Curr Issues Mol Biol, 2000 Jan, 2(1), 17 - 25 Lactic acid bacteria as live vaccines; Mercenier A et al.; Mucosal routes for vaccine delivery offer several advantages over systemic inoculation from both immunological and practical points of view . The development of efficient mucosal vaccines therefore represents a top prority in modern vaccinology . One way to deliver protective antigens at the mucosal surfaces is to use live bacterial vectors . Until recently most of these were derived from attenuated pathogenic microorganisms . As an alternative to this strategy, non-pathogenic food grade bacteria such as lactic acid bacteria (LAB) are being tested for their efficacy as live antigen carriers . The LABVAC european research network is presently comparing the vaccine potential of Lactococcus lactis, Streptococcus gordonii and Lactobacillus spp . To date, it has been shown that systemic and mucosal antigen-specific immune responses can be elicited in mice through the nasal route using the three LAB systems under study . Data on successful oral and vaginal immunisations are also accumulating for L . lactis and S . gordonii, respectively . Moreover, the immune responses can be potentiated by co-expression of interleukins . Future areas of research include improvement of local immunisation efficiency, analysis of in vivo antigen production, unravelling of the Lactobacillus colonisation mechanisms and construction of biologically contained strains. Med Hypotheses, 2001 Aug, 57(2), 252 - 7 Lactobacilli-mediated control of vaginal cancer through specific reactive oxygen species interaction; Bauer G; Klebanoff et al . proposed that hydrogen peroxide-producing lactobacilli and peroxidase in the vagina of healthy women might be responsible for the prevention of vaginosis and also might exert an antitumor effect (1) . Based on recent evidence on superoxide anion generation by transformed cells (2,3) and on the potential of myeloperoxidase for selective apoptosis induction in transformed cells (4), a model for specific reactive oxygen species interaction during lactobacilli-mediated tumor control in the vagina is presented here.We propose that peroxidase, which converts hydrogen peroxide into hypochlorous acid, is responsible for creating a microbicidal vaginal milieu by maintaining a balanced, non-toxic, steady state level of the microbicides H(2)O(2)and HOCI . In case individual superoxide anion-producing transformed cells eventually appear in the mucosa they will be driven into apoptosis by interaction of HOCI with superoxide anions which leads to the generation of hydroxyl radicals . Hence selective apoptosis induction in transformed cells represents the key element of lactobacilli-mediated antitumor defense . Since papilloma virus infected cells are resistant to this pathway of apoptosis induction, they are plausible candidates for circumvention of lactobacilli-mediated control of oncogenesis . J Clin Dent, 2000, 11(2), 42 - 6 Effect of chlorhexidine varnish on bacterial levels in plaque and saliva during orthodontic treatment; Madlena M et al.; The plaque-retentive effects of fixed orthodontic appliances may induce a rapid increase in the amount of plaque . The aim of the present study was to conduct a longitudinal clinical investigation on the antibacterial effect of chlorhexidine-containing Cervitec varnish during orthodontic treatment . Twenty-four subjects (9 male, 15 female), aged 16.5 +/- 2.5 years, participated in the study . At baseline, the subjects' DMF-S scores, stimulated salivary flow rates (ml/min) and levels of salivary Streptococcus mutans (SM) and lactobacilli (LB) were determined using Dentocult SM strip and Dentocult LB methods . After placing the orthodontic appliances, the subjects were treated with Cervitec or a placebo varnish around the bands and brackets . The chlorhexidine varnish was applied randomly in the first or second quadrant, and placebo varnish in the opposite quadrant, according to the split-mouth technique . The varnish application was repeated every 3 months to the same sites . Follow-up samples of saliva and plaque from around brackets and bands were collected at 1, 3, 6, 9 and 12 months . Plaque SM and salivary SM, as well as LB counts were determined as at baseline . The results showed that a significantly higher proportion of plaque samples belonged to the low-risk category (SM count10(5) CFU/ml) on the test side than on the placebo side . Distribution of salivary samples between the low-risk and high-risk categories (based on SM and LB counts) did not change significantly until the end of the follow-up period . The number of new carious lesions after debonding the fixed orthodontic appliance was significantly lower (p < 0.05) in the Cervitec-treated quadrant compared to the placebo varnish-treated quadrant . The results show that the chlorhexidine-containing varnish effectively reduced the number of SM in dental plaque around fixed orthodontic appliances. Sex Transm Dis, 2001 Jul, 28(7), 363 - 6 The pig-tailed macaque rectal model: microflora and chlamydial infection; Patton DL et al.; BACKGROUND: A topical microbicide should protect against acquisition of sexually transmitted infection during both vaginal and rectal intercourse . The rectal microflora of the Macaca nemestrina (pig-tailed macaque) and humans were examined, as well as the histopathology of rectal tissues . In a subset of macaques, a human rectal isolate of Chlamydia trachomatis was inoculated into the rectum to establish rectal chlamydial infection . GOAL: To evaluate the comparability of the pig-tailed macaque rectal model with humans . STUDY DESIGN: Rectal swabs were collected for microbiologic analysis to characterize normal microflora in pig-tailed macaques and humans . Subsequently, 10 macaques received a rectal inoculation with C trachomatis, serovar D, prepared from a clinical rectal isolate . RESULTS: The rectal microflora of pig-tailed macaques (n = 80) were found to be comparable with the rectal flora of humans (n = 40) . The prevalence of Lactobacillus in the rectum was higher in the macaques than in humans . Coliform and Enterococcus were decreased in the macaques, as compared with those of humans . In 9 of 10 macaques, rectal chlamydial infection was confirmed by culture or ligase chain reaction on days 2, 7, and 14 after inoculation . The test results were positive for rectal chlamydial infection by ligase chain reaction only for the remaining animal on day 14 after inoculation . CONCLUSIONS: The findings demonstrate that the rectal environment of the pig-tailed macaque is a useful model for further evaluation of newly developed topical microbicides for rectal use . Furthermore, such products can be evaluated for protection against rectal chlamydial infection in this model. J Food Prot, 2001 Jul, 64(7), 1019 - 24 Antimicrobial activity of essential oils from plants against selected pathogenic and saprophytic microorganisms; Elgayyar M et al.; The beneficial health effects of extracts from many types of plants that are used as seasoning agents in foods and beverages have been claimed for centuries . The purpose of this study was to examine the effectiveness of selected herb and spice essential oils for control of growth and survival of microorganisms . Inhibition of growth was tested by the paper disc agar diffusion method . Antibiotic susceptibility discs were used as control . Minimum lethal concentration (MLC) was determined by the tube dilution method . Essential oils from anise, angelica, basil, carrot, celery, cardamom, coriander, dill weed, fennel, oregano, parsley, and rosemary were evaluated . Inhibition ranged from complete with oregano to no inhibition with carrot oil for each of the test strains that included: Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O:157:H7, Yersinia enterocolitica, Pseudomonas aeruginosa, Lactobacillus plantarum, Aspergillus niger, Geotrichum, and Rhodotorula . Oregano essential oil showed the greatest inhibition (zone, > or = 70 to 80 mm) (MLC, approximately 8 ppm) . Coriander and basil were also highly inhibitory (MLC, approximately 25 to 50 ppm) to E . coli O:157:H7 and to the other bacteria and fungi tested . Anise oil was not particularly inhibitory to bacteria (inhibition zone, approximately 25 mm); however, anise oil was highly inhibitory to molds . Because some of the herbal and spice essential oils are highly inhibitory to selected pathogenic and spoilage microorganisms, they may provide alternatives and supplements to conventional antimicrobial additives in foods. Chem Pharm Bull (Tokyo), 2001 Jul, 49(7), 918 - 20 New paeonilactone-A adducts formed by anaerobic incubation of paeoniflorin with Lactobacillus brevis in the presence of arylthiols; Abdel-Hafez AA et al.; During the course of preparing anticonvulsant paeonimetabolin-I adducts, new paeonilactone-A adducts: 9-phenylthiopaeonilactone-A, 9-(o-tolylthio)paeonilactone-A, 9-(m-tolylthio)paeonilactone-A, 9-(p-tolylthio)-paeonilactone-A and 9-(2-naphthylthio)paeonilactone-A, were obtained along with expected paeonimetabolin-I adducts by anaerobic incubation of paeoniflorin from peony roots with Lactobacillus brevis in the presence of the aromatic thiols, phenylthiol, o-tolylthiol, m-tolylthiol, p-tolylthiol and 2-naphthylthiol . The structures of these compounds were determined by spectroscopic methods including two dimensional (2D) NMR. J Perinat Med, 2001, 29(3), 199 - 211 A simple, efficient and inexpensive program for preventing prematurity; Saling E et al.; Prevention of prematurity and of low birth weight is--because of the associated increased risk of mortality and morbidity--one of the most urgent tasks of perinatal medicine . Whereas the rate of prematures all over the world does not vary very much (5-10%), the rate of infants born with low birth weight lies between 3.6% and 10% in the industrial countries and between 9.8% and 43% in the developing countries, where the main cause of low birth weight is intrauterine malnutrition . As there are different causes for prematurity and low birth weight, but also because various countries have different resources and have therefore to set their priorities differently, there is no global solution . The situation in each country must be considered individually . However, as far as basic means are available for the majority--such as basic health care, monitoring the nutritional state of the mothers and acting to prevent infectious diseases (malaria in particular can cause prematurity)--determined prevention of prematurity should take the form of screening and the treatment of disturbances of the vaginal milieu or genital infections . This policy can be recommended because one of the most important avoidable causes of prematurity is ascending genital infection (mostly combined with bacterial vaginosis), which very frequently starts with a disturbance of the vaginal milieu and then often takes its course asymptomatically . Regular screening for signs of such a disturbance using vaginal pH-measurements (and if necessary further diagnostics and therapy) makes possible the detection of an "early marker" to prevent prematurity in an effective and inexpensive way . Our prematurity-prevention-program, which has been successful for many years, is based on an anamnestic assessment of prematurity risk, the early detection of warning signs (including regular measurement of the vaginal pH) and, if necessary, the appropriate therapeutic measures . In cases of disturbance of the vaginal milieu, the latter consists of a therapy with lactobacillus preparations or in a combination of lactobacillus preparation with an acidifying therapy which may lead to earlier normalization of the vaginal milieu . In cases of bacterial vaginosis local therapy, for example with metronidazol or clindamycin, is undertaken, and in other infections specific treatment . It is encouraging to note that particularly the rate of the very small prematures is reduced when pregnant patients take part in our self-care-program, measuring their own vaginal pH-value twice a week, and also searching for any other warning signs . In this way in our collective the rate of very small low birth weight infants could be reduced from 7.8% in the immediate previous pregnancy to 1.3% . In a prospective study performed in Erfurt the rate of very early premature births (< 32 + 0 gw) amounted to only 0.3% in contrast to 3.3% in a control group who had not taken part in the self-care activity . According to a differentiated classification of the control group the success of the self-care activity was even clearer: In patients who did not take part because their doctors did not support the self-care activity, the rate of very early premature births amounted to 4.1% . In patients who did not take part in the self-care activity, but who were in the care of doctors who were interested and had taken part in the prevention-program, the rate was 2.2%; in the group with active participation in the self-care activity it was only 0.3% . To date measurement of the vaginal pH-value was performed intravaginally using either indicator strips or pH-measuring test gloves . A short time ago we developed a panty liner coated with an indicator strip, which enables reading of the pH-value by just checking the indicator on the panty liner . First results with this panty liner are very promising. Lett Appl Microbiol, 2001 Jul, 33(1), 26 - 30 RAPD-PCR characterization of lactobacilli isolated from artisanal meat plants and traditional fermented sausages of Veneto region (Italy); Andrighetto C et al.; AIMS: The study was carried out to evaluate the use of randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) as a method for the identification of lactobacilli isolated from meat products . METHODS AND RESULTS: RAPD-PCR with primers M13 and D8635 was applied to the identification and intraspecific differentiation of 53 lactobacilli isolates originating from traditional fermented sausages and artisanal meat plants of the Veneto region (Italy) . Most of the isolates were assigned to the species Lactobacillus sakei and Lact . curvatus; differentiation of groups of strains within the species was also possible . CONCLUSION: RAPD-PCR could be applied to the identification of lactobacilli species most commonly found in meat products . SIGNIFICANCE AND IMPACT OF THE STUDY: The method, which is easy and rapid to perform, could be useful for the study of the lactobacilli populations present in fermented sausages, and could help in the selection of candidate strains to use as starter cultures in meat fermentation. J Appl Microbiol, 2001 Jul, 91(1), 160 - 7 Effect of galactose and glucose on the exopolysaccharide production and the activities of biosynthetic enzymes in Lactobacillus casei CRL 87; Mozzi F et al.; AIMS: The objective of this work was to study the influence of the sugar source on exopolysaccharide (EPS) production and the activities of the enzymes involved in the synthesis of sugar nucleotides in Lactobacillus casei CRL 87 . The relationship between these enzymes and EPS formation was determined . METHODS AND RESULTS: The concentration of EPS was estimated by the phenol/sulphuric acid method while the chemical composition of purified EPS was investigated using gas-liquid chromatography . Biosynthetic enzyme activities were determined spectrophotometrically by measuring the formation or disappearance of NAD(P)H at 340 nm . Polysaccharide production by Lb . casei CRL 87 was 1.7 times greater on galactose than on glucose . The isolated polymer was composed of rhamnose, glucose and galactose . The activities of uridine-diphosphate (UDP)-glucose-pyrophosphorylase, thymidine-diphosphate (dTDP)-glucose-pyrophosphorylase and the dTDP-rhamnose-synthetic enzyme system were higher in galactose-grown than in glucose-grown cells . When an EPS- mutant strain was used, galactokinase activity was not detected on galactose, this sugar not being available for the formation of sugar nucleotides for further EPS production . dTDP-glucose-pyrophosphorylase and dTDP-rhamnose-synthetic enzyme system activities were lower than the values found for the wild type strain . CONCLUSION: The carbon source present in the culture medium affects EPS production by Lb . casei CRL 87 . The greater polymer synthesis by galactose-grown cells is correlated with the higher UDP-glucose-pyrophosphorylase, dTDP-glucose-pyrophosphorylase and dTDP-rhamnose-synthetic enzyme system activities . Initial sugar metabolism is also an important step for the synthesis of EPS precursors by this strain . SIGNIFICANCE AND IMPACT OF THE STUDY: Knowledge of the effect of the sugar source on EPS production and the activities of biosynthetic enzymes provides information about the mechanisms of regulation of the synthesis of EPS which can contribute to improving polymer production. J Appl Microbiol, 2001 Jul, 91(1), 131 - 8 An analysis of bacteriocins produced by lactic acid bacteria isolated from malted barley; Vaughan A et al.; AIMS: The aim of this study was to perform a detailed characterization of bacteriocins produced by lactic acid bacteria (LAB) isolated from malted barley . METHODS AND RESULTS: Bacteriocin activities produced by eight LAB, isolated from various types of malted barley, were purified to homogeneity by ammonium sulphate precipitation, cation exchange, hydrophobic interaction and reverse-phase liquid chromatography . Molecular mass analysis and N-terminal amino acid sequencing of the purified bacteriocins showed that four non-identical Lactobacillus sakei strains produced sakacin P, while four Leuconostoc mesenteroides strains were shown to produce bacteriocins highly similar or identical to leucocin A, leucocin C or mesenterocin Y105 . Two of these bacteriocin-producing strains, Lb . sakei 5 and Leuc . mesenteroides 6, were shown to produce more than one bacteriocin . Lactobacillus sakei 5 produced sakacin P as well as two novel bacteriocins, which were termed sakacin 5X and sakacin 5T . The inhibitory spectrum of each purified bacteriocin was analysed and demonstrated that sakacin 5X was capable of inhibiting the widest range of beer spoilage organisms . CONCLUSION: All bacteriocins purified in this study were class II bacteriocins . Two of the bacteriocins have not been described previously in the literature while the remaining purified bacteriocins have been isolated from environments other than malted barley . SIGNIFICANCE AND IMPACT OF THE STUDY: This study represents a thorough analysis of bacteriocin-producing LAB from malt and demonstrates, for the first time, the variety of previously identified and novel inhibitory peptides produced by isolates from this environment . It also highlights the potential of these LAB cultures to be used as biological controlling agents in the brewing industry. Scand J Infect Dis, 2001, 33(5), 344 - 9 Antibacterial susceptibility of intestinal lactobacilli of healthy children; Mandar R et al.; We investigated the antibacterial susceptibility of intestinal lactobacilli of Estonian and Swedish children aged 1-2 y . Sixty isolates (10 species) of lactobacilli (29 Estonian and 31 Swedish strains) were tested against ampicillin, cefuroxime, cefoxitin, gentamicin, ciprofloxacin, tetracycline, vancomycin, metronidazole and erythromycin . We observed that intestinal lactobacilli do not display uniform susceptibility to antibiotics . None of the tested lactobacilli was resistant to ampicillin, gentamicin and erythromycin . Single strains were resistant to cefuroxime and tetracycline, about half of the strains to cefoxitin and ciprofloxacin and 73% of the strains to vancomycin . All studied strains were resistant to metronidazole . Most of the strains investigated were resistant to two or three antibiotics out of nine . Some differences in susceptibility were noted between strains belonging to different fermentation types . No differences in susceptibility were found between Estonian and Swedish isolates . Metronidazole, cefoxitin, vancomycin and ciprofloxacin seem to be safer for gastrointestinal lactoflora than other tested antibiotics in both countries. Scand J Immunol, 2001 Jul-Aug, 54(1-2), 109 - 16 Inhibitory effects of MoAbs against a surface protein antigen in real-time adherence in vitro and recolonization in vivo of Streptococcus mutans; Senpuku H et al.; A surface protein antigen (PAc) of Streptococcus mutans, particularly the A-region of the molecule, has been reported to interact with salivary components on the tooth surface . It might be a candidate antigen inducing the production of antibodies against the adherence of S . mutans to the tooth surface . We investigated the effects of monoclonal antibodies (MoAbs) obtained by immunization of synthetic PAc peptides that completely correspond to the amino acid sequence of part of the A-region . These MoAbs recognize several core B-cell epitopes in the sequence . Two (KH5 and SH2) of these antibodies reacted with both S . mutans and Streptococcus sobrinus, but not with Streptococcus sanguis, Streptococcus salivarius, Porphyromonas gingivalis or Lactobacillus casei . They clearly inhibited the real-time adherence of S . mutans to salivary components in a biosensor . KH5, which showed a real-time inhibition (71%), also significantly prevented the recolonization of S . mutans on the tooth surface in rats . These results suggested that the core B-cell epitope (-Y---L--Y----) recognized by KH5 was the essential sequence in the antigenic epitopes of PAc protein recognized specifically by the inhibitory antibody . Therefore, the amino acid residues were found to be important in the initial attachment of S . mutans to the tooth surface . These results provide for the mechanism of PAc molecule in the initial attachment of S . mutans on the tooth surface and more effective designs for the removal of S . mutans and S . sobrinus from the oral cavity. J Microbiol Methods, 2001 Sep, 46(3), 227 - 33 Determination of the growth stages of Lactobacillus paracasei subsp . paracasei M3 from Bulgarian yellow cheese by electroconductivity; Atanassova MR et al.; The growth curve and the bacteriocin production by Lactobacillus paracasei subsp . paracasei M3-a strain isolated from Bulgarian yellow cheese, was studied using electroconductivity measurements in the culture medium (MRS) . The bacteriocin produced by this bacterium inhibits strains belonging to the Candida species as well as Bacillus subtilis ATCC 6633.The use of the direct impedance technique coupled with statistical treatment of the results for the strain's growth curve allowed the detection of the growth phase-related bacteriocin production . Definition of the average particle size and aggregation estimations for the cells of the bacteriocin-producing strain was also possible . The comparison of results of impedance measurements with results obtained by classic microbiological methods and microscopic observations confirms the good correlation between these methods . In addition, the advantages of an impedance method such as rapidity, simplicity and higher sensitivity are highlighted. BMJ . 2001 Jun 30;322(7302):1571. Randomised trial of cranberry-lingonberry juice and Lactobacillus GG drink for the prevention of urinary tract infections in women; Kontiokari T et al.; OBJECTIVE: To determine whether recurrences of urinary tract infection can be prevented with cranberry-lingonberry juice or with Lactobacillus GG drink . Design: Open, randomised controlled 12 month follow up trial . SETTING: Health centres for university students and staff of university hospital . PARTICIPANTS: 150 women with urinary tract infection caused by Escherichia coli randomly allocated into three groups . Interventions: 50 ml of cranberry-lingonberry juice concentrate daily for six months or 100 ml of lactobacillus drink five days a week for one year, or no intervention . Main outcome measure: First recurrence of symptomatic urinary tract infection, defined as bacterial growth >/=10(5 )colony forming units/ml in a clean voided midstream urine specimen . RESULTS: The cumulative rate of first recurrence of urinary tract infection during the 12 month follow up differed significantly between the groups (P=0.048) . At six months, eight (16%) women in the cranberry group, 19 (39%) in the lactobacillus group, and 18 (36%) in the control group had had at least one recurrence . This is a 20% reduction in absolute risk in the cranberry group compared with the control group (95% confidence interval 3% to 36%, P=0.023, number needed to treat=5, 95% confidence interval 3 to 34) . CONCLUSION: Regular drinking of cranberry juice but not lactobacillus seems to reduce the recurrence of urinary tract infection. Obstet Gynecol, 2001 Jul, 98(1), 79 - 84 Nugent score related to vaginal culture in pregnant women; Delaney ML et al.; OBJECTIVE: To relate Gram-stained smears, using the Nugent criteria, to quantitative and qualitative vaginal cultures in pregnant women . METHODS: Two independent evaluators using the Nugent criteria, a standardized method of Gram-stain interpretation designed to detect bacterial vaginosis, scored 104 vaginal smears from pregnant women . The quantitative and qualitative vaginal cultures were assessed at the same time and the results expressed as log(10) colony-forming units per gram of vaginal secretion . The Nugent scores were compared with the microbiologic findings . RESULTS: The prevalence of normal, intermediate, or bacterial vaginosis vaginal flora as determined by Gram stain was 68%, 21%, and 11%, respectively . A comparison of the mean bacterial counts with the Nugent score showed a weak negative correlation for Lactobacillus species and a positive correlation for gram-variable and gram-negative rods . Additional analysis revealed a strong positive correlation between the mean bacterial counts analyses of Peptostreptococcus, a genus not included in the Nugent scoring system, and the Nugent score . In addition, the Prevotella counts correlated strongly with both the Nugent score and the Peptostreptococcus counts . The quantitative counts for Lactobacillus did not vary significantly among the three defined groups of vaginal microflora; however, significant increases in the concentrations of Gardnerella vaginalis and Prevotella were found as the Nugent score increased . CONCLUSION: A strong correlation was found among the gram-variable and gram-negative genera comprised by the Nugent score . Peptostreptococcus also correlated strongly with the Nugent score and with the Prevotella counts, suggesting that this genus may play a role in determining vaginal health. Br J Nutr, 2001 Jun, 85(6), 699 - 703 Feeding dried purple laver (nori) to vitamin B12-deficient rats significantly improves vitamin B12 status; Takenaka S et al.; To clarify the bioavailability of vitamin B12 in lyophylized purple laver (nori; Porphyra yezoensis), total vitamin B12 and vitamin B12 analogue contents in the laver were determined, and the effects of feeding the laver to vitamin B12-deficient rats were investigated . The amount of total vitamin B12 in the dried purple laver was estimated to be 54.5 and 58.6 (se 5.3 and 7.5 respectively) microg/100 g dry weight by Lactobacillus bioassay and chemiluminescent assay with hog intrinsic factor respectively . The purple laver contained five types of biologically active vitamin B12 compounds (cyano-, hydroxo-, sulfito-, adenosyl- and methylcobalamin), in which the vitamin B12 coezymes (adenosyl- and methylcobalamin) comprised about 60 % of the total vitamin B12 . When 9-week-old vitamin B12-deficient rats, which excreted substantial amounts of methylmalonic acid (71.7(se 20.2) micromol/d) in urine, were fed the diet supplemented with dried purple laver (10 microg/kg diet) for 20 d, urinary methylmalonic acid excretion (as an index of vitamin B12 deficiency) became undetectable and hepatic vitamin B12 (especially adenosylcobalamin) levels were significantly increased . These results indicate that vitamin B12 in dried purple laver is bioavailable to rats. Microbiology, 2001 Jul, 147(Pt 7), 1863 - 73 The acid-stress response in Lactobacillus sanfranciscensis CB1; De Angelis M et al.; Lactobacillus sanfranciscensis CB1, an important sourdough lactic acid bacterium, can withstand low pH after initial exposure to sublethal acidic conditions . The sensitivity to low pH varied according to the type of acid used . Treatment of LB: sanfranciscensis CB1 with chloramphenicol during acid adaptation almost completely eliminated the protective effect, suggesting that induction of protein synthesis was required for the acid-tolerance response . Two constitutively acid-tolerant mutants, CB1-5R and CB1-7R, were isolated using natural selection techniques after sequential exposure to lactic acid (pH 3.2) . Two-dimensional gel electrophoresis analysis of protein expression by non-adapted, acid-adapted and acid-tolerant mutant cells of LB: sanfranciscensis showed changes in the levels of 63 proteins . While some of the modifications were common to the acid-adapted and acid-tolerant mutant cells, several differences, especially regarding the induced proteins, were determined . The two mutants showed a very similar level of protein expression . Antibodies were used to identify heat-shock proteins DnaJ, DnaK, GroES and GrpE . Only GrpE showed an increased level of expression in the acid-adapted and acid-tolerant mutants as compared with non-adapted cells . The N-terminal sequence was determined for two proteins, one induced in both the acid-adapted and mutant cells and the other showing the highest induction factor of those proteins specifically induced in the acid-adapted cells . This second protein has 60% identity with the N-terminal portion of YhaH, a transmembrane protein of Bacillus subtilis, which has 54 and 47% homology with stress proteins identified in Listeria monocytogenes and Bacillus halodurans . The constitutively acid-tolerant mutants showed other different phenotypic features compared to the parental strain: (i) the aminopeptidase activity of CB1-5R decreased and that of CB1-7R markedly increased, especially in acid conditions; (ii) the growth in culture medium at 10 degrees C and in the presence of 5% NaCl was greater (the same was found for acid-adapted cells); and (iii) the acidification rate during sourdough fermentation in acid conditions was faster and greater. J Pharm Pharmacol, 2001 Jun, 53(6), 895 - 900 Azo-containing urethane analogues for colonic drug delivery: synthesis, characterization and in-vitro evaluation; Chavan MS et al.; A urethane-based analogue containing an azo aromatic linkage in the backbone was synthesized for use in colon-specific delivery systems by reacting toluene-2,6-diisocyanate with a mixture of an aromatic azo diol, (bis-4-hydroxyphenyl)-4,4'-diazobiphenyl, poly(ethylene glycol) (Mn = 4000; number-average molecular weight) and 1,2-propanediol (propylene glycol) . The resultant compounds (UR-1 and UR-2) were characterized by IR spectroscopy, 1H NMR spectroscopy, DSC studies, X-ray diffraction studies and molecular weight determination by gel permeation chromatography . The compounds exhibited low molecular weight, lacked film-forming properties and crystallinity in the structure . An in-vitro bacterial degradation test to demonstrate the susceptibility of azo bond to bacterial enzymes was performed using media inoculated with lactobacillus culture . The results indicated degradation of films by azoreductase . In-vitro permeation of 5-aminosalicylic acid was studied in control and lactobacilli-treated films . The permeability of the lactobacilli treated films was significantly increased suggesting the potential of these compounds for application in colonic targeting. Int J Food Microbiol, 2001 Jun 15, 66(3), 197 - 203 Effects of sodium lactate and other additives in a cooked ham product on sensory quality and development of a strain of Lactobacillus curvatus and Listeria monocytogenes; Stekelenburg FK et al.; Cooked cured ham products were produced according to a standard recipe for cooked ham with various levels of sodium lactate, sodium diacetate or buffered sodium citrate . They were compared with a reference ham product with respect to sensory quality and growth of Lactobacillus curvatus and Listeria monocytogenes . For this, a part of the products was sensory analysed directly after preparation . Another part of the cooked ham products was minced and homogeneously inoculated with L . curvatus (10(4)/g) and L . monocytogenes (10(2)/g) and filled in 60-g plastic pouches . After vacuum packaging, the pouches were stored at 4 degrees C for up to 40 days . Between the different ham compositions, only minor differences were found for appearance, internal colour, structure and firmness . The addition of 0.2% Na-diacetate had a negative effect on the odour and taste of the ham product . The addition of 2.5% to 3.3% Na-lactate inhibited the growth of L . curvatus compared to the reference, while 0.1% and 0.2% Na-diacetate did not . L . monocytogenes was best inhibited by the addition of Na-lactate but also by the addition of 0.2% Na-diacetate . On the other hand, the growth of L . monocytogenes was stimulated by the addition of 1% buffered Na-citrate. Int J Food Microbiol, 2001 Jun 15, 66(3), 191 - 6 Industrial application of an antilisterial strain of Lactobacillus sakei as a protective culture and its effect on the sensory acceptability of cooked, sliced, vacuum-packaged meats; Bredholt S et al.; The application of a protective lactic acid bacterium (LAB) during the commercial production of cooked meat products is described . The LAB, a strain of Lactobacillus sakei, was previously isolated from cooked ham and inhibited growth of Listeria monocytogenes and Escherichia coli O157:H7 in this product . L . sakei was applied to the cooked products at a concentration of 10(5)-10(6) cfu/g immediately before slicing and vacuum-packaging using a hand-operated spraying bottle . The LAB strain inhibited growth of 10(3) cfu/g of a cocktail of three rifampicin resistant mutant L . monocytogenes strains both at 8 degrees C and 4 degrees C . Consumer acceptance tests of cooked ham and of servelat sausage, a Norwegian non-fermented cooked meat sausage, showed that control and inoculated products were equally acceptable . The products were still acceptable after storage for 28 days at 4 degrees C and, after opening the packages, for a further 5 days at 4 degrees C . The findings presented here confirm that the L . sakei strain is suitable for use as a protective culture and may technically easily be implemented in the commercial production of cooked meat products. J Biol Chem, 2001 Sep 7, 276(36), 33488 - 94 Epub 2001 Jun 26. The anaerobic ribonucleotide reductase from Lactococcus lactis . Interactions between the two proteins NrdD and NrdG; Torrents E et al.; Deoxyribonucleotide synthesis by anaerobic class III ribonucleotide reductases requires two proteins, NrdD and NrdG . NrdD contains catalytic and allosteric sites and, in its active form, a stable glycyl radical . This radical is generated by NrdG with its {4Fe-4S}(+) cluster and S-adenosylmethionine . We now find that NrdD and NrdG from Lactobacillus lactis anaerobically form a tight alpha(2)beta(2) complex, suggesting that radical generation by NrdG and radical transfer to the specific glycine residue of NrdD occurs within the complex . Activated NrdD was separated from NrdG by anaerobic affinity chromatography on dATP-Sepharose without loss of its glycyl radical . NrdD alone then catalyzed the reduction of CTP with formate as the electron donor and ATP as the allosteric effector . The reaction required Mg(2+) and was stimulated by K(+) but not by dithiothreitol . Thus NrdD is the actual reductase, and NrdG is an activase, making class III reductases highly similar to pyruvate formate lyase and its activase and suggesting a common root for the two anaerobic enzymes during early evolution . Our results further support the contention that ribonucleotide reduction during transition from an RNA world to a DNA world started with a class III-like enzyme from which other reductases evolved when oxygen appeared on earth. Clin Diagn Lab Immunol, 2001 Jul, 8(4), 695 - 701 Induction by a lactic acid bacterium of a population of CD4(+) T cells with low proliferative capacity that produce transforming growth factor beta and interleukin-10; von der Weid T et al.; We investigated whether certain strains of lactic acid bacteria (LAB) could antagonize specific T-helper functions in vitro and thus have the potential to prevent inflammatory intestinal immunopathologies . All strains tested induced various levels of both interleukin-12 (IL-12) and IL-10 in murine splenocytes . In particular, Lactobacillus paracasei (strain NCC2461) induced the highest levels of these cytokines . Since IL-12 and IL-10 have the potential to induce and suppress Th1 functions, respectively, we addressed the impact of this bacterium on the outcome of CD4(+) T-cell differentiation . For this purpose, bacteria were added to mixed lymphocyte cultures where CD4(+) T-cells from naive BALB/c mice were stimulated weekly in the presence of irradiated allogeneic splenocytes . In these cultures, L . paracasei NCC2461 strongly inhibited the proliferative activity of CD4(+) T cells in a dose-dependent fashion . This was accompanied by a marked decrease of both Th1 and Th2 effector cytokines, including gamma interferon, IL-4, and IL-5 . In contrast, IL-10 was maintained and transforming growth factor beta (TGF-beta) was markedly induced in a dose-dependent manner . The bacteria were not cytotoxic, because cell viability was not affected after two rounds of stimulation . Thus, unidentified bacterial components from L . paracasei NCC2461 induced the development of a population of CD4(+) T cells with low proliferative capacity that produced TGF-beta and IL-10, reminiscent of previously described subsets of regulatory cells implicated in oral tolerance and gut homeostasis. Appl Environ Microbiol, 2001 Jul, 67(7), 3092 - 101 Membrane permeabilization in relation to inactivation kinetics of Lactobacillus species due to pulsed electric fields; Wouters PC et al.; Membrane permeabilization due to pulsed electric field (PEF) treatment of gram-positive Lactobacillus cells was investigated by using propidium iodide uptake and single-cell analysis with flow cytometry . Electric field strength, energy input, treatment time, and growth phase affected membrane permeabilization of Lactobacillus plantarum during PEF treatment . A correlation between PEF inactivation and membrane permeabilization of L . plantarum cells was demonstrated, whereas no relationship was observed between membrane permeabilization and heat inactivation . The same results were obtained with a Lactobacillus fermentum strain, but the latter organism was more PEF resistant and exhibited less membrane permeabilization, indicating that various bacteria have different responses to PEF treatment . While membrane permeabilization was the main factor involved in the mechanism of inactivation, the growth phase and the acidity of the environment also influenced inactivation . By using flow cytometry it was possible to sort cells in the L . plantarum population based on different cell sizes and shapes, and the results were confirmed by image analysis . An apparent effect of morphology on membrane permeabilization was observed, and larger cells were more easily permeabilized than smaller cells . In conclusion, our results indicate that the ability of PEF treatment to cause membrane permeabilization is an important factor in determining inactivation . This finding should have an effect on the final choice of the processing parameters used so that all microorganisms can be inactivated and, consequently, on the use of PEF treatment as an alternative method for preserving food products. Appl Environ Microbiol, 2001 Jul, 67(7), 3086 - 91 Surface binding of aflatoxin B(1) by lactic acid bacteria; Haskard CA et al.; Specific lactic acid bacterial strains remove toxins from liquid media by physical binding . The stability of the aflatoxin B(1) complexes formed with 12 bacterial strains in both viable and nonviable (heat- or acid-treated) forms was assessed by repetitive aqueous extraction . By the fifth extraction, up to 71% of the total aflatoxin B(1) remained bound . Nonviable bacteria retained the highest amount of aflatoxin B(1) . Lactobacillus rhamnosus strain GG (ATCC 53103) and L . rhamnosus strain LC-705 (DSM 7061) removed aflatoxin B(1) from solution most efficiently and were selected for further study . The accessibility of bound aflatoxin B(1) to an antibody in an indirect competitive inhibition enzyme-linked immunosorbent assay suggests that surface components of these bacteria are involved in binding . Further evidence is the recovery of around 90% of the bound aflatoxin from the bacteria by solvent extraction . Autoclaving and sonication did not release any detectable aflatoxin B(1) . Variation in temperature (4 to 37 degrees C) and pH (2 to 10) did not have any significant effect on the amount of aflatoxin B(1) released . Binding of aflatoxin B(1) appears to be predominantly extracellular for viable and heat-treated bacteria . Acid treatment may permit intracellular binding . In all cases, binding is of a reversible nature, but the stability of the complexes formed depends on strain, treatment, and environmental conditions. Appl Environ Microbiol, 2001 Jul, 67(7), 2903 - 7 The functional ccpA gene is required for carbon catabolite repression in Lactobacillus plantarum; Muscariello L et al.; We report the characterization of the ccpA gene of Lactobacillus plantarum, coding for catabolite control protein A . The gene is linked to the pepQ gene, encoding a proline peptidase, in the order ccpA-pepQ, with the two genes transcribed in tandem from the same strand as distinct transcriptional units . Two ccpA transcription start sites corresponding to two functional promoters were found, expression from the upstream promoter being autogenously regulated through a catabolite-responsive element (cre) sequence overlapping the upstream +1 site . During growth on ribose, the upstream promoter showed maximal expression, while growth on glucose led to transcription from the downstream promoter . In a ccpA mutant strain, the gene was transcribed mainly from the upstream promoter in both repressing and non repressing conditions . Expression of two enzyme activities, beta-glucosidase and beta-galactosidase, was relieved from carbon catabolite repression in the ccpA mutant strain . In vivo footprinting analysis of the catabolite-controlled bglH gene regulatory region in the ccpA mutant strain showed loss of protection of the cre under repressing conditions. Scand J Gastroenterol, 2001 Jun, 36(6), 630 - 5 Effects of Lactobacillus rhamnosus GG and Lactobacillus reuteri R2LC on acetic acid-induced colitis in rats; Holma R et al.; BACKGROUND: Certain lactobacilli reduce the severity of experimental colitis . The aim of this study was to compare the effects of a human strain Lactobacillus rhamnosus GG and a rat strain Lactobacillus reuteri R2LC on acetic acid-induced colitis in rats . METHODS: Lactobacillus rhamnosus GG, Lactobacillus reuteri R2LC or sulphasalazine were given orally to the rats . Colitis was assessed 72 h after induction with acetic acid . RESULTS: Lactobacillus reuteri R2LC significantly antagonized body weight loss caused by inflammation compared with Lactobacillus rhamnosus GG and sulphasalazine, and oedema formation in the colon compared with sulphasalazine . Lactobacillus reuteri R2LC reduced the median value of macroscopic ulceration and the protein content of inducible nitric oxide synthase by 50% and the median of the protein content of inducible cyclooxygenase by 30% compared with that of the colitis control group, and Lactobacillus rhamnosus GG reduced the median of inducible nitric oxide protein content by 40% and increased the median of inducible cyclooxygenase protein content by 30% compared with the median value of the colitis control group, but these differences were not statistically significant . CONCLUSIONS: The rat strain Lactobacillus reuteri R2LC, but not the human strain Lactobacillus rhamnosus GG, is of benefit in reducing the severity of acetic acid-induced colitis in rats . These results suggest that it is not the total amount of Lactobacillus but the particular species or strain of Lactobacillus that is important in attenuating experimental colitis. Am J Trop Med Hyg, 2000 Nov-Dec, 63(5-6), 284 - 9 Use of intravaginal microbicides to prevent acquisition of Trichomonas vaginalis infection in Lactobacillus-pretreated, estrogenized young mice; Lushbaugh WB et al.; D2A21, a novel peptide antibiotic has in vitro activity against a wide spectrum of sexually transmitted diseases (STD) . In this study we tested the hypothesis that intravaginal D2A21 would interfere with acquisition of Trichomonas vaginalis infection in a modified mouse model . T . vaginalis infections of estrogenized young mice pretreated with Lactobacillus vaginalis or Lactobacillus rhamnosus were more frequent and persistent than those in mice pre-treated with Lactobacillus gasseri or Lactobacillus acidophilus . One hundred percent T . vaginalis infection was achieved for 2-4 days post-challenge when intravaginal L . rhamnosus pre-treatments were given to estrogenized mice 48 hr prior to a single T . vaginalis challenge . Estrogenized mice pre-treated with L . rhamnosus were pre-medicated with intravaginal placebo gel, 0.5% or 2% D2A21 gel, or 500 microg/mL metronidazole gel prior to T . vaginalis challenge . Both 2% D2A21 and metronidazole gels were significantly more efficacious (10% or none infected) than placebo gel (53% infected) in preventing vaginal T . vaginalis infections in mice. J Bacteriol, 2001 Jul, 183(14), 4157 - 66 Design of a protein-targeting system for lactic acid bacteria; Dieye Y et al.; We designed an expression and export system that enabled the targeting of a reporter protein (the staphylococcal nuclease Nuc) to specific locations in Lactococcus lactis cells, i.e., cytoplasm, cell wall, or medium . Optimization of protein secretion and of protein cell wall anchoring was performed with L . lactis cells by modifying the signals located at the N and C termini, respectively, of the reporter protein . Efficient translocation of precursor (approximately 95%) is obtained using the signal peptide from the lactococcal Usp45 protein and provided that the mature protein is fused to overall anionic amino acids at its N terminus; those residues prevented interactions of Nuc with the cell envelope . Nuc could be covalently anchored to the peptidoglycan by using the cell wall anchor motif of the Streptococcus pyogenes M6 protein . However, the anchoring step proved to not be totally efficient in L . lactis, as considerable amounts of protein remained membrane associated . Our results may suggest that the defect is due to limiting sortase in the cell . The optimized expression and export vectors also allowed secretion and cell wall anchoring of Nuc in food-fermenting and commensal strains of Lactobacillus . In all strains tested, both secreted and cell wall-anchored Nuc was enzymatically active, suggesting proper enzyme folding in the different locations . These results provide the first report of a targeting system in lactic acid bacteria in which the final location of a protein is controlled and biological activity is maintained. Appl Microbiol Biotechnol, 2001 May, 55(5), 596 - 603 Molecular cloning of a putative divalent-cation transporter gene as a new genetic marker for the identification of Lactobacillus brevis strains capable of growing in beer; Hayashi N et al.; Random amplified polymorphic DNA (RAPD) PCR analysis of Lactobacillus brevis isolates from breweries revealed that one of the random primers could distinguish beer-spoilage strains of L . brevis from nonspoilage strains . The 1.1-kb DNA fragment amplified from all beer-spoilers included one open reading frame, termed hitA (hop-inducible cation transporter), which encodes an integral membrane protein with 11 putative trans-membrane domains and a binding protein-dependent transport signature of a non-ATP binding membrane transporter common to several prokaryotic and eukaryotic transporters . The hitA polypeptide is homologous to the natural resistance-associated macrophage protein (Nramp) family characterized as divalent-cation transport proteins in many prokaryotic and eukaryotic organisms . Northern blot analysis indicated that the hitA transcripts are expressed in cells cultivated in MRS broth supplemented with hop bitter compounds, which act as mobile-carrier ionophores, dissipating the trans-membrane pH gradient in bacteria sensitive to the hop bitter compounds by exchanging H+ for cellular divalent cations such as Mn2+ . This suggests that the hitA gene products may play an important role in making the bacteria resistant to hop bitter compounds in beer by transporting metal ions such as Mn2+ into cells that no longer maintain the proton gradient. J Appl Microbiol, 2001 Jun, 90(6), 1015 - 8 An in vitro study of the pH-lowering potential of salivary lactobacilli associated with dental caries; Badet MC et al.; AIMS: Lactobacilli are known to produce acids from sucrose or glucose . This acid production can cause a drop in pH which is sufficiently significant to demineralize the hard tissues of the teeth . Some authors have demonstrated the benefits of substituting sorbitol or xylitol for sucrose . The aim of this work was to study the acid production of salivary lactobacilli with one test sugar (glucose) and two polyols (sorbitol and xylitol) . METHODS AND RESULTS: The pH-lowering potential of three strains of oral lactobacilli was recorded with glucose or one of the polyols at three different concentrations . The results showed that polyols were broken down by certain strains of lactobacilli . When this degradation took place, the pH dropped to values sufficiently low to demineralize the hard tissues of the teeth . CONCLUSIONS: Further studies must be carried out on the metabolism of polyols before encouraging their widespread substitution for sucrose. J Appl Microbiol, 2001 Jun, 90(6), 971 - 8 Lactobacillus casei and Lactobacillus plantarum initiate catabolism of methionine by transamination; Amarita F et al.; AIMS: To study the ability of Lactobacillus casei and Lact . plantarum strains to convert methonine to cheese flavour compounds . METHODS AND RESULTS: Strains were assayed for methionine aminotransferase and lyase activities, and amino acid decarboxylase activity . About 25% of the strains assayed showed methionine aminotransferase activity . The presence of glucose in the reaction mixture increased conversion of methionine to 4-methylthio-2-ketobutanoate (KMBA) and 4-methylthio-2-hydroxybutanoate (HMBA) in all strains . The methionine aminotransferase activity in Lact . plantarum and Lact . casei showed variable specificity for the amino group acceptors glyoxylate, ketoglutarate, oxaloacetate and pyruvate . None of the strains showed methionine lyase or glutamate and methionine decarboxylase activities . CONCLUSION: The presence of amino acid converting enzymes in lactobacilli is strain specific . SIGNIFICANCE AND IMPACT OF THE STUDY: The findings of this work suggest that lactobacilli can be used as adjuncts for flavour formation in cheese manufacture. J Appl Microbiol, 2001 Jun, 90(6), 943 - 52 Phenotypic diversity of lactic acid bacteria isolated from fermented sausages produced in Basilicata (Southern Italy); Parente E et al.; AIMS: to evaluate the evolution of lactic acid bacteria (LAB) populations in traditional fermented sausages (salsiccia and soppressata) produced in artisanal and industrial plants in Basilicata (Southern Italy) . METHODS AND RESULTS: Four hundred and fourteen lactic acid bacteria (LAB) cultures were isolated from samples of sausages at different stages of ripening . A phenotypic characterization of the isolates was carried out using a set of 28 tests, and 34 clusters were identified at the 80% similarity level using hierarchical cluster analysis . Of the isolates 50% were identified as Lactobacillus sakei (with several biotypes), 22% as Pediococcus spp . (mainly Ped . pentosaceus), 7% as Leuconostoc (Leuc . carnosum, Leuc . gelidum, Leuc . pseudomesenteroides), 6% as Lact . plantarum, 1% as Lact . curvatus . Other lactobacilli, including unidentified species, were present in lower numbers . CONCLUSION: The phenotypic diversity and composition of the LAB flora varied as a function of the production plant, product type and ripening time . SIGNIFICANCE AND IMPACT OT THE STUDY: A new procedure based on bootstrapping and Multidimensional Scaling was successfully used to obtain a graphical representation of the evolution of the LAB populations. J Appl Microbiol, 2001 Jun, 90(6), 909 - 18 Differentiation of Lactobacillus delbrueckii subspecies by ribotyping and amplified ribosomal DNA restriction analysis (ARDRA); Miteva V et al.; AIMS: To differentiate the subspecies of Lactobacillus delbrueckii, subsp . delbrueckii, subsp . lactis and subsp . bulgaricus . METHODS AND RESULTS: Amplified ribosomal DNA restriction analysis (ARDRA) and ribotyping were applied to over 30 strains . Both methods analyse the ribosomal genes which carry useful information about the evolutionary and taxonomic relationship among bacteria . The methods proved to be reliable and highly reproducible . ARDRA was applied to 16S rDNA, 23S rDNA and the IGS region, thus covering the whole rrn operon with eight restriction enzymes . Only EcoRI differentiated Lact . delbrueckii subsp . bulgaricus from Lact . delbrueckii subsp . delbrueckii/Lact . delbrueckii subsp . lactis, which confirmed the finding of other authors . Ribotyping with different enzymes under precisely optimized conditions revealed a high level of strain polymorphism . Only ribotyping with EcoRI allowed differentiation of the three subspecies on the basis of typical hybridization patterns . CONCLUSION: The successful differentiation of the three subspecies of Lact . delbrueckii by EcoRI ribotyping offers a new possibility for precise identification and differentiation of strains and new isolates . SIGNIFICANCE AND IMPACT OF THE STUDY: Both methods could be used for differentiation of Lact . delbrueckii subspecies. Int J Syst Evol Microbiol, 2001 May, 51(Pt 3), 967 - 70 Lactobacillus psittaci sp . nov., isolated from a hyacinth macaw (Anodorhynchus hyacinthinus); Lawson PA et al.; A Gram-positive, non-spore-forming, catalase-negative, facultatively anaerobic coccibacillus to rod-shaped bacterium isolated from a parrot was characterized using phenotypic and molecular taxonomic methods . The unknown bacterium phenotypically resembled lactobacilli and comparative 16S rRNA gene sequencing demonstrated that the organism represents a distinct subline within the Lactobacillus delbrueckii rRNA cluster of the genus . 16S rRNA sequence divergence values of > 6% with recognized Lactobacillus species clearly demonstrated the phylogenetic separateness of the parrot bacterium . On the basis of phylogenetic evidence and the phenotypic distinctiveness of the unknown bacterium, a new species, Lactobacillus psittaci sp . nov., is proposed . The type strain of Lactobacillus psittaci is CCUG 42378T (= CIP 106492T). FEMS Microbiol Lett, 2001 Jun 12, 200(1), 49 - 52 Protein expression under uracil privation in Lactobacillus sakei; Marceau A et al.; Lactobacillus sakei is a lactic acid bacterium belonging to the natural flora of fresh and vacuum-packed meat, and is used as the starter for manufacturing fermented sausages . This species is now being studied at the genetic level . We investigated uracil prototrophy of strain 23K in order to validate the proteomic approach to study metabolism regulations . Cells grown without uracil had lower growth rates than with uracil . Protein analysis by 2D gel electrophoresis showed that at least three polypeptides were specifically induced in the absence of uracil . Two of these polypeptides were identified as orotate phosphoribosyl transferase, catalyzing the fifth step of pyrimidine biosynthesis, and PyrR, the transcriptional regulator of the pyr operon, respectively. J Food Prot, 2001 Jun, 64(6), 777 - 82 Inactivation of Escherichia coli O1 57:H7, Listeria monocytogenes, and Lactobacillus leichmannii by combinations of ozone and pulsed electric field; Unal R et al.; Pulsed electric field (PEF) and ozone technologies are nonthermal processing methods with potential applications in the food industry . This research was performed to explore the potential synergy between ozone and PEF treatments against selected foodborne bacteria . Cells of Lactobacillus leichmannii ATCC 4797, Escherichia coli O157:H7 ATCC 35150, and Listeria monocytogenes Scott A were suspended in 0.1% NaCl and treated with ozone, PEF, and ozone plus PEE Cells were treated with 0.25 to 1.00 microg of ozone per ml of cell suspension, PEF at 10 to 30 kV/cm, and selected combinations of ozone and PEF . Synergy between ozone and PEF varied with the treatment level and the bacterium treated . L . leichmannii treated with PEF (20 kV/cm) after exposure to 0.75 and 1.00 microg/ml of ozone was inactivated by 7.1 and 7.2 log10 CFU/ml, respectively; however, ozone at 0.75 and 1.00 microg/ml and PEF at 20 kV/cm inactivated 2.2, 3.6, and 1.3 log10 CFU/ml, respectively . Similarly, ozone at 0.5 and 0.75 microg/ml inactivated 0.5 and 1.8 log10 CFU/ml of E . coli, PEF at 15 kV/cm inactivated 1.8 log10 CFU/ml, and ozone at 0.5 and 0.75 microg/ml followed by PEF (15 kV/cm) inactivated 2.9 and 3.6 log10 CFU/ml, respectively . Populations of L . monocytogenes decreased 0.1, 0.5, 3.0, 3.9, and 0.8 log10 CFU/ml when treated with 0.25, 0.5, 0.75, and 1.0 microg/ml of ozone and PEF (15 kV/cm), respectively; however, when the bacterium was treated with 15 kV/cm, after exposure to 0.25, 0.5, and 0.75 microg/ml of ozone, 1.7, 2.0, and 3.9 log10 CFU/ml were killed, respectively . In conclusion, exposure of L . leichmannii, E . coli, and L . monocytogenes to ozone followed by the PEF treatment showed a synergistic bactericidal effect . This synergy was most apparent with mild doses of ozone against L . leichmannii. Mol Microbiol, 2001 Jun, 40(5), 1175 - 86 Accumulation of manganese in Neisseria gonorrhoeae correlates with resistance to oxidative killing by superoxide anion and is independent of superoxide dismutase activity; Tseng HJ et al.; As a facultative aerobe with a high iron requirement and a highly active aerobic respiratory chain, Neisseria gonorrhoeae requires defence systems to respond to toxic oxygen species such as superoxide . It has been shown that supplementation of media with 100 microM Mn(II) considerably enhanced the resistance of this bacterium to oxidative killing by superoxide . This protection was not associated with the superoxide dismutase enzymes of N . gonorrhoeae . In contrast to previous studies, which suggested that some strains of N . gonorrhoeae might not contain a superoxide dismutase, we identified a sodB gene by genome analysis and confirmed its presence in all strains examined by Southern blotting, but found no evidence for sodA or sodC . A sodB mutant showed very similar susceptibility to superoxide killing to that of wild-type cells, indicating that the Fe-dependent SOD B did not have a major role in resistance to oxidative killing under the conditions tested . The absence of a sodA gene indicated that the Mn-dependent protection against oxidative killing was independent of Mn-dependent SOD A . As a sodB mutant also showed Mn-dependent resistance to oxidative killing, then it is concluded that this resistance is independent of superoxide dismutase enzymes . Resistance to oxidative killing was correlated with accumulation of Mn(II) by the bacterium . We hypothesize that this bacterium uses Mn(II) as a chemical quenching agent in a similar way to the already established process in Lactobacillus plantarum . A search for putative Mn(II) uptake systems identified an ABC cassette-type system (MntABC) with a periplasmic-binding protein (MntC) . An mntC mutant was shown to have lowered accumulation of Mn(II) and was also highly susceptible to oxidative killing, even in the presence of added Mn(II) . Taken together, these data show that N . gonorrhoeae possesses a Mn(II) uptake system that is critical for resistance to oxidative stress. Int J Food Sci Nutr, 2001 May, 52(3), 263 - 8 Characterization of vitamin B12 compounds from edible shellfish, clam, oyster, and mussel; Watanabe F et al.; Vitamin B12 content of various edible shellfish was determined by both Lactobacillus leichmannii ATCC 7830 microbiological and intrinsic factor-chemiluminescence methods . The values determined by the microbiological method were 1.2-19.8 (M/C ratio) fold greater in the shellfish than the values determined by the chemiluminescence method . Vitamin B12 compounds were purified from most eaten shellfish, oyster (M/C, 1.5), mussel (M/C, 1.2), and short-necked clam (M/C, 2.7), and partially characterized . TLC and HPLC patterns of each red-colored vitamin B12 compound (M/C, 1.0-1.2) purified from these shellfish were identical to those of authentic vitamin B12 . Although the higher values in the determination of vitamin B12 by the microbiological method may be due to the occurrence of vitamin B12-substitutive compounds, the edible shellfish would be excellent vitamin B12 sources judging from the values (> or = 6 micrograms/100 g) determined by the chemiluminescence method. APMIS, 2001 Feb, 109(2), 147 - 54 The effect of oral bacteria on Candida albicans germ-tube formation; Nair RG et al.; A total of eight bacterial isolates belonging to six species, and a select group of 12 oral Candida albicans isolates, were used to study the effect of bacteria on germ-tube formation . Briefly, each bacterial suspension (10(5-6) cells/ml) was mixed with a C . albicans suspension (10(7) cells/ml) and incubated at 37 degrees C for 90 min with bovine serum, and the percentage germ-tube-positive Candida cells was quantified using a haemocytometer, under light microscopy . In general, out of eight bacteria, Streptococcus sanguis SK21A, Streptococcus salivarius SK56, Escherichia coli ATCC 25922, and S . salivarius OBU3 suppressed germ-tube formation to varying degrees, with different C albicans isolates . Porphyromonas gingivalis Pg 50, Lactobacillus casei ATCC 7469 and Prevotella intermedia OBU4 elicited significant enhancement of germ-tube formation, whereas S . sanguis OBU 2 had no effect . E . coli ATCC 25922 was the only organism to show statistically significant suppression of germ-tube formation (p=0.0312) . A significant increase in the germ tube production of C . albicans isolated from HIV-infected compared with HIV-free individuals was also noted . The current results tend to suggest that commensal and transient oral bacterial populations may selectively influence the differential expression of germ-tube-forming ability of C . albicans isolates. APMIS, 2001 Feb, 109(2), 117 - 26 Predominant cultivable subgingival microbiota of healthy and HIV-infected ethnic Chinese; Tsang CS et al.; Although clinically distinctive types of periodontal disease are known to be associated with HIV infection, the pathogenesis remains unclear . In the present study, the subgingival microflora of 21 HIV-infected and 11 HIV-free ethnic Chinese were studied using the direct microscopic and anaerobic culture methods . Motile curved rods were found to be three times higher in the HIV-infected group under direct microscopy . Otherwise, there were no significant differences between the diseased and healthy groups when analyzed either in relation to the morphotype distribution or Gram stain morphology or oxygen tolerance . The most common bacteria isolated were Capnocytophaga species followed by Prevotella loescheii, Streptococcus sanguinis, Lactobacillus spp . and Fusobacterium spp . Although there were 20 bacterial species that were strictly limited to the HIV-infected group, and 5 limited to the healthy group, none of the species was a predominant isolate in either group (p>0.05) . These findings agree with previous studies which report that subgingival bacteria of HIV-infected individuals (with or without periodontal disease) are similar to those found in healthy HIV-free individuals (with or without periodontal disease) . Further work examining the subgingival microflora from patients with specific and/or severe forms of HIV-associated periodontal disease is required to shed light on the pathogenesis of this complex clinical entity. Enzyme Microb Technol, 2001 Jun 7, 28(9-10), 827 - 834 Batch cultures of supplemented whey permeate using Lactobacillus helveticus: unstructured model for biomass formation, substrate consumption and lactic acid production; Amrane A; The Luedeking and Piret expression can not account for the cessation of production observed at the end of batch; so an empiric term has been previously added to this equation which accounted in a global way for possible substrate limitations . In the model developed in this work, a carbon substrate limitation appeared explicitly in the production expression . Assuming a sigmoidal variation with time of specific growth rate previously validated, the new production model matched well the entire experimental production kinetics . It has been successfully tested for a wide range of nitrogen supplementations, i.e . from an almost total coupling between growth and production for largely supplemented media, to a high decoupling in case of few available nitrogen . Since all the parameters of this model have an obvious biologic meaning, it may be an unvaluable tool for the comprehension of the phenomenon . The model accounted also well for the variation of the specific production rate versus specific growth rate, avoiding the noise due to the direct differentiation of experimental data. Int J Food Microbiol, 2001 May 10, 65(3), 213 - 8 Characteristics and significance of yeasts' involvement in cassava fermentation for 'fufu' production; Oyewole OB; Six different strains of yeast, namely Candida krusei, C . tropicalis, Pichia saitoi, Saccharomyces cerevisiae, P . anomala and Zygosaccharomyces bailii were found present in cassava-fermenting water in the early part of the fermentation . The latter part of the fermentation was dominated in all cases by three strains of yeast namely C . krusei, C . tropicalis and Z . bailii . All the yeast strains exhibited amylolytic capabilities while none was able to produce cellulase . All the strains except Zygosaccharomyces spp . exhibited polygalacturonase activity, but only C . krusei was able to produce linamarase . In a study on the inter-relationships between C . krusei and Lactobacillus plantarum, the growth of the yeast strain was not enhanced in cassava by the presence of the lactic acid bacteria, but the growth of the L . plantarum strain was significantly enhanced when co-inoculated with C . krusei. Int J Food Microbiol, 2001 May 10, 65(3), 149 - 62 AT oligonucleotides inducing B lymphocyte activation exist in probiotic Lactobacillus gasseri; Kitazawa H et al.; This study determined oligonucleotide sequences of mitogenic DNA derived from lactic acid bacteria (LAB) . The chromosomal DNA, which was purified from 12 out of 16 strains of Lactobacillus acidophilus group LAB, induced proliferation of splenic lymphocytes . When DNA from L . gasseri JCM1131T was cloned and amplified using PCR, the mitogenic activities of B lymphocytes were significantly increased by 108 of 321 DNA clones . Ten high homologous nucleotide sequences were found as possible DNA sequences of mitogens, and were then chemically synthesized (sOL-LG1 to sOL-LG10) . Two nucleotide sequences (sOL-LG7 and sOL-LG10) that consist of only A and T nucleotides (AT oligonucleotides) were characterized as B lymphocyte specific mitogens because they resulted in proliferation of B lymphocytes but not of T lymphocytes . sOL-LG7 preferentially bound to large B lymphocytes and enhanced the expression of the CD86 antigen more than the CD69 antigen on B lymphocytes . The findings show that mitogenic AT oligonucleotides are likely to restrict pre-activated subsets of B lymphocytes . This study demonstrated that novel AT oligonucleotides triggering B lymphocyte mitogenic responses exist in the nucleoids of L . gasseri and proposed that they have potential as applicants for the production of new functional foods, "Bio-Defense Foods". Antonie Van Leeuwenhoek, 2001 Jan, 79(1), 73 - 9 Changes in fatty acid composition and degree of unsaturation of (brady)rhizobia as a response to phases of growth, reduced water activities and mild desiccation; Boumahdi M et al.; The effects of growth phase, reductions in the water activity (a(w)) of the growth medium and mild desiccation on the composition and the degree of unsaturation of cellular fatty acids (CFA) of Sinorhizobium meliloti, Bradyrhizobium elkanii and Bradyrhizobium japonicum were studied . During the course of growth, an interchange of cis-vaccenic with lactobacillic acid and a slight increase in palmitic acid were observed while other fatty acids remained constant . The degree of unsaturation was significantly higher in the exponential phase of growth . Reductions in the a(w) of the medium led to an increase in lag phase, a reduction in growth rate and maximal optical densities (OD) in stationary phase cells . A decrease in the degree of unsaturation of CFA was also observed as the a(w) was reduced from 0.999 to 0.969 and after desiccation to 83.5% relative humidity (R.H.) . The changes in the degree of unsaturation of CFA observed after growth at reduced a(w) may be one of the pre-adaptation steps to endure more severe desiccation. Antonie Van Leeuwenhoek, 2001 Jan, 79(1), 1 - 6 Randomly amplified polymorphic DNA (RAPD) profiles for the distinction of Lactobacillus species; Nigatu A et al.; Forty-one type and reference strains of Lactobacillus were evaluated using their randomly amplified polymorphic DNA band profiles . Developed bands for each strain were distinct and enabled discrimination . The best correlations were obtained applying the Pearson product moment correlation coefficient (r) together with the unweighted pair group method using arithmetic averages algorithm . All of the strains were clearly differentiated at and below the 72% similarity value . Species discrimination might be possible making use of the distinctly polymorphic bands amplified specific to a strain. BMJ . 2001 Jun 2;322(7298):1327. Effect of long term consumption of probiotic milk on infections in children attending day care centres: double blind, randomised trial; Hatakka K et al.; OBJECTIVE: To examine whether long term consumption of a probiotic milk could reduce gastrointestinal and respiratory infections in children in day care centres . DESIGN: Randomised, double blind, placebo controlled study over seven months . SETTING: 18 day care centres in Helsinki, Finland . PARTICIPANTS: 571 healthy children aged 1-6 years: 282 (mean (SD) age 4.6 (1.5) years) in the intervention group and 289 (mean (SD) age 4.4 (1.5) years) in the control group . Intervention: Milk with or without Lactobacillus GG . Average daily consumption of milk in both groups was 260 ml . MAIN OUTCOME MEASURES: Number of days with respiratory and gastrointestinal symptoms, absences from day care because of illness, respiratory tract infections diagnosed by a doctor, and course of antibiotics . RESULTS: Children in the Lactobacillus group had fewer days of absence from day care because of illness (4.9 (95% confidence interval 4.4 to 5.5) v 5.8 (5.3 to 6.4) days, 16% difference, P=0.03; age adjusted 5.1 (4.6 to 5.6) v 5.7 (5.2 to 6.3) days, 11% difference, P=0.09) . There was also a relative reduction of 17% in the number of children suffering from respiratory infections with complications and lower respiratory tract infections (unadjusted absolute % reduction -8.6 (-17.2 to -0.1), P=0.05; age adjusted odds ratio 0.75 (0.52 to 1.09), P=0.13) and a 19% relative reduction in antibiotic treatments for respiratory infection (unadjusted absolute % reduction -9.6 (-18.2 to -1.0), P=0.03; adjusted odds ratio 0.72 (0.50 to 1.03), P=0.08) in the Lactobacillus group . CONCLUSIONS: Lactobacillus GG may reduce respiratory infections and their severity among children in day care . The effects of the probiotic Lactobacillus GG were modest but consistently in the same direction. Microbiol Immunol, 2001, 45(4), 271 - 5 Characterization of the Lactobacillus casei group and the Lactobacillus acidophilus group by automated ribotyping; Ryu CS et al.; A total of 91 type and reference strains of the Lactobacillus casei group and the L acidophilus group were characterized by the automated ribotyping device Riboprinter microbial characterization system . The L . casei group was divided into five (C1-C5) genotypes by ribotyping . Among them, the strain of L . casei ATCC 334 was clustered to the same genotype group as most of L . paracasei strains and L casei JCM 1134T generated a riboprint pattern that was different from the type strain of L . zeae . These results supported the designation of L . casei ATCC 334 as the neotype strain, but were not consistent with the reclassification of L . casei JCM 1134T as L . zeae . The L . acidophilus group was also divided into 14 (A1-A11, B1-B3) genotypes by ribotyping . L . acidophilus, L . amylovorus, L . crispatus and L . gallinarum generated ribotype patterns that were distinct from the patterns produced by L . gasseri and L . johnsonii . This result confirmed previous data that the L . acidophilus group divided to two major clusters . Five strains of L . acidophilus and two strains of L . gasseri were correctly reidentified by ribotyping . Most strains belonging to the L . casei group and the L . acidophilus group were discriminated at the species level by automated ribotyping . Thus this RiboPrinter system yields rapid, accurate and reproducible genetic information for the identification of many strains. J Dairy Sci, 2001 May, 84(5), 1149 - 55 The effect of Lactobacillus buchneri and other additives on the fermentation and aerobic stability of barley silage; Kung L Jr et al.; Whole-plant barley (39.4% dry matter) was treated with various chemical and biological additives to assess their effects on silage fermentation and aerobic stability . Treatments were untreated forage, forage treated with several amounts of Lactobacillus buchneri and enzymes (L . buchneri at 1 x 10(5), 5 x 10(5), and 1 x 10(6) cfu/g of fresh forage), forage treated with an inoculant containing (Lactobacillus plantarum, Pediococcus pentosaceus, Propionibacterium freudenreichii, and enzymes), or forage treated with a buffered propionic acid-based additive (0.2% of fresh weight) . Sixty-nine d after ensiling, silages treated with L . buchneri and enzymes had lower pH, but had higher concentrations of acetic and propionic acids and higher concentrations of ethanol when compared with untreated silage . Silage treated with the multistrain inoculant containing L . plantarum had lower pH and higher concentrations of lactic acid, but lower concentrations of ammonia-N, neutral detergent fiber, and acid detergent fiber than did untreated silage . The addition of the buffered propionic acid additive resulted in silage with higher concentrations of lactic and acetic acid compared with untreated silage . Numbers of yeasts in all silages were low at silo opening (less than 3.0 log cfu/g) and were numerically the lowest in silages treated with L . buchneri but only treatment with the intermediate and high level of L . buchneri improved the aerobic stability of silage . Because of the altered fermentation pattern, inoculation with L . buchneri, when applied at equal to or more than 5 x 10(5) cfu/g, and enzymes improved the aerobic stability of barley silage. J Dairy Sci, 2001 May, 84(5), 1011 - 9 Tyrosine and phenylalanine catabolism by Lactobacillus cheese flavor adjuncts; Gummalla S et al.; Bacterial metabolism of Tyr and Phe has been associated with the formation of aromatic compounds that impart barny-utensil and floral off-flavors in cheese . In an effort to identify possible mechanisms for the origin of these compounds in Cheddar cheese, we investigated Tyr and Phe catabolism by Lactobacillus casei and Lactobacillus helveticus cheese flavor adjuncts under simulated Cheddar cheese-ripening (pH 5.2, 4% NaCl, 15 degrees C, no sugar) conditions . Enzyme assays of cell-free extracts indicated that L . casei strains catabolize Tyr and Phe by successive, constitutively expressed transamination and dehydrogenation reactions . Similar results were obtained with L . helveticus strains, except that the dehydrogenase enzymes were induced during incubation under cheese-ripening conditions . Micellar electrokinetic capillary chromatography of supernatants from L . casei and L . helveticus strains incubated under simulated cheese-ripening conditions confirmed that Tyr and Phe transamination and dehydrogenation pathways were active in both species and also showed these reactions were reversible . Major products of Tyr catabolism were phydroxy phenyl lactic acid and p-hydroxy phenyl acetic acid, while Phe degradation gave rise to phenyl lactic acid, phenyl acetic acid, and benzoic acid . However, some of these products were likely formed by nonenzymatic processes, since spontaneous chemical degradation of the Tyr intermediate p-hydroxy phenyl pyruvic acid produced p-hydroxy phenyl acetic acid, p-hydroxy phenyl propionic acid, and p-hydroxy benzaldehyde, while chemical degradation of the Phe intermediate phenyl pyruvic acid gave rise to phenyl acetic acid, benzoic acid, phenethanol, phenyl propionic acid, and benzaldehyde. Ned Tijdschr Tandheelkd, 2000 Oct, 107(10), 402 - 5 {Root caries in patients in periodontal follow-up care . Prevalence and risk factors}; Reiker J et al.; The aim of this cross-sectional study was to investigate the prevalence and several risk indicators of root caries in 45 periodontal maintenance patients, who had been actively treated for adult periodontitis 11-22 years ago . These patients were part of a routine 3-6 monthly maintenance schedule . Active and inactive root caries and root fillings were recorded, as well as coronal caries experience . Plaque and bleeding scores, number of exposed root surfaces, rate of saliva secretion, saliva buffer capacity, S . mutans counts and Lactobacilli were also scored . From the total of 45 subjects, 37 patients (82%) showed root lesions (root caries and/or fillings), while only 8 patients were free of any root lesions . On average, there were 4.3 lesions per patient (range 0-19) in the present study . Of all damaged root surfaces, 9% were active lesions, mostly located on mandibular teeth at lingual and vestibular sites; 40% were inactive lesions often detected at vestibular sites . The remaining damaged root surfaces (51%) were restored; they were equally divided over both jaws . A higher number of root lesions was observed in those patients with > 106 S . mutans/ml saliva . Although the actual number of lesions per patient was low in relation to the large number of sites with gingival recession, the results from this cross-sectional study in periodontal maintenance patients indicate that: root caries can be regarded as a complication in periodontal maintenance patients, that the individual number of root lesions correlate with individual dental plaque score, that a high number of root lesions is associated with counts of salivary S . mutans, and that no relation between root caries and coronal caries experience, salivary secretion rate or salivary buffering capacity seems present . Therefore, repeated oral hygiene instructions and adjunctive preventive measures including diet counseling and fluoride rinses, as well as fluoride and chlorhexidine varnishes, should be advocated in high-risk patients. Nahrung, 2001 Apr, 45(2), 118 - 24 Optimum production, stability, partial purification and inhibitory spectrum of antimicrobial compounds produced by Pediococcus pentosaceus DI; el-Adawy TA; The optimum conditions for production of antimicrobial compounds by Pediococcus pentosaceus DI were studied . The antimicrobial compounds in cell free fermented medium were extracted (methanol-acetone), then tested for inhibitory activity against fourteen bacterial strains and its stability to heating, various pH and proteolytic enzymes . In addition, methanol-acetone extract was partial purified through Sephadex G-100 column and thin-layer chromatography . Production of antimicrobial compounds were maximized when P . pentosaceus DI was grown in lactobacilli MRS containing 0.05% L-cysteine-HCl medium at 30 degrees C for 48 h . The methanol-acetone extract showed relatively broad antimicrobial spectrum including lactic acid bacteria and some spoilage and pathogenic bacteria . Antimicrobial activity of methanol-acetone extract was retained after heating (100 degrees C for 30 min) at pH 2.5 to 6.0 but was lost after treating with several proteolytic enzymes at pH 6.5 and 7.0 . Sephadex G-100 column revealed three peaks in methanol-acetone extract . The major peak was eluted at 40 ml and including three fractions, which exhibited inhibitory activity, while the other peaks were principally free from any antimicrobial compounds . Thin-layer chromatography of crude methanol-acetone extract and the three fractions, which exhibited inhibitory activity, showed that there was one main spot with Rf at 0.8. Curr Microbiol, 2001 Jul, 43(1), 38 - 42 The effects of dietary ferric iron and iron deprivation on the bacterial composition of the mouse intestine; Tompkins GR et al.; The influence of dietary ferric iron on the intestinal microbiota of mice was investigated with a view to promoting benign lactic acid bacteria (which have minimal iron requirements) in order to enhance colonization-resistance potential . Three groups of eight mice received a diet differing only in iron content, for a period of 12 weeks . Dietary iron deprivation resulted in overall increased small intestinal bacterial populations, including lactic acid bacteria, but these differences were generally not significant (p > 0.05) . With the exception of coliforms, all examined bacterial groups (anaerobes, micro-aerophiles, lactobacilli, and enterococci) were significantly (p < 0.05) elevated in the colons of iron-deprived mice . The relatively low numbers of total anaerobes in the colons of iron-replete and iron-overloaded mice suggested that, as well as promotion of bacteria under iron-deprived condition, provision of ferric iron suppressed bacteria, probably by oxidation of normally reduced environments. Curr Microbiol, 2001 Jul, 43(1), 17 - 20 Sequence analyses of a broad host-range plasmid containing ermT from a tylosin-resistant Lactobacillus sp . Isolated from swine feces; Whitehead TR et al.; Anaerobic bacteria resistant to the macrolide antibiotics tylosin and erythromycin were isolated from the feces of swine . One of the strains, 121B, was initially identified by 16S rDNA sequence analysis as an unknown Lactobacillus sp . The strain was found to contain at least two plasmids, one of which was capable of replicating and providing erythromycin and tylosin resistance to Bacillus subtilis, Streptococcus gordonii, and Escherichia coli . DNA sequence analyses of the 4,232-bp plasmid, p121BS, identified one open reading frame encoding a methylase gene highly similar (> 98% amino acid identity, > 99% DNA sequence identity) to the ermT gene from the Lactobacillus reuteri plasmid pGT633 . This is only the second ermT gene to be reported . p121BS also contains two additional open reading frames with significant amino acid similarities to replication proteins from Lactobacillus and other Gram-positive bacteria. Appl Environ Microbiol, 2001 Jun, 67(6), 2699 - 704 Strategy for manipulation of cheese flora using combinations of lacticin 3147-producing and -resistant cultures; Ryan MP et al.; The aim of the present study was to develop adjunct strains which can grow in the presence of bacteriocin produced by lacticin 3147-producing starters in fermented products such as cheese . A Lactobacillus paracasei subsp . paracasei strain (DPC5336) was isolated from a well-flavored, commercial cheddar cheese and exposed to increasing concentrations (up to 4,100 arbitrary units {AU}/ml) of lantibiotic lacticin 3147 . This approach generated a stable, more-resistant variant of the isolate (DPC5337), which was 32 times less sensitive to lacticin 3147 than DPC5336 . The performance of DPC5336 was compared to that of DPC5337 as adjunct cultures in two separate trials using either Lactococcus lactis DPC3147 (a natural producer) or L . lactis DPC4275 (a lacticin 3147-producing transconjugant) as the starter . These lacticin 3147-producing starters were previously shown to control adventitious nonstarter lactic acid bacteria in cheddar cheese . Lacticin 3147 was produced and remained stable during ripening, with levels of either 1,280 or 640 AU/g detected after 6 months of ripening . The more-resistant adjunct culture survived and grew in the presence of the bacteriocin in each trial, reaching levels of 10(7) CFU/g during ripening, in contrast to the sensitive strain, which was present at levels 100- to 1,000-fold lower . Furthermore, randomly amplified polymorphic DNA-PCR was employed to demonstrate that the resistant adjunct strain comprised the dominant microflora in the test cheeses during ripening. Poult Sci, 2001 May, 80(5), 562 - 71 Effects of hen age, Bio-Mos, and Flavomycin on poult susceptibility to oral Escherichia coli challenge; Fairchild AS et al.; The effects of hen age, Escherichia coli, and dietary Bio-Mos and Flavomycin on poult performance from 1 to 21 d were studied . Day-of-hatch BUTA (BIG-6) male poults were gavaged orally (1 mL) with approximately 10(8) cfu/mL E . coli composed of four serotypes or sterile carrier broth . A mixture of the same E . coli cultures was added to the poults' water troughs to attain a concentration of approximately 10(6) cfu/mL on a weekly basis to ensure a continuous bacterial challenge . Within each E . coli split plot treatment group, poults from hens of different ages (33 and 58 wk of age) were fed diets containing Bio-Mos (1 g/kg feed), Flavomycin (2.2 mg active ingredient/kg feed), Bio-Mos plus Flavomycin, or a control diet, in a randomized complete block design . This experiment yielded eight treatments per challenge group . At Weeks 1 and 3, eight birds from each treatment from the E . coli challenged and unchallenged groups were randomly chosen for bacterial sampling of liver and intestinal tissue for coliforms, aerobic bacteria, and Lactobacillus spp . E . coli isolates from tissue samples were O serotyped . During E . coli challenge, dietary Bio-Mos and Flavomycin improved poult BW and BW gains (P < or = 0.05) . When poults were not challenged with E . coli, poults from old hens had improved BW and cumulative BW gains over poults from young hens (P < or = 0.05) . Cumulative 3-wk BW gains for unchallenged poults from young hens were improved by Bio-Mos and Flavomycin (P < or = 0.05) alone and in combination when compared to the control diet . Two of the four E . coli serotypes administered were recovered . Several serotypes were recovered that were not administered . It may be concluded that dietary Bio-Mos and Flavomycin can improve the overall performance of poults, especially when they are faced with an E . coli challenge. Biochemistry, 2001 May 29, 40(21), 6199 - 204 Active site residues of glutamate racemase; Glavas S et al.; Glutamate racemase, MurI, catalyzes the interconversion of glutamate enantiomers in a cofactor-independent fashion and provides bacteria with a source of D-Glu for use in peptidoglycan biosynthesis . The enzyme uses a "two-base" mechanism involving a deprotonation of the substrate at the alpha-position to form an anionic intermediate, followed by a reprotonation in the opposite stereochemical sense . In the Lactobacillus fermenti enzyme, Cys73 is responsible for the deprotonation of D-glutamate, and Cys184 is responsible for the deprotonation of L-glutamate; however, very little is known about the roles of other active site residues . This work describes the preparation of four mutants in which strictly conserved residues containing ionizable side chains were modified (D10N, D36N, E152Q, and H186N) . During the course of this research, the structural analysis of a crystallized glutamate racemase indicated that three of these residues (D10, E152, and H186) are in the active site of the enzyme {Hwang, K . Y., Cho, C.-S., Kim, S . S., Sung, H.-C., Yu, Y . G., and Cho, Y . (1999) Nat . Struct . Biol . 6, 422-426} . Two of the mutants, D10N and H186N, displayed a marked decrease in the values of k(cat), but not K(M), and are therefore implicated as important catalytic residues . Further analysis of the primary kinetic isotope effects observed with alpha-deuterated substrates showed that a significant asymmetry was introduced into the free energy profile by these two mutations . This is interpreted as evidence that the mutated residues normally assist the catalytic thiols in acting as bases (D10 with C73 and H186 with C184) . An alternate possibility is that the residues may serve to stabilize the carbanionic intermediate in the racemization reaction. Mol Genet Genomics, 2001 Mar, 265(1), 198 - 206 Regulation of bacteriocin production in Lactobacillus plantarum depends on a conserved promoter arrangement with consensus binding sequence; Risoen PA et al.; Bacteriocin production in Lactobacillus plantarum C11 is regulated by a three-component signal transduction system comprising a peptide pheromone (PlnA), a histidine protein kinase (PlnB), and two homologous response regulators (RRs; PlnC and PlnD) . Both RRs are DNA-binding proteins that bind to promoter-proximal elements in the pln regulon . The binding site for the two regulators consists of two 9-bp direct repeats, that conform to the consensus sequence 5'-TACGTTAAT-3', and the repeats are separated by an intervening 12-bp AT-rich spacer region . In the present work, the plhA promoter was used as a model to evaluate the significance of the binding sequence and conserved promoter arrangement . Point substitutions in the consensus sequence, particularly those in invariant positions, either abolished or significantly reduced binding of PlnC and PlnD . Both regulators bind as homodimers to DNA fragments containing a complete set of regulatory elements, while removal of either repeat, or alterations in the length of the spacer region, significantly weakened binding of both protein dimers . DNase I footprinting demonstrated that PlnC and PlnD both bind to, and protect, the direct repeats . By fusing the plnA promoter region to the beta-glucuronidase (GUS) gene, it was shown that promoter activity is dependent on an intact set of accurately organized repeats . The in vitro and in vivo results presented here confirm the involvement of the repeats as regulatory elements in the regulation of bacteriocin production. Acta Odontol Scand, 2001 Apr, 59(2), 88 - 92 Effect of a school-based preventive program with salivary lactobacillus counts as sugar-motivating tool on caries increment in adolescents; Nylander A et al.; The caries preventive outcome of a school-based program with salivary; lactobacillus counts as sugar-motivating tool was evaluated in six cohorts of totally 936 adolescents in a comprehensive school in Sweden . Students from a neighboring district with similar socioeconomic structure but with no corresponding dental health-promoting activities were selected as reference . The program started in the beginning of the 7th grade (13 years) and was terminated at the end of the 9th grade (16 years) . Salivary lactobacilli were evaluated semi-annually with a dip-slide method and used for individual counseling . Dental caries was scored from the dental records and bitewing radiographs of each 4th participant at baseline and at 16 and 19 years of age . The number of salivary lactobacilli decreased significantly (P< 0.05) in all cohorts but one during the program . There was no significant difference in the increment of caries (DFS) between the participants from the study and reference schools, either at the end of the program or at 19 years of age . The increment of proximal enamel caries was slightly lower in the study group compared with the reference group (P< 0.05) at the final registration . Considering the time and efforts spent, the results did not seem to justify a school-based intervention with lactobacillus counts as a sugar-motivating tool in an adolescent low-caries population. Cytobios, 2001, 105(408), 35 - 43 Bacterial vaginosis among a group of married Jordanian women: occurrence and laboratory diagnosis; Abu Shaqra QM; A total of 310 vaginal swabs collected from a group of married Jordanian women complaining of vaginal discharge were examined for bacterial vaginosis . The scoring system of Nugent for the interpretation of Gram staining was employed . This system revealed the presence of the condition in 29.7% of patients . Results obtained using the scoring system correlated significantly with the detection of clue cells and the scarcity of white blood cells in the vaginal discharge . An inverse relationship was found between bacterial vaginosis and Lactobacillus morphotypes determined by Gram staining . No definite relationship was detected between bacterial vaginosis and the recovery of Gardnerella vaginalis by culture as this organism was isolated from swabs which according to the Nugent criterion were negative for bacterial vaginosis . Bacterial vaginosis among the women investigated was more prevalent than vaginitis caused by Trichomonas vaginalis or yeasts. Infect Dis Obstet Gynecol, 2001, 9(1), 41 - 5 Effect of metronidazole on the growth of vaginal lactobacilli in vitro; Simoes JA et al.; OBJECTIVE: To determine whether metronidazole has an adverse effect on the growth of Lactobacillus . METHODS: Hydrogen peroxide- and bacteriocin-producing strains of Lactobacillus were used as test strains . Concentrations of metronidazole used ranged from 128 to 7000 microg/ml . Susceptibility to metronidazole was conducted by the broth microdilution method recommended by the National Committee for Clinical Laboratory Standards . RESULTS: Growth of Lactobacillus was partially inhibited at concentrations between 1000 and 4000 microg/ml (p = 0.014) . Concentrations > or = 5000 microg/ml completely inhibited growth of Lactobacillus . Concentrations between 128 and 256 microg/ml stimulated growth of Lactobacillus (p = 0.025 and 0.005, respectively) . Concentrations of metronidazole between 64 and 128 microg/ml or > or = 512 microg/ml did not have an inhibitory or a stimulatory effect on the growth of Lactobacillus compared to the control . CONCLUSIONS: High concentration of metronidazole, i.e . between 1000 and 4000 microg/ml, partially inhibited the growth of Lactobacillus . Concentrations > or = 5000 microg/ml completely suppressed the growth of Lactobacillus . Concentrations between > or = 128 and < or = 256 microg/ml stimulated the growth of Lactobacillus . Further investigation to determine the ideal concentration of metronidazole is needed in order to use the antimicrobial agent effectively in the treatment of bacterial vaginosis. Infect Dis Obstet Gynecol, 2001, 9(1), 33 - 9 Antimicrobial protein produced by vaginal Lactobacillus acidophilus that inhibits Gardnerella vaginalis; Aroutcheva AA et al.; OBJECTIVE: To isolate bacteriocin from a vaginal strain of Lactobacillus acidophilus . METHODS: L . acidophilus 160 was grown on two media . The first was MRS broth for 18 hours; the cells were harvested, washed, and placed into a chemically defined medium . The second medium resembled vaginal fluid minus protein . Bacteriocin was precipitated from both media using ammonium sulfate . The growth-inhibiting activity of bacteriocin was determined by a bioassay using nine different isolates of Gardnerella vaginalis . RESULTS: MRS broth is not a suitable medium for extracting bacteriocin, because it binds with Tween 80 . Bacteriocin was isolated, without contaminating constituents, from chemically defined medium and identified as a single band by electrophoresis . Bacteriocin has a molecular weight of 3.8 kDa . All nine isolates of Gardnerella were inhibited by the bacteriocin isolated from L . acidophilus 160 . CONCLUSIONS: Bacteriocin produced by L . acidophilus 160 was isolated from the chemically defined medium (starvation medium) in a partially pure form . L . acidophilus 160 bacteriocin inhibited growth of all nine isolates of Gardnerella vaginalis. Arch Biochem Biophys, 2001 Apr 15, 388(2), 179 - 84 Effect of lipid composition on the stability of cellular membranes during freeze-thawing of Lactobacillus acidophilus grown at different temperatures; Fernandez Murga ML et al.; Lactobacillus acidophilus CRL 640 grown at the optimal temperature of 37 degrees C (M37) appeared more sensitive to freeze-thawing than when it was grown at 25 degrees C (M25) . In the first case, 87% of the cells died, in contrast to 33% for cells grown at 25 degrees C . All the surviving M37 cells showed sensitivity to NaCl . However, among the surviving M25 cells, only 85% were sensitive to NaCl . The rest of the cells were considered uninjured . Freeze-thawing in cells grown at 25 degrees C showed a liberation of nucleic acids and proteins . However, the leakage was higher in M37 cells after freeze-thawing . The greater fraction of damaged cells were observed in M25 culture after freeze-thawing . A relative increase of 81% in cardiolipid (CL), with respect to total phospholipids and 72% triglycosyldiglyceride (TGDG) with respect to the total glycolipids was observed in M37 . In addition, a decrease of palmitoyl (C16:0), oleoyl (C18:0) fatty acids at CL, phosphatidylglycerol (PG), and diglicosyldiglyceride (DGDG) fractions and the increase of C19 cyc and C18:0, 10-OH fatty acids in neutral lipid, and CL fractions was also apparent . In M25 cells, the concentration of DGDG and PG was higher than in M37 cells . The difference in cryotolerance between the frozen cultures emphasizes the importance of selecting appropriate conditions of growth of microorganisms for use as dietary adjuncts. AIDS Alert, 1998 Jul, 13(7), 79 - 81 Does loss of vaginal flora increase risk of STD? Microflora in oral ecosystems in primary Sjögren's syndrome. Department of Oral Microbiology, Department of Rheumatology, Goteborg University, Sweden . Annica.Almstahl@odontologi.gu.se OBJECTIVE: Knowledge of the effect of primary Sjogren's syndrome (pSS) on the microbial flora in the different predilection sites for oral disorders is needed for planning preventive treatment . We carried out microbial analysis of samples from the dorsum of the tongue, smooth mucosa, supragingival tooth surfaces, and the gingival crevice region of 20 patients with pSS . METHODS: A clinical oral examination was performed and whole unstimulated and stimulated secretion rates were measured . RESULTS: Compared with healthy controls, subjects with pSS harbored higher numbers and frequencies of Streptococcus mutans, Lactobacillus spp., and Candida albicans in the supragingival plaque . On the smooth mucosa and tongue, the pSS subjects displayed an increased frequency of C . albicans, Staphylococcus aureus, enterics, and enterococci . C . albicans was detected about twice as frequently in the supragingival plaque as it was on the tongue . In the gingival crevice region, the pSS group harbored slightly lower proportions of Fusobacterium nucleatum and Prevotella intermedia/Prevotella nigrescens than controls . The clinical and microbial differences were mainly due to the pSS subjects with a stimulated secretion rate of < 0.5 ml/min . Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans were not detected in any subject with pSS . CONCLUSION: The microbial flora in the different ecosystems reflected the status of oral disorders in the subjects with pSS . Specific site sampling and analysis in subjects with pSS revealed further differences compared with controls, and is therefore preferable to saliva sampling for oral treatment planning and for the evaluation of the effect of oral treatment and of preventive measures implemented in individuals with pSS. Int Immunopharmacol, 2001 Feb, 1(2), 211 - 8 Suppression of T-cell activation by Lactobacillus rhamnosus GG-degraded bovine casein; Pessi T et al.; Earlier data indicate that Lactobacillus rhomnosus GG ATCC 53103 (L . GG), a commensal intestinal bacterial strain, promotes the degradation of proteins in the gut in vivo, and bovine casein hydrolysed with L . GG-derived proteases suppresses lymphocyte proliferation in vitro . The present study aimed to evaluate the effect of L . GG-degraded bovine casein on T-cell activation, i.e . IL-2 mRNA expression and protein kinase C (PKC) translocation . To this end, Northern blot analyses for IL-2 mRNA expression and PKC assays with and without L . GG-degraded casein were carried out on T cells isolated from 11 healthy adults . Cell cultures in 8-11 experiments contained 1 mg ml(-1) bovine casein in degraded or undegraded form in the presence of a mitogen, i.e . phorbol 12,13-dibutyrate plus calcium ionophore (PBDu + A23187) or anti-CD3 . Also IL-2, IL-4 and IFN-gamma syntheses were determined in 24-h culture supernatants . IL-2 mRNA expression was reduced in experiments with L . GG-degraded casein . In parallel, the IL-2 concentration in PBDu + A23187-stimulated culture supernatants, expressed as geometric means (95% confidence interval), decreased from 15,892 (7174-35,203) pg ml(-1) to 4744 (2095-10,742) pg ml(-1) when containing L . GG-degraded casein . L . GG-degraded casein inhibited PKC translocation, the action resembling that of PKC inhibitor, RO31-8220 . These results extend previous data on L . GG-degraded casein, showing in vitro the suppression of T-cell activation. Fam Pract, 2001 Jun, 18(3), 253 - 7 The effect of introduction of a guideline on the management of vaginal discharge and in particular bacterial vaginosis in primary care; Langsford MJ et al.; BACKGROUND: Bacterial vaginosis (BV) is the commonest cause of vaginal discharge, and its association with obstetric and gynaecological complications is being recognized increasingly . It was our impression that BV was poorly understood and underdiagnosed in family practice . OBJECTIVE: The aim of this study was to explore the management of patients with vaginal symptoms by family practitioners and to see if the management changed after the assimilation of best practice guidelines . METHOD: Family practitioners were invited to complete a baseline questionnaire of their perceived practice, and to record actual practice when consulted about vaginal symptoms, for a minimum of 4 weeks . Consensus best practice guidelines were then provided and practice recorded for a similar period . RESULTS: Baseline data was received from 34 practitioners and suggested that the symptoms and signs of different vaginal infections were not well known . Most symptomatic patients were only investigated at re-presentation with unresolved symptoms or at recurrence, and 43% of respondents treated with empirical antifungals as a first line approach . Pregnant patients were only occasionally asked about symptoms and only occasionally examined if symptomatic . Pre-guideline practice data from 30 practitioners showed 1.2 patient consultations/week, of which 60% were examined and 55% had a high vaginal swab (HVS) sent . Only 2% had near-patient tests done . Post-guideline data from 23 family practitioners showed a lower recorded consultation rate at 0.7/week, but 90% of these were examined, 77% had an HVS sent and 69% had near-patient tests done . Of the 36 HVS examined by Gram stain, 19 (53%) showed Lactobacillus predominant flora and 10 (28%) suggested BV . Seven (19%) were borderline or ungradable . Only three (8%) showed yeasts, one of which also showed BV . CONCLUSIONS: Baseline data supported our impression that BV was under-recognized . Guidelines appeared to improve the rate of investigation of women consulting with vaginal symptoms. Antimicrob Agents Chemother, 2001 Jun, 45(6), 1751 - 60 Antimicrobial activity of intraurethrally administered probiotic Lactobacillus casei in a murine model of Escherichia coli urinary tract infection; Asahara T et al.; The antimicrobial activity of the intraurethrally administered probiotic Lactobacillus casei strain Shirota against Escherichia coli in a murine urinary tract infection (UTI) model was examined . UTI was induced by intraurethral administration of Escherichia coli strain HU-1 (a clinical isolate from a UTI patient, positive for type 1 and P fimbriae), at a dose of 1 x 10(6) to 2 x 10(6) CFU in 20 microl of saline, into a C3H/HeN mouse bladder which had been traumatized with 0.1 N HCl followed immediately by neutralization with 0.1 N NaOH 24 h before the challenge infection . Chronic infection with the pathogen at 10(6) CFU in the urinary tract (bladder and kidneys) was maintained for more than 3 weeks after the challenge, and the number of polymorphonuclear leukocytes and myeloperoxidase activity in the urine were markedly elevated during the infection period . A single administration of L . casei Shirota at a dose of 10(8) CFU 24 h before the challenge infection dramatically inhibited E . coli growth and inflammatory responses in the urinary tract . Multiple daily treatments with L . casei Shirota during the postinfection period also showed antimicrobial activity in this UTI model . A heat-killed preparation of L . casei Shirota exerted significant antimicrobial effects not only with a single pretreatment (100 microg/mouse) but also with multiple daily treatments during the postinfection period . The other Lactobacillus strains tested, i.e., L . fermentum ATCC 14931(T), L . jensenii ATCC 25258(T), L . plantarum ATCC 14917(T), and L . reuteri JCM 1112(T), had no significant antimicrobial activity . Taken together, these results suggest that the probiotic L . casei strain Shirota is a potent therapeutic agent for UTI. J Oral Rehabil, 2001 Apr, 28(4), 314 - 9 Bactericidal effect of dentin primer containing antibacterial monomer methacryloyloxydodecylpyridinium bromide (MDPB) against bacteria in human carious dentin; Imazato S et al.; The aim of this study was to investigate the bactericidal effect of a dentin primer incorporating the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) against bacteria in human dentinal carious lesions . To evaluate the antibacterial activity of MDPB against anaerobes, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) against obligate anaerobes and facultative anaerobic strains of lactobacilli were determined . Bacteria were recovered from carious dentin samples obtained from the teeth of patients, and the bactericidal activities of the experimental primer containing 5% MDPB and three commercially available primers were compared by counting the number of viable cells after contact with diluted solutions of each primer for 30 s . MDPB showed strong antibacterial activity against anaerobes, the MIC and MBC values ranging from 3.9 to 31.3 micrograms/ mL-1 and 15.6-125 micrograms/ mL-1, respectively . Experimental primer containing MDPB was the most bactericidal among the materials tested (ANOVA, Fisher's PLSD test, P < 0.05) and was able to kill the bacteria completely even when diluted 40 times, while the three commercial products exhibited little activity at 40 times dilution . These results indicate that incorporation of MDPB into dentin primer could be beneficial for eliminating the residual bacteria in cavities. J Am Coll Nutr, 2001 Apr, 20(2 Suppl), 149 - 56 Systemic immunity-enhancing effects in healthy subjects following dietary consumption of the lactic acid bacterium Lactobacillus rhamnosus HN001; Sheih YH et al.; OBJECTIVE: To determine the effects of the probiotic lactic acid bacterium, Lactobacillus rhamnosus HN001, on natural cellular immunity when delivered orally in normal low-fat milk (LFM) or lactose-hydrolyzed low-fat milk (LFM-LH) . DESIGN: A three stage, pre-post intervention trial, spanning nine weeks . SETTING: Taipei Medical College Hospital, Taipei, Taiwan . SUBJECTS: Fifty-two healthy middle-aged and elderly volunteers (17 males, 35 females; median age 63.5, range 44-80) . INTERVENTIONS: Stage 1 (run-in diet): 25 g/200 mL reconstituted LFM powder, twice daily for 3 weeks . Stage 2 (probiotic intervention): LFM or LFM-LH, supplemented with 10(9) CFUs/g L . rhamnosus HN001 in each case, for 3 weeks . Stage 3 (wash-out): LFM for 3 weeks . MEASURES OF OUTCOME: In vitro phagocytic capacity of peripheral blood polymorphonuclear (PMN) leukocytes; in vitro tumoricidal activity of natural killer (NK) leukocytes . RESULTS: Immunological responses were unaffected by the run-in diet of LFM alone . In contrast, the relative proportion of PMN cells showing phagocytic activity increased by 19% and 15%, respectively, following consumption of HN001 in either LFM or LFM-LH; the relative level of NK cell tumor killing activity increased by 71% and 147% . In most cases these levels declined following cessation, but remained above baseline . CONCLUSIONS: Dietary consumption of L . rhamnosus HN001, in a base of low-fat milk or lactose-hydrolyzed low-fat milk, appears to enhance systemic cellular immune responses and may be useful as a dietary supplement to boost natural immunity. J Appl Microbiol, 2001 May, 90(5), 819 - 28 Effect of lactobacilli on yeast growth, viability and batch and semi-continuous alcoholic fermentation of corn mash; Thomas KC et al.; AIMS: The aim of this study was to evaluate interactions between Saccharomyces cerevisiae and selected strains of lactobacilli regarding cell viabilities, and production of organic acids and ethanol during fermentation . METHODS AND RESULTS: Corn mashes were inoculated with yeasts and selected strains of lactobacilli, and fermented in batch or semi-continuous (cascade) mode . Eth