CONCLUSIONS: Trp82, a completely conserved residue that was shown by X-ray crystallography to interact directly with CH2H4folate and indirectly with dUMP, does not appear to be essential for binding or catalysis . We do, however, find a preference for an aromatic side chain at position 82 . Trp82 does not contribute to the unique spectral change at 330 nm that accompanies TS ternary complex formation.

Mol Microbiol, 1997 Oct, 26(2), 347 - 60
Pheromone-induced production of antimicrobial peptides in Lactobacillus; Brurberg MB et al.; Production of the bacteriocin sakacin P by Lactobacillus sake LTH673 is dependent on a secreted 19-residue peptide pheromone (IP-673) . The gene encoding IP-673 (sppIP) was identified and sequenced . SppIP was shown to be co-transcribed with genes encoding a histidine kinase (sppK) and a response regulator (sppR) typical for signal transduction in bacteria . Further sequencing and transcription studies have shown that IP-673 induces transcription of its own gene and of what are often considered to be all genes necessary for bacteriocin production and immunity . Studies with a reporter gene showed that the promoter in front of the sakacin P structural gene (sppA) is strictly regulated . The promoter in front of sppIP turned out to be less strictly regulated, and low basal promoter activity could be detected in uninduced cells . Bacteriocin production in Bac isolates of L . plantarum C11 could be induced by the non-cognate IP-673 only after the introduction of sppK, indicating that sppK encodes the pheromone receptor . These results show that bacteriocin production in lactobacilli is regulated using a short, strain-specific peptide pheromone . Growth conditions were shown to have considerable effects on the functionality of this regulatory mechanism.

Zh Mikrobiol Epidemiol Immunobiol, 1995 Jul-Aug, (4), 19 - 23
{The traditional classification and genetic systematics of bacteria in the genus Lactobacillus}; Blokhina IN et al.; The classification of bacteria of the genus Lactobacillus has virtually been constructed according to generally accepted peculiarities of the carbohydrate metabolism of the 3 selective groups . The information about the nucleotide contents of DNA (%GC) allows to divide all of 67 species included in the genus into 4 "nucleotide" group according to genosystematics principles . The first group species has %GC = first--49-53, second--42-46, third--34-41 and fourth--32-37 . In this manner, it will be singled out 4 new genera in a new proposed family Lactobacillaceae comb.nov.: Thermobacterium comb.nov., Streptobacterium comb.nov., Mediumbacterium comb.nov., and Betabacterium comb.nov . correspondingly . For further revision of the systematics of the bacteria of the Lactobacillaceae family comb.nov . in the direction of approaching its to the natural one it is essential to study of the degree of genome similarities of species representatives within being outline 4 "nucleotide" group both the molecular hybridization using the specific DNA probes and the restriction analysis of the chromosomal DNA (dactyloscopy genome technique).

Mol Cell Probes, 1997 Oct, 11(5), 317 - 22
Detection of erythromycin resistant methylase gene by the polymerase chain reaction; Nawaz MS et al.; A polymerase chain reaction (PCR) protocol was developed that could specifically amplify a 520-bp region of the erythromycin resistant methylase (ermC) gene sequence . The identity of the PCR-amplified 520-bp DNA was confirmed by HinCII endonuclease restriction digestion, which produced the predicted 440-bp and 80-bp DNA fragments . A 20-mer (alpha-32P) oligonucleotide probe specifically hybridized with these amplified products confirming the specificity and reliability of this diagnostic assay . The assay could detect the ermC gene in bacterial suspensions containing as few as 10(3) cells ml-1 . The assay was used to detect the presence of the ermC gene in several Gram-positive bacterial strains identified as Streptococcus sp., Staphylococcus sp., Micrococcus sp., Lactobacillus sp . and Enterococcus sp., isolated from water samples maintained in experimental animal cages and clinical sources . Only bacteria identified as Staphylococcus sp . were resistant to the antibiotic . Although 17 strains of Staphylococcus sp . isolated from clinical samples were resistant to erythromycin, only seven of these isolates tested positive for the presence of the ermC gene . Of these strains, five were identified as coagulase-positive S . aureus and the rest were identified as coagulase-negative S . epidermidis . The erythromycin resistance in all seven ermC positive isolates was constitutive . The entire diagnostic assay, including template preparation, amplification and electrophoresis can be completed within 6 h.

Rev Med Chir Soc Med Nat Iasi, 1996 Jul-Dec, 100(3-4), 198 - 202
Clinical and therapeutical aspects of rampant caries in cervico-facial irradiated patients; Lacatusu S et al.; The irradiant cervico-facial therapy produces numerous complications in maxillo-facial territory, among which the most frequent are: xerostomia, osteonecrosis, mucosal degeneration and severe rampant caries . This is the reason why a written report must exist between the dentist and the radiologist, with all data of the radiological treatment, which implies the patient follow-up from a stomatologic point of view before, during and after the application of the irradiate treatment . We studied a group of patients that followed an X-ray treatment, determining the salivary flow, the physical and chemical feature of the saliva and bacterial flora before, during the X-ray treatment with different doses and at the end of the treatment and at certain periods of time . The rampant caries were found in 46% of cases and interested the cervical zones, the incisal edges and the cusps, zones that are usually resisting at caries . The irradiation produced an important decrease of the repose and activated salivary flow (under 0.1 mL/min), of the buffering capacity of saliva . Also, the saliva became more viscous and the total quantity of proteins increased . The microbial flora is modified with the increasing level of Streptococcus mutans and Lactobacillus . In 23% of patients the secretion returned to normal at 3 weeks from the irradiation, at the other it was irreversible, as a result of a radiation-induced damage to the salivary glands (the atrophy through the increasing of radiant dose) . The treatment was different, depending on the clinical condition of the patient and the disease prognosis . It is recommended the compulsory use of the prophylactic treatment . The authors suggest their treatment planning that includes the reduction of the microbial flora, the change of alimentary diet and salivary stimulates or substitutes . These prevent the appearing of rampant caries that will require ample restorations.

Gerodontology, 1996 Jul, 13(1), 35 - 43
Whole saliva and the diagnosis of Sjögren's syndrome: an evaluation of patients who complain of dry mouth and dry eyes . Part 1: Screening tests; Sreebny L et al.; Sjogren's syndrome (SS) is a common autoimmune disorder characterised by generalised desiccation, exocrine hypofunction and serologic abnormalities, More than 90% of the patients are women . OBJECTIVE: To determine if whole saliva could be used to diagnose this disease . SETTING: The study was conducted at the School of Dental Medicine, SUNY, at Stony Brook . PATIENTS: There were 49 subjects (48 F; 1 M), the mean age was 54 +/- 13 years . In order to be admitted into the study, they had to complain of dry mouth and dry eyes . TESTS: Whole saliva was collected by the spitting method . "Screening Tests" were employed to measure the salivary flow rate, pH, buffer capacity; lactobacillus and yeast concentrations . Chemical tests were performed to determine protein, albumin, sodium and amylase activity . Lacrimal dryness was assessed by the Schirmer and Rose-Bengal methods . RESULTS: Based on the sialometric findings, the patients were divided into 3 groups: Group 1: those with abnormally low resting (RFR) and stimulated (SFR) flow rates; Group 2: those with a low RFR but normal SFR; and Group 3: those with normal salivary flow rates . The group 1 patients were unique: their saliva demonstrated a low pH and buffer capacity, high lactobacillus and yeast concentrations, decreased protein output and amylase activity, and elevated albumin and sodium . Moreover, virtually all of them had abnormally low lacrimal flow rates . CONCLUSIONS: The findings suggested that whole saliva could be used to provisionally diagnose SS . Critical to this diagnosis was an abnormally low stimulated whole saliva flow rate . Other requisites included a low resting flow rate, the presence of dry mouth and dry eyes and evidence of lacrimal hypofunction . All of these attributes can easily be obtained by dentists in their clinics.

Berl Munch Tierarztl Wochenschr, 1997 Dec, 110(11-12), 413 - 7
In vitro studies of porcine lactobacilli for possible probiotic use; Nemcova R et al.; Fourteen strains of lactobacilli isolated from the gut of suckling pigs were identified and studied to determine their susceptibility to antimicrobial feed additives, acid tolerance, adherence to epithelial cells from the porcine intestine and antimicrobial activity . Four strains were identified as Lactobacillus casei subsp . casei, two strains as Lactobacillus rhamnosus as well as Lactobacillus reuteri and three strains as Lactobacillus salivarius . The remaining strains could not be identified . Antimicrobial susceptibility tests showed susceptibility of the lactobacilli to many of the antimicrobial feed additives commonly used in pigs . Strains resistant to cyadox and nourseothricin occurred in high numbers . The tested lactobacilli were acid-resistant at pH 3 . Thirteen strains of lactobacilli exhibited strong adherence to epithelial cells from the porcine intestine while one strain was classed as weakly-adherent . All lactobacilli showed inhibitory activity against indicator bacteria in the presence of glucose . Lactate and acetate were the principal final products of glucose fermentation in all strains . Only three strains produced H2O2 in detectable amounts.

Lett Appl Microbiol, 1997 Dec, 25(6), 419 - 25
Electrotransformation of Lactobacillus plantarum using linearized plasmid DNA; Thompson JK et al.; Evidence is presented that linearized plasmid DNA is capable of electrotransforming Lactobacillus plantarum at a frequency 500-fold lower than with the covalently closed circular molecule . When the linearized plasmid was religated prior to transformation the transformation efficiency was < 10-fold higher, suggesting that open circular plasmid was only slightly more efficient in the transformation of Lact . plantarum than linear DNA . This observation has implications for direct cloning into this species since the high background transformation frequency produced by the linear DNA could potentially obscure the recovery of clones . Nevertheless, using positive selection for enhanced chloramphenicol resistance, cloned fragments of Lact . helveticus DNA were obtained using the shuttle vector pGKV110.

Lett Appl Microbiol, 1997 Dec, 25(6), 401 - 4
Characterization of a bacteriophage for Carnobacterium divergens NCFB 2763 by host specificity and electron microscopy; Manchester LN; Carnobacterium divergens NCFB 2763 was used to isolate bacteriophage cd1 from minced beef using an enrichment isolation technique . Host specificity testing showed that it exhibited lytic activity only against a limited number of C . divergens strains . No activity was observed against any of the C . gallinarum, C . mobile, C . piscicola, Enterococcus durans, Lactobacillus plantarum and Lact . brevis strains tested . Anaerobic incubation had no effect on the host specificity pattern . Bacteriophage cd1 belongs to Bradley group B and on average the head was 94 nm, the tail 103 x 23 nm and the base plate 48 x 32 nm.

Biochemistry, 1997 Dec 16, 36(50), 15909 - 17
A novel dCMP methylase by engineering thymidylate synthase; Agarwalla S et al.; X-ray crystal structures of binary complexes of dUMP or dCMP with the Lactobacillus caseiTS mutant N229D, a dCMP methylase, revealed that there is a steric clash between the 4-NH2 of dCMP and His 199, a residue which normally H-bonds to the 4-O of dUMP but is not essential for activity . As a result, the cytosine moiety of dCMP is displaced from the active site and the catalytic thiol is moved from the C6 of the substrate about 0.5 A further than in the wild-type TS-dUMP complex . We reasoned that combining the N229D mutation with mutations at residue 199 which did not impinge on the 4-NH2 of dCMP should correct the displacements and further favor methylation of dCMP . We therefore prepared several TS N229D mutants and characterized their steady state kinetic parameters . TS H199A/N229D showed a 10(11) change in specificity for methylation of dCMP versus dUMP . The structures of TS H199A/N229D in complex with dCMP and dUMP confirmed that the position and orientation of bound dCMP closely approaches that of dUMP in wild-type TS, whereas dUMP was displaced from the optimal catalytic binding site.

J Perinat Med, 1997, 25(5), 406 - 17
Prevention of prematurity . A review of our activities during the last 25 years; Saling E; For 25 years we have been engaged in programs for prevention of prematurity . In the initial stages we tried to use lists which might indicate increased risk of prematurity to select groups with higher disposition in this direction, and to initiate more intensive care with these patients . The earlier results have been positive, but such programs required such high expenditure (of time, energy, and cost) that they could not permanently be maintained . Another supporting contribution for prematurity prevention was the introduction of vaginal disinfectant measures in cases of PROM . Historically, one of the most urgent tasks of obstetrics has been and is the reduction in the unwanted birth rate of very small prematures infants . Long-lasting impairments of these infants still occur too frequently . Ascending genital infections, particularly before 32 gestational weeks, are the most important cause of prematurity . This has been confirmed by the excellent results achieved after creating a complete barrier by an operative total cervical occlusion in cases with recurrent late abortions . It is difficult to realize programs for prematurity prevention based on socio-economic factors, because of the expense with the necessary increase in time and staff . Our new "Prematurity-Prevention-Program" is based mainly on the hypothesis that the ascension of genital infection directly affects prematurity . We found that in women with prematurity symptoms, signs of impairment of the immune system could be found, thus reinforcing the assumption that ascending infections are probably enhanced by such impairments . The best chance of preventing early prematurity is to employ a prophylactic screening program, preferably including self pH-measurement of all pregnant patients and paying additional attention to all other risk factors . The preliminary results of our "Prematurity-Prevention-Program" were encouraging . The rate of very small prematures with birth weight of less than 1.500 g in all participating pregnant patients is now clearly lower at 1.4% than in immediately previous pregnancies when the rate was 7.8% . The rate of extremely small infants of less than 1.000 g amounts now to 1.0%, compared to 4.0% previously . From another retrospective evaluation, we found that the earlier in the pregnancy the prematures are born, the more often their mothers have had pathologically elevated vaginal pH-levels upon admission . In premature births at less than 32 weeks of gestation, all fifteen of the mothers had increased pH-levels . For premature births of later gestation, the frequency was only 61% . Further, we noted that in 67% of all the nearly 700 pregnant patients evaluated, consistently normal pH-levels were present, while in 33% they were increased . In cases with increased vaginal pH-levels, lactobacillus acidophilus treatment was successful in more than 80% of the 75 patients after therapy of 5 +/- 3 days . By our program, we feel that a decisive step has been taken in achieving practical and efficient means of preventing premature births.

Biochemistry, 1997 Dec 23, 36(51), 16147 - 54
The GTP effector site of ornithine decarboxylase from Lactobacillus 30a: kinetic and structural characterization; Oliveira MA et al.; A nucleotide effector site of the biodegradative form of ornithine decarboxylase from Lactobacillus 30a (OrnDC L30a) has been identified . OrnDC L30a activity at pH 8.0, where the enzyme is normally inactive, is stimulated by GTP and dGTP and to a lesser extent by GDP but not by ATP, CTP, or UTP . The pH profile indicates that activation by GTP is reflected by an increase in kcat/KM,orn (above pH 6.8), while Vmax remains constant over the pH range 4.0-9 . 0 . Scatchard plot analysis shows that GTP binds to OrnDC L30a at both pH 5.8 (KD = 0.11 microM) and pH 8.0 (KD = 1.6 microM), but unexpectedly, half-site binding is observed at the higher pH . The OrnDC L30a dodecamer dissociates into dimers at high pH in the presence or absence of GTP . The GTP binding site was located in difference electron density maps using low-resolution X-ray data . This represents a new type of GTP binding site . A model explaining the activation of OrnDC L30a by GTP is presented.

Caries Res, 1998, 32(1), 51 - 8
Ecological study of Streptococcus mutans, Streptococcus sobrinus and Lactobacillus spp . at sub-sites from approximal dental plaque from children; Babaahmady KG et al.; Previous immunofluorescence (IF) studies have indicated that Streptococcus mutans may preferentially colonise specific sub-sites within approximal plaque . The present study aimed to extend these observations to other mutans streptococci and lactobacilli in such gingival margin plaque . Two hundred and seventy approximal plaque samples were taken from 90 teeth (3 from each tooth) in 64 children; three gingival margin sub-sites in relation to the contact area: away from (A), to the side of(S) and below (B) the contact area . Samples were processed by indirect IF using high-titred polyclonal anti-S . mutans 'c', anti-S . sobrinus 'd', anti-L . casei and anti-L . acidophilus antisera . An overall positive association was found between S . mutans 'c' and S . sobrinus 'd' (p < 0.001) . Significant differences (p < 0.1) were found between the proportional counts at each sub-site for S . mutans 'c': A = 39%, S = 51% and B = 70%, and for S . sobrinus 'd' 21, 33 and 49% . Mutans streptococci (MS) appeared to preferentially colonise the sub-site below the contact area (B = 81%), compared with sub-sites A and S (48 and 62%, respectively) . S . mutans 'c' and S . sobrinus 'd' were detected together at subsites A = 12%, S = 22%, and B = 38%, with proportional counts at B sites being higher than those at A (B > A, p < 0.01, and B > S, p < 0.05) . Lactobacillus spp . were isolated rarely, and were usually found together with MS . There was a positive relationship between the presence of lactobacilli or MS and caries (white spot lesions only), although these species could frequently be isolated from noncarious sites . The presence of both S . mutans 'c' and S . sobrinus 'd' were strongly correlated with early caries lesions . In addition, this study confirmed the variation in the microflora at different sub-sites within approximal dental plaque.

Caries Res, 1998, 32(1), 5 - 9
Salivary findings, daily medication and root caries in the old elderly; Narhi TO et al.; Root caries is one of the main dental problems among the dentate old elderly . The aim of our study was to evaluate the occurrence of root caries in 196 dentate elderly (mean age 79.3) in relation to their salivary flow rate, buffering capacity and salivary microbial counts . These subjects participated in the oral health component of the Helsinki Aging Study in 1990-1991 . Clinical oral examinations included assessment of the state of root surfaces and salivary flow rates, both paraffin-wax-stimulated and unstimulated . Salivary buffering capacity and the growth of salivary mutans streptococci, lactobacilli and yeasts were determined by means of commercially available kits . Root caries occurred in 52% of men and in 35% of women (p < 0.05) . Number of decayed (DRS) and decayed or filled (DFRS) root surfaces correlated (r = 0.16 to 0.26) with salivary microbial counts . No correlation appeared between DRS and subjects' salivary flow rates . Basic estimates on the association between DRS and salivary findings showed that microbial counts only produced significant odds ratios, from 2.0 to 3.5 . However, in a log-linear model high salivary mutans streptococci and yeast counts together with male gender were associated with greater occurrence of root caries.

J Dent Res, 1998 Jan, 77(1), 73 - 80
Longitudinal analysis of the association of human salivary antimicrobial agents with caries increment and cariogenic micro-organisms: a two-year cohort study; Kirstila V et al.; Previous studies of the possible associations of salivary antimicrobial agents with dental caries have given controversial results, obviously mainly because almost all studies have been cross-sectional . Our aim was to find out, in a two-year longitudinal follow-up study, the associations among selected salivary non-immune and immune antimicrobial variables, cariogenic bacteria, and caries increment . The study population was comprised of 63 subjects, all of whom had their 13th birthday during the first study year . In addition to a comprehensive dental examination at baseline and after 2 yrs, paraffin-stimulated whole saliva samples were collected in a standardized way at six-month intervals . Saliva samples were analyzed for flow rate, buffer effect, lysozyme, lactoferrin, total peroxidase activity, hypothiocyanite, thiocyanate, agglutination rate, and total and specific anti-S . mutans IgA and IgG, as well as for numbers of total and mutans streptococci, lactobacilli, and total anaerobic bacteria . Cluster analysis and Spearman-Rank correlation coefficients were used to explore possible associations between and among the studied variables . During the two-year period, a statistically significant increase was observed in flow rate, thiocyanate, agglutination rate, anti-S . mutans IgA antibodies, lactobacilli, and total anaerobes, whereas lysozyme, lactoferrin, and total and anti-S . mutans IgG antibodies declined significantly . Based on various analyses, it can be concluded that, at baseline, total IgG and hypothiocyanite had an inverse relationship with subsequent two-year caries increment, anti-S . mutans IgG antibodies increased with caries development, and mutans streptococci and lactobacilli correlated positively with both baseline caries and caries increment . Total anaerobic microflora was consistently more abundant among caries-free individuals . In spite of the above associations, we conclude that none of the single antimicrobial agents as such has sufficiently strong power to have diagnostic significance in vivo with respect to future caries.

J Dent Res, 1998 Jan, 77(1), 60 - 7
Effects of various resin composite (co)monomers and extracts on two caries-associated micro-organisms in vitro; Hansel C et al.; Previous studies have shown that extracts of various filling materials, e.g., resin composites, may influence the growth of cariogenic micro-organisms . The purpose of this study was to examine the effects of important resin composite (co)monomers (Bis-GMA, UDMA, TEGDMA, EGDMA) and extracts of two commercial dental composites with similar composition (composite A, Arabesk; composite S, Superlux) on the growth of the two cariogenic bacterial pathogens Streptococcus sobrinus and Lactobacillus acidophilus . It was found that neither the monomers Bis-GMA and UDMA, nor the comonomer EGDMA, nor the extract of composite A influenced the growth of S . sobrinus in the log phase . The comonomer TEGDMA and the extract of composite S were found to stimulate growth in the log phase, but this stimulation was not statistically significant . However, EGDMA, TEGDMA, and the extract of composite S did stimulate the total growth of S . sobrinus . In the assays with L . acidophilus, Bis-GMA, UDMA, and the extract of composite A inhibited the growth in the log phase, whereas TEGDMA stimulated it . Furthermore, EGDMA, TEGDMA, and the extract of composite S stimulated the biomass production of L . acidophilus . We conclude from our results that a release of EGDMA and TEGDMA from resin composites should be avoided due to their growth-stimulating effects on the caries-associated micro-organisms S . sobrinus and L . acidophilus.

Can J Microbiol, 1997 Nov, 43(11), 1063 - 8
Isolation and characterization of promoters from the Lactobacillus casei temperate bacteriophage A2; Garcia P et al.; Random Sau3A1 DNA fragments from the temperate Lactobacillus bacteriophage A2 were cloned into the promoter-probe plasmid pGKV210 . Seven DNA fragments with promoter activity were selected, after transformation of Escherichia coli and Lactococcus lactis, subsp, lactis, through the chloramphenicol resistance they conferred to the corresponding clones . The seven promoters were functional in Lactobacillus casei . Their strength was analysed by measuring the levels of chloramphenicol resistance and chloramphenicol acetyltransferase activity induced in each host . The nucleotide sequences of these fragments were determined and primer extension analysis was used to locate the initiation site of transcription from each promoter in E coli . The promoters contained -10 and -35 regions similar to the consensus sequences of E . coli and Lactobacillus promoters.

J Dairy Sci, 1997 Dec, 80(12), 3107 - 13
Incorporation of cholesterol into the cellular membrane of Lactobacillus acidophilus ATCC 43121; Noh DO et al.; Cholesterol that was assimilated by Lactobacillus acidophilus ATCC 43121 was not metabolically degraded; most of it was recovered with the cells . Cells that were grown in the presence of cholesterol micelles and bile salts were more resistant to lysis by sonication than were those grown in their absence, suggesting a possible alteration of the cell wall or membrane . Cholesterol assimilation occurred during growth at pH 6.0 as well as during growth without pH control . Part of the cholesterol that was assimilated by cells was recovered in the membrane fractions of cells grown under both conditions . There was no difference in the amount taken up from cholesterol micelles that were prepared using dioleoyl L-alpha-phosphatidylcholine or distearoyl L-alpha-phosphatidylcholine . Thus, the type of fatty acid (unsaturated or saturated) in the phospholipid did not influence the assimilation . As the amount of Tween 80 in the growth media increased beyond 0.05%, cholesterol uptake decreased, and the amount of growth remained the same . The higher concentrations of Tween 80 may have adversely affected the permeability of the cells.

J Dairy Sci, 1997 Dec, 80(12), 3099 - 106
Isolation and characterization of a tributyrin esterase from Lactobacillus plantarum 2739; Gobbetti M et al.; An intracellular tributyrin esterase from Lactobacillus plantarum 2739 was purified to homogeneity by chromatography on DEAE cellulose, Sephacryl 200, carboxymethylcellulose, and Mono Q . The enzyme E2 was separated on DEAE cellulose from a second esterase, E1, and a minor esterase . Additional minor esterases were separated from E2 during chromatography on Sephacryl . E2 was a monomer with a relative molecular mass of approximately 85 kDa . The enzyme was most active at pH 7 and 35 degrees C and retained about 30% of maximal activity at pH 5 and about 18% at 12 degrees C . E2 was strongly inhibited by 1 mM phenylmethylsulfonyl fluoride, Hg2+, or Ag+ and was moderately stimulated by Ca2+ and Mg2+ . E2 was active on beta-naphthyl esters of fatty acids from C2 to C10 with a preference for beta-naphthyl butyrate . Tributyrin and, to a lesser extent, tricaprylin and milk fat were also hydrolyzed . Partially purified E1 was more active on tributyrin than was E2 . The sequence of the first 15 N-terminal amino acids of purified E2 was Ser-Asn-Glu-His-Thr-Gln-Glu-Val-Leu-Asn-Gln-Thr-Val-Ala-Asp . The enzyme showed a decimal reduction value at 70 degrees C of 2.5 min . The Michaelis constant of E2 on beta-naphthyl butyrate was 0.36 mM.

Appl Environ Microbiol, 1998 Jan, 64(1), 27 - 33
Anaerobic killing of oral streptococci by reduced, transition metal cations; Dunning JC et al.; Reduced, transition metal cations commonly enhance oxidative damage to cells caused by hydroperoxides formed as a result of oxygen metabolism or added externally . As expected, the cations Fe2+ and Cu+ enhanced killing of Streptococcus mutans GS-5 by hydroperoxides . However, unexpectedly, they also induced lethal damage under fully anaerobic conditions in a glove box with no exposure to O2 or hydroperoxides from initial treatment with the cations . Sensitivities to anaerobic killing by Fe2+ varied among the organisms tested . The oral streptococci Streptococcus gordonii ATCC 10558, Streptococcus rattus FA-1, and Streptococcus sanguis NCTC 10904 were approximately as sensitive as S . mutans GS-5 . Enterococcus hirae ATCC 9790, Actinomyces viscosus OMZ105E, and Actinomyces naeslundii WVU45 had intermediate sensitivity, while Lactobacillus casei ATCC 4646 and Escherichia coli B were insensitive . Killing of S . mutans GS-5 in response to millimolar levels of added Fe2+ occurred over a wide range of temperatures and pH . The organism was able to take up ferrous iron, but ferric reductase activity could not be detected . Chelators, uric acid, and thiocyanate were not effective inhibitors of the lethal damage . Sulfhydryl compounds, ferricyanide, and ferrocyanide were protective if added prior to Fe2+ exposure . Fe2+, but not Fe3+, acted to reduce the acid tolerance of glycolysis by intact cells of S . mutans . The reduction in acid tolerance appeared to be related directly to Fe2+ inhibition of F-ATPase, which could be assayed with permeabilized cells, isolated membranes, or F1 enzyme separated from membranes . Cu+ and Cu2+ also inhibited F-ATPase and sensitized glycolysis by intact cells to acid . All of these damaging actions occurred anaerobically and thus did not appear to involve reactive oxygen species.

Gene, 1997 Dec 19, 204(1-2), 219 - 25
Purification and DNA-binding properties of the integrase protein Int encoded by Lactobacillus plantarum phage; Yasukawa H et al.; The Lactobacillus plantarum temperate phage phi g1e (42,259 bp) encodes an integrase gene int linked to a phage attachment site attP (Kakikawa et al., 1997) . To investigate phi g1e recombination, the integrase protein Int was overproduced in Escherichia coli under the T7 promoter, and purified . The Int protein had an apparent molecular mass of 42.0 kDa, corresponding well with that (45.5 kDa) predicted from the DNA sequence . Amino-acid sequencing revealed that the N-terminal 20 amino-acids of the purified Int protein completely coincided with those deduced from the DNA sequence, although deficient in the first methionine . Gel mobility-shift assays demonstrated that Int bound specifically to the attP region . In addition, footprinting analysis showed that Int protected about 35 bases, containing the 24-bp core domain at attP, from DNase I attack . These results are indicative of site-specific interaction of Int with the attP site, the reaction prerequisite for integration and excision of the phi g1e genome into and/or out of the host chromosome.

Prog Nucleic Acid Res Mol Biol, 1998, 59, 205 - 55
Life on the salvage path: the deoxynucleoside kinase of Lactobacillus acidophilus R-26; Ives DH et al.; In Lactobacillus acidophilus R-26, the synthesis of DNA precursor deoxynucleotides occurs exclusively by salvage of deoxynucleosides, beginning with phosphorylation by four deoxynucleoside kinases . Subunits bearing three of these activities are uniquely organized into two heterodimers, deoxyadenosine/deoxycytidine kinase (dAK/dCK) and deoxyadenosine/deoxyguanosine kinase (dAK/dGK), which, along with a distinct deoxythymidine kinase (TK), catalyze the parallel first committed steps of dNTP biosynthesis . Whereas TK is common to most prokaryotes (and eukaryotes), the other three activities that are the emphasis of this review are quite unusual in bacteria . Each activity is regulated in cis by its homologous end-product (dNTP) which is understood to act as a multisubstrate inhibitor capable of binding to both nucleoside and phosphate subsites . Conversely, the inactive dAK subunit is progressively activated by 1) association with a dGK or dCK subunit and 2) the conformationally driven heterotropic affect of dGuo or dCyd bound to the opposing subunit . Limited proteolysis has proven to be a powerful probe of conformational states . Further indication of conformational or structural differences between dAK and dGK (or dCK) is that the former follows an ordered kinetic path, while dGK or dCK exhibits rapid-equilibrium random kinetics . The multi-substrate behavior of end-product binding provides a convenient new diagnostic tool for distinguishing kinetic mechanisms . Tandem dak-dgk genes have been cloned from Lactobacillus DNA and expressed in Escherichia coli as dAK/dGK, utilizing the associated promoter . Sequence alignments reveal 65% identity in their DNA and 61% in their derived amino acid sequences . Encoded N-terminal sequences are identical for the first 18 residues, and both subunits share conserved sequences in common with adenylate kinase and viral TK . A more unusual conserved element, which appears to play a role in the activation of dAK, resembles the G2 loop of p21 ras . Remarkably, no homologous gene(s) for the dAK/dCK pair could be found . Comparisons of amino acid sequences, isoelectric pHs and subunit masses strongly indicated that native dCK and dGK are identical in sequence, except at their extreme N-termini (M-IVL for dCK and -TVIVL for dGK), suggesting that processing of a common precursor occurs in Lactobacillus . Accordingly, deletion of codons 2 and 3 from dgk resulted in the expression of dAK/dCK in the E . coli host; its kinetic properties are indistinguishable from those of native dAK/dCK . Subcloning the dgk or engineered dck gene resulted in expression of active dGK or dCK homodimers, each with a virtually unchanged Km toward its primary deoxynucleoside . However, in common with human dCK, dCK (or dGK) homodimer exhibits secondary activities with much larger Kms towards dAdo and dGuo (or dCyd) . dCTP (or dGTP) is the best inhibitor of all three activities of the respective homodimer . Fully active heterodimers can be reconstituted simply by mixing a homodimer with independently expressed (inactive) dAK.

Pediatr Infect Dis J, 1997 Dec, 16(12), 1103 - 7
Bacteriotherapy with Lactobacillus reuteri in rotavirus gastroenteritis; Shornikova AV et al.; BACKGROUND: Certain lactic acid bacteria may accelerate recovery from acute diarrhea . Lactobacillus reuteri is a commonly occurring Lactobacillus species with therapeutic potential in diarrhea . DESIGN: Prospective, randomized, placebo-controlled trial in two hospitals . METHODS: Children between 6 and 36 months of age admitted for rotavirus-associated diarrhea were randomized into three groups to receive either 10(10) or 10(7) colony-forming units (cfu) of L . reuteri or a matching placebo once a day for up to 5 days . RESULTS: The main effect of L . reuteri was on the duration of watery diarrhea . The mean (+/-SD) duration of watery diarrhea after initiation of treatment was 2.5 (1.5) days in the placebo group (n = 25) vs . 1.9 (0.9) days in the small dosage (n = 20) and 1.5 (1.1) days in the large dosage (n = 21) L . reuteri recipients (P = 0.01) . By the second day of treatment watery diarrhea persisted in 80% of the placebo, 70% of the small dosage and 48% of the large dosage L . reuteri recipients (P = 0.04, large dosage vs . placebo) . Stool cultures for lactobacilli confirmed that administration of L . reuteri resulted in good colonization of the GI tract . The mean (+/-SD) of total Lactobacillus count 2 days after treatment initiation was 2.8 (1.6) log 10 cfu/g in the placebo group, 4.5 (2.0) log 10 cfu/g in the small dosage L . reuteri group and 6.1 (1.2) log 10 cfu/g in the large dosage L . reuteri group (P = 0.0004) . CONCLUSIONS: L . reuteri effectively colonized the gastrointestinal tract after administration and significantly shortened the duration of watery diarrhea associated with rotavirus . There was a correlation between the dosage of L . reuteri and the clinical effect.

Microbiology, 1997 Dec, 143 ( Pt 12), 3899 - 905
Lactobacilli carry cryptic genes encoding peptidase-related proteins: characterization of a prolidase gene (pepQ) and a related cryptic gene (orfZ) from Lactobacillus delbrueckii subsp . bulgaricus; Rantanen T et al.; Two genes, pepQ and orfZ, encoding a prolidase and a prolidase-like protein, respectively, were cloned and characterized from Lactobacillus delbrueckii subsp . bulgaricus . The identity of the pepQ and orfZ genes with the Lactobacillus delbrueckii subsp . lactis prolidase gene (pepQ) was shown to be 98% and 60%, respectively . Both pepQ and orfZ were preceded by a putative promoter region . Northern analysis of pepQ mRNA revealed a 1.1 kb transcript indicating that pepQ forms a monocistronic transcriptional unit . Under the growth conditions used, no evidence was obtained that orfZ was expressed, either by mRNA size determination in Northern analysis or by primer extension analysis . With reverse transcription-PCR, however, the presence of monocistronic orfZ transcripts was established . The orfZ gene could also be overexpressed in E . coli using the vector pKK223-3 . The size of the protein synthesized, 41 kDa, confirmed the molecular mass of OrfZ calculated according to DNA sequence analysis . In contrast to PepQ, which showed a substrate specificity characteristic of prolidase enzymes, no enzymic activity for the orfZ-encoded protein was found with the peptide substrates tested . These results indicate that orfZ is a cryptic gene, which is expressed at a very low level under the growth conditions used . It is noteworthy that homologues of the Lb . delbrueckii subsp . bulgaricus orfZ and pepQ genes appeared to be present in both Lb . delbrueckii subsp . lactis and Lactobacillus helveticus.

Radiats Biol Radioecol, 1997 Sep-Oct, 37(5), 743 - 9
{Biological preparation based on Lactobacillus acidophilus, a new agent in the early treatment of combined radiation-thermal injuries}; Budagov RS et al.; Male mice F1 (CBA x C57BL6) were used for experiments . Animals were exposed to 7 Gy gamma-radiation and additionally inflicted to full-thickness thermal burn 10% body surface . As it has been revealed, single subcutaneous injection of the created biopreparation based on inactivated lactobacillus microbic biomass increased mice survival with combined injury from 23% to 73% . Therapeutic efficacy of this remedy did not correlate with postradiation damages of the hemopoietic system . Injection of killed L . acidophilus mixture strikingly averted development of the intestine autoinfection . Possible mechanisms of the benefit therapeutic action of the new preparation are discussed.

Chem Biol Interact, 1997 Oct 24, 106(3), 201 - 12
Inhibition of thymidylate synthase and cell growth by the phenanthroindolizidine alkaloids pergularinine and tylophorinidine; Rao KN et al.; Biological activity of the phenanthroindolizidine alkaloids pergularinine (PGL) and tylophorinidine (TPD) isolated from the Indian medicinal herb Pergularia pallida has been evaluated and assessed for the first time employing thymidylate synthase (TS) (5,10-CH2H4 PteGlu: dUMP-C-methyltransferase, EC 2.1.1.45), a key target enzyme in cancer chemotherapy . TS used in the present investigations was purified from Lactobacillus leichmannii . Toxicity studies showed that PGL and TPD were potently toxic and inhibited growth of L.leichmannii cells . Both PGL and TPD significantly inhibited TS activity (IC50 = 40 and 45 microM, respectively) . PGL concentrations > 80 microM and TPD concentrations > 90 microM resulted in a complete loss of the TS activity, thus suggesting that both these phenanthroindolizidine alkaloids are promising potential antitumor agents . Our results show that the alkaloid-binding to TS is irreversibly tight through a probable covalent linkage . Inhibition kinetics reveal that the enzyme has Ki values of 10 x 10(-6) and 9 x 10(-6) M for PGL and TPD, respectively and that the inhibition in both the cases is a simple linear 'noncompetitive' type.

Lakartidningen, 1997 Oct 1, 94(40), 3493 - 5
{Animal husbandry and food handling today . Current food preservation has changed the intestinal flora}; Ahrne S et al.; In the modern world, as refrigerated storage has replaced lactic acid fermentation methods of food preservation, we no longer ingest large quantities of live lactobacilli with our food, but relatively large numbers of potentially pathogenic Gram-negative bacteria instead . In the brave new world, antibiotics are used as growth-promoting additives in animal feed in every country but Sweden . The antibiotics used in Europe at low dosages, and exempt from prescription requirements, include macrolides, streptogramins and nitro-imidazoles . There is reason to believe that avoparcin, recently banned in Europe as an antibiotic animal feed additive, has contributed to the occurrence of vancomycin-resistant enterococci in humans . Animal foodstuffs production in Europe and the USA is so intensive that it provides very favourable conditions for the spread of bacteria . Pig, cattle and poultry breeding in Europe are beset by formidable difficulties in the form of Salmonella infections, which constitute not only a hygiene but also a clinical problem . Sweden, the bravest of brave new worlds, faces an increase in the influx of domestic animals and foodstuffs from other countries, and in general less restrictive regulations concerning food production and animal husbandry, but reduced powers of control . Thus, we may expect problems both with pathogens (traditional ones such as Salmonella, and potential ones such as food-spoilage Gram-negative bacteria), and with antibiotic-resistant bacteria in our food-stuffs, to become greater.

Klin Med (Mosk), 1997, 75(7), 47 - 9
{Clinical manifestations and treatment of intestinal dysbacteriosis in patients with Flexner's dysentery}; Shakhmardanov MZ et al.; Flexner's dysentery is often accompanied with intestinal dysbacteriosis . Disbiotic changes in the intestine contribute to specific shigella endotoxins entering blood flow thus prolonging clinical symptoms of the underlying disease . Administration of bacterial biological preparations (bifidumbacterin forte, lactobacterin) relieves specific endotoxemia, reduces the duration of the disease and has an immunomodulating action.

Aust Dent J, 1997 Oct, 42(5), 343 - 6
Growth inhibition of oral bacteria related to denture stomatitis by anti-candidal chalcones; Sato M et al.; In the antimicrobial therapy of denture stomatitis, it is desirable to inhibit the growth of not only the primary causative organism, Candida albicans, but also other oral bacteria closely associated with the condition . Three synthetic anti-candidal chalcones were characterized and compared for their additional activity in inhibiting these causative bacteria . Among the tested chalcones, 2,4,2'-trihydroxy-5'-methylchalcone showed the highest activity for different Gram-positive bacteria . It inhibited the growth of streptococci, staphylococci and lactobacilli at 25.0-50.0 micrograms/mL which was lower than or comparable to its minimum inhibitory concentration for candida . It functioned with a bactericidal action and leaked 260 nm-absorbing substances from the streptococcal cells . The antimicrobial activity of 2,4,2'-trihydroxy-5'-methylchalcone against both primary and secondary causative agents suggests it could be useful as a potent therapeutic agent in denture stomatitis.

J Dairy Sci, 1997 Nov, 80(11), 2701 - 5
A modified form of a vitamin B12 compound extracted from whey fermented by Lactobacillus helveticus; Sato K et al.; The content of vitamin B12 in whey was reduced considerably during lactic acid fermentation, which was analogous to the lactic acid fermentation of milk . This apparent B12 decrease in whey was caused by B12 compounds that were unextractable by conventional extraction with potassium cyanide but that could be extracted by sonication and treatment by proteases such as pepsin and papain . Forms of the extracted B12 compounds were examined by bioautographies with Escherichia coli 215, coupled with cellulose acetate membrane electrophoresis or HPLC, and were identified as adenosylcobalamin, cyanocobalamin, and hydoroxocobalamin . A considerable amount of unidentified B12 was also detected, and this unidentified B12 compound seems to be the principal B12 compound that was unextractable from the cells.

Biosci Biotechnol Biochem, 1997 Nov, 61(11), 1947 - 8
Photocatalysis-dependent inactivation of Lactobacillus phage PL-1 by a ceramics preparation; Kakita Y et al.; A ceramics preparation (Cleansand-205), which was coated with a mixture of the oxides of Si, Al, Ti, and Ag, was found to inactivate Lactobacillus phage PL-1 suspended in a buffer solution . The inactivation of phage was dependent on the amounts of Cleansand-205 added, and the reaction obeyed almost first-order reaction kinetics . The phage inactivation was considerably accelerated by the presence of light.

Arch Oral Biol, 1997 Sep, 42(9), 595 - 9
Investigation of calcium-binding sites on the surfaces of selected gram-positive oral organisms; Rose RK et al.; Dental plaque is rich in anionic groups with a high calcium-binding capacity which may affect mineral dynamics at the tooth surface . The two major calcium-binding sites on Gram-positive cell surfaces are carboxylate groups (in proteins and peptidoglycan cross-links) and phosphate groups (in lipoteichoic and teichoic acid) . Equilibrium dialysis was used to measure calcium-binding capacities of whole cells and purified cell-wall material (CWM) from Streptococcus mutans R9, Strep . oralis EF186, Strep . gordonii NCTC 7865, Strep . downei NCTC 11391, Actinomyces naeslundii WVU627 and Lactobacillus casei AC413 . This material was stripped of phosphate (PS-CWM) and treated to mask carboxylate groups (CM-CWM) . Whole-cell calcium-binding capacities ranged from 240 (Strep . downei) to 50 (L . casei) mu mol/g (dry wt) . Differences in CWM, PS-CWM and CM-CWM calcium-binding capacities demonstrated the greater importance of phosphate in comparison with carboxylate groups in cell calcium binding . These data indicate that, in streptococci, calcium binding is predominantly phosphate group-based, especially in the teichoic acid-containing Strep . oralis . In the other species tested, calcium binding is predominantly carboxylate group-based.

Clin Infect Dis, 1997 Nov, 25(5), 1048 - 55
Lactobacillus bacteremia and endocarditis: review of 45 cases; Husni RN et al.; Lactobacilli are part of normal gastrointestinal and genitourinary flora but are an uncommon cause of bacteremia . We reviewed the cases of 45 patients with clinically significant lactobacillus bacteremia occurring over 15 years . Underlying conditions were common, including cancer (40%), recent surgery (38%), and diabetes mellitus (27%) . Twenty-two patients were in the intensive care unit at the time of onset of lactobacillus bacteremia . Eleven of the 45 patients were receiving immunosuppressive therapy, 11 were receiving total parenteral nutrition, and 23 had received antibiotics without activity against Lactobacillus prior to the occurrence of bacteremia . Bacteremia was polymicrobial in 27 patients and developed during hospitalization in 39 . Thirty-one patients died, but only one death was attributable to lactobacillus bacteremia . Lactobacilli are relatively avirulent pathogens that produce bacteremia in patients with serious underlying illnesses, many of whom have received prior antibiotic therapy that may select out for the organism . While rarely fatal in itself, lactobacillus bacteremia identifies patients with serious and rapidly fatal illness.

J Bacteriol, 1997 Dec, 179(24), 7812 - 5
Synthesis of nitric oxide from the two equivalent guanidino nitrogens of L-arginine by Lactobacillus fermentum; Morita H et al.; Ten strains of Lactobacillus fermentum that differed in origin converted metmyoglobin to nitrosylmyoglobin {a pentacoordinate nitric oxide (NO) complex of Fe(II) myoglobin} in MRS broth at pH 4.3 . Of the 10 strains, L . fermentum IFO 3956 possessed the strongest capacity to convert metmyoglobin to nitrosylmyoglobin . This strain synthesizes NO enzymatically from the two equivalent guanidino nitrogens of L-arginine . To our knowledge, this demonstrates for the first time the production of NO synthesized from the guanidino nitrogens of L-arginine by lactic acid bacteria . IFO 3956 may possess a bacterial NO synthase.

J Biochem (Tokyo), 1997 Oct, 122(4), 802 - 9
Involvement of Glu-264 and Arg-235 in the essential interaction between the catalytic imidazole and substrate for the D-lactate dehydrogenase catalysis; Taguchi H et al.; For Lactobacillus pentosus D-lactate dehydrogenase, the binding of 2-ketoacids is markedly stabilized through interactions between the protonated imidazole of His-296, an acid/base catalyst of the enzyme, and the carbonyl oxygen of 2-ketoacids . The replacement of Arg-235 with Gln destabilized the inhibitory binding of oxamate much more than that of formate, acetate, or propionate, and the Arg to Lys substitution specifically diminished only oxamate binding . On the other hand, replacement of a conserved Glu, Glu-264, with Gln severely impaired the enzyme activity and markedly reduced affinity to 2-keto acids . The pH dependence of the oxamate inhibition revealed that the substitutions of Arg-235 and Glu-264 induced a great loss of the imidazole-carbonyl interaction . However, replacement of Glu-264 with Asp, another acidic amino acid, affected the enzyme function less than the Glu to Gln substitution . In addition, both the Arg-235 and Glu-264 substitutions induced marked increases in the primary isotope effect on the catalysis, suggesting that these amino acids stimulate the hydrogen transfer step in the catalysis . We concluded, therefore, that the guanidino and carboxyl groups of Arg-235 and Glu-264, respectively, cooperatively promote the essential imidazole-substrate interaction, enhancing the substrate binding and catalysis.

FEMS Immunol Med Microbiol, 1997 Oct, 19(2), 111 - 4
Aggregation-promoting factor in human vaginal Lactobacillus strains; Kmet V et al.; A total of 60 Lactobacillus sp . strains were examined for expression of auto-aggregation and cell surface hydrophobicity . Isolates were obtained from the vagina of healthy women (n = 20) . The results obtained showed that the occurrence of cell surface hydrophobicity correlated with auto-aggregative activity in 12 homofermentative Lactobacillus sp . strains . The aggregation mechanism was mediated by the presence of an aggregation promoting factor (APF) in one Lactobacillus sp . strain, HV 142 . APF was confirmed by DNA hybridisation with a 1.3 kb PstI DNA fragment of recombinant plasmid pFDS containing the reading open frame of the APF gene derived from Lactobacillus plantarum 4B2 . Coaggregation activity was seen in three strains of auto-aggregative human vaginal lactobacilli and five strains of P-fimbriated uropathogenic Escherichia coli . Moreover, one of four Lactobacillus sp . strains (HV 389) aggregated with two of five E . coli tested . These results suggest that APF producing lactobacilli could represent a further mechanism in the interaction of commensal microflora with strains of uropathogenic E . coli.

Genitourin Med, 1997 Aug, 73(4), 291 - 6
The vagina has reducing environment sufficient for activation of Trichomonas vaginalis cysteine proteinases; Alderete JF et al.; BACKGROUND: Trichomonas vaginalis, a worldwide distributed sexually transmitted protozoan, is remarkable for synthesis of numerous, distinct cysteine proteinases, the significance of which is evidenced by the presence in vivo of soluble proteinases in secretions and antiproteinase antibody in serum of patients with trichomonosis . These proteinases purportedly play a role in host parasitism and immune evasion . OBJECTIVE: It is known that for cysteine proteinases to be functional, they must be activated by disulphide reducing reagents . Whether or not the host vaginal environment has the reducing environment essential for activation of the trichomonad cysteine proteinases is unknown . Our goal, therefore, was to determine whether or not vaginal secretions had sufficient reducing power to activate the trichomonad proteinases . METHODS: 48 vaginal washes (VWs) from patients were assayed for reducing equivalents and a score in dithiothreitol (DTT) reducing equivalents was assigned to each VW . Activation of trichomonad cysteine proteinases was then tested under the range of reducing equivalents detected from VWs . The possible protective effect of hydrogen peroxide, an oxidising agent produced by some Lactobacillus species, on proteinase activity was also determined . RESULTS: Nine of 48 VWs (18.7%) possessed < or = 10 microM DTT reducing equivalents, four VWs (8.3%) had from 20 microM DTT to 40 microM DTT reducing equivalents, and most (50%) were between 10 microM to 15 microM . Overall, the range in VWs was from approximately 10 microM to 40 microM reducing equivalents . Importantly, data suggest differential proteinase activation over this in vivo range of reducing level . Only two T vaginalis cysteine proteinase activities were stimulated at 2.5 microM DTT in contrast with all proteinase activities present at 40 microM DTT, albeit quantitatively diminished compared with the activity at 1 mM DTT, the concentration routinely used in vitro . Finally, hydrogen peroxide reversibly neutralised all trichomonad proteinases . CONCLUSIONS: These results show that the vagina of women has a reducing environment adequate for activation of trichomonad proteinases . The data underscore that the host environment plays a role in the host-parasite interrelation . Finally, hypotheses can now be formulated to help explain resistance and susceptibility to infection commonly reported among women and between men and women with trichomonosis.

Gene, 1997 Oct 1, 198(1-2), 149 - 57
Molecular characterization of the alpha-amylase genes of Lactobacillus plantarum A6 and Lactobacillus amylovorus reveals an unusual 3' end structure with direct tandem repeats and suggests a common evolutionary origin; Giraud E et al.; The alpha-amylase gene (amyA) of Lactobacillus plantarum A6 was isolated from the genome by polymerase chain reaction with degenerated oligonucleotides, synthesized according to the tryptic peptide amino acid sequences of the purified enzyme . Nucleic acid sequence analysis revealed one open reading frame of 2739 bp encoding a 913 amino acid protein . The amylase appears to be divided into two equal parts . The N-terminal part has the typical characteristics of the well-known alpha-amylase family (65% identity with the alpha-amylase of Bacillus subtilis and 97% identity with the partial sequence available for the alpha-amylase of Lactobacillus amylovorus) . The C-terminal part displays a fairly unusual structure . It consists of four direct tandem repeated sequences of 104 amino acids sharing 100% similarity . The complete nucleotide sequence of the alpha-amylase gene of L . amylovorus was also determined . An open reading frame of 2862 bp encoding a 954 amino acid protein was identified . Perfect homology between the two amyA genes was observed in the N-terminal region . The C-terminal part of L . amylovorus alpha-amylase also included tandem repeat units but striking differences were observed: (i) the addition of one repeat unit; (ii) a shorter, 91 amino acid repetition unit . These structural homologies suggest that both genes have a common ancestor and may have evolved independently by duplication with subsequent recombination and mutation.

Acta Odontol Scand, 1997 Oct, 55(5), 282 - 91
Dental caries and related factors in 88- and 92-year-olds . Cross-sectional and longitudinal comparisons; Lundgren M et al.; Our aim was to compare two groups of 88- and 92-year-olds (n = 92 and n = 40), respectively, with regard to teeth, caries, and salivary and microbial conditions . Oral variables were analyzed in relation to functional capacity and use of cardiovascular agents and psychoactive drugs . Untreated root caries, plaque score, and counts of lactobacilli increased between the ages of 88 and 92 years (P < 0.01) . Nine of the 24 longitudinally followed up subjects had lost 1-5 teeth over 4 years, and 17 subjects had developed new caries (DFS) . The mean caries increment over 4 years was 1.3 coronal and 3.6 root surfaces, and new DFS per 100 surfaces at risk was 4.3 coronal and 17.5 root surfaces . Plaque score and final pH of buffer capacity increased (P < 0.05 and 0.01, respectively), whereas saliva flow, independent of gender, was unchanged . Use of cardiovascular agents and psychoactive drugs was associated with a deteriorated dental status.

Appl Environ Microbiol, 1997 Nov, 63(11), 4581 - 4
Controlled gene expression systems for lactic acid bacteria: transferable nisin-inducible expression cassettes for Lactococcus, Leuconostoc, and Lactobacillus spp; Kleerebezem M et al.; A transferable dual-plasmid inducible gene expression system for use in lactic acid bacteria that is based on the autoregulatory properties of the antimicrobial peptide nisin produced by Lactococcus lactis was developed . Introduction of the two plasmids allowed nisin-inducible gene expression in Lactococcus lactis MG1363, Leuconostoc lactis NZ6091, and Lactobacillus helveticus CNRZ32 . Typically, the beta-glucuronidase activity (used as a reporter in this study) remained below the detection limits under noninducing conditions and could be raised to high levels, by addition of subinhibitory amounts of nisin to the growth medium, while exhibiting a linear dose-response relationship . These results demonstrate that the nisin-inducible system can be functionally implemented in lactic acid bacteria other than Lactococcus lactis.

Appl Environ Microbiol, 1997 Nov, 63(11), 4528 - 33
Imaging of Lactobacillus brevis single cells and microcolonies without a microscope by an ultrasensitive chemiluminescent enzyme immunoassay with a photon-counting television camera; Yasui T et al.; An ultrasensitive chemiluminescent enzyme immunoassay (CLEIA) was developed for the rapid detection and quantification of Lactobacillus brevis contaminants in beer and pitching yeast (Saccharomyces cerevisiae slurry collected for reinoculation) . L . brevis cells trapped on a 47-mm nucleopore membrane (0.4-micron pore size) were reacted with a peroxidase-labelled Lactobacillus group E antibody and then subjected to an enhanced CLEIA analysis with 4-iodophenol as the enhancer . The combination of a nucleopore membrane with low background characteristics that enables the antigen-antibody reaction to proceed through the pores of the membrane and a labelled antibody prepared by the maleimide hinge method with minimal nonspecific binding characteristics was essential to minimize background in the detection of single cells . An ultrahigh sensitive charge-coupled device (CCD) camera equipped with a fiber optics image intensifier permitted the imaging of single cells . A clear correlation existed between the number of luminescent spots observed and the plate count {y (CLEIA) = 0.990x (plate count) + 15.9, where n = 7, r = 0.993, and P < 0.001} . Microscopic observation confirmed that the luminescent spots were produced by single cells . This assay could be used to detect approximately 20 L . brevis cells in 633 ml of beer within 4 h . Our ultrasensitive CLEIA could also be used to detect microcolonies approximately 20 microns in diameter which had formed on a membrane after 15 to 18 h of incubation . This method, which we called the microcolony immunoluminescence (MIL) method, increased the signal-to-noise ratio dramatically . The MIL method could be used to detect a 10(0) level of L . brevis contamination in 633 ml of beer and a 1/10(8) level of L . brevis contamination in pitching yeast within 1 day (15 to 18 h to form microcolonies and 2 h for CLEIA).

Appl Environ Microbiol, 1997 Nov, 63(11), 4158 - 63
Effects of lactobacilli on yeast-catalyzed ethanol fermentations; Narendranath NV et al.; Normal-gravity (22 to 24 degrees Plato) wheat mashes were inoculated with five industrially important strains of lactobacilli at approximately 10(5), approximately 10(6), approximately 10(7), approximately 10(8), and approximately 10(9) CFU/ml in order to study the effects of the lactobacilli on yeast growth and ethanol productivity . Lactobacillus plantarum, Lactobacillus paracasei, Lactobacillus #3, Lactobacillus rhamnosus, and Lactobacillus fermentum were used . Controls with yeast cells but no bacterial inoculation and additional treatments with bacteria alone inoculated at approximately 10(7) CFU/ml of mash were included . Decreased ethanol yields were due to the diversion of carbohydrates for bacterial growth and the production of lactic acid . As higher numbers of the bacteria were produced (depending on the strain), 1 to 1.5% (wt/vol) lactic acid resulted in the case of homofermentative organisms . L . fermentum, a heterofermentative organism, produced only 0.5% (wt/vol) lactic acid . When L . plantarum, L . rhamnosus, and L . fermentum were inoculated at approximately 10(6) CFU/ml, an approximately 2% decrease in the final ethanol concentration was observed . Smaller initial numbers (only 10(5) CFU/ml) of L . paracasei or Lactobacillus #3 were sufficient to cause more than 2% decreases in the final ethanol concentrations measured compared to the control . Such effects after an inoculation of only 10(5) CFU/ml may have been due to the higher tolerance to ethanol of the latter two bacteria, to the more rapid adaptation (shorter lag phase) of these two industrial organisms to fermentation conditions, and/or to their more rapid growth and metabolism . When up to 10(9) CFU of bacteria/ml was present in mash, approximately 3.8 to 7.6% reductions in ethanol concentration occurred depending on the strain . Production of lactic acid and a suspected competition with yeast cells for essential growth factors in the fermenting medium were the major reasons for reductions in yeast growth and final ethanol yield when lactic acid bacteria were present.

J Dairy Sci, 1997 Oct, 80(10), 2318 - 24
Properties of porcine and yogurt lactobacilli in relation to lactose intolerance; Burton JP et al.; Lactobacilli that had been isolated from the stomach of piglets were tested for properties relevant to the production of fermented milk products for consumption by lactose-intolerant humans . The strains were characterized for beta-galactosidase activity, the ability to reduce the lactose concentration of milk, viability, and pH of the fermented milk over a 30-d period . Strains that had favorable attributes were studied further, and the optimal pH for beta-galactosidase activity, ability to grow in the presence of bile salts, and ability to deconjugate bile salts were determined . Commercial yogurts were also examined to determine whether products varied in characteristics that might affect tolerance of milk products by lactose-intolerant subjects . The Lactobacillus sp . isolated from pigs had lower beta-galactosidase activity than did Lactobacillus delbrueckii ssp . bulgaricus strains ATCC 11842 and NCDO 1489 and strains of lactobacilli isolated from yogurt . The beta-galactosidase activity of all strains decreased rapidly once the fermented milk was stored at 4 degrees C . Strain JB10, originating in the stomach contents of the piglets, had properties that were useful for the manufacture of fermented milk products for lactose-intolerant humans . Milk fermented by this strain had a lactose concentration of about 4.0% and contained 6.6 x 10(6) cfu/ml after storage at 4 degrees C for 20 d . Strain JB10 produced a beta-galactosidase that was active at pH 5.5 (35% of the activity at pH 7.0) and was not inhibited by the presence of bile acids in the culture medium . Beta-Galactosidase activity and lactose concentration varied among yogurts.

J Pediatr Gastroenterol Nutr, 1997 Nov, 25(5), 516 - 9
Oral bacterial therapy reduces the duration of symptoms and of viral excretion in children with mild diarrhea; Guarino A et al.; BACKGROUND: Oral administration of live Lactobacillus casei strain GG is associated with the reduction of duration of diarrhea in children admitted to the hospital because of diarrhea . The purposes of this work were to investigate the clinical efficacy of oral administration of Lactobacillus in children with mild diarrhea who were observed as outpatients, and to see whether Lactobacillus GG can reduce the duration of rotavirus excretion . METHODS: Duration of diarrhea was recorded in 100 children seen by family pediatricians and randomly assigned to receive oral rehydration or oral rehydration followed by the administration of lyophilized Lactobacillus casei, strain GG . Rotavirus was looked for in the stools of all children and in those in whom results were positive, stools were examined again 6 days after the onset of diarrhea . RESULTS: In 61 children results were positive for rotavirus and in 39 results were negative . Duration of diarrhea was reduced from 6 to 3 days in children receiving Lactobacillus GG, with a similar pattern in rotavirus-positive and -negative children . Six days after the onset of diarrhea, stools in only 4 out of 31 children that received Lactobacillus GG were positive for rotavirus compared with positive findings in 25 out of 30 control subjects . CONCLUSIONS: Oral administration of Lactobacillus GG is effective in rotavirus-positive and rotavirus-negative ambulatory children with diarrhea . Furthermore, it reduces the duration of rotavirus excretion.

Anal Biochem, 1997 Nov 1, 253(1), 46 - 9
A continuous coupled spectrophotometric assay for tyrosine aminotransferase activity with aromatic and other nonpolar amino acids; Luong TN et al.; A continuous assay for Escherichia coli tyrosine aminotransferase (TATase) that employs Lactobacillus delbrueckii ssp . bulgaricus hydroxyisocaproate dehydrogenase (HO-HxoDH) as a coupling enzyme is described . alpha-Keto acids, including those formed by TATase-catalyzed transamination of l-phenylalanine, l-tyrosine, l-tryptophan, l-methionine, and l-leucine, are converted to the corresponding alpha-hydroxy acids by the auxiliary enzyme . The concomitant reduction of NADH by this enzyme can be followed as a decrease in absorbance at 340 nm . Importantly, HO-HxoDHcatalyzed reduction of alpha-ketoglutarate (alpha-KG), a cosubstrate of TATase required to regenerate the pyridoxal-5'-phosphate cofactor of this enzyme from pyridoxamine-5'-phosphate, is a poor substrate and does not interfere with the assay . The kinetic parameters determined for the transamination of phenylalanine by TATase (kcat = 180 s-1, KM (L-Phe) = 0.56 mM, KM (alpha-KG) = 5 mM) with HO-HxoDH as a coupling enzyme are comparable to those reported in the literature, which were determined by direct monitoring of the formation of phenylpyruvate at 280 nm . This new assay offers the advantages of increased sensitivity and broad substrate specificity .

Curr Microbiol, 1997 Dec, 35(6), 319 - 26
Characteristics and genetic determinants of bacteriocin activities produced by Carnobacterium piscicola CP5 isolated from cheese; Herbin S et al.; Carnobacterium piscicola CP5, isolated from a French mold-ripened soft cheese, produced a bacteriocin activity named carnocin CP5, which inhibited Carnobacterium, Enterococcus and Listeria spp . strains, and among the Lactobacillus spp . only Lactobacillus delbrueckii spp . {24} . The activity was purified by ammonium sulfate precipitation, anion exchange, and hydrophobic interaction chromatography followed by reverse-phase high-performance liquid chromatography (RP-HPLC) . This latter step separated two peaks with anti-listerial activity (CP51 and CP52) . Carnocin CP51 was partially sequenced, and the N-terminal part revealed the presence of the "pediocin-like consensus" sequence-Tyr-Gly-Asn-Gly-Val- . Then, a degenerated 24-mer oligonucleotide probe was constructed from the N-terminal sequence and used to detect the structural gene . It was localized on a plasmid of about 40 kb . Cloning of restriction fragments of this one, followed by DNA sequencing, revealed the presence of the second anti-Listeria bacteriocin gene (CP52) . By comparing sequences in data banks and confirming results with PCR reactions, carnocin CP51 shared homologies with carnobacteriocin BM1, and carnocin CP52 was similar to carnobacteriocin B2, both produced by C . piscicola LV17 {2} . However, carnobacteriocin A from C . piscicola LV17 gene was lacking in C . piscicola CP5, and the two microorganisms have been isolated from different ecological environments: C . piscicola CP5 and C . piscicola LV17 were isolated from soft cheese and vacuum-packed meat respectively . This fact could allow different application perspectives for C . piscicola CP5.

J Bacteriol, 1997 Nov, 179(21), 6657 - 64
Catabolite repression in Lactobacillus casei ATCC 393 is mediated by CcpA; Monedero V et al.; The chromosomal ccpA gene from Lactobacillus casei ATCC 393 has been cloned and sequenced . It encodes the CcpA protein, a central catabolite regulator belonging to the LacI-GalR family of bacterial repressors, and shows 54% identity with CcpA proteins from Bacillus subtilis and Bacillus megaterium . The L . casei ccpA gene was able to complement a B . subtilis ccpA mutant . An L . casei ccpA mutant showed increased doubling times and a relief of the catabolite repression of some enzymatic activities, such as N-acetylglucosaminidase and phospho-beta-galactosidase . Detailed analysis of CcpA activity was performed by using the promoter region of the L . casei chromosomal lacTEGF operon which is subject to catabolite repression and contains a catabolite responsive element (cre) consensus sequence . Deletion of this cre site or the presence of the ccpA mutation abolished the catabolite repression of a lacp::gusA fusion . These data support the role of CcpA as a common regulatory element mediating catabolite repression in low-GC-content gram-positive bacteria.

Eur J Clin Microbiol Infect Dis, 1997 Sep, 16(9), 681 - 4
Lactobacillus species as emerging pathogens in neutropenic patients; Fruchart C et al.; The intensive use of broad-spectrum antibiotics in the context of prolonged and severe neutropenia has contributed to the emergence of unusual pathogens . Four new cases of severe Lactobacillus infections-three of septicemia and one of pneumonia-are reported . They occurred in patients with acute leukemia who had chemotherapy-induced neutropenia . All patients were treated in the same intensive care unit and received the same antimicrobial prophylaxis which included a total bowel decontamination containing vancomycin . The four patients were treated with a combination of intravenous ceftazidime and vancomycin prior to the development of Lactobacillus infection . Improvement in the condition of all patients was obtained with a treatment including penicillin and concurrent recovery of granulopoiesis.

Lett Appl Microbiol, 1997 Oct, 25(4), 295 - 9
Flow cytometric analysis of Lactobacillus plantarum to monitor lag times, cell division and injury; Ueckert JE et al.; Flow cytometry in combination with fluorescent molecular markers 5- (and 6-) carboxyfluorescein succinimidylester (CFSE) and propidium iodide (PI) have been applied to determine lag times, numbers of cell divisions and injury after mild heat (50 degrees C, 5 min) and nisin treatments (0.1 and 1.0 microgram ml-1) of Lactobacillus plantarum . Initial labelling with covalently bound dye CFSE (20 and 100 micrograms ml-1) allowed determination of lag times and cell proliferation for up to eight generations . Double-labelling with CFSE and PI (5 micrograms ml-1) provided additional information about damage levels and distributions within populations . Subpopulations surviving treatment could be identified easily and selectively sorted.

Lett Appl Microbiol, 1997 Oct, 25(4), 233 - 8
Identification and characterization of homofermentative mesophilic Lactobacillus strains isolated from artisan starter-free cheeses; Lopez S et al.; Fifty-six strains of mesophilic lactobacilli from hand-made cheeses made without starters have been isolated, identified and characterized . Of these, 21 strains were classified as Lactobacillus plantarum, 18 as Lact . casei subsp . pseudoplantarum, 10 as Lact . curvatus, five as Lact . casei subsp . casei, and two remained unidentified . The numerical classification of these strains, based on 80 different physiological and morphological characteristics, correlated well with the phenotypic classification . Most of the technologically important traits have been examined in these strains, which will allow the selection of some of them to be tested as adjunct cultures in the manufacture of dairy products.

Lett Appl Microbiol, 1997 Sep, 25(3), 215 - 9
Isolation and characterization of proteinase- and aminopeptidase-deficient mutants of Lactobacillus casei subsp . casei IFPL 731; Fernandez de Palencia P et al.; Proteinase-deficient (Prt-) and aminopeptidase-deficient (Amp-) variants of Lactobacillus casei subsp . casei IFPL 731 were isolated and characterized . The Prt- mutant was isolated from strains that developed poorly on glucose milk agar . The Amp- mutant was isolated on the basis of its inability to hydrolyse L-leucine-beta-naphtylamide . The Prt- variant developed poorly, while in milk the Amp- variant grew at about the same rate as the parental strain . The characterization of aminopeptidase activity in more detail showed that at least two enzymes are involved The results of the present study suggest that the proteolytic system of Lactobacillus casei is subjected to a regulatory system.

J Appl Microbiol, 1997 Sep, 83(3), 307 - 13
Effect of NaCl-tolerant lactic acid bacteria and NaCl on the fermentation characteristics and aerobic stability of silage; Cai Y et al.; NaCl-tolerant lactic acid bacteria (LAB) strains LC-10 (Lactobacillus casei) and LP-15 (Lact . plantarum) and NaCl were used as additives to sorghun (Sorghum bicolor) . Numbers of LAB were significantly (P < 0.05) higher in all the additive-treated silages than in the control silage at an early stage of ensiling . During the fermentation process, addition of NaCl or LAB effectively inhibited the growth of aerobic bacteria and clostridia, but not yeasts . All the additive-treated silages had significantly (P < 0.05) lower pH, ammonia nitrogen content, dry matter loss and gas production but significantly (P < 0.05) higher lactic acid content and residual water soluble carbohydrates compared with the control silage . The improvement in silage quality was in the order: LAB > NaCl > control . Yeast counts were high in all additive-based silages and they increased during the exposure of the silages to air . As a result, these silages suffered aerobic deterioration, whereas the control silage was stable . The results confirmed that the NaCl or LAB improved fermentation quality but did not prevent aerobic deterioration of the silage.

Epidemiology, 1997 Nov, 8(6), 612 - 4
Condoms and urinary tract infections: is nonoxynol-9 the problem or the solution?
Steiner MJ, Cates W Jr.
PIP: The use of condoms lubricated with nonoxynol-9 has been associated, in one case-control study, with an increased risk of urinary tract infection (UTI) and, in another, with a reduced risk of UTI . Despite the lack of research on the effects of nonoxynol-9, the US Surgeon General has recommended the addition of at least 65 mg of the spermicide with condoms . Especially in high doses or with frequent application, nonoxynol-9 may cause vaginal or urethral irritation . Preliminary studies suggest it may also change the character of vaginal fluids, alter the capacity of different organisms to bind to the vaginal epithelium, and suppress Lactobacillus growth without influencing Escherichia coli growth . Since neither case-control study provided evidence of an increased risk of UTI associated with the use of lubricated condoms without nonoxynol-9, promotion of nonspermicidal lubricated condoms remains the most feasible approach to the prevention of pregnancy and sexually transmitted diseases . Needed are more well-designed prospective studies to assess the risk factors for UTI--a major cause of morbidity among US women .

Enzyme Microb Technol, 1997 Nov 1, 21(6), 413 - 20
Maltose phosphorylase from Lactobacillus brevis: purification, characterization, and application in a biosensor for ortho-phosphate; Huwel S et al.; With the goal to obtain maltose phosphorylase as a tool to determine ortho-phosphate, the enzyme from Lactobacillus brevis was purified to 98% by an expeditious FPLC-aided procedure which included anion exchange chromatography, gel filtration, and hydroxyapatite chromatography . The native maltose phosphorylase had a molecular mass of 196 kDa and consisted of two 88 kDa subunits . In isoelectric focusing two isoforms with pI values of 4.2 and 4.6 were observed . Maximum enzyme activity was obtained at 36 degrees C and pH 6.5 and was independent of pyridoxal 5'-phosphate . The apparent K(m) values with maltose and phosphate as substrates were 0.9 mmol l-1 and 1.8 mmol l-1, respectively . Maltose phosphorylase could be stored in 10 mM phosphate buffer pH 6.5 at 4 degrees C with a loss of activity of only 7% up to 6 months . The stability of the enzyme at high temperatures was enhanced significantly using additives like phosphate, citrate, and imidazole . The purified maltose phosphorylase was used as key enzyme in a phosphate sensor consisting of maltose phosphorylase and glucose oxidase . A detection limit of 0.1 microM phosphate was observed and the sensor response was linear in the range between 0.5 and 10 microM.

Protein Eng, 1997 Jul, 10(7), 815 - 26
Effects of single-residue substitutions on negative cooperativity in ligand binding to dihydrofolate reductase; Basran J et al.; The effects of six amino acid substitutions in Lactobacillus casei dihydrofolate reductase, predominantly in the coenzyme binding site, on catalysis and on the negative cooperativity between NADPH and tetrahydrofolate binding have been determined . Replacement of Leu62, His64 or Leu54 by alanine has no effect on kcat, and produces only modest changes in negative cooperativity . Alanine substitution of His77, which interacts indirectly with the coenzyme adenine ring, leads to a doubling of the negative cooperativity and a consequent doubling of kcat . Replacement of Arg43, which interacts with the coenzyme 2'-phosphate, by alanine, or of Trp21, which interacts with the coenzyme nicotinamide ring, by histidine leads to a 20-100-fold decrease in negative cooperativity . In both mutants there is a decrease in kcat; isotope effects show that product release is largely rate-limiting in R43A, whereas in W21H hydride ion transfer is rate-limiting . 1H NMR has been used to obtain information on the extent of the structural changes produced by the substitutions . This varies from very local effects in H64A to very widespread effects in W21H . These changes are used as the basis for discussion of the mechanisms of the functional effects of the various substitutions . It is suggested that residues in helix C, beta-strand 3 and the beta3-beta4 loop may be involved in the transmission of effects between the coenzyme and substrate binding sites.

J Bacteriol, 1997 Oct, 179(19), 6208 - 12
Peptidoglycan structure of Lactobacillus casei, a species highly resistant to glycopeptide antibiotics; Billot-Klein D et al.; The structure of the peptidoglycan of Lactobacillus casei ATCC 393, a species highly resistant to glycopeptide antibiotics, was examined . After digestion, 23 muropeptides were identified; monomers represented 44.7% of all muropeptides, with monomer tetrapeptides being the major ones . Fifty-nine percent of the peptidoglycan was O-acetylated . The cross-bridge between D-alanine and L-lysine consisted of one asparagine, although aspartate could be found in minor quantities . Since UDP-MurNAc-tetrapeptide-D-lactate is the normal cytoplasmic precursor found in this species, monomer tetrapeptide-lactate was expected to be found . However, such a monomer was found only after exposure to penicillin, suggesting that penicillin-sensitive D,D-carboxypeptidases were very active in normal growing cells.

S Afr Med J, 1997 Aug, 87(8), 1011 - 3
Do vaginal lactobacilli prevent preterm labour?
Kotze IR, Odendaal HJ, Joubert JJ.
OBJECTIVE: To determine the prevalence of Lactobacillus spp . in vaginal flora during pregnancy and to assess the protective effects of lactobacilli against preterm labour . DESIGN: Cross-sectional analysis of Lactobacillus spp . in the vaginal flora of the pregnant coloured population of the Western Cape . PARTICIPANTS: A total of 480 consecutive pregnant women, aged 13-48 years, seen at their first visit to the Tygerberg Hospital antenatal clinic . MAIN OUTCOME MEASURES: Preterm labour, i.e . before 34 and 37 weeks' gestation, premature rupture of membranes, intra-uterine growth retardation and perinatal deaths . RESULTS: A total of 163 patients had negative cultures and 317 positive cultures for lactobacilli, aerobes or both . Delivery before 37 weeks occurred in 18% and 20% of the two groups, respectively . Lactobacillus only was cultured from 116 patients and Lactobacillus and/or other aerobes from 201 patients . Preterm labour occurred in 20% of the first group and in 19% of the second group . The perinatal outcome in patients from whom lactobacilli only were cultivated did not differ from patients from whom other aerobes and lactobacilli or other aerobes only were cultured . CONCLUSION: In patients at high risk for preterm labour, the presence of lactobacilli in the vagina does not seem to play a protective role.

Crit Rev Biotechnol, 1997, 17(3), 227 - 72
Plasmids in Lactobacillus; Wang TT et al.; This review describes Lactobacillus plasmids on distribution, structure, function, vector construction, vector stability, application, and prospective . About 38% of species of the genus Lactobacillus were found to contain plasmids with different sizes (from 1.2 to 150 kb) and varied numbers (1 or more) . Some Lactobacillus plasmids with small sizes were highly similar to those of single strand plasmids from other Gram-positive bacteria . The extensive sequence homologies of plus origins, replication initiation proteins, minus origins, cointegration sites, and the presence of single strand intermediates supported the fact that these small Lactobacillus plasmids replicate with a rolling-circle replication mechanism . Some Lactobacillus plasmid replicons were of broad host range that could function in other Gram-positive bacteria, and even in Escherichia coli, while replicons of other Gram-positive bacteria also function in Lactobacillus . Although most Lactobacillus plasmids are cryptic, some plasmid-encoded functions have been discovered and applied to vector construction and Lactobacillus identification, detection, and modification.

Gene, 1997 Sep 15, 197(1-2), 137 - 45
Functional and structural features of the holin HOL protein of the Lactobacillus plantarum phage phi gle: analysis in Escherichia coli system; Oki M et al.; Lactobacillus plantarum phage phi gle has two consecutive cell lysis genes hol-lys (Oki et al., 1996b) . In the present study, functional and structural properties of the hol protein (Hol) were characterized in Escherichia coli . Electron microscopic examinations showed that hol under plac in E . coli XL1-Blue injured the inner membrane to yield empty ghost cells with the bulk of the cell wall undisturbed . Northern blot analysis indicated that hol-lys genes under plac were co-transcribed, although the amount of hol transcript was larger than that of lys, ceasing via an apparently rho-independent terminator just downstream of hol . However, deletion and/or fusion experiments suggested that: (1) the N-terminal half of phi gle Hol composed of three putative transmembrane domains may be responsible for interaction with membrane; (2) the N-terminal end (five amino acids) seems nonessential; and (3) the C-terminal half containing charged amino acids appears to be involved in proper hol function . These results suggest that phi gle Hol is a member of the lambdoid holin family, but divergent in several properties from lambda holin.

Mol Microbiol, 1997 Aug, 25(4), 695 - 705
Replacement of isoleucine-47 by threonine in the HPr protein of Streptococcus salivarius abrogates the preferential metabolism of glucose and fructose over lactose and melibiose but does not prevent the phosphorylation of HPr on serine-46; Gauthier M et al.; Phosphorylation of HPr on a serine residue at position 46 (Ser-46) by an ATP-dependent protein kinase has been reported in several Gram-positive bacteria, and the resulting intermediate, HPr(Ser-P), has been shown to mediate inducer exclusion in lactococci and lactobacilli and catabolite repression in Bacillus subtilis and Bacillus megaterium . We report here the phenotypic properties of an isogenic spontaneous mutant (G22.4) of Streptococcus salivarius ATCC 25975, in which a missense mutation results in the replacement of isoleucine at position 47 (Ile-47) by threonine (Thr) in HPr . This substitution did not prevent the phosphorylation of HPr on Ser-46, nor did it impede the phosphorylation of HPr on His-15 by EI or the transfer of the phosphoryl group from HPr(His-P) to other PTS proteins . However, the 147T substitution did perturb, in glucose-grown but not in galactose-grown cells, the cellular equilibrium between the various forms of HPr, resulting in an increase in the amount of free HPr at the expense of HPr(His-P)(Ser-P); the levels of HPr(His-P) and HPr(Ser-P) were not affected . Growth on melibiose was virtually identical for the wild-type and mutant strains, whereas the generation time of the mutant on the other sugars tested (glucose, fructose, mannose, lactose and galactose) increased 1.2- to 1.5-fold . The preferential metabolism of PTS sugars (glucose and fructose) over non-PTS sugars (lactose and melibiose) that is observed in wild-type cells was abolished in cells of mutant G22.4 . Moreover, alpha- and beta-galactosidases were derepressed in glucose- and fructose-grown cells of the mutant . The data suggest that HPr regulates the preferential metabolism of PTS sugars over the non-PTS sugars, lactose and melibiose, through the repression of the pertinent catabolic genes . This HPr-dependent repression, however, seems to occur solely when cells are growing on a PTS sugar.

Bone Marrow Transplant, 1997 Sep, 20(6), 479 - 83
Impact of conditioning regimens on salivary function, caries-associated microorganisms and dental caries in children after bone marrow transplantation . A 4-year longitudinal study; Dahllof G et al.; Salivary function, dental caries and caries-associated salivary microorganisms were investigated in children undergoing BMT during a 4-year longitudinal study . Fourteen children were conditioned with CY and TBI and 12 with CY with or without BU . Four years after BMT the mean salivary secretion rate was 1.3 +/- 0.7 ml/min in the chemotherapy group, compared to 0.7 +/- 0.5 in the TBI/CY group (P < 0.05) . The mean salivary secretion rate fell from 0.9 +/- 0.5 ml/min before TBI to 0.2 +/- 0.1 after 3 months (P < 0.01), 0.3 +/- 0.3 ml/min after 6 months (P < 0.01) and 0.5 +/- 0.6, 1 year after TBI (P < 0.05) . Mean reduction in stimulated salivary flow 3 months after TBI was 78% in the TBI/CY group compared to 36% in the chemotherapy group (P < 0.05) . Children conditioned with chemotherapy showed an increased salivary flow compared to baseline; this was not found in TBI-treated children, suggesting that damage to the salivary glands may be permanent . Four years after BMT, children conditioned with TBI had significantly higher counts of mutans streptococci (P < 0.05) and lactobacilli (P < 0.01) compared to age-matched controls . However, the prevalence of dental caries did not differ between children conditioned with TBI, chemotherapy and healthy controls.

Vet Med (Praha), 1997 Aug, 42(8), 217 - 24
Stimulation of cell defense mechanism of bovine endometrium by temporal colonization with selected strains of lactobacilli; Kummer V et al.; The aim of the experiments was to assess the response to topical administration of selected live strains of lactobacilli of the cells responsible for the resistance of bovine endometrium . Experimental cows (n = 8) at 8 to 12 days of the estrous received one intrauterine dose of 20 ml of a suspension of lactobacilli in 1% glucose solution . Group I (n = 4) was treated with the strain Lactobacillus spp . G 013 (5.5 x 10(8) CFU/ml) and Group II (n = 4) with the strain Lactobacillus casei CCM 1753 (1.2 x 10(8) CFU/ml) . Control cows (n = 4) received 20 ml of 1% glucose solution . Samples of endometrial tissue were obtained by biopsy or from slaughtered cows on post-treatment days 5 or 6 and/or 10 or 12 . Colonization of the uterine cavity with lactobacilli for up to 12 days was confirmed by bacteriological examination and scanning electron microscopy . Highly significant increases (P < 0.01) were found in numbers of all cell types under study . The pronounced cellular infiltration of endometrium was mostly due to the accumulation of mononuclear cells, particularly lymphocytes forming often indistinctly demarcated lymphoid nodules . Also marked was the infiltration of mast cells and macrophages . The cellular infiltration of endometrium persisted still on post-treatment day 12 . No signs of alteration of epithelial cells were observed . No principal differences in the effects on endometrium were found between the two lactobacilli strains . The proved stimulatory effect of lactobacilli on endometrial cell defense mechanisms demonstrated in our experiments and inhibitory effects of the former on the growth of pathogenic microorganisms are promising for practical application in the prevention and alternative therapy of bovine endometritis.

J Dairy Sci, 1997 Sep, 80(9), 1965 - 70
Antimutagenic effects of milk fermented by Lactobacillus helveticus L89 and a protease-deficient derivative; Matar C et al.; The antimutagenic effects of whey, acetone extracts, and protein fractions isolated from milk that had been fermented by Lactobacillus helveticus L89 were investigated using the mutagen 4-nitroquinoline-N'-oxide in the Ames test (Salmonella typhimurium TA 100) . Fermented milk significantly inhibited mutagenesis induced by 4-nitroquinoline-N'-oxide . However, milk fermented by a nonproteolytic variant of the same strain showed no inhibitory effects . Results were similar for the whey fractions and acetone extracts of the fermented milks . After fermentation, milk proteins were fractionated by size-exclusion HPLC and were tested for antimutagenicity . The fraction showing the greatest activity was further analyzed by reverse-phase HPLC . Our results indicate that antimutagenic compounds are produced in milk during fermentation by L . helveticus, and the release of peptides is one possible contributing mechanism.

J Dairy Sci, 1997 Sep, 80(9), 1955 - 8
Influence of bile on beta-galactosidase activity and cell viability of Lactobacillus reuteri when subjected to freeze-drying; de Valdez GF et al.; The effect of bile on beta-galactosidase activity and cell viability was investigated using two strains of Lactobacillus reuteri that were subjected to freeze-drying . In the presence of 0.15% oxgall, beta-galactosidase activity of the whole cells was significantly increased . After lyophilization, the cultures that had been treated with oxgall showed a low survival rate without changes in beta-galactosidase activity . The poor resistance of the cells to damage from freeze-drying might be related to the presence of membranous structures containing simple folds and buds of the cell membrane, as was observed by transmission electron microscopy.

J Dairy Sci, 1997 Sep, 80(9), 1949 - 54
Maturation factor for the activation process of an extracellular proteinase in Lactobacillus helveticus CP790; Yamamoto N et al.; A maturation factor that was needed for activation of an extracellular proteinase was partially purified from Lactobacillus helveticus CP790 by DEAE-Sepharose column chromatography, followed by gel filtration using HPLC . The protein had the ability to accelerate the conversion of proproteinase to active enzyme but had no proteolytic activity toward casein that had been treated with fluorescein isothiocyanate . The proteinase activities in the proproteinase fraction and the maturation protein fraction were not affected by preincubation of either fraction separately . However, when the mixture of the proproteinase and the maturation protein was incubated, the conversion of the proproteinase to active enzyme was accelerated, and proteinase activity increased . The production of some proteins that were specific to the active fractions was highest at the midlog phase of cell growth, which corresponded to the period of maximum proteinase activity . The results suggest that the proproteinase is activated to the mature enzyme not by an autocatalytic process but by the help of a maturation protein.

Int J Food Microbiol, 1997 Jul 22, 37(2-3), 155 - 62
Antibacterial activity of selected fatty acids and essential oils against six meat spoilage organisms; Ouattara B et al.; The antibacterial activity of selected fatty acids and essential oils was examined against two gram-negative (Pseudomonas fluorescens and Serratia liquefaciens) and four gram-positive (Brochothrix thermosphacta, Carnobacterium piscicola, Lactobacillus curvatus, and Lactobacillus sake) bacteria involved in meat spoilage . Various amounts of each preservative were added to brain heart infusion or MRS (deMan, Rogosa and Sharpe) agars, and the minimum inhibitory concentration was determined for each organism . Essential oils were analysed by gas-liquid chromatography to determine the concentration of selected components commonly found in spices . B . thermosphacta, P . fluorescens and S . liquefaciens were not affected by fatty acids, and generally overcame the inhibitory effect of essential oils after 24 h of exposure . Among the fatty acids, lauric and palmitoleic acids exhibited the greatest inhibitory effect with minimum inhibitory concentrations of 250 to 500 micrograms/ml, while myristic, palmitic, stearic and oleic acids were completely ineffective . For essential oils, clove, cinnamon, pimento, and rosemary were found to be the most active . The 1/100 dilution of those oils inhibited at least five of the six tested organisms . A relationship was found between the inhibitory effect of essential oils and the presence of eugenol and cinnamaldehyde.

Clin Infect Dis, 1997 Sep, 25 Suppl 2, S123 - 6
Vaginal microflora in postmenopausal women who have not received estrogen replacement therapy; Hillier SL et al.; We studied the vaginal microflora of 73 postmenopausal women who had never received estrogen replacement therapy . The median age of these women was 67 years, and none of them had bacterial vaginosis . Lactobacilli were detected in 36 (49%) of these women at a mean concentration of 10(5.7) cfu/g of vaginal fluid . H2O2-producing lactobacilli were recovered from 38% of the women . Some of the other organisms that were recovered, including Gardnerella vaginalis (27% of the women), Ureaplasma urealyticum (13%), Candida albicans (1%), and Prevotella bivia (33%), were less frequently isolated from postmenopausal women than from women of reproductive age, while coliforms (41%) were recovered at higher frequencies . Lactobacilli, yeasts, and bacterial vaginosis-associated bacteria are less commonly part of the vaginal microflora in postmenopausal women than in women of reproductive age, which may explain the decrease in the incidence of bacterial vaginosis and yeast vaginitis among these women.

Int J STD AIDS, 1997 Oct, 8(10), 603 - 8
Sex, thrush and bacterial vaginosis; Hay PE et al.; Bacterial vaginosis (BV) is the most common cause of vaginal discharge in women of childbearing age . In some women it shows a relapsing and remitting course with apparently spontaneous onset and resolution . There are intermediate patterns of vaginal flora in which lactobacilli and other species co-exist . We asked women with recurrent BV to prepare vaginal smears daily, and to record symptoms, time of menstruation, sexual activity and use of douches or medication . We Gram-stained the smears and assigned a Nugent score for BV, and noted the presence of candida, pus cells, sperm and blood . Eighteen women collected daily vaginal smears for up to 10 months . Forty months of slides were collected in total . Bacterial vaginosis arose spontaneously on 23 occasions . We saw candida arise 11 times . Bacterial vaginosis appeared after candida on 9 of these 11 episodes . We saw BV regress spontaneously 13 times . Nine of these resolutions occurred within 48 h of unprotected sexual intercourse: BV only arose on one occasion within 48 h of unprotected intercourse . The intermediate pattern was seen for up to 10 days, and occurred as BV began or resolved in some women, and sometimes resolved without developing into BV . Bacterial vaginosis arose most often in the first 7 days of a menstrual cycle, and resolved spontaneously most often in mid-cycle . In women with recurrent BV, BV arises most often around the time of menstruation and resolves spontaneously in mid-cycle . Recurrences often follow an episode of candidiasis, and BV often regresses after unprotected sexual intercourse.

Ann Allergy Asthma Immunol, 1997 Sep, 79(3), 229 - 33
Immune and clinical impact of Lactobacillus acidophilus on asthma; Wheeler JG et al.; BACKGROUND: Animal and human studies have suggested that yogurt containing live active bacteria leads to improved immune and clinical responses . Specific benefits of yogurt containing L . acidophilus on allergic asthma have been hypothesized but not studied . METHODS: In a crossover double-blinded design, the effect of live active yogurt (225 g twice daily) with or without L . acidophilus was studied in 15 adult patients with moderate asthma . Immune and clinical parameters were measured before and after the two 1-month crossover phases . RESULTS: No significant changes were noted in peripheral cell counts, IgE, IL-2, or IL-4 when comparing the two diets to each other . Concanvalin A-stimulated lymphocytes from patients who consumed yogurt containing L . acidophilus produced borderline elevated interferon gamma levels (P = .054) . No differences were noted in mean daily peak flows or changes in spirometric values . Quality of life indices were unchanged when comparing the two groups . CONCLUSIONS: Yogurt containing L . acidophilus generated trends in the increase in interferon gamma and decreased eosinophilia; however, we were unable to detect changes in clinical parameters in asthma patients in association with these modest immune changes.

Zh Mikrobiol Epidemiol Immunobiol, 1997 May-Jun, (3), 89 - 91
{The antagonistic action of lactobacilli on Helicobacter pylori}; Bazhenov LG et al.; The antagonistic activity of 9 strains of the genus Lactobacillus with respect to 25 H . pylori clinical cultures was studied with the use of the original method of ring blocks . The presence of high antagonistic activity of strains L . casei 925, L . plantarum 8 RA-3, L . fermentum BL-96 and L . 90265 was established . The newly developed method of the determination of antagonistic activity with respect to H . pylori, taking into account the biological features of this organism, was found to be convenient for work, precise and giving reproducible results.

Fiziol Zh, 1997, 43(3-4), 106 - 15
{The current concepts of the influence of lactobacilli on the immune system of the human body}; Kostiuk OP et al.; The review summarizes experimental and clinical data about the influence of Lactobacillus on the immune system . A conclusion is made that the effect of Lactobacillus is a multifactor process . After entering the intestinal tract live microorganisms or biologically active substances produced by them may activate specific and nonspecific systems of microorganism protection . Experimental and clinical data about the action of Lactobacillus as adjuvants to the humoral immune response are presented . The mechanisms of anticancerogenic action of Lactobacillus and their cell wall components are analyzed in detail . The prospects for the use of Lactobacillus as probiotics in medicine are considered . The conclusion about positive value of the multifactor action of these microorganisms on the human immune system is made, since no negative effects are evoked by the discussed mechanisms of specific effect of Lactobacillus . This opens wide possibilities for the development of application schemes of probiotics from lactobacillus for the stimulation of several functions of the immune system, creation a new forms of antitumor drugs and combination of them with oral vaccines for improving their immunogenicity.

Cryobiology, 1997 Aug, 35(1), 31 - 40
Effect of added carbohydrates on membrane phase behavior and survival of dried Lactobacillus plantarum; Linders LJ et al.; The relation between the protective effect of externally added carbohydrates on Lactobacillus plantarum cells during air-drying and the phase behavior of cell membranes was studied . The residual activity after drying could be improved from 44% in the control to 79 and 66% after the addition of sorbitol and maltose, respectively, whereas trehalose addition resulted in a residual activity of 30% . Membrane phase transition temperatures (Tm) were determined in intact hydrated and dry cells, using Fourier transform infrared spectroscopy . The Tm of hydrated cells was 4 degrees C, increasing to only 20 degrees C after drying . Because endogenous soluble sugars were absent, this phase behavior is attributed to the structure of the predominant phospholipids, PG and lysyl-PG . The restricted increase of Tm is held responsible for the survival of part of the cells . The added maltose, trehalose, and sorbitol did not influence Tm in vivo . We suggest that the effective carbohydrates act through their free radical scavenging activity and not by direct interaction with the polar lipid headgroups.

FEMS Microbiol Rev, 1997 Jul, 20(3-4), 379 - 89
Ecofunctional enzymes of microbial communities in ground water; Fliermans CB et al.; Biolog technology was initially developed as a rapid, broad spectrum method for the biochemical identification of clinical microorganisms . Demand and creative application of this technology has resulted in the development of Biolog plates for Gram-negative and Gram-positive bacteria, for yeast and Lactobacillus sp . Microbial ecologists have extended the use of these plates from the identification of pure culture isolates to a tool for quantifying the metabolic patterns of mixed cultures, consortia and entire microbial communities . Patterns that develop on Biolog microplates are a result of the oxidation of the substrates by microorganisms in the inoculum and the subsequent reduction of the tetrazolium dye to form a color in response to detectable reactions . Depending upon the functional enzymes present in the isolate or community one of a possible 4 x 10(28) patterns can be expressed . The patterns were used to distinguish the physiological ecology of various microbial communities present in remediated groundwater . The data indicate that one can observe differences in the microbial community among treatments of bioventing, 1% and 4% methane injection, and pulse injection of air, methane and nutrients both between and among wells . The investigation indicates that Biolog technology is a useful parameter to measure the physiological response of the microbial community to perturbation and allows one to design enhancement techniques to further the degradation of selected recalcitrant and toxic chemicals . Further it allows one to evaluate the recovery of the microbial subsurface ecosystem after the perturbations have ceased . We propose the term 'ecofunctional enzymes' (EFE) as the most descriptive and useful term for the Biolog plate patterns generated by microbial communities . We offer this designation and provide ecological application in an attempt to standardize the terminology for this relatively new and unique technology.

APMIS, 1997 Aug, 105(8), 643 - 9
Prevention of onset in an insulin-dependent diabetes mellitus model, NOD mice, by oral feeding of Lactobacillus casei; Matsuzaki T et al.; The effect of Lactobacillus casei (LC) on the onset of diabetes in an insulin-dependent diabetes mellitus model, nonobese diabetic (NOD) mice, were examined . From the age of 4 weeks, female NOD mice were fed a diet of either standard laboratory chow (n = 12) or the same chow containing 0.05% weight heat-killed cells of LC (n = 12), and the onset of diabetes was thereafter recorded . The incidence of diabetes in the control group (10/12) was significantly higher than that in the LC-treated group (3/12) (p < 0.01) . Pathological analysis in the LC-treated group revealed strong inhibition of the disappearance of insulin-secreting beta cells in Langerhans islets caused by autoimmune disease . The proportion of CD45R+ B-cells in the spleen was increased and that of CD8+ T-cells in spleen cells was decreased in the LC-treated group . Analysis of cytokine production revealed lower interferon-gamma production in the LC-treated group compared to the control group, while the interleukin (IL)-2 production was higher . The levels of IL-4, IL-5, IL-6 and IL-10 in the LC-treated group were somewhat higher than in the control group . Taken together, these findings clearly demonstrated that oral feeding of LC to NOD mice effectively inhibited the occurrence of diabetes and regulated the host immune response.

APMIS, 1997 Aug, 105(8), 637 - 42
Effect of oral administration of Lactobacillus casei on alloxan-induced diabetes in mice; Matsuzaki T et al.; The effect of Lactobacillus casei (LC) on the onset of alloxan (AXN)-induced diabetes in 7-week-old BALB/c mice were examined . It was observed that the mice given a diet containing 0.1% or 0.05% LC or orally administered LC showed significantly decreased incidence of diabetes induced by intravenous injection of AXN and that the plasma glucose level was slightly lower than that in the control group . The body weight in the LC-treated groups was higher than that in the control group, although the food intake weights were almost the same . Pathological analysis revealed that the AXN-induced disappearance of insulin-secreting beta-cells in the islets of Langerhans was strongly inhibited in the LC-treated groups . It was also shown that the serum nitric oxide level was maintained at a normal level in LC-treated mice, whereas the level in the control group was increased by AXN administration . Taken together, these findings suggest that oral administration of LC to AXN-treated BALB/c mice contributed to the reduction of diabetes and the increase in plasma glucose level.

Prikl Biokhim Mikrobiol, 1997 May-Jun, 33(3), 305 - 9
{Antimicrobial and immunomodulatory activities of Lactobacillus acidophilus Ke-10}; Zalashko MV et al.; In addition to a high antimicrobial activity toward infective agents of some diseases of the human gastrointestinal tract, Lactobacillus acidophilus Ke-10 also had an immunomodulatory effect in physiological experiments both in vivo and in vitro . This strain of lactic acid bacteria was found to be able to restore the proliferation reaction of lymphocytes and their capacity to produce interleukin-2 (IL-2) in rats with a model radiation-induced immune deficiency.

Biochim Biophys Acta, 1997 Aug 16, 1347(2-3), 127 - 39
Unusual lipid composition of the gram-negative, freshwater, stalked bacterium Caulobacter bacteroides NP-105; Batrakov SG et al.; The extractable lipids of the gram-negative, stalked, freshwater bacterium Caulobacter bacteroides NP-105 account for about 9.5% by weight of dry cells, polar lipids comprising up to 95% of the total . The polar lipids consist of five glycolipids, namely, 1,2-diacyl-3-alpha-D-glucopyranosyl-sn-glycerol (I) (34% of the total), 1,2-diacyl-3-alpha-D-{6'-(1",2"-diacyl-sn-glycero-3-phospho)}glucopyranosyl-sn-glycerol (II) (7%), 1,2-diacyl-3-a-D-glucuronopyranosyl-sn-glycerol (III) (17%), 1,2-diacyl-3-alpha-D-(6'-sulfo)quinovopyranosyl-sn-glycerol (V) (9%), and 1,2-diacyl-3-alpha-D-{4'-(alpha-D-glucopyranosyl)} glucuronopyranosyl-sn-glycerol (VI) (28%), and one glycerophospholipid, 1,2-diacyl-sn-glycero-3-phosphoglycerol (IV) (5%) . The main fatty acyls of the lipids are n-16:0, cis-18:1 omega7, and cis-11,12-methyleneoctadecanoic (lactobacillic) acid residue . Of the 6 lipids listed, only 3 (I, IV, and V) can be treated as widely encountered . However, sulfonic glycolipid V is a characteristic lipid component of photosynthetic organisms rather than non-photosynthetic ones . Phosphatidyl derivatives of glycosyldiacylglycerols of type II normally occur in gram-positive bacteria, among gram-negative bacteria they have been revealed only in two species of the Pseudomonas genus . Glucuronosyl and alpha-glucosyl-a-glucuronosyl diacylglycerols such as III and VI, respectively, are very rare lipids, the latter being found so far only in a Streptomyces strain.

Appl Environ Microbiol, 1997 Sep, 63(9), 3628 - 36
Interactions of nisin and pediocin PA-1 with closely related lactic acid bacteria that manifest over 100-fold differences in bacteriocin sensitivity; Bennik MH et al.; The natural variation in the susceptibilities of gram-positive bacteria towards the bacteriocins nisin and pediocin PA-1 is considerable . This study addresses the factors associated with this variability for closely related lactic acid bacteria . We compared two sets of nonbacteriocinogenic strains for which the MICs of nisin and pediocin PA-1 differed 100- to 1,000-fold: Lactobacillus sake DSM20017 and L . sake DSM20497 and Pediococcus dextrinicus and Pediococcus pentosaccus . Strikingly, the bacteriocin-sensitive and -insensitive strains showed a similar concentration-dependent dissipation of their membrane potential (delta psi) after exposure to these bacteriocins . The bacteriocin-induced dissipation of delta psi below the MICs for the insensitive strains did not coincide with a reduction of intracellular ATP pools and glycolytic rates . This was not observed with the sensitive strains . Analysis of membrane lipid properties revealed minor differences in the phospho- and glycolipid compositions of both sets of strains . The interactions of the bacteriocins with strain-specific lipids were not significantly different in a lipid monolayer assay . Further lipid analysis revealed higher in situ membrane fluidity of the bacteriocin-sensitive Pediococcus strain compared with that for the insensitive strain, but the opposite was found for the L . sake strains . Our results provide evidence that the association of bacteriocins with the cell membrane and their subsequent insertion take place in a similar way for cells that have a high or a low natural tolerance towards bacteriocins . For insensitive strains, overall membrane constitution rather than mere membrane fluidity may preclude the formation of pores with sufficient diameters and lifetimes to ultimately cause cell death.

Appl Environ Microbiol, 1997 Sep, 63(9), 3438 - 43
Biochemical and molecular characterization of PepR, a dipeptidase, from Lactobacillus helveticus CNRZ32; Shao W et al.; A dipeptidase with prolinase activity from Lactobacillus helveticus CNRZ32, which was designated PepR, was purified to gel electrophoretic homogeneity and characterized . The NH2-terminal amino acid sequence of the purified protein had 96% identity to the deduced NH2-terminal amino acid sequence of the pepR gene, which was previously designated pepPN, from L . helveticus CNRZ32 . The purified enzyme hydrolyzed Pro-Met, Thr-Leu, and Ser-Phe as well as dipeptides containing neutral, nonpolar amino acid residues at the amino terminus . Purified PepR was determined to have a molecular mass of 125 kDa with subunits of 33 kDa . The isoelectric point of the enzyme was determined to be 4.5 . The optimal reaction conditions, as determined with Pro-Leu as substrate, were pH 6.0 to 6.5 and 45 to 50 degrees C . The purified PepR had a Km of 4.9 to 5.2 mM and a Vmax of 260 to 270 mumol of protein per min/mg at pH 6.5 and 37 degrees C . The activity of purified PepR was inhibited by Zn2+ but not by other cations or cysteine, serine, aspartic, or metal-containing protease inhibitors or reducing agents . Results obtained by site-directed mutagenesis indicated that PepR is a serine-dependent protease . Gene replacement was employed to construct a PepR-deficient derivative of CNRZ32 . This mutant did not differ from the wild-type strain in its ability to acidify milk . However, the PepR-deficient construct was determined to have reduced dipeptidase activity compared to the wild-type strain with all dipeptide substrates examined.

Carbohydr Res, 1997 Aug 7, 302(3-4), 197 - 202
Lactobacillus helveticus Lh59 secretes an exopolysaccharide that is identical to the one produced by Lactobacillus helveticus TN-4, a presumed spontaneous mutant of Lactobacillus helveticus TY1--2; Stingele F et al.; Lactobacillus helveticus Lh59 produces a high-molecular-mass exopolysaccharide (> or = 2 x 10(6) Da) when cultured in skimmed milk . Compositional analysis, methylation analysis and NMR experiments (1H and 13C) recorded from the native polysaccharide as well as from oligosaccharides released by partial acid hydrolysis, allowed the complete structural determination of this polysaccharide, which consists of the following hexasaccharide repeating unit: {symbol: see text} This structure is identical to the one of an EPS produced by L . helveticus TN-4, which was claimed to be a spontaneous mutant of strain TY1-2.

J Bacteriol, 1997 Sep, 179(17), 5391 - 7
Regulation of expression of the Lactobacillus pentosus xylAB operon; Lokman BC et al.; The xylose cluster of Lactobacillus pentosus consists of five genes, two of which, xylAB, form an operon and code for the enzymes involved in the catabolism of xylose, while a third encodes a regulatory protein, XylR . By introduction of a multicopy plasmid carrying the xyl operator and by disruption of the chromosomal xylR gene, it was shown that L . pentosus xylR encodes a repressor . Constitutive expression of xylAB in the xylR mutant is repressed by glucose, indicating that glucose repression does not require XylR . The xylR mutant displayed a prolonged lag phase compared to wild-type bacteria when bacteria were shifted from glucose to xylose medium . Differences in the growth rate in xylose medium at different stages of growth are not correlated with differences in levels of xylAB transcription in L . pentosus wild-type or xylR mutant bacteria but are positively correlated in Lactobacillus casei with a plasmid containing xylAB . Glucose repression was further investigated with a ccpA mutant . An 875-bp internal fragment of the ccpA gene of L . pentosus was isolated by PCR and used to construct a ccpA knockout mutant . Transcription analysis of L . pentosus xylA showed that CcpA is involved in glucose repression . CcpA was also shown to be involved in glucose repression of the alpha-amylase promoter of Lactobacillus amylovorus by demonstrating that glucose repression of the chloramphenicol acetyltransferase gene under control of the alpha-amylase promoter is strongly reduced in the L . pentosus ccpA mutant strain.

J Nutr, 1997 Sep, 127(9), 1772 - 5
Compartmentation of folate metabolism in rat pancreas: nitrous oxide inactivation of methionine synthase leads to accumulation of 5-methyltetrahydrofolate in cytosol; Horne DW et al.; Folate-dependent one-carbon metabolism and methylation reactions have been implicated in the secretory function of the pancreas . Because vitamin B-12 deficiency perturbs folate metabolism, we determined the effects of nitrous oxide inactivation of methionine synthase on the compartmentation of folate metabolism in rat pancreas . Rats were exposed to an atmosphere of nitrous oxide and oxygen (80 and 20%, respectively) for 18 h; control rats breathed air . Folate coenzyme concentrations were determined by HPLC and Lactobacillus casei microbiological assay of the cytosolic and mitochondrial fractions of pancreas, which contained 62 and 46%, respectively, of the total folate . In pancreas of control rats, cytosolic folates were 5-methyltetrahydrofolate (31% of total folates), tetrahydrofolate (54%) and 5- and 10-formyltetrahydrofolate (6 and 8%, respectively) . In the rats exposed to nitrous oxide, cytosolic 5-methyltetrahydrofolate concentrations were significantly greater (59% of total folates) and tetrahydrofolate concentrations were significantly lower (32%) than in controls; however, total cytosolic folate levels were unaffected by nitrous oxide exposure . In controls, mitochondrial folates were composed of 5-methyltetrahydrofolate (9% of total folates), tetrahydrofolate (60%) and 5- and 10-formyltetrahydrofolate (22 and 10%, respectively) . Exposure to nitrous oxide led to significantly lower total mitochondrial folates (1.49 +/- 0.18 vs . 0.75 +/- 0.29 nmol/g, control vs . nitrous oxide, P < 0.05) . This was due to a significantly lower concentration of tetrahydrofolate and 5-formyltetrahydrofolate, but not of 5-methyl- or 10-formyltetrahydrofolate . The activity of methionine synthase was 85% lower (P < 0.001) in pancreatic extracts of rats exposed to nitrous oxide than in controls . These results show that cytosolic folates accumulate in pancreas as the 5-methyl derivative at the expense of other reduced folates, as happens in liver . However, in contrast to results in liver, the mitochondrial folate concentration was lower in the pancreas of rats exposed to nitrous oxide, and this decline was limited to the 5-formyl- and tetrahydrofolate derivatives.

Lancet, 1997 Aug 23, 350(9077), 546 - 50
HIV-1 infection associated with abnormal vaginal flora morphology and bacterial vaginosis; Sewankambo N et al.; BACKGROUND: In-vitro research has suggested that bacterial vaginosis may increase the survival of HIV-1 in the genital tract . Therefore, we investigated the association of HIV-1 infection with vaginal flora abnormalities, including bacterial vaginosis and depletion of lactobacilli, after adjustment for sexual activity and the presence of other sexually transmitted diseases (STDs) . METHODS: During the initial survey round of our community-based trial of STD control for HIV-1 prevention in rural Rakai District, southwestern Uganda, we selected 4718 women aged 15-59 years . They provided interview information, blood for HIV-1 and syphilis serology, urine for detection of Chlamydia trachomatis and Neisseria gonorrhoeae, and two self-administered vaginal swabs for culture of Trichomonas vaginalis and gram-stain detection of vaginal flora, classified by standardised, quantitative, morphological scoring . Scores 0-3 were normal vaginal flora (predominant lactobacilli) . Higher scores suggested replacement of lactobacilli by gram-negative, anaerobic microorganisms (4-6 intermediate; 7-8 and 9-10 moderate and severe bacterial vaginosis) . FINDINGS: HIV-1 frequency was 14.2% among women with normal vaginal flora and 26.7% among those with severe bacterial vaginosis (p < 0.0001) . We found an association between bacterial vaginosis and increased HIV-1 infection among younger women, but not among women older than 40 years; the association could not be explained by differences in sexual activity or concurrent infection with other STDs . The frequency of bacterial vaginosis was similar among HIV-1-infected women with symptoms (55.0%) and without symptoms (55.7%) . The adjusted odds ratio of HIV-1 infection associated with any vaginal flora abnormality (scores 4-10) was 1.52 (95% CI 1.22-1.90), for moderate bacterial vaginosis (scores 7-8) it was 1.50 (1.18-1.89), and for severe bacterial vaginosis (scores 9-10) it was 2.08 (1.48-2.94) . INTERPRETATION: This cross-sectional study cannot show whether disturbed vaginal flora increases susceptibility to HIV-1 infection . Nevertheless, the increased frequency of HIV-1 associated with abnormal flora among younger women, for whom HIV-1 acquisition is likely to be recent, but not among older women, in whom HIV-1 is likely to have been acquired earlier, suggests that loss of lactobacilli or presence of bacterial vaginosis may increase susceptibility to HIV-1 acquisition . If this inference is correct, control of bacterial vaginosis could reduce HIV-1 transmissionPIP: A study of 4718 women 15-49 years old in southwestern Uganda's Rakai district suggests that the loss of lactobacilli and the presence of bacterial vaginosis may increase susceptibility to HIV-1 . These women were part of an ongoing community-based trial of sexually transmitted disease (STD) control as a strategy for AIDS prevention . The rate of HIV-1 infection among these women was 19.5% . Moderate bacterial vaginosis was detected in 44.5% of women, while 6.4% had severe bacterial vaginosis . STD rates were 10.2% for active or recent syphilis, 22.4% for trichomonas, 2.4% for gonorrhea, and 3.6% for chlamydia . The HIV rate was lowest (14.2%) among women with normal bacterial flora and highest (26.7%) among those with severe bacterial vaginosis . The HIV-abnormal flora association was higher in younger women, for whom HIV acquisition is likely to be recent, than in older women . In multiple logistic regression analyses adjusted for age, number of sexual partners, trichomonas, and syphilis, the odds ratio (OR) for HIV-1 infection associated with any abnormal vaginal flora was 1.52 (95% confidence interval {CI}, 1.22-1.90) and with all bacterial vaginosis was 1.56 (95% CI, 1.24-1.97) . These adjusted ORs were 1.50 (95% CI, 1.18-1.89) for moderate and 2.08 (95% CI, 1.48-2.94) for severe bacterial vaginosis . A cross-sectional study cannot ascertain whether the abnormalities in vaginal flora occurred before or after HIV seroconversion . However, the significantly increased proportion of HIV-infected women with depleted or absent vaginal lactobacilli is consistent with in vitro studies showing that hydrogen peroxidase-producing lactobacilli in vaginal flora inhibit HIV-1 viral replication . If the ongoing prospective study suggests a causal association with HIV, treatment of abnormal flora or bacterial vaginosis with inexpensive, effective drugs such as metronidazole may be indicated .

FEMS Microbiol Lett, 1997 Aug 15, 153(2), 455 - 63
Inhibition of in vitro growth of enteropathogens by new Lactobacillus isolates of human intestinal origin; Drago L et al.; Three human Lactobacillus strains, coded B21060, B21070 and B21190, have recently been isolated . The strains show a series of features (acid and bile resistance, adhesion to various types of mucosal cell) which make them particularly promising for the preparation of probiotic products . In the present study, the ability of the strains to inhibit the growth of pathogens in coculture was investigated . Lactobacilli were incubated simultaneously or after one overnight growth with enterotoxigenic Escherichia coli, Salmonella enteritidis or Vibrio cholerae . After 24 and 48 h, bacterial counts of the pathogens and of the lactobacilli were performed . The results showed that these Lactobacillus strains inhibited the in vitro growth of E . coli and S . enteritidis under both conditions . Moreover, a cumulative effect was observed for mixtures of lactobacilli . In contrast, no significant inhibition of Vibrio cholerae growth was observed, provided that the pH of the medium was kept constant . The presence of the pathogens did not affect the growth of the Lactobacillus strains . Moreover, each of the Lactobacillus strains showed coaggregation ability with two pathogenic E . coli strains, namely ATCC 25922 and ATCC 35401.

J Appl Microbiol, 1997 Aug, 83(2), 248 - 58
Detection of bacteriocins of lactic acid bacteria isolated from foods and comparison with pediocin and nisin; Coventry MJ et al.; A total of 663,533 colonies from 72 dairy and meat sources showed a detection rate of 0.2% for bacteriocin producers using direct plating techniques . A further 83,000 colonies from 40 fish and vegetable sources showed a detection rate of 3.4% for bacteriocin producers using selective enrichment procedures . A collection of seven purified isolates showing a different host spectrum of bacteriocin activity and with the ability to produce bacteriocins in broth culture were compared with nisin and pediocin (with respect to their inhibitory activity, determined by the critical dilution method), against various indicator bacteria in agar and broth . The sensitivity of Listeria species to various bacteriocins was influenced by the agar and broth test systems used . A Lactobacillus curvatus strain was found to be the most suitable indicator for quantitating antimicrobial effects of all the bacteriocins investigated in both agar and broth test systems . The bacteriocin-producing isolates were characterized by biochemical reactions and DNA restriction enzyme profiles and taxonomic identification revealed species of Lactobacillus, Carnobacterium and Lactococcus assigned on the basis of 16S rDNA sequences.

J Appl Microbiol, 1997 Aug, 83(2), 219 - 26
Identification of sites of injury in Lactobacillus bulgaricus during heat stress; Teixeira P et al.; Heat resistance of Lactobacillus bulgaricus in skimmed milk at 62 degrees, 64 degrees, 65 degrees and 66 degrees C was studied . The response to increasing temperatures in this range was not linear, with temperatures at 65 degrees C and above giving a lower survival rate than would be predicted from experiments at lower temperatures . To identify sites of injury at these temperatures, chemical markers were used . Heating at 64 degrees C and below resulted in damage to the cytoplasmic membrane . At temperatures of 65 degrees C and above chemical markers also indicated damage in the cell wall and proteins . Using differential scanning calorimetry analysis of whole cells of Lact . bulgaricus seven main peaks were observed (1-51, m1-61, m2-73, n-80, p-89, q-100, r-112 degrees C) . Three of these peaks (l(r), m(r) and p(r)) were the result of reversible reactions . Analysis of cell fractions identified the cell structure involved in giving rise to each of the three reversible peaks; l(r), cell membrane lipids, m(r), ribosomes, and p(r), DNA . The evidence presented in this paper shows that irreversible reactions in the cell ribosomes are a critical site of damage in Lact . bulgaricus during heat stress in liquid media at 65 degrees C and above.

J Dairy Sci, 1997 Aug, 80(8), 1537 - 45
Improvement of lactose digestion by humans following ingestion of unfermented acidophilus milk: influence of bile sensitivity, lactose transport, and acid tolerance of Lactobacillus acidophilus; Mustapha A et al.; The influence of bile sensitivity, lactose transport, and acid tolerance of Lactobacillus acidophilus on in vivo digestion of lactose was investigated . Four strains of L . acidophilus exhibiting varied degrees of lactose transport, beta-galactosidase activity, and bile sensitivity were used to prepare unfermented acidophilus milks . Lactose malabsorption was evaluated by measuring breath H2 excretion off 11 lactose maldigesting subjects following ingestion of four acidophilus test milks . Test meals were fed in a randomized double-blind protocol . Consumption of acidophilus milk (2% fat) containing strains B, N1, and E significantly reduced mean total H2 production compared with that of the control reduced-fat (2% fat) milk, but milk containing strain ATCC 4356 did not differ from the control . Acidophilus milk containing L . acidophilus N1 was the most effective of the four acidophilus milks in improving lactose digestion and tolerance . Strain N1 exhibited the lowest beta-galactosidase activity and lactose transport but the greatest bile and acid tolerance of the four strains . The results indicated that bile and acid tolerance may be important factors to consider when L . acidophilus strains are selected for improving lactose digestion and tolerance.

J Dairy Sci, 1997 Aug, 80(8), 1497 - 504
Purification and characterization of a dipeptidase from Lactobacillus casei ssp . casei IFPL 731 isolated from goat cheese made from raw milk; Fernandez-Espla MD et al.; A dipeptidase was purified to homogeneity from the cell-free extract of Lactobacillus casei ssp . casei IFPL 731 by a combination of heat treatment, hydrophobic interaction chromatography, anion-exchange chromatography, and gel filtration . A purification factor of 395-fold was obtained, and yield was 20% . The dipeptidase was shown to be a metal-dependent enzyme; optimal activity was at pH 7.5 and 60 to 75 degrees C, and the enzyme had a high degree of thermal stability . Molecular mass was estimated by SDS-PAGE and gel filtration to be 46 kDa, which suggested that the enzyme existed as a monomer . Enzyme activity was most effectively inhibited by metal-chelating agents, reducing agents, or sulfhydryl group reagents . After inhibition with phenanthroline, activity was partially restored by Co2+ and Mn2+ . The kinetics of Phe-Ala and Leu-Leu did not follow Michaelis-Menten saturation kinetics but exhibited a mixture of positive and negative cooperativity for the successive binding of molecules of the same substrate.

Microbiology, 1997 Aug, 143 ( Pt 8), 2733 - 41
Efficient secretion of the model antigen M6-gp41E in Lactobacillus plantarum NCIMB 8826; Hols P et al.; Four Lactobacillus strains (Lb . plantarum NCIMB 8826, Lb . paracasei LbTGS1.4, Lb . casei ATCC 393 and Lb . fermentum KLD) were tested for their ability to produce and secrete heterologous proteins . These strains were first screened with an alpha-amylase reporter under the control of a set of expression or expression/secretion signals from various lactic acid bacteria . With most of the constructions tested, the level of extracellular production was highest in Lb . plantarum NCIMB 8826, and lowest in Lb . paracasei LbTGS1.4 . These two strains were next assayed using a model antigen consisting of the N-terminal part of the M6 protein from Streptococcus pyogenes fused to the linear epitope ELDKWAS from human immunodeficiency virus gp41 protein . Secretion of this heterologous protein was inefficient in Lb . paracasei LbTGS1.4, which accumulated a large intracellular pool of the unprocessed precursor, whereas Lb . plantarum NCIMB 8826 was able to secrete the antigen to a level as high as 10 mg l-1.

FEMS Microbiol Lett, 1997 Aug 1, 153(1), 191 - 7
Identification and phylogenetic analysis of Lactobacillus using multiplex RAPD-PCR; Daud Khaled AK et al.; Multiplex RAPD-PCR was used to generate unique and identifying DNA profiles for isolates of the genus Lactobacillus . The method that was used was based on the combination of two 10-mer oligonucleotides in a single PCR . The generated RAPD profiles enabled discrimination of all lactobacillus strains that were used in this study . A dendrogram was generated from the RAPD profiles . The results of genetic relatedness obtained from the dendrogram were compared with the results obtained using carbohydrate fermentation profiles . Most of the gastrointestinal isolates studied could not be grouped using carbohydrate fermentation profiles . The RAPD profiles provided sufficient information to prepare a dendrogram of genetic relatedness . The gastrointestinal isolates were clustered together on the dendrogram . Furthermore an isolate originating from the stomach (strain ML004) was closely related to Lactobacillus fermentum . It was concluded that multiplex RAPD-PCR was useful for characterisation and inference of relatedness of Lactobacillus isolates.

Appl Environ Microbiol, 1997 Aug, 63(8), 3336 - 40
Cloning and expression of an endo-1,3-1,4-beta-glucanase gene from Bacillus macerans in Lactobacillus reuteri; Heng NC et al.; Strains of the gastrointestinal species Lactobacillus reuteri were electrotransformed with plasmid constructs containing the endo-1,3-1,4-beta-glucanase gene (bglM) of Bacillus macerans . The enzyme was expressed and secreted by the lactobacilli . A plasmid construct containing the bglM gene lacking its promoter was derived and was demonstrated to be useful as a promoter probe vector.

J Clin Invest, 1997 Aug 1, 100(3), 658 - 63
Genetic bias in immune responses to a cassette shared by different microorganisms in patients with rheumatoid arthritis; La Cava A et al.; Rheumatoid arthritis (RA) is an autoimmune disease associated with HLA-DRbeta1 alleles which contain the QKRAA amino acid sequence in their third hypervariable region(s) . The QKRAA sequence is also expressed by several human pathogens . We have shown previously that an Escherichia coli peptide encompassing QKRAA is a target of immune responses in RA patients . Here we address two questions: first, whether QKRAA may function as an "immunological cassette" with similar, RA-associated, immunogenic properties when expressed by other common human pathogens; and second, what is the influence of genetic background in the generation of these responses . We find that early RA patients have enhanced humoral and cellular immune responses to Epstein-Barr virus and Brucella ovis and Lactobacillus lactis antigens which contain the QKRAA sequence . These results suggest that the QKRAA sequence is an antigenic epitope on several different microbial proteins, and that RA patients recognize the immunological cassette on different backgrounds . ANOVA of immune responses to "shared epitope" antigens in monozygotic twin couples shows that, despite significantly elevated responses in affected individuals, a similarity between pairs is retained, thus suggesting a role played either by hereditary or shared environmental factors in the genesis or maintenance of these responses.

J Nutr, 1997 Aug, 127(8), 1489 - 95
In vitro lactose fermentation by human colonic bacteria is modified by Lactobacillus acidophilus supplementation; Jiang T et al.; Adaptation of the colonic flora to lactose may contribute to lactose digestion in lactose maldigesters, and supplementation with Lactobacillus acidophilus may modify colonic fermentation of lactose and short-chain fatty acid production . We evaluated the capability of colonic bacteria to ferment lactose and the ability of L . acidophilus to modify lactose fermentation by the colonic microflora in vitro . An anaerobic continuous culture was established and inoculated with fresh samples of human feces . Lactose infusion was maintained at 25 g/d and pH at 6.7 . L . acidophilus strain LA-1 (1.5 x 10(10) cells) was introduced into the fermenter on d 0 or added daily on d 0 through 4 . The control was the continuous culture without the addition of lactobacilli . Rapid adaptation of colonic bacteria to lactose occurred within 1-2 d, with a significant decrease in lactose concentration and increase in beta-galactosidase activity, and lactose concentrations fell below 3 mmol/L by d 7 . Supplementation with strain LA-1 resulted in a significantly greater decrease in lactose concentration and greater increase in acetate and propionate production within the first day compared with the control group . However, there was no significant difference between the fermentation treated with L . acidophilus daily and the control after the first day . These data suggest that the colonic bacteria adapt quickly to lactose, causing efficient utilization of lactose . L . acidophilus supplementation may enhance lactose fermentation during early periods when the adaptation is not established in this model.

J Biotechnol, 1997 Jul 23, 56(1), 25 - 31
Lactic acid production in a cell retention continuous culture using lignocellulosic hydrolysate as a substrate; Melzoch K et al.; The effect of lignocellulosic hydrolysate of crushed corn cobs on the kinetics of growth and lactic acid production of Lactobacillus casei and L . lactis in the cell retention continuous culture was studied . The continuous cultivations were carried out in a continuous flow stirred bioreactor combined in a recycle loop with an ultrafiltration module retaining all biomass and allowing the continuous removal of metabolites, including lactic acid, as a cell-free permeate . Based on computer-aided analysis of experimental data, a simple physiological model of lactic acid cultivation was developed . The parameters of the model were estimated by non-linear regression.

J Ind Microbiol Biotechnol, 1997 Jul, 19(1), 28 - 33
Detection and partial characterization of a bacteriocin produced by Carnobacterium piscicola 213; Khouiti Z et al.; BLIS 213, is a bacteriocin-like inhibitory substance produced by Carnobacterium piscicola 213 . It is active against Carnobacterium, Enterococcus and Listeria spp . No activity was observed against tested Lactobacillus, Lactococcus, Leuconostoc and Pediococcus strains, nor against Gram-negative bacteria . The BLIS 213 activity was inactivated by several proteolytic enzymes . It was heat resistant (121 degrees C for 20 min), and stable over a pH range of 2-8 . Activity was determined by a dilution micromethod; it was increased after SDS treatment . A mutant strain which lacks bacteriocin production was isolated and designated as Carnobacterium piscicola 213a . It had the same phenotypic and biochemical properties as the parent strain, and was not sensitive to bacteriocin activity . The apparent molecular weight of the bacteriocin in the crude extract was greater than 10 kDa . It was about 6 kDa after SDS-PAGE of a partially purified bacteriocin by adsorption on producer cells . The isoelectric point of the BLIS 213 was around 9.3.

Gut, 1997 Jul, 41(1), 49 - 55
Prevention of Helicobacter pylori infection by lactobacilli in a gnotobiotic murine model; Kabir AM et al.; BACKGROUND: Helicobacter pylori is a bacterium which causes gastric inflammatory diseases . Oral inoculation of H pylori usually results in only a temporary colonisation without a successful infection in the stomach of conventional mice in which lactobacilli are the predominant indigenous bacteria . AIM: To determine whether lactobacilli exert an inhibitory effect on colonisation by H pylori in the stomach . METHODS: The effects of H pylori on attachment to murine and human gastric epithelial cells and the H pylori mediated release of interleukin-8 (IL-8) by these cells were examined in vitro . Lactobacillus salivarius infected gnotobiotic BALB/c mice and control germ free mice were inoculated orally with H pylori to examine whether L salivarius can inhibit colonisation by H pylori . RESULTS: L salivarius inhibited both the attachment and IL-8 release in vitro . H pylori could not colonise the stomach of L salivarius infected gnotobiotic BALB/c mice, but colonised in large numbers and subsequently caused active gastritis in germ free mice . In addition, L salivarius given after H pylori implantation could eliminate colonisation by H pylori . CONCLUSION: These findings suggest the possibility of lactobacilli being used as probiotic agents against H pylori.

Eur J Clin Microbiol Infect Dis, 1997 Jul, 16(7), 517 - 22
Relationship between hydrogen peroxide-producing strains of lactobacilli and vaginosis-associated bacterial species in pregnant women; Rosenstein IJ et al.; This study was conducted to determine the relationship between lactobacilli and bacterial species associated with bacterial vaginosis in pregnancy and the prevalence of H2O2-producing and non-producing strains of lactobacilli in pregnant women whose vaginal flora had already been analysed . Information was available for 174 pregnant women whose vaginal flora had been evaluated previously by examining gram-stained vaginal smears: 50 had grade III flora (bacterial vaginosis) . 50 grade II flora, 41 flora graded as abnormal which then reverted to grade I (revertants) and 33 normal flora (controls) . Lactobacilli were isolated from 19 of 50 women whose vaginal flora was grossly abnormal culturally and categorised as grade III by Gram staining . In 6 of these 50 women lactobacilli were isolated in large numbers, i.e . 10(5)-10(6) cfu/ml . H2O2-producing strains of lactobacilli were isolated from 11 of 12 women with grade III flora who were randomly selected from this group . Thus, in those 11 women it appears that H2O2-producing lactobacilli had not protected them from developing bacterial vaginosis . Bacterial species associated with vaginosis were isolated in high numbers from a large proportion of women in the revertant and grade II groups in association with high counts of lactobacilli . Thus, in some women it is possible that a change to an abnormal flora could occur before the complete disappearance of lactobacilli . It is concluded that bacterial vaginosis may develop in some women despite the presence of H2O2-producing strains of lactobacilli and that other factors, as yet unidentified, might be conducive to the appearance of abnormal bacterial flora with progression to vaginosis.

Biosci Biotechnol Biochem, 1997 Jul, 61(7), 1168 - 71
Purification and characterization of glutamate decarboxylase from Lactobacillus brevis IFO 12005; Ueno Y et al.; Glutamate decarboxylase (GAD) {EC 4.1.1.15} was purified from a cell-free extract of Lactobacillus brevis IFO 12005 by chromatographies on Sephadex G-100, DEAE-Sepharose CL-6B, and Mono Q . About 9 mg of purified GAD was obtained from 90.2 g of wet cells . The purified preparation showed a single protein band on SDS-PAGE . The molecular weights of purified GAD by SDS-PAGE and gel filtration on Superdex 200 were 60,000 and 120,000, respectively, indicating that GAD from L . brevis exists as a dimer . The N-terminal amino acid sequence of the purified GAD was NH2-Met-Asn-Lys-Asn-Asp-Gln-Glu-Gln-Thr- . The optimum pH and temperature of GAD were at pH 4.2 and at 30 degrees C . The GAD activity was increased by the addition of sulfate ions in a dose-dependent manner . The order of effects was as follows: ammonium sulfate > sodium sulfate > magnesium sulfate, indicating that the increase of hydrophobic interaction between subunits causes the increase of GAD activity . The purified GAD reacted only with L-glutamic acid as a substrate and the K(m), kcat, and kcat/K(m) values were 9.3 mM, 6.5 S-1, and 7 x 10(2) M-1 S-1, respectively.

Acta Obstet Gynecol Scand, 1997 Jul, 76(6), 521 - 7
Fetal fibronectin and microorganisms in vaginal fluid of women with complicated pregnancies; Goffeng AR et al.; OBJECTIVES: To determine vaginal fetal fibronectin in women with pregnancies complicated by preterm labor (PTL), preterm premature rupture of the membranes (PPROM) or bleeding; to investigate possible relationships to the vaginal microflora; and to assess the ability to predict preterm delivery from these measures . MATERIAL AND METHODS: Group comparative study between women of the same gestational age with a normal pregnancy (n = 28) and consecutive women admitted with PTL (n = 63), PPROM (n = 18) and bleeding (n = 21) . Samples of vaginal fluid were collected at the time of admission in complicated pregnancies and from the women with normal pregnancies . Fetal fibronectin was determined by enzyme immunoassay and quantitative aerobic and anaerobic microbiological cultures were performed . RESULTS: The number of positive (> or = 0.05 mg/L) vaginal fetal fibronectin values was higher among women with PTL, PPROM and bleeding compared to controls (p < 0.001) . A positive fibronectin value was predictive of delivery < or = 34 weeks (sensitivity 64%, specificity 87%) . The absence of hydrogen peroxide-producing lactobacilli was predictive for preterm delivery < 34 weeks (sensitivity of 100%, specificity 35%) . CONCLUSIONS: The presence of vaginal fibronectin and the absence of hydrogen peroxide-producing lactobacilli was indicative of an increased risk for preterm delivery < 34 weeks.

J Appl Microbiol, 1997 Jul, 83(1), 111 - 9
Antimicrobial activity of food-related Penicillium sp . against pathogenic bacteria in laboratory media and a cheese model system; Larsen AG et al.; Food-related Penicillium species (n = 34) and Geotrichum candidum (n = 11) grown on Czapek Dox and brie agar were tested for their ability to suppress growth of pathogenic bacteria . Ten out of 13 P . camemberti showed antagonistic activity while the other species did not interact significantly with the bacterial growth . The order of inhibition was: Gram-negative bacteria and Bacillus cereus > Listeria monocytogenes, Lactococcus sp . > Micrococcus sp . whereas Lactobacillus sp., Staphylococcus aureus and some Micrococcus sp . were unaffected . When Salmonella typhimurium was inoculated together with P . camemberti P25 in brie agar, bacterial growth was inhibited during the first 6 d of incubation whereafter growth started . The inhibition of L . monocytogenes was similar but less pronounced . The antimicrobial activity produced by P . camemberti P25 and L84 was enhanced with increasing amount of sucrose in the medium . The activity was increased at low pH and destroyed at pH above 8 . It was detectable at 15 degrees C but not at 37 degrees C indicating that volatile metabolites might be involved . No significant accumulation of organic acids and no secondary metabolites such as mycotoxins were detected . HSGC-MS analysis indicated that acetaldehyde, benzaldehyde, 3-methylbutanal and 1-octen-3-ol were produced by P . camemberti during the period when inhibitory activity was observed . Pure acetaldehyde and benzaldehyde were shown to be inhibitory to L . monocytogenes and Salm . typhimurium when grown at 15 degrees C and pH 5.5 and 7.0.

Appl Environ Microbiol, 1997 Jul, 63(7), 2850 - 6
Molecular genetic characterization of the L-lactate dehydrogenase gene (ldhL) of Lactobacillus helveticus and biochemical characterization of the enzyme; Savijoki K et al.; The Lactobacillus helveticus L-(+)-lactate dehydrogenase (L-LDH) gene (ldhL) was isolated from a lambda library . The nucleotide sequence of the ldhL gene was determined and shown to have the capacity to encode a protein of 323 amino acids (35.3 kDa) . The deduced sequence of the 35-kDa protein revealed a relatively high degree of identity with other lactobacillar L-LDHs . The highest identity (80.2%) was observed with the Lactobacillus casei L-LDH . The sizes and 5' end analyses of ldhL transcripts showed that the ldhL gene is a monocistronic transcriptional unit . The expression of ldhL, studied as a function of growth, revealed a high expression level at the logarithmic phase of growth . The ldhL gene is preceded by two putative -10 regions, but no corresponding -35 regions could be identified . By primer extension analysis, the ldhL transcripts were confirmed to be derived from the -10 region closest to the initiation codon . However, upstream of these regions additional putative -10/-35 regions could be found . The L-LDH was overexpressed in Escherichia coli and purified to homogeneity by two chromatographic steps . The purified L-LDH was shown to be a nonaliosteric enzyme, and amino acid residues involved in allosteric regulation were not conserved in L . helveticus L-LDH . However, a slight enhancement of enzyme activity was observed in the presence of fructose 1,6-diphosphate, particularly at neutral pH . A detailed enzymatic characterization of L-LDH was performed . The optimal reaction velocity was at pH 5.0, where the kinetic parameters K(m), and Kcat for pyruvate were 0.25 mM and 643 S-1, respectively.

Biochemistry, 1997 Jul 1, 36(26), 8071 - 81
2-Oxo-3-alkynoic acids, universal mechanism-based inactivators of thiamin diphosphate-dependent decarboxylases: synthesis and evidence for potent inactivation of the pyruvate dehydrogenase multienzyme complex; Brown A et al.; A new class of compounds, the 2-oxo-3-alkynoic acids with a phenyl substituent at carbon 4 was reported by the authors as potent irreversible and mechanism-based inhibitors of the thiamin diphosphate- (ThDP-) dependent enzyme pyruvate decarboxylase {Chiu, C.-F., & Jordan, F . (1994) J . Org . Chem . 59, 5763-5766} . The method has been successfully extended to the synthesis of the 4-, 5-, and 7-carbon aliphatic members of this family of compounds . These three compounds were then tested on three ThDP-dependent pyruvate decarboxylases: the Escherichia coli pyruvate dehydrogenase multienzyme complex (PDHc) and its E1 (ThDP-dependent) component, pyruvate oxidase (POX, phosphorylating; from Lactobacillus plantarum),and pyruvate decarboxylase (PDC) from Saccharomycescerevisiae . All three enzymes were irreversibly inhibited by the new compounds . The 4-carbon acid is the best substrate-analog inactivator known to date for PDHc, more potent than either fluoropyruvate or bromopyruvate . The following conclusions were drawn from extensive studies with PDHc: (a) The kinetics of inactivation of PDH complexes and of resolved E1 by 2-oxo-3-alkynoic acids is time- and concentration-dependent . (b) The 4-carbon acid has a Ki 2 orders of magnitude stronger than the 5-carbon acid, clearly demonstrating the substrate specificity of PDHc . (c) The rate of inactivation of PDH complexes and of resolved E1 by 2-oxo-3-alkynoic acids is enhanced by the addition of ThDP and MgCl2 . (d) Pyruvate completely protects E1 and partially protects PDHc from inactivation by 2-oxo-3-butynoic acid . (e) E1 but not E2-E3 is the target of inactivation by 2-oxo-3-butynoic acid . (f) Inactivation of E1 by 2-oxo-3-butynoic acid is accompanied by modification of 1.3 cysteines/E1 monomer . The order of reactivity with the 4-carbon acid was PDHc > POX > PDC . While the order of reactivity with PDHc and POX was 2-oxo-3-butynoic acid > 2-oxo-3-pentynoic acid > 2-oxo-3-heptynoic acid, the order of reactivity was reversed with PDC.

Int J Food Microbiol, 1997 Jun 17, 37(1), 83 - 6
Lactobacillus rhamnosus GG (ATCC 53103) and platelet aggregation in vitro; Korpela R et al.; Lactobacillus rhamnosus GG is an experimentally and clinically well documented probiotic used in different dairy products . The present study aimed to investigate the safety aspects of Lactobacillus rhamnosus GG, particularly with respect to platelet aggregation, the initiating event in thrombosis . Platelet rich plasma was separated from the blood of healthy volunteers, and the effects of Lactobacillus rhamnosus GG (ATCC 53103), Lactobacillus rhamnosus (ATCC 7469) and Enterococcus faecium T2L6 in different dilutions on spontaneous, ADP- and adrenaline-induced aggregation were tested . The bacteria did not influence spontaneous aggregation . Only Enterococcus faecium T2L6 enhanced the adrenaline-induced aggregation, with a less clear effect on ADP-induced aggregation.

FEBS Lett, 1997 Jun 16, 409(3), 385 - 90
Thermodynamic characterization of the binding of dCMP to the Asn229Asp mutant of thymidylate synthase; Tellez-Sanz R et al.; Isothermal titration microcalorimetry and equilibrium dialysis have been used to characterize the binding of 2'-deoxycytidine 5'-monophosphate (dCMP) to the Asn229Asp mutant of Lactobacillus casei recombinant thymidylate synthase at pH 7.4 over a temperature range of 15 degrees C to 35 degrees C . Equilibrium dialysis analysis shows that dCMP binds to two sites in the dimer of both wild-type and mutant thymidylate synthase . A concomitant net uptake of protons with binding of dCMP to both enzymes, was detected carrying out calorimetric experiments in various buffer systems with different heats of ionization . The change in protonation for binding of dCMP to wild-type enzyme is lower than that obtained for binding of this nucleotide to TS N229D, which suggests that the pK value of Asp-229 is increased upon dCMP binding to the mutant enzyme . At 25 degrees C, although the binding of dCMP to wild-type and N229D TS is favoured by both enthalpy and entropy changes, the enthalpy change is more negative for the mutant protein . Thus, the substitution of Asn 229 for Asp results in a higher affinity of TS for dCMP due to a more favourable enthalpic contribution . The Gibbs energy change of binding of dCMP to the mutant enzyme is weakly temperature-dependent, because of the enthalpy-entropy compensation arising from a negative heat capacity change of binding equal to -0.83 +/- 0.02 kJ K(-1) per mol of dCMP bound.

FEMS Microbiol Lett, 1997 Jun 15, 151(2), 169 - 76
Purification and partial characterization of an antigen specific to Lactobacillus brevis strains with beer spoilage activity; Yasui T et al.; Certain Lactobacillus brevis strains are resistant to hop-derived compounds such as isohumulone and are able to grow in beer . In this study, we raised an antiserum against our beer spoilage laboratory strain L . brevis 578 which reacted with 23 of 24 beer spoilers and two of 13 non-spoilers in precipitation reactions using 0.5 M NaOH cell extracts . This specific antigen to the beer spoilage L . brevis strains (SABSL) was demonstrated to be located beneath the S-layer proteins by agglutination reactions using S-layer protein-stripped cells obtained by treatment with 0.1 M NaOH . SABSL was purified using an affinity column coupled with an antibody against SABSL . The purified antigen was hydrolyzed with 2 M HCl and the hydrolyzate was analyzed by thin-layer chromatography and enzymatic analysis . The results showed that SABSL contains glycerol, phosphate, glycerophosphate, D-galactose and D-glucose . D-Galactose and D-glucose accounted for 4.7% and 0.1% of the composition, respectively . Melibiose, but not mannose, inhibited the precipitation reaction . Intense precipitation reactions were obtained with fractions which did not bind to the ConA-column . These results indicate that the immunodominant component of the SABSL is galactose and the SABSL determinant is most probably a galactosylated glycerol teichoic acid . The antiserum raised against the beer spoilage strain L . brevis 578 could distinguish between Pediococcus beer spoilers and non-spoilers in precipitation reactions.

J Radiat Res (Tokyo), 1997 Jun, 38(2), 111 - 20
Acceleration of granulocytic cell recovery in irradiated mice by a single subcutaneous injection of a heat-killed Lactobacillus casei preparation; Furuse M et al.; Flow cytometric analysis showed that the treatment of irradiated mice with a heat-killed Lactobacillus casei preparation (LC 9018) accelerated the recovery of granulocytic cell populations in peripheral blood, spleen and femur bone marrow . The recovery of the lymphocytic cell population was not accelerated while the recovery of the B-lymphocytic cell population was inhibited . Histological analysis also showed that the LC-9018 treatment markedly enhanced granulopoiesis in the spleen and bone marrow of irradiated mice . The same LC-9018 treatment significantly increased 30-day survival rates of athymic nude mice after lethal whole-body irradiation . The recovery of the granulocytic cell population in peripheral blood of irradiated athymic nude mice was also accelerated by LC-9018 treatment . Our results suggest that LC 9018 protected lethally irradiated mice from bone marrow death by enhancing granulopoiesis rather than lymphopoiesis and that the contribution of activated T lymphocytes to the enhancement of the granulopoiesis was small.

Endocr J, 1997 Jun, 44(3), 357 - 65
Antidiabetic effects of an oral administration of Lactobacillus casei in a non-insulin-dependent diabetes mellitus (NIDDM) model using KK-Ay mice; Matsuzaki T et al.; The antidiabetic effects of Lactobacillus casei (LC) on a non-insulin-dependent diabetes mellitus (NIDDM) model, KK-Ay mice, were investigated . The oral administration of LC to male 4-week-old KK-Ay mice, or raising the mice on a 0.05% LC-containing diet significantly decreased the plasma glucose at 8 to 10 weeks of age compared with the control group . The body weights of the LC-treated groups were lower than those of the control group, although the food intake was nearly the same in all groups . Phenotypic analysis of spleen cell surface markers revealed that the increase in CD4+ T cells at 12 weeks was significantly inhibited by the oral treatment with LC . Cytokine production, especially that of interferon-gamma and interleukin 2, was also inhibited in the oral LC-treated group . The plasma insulin levels of the LC-treated groups were also lower than those of the control group, and the insulin binding potential of red blood cells in the LC-treated mice was augmented more than that in the control group . Taken together, these findings led us to conclude that the oral administration of LC in the NIDDM model mice, KK-Ay, was involved in the decrease in the plasma glucose level and modified the host immune responses.

J Nutr Sci Vitaminol (Tokyo), 1997 Jun, 43(3), 419 - 24
Stimulatory effect of phytin on acid production by Lactobacillus casei; Nakashima A; The stimulatory effect of phytin added to skim milk on acid production of Lactobacillus casei was examined . Phytin stimulated acid production of L . casei fairly well . The stimulatory effect of phytin on acid production was not shown when phytin was treated with Dowex 50 (H+) and neutralized by NaOH solution . The incinerated product of phytin maintained almost equal stimulatory effect on acid production as that before processing . The addition of Mn2+ in the amount contained in a reagent phytin augmented the stimulatory effect on acid production markedly . The further addition of Fe3+, Ca2+, Mg2+ and PO4(3-) in amounts corresponding to their contents in the preparation of phytin as well as Mn2+ increased the effect slightly . The four preparations of phytin contained 0.045-0.20% of Mn, and the greater the Mn content was, the greater the potentiation of acid production.

Microbiologia, 1997 Jun, 13(2), 201 - 8
Characterization and selection of lactobacilli isolated from Spanish fermented sausages; Rovira A et al.; The use of starter cultures to control and run the fermentative process is a usual way of manufacturing sausages in meat industries . The first stage in the starter culture designing process is to characterize the lactic acid bacteria isolated from these meat products, in order to select the best strains . The strains used for this study were isolated from different dry fermented sausages, obtained during the manufacturing process . The main tests used to identify the isolated bacteria were: microscopic-morphologic characteristics, catalase activity, production of gas, growth at 8, 15 and 45 degrees C, fermentation of carbohydrates and production of lactic acid isomers . A total of 194 strains were identified . Lactobacillus sake and Lactobacillus plantarum were the most frequent species . Other microbiological tests were also performed, and three strains of Lactobacillus sake were found which did not produce dextran from sucrose.

Community Dent Health, 1997 Jun, 14(2), 97 - 101
Multifactorial modelling for caries prediction in Jordanian university students; Sayegh A et al.; OBJECTIVE: To construct a prediction model for caries experience in Jordanian university students using a number of explanatory risk factors as predictors . DESIGN: Data on salivary flow rate, buffering capacity, streptococci and lactobacilli counts, plaque accumulation, oral hygiene and between meal sugar intakes were tested as predictors of clinically and radiographically registered DMFS: Methods of analysis included correlation, then multiple regression, and finally dichotomisation of the DMFS data and application of discriminant analysis and logistic regression . The latter analyses were conducted in order to predict in which caries risk group an individual belonged rather than predicting (as with regression) their actual caries status . Two dichotomisation schemes were investigated; dichotomisation at the mean and at the 75th percentile . SETTING: The University of Jordan . PARTICIPANTS: A random sample of 180 university students (77 male and 103 female) . OUTCOME MEASURES: Relationships were expressed as correlation coefficients, R2, and sensitivity, specificity and predictive values of the predictors, and also their validity and efficiency . RESULTS: The highest correlation coefficient achieved was 0.43 (P < 0.0001) between sugar-containing snack intakes and DMFS . The predicted power of the fitted multiple regression model was low R2 = 0.38) . Logistic regression with the DMFS data dichotomised at the 75th percentile indicated that the fitted caries model correctly identified 76 per cent of the subjects . Sensitivity and specificity values of the predictive battery were 80 per cent and 75 per cent respectively . CONCLUSIONS: The multifactorial aetiology of caries remains unclear and requires further research . In the meantime, well-documented preventive measures should be implemented for this and similar populations.

FEMS Immunol Med Microbiol, 1997 Jun, 18(2), 125 - 32
Inhibition of Salmonella typhimurium adhesion to Caco-2 cell cultures by Lactobacillus strain GG spent culture supernate: only a pH effect?
Lehto EM, Salminen SJ.
The effect of Lactobacillus GG and its spent culture supernate on the adhesion of Salmonella typhimurium to Caco-2 cells was investigated . Lactobacillus GG cells which had adhered to Caco-2 monolayers prior to the addition of S . typhimurium did not inhibit the adhesion . Adhesion of S . typhimurium was reduced in the presence of spent culture supernate from MRS broth cultures (spent culture supernate I) . Similar inhibition was observed with acidified fresh MRS . The viability experiments with Caco-2 cells indicated that the inhibition was presumably due to the death of cells under acidic conditions . Adhesion of S . typhimurium was reduced by pre-treating the bacteria with spent culture supernate I or with acidified MRS and whey broth prior to adhesion to Caco-2 monolayers . Pre-treatment with spent culture supernate II (from whey broth cultures) did not influence the adhesion . No inhibition was detected at neutral pH values . Therefore, the observed inhibition of S . typhimurium adhesion to Caco-2 monolayers with spent culture supernate I was most likely a pH effect.

J Appl Microbiol, 1997 Jun, 82(6), 783 - 90
DNA probe and PCR-specific reaction for Lactobacillus plantarum; Quere F et al.; A 300 bp DNA fragment of Lactobacillus plantarum isolated by randomly amplified polymorphic DNA (RAPD) analysis was cloned and sequenced . This fragment was tested using a dot-blot DNA hybridization to technique for its ability to identify Lact . plantarum strains . This probe hybridized with all Lact . plantarum strains tested and with some strains of Lact . pentosus, albeit more weakly . Two internal primers of this probe were selected (LbP11 and LbP12) and polymerase chain reaction (PCR) was carried out . All Lact . plantarum strains tested amplified a 250 bp fragment contrary to the other LAB species tested . This specific PCR for Lact . plantarum was also performed from colonies grown on MRS medium with similar results . These methods enabled the rapid and specific detection and identification of Lact . plantarum.

Appl Environ Microbiol, 1997 Jun, 63(6), 2213 - 7
Cloning and functional expression in Escherichia coli of the gene encoding the di- and tripeptide transport protein of Lactobacillus helveticus; Nakajima H et al.; The gene encoding the di- and tripeptide transport protein (DtpT) of Lactobacillus helveticus (DtpTLH) was cloned with the aid of the inverse PCR technique and used to complement the dipeptide transport-deficient and proline-auxotrophic Escherichia coli E1772 . Functional expression of the peptide transporter was shown by the uptake of prolyl-{14C} alanine in whole cells and membrane vesicles . Peptide transport via DtpT in membrane vesicles is driven by the proton motive force . The system has specificity for di- and tripeptides but not for amino acids or tetrapeptides . The dtpTLH gene consists of 1,491 bp, which translates into a 497-amino-acid polypeptide . DtpTLH shows 34% identity to the di- and tripeptide transport protein of Lactococcus lactis and is also homologous to various peptide transporters of eukaryotic origin, but the similarity between these proteins is confined mainly to the N-terminal halves.

Appl Environ Microbiol, 1997 Jun, 63(6), 2117 - 23
Single-crossover integration in the Lactobacillus sake chromosome and insertional inactivation of the ptsI and lacL genes; Leloup L et al.; Single-crossover homologous integration in Lactobacillus sake was studied . Integration was conducted with nonreplicative delivery vector pRV300 . This vector is composed of a pBluescript SK- replicon for propagation in Escherichia coli and an erythromycin resistance marker . Random chromosomal DNA fragments of L . sake 23K ranging between 0.3 and 3.4 kb were inserted into pRV300 . The resulting plasmids were able to integrate into the chromosome by homologous recombination as single copies and were maintained stably . The single cross-over integration frequency was logarithmically proportional to the extent of homology between 0.3 and 1.2 kb and reached a maximum value of 1.4 x 10(3) integrants/micrograms of DNA . We used this integration strategy to inactivate the ptsI gene, encoding enzyme I of the phosphoenolpyruvate:carbohydrate phosphotransferase system, and the lacL gene, which is one of the two genes required for the synthesis of a functional beta-galactosidase . The results indicated that our method facilitates genetic analysis of L . sake.

Appl Environ Microbiol, 1997 Jun, 63(6), 2111 - 6
Molecular cloning and analysis of the ptsHI operon in Lactobacillus sake; Stentz R et al.; The ptsH and ptsI genes of Lactobacillus sake, encoding the general enzymes of the phosphoenolpyruvate: carbohydrate phosphotransferase system (PTS), were cloned and sequenced . HPr (88 amino acids), encoded by ptsH, and enzyme I (574 amino acids), encoded by ptsI, are homologous to the corresponding known enzymes of other bacteria . Nucleotide sequence and mRNA analysis showed that the two genes are cotranscribed in a large transcript encoding both HPr and enzyme I . The transcription of ptsHI was shown to be independent of the carbon source . Four ptsI mutants were constructed by single-crossover recombination . For all mutants, growth on PTS carbohydrates was abolished . Surprisingly, the growth rates of mutants on ribose and arabinose, two carbohydrates which are not transported by the PTS, were accelerated . This unexpected phenotype suggests that the PTS negatively controls ribose and arabinose utilization in L . sake by a mechanism different from the regulation involving HPr described for other gram-positive bacteria.

J Bacteriol, 1997 Jun, 179(11), 3804 - 7
The alanine racemase gene is essential for growth of Lactobacillus plantarum; Hols P et al.; The Lactobacillus plantarum alr gene encoding alanine racemase was cloned by complementation of an Escherichia coli Alr- DadX- double mutant strain . Knockout of the alr gene abolished all measurable alanine racemase activity, and the mutant was shown to be strictly dependent on D-alanine for growth.

Ginecol Obstet Mex, 1997 May, 65, 182 - 90
{Bacterial vaginosis . Relation between the vaginal flora and the vaginal epithelial cells under different treatments . Ultrastructural study}; Flores Rivera E et al.; At this study we analyzed morphologic relation with vaginal ephitelium, in women with bacterial vaginosis, in pre-treatment; first post-treatment and second post-treatment using metronidazol (oral), and clindamycine (intra-vaginally) . From 20 patients with bacterial vaginosis, 10 received oral metronidazol, 500 mg/b.i.d . during seven days; the other patients received, clindamycine 2% intravaginal, once a day, during seven days . Couples received metronidazol . In pre-treatment, cellular prolongations produced greater adhesion of bacteria, and rests of cellular unions with adhered bacteria . There was penetration of some bacteria to epithelial cells, confirming this with serial cuts and discarding superposition in the cells . This penetration was found in five cases y persisted during the first and second post-treatment . In the first post-treatment, cellular groups without bacteria, were found . The presence of lactobacillus was low, increasing afterwards . The presence of yeasts was in the first post-treatment, and in some cases persisted . It is important to differentiate intracellular bacteria and to know the related characteristics with bacterial penetration, for an adequate prescription and a better use of medication, avoiding possible damage . The presence of bacteria may be one of the causes for bacterial vaginosis reincidence.

Jpn J Antibiot, 1997 May, 50(5), 474 - 8
{Intravaginal bacterial flora and clinical significance of granulocyte elastase and pH determination}; Chimura T; In 95 patients with abnormal vaginal and cervical secreta (49 pregnant women and 46 non-pregnant women), the relation between intravaginal flora and intravaginal granulocyte elastase (Elastase) and pH was investigated . The results were as follows . 1) Gram-positive bacteria were detected in the vaginal secreta at a high rate (87/144, 60.4%), and it mainly consisted of Lactobacillus sp . (67/142, 46.5%) . It was followed anaerobia (26/144, 18.1%) and fungi (26/144, 18.1%) . 2) The patients with cervicitis or vaginitis had higher elastase value (6.65-6.69 micrograms/ml) than the ones with vaginal erosion, and the patients who showed an intravaginal pH value not lower than 5.0 had significantly increased elastase value (6.44 +/- 1.40 micrograms/ml) than the patients who showed the values 4.5 or higher . 3) Regarding the relation between the detected bacteria and elastase values, elastase values were higher in the patients infected by anaerobia (6.58 +/- 1.40 micrograms/ml), Gram-negative bacteria (6.01 +/- 3.61 micrograms/ml), Gram-positive bacteria (5.02 +/- 0.94 micrograms/ml) and fungi (5.14 +/- 1.08 micrograms/ml) than the values in patients with Lactobacillus sp . (pH < 4.5) . Further, the intravaginal pH value was higher than 4.5 in all of these groups, which was higher compared with the one in the patients infected with Lactobacillus sp . (4.04 +/- 0.04).

Appl Microbiol Biotechnol, 1997 May, 47(5), 537 - 42
Protein A as a fusion partner for the expression of heterologous proteins in Lactobacillus; Rush C et al.; An expression system based on the Staphylococcus aureus protein A gene (spa) was developed to allow the production and export of proteins in Lactobacillus . Plasmid shuttle vectors were constructed that carried the eZZ gene, a synthetic gene based on the Protein A gene (spa) but lacking the carboxy-terminal membrane-anchoring region . A gene fusion was created between the eZZ gene and the VD4 region of a chlamydial major outer-membrane protein gene . Expression studies demonstrated the recognition of the spa regulatory signals by several Lactobacillus, with the recombinant protein being expressed (from 0.1 microgram of EZZVD4 fusion protein per ml in L . plantarum up to 10 micrograms of EZZ protein per ml in L . fermentum) and exported (levels up to 20% in L . fermentum) in several Lactobacillus strains.

J Ethnopharmacol, 1997 May, 56(3), 227 - 32
Antimicrobial activity of flavonoids from leaves of Tagetes minuta; Tereschuk ML et al.; The total extract and fractions with different solvents, obtained from leaves of Tagetes minuta, showed several degrees of antimicrobial activity against Gram positive and Gram negative microorganisms . The same fractions were inactive against Lactobacillus, Zymomonas and Saccharomices species . The major component of the extract: quercetagetin-7-arabinosyl-galactoside, showed significant antimicrobial activity on pathogen microorganisms tested . Correlation results were carried out using chloramphenicol as standard antibiotic.

Acta Paediatr, 1997 May, 86(5), 460 - 5
A trial in the Karelian Republic of oral rehydration and Lactobacillus GG for treatment of acute diarrhoea; Shornikova AV et al.; In a controlled trial in Petrozavodsk, Karelia, the effects of oral rehydration and Lactobacillus strain GG (LGG) on recovery from acute diarrhoea (27% rotavirus, 21% bacterial aetiology) were studied in 123 children aged between 1 and 36 months of age . On admission to hospital, the patients were first randomized to receive either isotonic oral rehydration solution (ORS) with osmolarity 311 mosmol/l and sodium 90 mmol/l (WHO-ORS), or a hypotonic ORS with osmolarity 224 mosmol/l and sodium 60 mmol/l (Light-ORS), and thereafter randomized to receive either 5 x 10(9) colony forming units of LGG or a matching placebo . The two ORS performed equally for acute rehydration, and oral rehydration with either ORS was associated with a shorter duration of diarrhoea than intravenous rehydration (p = 0.036) . Patients receiving LGG had a significantly shorter duration of watery diarrhoea {mean (SD) 2.7 (2.2) days} than those receiving the placebo {3.7 (2.8) days, p = 0.03} . LGG significantly shortened the duration of rotavirus diarrhoea but not diarrhoea with confirmed bacterial aetiology.

Biosci Biotechnol Biochem, 1997 May, 61(5), 884 - 6
Isolation and partial amino acid sequence of bacteriocins produced by Lactobacillus acidophilus; Tahara T et al.; Bacteriocins produced by Lactobacillus acidophilus JCM 1023, JCM 1028, JCM 1021, JCM 1229, and JCM 5342 were active against closely related lactobacilli . These bacteriocins were purified and partial sequenced . Bacteriocin activities of L . acidophilus JCM 1023 and JCM 1028 were associated with two components . On the basis of N-terminal amino acid sequencing and the molecular masses, it is interpreted that these two-component bacteriocins are identical to acidocin J1132, a bacteriocin from L . acidophilus JCM 1132 {Tahara et al., Appl . Environ . Microbiol., 62, 892-897 (1996)} . Other bacteriocins were single-peptide bacteriocins.

J Dairy Res, 1997 May, 64(2), 271 - 80
Monitoring the microbiology of high quality milk by monthly sampling over 2 years; Desmasures N et al.; The concentrations of seven types of microorganism in the milk produced by farms using high quality milking procedures were monitored monthly . The most commonly encountered bacterium was Pseudomonas, whose concentration varied greatly between samples, but lactococci, lactobacilli and yeasts were also present at more stable concentrations . Staphylococcus aureus and beta-glucuronidase-positive Escherichia coli were occasionally detected . Listeria monocytogenes was found in the samples from only one farm, while Yersinia enterocolitica was never detected . There were seasonal variations in the concentrations of lactobacilli and yeasts over the 2 years monitored . The changes in certain bacteria (Lactococcus, Lactobacillus) on any given farm were very similar from one year to the next . The microbiological characteristics of the milk from the farms examined seemed to be fairly constant . The profiles of some bacteria used for cheesemaking were relatively stable over time . It thus seems that the milk provided by different producers could be typed.

J Bacteriol, 1997 May, 179(10), 3362 - 4
Exchange of glutamate and gamma-aminobutyrate in a Lactobacillus strain; Higuchi T et al.; Lactobacillus sp . strain E1 catalyzed the decarboxylation of glutamate (Glu), resulting in a nearly stoichiometric release of the products gamma-aminobutyrate (GABA) and CO2 . This decarboxylation was associated with the net synthesis of ATP . ATP synthesis was inhibited almost completely by nigericin and about 70% by N,N'-dicyclohexylcarbodiimide (DCCD), without inhibition of the decarboxylation . These findings are consistent with the possibility that a proton motive force arises from the cytoplasmic proton consumption that accompanies glutamate decarboxylation and the electrogenic Glu/GABA antiporter and the possibility that this proton motive force is coupled with ATP synthesis by DCCD-sensitive ATPase.

J Bacteriol, 1997 May, 179(10), 3310 - 6
Identification and characterization of a basic cell surface-located protein from Lactobacillus fermentum BR11; Turner MS et al.; Extraction of Lactobacillus fermentum BR11 cells with 5 M LiCl yielded a preparation containing a single predominant polypeptide with an apparent molecular mass of 32 kDa . A clone encoding an immunoreactive 32-kDa polypeptide was isolated from a pUC18 library of L . fermentum BR11 DNA by screening with an antiserum raised against whole cells of L . fermentum BR11 . Sequence determination of the insert in the clone revealed a complete 795-bp open reading frame (ORF) that defines a 28,625-Da polypeptide (BspA) . N-terminal sequencing of the LiCl-extracted polypeptide from L . fermentum BR11 confirmed that it is the same as the cloned BspA . BspA was found to have a sequence similar to those of family III of the bacterial solute-binding proteins . The sequences of two ORFs upstream of bspA are consistent with bspA being located in an operon encoding an ATP-binding cassette-type uptake system . Unusually, BspA contains no lipoprotein cleavage and attachment motif (LXXC), despite its origin in a gram-positive bacterium . Biotin labelling and trypsin digestion of whole cells indicated that this polypeptide is exposed on the cell surface . The isoelectric point as predicted from the putative mature sequence is 10.59 . It was consequently hypothesized that the positively charged BspA is anchored by electrostatic interaction with acidic groups on the cell surface . It was shown that BspA could be selectively removed from the surface by extraction with an acidic buffer, thus supporting this hypothesis.

Appl Environ Microbiol, 1997 May, 63(5), 1939 - 44
Molecular characterization of an inducible p-coumaric acid decarboxylase from Lactobacillus plantarum: gene cloning, transcriptional analysis, overexpression in Escherichia coli, purification, and characterization; Cavin JF et al.; By using degenerate primers designed from the first 19 N-terminal amino acids of Lactobacillus plantarum p-coumaric acid decarboxylase (PDC), a 56-bp fragment was amplified from L . plantarum in PCRs and used as a probe for screening an L . plantarum genomic bank . Of the 2,880 clones in the genomic bank, one was isolated by colony hybridization and contained a 519-bp open reading frame (pdc gene) followed by a putative terminator structure . The pdc gene is expressed on a monocistronic transcriptional unit, which is transcribed from promoter sequences homologous to Lactococcus promoter sequences . No mRNA from pdc and no PDC activity were detected in uninduced cell extracts, indicating that the expression is transcriptionally regulated by p-coumaric acid, which corresponds to an activation factor up to 6,000 . The pdc gene was overexpressed constitutively in Escherichia coli, and the recombinant enzyme was purified and characterized.

Appl Environ Microbiol, 1997 May, 63(5), 1725 - 31
Cell surface characteristics of Lactobacillus casei subsp . casei, Lactobacillus paracasei subsp . paracasei, and Lactobacillus rhamnosus strains; Pelletier C et al.; Hydrophilic and electrostatic cell surface properties of eight Lactobacillus strains were characterized by using the microbial adhesion to solvents method and microelectrophoresis, respectively . All strains appeared relatively hydrophilic . The strong microbial adhesion to chloroform, an acidic solvent, in comparison with microbial adhesion to hexadecane, an apolar n-alkane, demonstrated the particularity of lactobacilli to have an important electron donor and basic character and consequently their potential ability to generate Lewis acid-base interactions with a support . Regardless of their electrophoretic mobility (EM), strains were in general slightly negatively charged at alkaline pH . A pH-dependent behavior concerning cell surface charges was observed . The EM decreased progressively with more acidic pHs for the L . casei subsp . casei and L . paracasei subsp . paracasei strains until the isoelectric point (IEP), i.e., the pH value for which the EM is zero . On the other hand, the EM for the L . rhamnosus strains was stable from pH 8 to pH 3 to 4, at which point there was a shift near the IEP . Both L . casei subsp . casei and L . paracasei subsp . paracasei strains were characterized by an IEP of around 4, whereas L . rhamnosus strains possessed a markedly lower IEP of 2 . The present study showed that the cell surface physicochemical properties of lactobacilli seem to be, at least in part and under certain experimental conditions, particular to the bacterial species . Such differences detected between species are likely to be accompanied by some particular changes in cell wall chemical composition.

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