Lactobacillus

Schweiz Monatsschr Zahnmed, 1991, 101(8), 993 - 6
{The determination of caries risk in schoolchildren based on microbiological-chemical analyses of the saliva and on the clinical dental status}; Brandle CR et al.; In a feasibility study for the determination of the caries risk in children by whole school class, the number of the colony forming units of mutans streptococci and lactobacilli in the stimulated saliva, the buffer capacity of the saliva and some chosen clinical indicators of increased caries risk were determined and evaluated in 103 schoolchildren (7 to 10 years old) in the city of Zurich . Mutans streptococci in the saliva were found in 73% of the children and lactobacilli in 77% . In 11% of the children, neither of the microorganisms were found . Sixty-three percent of the children showed a strong buffer capacity of the saliva and 12% a small one . On the basis of these results and some selected clinical factors, 30% of the children were classified as patients with a high caries risk and are now following an intensive prophylaxis program.

Folia Microbiol (Praha), 1991, 36(3), 246 - 8
Effect of age, amount of inoculum and inoculation medium composition on lactic acid production from glucose by Lactobacillus casei subsp . rhamnosus; Martinkova L et al.; Effect of composition of the medium used for the inoculum cultivation, of the age and amount of the inoculum was investigated using a 3-L glass fermentor with a working volume of 1 L . The highest productivity of the culture was obtained when using a 20% (V/V) 1-d inoculum grown in the MRS medium . Yields of lactic acid were 88-97%, while the L(+)-isomer represented about 80% of the total product.

Arch Oral Biol, 1991, 36(7), 549 - 52
Effects of low-dose oral contraceptives on female whole saliva; Laine M et al.; The composition and flow rate of paraffin-stimulated whole saliva were analysed in 22 women, of whom 11 used oral contraceptives and 11 did not . Ten men served as the controls . The salivary samples were collected during one month (oral contraceptive users and men), or during one menstrual cycle (non-users) . The saliva analyses included flow rate, pH, buffer effect, sialic acid, thiocyanate, peroxidase, lysozyme, amylase, immunoglobulins A, G and M, total protein, mutans streptococci, lactobacilli, yeasts and total numbers of aerobic bacteria . The salivary buffer effect of oral contraceptive users was significantly (p less than 0.005) higher than that of non-users . All the other constituents showed intra- and interindividual variation in all groups, but with no apparent hormone-dependencyPIP: The flow rate and composition of whole saliva were analyzed in 11 women using low dose oral contraceptives in comparison with 11 menstruating women and 10 men . Paraffin-stimulated whole saliva samples were collected Monday, Wednesday and Friday mornings for 1 cycle or 1 month in all subjects, checked for pH and buffer effect (Dentobuff method, Orion Diagnostics, Espoo, Finland, a measure of bicarbonate content) immediately, and frozen for later assay of salivary lysozyme, amylase, peroxidase, thiocyanate, sialic acid, total protein, IgA, IgG, IgM, Mutans streptococci, Lactobacilli, yeasts and aerobic bacteria . The oral contraceptives taken were Marvelon (Organon, Holland) by 4 subjects, Microgynon (Leiras, Finland) by 1, and Trikvilar (Leiras) by 6 . The only significant differences between subject groups of cycle phases was a higher salivary buffer effect in oral contraceptive users than that seen in non-users, who resembled male controls . There was a wide individual variation in most values, but less variation in pH and buffer effect . Salivary buffer effect, which is correlated with HCO3-content and salivary flow, is also higher in late pregnancy .

Proc Finn Dent Soc, 1991, 87(4), 659 - 70
Experience and views of caries research and oral health; Luoma H; The main clinical and theoretical studies on caries etiology and prevention and on general health published by the author and his coworkers since the beginning of the 1960s are briefly reviewed . Among the caries prevention methods published by previous authors, the Finnish trials on fissure sealing and fluoride varnishing showed distinct preventive effects . On the basis of these and later supporting findings, these methods were rapidly and widely adopted in the dental health care of Finnish children and adolescents . A chlorhexidine-fluoride mouthrinsing solution, developed by the author, exhibited simultaneous reduction of both caries and gingivitis among high -risk children and this preparation or chlorhexidine-fluoride gels have been widely prescribed for risk subjects, especially those with a caries risk . Despite the good caries prevention results obtained through fluoridation of sugar products and in respective model studies, this procedure has not been passed for commercial use in Finland . The translocation of phosphorus, potassium and fluoride between microbes of dental plaque origin and their environment, including the respective elements of enamel origin, were presented as a partial explanation for the role of phosphates and fluoride in caries etiology and/or prevention . Animal experiments elucidated the killing mechanism of a high single fluoride intake and its prevention by magnesium with explanatory changes in cardiac calcium . On the other hand, experiments on prolonged intakes of low dietary fluoride by rats confirmed earlier findings on the potential of fluoride in preventing calcium salt imbalances in internal organs . This was accomplished with a fluoride intake sufficient for caries reduction . The ability of two strains of the mutans streptococci and a Lactobacillus to invade enamel and dentine and to destory these structures from the inside before the cavitation phase of caries was demonstrated with gnotobiotic rats . The marked caries reduction among Finnish children and adolescents within the past 20 years appears to be due to a number of factors.

Proc Finn Dent Soc, 1991, 87(4), 515 - 25
Sugar, fluoride, pH and microbial homeostasis in dental plaque; Marsh PD; Factors that may contribute to the maintenance or breakdown of the oral microflora have been studied in the laboratory using a mixed culture chemostat system . Carbohydrate type had relatively little influence of the proportions of individual species at neutral pH . In contrast, when the pH was allowed to fall following carbohydrate metabolism, the stability of the microflora was markedly perturbed . The proportions of Streptococcus mutans, Lactobacillus casei and Veillonella dispar increased and they became the predominant species, while levels of other Gram-negative organisms and S . gordonii declined . Low levels (1 mmol/l) of sodium fluoride (NaF) had little effect on the microflora at neutral pH . However, when the pH fell following carbohydrate metabolism, 1 mmol/l of NaF slowed acid production and, in so doing, reduced the inhibition of acid-sensitive species, and suppressed the selection of S . mutans under otherwise favourable conditions . These data (and others) suggest that the mode of action of fluoride in human beings might include a subtle but clinically significant antimicrobial effect . These findings have also led to the proposal of a modified hypothesis (the "ecological plaque hypothesis") to explain the role of the resident oral microflora in dental disease . The hypothesis also has implications for treatment and prevention strategies.

Klin Khir, 1991, (9), 50 - 2
{Surgical treatment of acute bacteroid purulent cholangitis}; Panov VA et al.; The results of treatment of 40 patients with acute purulent cholangitis developed against the background of choledocholithiasis are presented . Bacteroid of the kind B . fragilis (67.5% of cases), Fusobacterium, Lactobacillus sp . (30%) are the leading etiological factor of cholangitis . The indications for external and internal drainage of the bile ducts are substantiated . The ineffectiveness of internal drainage in this disease is demonstrated.

Gynakol Rundsch, 1991, 31(3), 153 - 60
{Vaccination against nonspecific bacterial vaginosis . Double-blind study of Gynatren}; Siboulet A; 167 patients suffering from nonspecific bacterial vaginoses were vaccinated in a double-blind, randomized, placebo-controlled trial . It appeared, during the study period of 14 months, that the vaccination with Gynatren, a lactobacillus vaccine, was significantly better than the placebo as concerns its therapeutical effect, but mainly as concerns its preventive effect (less reinfections) . The vaccine was very well tolerated . We conclude that vaccination with Gynatren is an effective measure to prevent recurrences of nonspecific vaginosis.

Caries Res, 1991, 25(5), 377 - 84
Factors associated with active and inactive root caries in patients with periodontal disease; Ravald N et al.; The aim of this study was to analyze a number of microbial, salivary, and dietary factors in patients with clinically active and inactive root caries . 147 patients, aged 30-78 years, referred for specialist treatment of periodontal disease, were randomly selected . 645 decayed and 539 filled root surfaces were found . Out of the carious lesions, 372 (58%) were recorded as clinically active and 273 (42%) as inactive . 30 patients showed no lesions (group 1), 46 had only fillings or inactive lesions (group 2), and 35 showed 1-2 (group 3) and 36 greater than or equal to 3 active lesions (group 4) . The lactobacillus count differed significantly between all groups, except group 1 vs . 2, and the mutans streptococcus count between groups 1 vs . 4 and 2 vs . 3 and 4 . Group 4 differed in plaque score from the other groups, and the salivary buffer effect differed between the inactive groups 1 and 2 and the active group 4 . By stepwise multiple regression analysis, it was shown that lactobacillus count, plaque index, salivary buffer effect, dietary habit index, and number of exposed root surfaces contributed significantly to the coefficient of determination.

Lab Delo, 1991, (3), 78 - 9
{A nutrient medium for isolating Lactobacilli}; Abrosimova NA et al.; The composition of and method for preparation of nutrient medium for the isolation of Lactobacilli from biologic material are described . The medium is simple to prepare, consists of only Soviet reagents, this making it available for laboratories in this country.

Biomed Mater Eng, 1991, 1(2), 115 - 25
Rapid counting method of living cells by fluorescent enzyme substrates; Sugata K et al.; The 5(and 6)-carboxyfluorescein diacetate (C-FDA) is used for a rapid and continuous counting of living cells . Nonfluorescent C-FDA is converted into fluorescent 5(and 6)-carboxyfluorescein (C-F) by the reaction with esterase, which is an enzyme of living cells . The conversion makes it possible to count the number of living cells by detecting fluorescence . Experimental results show that the living cells of beer's yeast, E . coli, and Lactobacillus bulgaricus can be detected by fluorescence . The flow cell system was used to experiment a continuous detection of living cells, so that the number of living cells of beer's yeast can be detected continuously . The proposed method can be applied to the on-line counting in the food plants.

J Biol Chem, 1990 Dec 25, 265(36), 22561 - 8
Molecular cloning and DNA sequence of lacE, the gene encoding the lactose-specific enzyme II of the phosphotransferase system of Lactobacillus casei . Evidence that a cysteine residue is essential for sugar phosphorylation; Alpert CA et al.; The gene coding for the lactose-specific Enzyme II of the Lactobacillus casei phosphoenolpyruvate-dependent phosphotransferase system, lacE, has been isolated by molecular cloning and expressed in Escherichia coli . The DNA sequence of the lacE gene and the deduced amino acid sequence are presented . The putative translation product comprises a hydrophobic protein of 577 amino acids with a calculated molecular mass of 62,350 Da . The deduced polypeptide has a high degree of sequence similarity with the corresponding lactose-specific enzymes II of Staphylococcus aureus and Lactococcus lactis . The sequence surrounding cysteine 483 was strongly conserved in the three proteins . The identity of the lacE product as the Enzyme IIlacL.casei was demonstrated by in vitro lactose phosphorylation assays using the protein expressed in E . coli . Single replacement of each of the histidine and cysteine residues by site-directed mutagenesis pointed to cysteine 483 as an amino acid residue essential for the phosphoryl group transfer reaction.

J Biol Chem, 1990 Dec 25, 265(36), 22554 - 60
Characterization of the lactose-specific enzymes of the phosphotransferase system in Lactococcus lactis; de Vos WM et al.; The plasmid-encoded lactose genes of the Lactococcus lactis phosphotransferase system encoding Enzyme IIIlac (lacF) and Enzyme IIlac (lacE) have been identified and cloned in Escherichia coli and L . lactis . Nucleotide sequence and transcription analysis showed that these genes are organized into a lactose-inducible operon with the gene order lacF-lacE-lacG-lacX, the latter two genes encoding phospho-beta-galactosidase and a 34-kDa protein with an unknown function, respectively . The lac-operon is immediately followed by an IS element that is homologous to ISS1 . Enzyme IIIlac was purified from L . lactis and determination of its NH2-terminal sequence demonstrated that the lacF gene starts with a TTG codon and encodes a 105 amino acid protein (Mr = 11416) . Cross-linking studies with the purified enzyme showed that Enzyme IIIlac is active as a trimer . A mutant lacF gene was identified in strain YP2-5 and appeared to encode Enzyme IIIlac containing the missense mutation G18E . The lacF gene could be expressed under control of vector-located promoter sequences resulting in overproduction of Enzyme IIIlac in E . coli and complementation of the L . lactis lacF mutant YP2-5 . The deduced amino acid sequence of Enzyme IIlac consists of 586 amino acids (Mr = 61562) and shows the characteristics of a hydrophobic, integral membrane protein . The deduced primary structures of the L . lactis Enzyme IIIlac and Enzyme IIlac are homologous to those of Staphylococcus aureus (72 and 71% identity, respectively) and Lactobacillus casei (48 and 47% identity, respectively) . In contrast, the organization of the lactose genes differs significantly between those Gram-positive bacteria . Heterogramic homology in specific domains was observed between the derived amino acid sequences of the lactose-specific enzymes and that of E . coli Enzyme IIIcel and Enzyme IIcel, which suggest a common function in the transport and phosphorylation of these structurally related beta-glucosides.

Semin Dermatol, 1990 Dec, 9(4), 300 - 4
Microbiology of specialized skin: the vulva; Elsner P et al.; Human vulvar skin is an example of specialized skin . This is not only true for its gross and microscopic anatomy and physiology, but also for its microbiology . To the microbiologist, the vulva consists of several distinct ecotopes . These are defined by the physical factors, especially occlusion, nutrient factors, and by the close proximity to the vagina, the urethra, and the anus, which may result in contamination with the flora typical for those sites . Of the vulva ecotopes, only the labia majora have been seriously studied . The microbial flora of the labia majora is characterized by a high density of microorganisms, as is typical for occluded areas of the body, by the presence of organisms common for intertriginous skin such as gram-negative rods, and by the carriage of organisms unique for the vulva and probably related to urethral and vaginal flora such as the nonpathogenic neisseria, lactobacilli, and Gardnerella vaginalis . Finally, the labia majora skin is a preferred site of Staphylococcus aureus carriage that can be of clinical and epidemiological relevance.

J Clin Microbiol, 1990 Dec, 28(12), 2621 - 6
Coaggregation of oral Candida isolates with bacteria from bone marrow transplant recipients; Hsu LY et al.; In vitro coaggregation between Candida species isolated from immunosuppressed bone marrow transplant recipients and oral bacteria was investigated . Each Candida strain showed a different pattern of coaggregation with the 22 bacterial strains studied . Two strains of Lactobacillus amylovorus isolated from separate bone marrow transplant patients and Fusobacterium nucleatum (VPI 10197) coaggregated with all Candida strains . Ten bacterial strains showed no coaggregation with the Candida strains . A variety of inhibition patterns were observed when coaggregating strains were first incubated with various sugars or subjected to heat treatment . Positive and negative results were generally consistent with all Candida strains . On the basis of the culture characteristics of the oral rinse specimens, relationships between the colonization of bacteria and yeasts and in vitro coaggregation were suggested.

Am J Gastroenterol, 1990 Dec, 85(12), 1646 - 8
Liver abscess complicating intratumoral ethanol injection therapy for HCC; Isobe H et al.; We report a patient who developed multiple liver abscesses and sepsis caused by lactobacilli after the percutaneous intratumoral injection of ethanol for hepatocellular carcinoma . We diagnosed the liver abscess at an early stage because of a the finding of gas on ultrasound and computed tomography . Blood cultures grew Gram-positive rods, which were of the Lactobacillus species . The patient responded to the administration of antibiotics, and his hepatic tumors have not recurred in the 7 months since treatment . This is the first report of liver abscess following percutaneous ethanol injection therapy.

An Fac Odontol, 1990 Dec, (26), 43 - 8
{Evaluation of a new colorimetric test (VIP) to determine the presence of lactobacillus in saliva}; Yorio VP et al.; This techniques using Rogosa agar modificated with green of bromocresol, placed into tubes (10 ml) containing 4 ml, was developed for qualitative estimation in saliva of lactobacilli in a quick form . We spotted with a pipette 0.1 ml of saliva dilution into different tubes with the culture medium previously mentioned . The tubes were incubated at 37 degrees C for 24 and 48 hours . The results obtained showed a great agreement with the number of latobacilli in the agar.

An Fac Odontol, 1990 Dec, (26), 27 - 31
{Comparative study of the adherence test and the Petry plaque count test of Streptococcus mutans in saliva}; Pivel L et al.; The Streptococcus mutans counts--added to lactobacili depicting test--are an useful instrument in cariology when determining the risk groups . In studies concerning a large number of patients the S . Mutans count in saliva test are the most accesible . Nevertheless, they are very expensive and also complicate to carry out . Simplified techniques which depict S . Mutans on the basis of adherence tests have been perfected . The most suitable from them, taking into account our working conditions, is the Matsukubo test . We deemed it interesting to correlate this test and the Gold medium count . The study has been carried out with three different populations using both techniques at the same time . As per the correlation indices obtained we conclude that the Matsukubo technique and the count have a significant correlation between them . Due to its low cost, the simplicity of its realization, as well as its easy reading it can be effectively used as a primary procedure when studying populations large in number . Through this method selection will be made of the patients to be studied applying more precise microbiological techniques.

Nichidai Koko Kagaku, 1990 Dec, 16(4), 429 - 40
{Microflora around the bracket by direct bonding system}; Abe M; The purpose of the present study is to clarify the influence of microflora in plaque of the brackets edge by direct bonding system and the cause of caries that is induced around the bracket during orthodontic treatment . The subjects were selected from the patients undergoing direct bonded orthodontic treatment and from the non-orthodontic patients . They were divided into four groups: those having no orthodontic treatment (control group), those having no caries around the bracket (group A) and those having caries around the bracket (groups B and C) . Sample plaques were collected from the initial tooth surface with control group, from the tooth surface around the bracket with group A, from the carious cavity around the bracket with group B and from the non-carious tooth surface around the bracket with group C . The isolation rates of microflora in dental plaque of the four groups were compared, and the following conclusions were obtained . 1 . Group A had almost same level with control group as to the proportion of each bacterium examined by shape and gram stain of microbiota . Group B had higher level of gram positive cocci than the other groups . 2 . Group A and control group had no difference as to the isolation rates of genera Streptococcus, Actinomyces and Lactobacillus . 3 . Group A had low level of S . mutans, was the same as control group . 4 . The isolation rate of each genus: 1) The isolation rate of genus Streptococcus was almost same in groups A, C and control group . Group B had higher than the other groups . 2) The isolation rate of genus Actinomyces was the highest in all groups . 3) The isolation rate of genus Lactobacillus was exceedingly low . 4) Groups B and C had significantly higher level of S . mutans group than group A and control group . Group B had significantly lower level of S . mitior than group A and control group . 5 . All four groups showed high level of biotype I, and biotype IV was observed in groups B and C . Biotype I was identified as S . mutans serotype c, biotype IV was observed as S . sobrinus serotype d.

J Dent Assoc S Afr, 1990 Dec, 45(12), 503 - 6
Preservation of the quantity of lactobacilli in samples from the oral cavity; Botha SJ; Transport media for the preservation of streptococci from oral samples have been described, but a suitable transport medium for the preservation of lactobacilli in oral samples is yet to be established . In this study MRS, ROGOSA, and modifications of these media were evaluated as transport media for the quantitative preservation of oral lactobacilli . Results indicated a survival of ca . 100 per cent oral lactobacilli for both media when stored at 4 degrees C for up to 72 h . A decrease in the survival rate was obtained upon storage at -196 degrees C and growth occurred upon storage at 20 degrees C . It was evident throughout that carbohydrate-free modifications of both media best supported the quantitative survival of oral lactobacili . Carbohydrate-free modifications of both MRS and ROGOSA are therefore recommended as preservative transport media for the quantity of oral lactobacilli in oral samples for limited time periods.

Oral Microbiol Immunol, 1990 Dec, 5(6), 346 - 51
Association of selected bacteria with the lesions of root surface caries; Bowden GH et al.; Plaque from the root surfaces of 165 subjects (mean age 65.5 years, 22-26 teeth/subject) was analysed for specific bacteria . Five subject groups were defined: A (DMFS 16.4), B (DMFS 55.9), C1 (DMFS 55.6), C2 (DMFS 57.0) and C3 (DMFS 48.1) . Groups C1 and C2 had unrestored root surface lesions; Group A, B and C3 were free of unrestored root caries and differed in their coronal caries experience . Streptococcus mutans was isolated more frequently from the root lesions in Groups C1 and C2 than from intact root surfaces in Group A . Streptococcus oralis, Streptococcus mitis 1 and Streptococcus sanguis were isolated more frequently from Group A . The percentage contribution that S . mutans made to plaque from lesions in Groups C1 and C2 was higher than that from plaque in Group A and Actinomyces viscosus serovar 2 contributed more to plaque in Group C1 than in samples from Group A . The percentage counts of Lactobacillus in plaque from lesions in Groups C1 and C2 were higher than those from intact roots in Groups A, B, and C3 . Subjects were also grouped on the presence of Lactobacillus and S . mutans in plaque samples . Samples with both organisms (n = 17) showed significantly higher isolation frequencies of specific strains of S . mitis 1 and also A . viscosus serovar 2 compared with samples of plaque containing S . mutans or Lactobacillus . Actinomyces naeslundii serovar 1 was not isolated from samples containing both S . mutans and Lactobacillus . The results confirm an association of S . mutans and Lactobacillus with root surface lesions and suggest a relationship between lesions and A . viscosus serovar 2.

Indian J Med Res, 1990 Dec, 92, 431 - 2
Preliminary observations on effect of Lactobacillus sporogenes on serum lipid levels in hypercholesterolemic patients; Mohan JC et al.; Short term hypolipidemic effects of oral L . sporogenes therapy (360 million spores/day in tablet form) were studied in 17 patients with type II hyperlipidemia in an open label fixed dose trial . Total serum cholesterol (330 +/- 55 mg/dl vs 226 +/- 46 mg/dl, P less than 0.001), LDL-cholesterol (267 +/- 58 mg/dl vs 173 +/- 54 mg/dl, P less than 0.001) and total cholesterol to HDL cholesterol and LDL-cholesterol to HDL-cholesterol ratios (P less than 0.001) were reduced significantly over a period of three months . HDL-cholesterol was marginally increased (43.6 +/- 7 mg/dl vs 46.8 +/- 8.9 mg/dl, P less than 0.05); however there was no change in serum triglyceride levels.

Agric Biol Chem, 1990 Dec, 54(12), 3211 - 9
Purification and characterization of an antihypertensive compound from Lactobacillus casei; Sawada H et al.; Antihypertensive compounds were purified from an extract of autologous Lactobacillus casei cell lysates . The most effective compounds were polysaccharide-glycopeptide complexes, found in the cell wall . The average molecular weight was estimated as 180,000 from gel filtration using Sephacryl S-300 . The polysaccharide moiety of the complexes consisted of glucose, rhamnose, and galactose, whereas the glycopeptide moiety consisted of N-acetylglucosamine, N-acetylmuramic acid, asparagine, glutamine, alanine, and lysine . The varieties of the components of these moieties were constant and independent of complex molecular size . When these complexes were orally administered to spontaneously hypertensive rats (SHR) and renal hypertensive rats (RHR) at doses of 1 mg/kg-body weight, systolic blood pressure (SBP) decreased by 10-20 mmHg 6 to 12 hr after administration without any change in heart rate . Appreciable hypotensive activity was lost by treating the complexes with hydrofluoric acid, which hydrolytically cleaves the phosphodiester bond between the polysaccharide and glycopeptide moiety.

J Biol Chem, 1990 Nov 5, 265(31), 18776 - 9
Saturation site-directed mutagenesis of thymidylate synthase; Climie S et al.; We have subjected 12 different codons of a synthetic Lactobacillus casei thymidylate synthase (TS) gene to saturation site-directed mutagenesis to create amino acid "replacement sets" at each of those positions . The target residues were chosen because they are highly conserved and because they are important for the structure and function of the protein as indicated by solution and structural studies . The mutagenesis procedure involved excision of a fragment of the synthetic gene containing the target codon, followed by its replacement with a mixture of oligonucleotides which code for all 20 amino acids and the amber stop codon . TS mutants were identified by DNA sequencing, and catalytically active mutants were identified by genetic complementation using a Thy- strain of Escherichia coli . Only 3 of the 12 target amino acids examined were essential for TS activity; and of the 125 total mutants identified, 57 were catalytically active . These results point to a high degree of plasticity of TS in accommodating function with structural change.

J Dairy Sci, 1990 Nov, 73(11), 3050 - 8
Factors controlling histamine production in Swiss cheese inoculated with Lactobacillus buchneri; Sumner SS et al.; Swiss cheese was made from raw milk inoculated with various concentrations of a histamine-producing strain of Lactobacillus buchneri . Histamine production in these cheeses was proportional to the initial number of L . buchneri present in the raw milk . The highest inoculum level tested was 10(5) L . buchneri/ml . This cheese contained 80 mg of histamine/100 g of cheese after 90 d of storage . Only 15 mg of histamine/100 g of cheese were detected after 90 d at the lowest inoculum level, 10(2) L . buchneri/ml . No histamine was detected in any of the Swiss cheese samples until after the brining stage . Perceptible growth of L . buchneri also did not occur until after the warm room treatment . Therefore, control of histamine formation in Swiss cheese requires control of the number of histamine-producing bacteria in the raw milk . A 5.5% NaCl concentration in DeMan, Rogosa, Sharpe (MRS) broth inhibited the production of histamine by L . buchneri, but the concentrations of NaCl typically found in Swiss cheese were not inhibitory . The histamine-producing isolate of L . buchneri survived heating at 49 to 80 degrees C for 10 min, suggesting that this organism would easily survive the normal heating process applied to raw milk used prior to making Swiss cheese.

ASDC J Dent Child, 1990 Nov-Dec, 57(6), 428 - 32
Occlusal hidden caries: a bacteriological profile; Weerheijm KL et al.; Eleven teeth from nine patients with occlusal caries lesions beneath an apparently intact enamel surface were treated . Two dentine samples, one from the dentinoenamel junction (Sample A) and one just before all the caries appeared to be removed clinically (Sample B), were taken under aseptic conditions and examined for bacteria . In all cases, the A samples and in ten cases the B samples contained mutans streptococci, lactobacilli or both, while in ten cases the dentine after opening was soft with a light color . This suggests that we are dealing with active caries lesions, which should be treated as such . The salivary data of the patients group were compared with the salivary data of the control group . Although the buffer capacity of the groups were not significantly different (chi-square), further analysis revealed that a significant relationship could be found between the group and the buffer capacity (Kendall's Tau C) . While the other salivary components (numbers of mutants streptococci per ml saliva and the secretion rate) showed no significant differences . Unfortunately these occlusal caries lesions are not detected with the present criteria used in epidemiological surveys.

J Dent Res, 1990 Nov, 69(11), 1712 - 6
An intra-oral appliance study of the plaque microflora associated with early enamel demineralization; Macpherson LM et al.; An intra-oral appliance model was used to investigate the composition of the plaque microflora associated with early enamel demineralization . Enamel sections, with exposed windows, were mounted on lower removable appliances, and the devices were worn by volunteers for three-week periods under three experimental conditions . These were: (1) "normal" plaque conditions, (2) extra-oral sucrose applications nine times daily, and (3) inoculation of each volunteer's own mutans streptococci onto the test sites and sucrose applications as described for (2) . After 21 days, the plaque overlying each window was removed, and the bacterial composition was determined . Changes in mineral content of the associated enamel were measured by microradiography and microdensitometry, and the total mineral loss (delta z) that had occurred at each site was calculated . The 144 sites studied were divided into four demineralization groups by delta z value, with an increase in mineral loss from group 1 to group 4 . A progressive and significant increase in the isolation frequency of mutans streptococci occurred from delta z group 1 to group 4 sites . These organisms were isolated from the plaque of every location with enamel mineral loss of over 1000 delta z units, but were not detected in 27% of the group 3 sites . Lactobacilli comprised 2% to 3% of the total cultivable microflora in groups 1-3 sites, but were found in significantly higher proportions (18%) at those enamel sites experiencing the most extensive mineral loss (group 4) . No significant relationship was found between demineralization and the levels of Actinomyces species or Veillonella.(ABSTRACT TRUNCATED AT 250 WORDS)

J Dent Res, 1990 Nov, 69(11), 1706 - 11
The effect of sucrose application and implantation of mutans streptococci on the microbial composition of three-week experimental plaque--an in situ study; Macpherson LM et al.; This study describes the predominant cultivable microflora of three-week-old plaque samples obtained from human enamel sites, on the basis of microbial identification of over 9000 fresh isolates . Lower removable appliances, on which were mounted enamel sections and slabs, were worn by five young adult subjects under three experimental protocols . These were (1) 'normal' plaque conditions, (2) extra-oral sucrose applications nine times daily, and (3) inoculation of each subject's own mutans streptococci onto the enamel test sites and sucrose applications, as described above . With the exception of slightly higher proportions of Gram-negative bacilli associated with slab plaque following sucrose application, no significant differences in percentage or absolute counts of organisms were found between normal and sucrose plaques . The inoculation of mutans streptococci, combined with extra-oral sucrose applications, was associated with significantly higher percentages and absolute mean counts of both mutans streptococci and lactobacilli, and lower proportions of S . sanguis and S . oralis . Although the isolation frequency of mutans streptococci increased in all subjects and the overall mean proportion rose following inoculation, considerable inter-subject variation was seen in mean percentage counts of these organisms isolated from the three-week plaque samples.

J Bacteriol, 1990 Nov, 172(11), 6339 - 47
Cloning, expression, and nucleotide sequence of the Lactobacillus helveticus 481 gene encoding the bacteriocin helveticin J; Joerger MC et al.; Lactobacillus helveticus 481 produces a 37-kDa bacteriocin called helveticin J . Libraries of chromosomal DNA from L . helveticus were prepared in lambda gt11 and probed for phage-producing fusion proteins that could react with polyclonal helveticin J antibody . Two recombinant phage, HJ1 and HJ4, containing homologous inserts of 350 and 600 bp, respectively, produced proteins that reacted with antibody . These two phage clones specifically hybridized to L . helveticus 481 total genomic DNA but not to DNA from strains that did not produce helveticin J or strains producing unrelated bacteriocins . HJ1 and HJ4 lysogens produced beta-galactosidase fusion proteins that shared similar epitopes with each other and helveticin J . The intact helveticin J gene (hlv) was isolated by screening a library of L . helveticus chromosomal DNA in lambda EMBL3 with the insert DNA from phage HJ4 as a probe . The DNA sequence of a contiguous 3,364-bp region was determined . Two complete open reading frames (ORF), designated ORF2 and ORF3, were identified within the sequenced fragment . The 3' end of another open reading frame, ORF1, was located upstream of ORF2 . A noncoding region and a putative promoter were located between ORF1 and ORF2 . ORF2 could encode an 11,808-Da protein . The L . helveticus DNA inserts of the HJ1 and HJ4 clones reside within ORF3, which begins 30 bp downstream from the termination codon of ORF2 . ORF3 could encode a 37,511-Da protein . Downstream from ORF3, the 5' end of another ORF (ORF4) was found . A Bg/II fragment containing ORF2 and ORF3 was cloned into pGK12, and the recombinant plasmid, pTRK135, was transformed into Lactobacillus acidophilus via electroporation . Transformants carrying pTRK135 produced a bacteriocin that was heat labile and exhibited an acitivity spectrum that was the same as that of helveticin J.

Zh Mikrobiol Epidemiol Immunobiol, 1990 Nov, (11), 6 - 9
{The effect of a preparation made from Solco lactobacteria on the survival rate and intestinal microflora of irradiated animals}; Bossart V et al.; Lactobacillus acidophilus strain Lat 11/83 Solco has been used for the normalization of intestinal microflora in experimental post-irradiation intestinal dysbacteriosis in mice . The results of these experiments indicate that live Solco lactobacteria, introduced intragastrically, facilitate the enhancement of the survival rate of irradiated animals and the normalization of microflora in their gastrointestinal tract . The strain can be used as bacterial preparation for the regulation of intestinal microbiocenosis.

Poult Sci, 1990 Nov, 69(11), 1966 - 73
Influence of a dried Bacillus subtilis culture and antibiotics on performance and intestinal microflora in turkeys; Jiraphocakul S et al.; Two experiments, each involving a 3 x 2 factorial design, were conducted with Large White Nicholas turkeys . The first experiment involved three antibiotic treatments: an unmedicated control diet, the diet plus 44 ppm of penicillin-streptomycin (1:3), and the diet plus 44 ppm of Zn bacitracin; each diet was fed in the presence and absence of a dried Bacillus subtilis culture to females 0 to 16 wk of age . Antibiotic supplements increased body weight at 12 (P less than .05) and 16 (P less than .001) wk of age . Body weight and feed efficiency were not significantly affected by feeding the B . subtilis culture in this experiment . The dietary B . subtilis culture significantly increased B . subtilis counts in the crop and cecum but failed to influence intestinal Lactobacillus or Escherichia coli counts . The second experiment also involved three antibiotic treatments: an unmedicated control diet, 44 ppm of Zn-bacitracin, and 2.2 ppm of bambermycins, and each diet was fed in the presence and absence of the dried B . subtilis culture to male birds from 0 to 20 wk of age . Increased body weight gain was observed in birds receiving the B . subtilis culture at 12 wk (P less than .01) . Feed efficiency of birds receiving the B . subtilis culture was improved (P less than .05) at 20 wk . Birds receiving bambermycins had greater body weights (P less than .05) at 12 and 16 wk of age than birds receiving Zn bacitracin or the control diet . Livability was not affected by the B . subtilis culture or the antibiotic treatments in either experiment.

J Appl Bacteriol, 1990 Nov, 69(5), 648 - 54
Antimicrobial activity of Leuconostoc gelidum against closely related species and Listeria monocytogenes; Harding CD et al.; A newly isolated strain of Leuconostoc gelidum was evaluated for its ability to inhibit a wide spectrum of lactic acid bacteria, meat spoilage bacteria and food-related human pathogens, including Listeria monocytogenes . It was inhibitory to most of the lactobacilli, all the leuconostocs, and three strains of L . monocytogenes when tested both by direct and well diffusion methods . Cell-free extract retained activity after 60 min at 100 degrees C but was sensitive to protease . Dialysis suggested a molecular weight in excess of 10(4) daltons . The inhibitory effect was bactericidal and rapid.

Czas Stomatol, 1990 Nov-Dec, 43(11-12), 666 - 71
{Quantitative and qualitative characteristics of the bacterial flora of saliva and dental plaque in artificially fed children}; Szczepanska J et al.; Stomatological and bacteriological studies were carried out in 66 children aged 1-5 years divided into two groups: I--without caries, II--with carietic lesions typical of the so called "bottle caries", that is with carietic defects on the vestibular surfaces of upper incisors and on masticating surfaces of first molars . No differences of qualitative character were found in the bacterial flora of the saliva and the dental plaques in children with "bottle caries" in relation to those without caries . A significant correlation was noted between the quantity of S . mutans and Lactobacillus in the saliva or dental plaque and the intensity of caries . These results confirm the suggestions of other authors that Str . mutans plays an important role in caries and that it is the prevailing species among acid-producing flora in children with bottle caries.

Biochemistry, 1990 Oct 16, 29(41), 9561 - 72
Properties of bacteriophage T4 thymidylate synthase following mutagenic changes in the active site and folate binding region; LaPat-Polasko L et al.; Amino acid replacements have been introduced in specific sites of bacteriophage T4 thymidylate synthase (T4-TS) to assess the role that these changes have on enzyme activity . Each of the conserved amino acids in the active-site region of T4-TS was modified, and the effects that these changes had on the kinetic and physical properties of this enzyme were measured . The mutations introduced were Pro-155-Ala (P155A), Cys-156-Ser (C156S), and His-157-Val (H157V) with the resulting synthases possessing kcat's of 10.3, 0.008, and 2.70 s-1, respectively, relative to that of the wild-type enzyme of 11.8 s-1 . Equilibrium dialysis was performed on the wild-type and mutant enzymes to determine the binding constants for 2'-deoxyuridylate and 5-fluoro-2'-deoxyuridylate, and while in most cases the extent of binding of these nucleotides to the mutant proteins was reduced when compared with wild-type TS, the number of binding sites involved remained about 1 or less for the binary complex and almost 2 for the ternary complex . Heat and urea stability studies revealed that the mutant with the highest enzyme activity, P155A, was the most unstable, while spectrofluorometric analyses revealed that the structures of P155A and H157V were perturbed relative to the C156S and wild-type TSs . These studies are in agreement with others implicating the phylogenetically conserved active-site cysteine as playing an essential mechanistic role in the catalytic process promoted by TS . The proximal amino acids on either side of this cysteine, although also highly conserved, do not appear to affect the catalytic mechanism directly, but may do so indirectly through their influence on the conformation at the active site as well as other regions of the enzyme . Amino acids replacements were introduced also into the folate and deoxynucleotide 5'-phosphate binding sites of the T4-phage TS to ascertain the potential role that these amino acids play in the catalytic process . These positions were selected on the basis of previous chemical modification and X-ray crystallographic studies on Lactobacillus casei TS . Amino acid residues 48 and 49, which are in the putative folate binding site, were converted from lysines to arginines; in the former case, the mutated enzyme had less than 7% of the wild-type activity while in the latter, the mutated enzyme still retained about 60% of its activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Biochemistry, 1990 Oct 16, 29(41), 9660 - 7
NMR studies of multiple conformations in complexes of Lactobacillus casei dihydrofolate reductase with analogues of pyrimethamine; Birdsall B et al.; 1H and 19F NMR signals from bound ligands have been assigned in one- and two-dimensional NMR spectra of complexes of Lactobacillus casei dihydrofolate reductase with various pyrimethamine analogues (including pyrimethamine {1, 2,4-diamino-5-(4'-chlorophenyl)-6-ethylpyrimidine}, fluoropyrimethamine {2, 2,4-diamino-5-(4'-fluorophenyl)-6-ethylpyrimidine}, fluoronitropyrimethamine {3, 2,4-diamino-5-(4'-fluoro-3'-nitrophenyl) -6-ethylpyrimidine}, and methylbenzoprim {4, 2,4-diamino-5-{4'- (methylbenzylamino)-3'-nitrophenyl}-6-ethylpyrimidine}) . The signals were identified mainly by correlating signals from bound and free ligands by using 2D exchange experiments . Analogues (such as 1 and 2) with symmetrically substituted phenyl rings give rise to 1H signals from four nonequivalent aromatic protons, clearly indicating the presence of hindered rotation about the pyrimidine-phenyl bond . Analogues containing asymmetrically substituted aromatic rings (such as 3 and 4) exist as mixtures of two rotational isomers (an enantiomeric pair) because of this hindered rotation and the NMR spectra revealed that both isomers (forms A and B) bind to the enzyme with comparable, though unequal, binding energies . In this case two complete sets of bound proton signals were observed . The phenyl ring protons in each of the two forms experience essentially the same protein environment (same shielding) as that experienced by the corresponding protons in bound pyrimethamine: this confirms that forms A and B correspond to two rotational isomers resulting from approximately 180 degrees rotation about the pyrimidine-phenyl bond, with the 2,4-diaminopyrimidine ring being bound similarly in both forms . The relative orientations of the two forms have been determined from NOE through-space connections between protons on the ligand and protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Scand J Dent Res, 1990 Oct, 98(5), 391 - 400
Root surface caries and associated factors; Fure S et al.; The prevalence of root surfaces caries in 208 randomly selected 55, 65, and 75-yr-old Swedes was related to the frequency of coronal caries, the number of remaining teeth and to bacteriologic, salivary, and dietary variables . At least one decayed or filled root surface was found in 89% of the individuals and all of those had also experienced coronal caries . The frequency of root surface caries was positively correlated to the frequency of coronal decay and negatively correlated to the number of remaining teeth and exposed root surfaces . The study shows that the same factors which are associated with enamel caries seem to be of importance in determining the development of root surface caries . The variation in the frequency of root surface caries was best explained by the salivary levels of mutans streptococci and lactobacilli, the percentage of surfaces harboring plaque and the frequency of carbohydrate intake . Other contributory factors were the saliva secretion rate and the buffer capacity.

J Biochem (Tokyo), 1990 Oct, 108(4), 568 - 71
Structure of polysaccharide-peptidoglycan complex from the cell wall of Lactobacillus casei YIT9018; Nagaoka M et al.; The isolation and analysis of the polysaccharide-peptidoglycan complexes of Lactobacillus casei YIT9018 are presented . Two polysaccharide-peptidoglycan complexes, PS-PG1 and PS-PG2, were solubilized from the heat-killed cell by treatment with N-acetylmuramidase . PS-PG1 was composed of glucose, rhamnose, and small amount of galactose and glucosamine . PS-PG2 was composed of glucose, rhamnose, galactosamine, and glucosamine . The ratio by weight of these fractions was about 1:8 . PS-PG2 was analyzed in detail . Smith degradation and deamination of this complex yielded oligosaccharide units . The results of methylation analysis of these units and intact PS-PG2 led to the most probable structure of PS-PG2: (formula; see text)

Int J Food Microbiol, 1990 Oct, 11(2), 127 - 34
Immunofluorescence microscopic studies on distribution of Lactobacillus kefiranofaciens and Lactobacillus kefir in kefir grains; Arihara K et al.; Immunofluorescence staining was applied to observe distribution of two Lactobacillus species in kefir grains with cauliflower floret forms . Kefiran-producing, encapsulated Lactobacillus kefiranofaciens was located all over the grain and increased toward the center, while Lactobacillus kefir populated only a small region at the surface layers.

Community Dent Oral Epidemiol, 1990 Oct, 18(5), 249 - 52
Dental caries, mutans streptococci, lactobacilli, and saliva secretion rate in adults; Klock B et al.; In 718 Swedish patients, equally divided into four age groups (19-25, 26-45, 46-60, greater than 60 yr), salivary levels of mutans streptococci and lactobacilli, saliva secretion rate, and DMFS were registered . No significant differences were found between the various age groups either in salivary factors or in caries (D) . Number of missing (M) and filled (F) surfaces increased with age . Prevalence of root caries, which increased with age, was significantly correlated to number of exposed root surfaces independent of age . Of the total study group, 50% had greater than or equal to 10(6) mutans streptococci and 40% had greater than or equal to 10(5) lactobacilli per mL saliva . Three percent had a saliva secretion rate of less than or equal to 0.5 mL/min . Correlation analyses showed that both mutans streptococci and lactobacilli significantly correlated to the caries prevalence but the r-value never exceeded 0.34.

Clin Microbiol Rev, 1990 Oct, 3(4), 335 - 44
Is there a role for lactobacilli in prevention of urogenital and intestinal infections?
Reid G, Bruce AW, McGroarty JA, Cheng KJ, Costerton JW.
This review describes the importance of microbial adhesion in the ecology of the urogenital and intestinal tracts and the influence of host and microbial factors in bacterial interference . In a recent revival of interest in bacterial interference, lactobacillus administration has been studied as a means of treating and preventing disease . Although evidence is conflicting, Lactobacillus acidophilus appears to be involved in beneficial antagonistic and cooperative reactions that interfere with establishment of pathogens in the gastrointestinal tract . The mechanisms of action are believed to involve competitive exclusion and production of inhibitory substances, including bacteriocins . These characteristics, as well as demonstrated adherence abilities in vitro, led to selection of certain Lactobacillus strains for clinical studies of cystitis . Weekly intravaginal Lactobacillus therapy reduced the recurrence rate of uncomplicated lower urinary tract infections in women . Use of Lactobacillus strains resistant to Nonoxynol-9, a spermicide that kills members of the protective normal vaginal flora, may have potential for use in women with recurrent cystitis using this contraceptive agent . In veterinary studies, bacterial interference by administration of probiotics has also been beneficial in disease prevention in animals . Carefully selected bacterial mixtures integrate with the gastrointestinal flora of the animals and can confer disease resistance and improve physiological function . Additional human and animal trials are needed to determine the practical, long-term usefulness of bacterial interference as a protective mechanism against infectious diseases.

J Anim Sci, 1990 Oct, 68(10), 3392 - 8
Effects of microbial supplements containing yeast and lactobacilli on roughage-fed ruminal microbial activities; Dawson KA et al.; Effects of two microbial feed supplements on microbial activities in rumen-stimulating cultures and the rumens of steers fed a fescue hay-based roughage diet were evaluated . The yeast culture supplement contained Saccharomyces cerevisiae (1.4 to 4.2 x 10(9) colony-forming units {cfu}/g), whereas the mixed microbial supplement contained yeast, lactobacilli and enterococci (1.4 to 2.7 x 10(9) cfu/g, 1.2 to 2.3 x 10(9) cfu/g, and 1.5 to 2.6 x 10(10) cfu/g, respectively) . Concentrations of viable yeast cells were increased consistently in continuous cultures and rumens of steers receiving either supplement (1 g/kg of feed) . However, neither supplement consistently altered the relative concentrations of volatile fatty acids or ammonia in continuous cultures and rumens of steers . The pH tended to be greater (P = .13) in continuous cultures receiving yeast culture supplement than in cultures receiving the unsupplemented diet (6.50 vs 6.36), but pH in the rumens of steers was not affected by the supplements . Concentrations of cellulolytic microorganisms in cultures and the rumens of steers receiving supplements containing only yeast were from 5 to 40 times greater than those observed in cultures or steers receiving the unsupplemented diet . Supplements that had been treated with heat (121 degrees C for 15 min) to inactive yeast cells did not alter the concentrations of cellulolytic bacteria in rumen-stimulating cultures . These results suggest that live yeast culture supplements stimulate growth of cellulolytic microorganisms in the rumen.

J Bacteriol, 1990 Oct, 172(10), 5670 - 6
Spontaneous deletion formation within the beta-galactosidase gene of Lactobacillus bulgaricus; Mollet B et al.; To investigate the genetic stability of the dairy organism Lactobacillus bulgaricus, we have analyzed 107 spontaneous mutations of the beta-galactosidase gene of this organism . Ten of these mutations were DNA rearrangements giving rise to different deletions, located predominantly within a small hot spot area . The DNA sequences of the different deletion junctions have been determined . The analysis showed that the deletions can be divided into two classes, depending on the presence of short direct-repeat sequences at the deletion endpoints and on the length of the deleted sequences . Possible mechanisms of these deletion formations and the involvement of inverted-repeat sequences that may enhance slipped DNA mispairing are discussed.

Oral Microbiol Immunol, 1990 Oct, 5(5), 288 - 97
A IIIman protein is involved in the transport of glucose, mannose and fructose by oral streptococci; Bourassa S et al.; We show in this article that the transport of glucose, mannose and fructose by the phosphoenolpyruvate: mannose phosphotransferase system of oral streptococci requires the participation of a protein component that we have called IIIman . This protein was purified from Streptococcus salivarius by chromatography on DEAE-cellulose, DEAE-TSK, hydroxyapatite, and Dyematrex Green A . The purified protein migrated as a 38,900 molecular weight protein on a sodium dodecyl sulfate polyacrylamide gel . However, electrophoretic analysis of phosphoproteins and Western blot experiments indicated the presence in membrane-free cellular extracts of S . salivarius of 2 different forms of IIIman having molecular weights of 38,900 and 35,200 . The presence of the high-molecular-weight form of IIIman was observed by immunodiffusion, Western blot and phosphorylation by {32}PEP in S . salivarius, Streptococcus mutans, Streptococcus sobrinus, and Streptococcus lactis but not in Streptococcus faecium, Staphylococcus aureus, Bacillus subtilis and Lactobacillus casei . Antibodies directed against the IIIman of S . salivarius did not react with the IIIman of Escherichia coli.

Cesk Pediatr, 1990 Oct, 45(10), 587 - 90
{Immunobiologic properties of lactobacilli}; Mihal V et al.; The authors investigated in experiments on mice immunobiological properties of selected strains of lactobacilli (Lbc . acidophilus, Lbc . casei and Lbc . delbruecki) . Their immunostimulating action was evaluated from the migrating capacity of lymphocytes into the interepithelial spaces and lamina propria mucosae of the gut . The most marked changes were observed in the group of animals to whom Lbc . acidophilus and Lbc . casei was administered for two weeks by a gastric tube . The protective properties of lactobacilli on the course and development of model infections (virus of encephalomyocarditis) was greatest in mice given Lbc . casei and Lbc . acidophilus by the intraperitoneal route four days before infection . At the end of the two-week period in the Lbc . casei group 66% mice survived and in the Lbc . acidophilus group 34% . The ability of lactobacilli to influence the interferon producing activity was investigated in vitro on a model of peritoneal cells obtained from premedicated mice . The lactobacilli strains themselves did not have interferon inducing properties . However, when the interferon producing capacity of peritoneal cells was assessed after administration of the viral inducer (virus of Newcastle disease) the capacity was much higher, when compared with controls.

Lett Appl Microbiol, 1990 Oct, 11(4), 214 - 9
Cloning and expression of alpha-amylase from Bacillus amyloliquefaciens in a stable plasmid vector in Lactobacillus plantarum; Jones S et al.; Lactobacillus plantarum is used in a wide range of agricultural and food fermentations . In this paper we report the introduction of alpha-amylase into the organism from Bacillus amyloliquefaciens on a stable recombinant plasmid . The genetically manipulated organism grew on MRSB medium supplemented with starch and it may be a prototype for the development of lactobacilli able to use an increased range of substrates in commercial fermentations.

Gene, 1990 Sep 28, 94(1), 61 - 7
Cloning, expression and sequence analysis of an endolysin-encoding gene of Lactobacillus bulgaricus bacteriophage mv1; Boizet B et al.; The lysA gene specifying an endolysin of Lactobacillus delbrueckii subsp . bulgaricus bacteriophage mv1, was cloned and expressed in Escherichia coli . The 4.05-kb restriction fragment containing this gene was analysed by restriction and deletion mapping, and by subcloning . The nucleotide sequence of a 1150-bp fragment coding for an active lysin was determined . The lysA gene consists of 585 bp and codes for a protein of a deduced Mr of 21,120, which agrees with the size based on in vivo transcription/translation studies . The deduced amino acid sequence of the mv1 lysin (LysA) was compared to that of other known lytic enzymes . Significant homology was observed with the N-terminal portion of the muramidase of the fungus Chalaropsis and that of the muramidase of the Streptococcus pneumoniae phage Cp-1, suggesting that LysA might be a muramidase . In E . coli, the cloned lysA gene was able to complement the muramidase-defective bacteriophage lambda Ram5, proving that the products of these two genes are interchangeable . The lysA gene is preceded by an open reading frame with unknown function and no characteristic prokaryotic promoter sequences could be detected upstream from lysA, suggesting that this gene is part of an operon.

Biochemistry, 1990 Sep 4, 29(35), 8063 - 9
Role of lysine-54 in determining cofactor specificity and binding in human dihydrofolate reductase; Huang S et al.; Lysine-54 of human dihydrofolate reductase (hDHFR) appears to be involved in the interaction with the 2'-phosphate of NADPH and is conserved as a basic residue in other species . Studies have suggested that in Lactobacillus casei dihydrofolate reductase Arg-43, the homologous residue at this position, plays an important role in the binding of NADPH and in the differentiation of Km values for NADPH and NADH . A Lys-54 to Gln-54 mutant (K54Q) of hDHFR has been constructed by oligodeoxynucleotide-directed mutagenesis in order to study the role of Lys-54 in differentiating Km and Kcat values for NADPH and NADH as well as in other functions of hDHFR . The purpose of this paper is to delineate in quantitative terms the magnitude of the effect of the Lys-54 to Gln-54 replacement on the various kinetic parameters of hDHFR . Such quantitative effects cannot be predicted solely on the basis of X-ray structures . The Km for NADPH for the K54Q mutant enzyme is 58-fold higher, while the Km for NADH for K54Q is only 3.9-fold higher than that of the wild type, indicating that the substitution of Lys-54 with Gln-54 decreases the apparent affinity of the enzyme for NADPH dramatically, but has a lesser effect on the apparent affinity for NADH.(ABSTRACT TRUNCATED AT 250 WORDS)

Biochim Biophys Acta, 1990 Sep 3, 1040(2), 287 - 93
Purification and characterization of uridine and thymidine phosphorylase from Lactobacillus casei; Avraham Y et al.; Uridine and thymidine phosphorylases have been purified to homogeneity from crude extracts of Lactobacillus casei . Both enzymes had an apparent molecular mass of about 80 kDa . Uridine phosphorylase consisted of four identical subunits while thymidine phosphorylase was composed of two identical ones . The sequence of 23 amino-acid residues from its N-terminal end was analyzed . Uridine phosphorylase had a Km of 5.0 x 10(-3) M for uridine and 1.24 x 10(-1) M for phosphate, while thymidine phosphorylase had a Km of 1.32 x 10(-1) M for thymidine and 1.0 x 10(-1) M for phosphate . Uridine phosphorylase was equally active with uridine and 5-methyluridine, but had a low activity towards thymidine . Its activity was inhibited competitively by 3-O-methyl-alpha D-glucopyranoside, on the other hand thymidine phosphorylase activity was not affected by this compound . Thymidine phosphorylase showed specificity towards the deoxyribosyl moiety of the substrate . In addition, it required a nonsubstituted pyrimidine moiety or one which was substituted in position 5 . The pattern of the double-reciprocal plots of the initial velocities vs . the concentrations of either one of the substrates, and the product inhibition kinetics, indicated that the catalytic mechanism of both enzymatic reactions is sequential rather than Ping-Pong and that the sequence of the addition of the substrates is random (rapid equilibrium) . In the case of the uridine phosphorylase-catalyzed reaction, the products are also released randomly, while in the thymidine phosphorylase-catalyzed reaction deoxyribose 1-phosphate is released after thymine.

Obstet Gynecol, 1990 Sep, 76(3 Pt 1), 407 - 13
Microbiologic efficacy of intravaginal clindamycin cream for the treatment of bacterial vaginosis; Hillier S et al.; Bacterial vaginosis is characterized by replacement of the normal Lactobacillus-predominant vaginal flora with Gardnerella vaginalis, anaerobic bacteria, and Mycoplasma hominis . The present study evaluated the vaginal flora of women with bacterial vaginosis before and after treatment with intravaginal clindamycin cream . Sixty-seven nonpregnant women with symptoms and signs of bacterial vaginosis, and without other genital tract infections, were randomly assigned to receive placebo cream or 0.1, 1, or 2% clindamycin cream . Quantitative vaginal cultures for facultative and anaerobic bacteria and genital mycoplasmas were performed at enrollment and at 4-7 days and 4-5 weeks after completion of therapy . At enrollment, G vaginalis was recovered from 99%, Bacteroides sp from 94%, Peptostreptococcus sp from 81%, and M hominis from 58% of the 67 women with bacterial vaginosis . The vaginal cultures yielded a median of 12 isolates per specimen, with equal numbers of aerobic and anaerobic species . The mean log concentration was 1.2 X 10(9) cfu/mL for aerobic and 2.6 X 10(8) cfu/mL for anaerobic bacteria . After treatment, the frequency and concentration of bacteria per milliliter of vaginal fluid decreased for G vaginalis, Bacteroides sp, Peptostreptococcus sp, and M hominis . The 2% clindamycin cream had the greatest effect on the bacterial vaginosis-associated flora and resulted in clinical resolution of bacterial vaginosis in 15 (94%) of 16 women . Treatment with lower concentrations of clindamycin cream had less effect on the vaginal flora and resulted in clinical cure in 25 (71%) of 35 women . Therapy was associated with an increase in the frequency and concentration of Lactobacillus, and a probably transient increase in the frequency of Escherichia coli and Enterococcus.(ABSTRACT TRUNCATED AT 250 WORDS)

FEMS Microbiol Rev, 1990 Sep, 7(1-2), 103 - 11
Uncommon pathways of metabolism among lactic acid bacteria; London J; A small number of lactic acid bacteria possess the ability to derive energy from organic molecules not utilized by the vast majority of representatives of this large group of microorganisms . Thus, strains of Lactobacillus casei and enterococci readily grow at the expense of substrates such as gluconate, malate and pentitols . Transport of gluconate and pentitols is catalysed by phosphotransferase systems unique to these bacteria . Similarly, the initial steps in pentitol dissimilation are mediated by enzymes found only in Lb . casei and Streptococcus avium.

J Appl Bacteriol, 1990 Sep, 69(3), 326 - 31
Comparison of quantitative and qualitative methods of detecting hydrogen peroxide produced by human vaginal strains of lactobacilli; Fontaine EA et al.; A quantitative method was developed for the measurement of micromolar quantities of H2O2 produced in Rogosa broth and peptonized milk broth by vaginal strains of lactobacilli isolated from women . The production of substantial amounts reproducibly was dependent on the growth of the organisms in acid media (pH less than or equal to 6.0) under anaerobic or micro-aerophilic conditions with continuous agitation . The addition to the media of the enzyme inhibitor, 3-amino-1,2,4-triazole, with or without catalase sometimes induced the production of H2O2 especially in non-agitated cultures . However, other agents such as concanavalin and o-dianisidine had no enhancing effect, and catalase or peroxidase alone completely inhibited H2O2 production . The H2O2 produced in the acid media was stable for more than a month at 5 degrees C but not in media at pH greater than or equal to 7.0 . Of five strains of lactobacilli tested by the quantitative method and by a chromogenic qualitative method (Rogosa-catalase or -per-oxidase agar), three consistently produced H2O2 measurable by the former method, but none did so after growth of the organisms on Rogosa-catalase/peroxidase agar which suggested that the qualitative method was unreliable . The fact that H2O2 was produced in substantial quantities by some strains and not at all by others enabled H2O2-producers and non-producers to be distinguished easily.

J Appl Bacteriol, 1990 Sep, 69(3), 311 - 20
Lactobacilli isolated from sugary kefir grains capable of polysaccharide production and minicell formation; Pidoux M et al.; Homo- and heterofermentative species of Lactobacillus have been isolated from sugary kefir grains . Most of the homofermentative strains fermented tagatose and aldonitol and presented 48-54% of homology with Lactobacillus paracasei ssp . paracasei NCDO 151 (ex Lactobacillus casei) . The two variants of a hetero-fermentative species, although fermenting arabinose, were related to Lactobacillus hilgardii NCDO 264 (type strain) with 88% of homology . One of them produced polysaccharide from sucrose at pH 4.8 and 30 degrees C; the best glucose conversion into polysaccharide was obtained from 3% of sucrose (81.8%), and the maximum production occurred about 35 hours after the end of the log phase of growth, in MRS sucrose broth . Polysaccharide formation did not occur above 40 degrees C, a temperature at which no growth was observed . The two variants were forming minicells by abnormal divisions.

Rev Infect Dis, 1990 Sep-Oct, 12(5), 856 - 72
Emerging role of lactobacilli in the control and maintenance of the vaginal bacterial microflora; Redondo-Lopez V et al.; The vaginal microflora of healthy asymptomatic women consists of a wide variety (two to five isolates at any one time) of anaerobic and aerobic bacterial genera and species dominated by the facultative, microaerophilic, anaerobic genus Lactobacillus . That the vaginal flora forms part of a dynamically changing ecosystem is evident from the variable prevalence and population levels of each bacterial species detected with repetitive longitudinal sampling, with pregnancy, and with stage in the menstrual cycle . This review emphasizes the role that vaginal lactobacilli may play in control of the vaginal microflora and maintenance of the normal state . Lactobacilli possess many antagonistic properties and produce many metabolites that may be important in maintaining dominance in the vagina . Contradictory data from previous studies regarding the impact of factors such as contraception, catamenial products, and physiologic elements on the vaginal microflora are due in part to poor study design and differences in methodology . Well-designed and controlled investigations with large numbers of individuals in each group are needed, and the limitations of the methodology for such investigations must be considered . Studies of the normal flora, exploring the interaction of lactobacilli and other bacterial species, must be performed before the pathologic processes resulting in vaginitis or systemic sequelae are investigated.

FEMS Microbiol Rev, 1990 Sep, 7(1-2), 43 - 60
In vivo genetic systems in lactic acid bacteria; Gasson MJ; A review of in vivo genetic systems covers the key features of transduction and conjugation but emphasises the intramolecular and intermolecular DNA interactions that are often associated with these processes . As well as the transfer of many lactose plasmids, conjugal transfer of nisin genes and the use of conjugation to construct bacteriophage-resistant dairy starter cultures are discussed . The discovery and characterization of insertion sequences in Lactobacillus and Lactococcus and the exploitation of heterologous conjugation and transposition systems in the lactic acid bacteria are described.

Arch Latinoam Nutr, 1990 Sep, 40(3), 408 - 25
{Preparation of microbial silage from fish of underutilized species}; Ottati M et al.; Fish silage was produced by microbial means from a mixture of several fish species which are not used for human consumption, and form part of the shrimp by-catch . The fish was mixed with a carbohydrate source (molasses) and a starter culture of Lactobacillus plantarum 8014 . The mixture was fermented at 30 +/- 2 degrees C . Several tests were undertaken to determine the optimal conditions and concentration of molasses (5, 10 and 15%) and Lactobacillus (0.5, 1.0, 2.5, 5.0 and 10.0%) . Results indicated that 1% of microorganisms and 15% of molasses were the optimal proportions to produce a stable fish silage . The production process and stability study of fish silage were followed through chemical, physical and microbiological tests . As findings revealed, the first six days of the process are related to acid production, pH reduction and microbial control, while after this period the process is basically related to protein hydrolysis . In addition, sensory tests of flavor and color were performed . The results of this study suggest the feasibility of utilizing this marine resource at present discarded, through a technological scheme, to produce fish silage for animal feed.

FEMS Microbiol Rev, 1990 Sep, 7(1-2), 149 - 63
Antagonistic activities of lactic acid bacteria in food and feed fermentations; Lindgren SE et al.; Many factors contribute to a successful natural fermentation of carbohydrate-rich food and feed products . Metabolic activities of lactic acid bacteria (LAB) play a leading role . Their ability to rapidly produce copious amounts of acidic end products with a concomitant pH reduction is the major factor in these fermentations . Although their specific effects are difficult to quantitate, other LAB metabolic products such as hydrogen peroxide and diacetyl can also contribute to the overall antibiosis and preservative potential of these products . The contribution of bacteriocins is also difficult to evaluate . It is suggested that they may play a role in selecting the microflora which initiates the fermentation . Bacteriocins are believed to be important in the ability of LAB to compete in non-fermentative ecosystems such as the gastrointestinal tract . During the past few decades interest has arisen in the use of the varied antagonistic activities of LAB to extend the shelf-life of protein-rich products such as meats and fish . Recent findings indicate that the newly discovered Lactobacillus reuteri reuterin system may be used for this purpose.

Zh Mikrobiol Epidemiol Immunobiol, 1990 Sep, (9), 3 - 6
{The determination of the antagonistic activity of Solco lactobacteria (Lactobacillus acidophilus Lat 11/83) using gnotobiotic technology}; Popova-Barzashka S et al.; Lactobacillus acidophilus strain Lat 11/83 has been used for the study of its antagonistic activity with respect to pathogenic microorganisms in experiments on conventional germ-free animals . The results of these experiments indicate that the above strain may be recommended as a highly active antagonist for the treatment and prophylaxis of intestinal dysbacteriosis of different etiology.

J Appl Bacteriol, 1990 Sep, 69(3), 321 - 5
Microbiology of 'obiolor': a Nigerian fermented non-alcoholic beverage; Achi OK; Obiolor is an acidic non-alcoholic beverage prepared by fermenting sorghum and millet malts . The traditional process for the production and microbiological characteristics of the beverage were investigated . Bacillus spp., Lactobacillus plantarum and Streptococcus lactis were the associated micro-organisms most actively involved . Yeasts were present in low numbers towards the end of the fermentation . Other micro-organisms isolated did not appear to play a role in the fermentation process . Variations in the important microbial groups involved and their metabolic products were studied . Titratable acidity increased gradually until the end of the fermentation while the total soluble solids and pH declined . Acetobacter spp . were probably responsible for the unacceptability of the product after 24 h.

J Appl Bacteriol, 1990 Sep, 69(3), 302 - 10
Antibacterial activity of lactic acid bacteria isolated from vacuum-packaged meats; Ahn C et al.; Lactic acid bacteria isolated from vacuum-packaged fresh meat stored at 4 degrees C were shown to produce antagonistic substances active against closely related bacteria . Growth medium, pH and growth temperature all affected the production of the inhibitory substances . Ten strains including aciduric Lactobacillus-type organisms, Carnobacterium spp . and Leuconostoc spp . were selected that produced protein-aceous substances that caused inhibition of indicator strains . These were considered to be bacteriocins or bacteriocin-like compounds based on their inactivation with protease, generally narrow spectra of antibacterial activity and bactericidal or bacteriostatic modes of action . Activity was not lost from supernatant fluids as a result of heat treatment at 62 degrees C for 30 min, except for the Leuconostoc strains . Inhibitory spectra of some strains included Enterococcus spp . and Listeria monocytogenes . Some strains were of interest because their inhibitory substances were detected in the supernatant fluid early in the growth cycle . The inhibitory substances differed in characteristics between strains and there is evidence that more than one bacteriocin-like substance may be produced by some strains.

Res Microbiol, 1990 Sep-Oct, 141(7-8), 955 - 62
Oral administration of TNP-Lactobacillus conjugates in mice: a model for evaluation of mucosal and systemic immune responses and memory formation elicited by transformed lactobacilli; Gerritse K et al.; Safe live vector systems are being developed for oral delivery of antigens . A transformation system for indigenous Lactobacillus species of the gastrointestinal tract is described . Model systems were set up to evaluate immune responses . Orally administered trinitrophenylized (TNP) Lactobacillus were examined for their ability to induce immunological memory formation via determination of specific antibody titres in serum . We demonstrate a direct correlation between the level of systemic memory formation, as revealed by specific anti-TNP IgG serum antibodies, and the TNP substitution ratio of the Lactobacillus suspension used for oral priming . The specific IgG anti-TNP serum titres were comparable to or even higher than the titres of parental intraperitoneally primed animals . These results demonstrate the feasibility of using orally administered antigen-Lactobacillus as a future approach to vaccination.

Br J Clin Pract Suppl, 1990 Sep, 71, 65 - 9
Bacterial vaginosis; Sobel JD; In the western world, bacterial vaginosis is now being recognised as the commonest cause of vaginitis . Bacterial vaginosis represents a major disturbance in vaginal microbiology with the massive overgrowth of predominantly anaerobic bacteria normally found in the vagina . Accordingly, high population levels of non-fragilis Bacteroides sp., peptostreptococci, Gardnerella vaginalis and Mobiluncus sp . are found, with a corresponding decline in Lactobacillus sp . Excessive polyamine production by anaerobes is responsible for the offensive vaginal discharge, and G . Vaginalis adherent to epithelial cells produces pathognomonic clue cells, which together with elevated vaginal pH constitute the hallmark of diagnosis . The pathogenesis of bacterial vaginosis remains poorly understood and the role of sexual transmission is controversial . Bacterial vaginosis may cause symptoms but is frequently asymptomatic . It is more than a nuisance vaginal infection in that (a) many patients have recurrent episodes, and (b) it has recently been associated with post-partum and post-operative fever, upper genital tract infection, amnionitis and prematurity . Therapy for symptomatic bacterial vaginosis is currently dominated by metronidazole; however, clindamycin and a host of new agents may enjoy similar success . Women with recurrent bacterial vaginosis constitute a major therapeutic problem, as do pregnant women . The cause of frequently recurring bacterial vaginosis remains obscure . New data are presented here indicating that early recurrences are due to relapse and not reinfection . No evidence has emerged that suggests that relapse is due to antimicrobial resistance.

Indian Heart J, 1990 Sep-Oct, 42(5), 361 - 4
Short term hypolipidemic effects of oral lactobacillus sporogenes therapy in patients with primary dyslipidemias; Mohan JC et al.; Short term hypolipidemic effects of oral Lactobacillus sporogenes (360 million spores/day) were studied in 17 patients (mean age 45.6 years; males 15, females 2) with type II hyperlipidemia in an open label fixed dose trial . Over a period of 3 months, significant reductions were observed in total cholesterol (330 +/- 55 mg% to 226 +/- 46 mg%, p less than 0.001) and LDL-cholesterol (267 +/- 58 mg% to 173 +/- 54 mg%, p less than 0.001) . The HDL-cholesterol was marginally increased (43.6 +/- 7 mg% to 46.8 +/- 8.9 mg%, p less than 0.05) . There was no change in serum triglyceride concentration . Total cholesterol/HDL cholesterol and LDL cholesterol/HDL cholesterol ratios were significantly reduced after treatment (p less than 0.001) . No adverse effect was noted . While the change in serum lipid levels on treatment was consistent with regard to total and LDL-cholesterol, it was not so in case of serum triglycerides and HDL-cholesterol . Oral Lactobacillus sporogenes therapy may prove to be an important hypolipidemic therapy after confirmation in larger trials.

Am J Dent, 1990 Sep, 3 Spec No, S27 - 34
Effect of a triclosan/copolymer/fluoride dentifrice on the oral microflora; Zambon JJ et al.; Eighty-one human subjects completed a double-blind study which examined the effects of a 0.3% triclosan/2% Gantrez copolymer/0.243% sodium fluoride dentifrice on the microflora of supragingival dental plaque . Subjects were divided into an experimental group which performed normal oral hygiene with the triclosan/copolymer/fluoride dentifrice and a control group which also performed normal oral hygiene with the same dentifrice minus the triclosan/copolymer . At baseline, 10 weeks, and 28 weeks, supragingival dental plaque was collected from buccal and lingual surfaces of the four first molar teeth and assayed for: 1) bacterial morphotypes by phase contrast microscopy, 2) Actinobacillus actinomycetemcomitans, Actinomyces species, Bacteroides forsythus, Bacteroides gingivalis, Bacteroides intermedius, Streptococcus mutans, Streptococcus sanguis, and Wolinella recta by immunofluorescence microscopy, and 3) Lactobacillus, yeast, enterics, Staphylococcus, aerobes and anaerobes by bacterial culture . After 28 weeks' use of their respective dentifrices, changes in the supragingival plaque microflora of the subjects were similar between the triclosan/copolymer/fluoride dentifrice group and the control dentifrice group, except for statistically significant reductions in fusiforms, spirochetes and staphylococci and significant increases in S . sanguis in the triclosan/copolymer/fluoride dentifrice group, as compared to the control dentifrice group . The subject population was unusual in the presence of enteric species and anaerobes found in supragingival plaque sites . This study indicates that the use of a dentifrice containing 0.3% triclosan and 2% Gantrez copolymer over an extended period of time (28 weeks) does not result in shifts in the microflora of supragingival plaque favoring the growth of either opportunistic or pathogenic bacterial species.

Eur J Biochem, 1990 Aug 17, 191(3), 659 - 68
The 1H-NMR assignments of the aromatic resonances in complexes of Lactobacillus casei dihydrofolate reductase and the origins of their chemical shifts; Birdsall B et al.; All the aromatic proton resonances in the 500-MHz NMR spectra of Lactobacillus casei dihydrofolate reductase have been assigned for several of its complexes with inhibitors . For the complexes with methotrexate and trimethoprim this was achieved by using a combination of NMR techniques in conjunction with a selectively deuterated protein designed to simplify the spectra such that nuclear Overhauser effect (NOE) connections could be detected with greater ease and certainty . By correlating these NOE data with crystal structure data on related complexes it was possible to assign all the aromatic resonances and to extend these assignments to spectra of other complexes of dihydrofolate reductase . The conformation-dependent chemical shifts observed for many of the resonances could be explained qualitatively, but not quantitatively, in terms of ring-current shifts . The discrepancies between calculated ring-current shifts and the observed conformation-dependent shifts could not in general be accounted for satisfactorily in terms of carbonyl-group anisotropic shielding contributions calculated using presently available models . In the case of the H delta 1, delta 2 protons of Phe30 some of the discrepancy probably results from a difference in the conformation of the Phe ring between the solution and crystal states.

Scand J Dent Res, 1990 Aug, 98(4), 305 - 12
Comparative study on mineralization-related intraoral parameters in periodontitis-affected and periodontitis-free adults; Sewon L et al.; The parameters related to an intraoral mineralization tendency in periodontitis-affected (P+) and periodontitis-free (P-) study subjects (16 adults, 46-74 yr, matched for sex and age) were compared . For this purpose the calcium (Ca) and phosphate (P) concentration of both plaque and saliva, resting pH and the acidogenic response of interdental plaque, plaque wet weight, salivary flow rate, buffering capacity and sucrase activity, interdental plaque, plaque S . mutans levels as well as salivary lactobacilli and yeast levels were estimated . Plaque Ca (micrograms/mg protein, P less than 0.025) and P (micrograms/mg protein, P less than 0.05), saliva Ca (micrograms/ml, P less than 0.005) and the saliva Ca:P ratio (P less than 0.005) were higher in the P+ than in the P- group . The resting pH values were higher (P less than 0.025) and the acidogenic response of the interdental plaque was lower (P less than 0.025) in the P+ group than in the P- group . The P+ group had lower S . mutans levels in saliva and interdental plaque . No differences were found in the wet weight of plaque and in the flow rate, buffering capacity or sucrase activity of saliva between the groups . The findings of the mineralization-related parameters in the two "extreme" groups of periodontal status suggest a higher intraoral mineralization tendency in periodontitis-affected persons than in periodontitis-free subjects . Ca and P accumulation of supragingival plaque seem to be connected with low acidogenicity of plaque and high salivary Ca concentration.

J Dent Res, 1990 Aug, 69(8), 1463 - 8
Association of the microbial flora of dental plaque and saliva with human root-surface caries; Van Houte J et al.; Dental plaque was obtained from one or two sound root surfaces of subjects with different degrees of root-surface caries experience . From subjects with root-surface caries, plaque samples were also obtained from either one incipient or one more advanced lesion . Proportions of the total flora were determined for total streptococci and different streptococcal species, total and different Actinomyces species, and lactobacilli . A sample of saliva was obtained from about one-third of the subjects for determination of the concentrations of mutans streptococci and lactobacilli . The main observations were: (1) Subjects without root-surface caries or restorations (group I), as compared with subjects with root-surface caries with or without restorations (group II), were characterized by having a lower prevalence and proportion of mutans streptococci and a higher prevalence and proportion of A . naeslundii in plaque on sound root surfaces; (2) subjects in group I also tended to have a lower salivary concentration of mutans streptococci and lactobacilli than subjects in group II; (3) dental plaque on sound surfaces in group II subjects contained a lower proportion of mutans streptococci than plaque associated with incipient or advanced lesions; and (4) the prevalence and proportion of lactobacilli in plaque associated with sound as well as carious root surfaces were very low . The data reinforce findings from other studies and indicate that, as for coronal caries, the plaque and saliva populations of mutans streptococci specifically are correlated positively with the presence of root-surface caries.

J Bacteriol, 1990 Aug, 172(8), 4171 - 7
Characterization and purification of bile salt hydrolase from Lactobacillus sp . strain 100-100; Lundeen SG et al.; We have characterized and purified the bile salt hydrolase from Lactobacillus sp . strain 100-100 . Bile salt hydrolase from cells of the strain was purified with column and high-performance liquid chromatography . The activity was assayed in whole cells and cell-free extracts with either a radiochemical assay involving {14C}taurocholic acid or a nonradioactive assay involving trinitrobenzene sulfonate . The activity was detectable only in stationary-phase cells . Within 20 min after conjugated bile acids were added to stationary-phase cultures of strain 100-100, the activity in whole cells increased to levels three- to fivefold higher than in cells from cultures grown in medium free of bile salts . In cell-free extracts, however, the activity was about equal, 1.41 and 1.53 mumol/min per mg of protein, respectively, whether or not the cells have been grown with bile salts present . When supernatant solutions from cultures grown in medium containing taurocholic acid were used to suspend cells grown in medium free of the bile salt, the bile salt hydrolase activity detected in whole cells increased two- to threefold . Two forms of the hydrolase were purified from the cells and designated hydrolases A and B . They eluted from anion-exchange high-performance liquid chromatography in two sets of fractions, A at 0.15 M NaCl and B at 0.18 M NaCl . Their apparent molecular weights in nondenaturing polyacrylamide gel electrophoresis were 115,000 and 105,000, respectively . However, discrepancies existed in the apparent molecular weights and number of peptides detected in sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the two forms . Both had similar substrate specificities, highest on taurodeoxycholic and glycocholic acid, and pH optima between 3.8 and 4.5 . The kinetic properties were also similar, with Vmaxs of 17 and 53 micromoles/min per mg of protein and Kms of 0.76 and 0.95 mM taurocholic acid for A and B, respectively . Therefore, whether the enzyme exists in two forms in the cells remains to be determined.

Acta Odontol Scand, 1990 Aug, 48(4), 217 - 22
Effect of culture medium on acid production from sorbitol by oral bacteria; Kalfas S et al.; The fermentation of sorbitol or glucose and the acid production by strains belonging to the genera Actinomyces, Lactobacillus, and Streptococcus isolated from the predominant sorbitol-fermenting human dental plaque flora were studied in cultures in complex or defined bacteriologic broths and in saliva-based broth . The growth yields of Lactobacillus and Streptococcus in the saliva-based media and of Actinomyces in the defined broth were poor . Addition of fermentable carbohydrate to the saliva-based broth favored the growth of Streptococcus and Lactobacillus but not that of Actinomyces . The results showed obvious differences in the capacity of oral bacteria to ferment sorbitol between cultures in saliva-based and bacteriologic broths . Lactobacillus failed to utilize sorbitol when saliva was the only source of nutrients . Lower proportions of lactic and formic acids were formed from sorbitol by Actinomyces and Lactobacillus in the saliva-based than in the bacteriologic media . The findings illustrate some mechanisms possibly involved in the interactions between sorbitol and dental plaque flora.

J Appl Bacteriol, 1990 Jul, 69(1), 80 - 5
Iron complexation as a tool to direct mixed clostridia-lactobacilli fermentations; Bruyneel B et al.; Iron complexation was investigated as a possible tool to give lactobacilli a competitive advantage over clostridia . The iron complexing substance tested, i.e . 2,2'-dipyridyl, was not toxic itself for clostridia, but its addition to a mixed culture of lactobacilli and clostridia resulted in a strong ecological advantage of the lactobacilli.

Int J Syst Bacteriol, 1990 Jul, 40(3), 302 - 4
Lactobacillus intestinalis (ex Hemme 1974) sp . nov., nom . rev., isolated from the intestines of mice and rats; Fujisawa T et al.; The genetic and phenotypic properties of 10 strains identified as Lactobacillus intestinalis sp . nov . were examined . These strains constitute a distinct species which can be differentiated from all of the previously described homofermentative species in the genus Lactobacillus by their carbohydrate fermentation pattern . The guanine-plus-cytosine contents of their DNAs are 33 to 35 mol% . DNAs from 10 other Lactobacillus species did not exhibit significant levels of relatedness to representative strains of the new species . The name Lactobacillus intestinalis (ex Hemme) sp . nov., nom . rev . is proposed for these isolates, and strain Th4 (= ATCC 49335 = JCM 7548) is the type strain.

Appl Environ Microbiol, 1990 Jul, 56(7), 2029 - 35
Isolation of a replication region of a large lactococcal plasmid and use in cloning of a nisin resistance determinant; von Wright A et al.; The replication region of a 28-kilobase-pair (kbp) cryptic plasmid from Lactococcus lactis subsp . lactis biovar diacetylactis SSD207 was cloned in L . lactis subsp . lactis MG1614 by using the chloramphenicol resistance gene from the streptococcal plasmid pGB301 as a selectable marker . The resulting 8.1-kbp plasmid, designated pVS34, was characterized further with respect to host range, potential cloning sites, and location of replication gene(s) . In addition to lactococci, pVS34 transformed Lactobacillus plantarum and, at a very low frequency, Staphylococcus aureus but not Escherichia coli or Bacillus subtilis . The 4.1-kbp ClaI fragment representing lactococcal DNA in pVS34 contained unique restriction sites for HindIII, EcoRI, XhoII, and HpaII, of which the last three could be used for molecular cloning . A region necessary for replication was located within a 2.5-kbp fragment flanked by the EcoRI and ClaI restriction sites . A 3.8-kbp EcoRI fragment derived from a nisin resistance plasmid, pSF01, was cloned into the EcoRI site of pVS34 to obtain a nisin-chloramphenicol double-resistance plasmid, pVS39 . From this plasmid, the streptococcal chloramphenicol resistance region was subsequently eliminated . The resulting plasmid, pVS40, contains only lactococcal DNA . Potential uses for this type of a nisin resistance plasmid are discussed.

J Clin Microbiol, 1990 Jul, 28(7), 1506 - 8
Reproducibility of interpretation of Gram-stained vaginal smears for the diagnosis of bacterial vaginosis; Mazzulli T et al.; In the diagnostic microbiology laboratory, interpretation of Gram-stained slides of vaginal swab specimens is used to support the clinical diagnosis of bacterial vaginosis . The reproducibility with which technologists interpret these Gram-stained slides was evaluated by presenting, in coded fashion, 80 original slides and 80 duplicate slides of vaginal swab specimens to three technologists . They each interpreted the original slide twice and the duplicate slide from the same specimen once . Intraobserver and interobserver agreement was assessed by use of the weighted kappa statistic . Semiquantitation of Lactobacillus and Gardnerella morphotypes and a diagnosis of bacterial vaginosis showed the greatest intraobserver agreement, with kappa values ranging from 0.772 to 1.000 . Interobserver agreement was also high for rating Lactobacillus morphotypes and clue cells (kappa values between 0.735 and 0.869) but decreased slightly for Gardnerella morphotypes and a diagnosis of bacterial vaginosis (kappa values between 0.656 and 0.800) . These results indicate that there is good agreement for the interpretation of Gram-stained slides of vaginal swab specimens and that this method alone, without culture, can be used reliably to support the clinical diagnosis of bacterial vaginosis.

Zh Mikrobiol Epidemiol Immunobiol, 1990 Jul, (7), 17 - 9
{The correction of dysbiotic disorders of the vaginal microflora by using a preparation made from highly adhesive lactobacteria}; Korshunov VM et al.; The effectiveness of a new bacterial preparation obtained from highly adhesive lactobacteria and intended for the correction of dysbiotic disturbances of vaginal microflora was studied in the treatment of 60 pregnant women with dysbacteriosis of the maternal passages . 30 pregnant women were simultaneously treated by the vaginal application of Lactobacterin . The study showed that the use of the preparation of highly adhesive lactobacteria caused the pronounced and stable correction of the microflora of the maternal passages . This correction was manifested by the domination of lactic acid bacterial flora and a decrease in the number of opportunistic microorganisms.

Plant Foods Hum Nutr, 1990 Jul, 40(3), 167 - 73
Fermentation of pearl millet flour with yeasts and lactobacilli: in vitro digestibility and utilisation of fermented flour for weaning mixtures; Khetarpaul N et al.; Single as well as mixed culture fermentation by yeasts (S . diastaticus; S . cerevistiae) and lactobacilli (L . brevis; L . fermentum) at 30 degrees C for 72 h improved the starch and protein digestibility (in vitro) of pearl millet flour significantly . The flour fermented by Saccharomyces diastaticus, a starch hydrolysing yeast, had the highest starch digestibility whereas fermentation by Saccharomyces cerevisiae enhanced the in vitro protein digestibility of the flour significantly . Weaning mixtures prepared from the fermented flour were also found to be organoleptically acceptable.

Clin Microbiol Rev, 1990 Jul, 3(3), 280 - 91
Resistance to vancomycin and teicoplanin: an emerging clinical problem; Johnson AP et al.; Vancomycin and teicoplanin are glycopeptides active against a wide range of gram-positive bacteria . For 30 years following the discovery of vancomycin in 1956, vancomycin resistance was not detected among normally susceptible bacteria recovered from human specimens . Since 1986, however, bacteria resistant to vancomycin or teicoplanin or both have been described . Strains of the genera Leuconostoc, Lactobacillus, Pediococcus, and Erysipelothrix seem inherently resistant to glycopeptides . Species and strains of enterococci and coagulase-negative staphylococci appear to have acquired or developed resistance . There are at least two categories of glycopeptide resistance among enterococci, characterized by either high-level resistance to vancomycin (MIC, greater than or equal to 64 mg/liter) and teicoplanin (MIC, greater than or equal to 8 mg/liter) or lower-level vancomycin resistance (MIC, 32 to 64 mg/liter) and teicoplanin susceptibility (MIC, less than or equal to 1 mg/liter) . The two categories appear to have similar resistance mechanisms, although genetic and biochemical studies indicate that they have arisen independently . Among coagulase-negative staphylococci, strains for which vancomycin MICs are up to 20 mg/liter or teicoplanin MICs are 16 to 32 mg/liter have been reported, but cross-resistance between these glycopeptides varies . The selective advantage accorded to glycopeptide-resistant bacteria and the observation that high-level resistance in enterococci is transferable suggest that such resistance may be expected to increase in incidence . Clinicians and microbiologists need to be aware of this emerging problem.

Rev Fac Odontol Univ Chile, 1990 Jul-Dec, 8(2), 17 - 25
{Antimicrobial activity of orthodontic band cements}; Pavic J et al.; The prevalence of enamel decalcification and caries beneath orthodontic bands, has indicated the need for a new enamel binding adhesive orthodontic cement . The purpose of this study was to evaluate the antimicrobial activity, in vitro, on Streptococcus mutans and Lactobacillus, acidophillus, of three materials used to cements the orthodontic bands . The cements studied were: Zinc phosphate cement, Glass-ionomer cement, and Policarboxylate cement . Thirty petri plates were seeded with S . mutans, and thirty with L . acidophillus; on each plate three pellet were placed, one of each cement studied . Petri plates were incubated under microaerophilic conditions at 37 C, and checked at 72 hrs . for Streptococcus, mutans, and four days for Lactobacillus acidophillus to evaluate the inhibition zone . The results were tabulated for each material . It was demonstrated that exists important variations in the antimicrobial properties of the materials studied, as in the microbial sensitivity to these cements.

Pract Odontol, 1990 Jul, 11(7), 37 - 9, 42-3, 45-6
{Prevention of caries with lactobacillus (final results of a clinical trial on dental caries with killed lactobacillus {streptococcus and lactobacillus} given orally)}; Bayona Gonzalez A et al.; Caries prevention with lactic bacteria . (Final results of a dental caries clinical trial using heat killed lactic bacteria {streptococci and lactobacilli} orally.) The results of a dental caries clinical trial in 245 seven-year-old children are reported . Chewable tablets of two different types were prepared: A) Containing pyridoxine (Vit . B6) and heat killed lactic bacteria . B) Placebo tablets with pyridoxine only . They were randomly given once a week for 16 weeks to experimental and control groups respectively . Four evaluation surveys were conducted during 24 months of follow up, using the "Decay, Missing, Filled, Surfaces" index (DMFS) for the clinical evaluation of the permanent teeth . A consistent reduction in the incidence of dental caries in the experimental group was observed in all 4 surveys . After 2 years of follow up a 42% reduction in the incidence rate of dental caries was observed in the experimental group compared to the control group . Summary tables and discussion of the clinical evaluation surveys are given . The potential use of these clinical findings as support for a future dental caries vaccine evaluation project is proposed.

Zh Mikrobiol Epidemiol Immunobiol, 1990 Jul, (7), 14 - 7
{The effect of "Solco" lactobacteria (Lactobacillus acidophilus) on the survival and microflora of mice with a Salmonella infection}; Popova-Barzashka S et al.; The Solco lactobacterial strain L . acidophilus Lat 11/83 has been used for the normalization of intestinal microflora in experimental post-infectious intestinal dysbacteriosis in mice . The results of experiments indicate that the intragastric administration of live Solco lactobacteria contributes to an increase in the survival rate of infected animals and the normalization of their gastrointestinal microflora . This strain may be used as a bacterial preparation for the regulation of intestinal microbiocenosis.

Kansenshogaku Zasshi, 1990 Jul, 64(7), 781 - 6
{The antitumor activity of Lactobacillus casei--the direct effects of L . casei to human tumor cell lines}; Katayama Y; The effects of somatic components of Lactobacillus casei (L . casei) were studied on cell growth in vitro . L . casei was able to suppress the growth of MT-2, MT-4 cells from adult T-cell leukemia, Molt-4 cells from acute lymphoblastic leukemia and U-937 cells from promonocytic leukemia . This effect was obviously different from the cytotoxicity of Vinbrastin, an anti-cancer drug . Flow cytometric experiments employing BrdU-anti BrdU antibody demonstrated an increase of cells in G1 + G0 phases (pre-DNA synthesis phases) by the treatment of L . casei, therefore L . casei maybe acts as a low grade inhibitor of the protein synthesis . PC-treated L . casei had no more inhibition on cell growth than the non-treated one.

Int J Syst Bacteriol, 1990 Jul, 40(3), 224 - 30
16S rRNA sequence determination for members of the genus Carnobacterium and related lactic acid bacteria and description of Vagococcus salmoninarum sp . nov; Wallbanks S et al.; The phylogenetic interrelationships of members of the genus Carnobacterium and some atypical lactobacilli isolated from diseased salmonid fish were investigated by using reverse transcriptase sequencing of 16S rRNA . The four species Carnobacterium piscicola, Carnobacterium divergens, Carnobacterium gallinarum, and Carnobacterium mobile exhibited a high degree of sequence similarity with each other (ca . 96 to 98%) and formed a phylogenetically coherent group that was quite distinct from all other lactic acid bacteria . The sequence data clearly demonstrated that carnobacteria are phylogenetically closer to the genera Enterococcus and Vagococcus than to members of the genus Lactobacillus . The strains from fish were found to be phylogenetically related to the genus Vagococcus and represent a new species, Vagococcus salmoninarum . The type strain of Vagococcus salmoninarum is strain NCFB 2777.

FEMS Microbiol Lett, 1990 Jun 15, 58(1), 73 - 83
A phylogenetic analysis of the genus Leuconostoc based on reverse transcriptase sequencing of 16 S rRNA; Martinez-Murcia AJ et al.; The phylogenetic interrelationships of members of the genus Leuconostoc and some heterofermentative lactobacilli, which phenotypically resemble leuconostocs, were investigated by comparative analysis of their 16 S rRNA sequences . The six species, Leuconostoc mesenteroides, Leu . carnosum, Leu . citreum, Leu . gelidum, Leu . lactis and Leu . pseudomesenteroides exhibited a high degree of sequence similarity with each other and formed a phylogenetically coherent group, quite separate from all other lactic acid bacteria investigated . The species Leu . paramesenteroides was found to be phylogenetically distinct from the Leu . mesenteroides group of species and formed a natural grouping with the heterofermentative lactobacilli, Lb . confusus, Lb . kandleri, Lb . minor and Lb . viridescens . The rRNA sequence of the acidophilic species, Leu . oenos, displayed exceptionally low levels of homology with all of the other taxa examined . The 16 S sequence of Leu . oenos showed major nucleotide differences in relatively highly conserved positions of the molecule indicating this species is phylogenetically distinct and warrants a separate genus.

J Clin Microbiol, 1990 Jun, 28(6), 1348 - 55
Clinical and microbiologic characteristics of pediococci; Riebel WJ et al.; Over a 43-month period, 23 separate isolates of nonenterococcal alpha- and nonhemolytic streptococci were reported by our clinical microbiology laboratory to be resistant to vancomycin . This constituted 0.32% of nonenterococcal alpha- and nonhemolytic streptococci reported and 4.4% of such streptococci upon which susceptibility testing was performed . Of 13 isolates which were available for further study, all were highly resistant to vancomycin (MIC greater than or equal to 1,024 micrograms/ml), but none were actually streptococci . Three were clearly gram-positive rods by Gram stain and were found to be homofermentative lactobacilli . Two strains with elongated gram-positive cocci from colonies on agar showed small gram-positive rods when grown in thioglycolate broth and were physiologically identified as Lactobacillus confusus . Two isolates with lenticular gram-positive cocci appeared to be Leuconostoc mesenteroides subsp . mesenteroides . Six gram-positive isolates with round cells from growth on agar and from broth were arranged in tetrads in broth and closely resembled Pediococcus acidilactici . Twelve additional strains of pediococci that were not of human origin were also found to be highly resistant to vancomycin . These findings confirm published reports of clinical isolation of organisms resembling pediococci and suggest that clinically isolated, vancomycin-resistant bacteria which superficially resemble streptococci are probably other lactic acid bacteria.

Acta Odontol Scand, 1990 Jun, 48(3), 183 - 7
Sucrase activity in relation to other salivary factors and DMFS values of dental students; Karjalainen S et al.; Samples of stimulated whole saliva were collected from 176 dental students, and their teeth were examined both clinically and radiographically . Salivary flow; buffering capacity; numbers of lactobacilli, yeasts, and Streptococcus mutans; and DMFS and DS values were correlated to sucrase activity . The high flow-rate group had a lower (p = 0.0201*) sucrase activity than the low flow-rate group . The proportion of high (greater than or equal to 10 mumol/min x mg x 10(-3} sucrase activities among the highest density category of lactobacilli was 67%, whereas the corresponding proportion in the whole material was only 28% . Men had significantly (p = 0.0169*) higher sucrase activities than women . The other variables measured did not seem to have any significant effect on the sucrase activity values . In addition to sucrose consumption, other factors like the rate of salivary flow and the density of lactobacilli seem to influence the level of salivary sucrase activity.

Community Dent Oral Epidemiol, 1990 Jun, 18(3), 149 - 52
Longitudinal study of caries and cariogenic bacteria in an elderly disabled population; MacEntee MI et al.; A 2-yr longitudinal study was conducted among elderly disabled residents of a longterm care facility . Each of the 50 subjects examined at the beginning of the study had a mean of 14 teeth, with a mean of 6 carious and 6 restored teeth, per person . Most of the subjects had very poor oral hygiene, and 26 of them had dental plaque that produced cultures of mutans streptococci and lactobacilli in excess of 10(5) CFU/ml . At the end of the first year, 40 subjects were examined again and, apart from a decrease in the mean number of carious root lesions per person, there was very little change in their dental or microbial status . Although only 18 subjects were available at the end of the second year, they presented with fewer carious lesions after 2 yr . The reduction in caries appeared to result from the remineralization of tooth structure, but new lesions did appear in 33% of the 1-yr group, and in 78% of the 2-yr group . This dynamic environment around the teeth produced a mean net incidence of one lesion in the first year, and three lesions over 2 yr . There was a significant (P less than 0.05) association between large (greater than 10(5) CFU/ml) numbers of mutans streptococci and the development of new lesions, but there was no association between the dental status of the subjects and the dental treatment they received . Overall, the results indicate that caries is not rampant in this population.

Community Dent Oral Epidemiol, 1990 Jun, 18(3), 120 - 5
Caries prevalence and microbiological and salivary caries activity tests in Scottish adolescents; Russell JI et al.; Salivary and microbiological caries activity tests were investigated on three occasions in a group of 372 Scottish adolescents . Counts of lactobacilli, mutans streptococci, and candida were consistently and significantly associated with caries prevalence, as either DS or DMFS score, and buffering capacity was consistently inversely related to DMFS score . However, veillonella counts and salivary flow rate were not correlated with caries prevalence . Significant improvements in the associations were obtained when the results of more than one test were included using stepwise regression analysis . On an individual basis, at most, stepwise discriminant analysis identified the DMFS group correctly in 49% of all subjects, and the DS group in 47%.

Scand J Dent Res, 1990 Jun, 98(3), 197 - 210
Salivary conditions and cariogenic microorganisms in 55, 65, and 75-year-old Swedish individuals; Fure S et al.; Secretion rate, buffer capacity, and cariogenic microorganisms of resting and stimulated whole saliva were examined in 208 55-, 65-, and 75-yr-old Swedes . The secretion rate for both resting and stimulated saliva decreased with age . When the use of drugs was taken into account the difference in terms of age group was significant for resting saliva alone (P less than 0.01) . In 22% the resting saliva was less than 0.1 ml/min, and in 5% the stimulated saliva was less than 0.7 ml/min . Persons with subjective dryness in the mouth had a lower salivary flow . Men had higher secretion rates than women irrespective of medication (P less than 0.05) . The buffer capacity was strongly correlated to the secretion rate of both resting and stimulated saliva (r = 0.39 and r = 0.44, respectively) . The number of mutans streptococci and lactobacilli increased with age, although significant in terms of age group for lactobacilli alone (P less than 0.05) . The number of these microorganisms was lower in resting saliva than in stimulated saliva (P less than 0.0001) . Individuals harboring both Streptococcus mutans and Streptococcus sobrinus had higher values of mutans streptococci in resting and stimulated saliva than those harboring only S . mutans (P less than 0.001) . Actinomyces viscosus and Actinomyces naeslundii comprised greater than or equal to 1% of the total CFU in 89% of the plaque samples . The corresponding figures for lactobacilli and mutans streptococci were 6% and 38%, respectively.

Infect Immun, 1990 Jun, 58(6), 1628 - 33
Microflora associated with experimental root surface caries in humans; Nyvad B et al.; This study describes the microflora from actively progressing root surface caries lesions, in which mineral loss had been determined by quantitative microradiography . The caries lesions were produced experimentally in root surface specimens from human molars inserted in lower partial dentures carried for 3 months by six elderly individuals . A total of 780 bacterial isolates were identified from 13 plaque samples, collected with a punch technique, and six dentin samples . The composition of the microflora showed distinct individual differences . The microflora from plaque samples associated with the highest mineral loss was dominated by either Actinomyces viscosus or a combination of mutans streptococci (serotypes c, d, and f) and Lactobacillus species (L . casei and L . brevis) . Plaque from root surfaces with less pronounced mineral loss harbored a more complex microflora comprising gram-positive rods, mutans streptococci, Streptococcus mitis biovar 1, Veillonella spp., gram-negative rods, and low numbers of lactobacilli . In the latter samples, individual variations in the proportions of mutans streptococci (serotypes c, d, and g), Actinomyces species (A . viscosus and A . naeslundii), and Veillonella parvula biotypes were observed . These findings suggest that certain species or combinations of species are more cariogenic than others and that dominance of single acidogenic species in particular is conducive to high caries activity.

FEMS Microbiol Lett, 1990 Jun 1, 57(3), 289 - 92
Expression of the lipase gene from Staphylococcus hyicus in Lactobacillus curvatus Lc2-c; Vogel RF et al.; An electroporation based transformation system was developed for Lactobacillus curvatus Lc2-c, a plasmid cured potential raw sausage starter . It was transformed with plasmid pLipPS1, a staphylococcal vector plasmid containing the lipase gene from Staphylococcus hyicus . Transformants exhibited high lipase activity, whereas the wild type strain was lipase negative . The production and release into the medium of a heterologous lipase by a Lactobacillus could be shown for the first time.

FEMS Microbiol Lett, 1990 Jun 1, 57(3), 233 - 8
Cloning and structure of the pyrE gene of Lactobacillus plantarum CCM 1904; Bouia A et al.; The pyrE gene of Lactobacillus plantarum CCM 1904, coding for the orotate phosphoribosyl transferase involved in the pyrimidine biosynthetic pathway, was cloned in Escherichia coli and sequenced . The predicted polypeptide sequence extending over 212 amino acids (MW 22,690) was compared to those of E . coli and to those of lower eukaryotes (Saccharomyces cerevisiae, Podospora anserina, Sordaria macrospora, Dictyostelium discoideum) . Important conserved stretches were revealed, implying that these proteins are closely related.

Community Dent Oral Epidemiol, 1990 Jun, 18(3), 126 - 30
Oral health of workers in the modern Finnish confectionery industry; Masalin K et al.; The association between type of work and dental findings and the relevance of sugar dust as an occupational hazard to dental health was studied in workers producing sweets, biscuits, and bakery products, and in controls in a work environment not concerned with sugar . 298 employees, 42 +/- 11 yr of age, were investigated clinically and by means of chemical and microbiological tests of their saliva . Mean total time of work on the production line in question was 10 +/- 8.5 yr . Periodontal treatment needs increased similarly with increasing age in all subgroups . Subjects concerned with biscuit production had significantly higher DMFS values than subjects in the other groups . They also had significantly higher numbers of untreated cavities: 79.6% compared with 54.7% in those making sweets, 48.3% in bakery workers, and 62.6% in the controls not exposed to sugar . High levels of lactobacilli and Streptococcus mutans were found equally in all subgroups . Because work hygiene measurements have previously shown that sugar and flour dust concentrations were below accepted limits in the confectionery factory studied, the results do not seem to support the hypothesis that airborne sugar is an occupational dental health hazard . Some other factors need to be accounted for to explain the findings.

J Bacteriol, 1990 Jun, 172(6), 3089 - 99
Lactobacillus hilgardii plasmid pLAB1000 consists of two functional cassettes commonly found in other gram-positive organisms; Josson K et al.; A Lactobacillus hilgardii plasmid, pLAB1000, was studied to understand the organization of autonomous replicons from lactobacilli . Two cassettes could be identified . First, the replication region consisted of a sequence coding for a replication protein (Rep) and its corresponding target site, similar to those from plasmids pUB110, pC194 (Staphylococcus aureus), pFTB14, pBAA1 (Bacillus sp.), and pLP1 (Lactobacillus sp.) . Sequence analysis indicated the possible synthesis of an antisense RNA that might regulate Rep production . The results also suggested that pLAB1000 replicates via a single-stranded DNA intermediate, and a putative lagging-strand initiation site was found that had similarities to those of alpha 3, St-1, and G4 isometric bacteriophages . The second cassette of pLAB1000 consisted of a sequence coding for a putative mobilization protein (Mob) and its corresponding RSA site . This cassette was similar to those found in pT181, pUB110, pE194 (S . aureus), and pG12 (Bacillus sp.), and it was found to be conserved among different Lactobacillus plasmid replicons . The origin and evolution of these functional cassettes are also discussed.

Pract Odontol, 1990 Jun, 11(6), 41 - 7
Final results of a dental caries clinical trial using heat killed lactic bacteria (Streptococci and Lactobacilli) orally; Bayona-Gonzalez A et al.; The results of a dental caries clinical trial in 245 seven-year-old children are reported . Chewable tablets of two different types were prepared: A) Containing pyridoxine (Vit . B6) and heat-killed lactic bacteria . B) Placebo tablets with pyridoxine only . They were randomly given once a week for 16 weeks to experimental and control groups respectively . Four evaluation surveys were conducted during 24 months of follow up, using the "Decay, Missing, Filled, Surfaces" index (DMFS) for the clinical evaluation of the permanent teeth . A consistent reduction in the incidence of dental caries in the experimental group was observed in all 4 surveys . After 2 years of follow up a 42% reduction in the incidence rate of dental caries was observed in the experimental group compared to the control group . Summary tables and discussion of the clinical evaluation surveys are given . The potential use of these clinical findings as support for a future dental caries vaccine evaluation project is proposed.

Rev Dent Chile, 1990 Jun-Aug, 81(2), 60 - 4
{Analysis of the in vitro antibacterial action of a fluoridated amalgam}; Valenzuela V et al.; To a conventional silver amalgam alloy was added 1% of stanous fluoride, to prove in vitro, if it presents any antibacteria actions against S . mutans and Lactobacillus acidophilus . Thirteen Petri plate were seeded with S . mutans and 12 Petri plate with Lactobacillus, in both cases, was disposited fluoride containing amalgam and conventional amalgam . The average of inhibition signs in the Petri plates with S . mutans was 1.7 mm in the Petri plates with Lactobacillus the average was 2.4 mm . Is demonstrated that the fluoride containing amalgam has in vitro antibacteria action in comparison with conventional amalgam, that has none.

Int J Food Microbiol, 1990 May, 10(3-4), 323 - 9
Heme-dependent and heme-independent nitrite reduction by lactic acid bacteria results in different N-containing products; Wolf G et al.; Seventy strains of lactic acid bacteria were investigated for nitrite reductase activity . Two types of this activity were detected . Type I was found in Lactobacillus plantarum, L . pentosus and Pediococcus pentosaceus . This activity is heme-dependent with ammonia as the sole product . Type II mechanism is heme-independent and reduces nitrite to NO and N2O.

Int J Food Microbiol, 1990 May, 10(3-4), 245 - 53
Lactic acid and pH as indicators of spoilage for vacuum-packed cooked ring sausages; Korkeala H et al.; Lactic acid production and pH changes of 206 vacuum-packed cooked ring sausages stored at 2, 4 and 12 degrees C from 21 different production runs were monitored as a function of time and of microbial growth . The total lactic acid concentrations and pH values were first at a constant level, starting to increase sharply after the lactobacilli count reached about 5 x 10(7) or 6 x 10(7) cfu/g, respectively . The lactic acid and pH changes as a function of the lactobacilli count were similar at 4 and 12 degrees C . The sharp increase at high lactobacilli counts was observed in both L-lactic acid and D-lactic acid . The variation was lesser and the increase greater in D-lactic acid formation than in L-lactic acid . Above a level of 3-4 mg lactic acid/g most of the samples were deemed unfit . The pH started to decrease from a level of approx . 6.3; below 5.8-5.9 the samples were deemed unfit . The lowest pH value observed was 4.58 . Both a high lactic acid content and a low pH indicated that the sausage was spoiled . These changes, however, took place at later stages of storage, and do not give information about the early phase of spoilage.

Nippon Shokakibyo Gakkai Zasshi, 1990 May, 87(5), 1168 - 74
{Clinical evaluation of serum biotin levels and biotinidase activities in patients with various liver diseases}; Nagamine T et al.; In order to evaluate the clinical significance of serum biotin and biotinidase in liver disease, serum biotin levels and biotinidase activities were determined in 83 patients with various liver diseases and 10 healthy controls . Serum biotin levels and biotinidase activities were determined by a simplified lactobacillus plantarum bioassay and liquid chromatography with fluorimetric detection respectively . Serum biotin levels in decompensated liver cirrhosis, hepatoma and fulminant hepatitis were found to be significant low compared with healthy controls, while it was significant high in autoimmune hepatitis . There was no significant difference between serum biotin levels in the other liver diseases and healthy controls . In various liver diseases except for both acute hepatitis and alcoholic liver disease biotinidase activities were significantly reduced than in healthy controls . Serum biotinidase activities were correlated with serum albumin, prothrombin time, ChE and total cholesterol respectively, suggesting that biotinidase activities may reflect the degree of liver damage . These results seem that biotin deficiency may occur in some cases of severe liver diseases.

Anal Biochem, 1990 May 1, 186(2), 202 - 8
Development of a trichloroacetic acid precipitation assay for covalent adducts of thymidylate synthase; Cisneros RJ et al.; The use of trichloroacetic acid as a protein precipitant and denaturant in the quantitative measurement of covalent complexes of thymidylate synthase is described . Enzyme inactivated with N{3H}ethylmaleimide and inhibitory ternary complex (formed with native enzyme, 5-{6-3H}fluoro-2'-deoxyuridylate, and methylenetetrahydrofolate) served as reagents which were used to establish the conditions under which trichloroacetic acid precipitation, washing, and solubilization steps provided quantitative results . The ternary complex formed by dihydrofolate reductase with {3H}methotrexate and NADPH was used as a control to assess whether tight, but noncovalent, enzyme:ligand complexes survived trichloroacetic acid precipitation . The fact that no counts above background were detected in the pellet of precipitated protein demonstrated that the noncovalent complexes were completely dissociated by this treatment . The dynamic range of linear response for the inhibitory ternary complex of thymidylate synthase spanned five orders of magnitude, and the assay detected levels of enzyme as low as 10 fmol, a value which was essentially limited by the specific radioactivity of 5-{6-3H}fluoro-2'-deoxyuridylate . The ability of the enzyme to bind 5-{6-3H}fluoro-2'-deoxyuridylate specifically, as measured by the trichloroacetic acid assay, generated a specific binding value of 13.4 nmol of enzyme/mg protein (assuming a binding ratio of 1.5 for the inhibitory ternary complex) . Specific binding values were compared to specific activity values (obtained from the spectrophotometric assay) at each stage of purification of the enzyme from Lactobacillus casei and were found to give parallel results . The characteristics of the trichloracetic acid assay procedure, which exclusively detects covalent enzyme-ligand adducts, are compared to those for other ligand binding assays for thymidylate synthase.

Appl Environ Microbiol, 1990 May, 56(5), 1310 - 6
Lactobacillus succession in the piglet digestive tract demonstrated by plasmid profiling; Tannock GW et al.; Plasmid profiling was used to distinguish strains of lactobacilli inhabiting the digestive tract of piglets and the feces of sows . Fifteen plasmid profile types were detected among 328 isolates of lactobacilli . Plasmid profiling of lactobacilli permitted the following conclusions to be made: the maternal feces were a major source of lactobacilli colonizing the piglet digestive tract; the lactobacillus population of the gastric region of the piglet digestive tract was composed of lactobacillus strains different from those present in the rectal population; and a lactobacillus succession was observed in the digestive tract of piglets drawn from a single litter, and one plasmid profile type became dominant in the gastric region of these animals.

Minerva Stomatol, 1990 May, 39(5), 413 - 29
{The role of Streptococcus mutans in human caries}; Mosci F et al.; Definite proof has been found that S . mutans, and probably S . sobrinus and lactobacilli, are responsible for caries in man . The aciduria of S . mutans encourages the selection inside the plaque and is directly responsible for its cariogenicity . Other aciduric species, as S . sobrinus, cause caries on the smooth surface of the tooth, where the principal causes of the rampant caries reside . If during the eruption of the tooth the fissures become colonized in depth by S . mutans, the development of caries becomes a highly probable event . Instead, if the colonization of the tooth by S . mutans takes place after the fissure depth have been occupied by other microbic species not cariogenic, it is probable that the caries will not manifest or will appear in a less severe form . In conclusion, the knowledge already acquired on the ecology of S . mutans and the mechanism of cariogenesis clearly indicate that all factors that interfere with the colonization of the tooth by S . mutans can greatly reduce the incidence of caries in man.

J Dent Res, 1990 May, 69(5), 1205 - 10
Microbiology of root surface caries in humans; Bowden GH; Studies on the microbiology of root surface caries between 1970 and 1975 placed emphasis on Gram-positive pleomorphic filamentous rods, particularly Actinomyces viscosus and Actinomyces naeslundii . Both of these species had been shown to produce root surface caries in experimental animals . Since this time, studies have placed more emphasis on Streptococcus mutans, and S . mutans and Lactobacillus are significant in prediction of root surface caries risk in patients . Subsequent studies confirmed an association between S . mutans and 'soft' or 'initial' root lesions . Thus, it is important when determining the microflora of root surface lesions to make careful characterization of the state of the lesion . A second important aspect of the analysis of bacterial communities associated with root surface caries is better definition of the organisms . Most studies have concentrated on 'target organisms' S . mutans, S . sanguis, A . viscosus, A . naeslundii, Lactobacillus, and Veillonella . However, it has been known for 17 years that the Actinomyces associated with the lesions may be variants of A . viscosus and A . naeslundii . Such strains (intermediate strains) have been described in taxonomic studies of Actinomyces, yet little is known of the differences in physiology of these strains or their relationship to root surface caries . A similar situation exists with oral Streptococcus where new taxonomic divisions are being proposed . Recognition of the potential diversity within the 'target' genera of root surface caries could yield valuable data . Recent studies suggest that this is so, since samples from root surface lesions which contain S . mutans and Lactobacillus show a high isolation of S . mitis 1 and no isolations of A . naeslundii . Careful definition of the lesions of root surface caries and the flora will allow analysis to relate a specific bacterial community to the state fo the lesion and assist in monitoring the control of the lesion through fluoride and antibacterials.

J Environ Pathol Toxicol Oncol, 1990 May-Jun, 10(3), 149 - 53
Influence of aflatoxin B1 on gas production by lactic acid bacteria; Sutic M et al.; The main characteristic of homofermentative lactic acid bacteria is that they do not produce gas from glucose and other sugars . However, in these experiments Lactobacillus casei, Lb . plantarum and Streptococcus lactis in broth media with glucose, galactose, lactose and sucrose, and aflatoxin B1 produces acid and also a significant amount of gas . In the control media without aflatoxin, these bacteria did not produce gas . The data suggest that lactic acid bacteria, known until now as homofermentative, become heterofermentative because of the influence of aflatoxin B1 . The results of these investigations are of practical value because they may explain the defect of cheese "blowing," which can appear in Trapist cheese vacuum packed in foil . This type of unusual "blowing" occurs approximately one month after cheese manufacture . This defect can be characterized by very large holes and cracks inside the cheese . The flavor is similar to that of young cheese, which can be very undesirable for a ripened, Trapist, aged cheese.

Antibiot Khimioter, 1990 May, 35(5), 16 - 21
{Transfer of various markers in Lactobacilli during transformation of plasmid DNA and joint cultivation}; Tiurin MV et al.; A system providing a high frequency genetic transfer of various markers making the reference strain Lactobacillus buchneri 1837 resistant to Lm, Em and Fus, able to ferment some carbohydrates and antagonistic against Pseudomonas diminuta CCM 2657 was developed . The frequency of the marker transfer during the lactobacilli joint cultivation was 1.5 X 10(-5) = 5.5 X 10(-5) to 1.5 X 10(-4) = 5.5 X 10(-4) which was 3-4 orders of magnitude higher than the marker transfer frequency during transformation of L . buchneri NRRLB 1837 with plasmid DNA of different lactobacilli . The recombinants and transformants resulting from the joint cultivation of lactobacilli contained a plasmid about 60 kb in length which provided cells of L . buchneri NRRLB 1837 with resistance to fusidin, antagonistic activity against Pseudomonas diminuta and capacity for utilizing sucrose and sorbite . It was shown possible to integrate the plasmid DNA about 26.5 kb in length contained in the cells of L . casei MT 205 to the chromosomes of erythromycin resistant transformants . The results of the investigation of the biological properties of the recombinants and transformants and their plasmid profiles were confirmed with the Southern DNA-DNA hybridization.

J Dairy Res, 1990 May, 57(2), 255 - 64
Prevention of gastrointestinal infection using immunobiological methods with milk fermented with Lactobacillus casei and Lactobacillus acidophilus; Perdigon G et al.; The protective effect of feeding milk fermented with a mixture of Lactobacillus casei sp . and Lb . acidophilus sp . against Salmonella typhimurium infection in mice was compared with that obtained feeding milks fermented with these microorganisms individually . The survival rate obtained after oral infection with Sal . typhimurium was 100% in mice pretreated by feeding during 8 d with the mixture of Lb . casei and Lb . acidophilus fermented milks . Similar treatments with the individual milks were ineffective . Moreover, mice became more susceptible to infection with Sal . typhimurium after such treatment . The colonization of liver and spleen with the pathogen was markedly inhibited by the pretreatment with the mixture of fermented milk, while such inhibition was not observed using the Lb . casei and Lb . acidophilus milks . The highest levels of anti-salmonellae antibodies in serum and in intestinal fluid were found in the group of mice fed with the mixture and with Lb . casei fermented milk respectively . However, this latter milk was not effective in protecting against Sal . typhimurium . When the mice were first infected with Sal . typhimurium and then fed with the mixture of fermented milks, pathogen colonization was not prevented . The results suggest that the augmentation of resistance to salmonellae caused by the treatment with Lb . casei- + Lb . acidophilus-fermented milk was due to the anti-salmonellae protective immunity mainly mediated by the mucosal tissue . Milk fermented with this mixture could be used as an immunobiological method to prevent gastrointestinal infection.

J Nutr, 1990 May, 120(5), 476 - 84
Modulation of pteroylpolyglutamate concentration and length in response to altered folate nutrition in a comprehensive range of rat tissues; Ward GJ et al.; For a range of rat tissue extracts, the concentrations of total folates and of short-chain pteroylpolyglutamates were assayed by Lactobacillus casei with and without conjugase treatment, respectively, and the concentration and chain length of H4PteGlnn and 5,10-CH2-H4PteGlnn together were assayed after binding to thymidylate synthase and tritiated fluorodeoxyuridylate . For rats fed a nonpurified diet and consuming 26 micrograms of folic acid daily, the respective concentrations of these total folates, short-chain folates and thymidylate synthase bindable folates were, in nmol/g, 10.2, 2.5 and 3.5 in liver, 3.9, 1.8 and 2.0 in kidney, 4.2, 1.2 and 1.0 in bone marrow, 2.3, 0.6 and 0.2 in adrenal, 2.1, 0.3 and 0.5 in spleen, 2.1, 0.9 and 0.8 in jejunal smooth muscle, 1.2, 0.9 and 0.2 in jejunal mucosa, 1.0, 0.3 and 0.6 in testis, 0.7, 0.1 and 0.2 in heart, 0.3, 0.1 and 0.1 in skeletal muscle, 0.5, 0.1 and 0.3 in brain and 0.7, 0.002 and 0 in erythrocytes . The predominant pteroylpolyglutamate chain length was 6 residues in all tissues except kidney, jejunal mucosa, skeletal muscle and brain, in which the value was 5 residues . A folate-deficient diet (30 ng/d) fed for 3 wk resulted in a depression in the total folate concentration of all tissues (except brain); the depression was generally greater for short-chain than for long-chain folates and was accompanied by a lengthening of the pteroylpolyglutamate chain . Opposite results followed folate excess of 4 to 5.4 mg/d . The fractional change in the folate concentration of the individual tissues, following perturbation of dietary folate, did not vary greatly among tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Med Lab Sci, 1990 Apr, 47(2), 90 - 6
Cryo-preservation of Lactobacillus leichmannii for vitamin B12 microbiological assay; Kelleher BP et al.; An optimised method for preparing cryo-preserved cultures of Lactobacillus leichmannii for vitamin B12 microbiological assay is described . Cultures are mixed with an equal volume of 800 ml/l sterile glycerol before freezing . The percentage recovery of viable cells after thawing is highest when cultures are enclosed in polystyrene insulation and cooled to -70 degrees C . Cells cryo-preserved in the stationary phase of growth have a higher percentage recovery after thawing, but the same numbers of log phase cells give a larger growth response to cyanocobalamin under assay conditions . Cryo-preserved cultures are stable for many months, giving consistency of standard curve shape . Results obtained for control sera are also more consistent over time, with a range of CV values from 2.58% to 4.82%, as compared to a range of 4.63% to 6.11% for control sera in assays using conventionally prepared fresh cultures . The use of large inocula also allows for assay completion after overnight incubation.

Antimicrob Agents Chemother, 1990 Apr, 34(4), 632 - 6
Effect of ofloxacin combined with Lactobacillus casei against Mycobacterium fortuitum infection induced in mice; Tomioka H et al.; Multiple injections of ofloxacin (subcutaneous or oral) in combination with a Lactobacillus casei preparation, LC9018 (subcutaneous), in mice infected intravenously with Mycobacterium fortuitum led to a marked delay in the incidence of spinning disease, a lowered incidence of gross renal lesions, and an increase in the rate of elimination of organisms from the kidneys . This indicates synergism in the therapeutic efficacy of the two agents . When the antimicrobial ability of peritoneal macrophages (M phi s) against M . fortuitum was measured in medium with or without ofloxacin, growth of the organisms was more markedly inhibited by ofloxacin in LC9018-induced M phi s than in normal M phi s . Synergism in the therapeutic activity of oxfloxacin plus LC9018 is assumed to be mediated in part by host M phi s, that is, functional stimulation of host M phi s by LC9018 treatment results in the synergistic effects of the two agents.

Antimicrob Agents Chemother, 1990 Apr, 34(4), 543 - 9
Antimicrobial susceptibility of vancomycin-resistant Leuconostoc, Pediococcus, and Lactobacillus species; Swenson JM et al.; Eighty-five strains of vancomycin-resistant gram-positive bacteria from three genera, Leuconostoc, Pediococcus, and Lactobacillus, were tested to determine susceptibility to 24 antimicrobial agents by broth microdilution and to 10 agents by disk diffusion . The MICs of vancomycin and teicoplanin ranged from 64 to greater than 512 micrograms/ml; however, the MICs of daptomycin, a new lipopeptide, were all less than or equal to 0.25 micrograms/ml . None of the organisms were resistant to imipenem, minocycline, chloramphenicol, gentamicin, or daptomycin . The MICs of penicillin were in the moderately susceptible range for all but three strains . Susceptibility to the other agents varied by genus and, in some cases, by species . When disk diffusion results were compared with MICs for drugs recommended for streptococci by the National Committee for Clinical Laboratory Standards, Villanova, Pa., few very major or major errors were obtained, but the number of minor errors was 19.3% . Therefore, we recommended that MIC testing be used instead of disk diffusion testing for these organisms.

Rev Argent Microbiol, 1990 Apr-Jun, 22(2), 86 - 9
{Leuconostocs in raw milk: isolation and identification of species rapidly utilizing lactose}; Gonzalez FC et al.; Fast lactose fermenting Leuconostoc species and subspecies were isolated from raw milk . Samples were obtained from dairy farms of the surroundings of Buenos Aires city . A lactose, non selective, isolation medium was employed (YCL) . Differentiation of leuconostocs from Lactobacillus viridescens and L . confusus was avoided on account of the use of this medium . 801 typical colonies of lactic acid bacteria were selected from YCL agar; 710 of them were identified as lactic acid bacteria from which 114 strains belonged to the genus Leuconostoc . These last strains were then tested for species and subspecies differentiation by dextran production and sugar fermentation . Leuconostoc mesenteroides subsp . dextranicum and L . lactis were identified . Four strains identified as Leuconostoc spp do not belong to any known species.

Biochimie, 1990 Apr, 72(4), 265 - 9
Genetic transformation of Lactobacillus casei by electroporation; Natori Y et al.; Lactobacillus casei IAM1045 was transformed with a plasmid pAM beta 1-1, a tra deleted derivative of pAM beta 1, by electroporation . Effective transformation was achieved in electroporation buffers of a wide range of pH values, and in all phases of cell growth tested, with highest frequency in the early log phase . Polyethylene glycol increased the transformation frequency, whereas divalent cations such as Mg2+, Ca2+ and Mn2+ at 0.25 mM decreased the frequency by 2 to 3 orders . Highly efficient transformation of approximately 10(-4)/viable cell was achieved under optimal conditions . A plasmid harboring the trpD, C, F, B and A genes from L casei RNL7 was introduced by electroporation into tryptophan auxotrophic L casei JCM1053 . The resulting transformant was found to express the trp genes introduced.

J Dairy Sci, 1990 Apr, 73(4), 905 - 11
Factors to consider when selecting a culture of Lactobacillus acidophilus as a dietary adjunct to produce a hypocholesterolemic effect in humans; Gilliland SE et al.; Significant variations in bile tolerance and ability to assimilate cholesterol were observed among 12 cultures of Lactobacillus acidophilus of human origin . The degree of bile tolerance as measured by rapidity of growth in MRS broth supplemented with .3% oxgall could not be predicted by the rapidity of growth in the broth without oxgall . There was no apparent direct relationship between bile tolerance and cholesterol assimilation . However, among the cultures that most actively assimilated cholesterol, there were significant differences in bile tolerance . The most active cholesterol-assimilating cultures also varied in the ability to produce bacteriocins . A culture of L . acidophilus of human origin, which assimilates cholesterol, grows well in presence of bile, and produces bacteriocins can be selected for use as a dietary adjunct for humans . A culture of L . acidophilus possessing all these characteristics should have an advantage over one that does not in establishing and functioning in the intestinal tract to assimilate cholesterol.

Vaccine, 1990 Apr, 8(2), 150 - 2
Protective effect of heterologous gram-positive vaccine against lethal upper respiratory tract infection with type M50 group A streptococci in mice; Stjernquist-Desatnik A et al.; Type M50 group A streptococci are exceptional for their virulence in mice . However, intranasal (i.n.) vaccination with heat-killed group A streptococci, either of type M50 or M55, or an M12 strain deficient in M-protein, protected mice against i.n . challenge with M50 streptococci (82, 88 and 83% survival, respectively) . Significant resistance against M50 streptococci was also noted by i.n . application of heat-killed Lactobacillus fermenti (81% survival) as well as two strains of pneumococci (50 and 79% survival) . In contrast, no protective effect was obtained using heat-killed trypsin-treated M55 streptococci . Nor did vaccination with Escherichia coli and Pseudomonas aeruginosa induce protection against type M50 . Thus, M protein was not required for immunity against type M50 . The results call for a revision of the hitherto accepted view that M proteins are the only candidates for mucosal vaccines against group A streptococci.

DICP, 1990 Apr, 24(4), 382 - 4
A double-blind, placebo-controlled study of the efficacy of Lactinex in the prophylaxis of amoxicillin-induced diarrhea; Tankanow RM et al.; The disruption of the natural flora of the gastrointestinal tract (especially Lactobacillus acidophilus) may occur during antibiotic therapy . This may lead to diarrhea, dehydration, and electrolyte imbalances . It has been suggested that replacement of the lactobacilli with a commercially available product may prevent the diarrhea . The efficacy and safety of prophylactically administered Lactinex (culture of L . acidophilus and L . bulgaricus) was compared with placebo for the prevention of amoxicillin-induced diarrhea in pediatric patients . Lactinex or placebo was administered four times a day for ten days to coincide with the antibiotic therapy . The Lactobacillus preparation did not appear to consistently prevent diarrhea in this patient population . Patients' age, diet, and parental definition of diarrhea were factors that may have influenced the results.

Oral Microbiol Immunol, 1990 Apr, 5(2), 77 - 81
Salivary caries-related tests as predictors of future caries increment in teenagers . A three-year longitudinal study; Alaluusua S et al.; The aim of the study was to evaluate the capability of caries-related salivary tests and a test based on past caries experience (baseline DFS) to select persons at high risk for caries . The subjects (n = 122) were 12-17 years old at the beginning of the study . Caries was registered and salivary samples were taken annually during the 3-study period . The 3-year caries increment was positively correlated to the baseline DFS (r = 0.46, p less than 0.001), salivary level of mutans streptococci (r = 0.30, p less than 0.001) and lactobacilli (r = 0.30, p less than 0.001), and combined level of mutans streptococci and lactobacilli (r = 0.39, p less than 0.001) and negatively correlated to the buffering capacity of saliva (r = -0.22, p less than 0.05) . Tests based on either past caries experience or mutans streptococci or lactobacilli levels alone were not efficient in selecting persons at high risk for caries . Among the tests, DFS was the most sensitive and specific . A combination of either microbial test and DFS was more efficient to select persons at risk than various alternatives alone . The sensitivity was 84% and the specificity 62% for the combination of lactobacilli test and DFS and 71% and 79% respectively for the combination of mutans streptococci and DFS . In the former combination the positive prediction value was 43% and in the latter 56%.

Agric Biol Chem, 1990 Apr, 54(4), 937 - 41
Protoplast transfection of Lactobacillus casei by phage PL-1 DNA; Watanabe K et al.; Polyethylene glycol (PEG) mediated transfection of Lactobacillus casei ATCC 27092 protoplasts by phage PL-1 DNA was done . The protoplasts were obtained by treatment with purified PL-1 phage N-acetylmuramidase in the presence of citrate . Optimum conditions for transfection were 50% PEG 4,000, 15 micrograms protamine sulfate/ml, 0.15 M sucrose, and 10 mM MgSO4 in MR medium (pH 6.0) . The extent of transfection was proportional to the amounts of DNA added, and the greatest efficiency of transfection after a 10-min incubation was about 3.3 x 10(5) PFU/micrograms DNA . The eclipse period of growth of progeny phages in the transfectants was 3 hr and the average burst size was 200.

Mol Gen Mikrobiol Virusol, 1990 Mar, (3), 29 - 31
{Optimization of the method of isolation of microamounts of plasmid DNA from lactobacilli}; Tiurin MV; Modification of the alkaline lysis at elevated temperature technique is proposed isolation of plasmid DNA from lactobacilli . Modification consists of colorimetric control of culture phase during the biomass growth, pH control at the probes treatment with lysozyme and alkaline solution of natrium dodecylsulfate by adding the indicator bromcrezolpurple into the medium for biomass growth . The high concentration of lysozyme is used (10 mkg.ml-1) . Lactobacilli are lysed at 2 min incubations of the probes with the lytic solution in the boiling water bath . The treatment of the probes by proteinase K, by the mixture of chloroform:phenol:isoamyl spirit (25:24:1 vol/vol/vol) and by diethylpirocarbonate increased considerably the quality of the obtained DNA preparations . The modified technique is suitable for isolation of the plasmid DNA from lactobacilli of different species, enterococci, streptococci and other lactic bacteria . The connection of antibiotic resistance marker and the plasmid profile of lactobacilli under different conditions with the presence of the plasmid DNA- protein complex is discussed.

Appl Environ Microbiol, 1990 Mar, 56(3), 724 - 9
Assay for the enzymatic conversion of indoleacetic acid to 3-methylindole in a ruminal Lactobacillus species; Honeyfield DC et al.; An assay to measure the rate of enzymatic formation of 3-methylindole (3MI) from indoleacetic acid (IAA) in Lactobacillus sp . strain 11201 was developed . The reaction mixture contained 50 micrograms of microbial protein per ml (range, 25 to 100 mg/ml), essential low-molecular-weight reaction ingredients, and radiolabeled IAA as substrate (range, 0 to 2 mM IAA) . The reaction was anaerobic for 25 min at 39 degrees C . The apparent Michaelis-Menten constants were: Km, 0.14 mM IAA; and Vmax, 64 nmol 3MI.mg-1.min-1 . The inhibitors avidin, aminopterin, and EDTA had no effect on the 3MI-forming enzyme . Dithionite stimulated the 3MI-forming enzyme . The product of the reaction, 3MI, acted as a noncompetitive inhibitor of the enzyme . Enzyme activity was associated with the cell wall fraction after sonication; treatment with the French press; or treatment with detergents, proteolytic enzymes, and EDTA.

ZWR, 1990 Mar, 99(3), 167 - 73
{Possibilities of assessing the individual caries risk using microbiological parameters}; Einwag J et al.; The most commonly used microbiological tests for identifying patients with high caries activity are based on quantitative or semi-quantitative counts of Streptococcus mutans and Lactobacilli . In a review the prognostic value of such tests is discussed and shown, that in spite of partially high prediction rates, the prognostic value of either S . mutans or Lactobacillus tests can be confirmed only in combination with additional relevant clinical parameters (e.g . anamnesis, DMF-increment, secretation rate and bufferin capacity of saliva...).

Infection, 1990 Mar-Apr, 18(2), 65 - 9
Single dose and conventional treatment for acute bacterial and non-bacterial dysuria and frequency in general practice; Cooper J et al.; A five day course of clavulanate-potentiated amoxicillin (Augmentin) has been compared with a single oral dose of fosfomycin trometamol in the treatment of patients complaining of symptoms suggesting urinary tract infection . The study took place in a single urban general practice of 15,000 patients in Cheshire . The microbiology was performed at a London Teaching Hospital . 141 patients entered the trial . 65 had a significant bacteriuria, 62 of which were assessable for the ability of the trial drugs to eradicate bacteriuria: 29 patients received clavulanate-potentiated amoxicillin and 33 fosfomycin trometamol . The cure rates, assessed at five to ten days and at four to six weeks post treatment, were 72% and 65%, respectively for clavulanate-potentiated amoxicillin and 85% and 81%, respectively for fosfomycin trometamol . Side effects, assessed in all 141 patients, occurred in 11.6% receiving clavulanate-potentiated amoxicillin and in 8.3% receiving fosfomycin . Statistically there is no difference between any of these findings and the effect of sample size is discussed . 69 patients were symptomatic but did not have a significant bacteriuria ("urethral syndrome") . These patients were assessed for the effect of treatment in relieving symptoms: 33 received fosfomycin trometamol and 36 clavulanate-potentiated amoxicillin . The success and speed of relieving the symptoms were very similar in the two groups . The finding that both groups responded equally well appears to refute an aetiological role for lactobacilli and diphtheroids in the "urethral syndrome", since these organisms are resistant to fosfomycin but sensitive to clavulanate-potentiated amoxicillin.

J Anim Sci, 1990 Mar, 68(3), 758 - 66
Inhibition of proteolysis at harvest using heat in alfalfa silages: effects on silage composition and digestion by sheep; Charmley E et al.; Heat treatment at harvest was used to investigate the effects of proteolysis on silage composition and digestion by sheep . Four alfalfa (Medicago sativa) silages were prepared, two from mid-bloom and two from pre-bloom crops from the same field . Mid-bloom alfalfa was conserved with formic acid as two unwilted silages, either without (unwilted control; UWC) or after heat treatment (unwilted heated; UWH) applied as steam for 1 min . Pre-bloom alfalfa was ensiled either after 24 h wilting (wilted control; WC) or after heating in a crop dehydrator for 2 min (wilted control; WH) . Heated treatments were inoculated with Lactobacillus plantarum . Eight wethers, cannulated in the rumen and duodenum, were given the silages to determine the effects of heat treatment on digestion . Heat treatment inhibited protease activity and reduced protein catabolism in the silo . In unwilted silages, heat treatment had no effects (P greater than .05) on OM or N digestion, but it reduced (P less than .05) CP degradability in the rumen . In wilted silages, heat treatment reduced (P less than .05) apparent OM digestion in the rumen and increased (P less than .05) the proportion of N intake flowing to the intestines as non-ammonia N (NAN) . Efficiency of microbial protein synthesis also was increased (P less than .01) . Absorption of N posterior to the duodenum was increased (P less than .05) in WH compared to WC, but there was no effect (P greater than .05) of heat treatment on apparent total tract N digestibility.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasmid, 1990 Mar, 23(2), 119 - 25
Characterization of plasmids and plasmid-borne macrolide resistance from Lactobacillus sp . strain 100-33; Rinckel LA et al.; Lactobacillus sp . strain 100-33 is resistant to macrolides, lincosamides, and streptogramin B-type antibiotics (MLSR) and appears to contain several major and minor plasmids . One of these plasmids, pLAR33, is approximately 18 kbp in size . When cells of strain 100-33 were protoplasted and regenerated, an MLSS isolate was derived . The derivative, designated strain ES1, contained a unique plasmid complement in which it had apparently lost the major plasmids of the parental strain, including pLAR33, and retained only a minor plasmid seen in low concentrations in strain 100-33 . The MLSR determinant was cloned from plasmid DNA of strain 100-33 on a 3-kbp EcoRV fragment into pBR322 and localized to pLAR33 . The determinant expressed macrolide and lincosamide resistance in Escherichia coli HB101, was localized to approximately 1 kbp on the cloned sequence, and is apparently under the control of its own promoter . MLSR electroporants were derived from strain ES1 electroporated with plasmid DNA from strain 100-33; these MLSR isolates had acquired a plasmid complement similar to that of strain 100-33, including pLAR33 . Endonuclease digestion and Southern analysis of plasmid DNA from both strains indicated that the major plasmids are multimeric and deleted forms of one archetypal extrachromosomal element.

J Clin Microbiol, 1990 Mar, 28(3), 484 - 8
Recovery of vancomycin-resistant gram-positive cocci from children; Green M et al.; A cross-sectional survey of vancomycin-resistant gram-positive cocci (VRGPC) in the feces of children was initiated after several bacteremic infections with these organisms occurred at our hospital . A selective medium consisting of colistin-nalidixic acid agar, 5% sheep blood, vancomycin (5 mg/liter), and amphotericin B (8 mg/liter) was developed to isolate VRGPC . A single stool specimen submitted to the clinical microbiology laboratory from each of 48 patients was inoculated onto the medium . Plates were incubated at 35 degrees C with 5% carbon dioxide and examined at 24, 48, and 72 h . Susceptibilities were determined by broth microdilution . A total of 14 isolates from 11 of 48 (22%) children were recovered . The density of growth ranged from a single colony to 2+ . The VRGPC were identified as Leuconostoc lactis (n = 2), Lactobacillus confusus (n = 4), Enterococcus species (n = 5), and Lactococcus lactis (n = 3) . One strain of Lactobacillus confusus was recovered from both the stool and the blood of one of these patients . The MICs of vancomycin were 4 micrograms/ml for one of the isolates, 8 micrograms/ml for four of the isolates, and more than 16 micrograms/ml for the remaining eight isolates . All isolates were susceptible to both penicillin and ampicillin . Only 1 of the 11 children had received prior treatment with vancomycin . We conclude that low concentrations of VRGPC may be common in the gastrointestinal tracts of children.

Arch Biochem Biophys, 1990 Mar, 277(2), 334 - 41
Tetrahydrohomofolate polyglutamates as inhibitors of thymidylate synthase and glycinamide ribonucleotide formyltransferase in Lactobacillus casei; Thorndike J et al.; In order to determine the mechanism for the effects of homofolates on growth of Lactobacillus casei, polyglutamated derivatives of homofolate (HPteGlu), dihydrohomofolate and tetrahydrohomofolate (H4HPteGlu) were synthesized and tested as inhibitors of folate-requiring enzymes . The following L . casei enzymes were examined: thymidylate synthase (TS), glycinamide ribonucleotide formyltransferase (GARFT), aminoimidazolecarboxamide ribonucleotide formyltransferase, serine hydroxymethyltransferase and dihydrofolate reductase . Polyglutamates of (6R,S)-H4HPteGlu are potent inhibitors of TS and GARFT . For example, the IC50 values of (6R,S)-H4HPteGlu6 are 0.7 microM for TS and 0.3 microM for GARFT . By contrast, the value for HPteGlu6 is greater than 10 microM for both TS and GARFT . Inhibition of TS and GARFT by (6R,S)-H4HPteGlu derivatives increases with polyglutamate chain length . For TS, the Glu5 and Glu6 derivatives of (6R,S)-H4HPteGlu are 20 and 30 times more potent than the monoglutamate, respectively . For GARFT, the Glu2-6 derivatives are 2-3 times more potent than Glu1 . Inhibition of TS and GARFT by (6R,S)-H4HPteGlu polyglutamates is almost entirely due to the unnatural (6R) diastereomer at C-6 . Homofolate derivatives are only weak inhibitors of aminoimidazolecarboxamide ribonucleotide formyltransferase, serine hydroxymethyltransferase, and dihydrofolate reductase . We conclude that both TS and GARFT are potential targets of (6R)-H4HPteGlu polyglutamates.

J Biol Chem, 1990 Feb 15, 265(5), 2682 - 3
Crystallization and preliminary X-ray investigation of recombinant Lactobacillus leichmannii nucleoside deoxyribosyltransferase; Cook WJ et al.; Crystals of recombinant bacterial nucleoside deoxyribosyltransferase have been grown from solutions of ammonium sulfate . The crystals are cubic, space group I23 or I2(1)3; the axial length is 151.1(2) A . The crystals are stable to x-rays for at least 5 days and diffract beyond 2.8-A resolution . It appears that the molecule, which is a hexamer, utilizes the symmetry of the space group, resulting in two or three subunits per asymmetric unit.

J Biol Chem, 1990 Feb 15, 265(5), 2492 - 9
Cloning and expression of the gene encoding Lactobacillus casei folylpoly-gamma-glutamate synthetase in Escherichia coli and determination of its primary structure; Toy J et al.; A genomic library of Lactobacillus casei DNA containing 10,000 individual clones was constructed in the plasmid pUC13 . The gene encoding the L . casei folylpolyglutamate synthetase was isolated from the library by complementation of a folC mutant of Escherichia coli . The gene was expressed in E . coli from its own promoter and produced amplified folylpolyglutamate synthetase activity with properties identical with those of the purified L . casei enzyme . The absence of dihydrofolate synthetase activity and the preferential utilization of 5,10-methylenetetrahydrofolate, rather than 10-formyltetrahydrofolate as folate substrate, distinguishes this activity from the E . coli folylpolyglutamate synthetase-dihydrofolate synthetase . A protein of Mr = 43,000, identical with that of purified L . casei folylpolyglutamate synthetase, was expressed in maxicells containing the complementing plasmid . The nucleotide sequence of the folylpolyglutamate synthetase gene was determined . An open reading frame of 1,284 bases was found predicting a protein product of 428 amino acids with Mr = 44,169 . The predicted amino acid sequence of the gene is 33% homologous to that of the E . coli folylpolyglutamate synthetase . Primer extension studies indicate that the transcription initiation site is at -59 base pairs, relative to the initiation ATG codon of the folylpolyglutamate synthetase gene, suggesting that the gene is transcribed independently of upstream genes . A second open reading frame was found downstream of the folylpolyglutamate synthetase open reading frame, overlapping the final codon by 1 base pair . This downstream gene may be co-transcribed with the folylpolyglutamate synthetase gene.

Ann Surg, 1990 Feb, 211(2), 165 - 71
The bacteriology of gangrenous and perforated appendicitis--revisited; Bennion RS et al.; By using optimum sampling, transport, and culture techniques in patients with gangrenous or perforated appendicitis, we recovered than has previously been reported . Thirty patients older than 12 years with histologically documented gangrenous or perforated appendicitis had peritoneal fluid, appendiceal tissue, and abscess contents (if present) cultured . Appendiceal tissue was obtained so as to exclude the lumen . A total of 223 anaerobes and 82 aerobic or faculatative bacteria were recovered, an average of 10.2 different organisms per specimen . Twenty-one different genera and more than 40 species were encountered . Bacteroides fragilis group and Escherichia coli were isolated from almost all specimens . Within the B . fragilis group, eight species were represented . Other frequent isolates included Peptostreptococcus (80%), Pseudomonas (40% {P . aeruginosa, 23.3%, other Pseudomonas spp., 16.7%}), B . splanchnicus (40%), B . intermedius (36.7%), and Lactobacillus (36.7%) . Interestingly a previously undescribed fastidious gram-negative anaerobic bacillus was isolated from nearly one half of all patients . This organism was found to have low DNA homology (by dot blot) with the known organisms most closely resembling it.

Jpn J Antibiot, 1990 Feb, 43(2), 321 - 5
{Comparative study of the bacterial flora in both uterocervical and uterine regions}; Chimura T et al.; The relationship between indigenous bacterial floras in the lower genitals and the uterocervical region is of importance due to a barrier-like role against ascending infections through the mechanism of the localized protection at a boundary of the uterocervical region . Therefore, bacterial flora in the uterocervical and uterine regions was studied in cases for which gynecological operations were performed (n = 77) . 1 . Ratios of incidences of the detection of bacteria on the uterocervical and in the uterine regions were 50/77 (64.9%) and 6/77 (7.8%), respectively . When different age groups are compared, the detection ratio from the uterocervical region was high among patients in the 40 s, and all the cases in which bacteria were detected from the uterine region were in the 40 s . 2 . Gram-positive bacteria were detected at a high ratio, and anaerobic bacteria were noted in the uterocervical region, and ratios of detection of Staphylococcus epidermidis, Lactobacillus sp . and Propionibacterium acnes were high . Six strains of Gram-positive bacteria and 1 strain of Candida sp . were noted in the uterine region . 3 . When cefmetazole (CMZ) was administered for the prevention of the infections after these panhysterectomy cases examined here, no postoperative infectious diseases nor adverse reactions were noted.

Scand J Dent Res, 1990 Feb, 98(1), 1 - 7
Antibacterial activity of dental gels containing combinations of amine fluoride, stannous fluoride, and chlorhexidine against cariogenic bacteria; Ostela I et al.; The in vitro susceptibility of Streptococcus mutans, S . sobrinus and Lactobacillus casei to dental gels containing various combinations of amine fluoride (AmF 297), stannous fluoride (SnF2), and chlorhexidine (CHX) was studied . The combination of AmF-SnF2 with a total fluoride content of 1.2% was the most effective against mutans streptococci but not against L . casei . At notably lower total fluoride concentration (0.4%), AmF as such or combined with SnF2, was significantly less effective against mutans streptococci than CHX or CHX-AmF-SnF2 combinations . CHX-AmF combination was a slightly more potent inhibitor of streptococcal growth than CHX-NaF . With L . casei the differences between various gels were small but CHX alone seemed to be the most effective . Of the studied agents, CHX seemed to be the most potent individual chemotherapeutic compound whose activity against S . mutans could be enhanced by combining it with AmF . However, clinical experiments are required to test the in vivo antibacterial efficacy of CHX-AmF and AmF-SnF2 combinations which were most effective in our in vitro experiments.

Am J Vet Res, 1990 Feb, 51(2), 203 - 6
Effects of exocrine pancreatic insufficiency and replacement therapy on the bacterial flora of the duodenum in dogs; Simpson KW et al.; The influence of pancreatic secretions on the bacterial flora of the small intestine in 6 dogs was investigated by determining effects of exocrine pancreatic insufficiency on numbers and types of bacteria in duodenal juice, and by examining the subsequent response to dietary supplementation with bovine pancreatic extract . Exocrine pancreatic insufficiency was induced by ligation of pancreatic ducts and was confirmed by indirect assessment of exocrine pancreatic function . Duct ligation was followed by large increases (P less than 0.01) in total numbers of bacteria, reflecting increased numbers particularly of Lactobacillus spp and Streptococcus spp, in 3 dogs accompanied by obligate anaerobes . Total numbers of aerobes and anaerobes decreased markedly (P less than 0.05) after supplementation with bovine pancreatic extract to values that were not significantly different from those determined before duct ligation . Exocrine pancreatic insufficiency therefore resulted in small intestinal bacterial overgrowth that was reversed by pancreatic replacement therapy, indicating that pancreatic secretions can have an important influence on the small intestinal bacterial flora of dogs.

Community Dent Oral Epidemiol, 1990 Feb, 18(1), 17 - 21
Salivary levels of mutans streptococci, Lactobacillus, Candida, and Veillonella species in a group of Scottish adolescents; Russell JI et al.; Salivary levels of mutans streptococci, Lactobacillus, Candida, and Veillonella species were investigated on three occasions at annual intervals in a group of 372 Scottish adolescents . Counts of the micro-organisms studied were logarithmically distributed, with Candida spp . being isolated from approximately half the subjects . Counts of lactobacilli, mutans streptococci, and candida were significantly intercorrelated, while veillonella were associated consistently with mutans streptococci alone . Levels of each of the four micro-organisms were significantly correlated over the three examinations, with levels of the Candida spp . being the most stable over the period studied.

Ann Med, 1990 Feb, 22(1), 53 - 6
Prevention of travellers' diarrhoea by Lactobacillus GG; Oksanen PJ et al.; A placebo-controlled double-blind study was conducted on the efficacy of Lactobacillus GG in preventing travellers' diarrhoea . Altogether 820 persons travelling on holiday to southern Turkey to two destinations were randomized into two groups receiving either Lactobacillus GG or placebo in identical sachets . On the return flight each participant completed a questionnaire indicating the incidence of diarrhoea and related symptoms during the trip . Of the original group 756 (92%) subjects completed the study acceptably . The overall incidence of diarrhoea was 43.8% (331 cases) . The total incidence of diarrhoea in the placebo group was 46.5% and in the Lactobacillus GG 41.0% indicating an overall protection of 11.8% . Protection rates varied between two different destinations with the maximum protection rate reported as 39.5% . Among older age groups there was significantly less diarrhoea when compared to younger travellers . Lactobacillus GG appeared to be effective in reducing the occurrence of travellers' diarrhoea in one of the two destinations with no side effects.

Nippon Hotetsu Shika Gakkai Zasshi, 1990 Feb, 34(1), 167 - 74
{Bacterial penetration of bovine dentinal tubules . 1}; Mukai N et al.; The penetration by bacteria through dentinal tubules was studied using a device that included portion of bovine anterior teeth . Strains of 4 genera, Streptococcus mutans, Lactobacillus casei, Staphylococcus aureus and Escherichia coli, were used for the experiment, and the effects of acid etching of dentin on the penetration of bacteria through the dentin was examined . The time required for penetration through dentinal tubules of acid-etched samples was shorter than that of unetched samples . The minimum time required for half the samples to become positive for bacterial penetration through dentin MPT50 was 4 hours for all strains chosen when the acid-etched dentin was the target . In non-acid etched samples, the MPT50 varied among the genera and ranged from 20 hours to 48 hours; the speed of penetration was Sta . aureus = L . casei greater than Str . mutans greater than E . coli . Observation under the scanning electron microscope indicated that the smeared layer was completely coated on the surface of the prepared cavity, and when bacterial penetration occurred, a portion of the smear layer on the dentin disappeared . In longitudinal sections, the penetration by the bacteria into the tubules was visible . From these results, it is suggested that the smeared layer have an important effects on bacterial penetration through these tubules.

J Biochem (Tokyo), 1990 Feb, 107(2), 248 - 55
Nucleotide sequences and genomic constitution of five tryptophan genes of Lactobacillus casei; Natori Y et al.; Five trp genes, trpD, trpC, trpF, trpB, and trpA, of Lactobacillus casei were cloned by transformation of tryptophan auxotrophic mutants of the respective trp genes in Escherichia coli . These trp genes appear to constitute an operon and are located in the above order in a segment of DNA of 6,468 base pairs . The entire nucleotide sequence of this DNA segment was determined . Five contiguous open reading frames in this segment can encode proteins consisting of 341, 260, 199, 406, and 266 amino acids, respectively, in the same direction . The amino acid sequences of these proteins exhibit 25.5-50.2% homology with the amino acid sequences of the corresponding trp enzymes of E . coli . Two trp genes, trpC and trpF, from L . casei can complement mutant alleles of the corresponding genes of E . coli . However, neither the trpA gene nor the trpB gene of L . casei can complement mutations in the E . coli trpA gene and the trpB gene, respectively, suggesting that the protein products of the L . casei and E . coli trpA and trpB genes, respectively, cannot form heterodimers of tryptophan synthetase with activity . Other features of the coding and flanking regions of the trp genes are also described.

Indian J Biochem Biophys, 1990 Feb, 27(1), 18 - 22
Pentose synthesis in glucose-grown cells of Lactobacillus casei; Menezes L et al.; The pathway of pentose synthesis in glucose-grown cells of Lactobacillus casei was ascertained . Glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were present in glucose-grown cells, while transaldolase and transketolase were present only in traces . This suggested that only the oxidative arm of this pathway was operative in glucose-grown cells . On the other hand, in ribose-grown cells, transaldolase was induced with a concomitant suppression of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase . These results were confirmed by the detection of labelled CO2 produced by L . casei grown on {1-14C}glucose . The activities of the enzymes of the oxidative pentose phosphate pathway as also the rate of CO2 formation were higher in the exponential phase of growth as compared to the stationary phase, when the requirement of the cells for pentoses for the formation of DNA and RNA was higher.

Antibiot Khimioter, 1990 Feb, 35(2), 15 - 9
{Penicillin-binding proteins of various strains of Lactobacillus}; Griaznova NS et al.; Sensitivity of different species of Lactobacillus i.e . L . casei, L . plantarum, L . acidophillus, L . buchneri, L . jugurti and others to penicillins and cephalosporins of various generations was studied . Penicillin binding proteins (PBPs) of the Lactobacillus species were specified . It was shown that the number of PBPs depended on the Lactobacillus species . L . casei had the least number of PBPs (4) and L . brevis had the highest number of PBPs (11) . Competition of 14C-benzylpenicillin with ampicillin, cefotaxime, ceftizoxime and cefoperazone for binding to separate PBPs in three strains of different Lactobacillus species was investigated.

Oral Microbiol Immunol, 1990 Feb, 5(1), 33 - 8
Sorbitol-fermenting predominant cultivable flora of human dental plaque in relation to sorbitol adaptation and salivary secretion rate; Kalfas S et al.; The sorbitol-fermenting predominant flora of human dental plaque was studied in 12 people with low and 11 with normal salivary secretion rates before and after a period of frequent mouth rinses with sorbitol solution . A total of 277 sorbitol-fermenting isolates are described by their morphological and physiological characteristics . The flora was almost exclusively composed of gram-positive bacteria belonging to the genera Streptococcus, Lactobacillus and Actinomyces in people with low secretion rates and Streptococcus and Actinomyces in those with normal salivation . At the species level, Streptococcus mutans predominated in all . The frequent use of sorbitol resulted in an increase of the streptococcal species mainly and particularly of Streptococcus sanguis I in people with normal salivation . The counts of lactobacilli and Actinomyces remained unaffected . Almost all isolates appeared to belong to the resident plaque flora . Succession of new sorbitol-fermenting genera to the plaque community could not be observed as a result of the frequent exposure of the mouth to sorbitol.

Oral Microbiol Immunol, 1990 Feb, 5(1), 12 - 8
Maternal caries incidence and salivary close-contacts with children affect antibody levels to Streptococcus mutans in children; Aaltonen AS et al.; Serum and salivary immunoglobulins and antibodies reactive with Streptococcus mutans were determined in 67 5-8-year-old children . The children of mothers whose caries incidence rates exceeded the median value had significantly more serum IgG antibodies to S . mutans than those with a lower maternal caries activity (p less than 0.05) . The children (n = 14) who had been exposed to frequent maternal salivary close-contacts in their first year had significantly higher (p less than 0.05) serum total specific IgG antibodies but significantly lower (p less than 0.01) high-avidity IgG antibodies to S . mutans than the other children (n = 53) with less frequent close-contacts . The maternal caries incidence rates were significantly positively associated with children's dfs/DFS-indices (r = 0.41; p less than 0.001) . However, the high maternal caries incidence did not increase the risk of caries in those children whose mothers' saliva contained high amounts of lactobacilli during the first nursing year, when compared with matched children with a low maternal level of lactobacilli . This was possibly due to the fact that the former children had significantly (p less than 0.05) more anti-S . mutans IgG antibodies in their sera than the latter.

Appl Microbiol Biotechnol, 1990 Feb, 32(5), 538 - 43
Purification and characterization of acid urease from Lactobacillus fermentum; Kakimoto S et al.; Acid urease was purified to an electrophoretically homogeneous state, and the molecular weight was estimated to be 220,000 . The enzyme consisted of three kinds of subunits, designated alpha, beta and gamma, with molecular weights of 67,000, 16,800 and 8600, respectively, in a (alpha 1 beta 2 gamma 1)2 structure . The isoelectric point of the enzyme was 4.8 . The nickel content was found to be 1.9 atoms of nickel per alpha 1 beta 2 gamma 1 unit . The amino acid profile was different from those of known bacterial neutral ureases . The enzyme was most active at pH 2 and around 65 degrees C . It was stable between pH 3 and 9, and below 50 degrees C . The Km for urea was 2.7 mM at pH 2 . The enzyme activity was inhibited by Ag+, Hg2+, Cu2+, p-chloromercuribenzoate and acetohydroxamate . The enzyme was separated into three subunits by reverse phase HPLC . The amino terminal amino acid sequences of the subunits alpha, beta and gamma were Ser-Phe-Asp-Met-, Met-Val-Pro-Gly- and Met-Arg-Leu-Thr-, respectively.

Int Endod J, 1990 Jan, 23(1), 20 - 7
Predominant obligate anaerobes invading the deep layers of root canal dentin; Ando N et al.; This study was carried out to investigate the presence and types of bacteria invading the deep layers (0.5-2.0 mm from the surface of the root canal wall) of infected dentine of human root canals by sampling with an anaerobic glove box system the split surfaces of eight freshly extracted teeth . More bacteria were recovered after incubation in an anaerobic glove box than after aerobic incubation in air with 30 per cent CO2 . Out of 256 predominant bacterial isolated, 205 isolates (80 per cent) were obligate anaerobes . These findings suggest that the environment of deep layers of endodontic dentinal lesions is anaerobic and favours the growth of anaerobes . Among the obligate anaerobic isolates, strains belonging to Lactobacillus (30 per cent) and Streptococcus (13 per cent) were predominant, followed by Propionibacterium (9 per cent) . No strains of obligate anaerobic Gram-negative rods were isolated . The microflora of deep layers of infected root dentine is somewhat similar to that of the deep layers of carious lesions in coronal dentine.

Proc Finn Dent Soc, 1990, 86(1), 9 - 14
Effect of chlorhexidine-sodium fluoride gel applied by tray or by toothbrush on salivary mutans streptococci; Ostela I et al.; A chlorhexidine (1%)-sodium fluoride (0.2%) gel applied using a dental tray six times during two consecutive days significantly decreased salivary levels of mutans streptococci but had only a slight effect on salivary levels of lactobacilli . The same gel used as a dentifrice for one week (twice a day) also significantly reduced salivary levels of mutans streptococci . However, this treatment was somewhat less effective than that using trays, on the basis of the ratio of mutans streptococci to total aerobes . With both treatments baseline salivary levels of mutans streptococci were re-attained after 70 days . One day after the gel treatment, mutans streptococci were unable to adhere to plastic strips (Dentocult SM Strip mutans) but detectable growth was found on mitis-salivarius-bacitracin agar . This suggests that not only are numbers of mutans streptococci reduced after chlorhexidine-sodium fluoride gel treatment but also mutans streptococci adherence.

Biochem Cell Biol, 1990 Jan, 68(1), 33 - 43
On the basic structure of poly(glycerophosphate) lipoteichoic acids; Fischer W et al.; Poly(glycerophosphate) lipoteichoic acids from 24 Gram-positive bacteria of the genera Bacillus, Enterococcus, Lactobacillus, Lactococcus, Listeria, Staphylococcus, and the streptococcal pyogenic and oral group were analyzed . The 1,3-linked poly(glycerophosphate) structure was proved by analysis of glycerol and glycerophosphates after acid and alkaline hydrolysis . Using the molar ratios of glycolipid to phosphorus (A) and phosphomonoester to phosphorus after periodate oxidation followed by hydrazinolysis (B) or beta-elimination (C), we show that all lipoteichoic acids contain a single unbranched poly(glycerophosphate) chain and that the chain is uniformly phosphodiester-linked to C-6 of the nonreducing hexopyranosyl residue of the glycolipid moiety . On some chains minor phosphate-containing substituents were detected whose structure remains to be clarified . The lipoteichoic acids of enterococci and listeria strains were separated by hydrophobic interaction chromatography into glycolipid- and phosphatidylglycolipid-containing molecular species . The phosphatidylglycolipid moieties were structurally characterized after liberation from lipoteichoic acids with moist acetic acid . After periodate oxidation of lipoteichoic acids beta-elimination released both phosphatidic acid and the poly(glycerophosphate) chain . This indicates together with the sequence analysis of the released phosphatidylglycolipid that the phosphatidyl residue is located at C-6 of the reducing hexosyl residue of the glycolipid moiety and the poly(glycerophosphate) chain at C-6 of the nonreducing one . Together with earlier observations these results complete the evidence for the structural and possibly biosynthetic relationship between lipoteichoic acids and glycerophosphoglycolipids.

Clin Lab Haematol, 1990, 12(1), 87 - 95
Use of beta-lactamase to hydrolyse interfering antibiotics in vitamin B12 microbiological assay using Lactobacillus leichmannii; Kelleher BP et al.; The presence of certain antibiotics in patients' sera can invalidate microbiological assays for vitamin B12 using Lactobacillus leichmannii by inhibiting organism growth . Analysis of 3291 consecutive serum vitamin B12 assays in a large general hospital service showed inhibition of growth in 303 samples (9.2%) . In nearly all cases the interfering substance was a beta-lactam antibiotic . The value of using a beta-lactamase preparation to eliminate antibiotic effects was studied using antibiotic-containing patient sera and also normal serum to which antibiotics were added . In-vitro additions of penicillins, cephalosporins, and other antibiotics to normal serum resulted in varying levels of organism inhibition, but excellent recovery of a control value after treatment with beta-lactamase (greater than 98%) . Patient sera showing inhibition were reassayed in duplicate following treatment with beta-lactamase (n = 200), the overall effectiveness of the treatment being verified by the excellent recovery (greater than 98%) of a cyanocobalamin 'spike' added to a control . In only 0.2% of cases (6 of 3291 samples) was this treatment ineffective and it has thus proved an efficient method of eliminating the problem of antibiotic interference in the vitamin B12 microbiological assay.

Caries Res, 1990, 24(1), 52 - 8
Effect of dental plaque age and bacterial composition on the pH of artificial fissures in human volunteers; Igarashi K et al.; Changes in sucrose-induced plaque pH profiles and the microbial composition of occlusal tooth surface fissures were analyzed using wire telemetry and bacterial culturing techniques . Four human volunteers wore appliances containing artificial fissures constructed with ion-sensitive field-effect transistor (ISFET) electrodes for 1, 2 and 4 days; 1 subject kept the electrode for 3 weeks . After monitoring the plaque pH response at the base of the fissure to a 10% (w/v) sucrose rinse the plaque was removed and analyzed for total viable bacteria, total and specific streptococci, lactobacilli and Actinomyces spp . One-day-old plaque showed a rapid drop in plaque pH to a minimum of 4.8 +/- 0.2, with 2-day-old plaque showing the most acidogenic pH profile (minimum pH 4.6 +/- 0.2) . The 4-day-old plaque response was less acidogenic (minimum pH 5.0 +/- 0.3) than the results from days 1 and 2 . Responses from 13- and 21-day-old fissure plaques showed greatly decreased acidogenic responses (day 21 minimum pH 5.7) . Viable bacteria recovered from the fissure increased from approximately 4 x 10(6) colony-forming units on day 1 to 1.2 x 10(7) on days 2 and 4 and 1.7 x 10(7) on day 21 . Streptococci (greater than 50%) and Actinomyces (greater than 10%) dominated in the fissure plaques and their levels were related to minimum pH . Since fissure plaque of all ages tested contained high concentrations of acidogenic bacteria, the decreased acidogenic response at the base of fissures with increasing plaque age suggests that maturing fissure plaques provide an increasingly greater diffusion barrier to fermentable carbohydrates.

Caries Res, 1990, 24(4), 273 - 8
Effect of extraction of partly erupted third molars on salivary microbial counts in conscripts; Rajasuo A et al.; Viable counts of mutans streptococci, lactobacilli and yeasts in saliva were followed for 5 months after extraction of partly erupted third molars in 49 conscripts aged 19.9 +/- 0.8 years . For controls, 27 conscripts aged 19.7 +/- 1.2 years were studied who did not have indications for third molar extractions . The microbiological analyses were made from paraffin-wax-stimulated saliva using dip-slide techniques . The results showed a statistically significant reduction of the high counts of mutans streptococci (greater than or equal to 10(6) CFU/ml saliva) and lactobacilli (greater than or equal to 10(5) CFU/ml saliva), both 2 and 5 months after extraction, when compared with the baseline values and with the controls . The extraction of partly erupted third molars did not appear to affect salivary yeast counts . We suggest that partly erupted wisdom teeth act as reservoirs for mutans streptococci and lactobacilli, in particular, and that their state of eruption must be taken into account when interpreting salivary microbiological counts.

Caries Res, 1990, 24(5), 312 - 7
Correlations between numbers of microflora in plaque and saliva; Mundorff SA et al.; An epidemiologic investigation to reliably identify caries-susceptible subjects by microbiological and chemical assessment of plaque and saliva is currently in progress . As part of that study, the numerical relationships of mutans streptococci, lactobacilli and total viable microflora in plaque and saliva among 12- to 15-year-old children in a fluoridated community were determined . Paraffin-stimulated whole saliva and pooled dental plaque were collected . Each sample was suspended in reduced transport fluid, chilled on ice, and assayed . The bivariate normal distribution was found to be a suitable model for the distribution of the pairs {numbers of bacteria in plaque (log10), numbers of bacteria in saliva (log10)} . Statistically significant positive correlations were found between numbers of mutans streptococci in plaque and saliva, and between lactobacilli in plaque and saliva.

Scand J Infect Dis, 1990, 22(5), 625 - 6
Treatment of bacterial vaginosis in pregnancy with a lactate gel; Holst E et al.; 10 pregnant women with bacterial vaginosis were treated vaginally with a low-pH lactate gel intermittently during 6 weeks . Reappearance of a lactobacillus-dominated vaginal flora was observed after a few days treatment in all patients . All women experienced a subjective disappearance of abnormal vaginal discharge and malodour . This local treatment restores the normal vaginal acidity and facilitates recolonization with lactobacilli . It may be preferable to oral antimicrobial therapy, especially during pregnancy.

Swed Dent J, 1990, 14(3), 131 - 5
Correlation between caries incidence and secretion rate/buffer capacity of stimulated whole saliva in 5-7-year-old children matched for lactobacillus count and gingival state; Sullivan A; The correlation between caries incidence and secretion rate/buffer capacity of stimulated whole saliva was studied in 87 children over the period from 5 to 7 years of age . Coefficients of correlation were calculated in subgroups homogenized with regard to lactobacillus count and gingival state . The highest value for saliva secretion rate was found in the subgroup with favourable values of the factors used for matching (r = 0.07) . For buffer capacity the highest value was found in the corresponding subgroup (r = -0.31) . The caries differences between groups with less favourable and favourable values of the salivary variables were also determined after elimination of the modifying effects of lactobacillus count and gingival state . The percentage difference varied between 20 and 26 . It was concluded that the saliva secretion rate and buffer capacity of saliva have a weak connection with caries incidence at this age.

Gynecol Obstet Invest, 1990, 30(2), 114 - 9
Bacterial vaginosis and the effect of intermittent prophylactic treatment with an acid lactate gel; Andersch B et al.; Intermittent treatment with an acid lactate gel (Lactal, ACO, Sweden) reduced symptoms of bacterial vaginosis (BV) and promoted the reestablishment of the normal vaginal flora of lactobacilli . Forty-two women seriously affected by recurrent BV were initially given acid gel (lactate gel, pH 3.8, 5 ml) to be inserted into the vagina daily for 7 consecutive days . Thereafter they entered into a double blind clinical trial and were treated prophylactically 3 days monthly for 6 months with either lactate gel or a placebo gel . Women treated with the lactate gel were clinically improved, i.e . no signs of BV in 88% compared to 10% in the placebo group (p less than 0.001) . The vaginal lactobacilli flora was reestablished in 83% of the lactate group and in 16% of the placebo group . Local intermittent application of lactate gel was found to be free of side effects and is a preferable alternative to repeated treatments with antibiotics in patients with recurrent BV.

Folia Microbiol (Praha), 1990, 35(3), 240 - 4
Observations on bacteria associated with pigeon crop; Shetty S et al.; Lactobacilli, streptococci and coliforms of pigeon crop contents, 5th wash, macerate and those of first-day pigeon milk have been studied . Streptococci predominated in all the samples tested . Relatively higher counts of lactobacilli and streptococci in crop macerate than in the 5th wash suggested the adhesion of these bacteria to crop wall . Because of frequent occurrence in crop of partially digested fibrous food, its contents were tested for the presence of cellulolytic bacteria . The results indicated that four isolates were capable of utilizing cellulose with the resultant production of reducing sugars . It is inferred that the crop microflora is involved in the degradation of dietary fibre in the pigeon.

Scand J Infect Dis, 1990, 22(1), 43 - 7
Effect on urogenital flora of antibiotic therapy for urinary tract infection; Reid G et al.; Specimens were examined from 70 female presenting with urinary tract infection . 50 patients were randomly treated with 7 days amoxicillin or bacampicillin and another 20 randomly received amoxicillin or enoxacin . Effective clearance of the infections was achieved with each antibiotic, and only minor side effects occurred . Bacteriological analyses of the urogenital flora demonstrated a relationship between urethral carriage and bladder infection, with Escherichia coli being the most common pathogen . Antibiotic resistant E . coli were isolated more frequently from the bladder, urethra, introitus and rectum following amoxicillin treatment compared to bacampicillin and enoxacin . An examination of the urogenital flora post therapy showed that an indigenous lactobacillus population had not been restored in the majority of patients . Rather, uropathogenic bacteria were found to dominate the urethra and introitus . The effects of antibiotics on urogenital flora is clearly a matter of importance . Future clinical trials should address this . It may be that artificial supplementation of indigenous bacteria is necessary to restore the flora back to normality.

Arch Gynecol Obstet, 1990, 247(1), 1 - 13
The role of bacterial vaginosis as a cause of amniotic fluid infection, chorioamnionitis and prematurity--a review; Martius J et al.; Antepartum bacterial vaginosis in pregnancy has been related to premature delivery, the recovery of microorganisms from amniotic fluid of women in premature labor with intact membranes, to histologic chorioamnionitis and to the recovery of microorganisms from the placenta or membranes . Microorganisms associated with bacterial vaginosis are commonly recovered from the amniotic fluid and chorioamnion of patients who deliver prematurely . In addition, bacterial vaginosis is associated with maternal infectious morbidity during labor and in the postpartum period . Very little is known of the pathophysiologic mechanisms by which bacterial vaginosis may cause preterm labor and/or premature rupture of the membranes . However, it is of interest to speculate on possible mechanisms . The high concentration of potentially pathogenic microorganisms in the vagina and cervix of pregnant women with bacterial vaginosis may increase the possibility of an ascending infection via the cervix, decidua, fetal membranes, maternal placenta, and amniotic fluid . Some of the bacteria associated with bacterial vaginosis such as Bacteroides sp . are particularly virulent . Certain bacteria produce enzymes that potentially could affect the fetal membranes or maternal deciduae . Bacteroides sp . and group B streptococcus produce proteases . Protease enzymes reduce the chorioamniotic membrane strength in vitro . It is even possible that a high concentration of bacteria in the lower genital tract could produce enough proteases to weaken the fetal membrane strength causing premature rupture of the membranes . Bacterial lipases could also produce tissue injury . Schwarz et al . demonstrated that lysosomes within fetal membrane cells contain phospholipase A2 in high concentrations . Phospholipase A2 is a precursor of prostaglandin synthesis and the destruction of lysosomes within deciduae or chorioamnion cells may induce prostaglandin synthesis resulting in uterine contractions . Bejar et al . found a high rate of phospholipase A2 production by Bacteroides sp., anaerobic streptococci, Fusobacterium sp., and G . vaginalis . Benett et al . demonstrated that bacterial products of group B streptococci, viridans streptococci, Escherichia coli and Bacteroides fragilis but not of Lactobacillus sp . increase the synthesis of prostaglandins in the membranes . Thus, selected bacteria, including some closely related to bacterial vaginosis may play a role in the initiation of uterine contractions by stimulating prostaglandin synthesis . In an alternative mechanism, either the release of prostaglandin in the membrane or uterine contraction could cause microbreaks of the membrane that allow bacterial colonization of the membrane.(ABSTRACT TRUNCATED AT 400 WORDS)

Proc Natl Acad Sci U S A, 1990 Jan, 87(2), 633 - 7
Chemical synthesis of the thymidylate synthase gene; Climie S et al.; A 978-base-pair gene that encodes thymidylate synthase (TS; 5,10-methylenetetrahydrofolate:dUMP C-methyltransferase, EC 2.1.1.45) from Lactobacillus casei has been synthesized and inserted into Escherichia coli expression vectors . The DNA sequence contains 35 unique restriction sites that are located an average of 28 base pairs apart throughout the entire length of the gene . A ribosome binding site was included 9 base pairs upstream from the translation start site and codon usage was adjusted to ensure efficient translation in E . coli . The TS gene is flanked by unique EcoRI and HindIII restriction sites that render the gene portable to any of several E . coli expression vectors . Catalytically active TS encoded by the synthetic gene is expressed in large amounts (10-20% of the soluble protein) and is indistinguishable from that isolated from L . casei . The utility of the synthetic gene for mutagenesis is demonstrated by a single experiment in which His-199 was replaced with 14 different amino acids . Analysis of the mutants by genetic complementation indicates that TS can tolerate a number of amino acid substitutions at that position and shows that His-199 is not strictly required for catalytic activity.

Zahn Mund Kieferheilkd Zentralbl, 1990, 78(8), 695 - 8
{The microbial colonization of the dentin close to the pulp in the permanent teeth following deep caries therapy}; Kneist S et al.; In a clinical microbiological study the microflora of cavity floors in 41 permanent teeth was investigated after several month of caries excavation and with or without Calxyl application on hard dentine prior sealing with zincphosphatecementum and amalgam . The cavity floors were only lowly infected . Actinomycetes or acidogenic and aciduric streptococci and lactobacilli dominated in the CFU . After application of Calxyl actinomycetes (A . israelii) were found 3-fold more frequently in the remaining population than streptococci (S . mutans) and lactobacilli . Without application of Calxyl their ratio was 1:1 . S . mutans seems to be important for the carious progression in dentin.

Arch Microbiol, 1990, 155(1), 22 - 7
Inhibition of proton-translocating ATPases of Streptococcus mutans and Lactobacillus casei by fluoride and aluminum; Sturr MG et al.; One of the major effects of fluoride on oral bacteria is a reduction in acid tolerance, and presumably also in cariogenicity . The reduction appears to involve transport of protons across the cell membrane by the weak acid HF to dissipate the pH gradient, and also direct inhibition of the F1F0, proton-translocating ATPases of the organisms, especially for Streptococcus mutans . This direct inhibition by fluoride was found to be dependent on aluminum . The dependence on aluminum was indicated by the protection against fluoride inhibition afforded by the Al-chelator deferoxamine and by loss of protection after addition of umolar levels of Al3+, which were not inhibitory for the enzyme in the absence of fluoride . The F1 form of the enzyme dissociated from the cell membrane previously had been found to be resistant to fluoride in comparison with the F1F0 membrane-associated form . However, this difference appeared to depend on less aluminum in the F1 preparation in that the sensitivity of the F1 enzyme to fluoride could be increased by addition of umolar levels of Al3+ . The effects of Al on fluoride inhibition were apparent when enzyme activity was assayed in terms of phosphate release from ATP or with an ATP-regenerating system containing phosphoenolpyruvate, pyruvate kinase, NADH and lactic dehydrogenase . Also, Be2+ but not other metal cations, e.g . Co2+, Fe2+, Fe3+, Mn2, Sn2+, and Zn2+, served to sensitize the enzyme to fluoride inhibition . The differences in sensitivities of enzymes isolated from various oral bacteria found previously appeared also to be related to differences in levels of Al.(ABSTRACT TRUNCATED AT 250 WORDS)

Caries Res, 1990, 24(5), 318 - 26
Bacteriological examination of fissure plaques from seriously mentally retarded adults; Ozeki M et al.; The microfloras of fissure plaque samples removed from a total of 23 seriously mentally retarded adults, resident in two institutions, were examined and compared with the fissure microfloras found in 17 control subjects who were employees in both institutions . The samples were collected from both an intact fissure and a fissure with brown-stained defective enamel surface of the premolars of the lower jaw . Mutans streptococci, selected with MSB medium, were recovered from only one of the defective fissures of 13 patients who became retarded younger than 2 years of age, whereas 14 defective fissures of 17 controls harbored mutans streptococci . Four of 8 patients who became retarded older than 3 years of age harbored mutans streptococci . Lactobacilli were infrequently recovered from both patients and controls . The results are discussed in terms of the microbiological aspect of caries development in adults who became mentally retarded when young.

Zahn Mund Kieferheilkd Zentralbl, 1990, 78(4), 267 - 71
{Criteria of high caries risk in the targeted preventive-curative care of 16- to 35-year-olds . The Dresden prevention study}; Klimm W et al.; Among 300 patients 16-35-yr-old 21 of them showed a high individual caries risk . Estimation of caries risk was based on the following criteria: caries experience, sugar consumption, fluoride application, dry mouth, plaque accumulation, secretion rate, buffer capacity and S . mutans and lactobacillus counts in saliva . In case of high caries risk a sure diagnosis and directed preventive-therapeutic intervention depend on a complex consideration of all the risk factors.

Med Microbiol Immunol (Berl), 1990, 179(3), 161 - 8
Augmentation of antimetastatic effect on Lewis lung carcinoma (3LL) in C57BL/6 mice by priming with Lactobacillus casei; Matsuzaki T et al.; The augmentation of the antimetastatic effect of heat-killed cells of Lactobacillus casei YIT9018 (LC9018) on Lewis lung carcinoma (3LL) in C57BL/6 mice by presensitization (priming) with LC9018 was examined . Intralesional injection of LC9018 into 3LL-bearing mice inhibited both the growth of the primary tumors and the formation of lung metastases, and this effect was significantly augmented by subcutaneous injection of LC9018 before the tumor inoculation . In the LC9018-primed mice, intraperitoneal administration of LC9018 into syngeneic hosts after priming induced a high level of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) in the peritoneal cavity . At this time, T cells of the spleen cells from the LC9018-primed mice proliferated and produced IL-2 when co-cultured with LC9018 as antigen in vitro . Also, the phenotype of these T cells was found to be L3T4+ and Ly-2.2- T cells by analysis by flow cytometry . These results suggest that LC9018-reactive helper T (Th) cells were induced by the priming and subsequent challenge with LC9018, and that IL-2 or IFN-gamma, which was produced by the activated LC9018-reactive Th cells, augmented a host immune response resulting the antitumor activity.

G Endodonzia, 1990, 4(2), 22 - 30
{Significance of the bacterial flora in the etiology of apical periodontitis . Qualitative, quantitative and topographical aspects}; Accorsi S et al.; In the international literature it is shown the central role of root canal infection in the etiology of periapical lesions . As a matter of fact it has been proved (13) that sterile necrotic pulp tissue is completely unable to cause inflammatory reactions at the periapex . Infection of endodontic origin extends to the supporting tissues of the tooth only in the case of their acute inflammation (e.g . acute apical periodontitis, acute alveolar abscess, phoenix abscess) . On the other hand in chronic inflammation bacteria remain confined in the endodontic space . Only few exceptions to this general rule have been experimentally proved . In endodontics we deal with a mixed infection which is composed by obligate anaerobes and by facultative anaerobes . The most frequently found obligate anaerobes are Bacteroides sp . and Fusobacterium sp . (Gram- rods) Anaerobic Diphtheroides (Gram+ rods) Peptostreptococcus sp . (Gram+ cocci) and Veilonella sp . (Gram- cocci) . Actinomyces sp., Lactobacillus sp., Streptococcus sp., and Staphilococcus sp . are the facultative anaerobes most frequently found.

Proteins, 1990, 8(4), 315 - 33
Plastic adaptation toward mutations in proteins: structural comparison of thymidylate synthases; Perry KM et al.; The structure of thymidylate synthase (TS) from Escherichia coli was solved from cubic crystals with a = 133 A grown under reducing conditions at pH 7.0, and refined to R = 22% at 2.1 A resolution . The structure is compared with that from Lactobacillus casei solved to R = 21% at 2.3 A resolution . The structures are compared using a difference distance matrix, which identifies a common core of residues that retains the same relationship to one another in both species . After subtraction of the effects of a 50 amino acid insert present in Lactobacillus casei, differences in position of atoms correlate with temperature factors and with distance from the nearest substituted residue . The dependence of structural difference on thermal factor is parameterized and reflects both errors in coordinates that correlate with thermal factor, and the increased width of the energy well in which atoms of high thermal factor lie . The dependence of structural difference on distance from the nearest substitution also depends on thermal factors and shows an exponential dependence with half maximal effect at 3.0 A from the substitution . This represents the plastic accommodation of the protein which is parameterized in terms of thermal B factor and distance from a mutational change.

Adv Biochem Eng Biotechnol, 1990, 42, 1 - 11
A tubular bioreactor for high density cultivation of microorganisms; Endo I et al.; By simulating the functions of the animal intestine, the authors have developed a novel tubular bioreactor (TBR) which is capable of containing both the reaction and separation of products in a single system . This reactor consisted of inorganic ultra filtration membrane modules in the primary part of the system, a heat exchanger and a recycling pump . The operation characteristics of the TBR were studied by cultivating Lactobacillus casei at a laboratory scale . The cell density obtained was up to 10 times higher than the density obtained by using the conventional jar fermentor . Furthermore, 40 g l-1 of cell mass was obtained in only 14 hours with 20 l of fresh medium when the dilution rate was increased according to the cellular growth . Afterwards, the cultivation time and the volume of fresh medium were reduced to 44% and 74%, respectively, of the values in the cultivation operation at constant dilution rate.

Adv Enzyme Regul, 1990, 30, 3 - 12
Visualization of folate transport proteins by covalent labeling with fluorescein methotrexate; Fan J et al.; Fluorescein-methotrexate (F-MTX) has been synthesized by an improved procedure and separated via chromatography on DEAE-Trisacryl into the alpha- and gamma-isomers . Purity of each isomer was verified by TLC, HPLC, and absorbance spectra . Identity of the alpha- and gamma-isomers was established by the following biological criteria: the gamma-isomer inhibited dihydrofolate reductase and was hydrolyzed by carboxypeptidase G2 (at the pteroate-glutamate linkage) . The alpha-isomer, conversely, was unreactive in both systems, which is consistent with the specificity of these enzymes . Based upon these results, the gamma-isomer was selected for covalent labeling of proteins . Fluorescent bands were observed when the 22 kDa human dihydrofolate reductase and the 18 kDa folate transporter from Lactobacillus casei were treated with gamma-F-MTX (activated by N-hydroxysuccinimide) and subjected to SDS-PAGE . The probe was also useful for visualizing in situ the micromolar folate transport protein in L1210 cells.

Int J Food Microbiol, 1990 Jan, 10(1), 51 - 7
Utilization of sugars by Lactobacillus acidophilus strains; Srinivas D et al.; Utilization of various carbohydrates viz., glucose, fructose, sucrose, lactose and galactose by Lactobacillus acidophilus strains was investigated in Lactobacillus Selection Broth . Maximum viable counts, acid production and sugar utilization by different test strains were in the order: glucose greater than or equal to fructose greater than sucrose greater than or equal to lactose greater than galactose . The generation time of the tested strains was shorter in glucose medium as compared to sucrose or lactose medium.

Microbiol Immunol, 1990, 34(5), 471 - 5
Electron microscope studies on the intracellular growth of PL-1 phage of Lactobacillus casei; Watanabe K et al.; Ultrathin sections of the cells of Lactobacillus casei infected with or without PL-1 phages were observed by the rapid-freezing and substitution-fixation method . Phage-head-like particles were first observed in the nuclear region . The region was seen more widely dispersed in the cytoplasm than that observed by the conventional chemical fixation method . The features of cells just broken open by the infected phages were observed by the sedimentation method devised by us . The bursting occurred in more than one place in the cells with liberation of progeny phages.

Cancer Chemother Pharmacol, 1990, 26(4), 273 - 7
Inhibition of thymidylate synthase by the diastereoisomers of leucovorin; Lee PP et al.; The clinical formulation of leucovorin (5-CHO-FH4) is a mixture of diastereoisomers with markedly different pharmacologic properties . Comparatively little information is available concerning the cellular pharmacology of reduced folate stereoisomers, due largely to the difficulty in preparing sufficient quantities of these compounds for in vitro use . Recent improvements in HPLC technology have now facilitated this process, enabling studies of folate stereochemistry on a larger scale . Using purified (6R) and (6S) leucovorin, we examined the effects of these compounds on the enzymatic activity of Lactobacillus casei thymidylate synthase (TS) in a cell-free system . The natural (6S), unnatural (6R), and racemic (6R,S) leucovorin preparations inhibited TS activity by 50% at concentrations of 0.11, 2.1, and 0.52 mM, respectively . Dixon plots demonstrated the inhibition to be competitive, with Ki values of 85 microM, 1.59 mM, and 385 microM for (6S), (6R), and (6R,S) leucovorin, respectively . In view of the high doses of leucovorin given clinically and the slow clearance of the unnatural isomer, our observations suggest that leucovorin may have important direct inhibitory effects on folate-requiring enzymes.

Vestn Dermatol Venerol, 1990, (2), 72 - 5
{Acute Lipschütz-Chapin vulvar ulcer}; Kovalev VM et al.; A 17-year-old female patient is described, who had a sexual intercourse, the only in her life, a year before . Hectic temperature has developed in the presence of an exacerbation of chronic decompensated tonsillitis; the general status has essentially deteriorated . A sharply painful ulcer, up to 2 cm in diameter, was seen on the lower third of the involved labium majus; Lactobacilli casei were isolated from the discharge from this ulcer . After 2 weeks of antibiotic and immunocorrective therapy a delicate atrophic cicatrix has formed . The factors that helped diagnose the Lipschutz-Chapin acute vulvar ulcer were exacerbation of a chronic focal infection, anemia, leucocytosis, thrombocytopenia, dysproteinemia, and disordered cellular and humoral immunity.

Caries Res, 1990, 24(2), 107 - 12
Effect of pH on acid production from sorbitol in washed cell suspensions of oral bacteria; Kalfas S et al.; The acid production from sorbitol and glucose was studied under anaerobic conditions in resting cell suspensions of bacteria from the predominant sorbitol-fermenting human dental plaque flora, belonging to the genera Streptococcus, Lactobacillus and Actinomyces . The acid production activity of the bacterial cells was followed by titration with alkali, at environmental pH 7.0, 6.0 and 5.0 after addition of carbohydrate solution . The metabolic end products formed in the suspensions were analyzed thereafter by isotachophoretic and enzymatic methods . The results showed that sorbitol was fermented at a slower rate than glucose . Lowering the environmental pH decreased the acid production activity from the two carbohydrates . Compared with glucose, the catabolism of sorbitol was affected to greater extent by the pH conditions . The total amount of acids formed from sorbitol was considerably less than from glucose . Lactic acid, which was the major end product in glucose-challenged suspensions, was produced only in low concentrations from sorbitol by all strains tested . The ratio strong (formic + lactic)/weak acids was moreover lower for sorbitol than for glucose . The present results further illustrate some of the mechanisms behind the low cariogenic potential of this sugar substitute.

Microbios, 1990, 62(250), 37 - 46
Evidence for the involvement of thiocyanate in the inhibition of Candida albicans by Lactobacillus acidophilus; Jack M et al.; Lactobacillus acidophilus has been found to inhibit Candida albicans when grown on MRS agar plates . Attempts to isolate an active factor responsible for this inhibition from liquid culture and agar plates were not successful . The addition of sodium thiocyanate to the agar was found to increase the inhibition offered by the lactobacillus . The results indicate that hydrogen peroxide produced by the lactobacillus is being used to convert the thiocyanate to hypothiocyanate which is more toxic . The involvement of a lactobacillus peroxidase in this conversion is postulated.

J Biomed Mater Res, 1990 Jan, 24(1), 39 - 46
Exclusion of uropathogen adhesion to polymer surfaces by Lactobacillus acidophilus; Hawthorn LA et al.; The ability of bacteria to adhere to surfaces is a major cause of concern in the use of biomaterial substrates . The adhesion of Staphylococcus epidermidis strain 1938 was examined using image analysis and was found not to correlate with polymer surface tension, unlike that of Lactobacillus acidophilus, which adhered to more hydrophobic polymers . A fimbriated uropathogenic E . coli strain showed very low levels of adherence to the biomaterials . Precoating the polymers with lactobacilli significantly reduced the staphylococcal and E . coli adhesion, a result which could have clinical significance . An additional finding was that the interaction of staphylococci and E . coli with lactobacilli coated polymers altered the adhesion profile of the latter . Lactobacilli appeared to detach from polymers of low surface tension and reattach to polymers with high surface tensions . This resulted in the highest levels of exclusion of uropathogens being found for lactobacilli-coated glass and sulfonated polystyrene, both of which are hydrophilic (with high surface tensions) . These results demonstrate that lactobacilli can be used to coat biomaterial surfaces leading to a reduced adhesion of uropathogens.

Eur J Obstet Gynecol Reprod Biol, 1990 Jan-Feb, 34(1-2), 171 - 8
Treatment failure in trichomoniasis and persistence of the parasite after Lactobacillus immunotherapy; two case reports; van der Weiden RM et al.; This report describes the clinical and laboratory observations on two patients with a Trichomonas vaginalis infection resistant to metronidazole . The metronidazole resistance was confirmed in in vitro cultures under aerobic conditions, after in vitro cultivation of the strains . Trichomonas infection persisted during high-dose intravenous metronidazole administration and Lactobacillus immunotherapy was unsuccessful in both patients.

Ankara Univ Hekim Fak Derg, 1990 Jan, 17(1), 23 - 9
{Investigation of the microbiological variations at the empty root canals after retrograde histoacryl filling that is made with pulpectomy at the same time}; Harputluoglu S et al.; Many researchers defended the thesis of eradicating the apical foramen microleakage for a successful root canal treatment . This study has been designed to defect whether microorganisms will grow or not at the empty root canals as a result of the perfect obstruction of the apical foramen with histoacryl of least microleakage retrogradely . The study has been realized on 24 teeth of 6 adult dogs . Histoacryl was used to obstruct the apical foramens and the experimental animals were anesthetized with general anesthesia . Experimental animals were divided into three groups before the operation . At each group, eight teeth of two experimental animals were studied on . Consequently, a great amount of streptococcus kind, lactobacillus and staphylococcus were isolated at the cultures taken from the root canals of 15 days cases . At 30 day cases, peptostreptococus, lacto bacillus and staphylococcus were isolated while at 60 day cases streptococcus pneumonia, and lactobacillus were isolated and evaluated as meaningless.

Acta Vet Hung, 1990, 38(1-2), 3 - 17
Feeding trial in pigs with a diet containing sodium n-butyrate; Galfi P et al.; Pigs weighing 7 to 102 kg were fed a diet containing 0.17% sodium n-butyrate . The diet increased the average daily body mass gain of pigs by 23.5% . Due to its dietetic effect, feed consumption increased by 8.9% . However, owing to the higher feed conversion, specific feed utilization was reduced by 11.8% . The experimental diet markedly reduced the percentile proportion of coliform bacteria in the ileum as compared to Lactobacillus ssp.: it decreased the coliform count and increased the counts of Lactobacillus spp . The diet increased the length of ileal microvilli and the depth of caecal crypts . It raised the concentration of immunoreactive insulin in the blood plasma . The feed supplemented with sodium butyrate did not alter adversely the clinical indices tested . It reduced feed costs by 9% and increased the returns from sales by 13% . As the additive is normally produced by microbial fermentation in the large intestine, it is not alien to the body . Sodium butyrate exerted its favourable effect in 3.6- to 24.2-fold lower concentrations than the organic acids (citric acid, fumaric acid, propionic acid) used earlier . With respect to its favourable biological and economic effect, sodium n-butyrate can be recommended for use in pig feeding as a growth promoter.

Swed Dent J, 1990, 14(6), 261 - 6
Dental caries in players belonging to a Swedish soccer team; Ljungberg G et al.; Since dental caries is associated with frequent use of sugar-containing products and since there is a potential risk for such a consumption among sportsmen, we conducted a clinical study of a group (n = 30) of 17-30-year old elite soccer players, including DFS and various caries-related factors, such as plaque index, numbers of cariogenic microorganisms in saliva and sugar intake frequency . Each player was asked to identify one friend of the same age, sex and social background but not active in any sport (n = 28) . The mean values for DFS, plaque index, mutans streptococci and lactobacilli were less favourable for the players, but none of the differences were statistically significant, except for the dietary score (p less than 0.05) . Thus, soccer players on an elite level seem to have a somewhat higher risk to develop dental caries than nonplayers . However, their regular use of fluoride-containing toothpaste probably to some part compensates for this increased risk.

Arch Oral Biol, 1990, 35 Suppl, 213S - 215S
The approximal bone height and intrabony defects in young adults, related to the salivary buffering capacity and counts of Streptococcus mutans and Lactobacilli; Wikner S et al.; Using a computerized technique the bone height and prevalence of approximal periodontal intrabony defects were assessed on posterior bite-wing radiographs from 151 young adults . The results were related to the buffering capacity and counts of Streptococcus mutans and lactobacilli in whole stimulated saliva . The mean distance from the cement-enamel junction to the alveolar bone crest was greater in the high buffering group than in the low buffering group (p less than 0.05), and particularly in non-smokers (p less than 0.01) . Intrabony defects were more common in the low buffering group (p less than 0.05) and in women (p less than 0.001).

Arch Oral Biol, 1990, 35 Suppl, 173S - 175S
Associations between salivary levels of mutans streptococci, lactobacilli, yeasts and black-pigmented Bacteroides spp . and dental variables in elderly dental patients; Beighton D et al.; Multivariate step-wise regression analyses demonstrated that in a population of 146 elderly dental patients (mean age 69.8 yr) the salivary level of mutans streptococci was unrelated to the root DFS score, unlike the levels of lactobacilli and yeasts . Mutans streptococci were related to the wearing of partial dentures and the number of snacks eaten per day, while salivary lactobacillus levels were also related to the number of snacks eaten per day and to denture wearing, and negatively related to saliva buffering . Salivary yeast levels were also related to the wearing of partial dentures and the number of snacks eaten per day, and negatively related to salivary neuraminidase activity . The R2 values ranged from 0.21 to 0.28 . Salivary level of black-pigmented Bacteroides spp . were related to maximum CPITN score, mean bleeding index and salivary trypsin-like activity (R2 was 0.08).

J Pedod, 1990 Spring, 14(3), 141 - 3
Clinical and microbiological caries-risk parameters at different stages of dental development; Schlagenhauf U et al.; Caries incidence and activity in general are not linear functions, but show several intensity peaks at different stages of life . The purpose of this study was to evaluate, whether the transition from the primary to the permanent dentition is accompanied by any significant changes in several clinical and microbiological parameters commonly used as predictors of caries activity . Sixty children and adolescents, aged 3 to 16, participated in the study and according to age were assigned to 4 different dentition groups (primary, early mixed, late mixed, permanent) . The results indicate, that there is a significant decrease in salivary Streptococcus mutans and Lactobacillus spp . counts in the late mixed dentition group compared to the primary and the early mixed dentition group . Furthermore, in the permanent dentition group the stimulated salivary flow rate was significantly higher than in all other groups . Differences regarding plaque score and salivary buffering capacity were not significant for all groups examined . It is concluded, that the transition from the primary to the permanent dentition in general is accompanied by significant, yet temporary decline in the numbers of caries-associated microorganisms, reflecting marked differences in caries incidence and activity, previously reported by other authors.

Caries Res, 1990, 24(1), 23 - 9
A method for the identification of Streptococcus mutans in gingival margin plaque by immunofluorescence; Bush MS et al.; A method was developed to identify Streptococcus mutans in natural dental plaque by indirect immunofluorescence staining, using a high-titred polyclonal antiserum raised against a serotype c strain of S . mutans followed by an FITC conjugate . Specificity was determined by staining 45 representative strains of plaque organisms, which demonstrated minimal cross-reactions . In vitro incubation of S . mutans NCTC 10449 films with a human serum containing antibodies to S . mutans and the presence of extracellular polysaccharide did not inhibit staining . The staining method enabled 98% of the streptococci to be detected in mixtures of S . mutans NCTC 10449 and Lactobacillus casei NCTC 10302 . S . mutans was detected at a ratio of 1:100,000 in mixtures of pure cultures . In plaque samples, S . mutans could be distinguished from other organisms, including an unidentified cross-reacting bacillus found in some gingival plaque samples . The results suggest that immunofluorescence is a fast, practical method for identifying specific bacteria in plaque and, therefore, could be of use in microbiological studies of caries.

Gene, 1989 Dec 21, 85(1), 259 - 65
The molecular cloning, sequence and expression of the hdcB gene from Lactobacillus 30A; Copeland WC et al.; We previously cloned the structural gene hdcA, which encodes the enzyme histidine decarboxylase (HDC; EC 4.1.1.22), from Lactobacillus 30a and found what appeared to be the start of a second gene 59 nucleotide (nt) downstream from the hdcA stop codon {Vanderslice et al., J . Biol . Chem . 32 (1986) 15186-15191} . Here we report the complete nt sequence of this second gene, which we have named hdcB, and show that it encodes a 20-kDa protein, HDCB, which was purified from Escherichia coli . The hdcA and hdcB genes together comprise an operon, the transcription from which is shown to be increased threefold by the presence of histidine in the growth medium . Western blots were used to quantitate the rise in concentrations of both gene products during histidine induction of the hdc operon . This increase was found to be proportional to the observed threefold increase in the concentration of the respective mRNAs . Transcription of the hdc operon in the mutant-3 strain of Lactobacillus 30a {Recsei and Snell, Biochemistry 12 (1973) 365-371} was shown to be constitutively 15-fold greater than in uninduced wild type cells and was unaffected by histidine . The transcription start point was defined as a guanine 73 nt 5' to the start codon of the hdcA gene . Of the transcripts initiated at this promoter, 15% include both hdcA and hdcB sequences, the remainder terminate in the intergenic region and thus encode only hdcA.

Gene, 1989 Dec 21, 85(1), 253 - 8
Characterization of a cryptic plasmid from Lactobacillus plantarum; Bates EE et al.; The complete nucleotide sequence of pLB4, a cryptic plasmid isolated from Lactobacillus plantarum NCDO1088 has been determined . Three open reading frames, which encode proteins of 42, 25 and 6 kDa, have been identified . In vitro transcription/translation of pLB4-derived DNA restriction fragments confirm the existence of all three polypeptides, which show homology to replication proteins and site-specific recombinases from other Gram+ plasmids . Three major regions of dyad symmetry with delta G of -28.8, -15.0 and -17.0 kcal were observed . One of these regions contains a sequence which shows perfect homology to the nick site of the Gram+ replicons, pE194, pLS1 and pADB201 . In addition, a 21-bp sequence located upstream from the site-specific recombinase shows 80% homology to the recombination sites of pE194 and pT181.

Community Dent Oral Epidemiol, 1989 Dec, 17(6), 285 - 8
Prediction of caries activity in children with today's low caries incidence; Klock B et al.; One hundred 14-yr-old children were observed over 1 yr to find out if caries incidence and caries progression could be predicted in a low prevalence child population by means of well-known caries related factors . The mean caries incidence was low (0.45, SD 0.70) but, on the other hand, 32% of the children developed at least one new lesion during the test period . In only eight out of 35 children progressing lesions were demonstrated . Independent variables at baseline examination were caries prevalence, sucrose intake, fluoride exposure, oral hygiene, saliva secretion rate, and salivary concentrations of mutans streptococci and lactobacilli . A weak but statistically significant correlation was demonstrated between caries incidence and caries prevalence . No other significant correlations were shown . It was concluded that caries activity could not be predicted in this population . Low disease prevalence was a major reason for the weak correlations.

Oral Microbiol Immunol, 1989 Dec, 4(4), 230 - 2
Salivary levels of putative cariogenic organisms in patients with eating disorders; Bretz WA et al.; The present study examined the hypothesis that women with eating disorders associated with a history of chronic vomiting can be characterized by a salivary flora with high levels of aciduric organisms, such as, mutans streptococci, lactobacilli and yeast . Three groups of female subjects were studied: vomiting bulimics (G1; n = 14), and comparison groups selected for high Streptococcus mutans (G2; n = 13), and low S . mutans levels (G3; n = 12) . The prevalence and levels of mutans streptococci, lactobacilli and yeast tended to be higher in bulimics than in non-bulimics . The bulimics had significantly higher levels and higher prevalence of Streptococcus sobrinus than the non-bulimics . A high S . sobrinus colonization may be a marker for a history of vomiting in bulimia.

Av Odontoestomatol, 1989 Dec, 5(10), 695 - 9
{Evaluation of in vitro adhesion of cariogenic microorganisms to enamel and dental filling materials}; Casas I et al.; The adhesive ability of Lactobacillus, Streptococcus mutans and Actinomyces viscosus-naeslundii on enamel, amalgam and composite of microparticle and small-particle are studied "in vitro" . The selective mediums used for the three micro-organisms are, respectively, Rogosa agar, M.S.B . and C.F.A.T . The lower adherence is showed by bacterias of Lactobacillus genus . S . mutans and A . viscosus-naeslundii show similar adherence properties between them . The greatest adherence was obtained in composites, being S . mutans the bacteria with a greatest level of adherence to the composites of small-particle, and A . viscosus-naeslundii the bacteria with more adherence to the ones of micro-particle . The adherence on amalgam was slightly lower than the adherence on enamel.

J Dent Res, 1989 Dec, 68(12), 1734 - 8
The microflora associated with the development of initial enamel decalcification below orthodontic bands in vivo in children living in a fluoridated-water area; Boyar RM et al.; Thirty-four caries-free teeth destined for orthodontic extraction were banded to provide a protected area for the accumulation of plaque . The teeth were extracted at one, two, four, eight, and 14 days after being banded, and samples of the flora below the band were analyzed for the presence of Streptococcus sanguis, Streptococcus 'mitior', 'mutans streptococci', Actinomyces viscosus, Actinomyces naeslundii, Actinomyces odontolyticus, Lactobacillus species, and Veillonella . After plaque sampling, the teeth were sent to the Royal Dental College (Copenhagen) for histological analysis . The results showed that S . mutans could colonize the area below the band after one day, but that colonization was only 100% at 14 days . Lactobacillus was only isolated from 2/8 samples at four days and from 4/8 samples at 14 days . S . sanguis and 'S . mitior' were regularly isolated at all banding times, and Veillonella was isolated from all samples . A . viscosus was the most commonly isolated Actinomyces . The numbers of Streptococcus and Veillonella were significantly higher at day 1 than at day 14 (p less than 0.05) . S . mutans and A . viscosus were isolated more frequently at day 14 than at day 1 (p less than 0.01) . Histological examination revealed that dissolution of the enamel below a band could occur after two days, but that even after 14 days dissolution could be questionable . Dissolution was detected in areas where S . mutans was not isolated (8/34), but S . mutans was also present in samples showing dissolution (12/34) . There was no relationship between dissolution and the numbers of S . mutans; however, the isolation frequency of S . mutans was associated with dissolution (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

J Bacteriol, 1989 Dec, 171(12), 6455 - 67
A phylogenetic analysis of the mycoplasmas: basis for their classification; Weisburg WG et al.; Small-subunit rRNA sequences were determined for almost 50 species of mycoplasmas and their walled relatives, providing the basis for a phylogenetic systematic analysis of these organisms . Five groups of mycoplasmas per se were recognized (provisional names are given): the hominis group (which included species such as Mycoplasma hominis, Mycoplasma lipophilum, Mycoplasma pulmonis, and Mycoplasma neurolyticum), the pneumoniae group (which included species such as Mycoplasma pneumoniae and Mycoplasma muris), the spiroplasma group (which included species such as Mycoplasma mycoides, Spiroplasma citri, and Spiroplasma apis), the anaeroplasma group (which encompassed the anaeroplasmas and acholeplasmas), and a group known to contain only the isolated species Asteroleplasma anaerobium . In addition to these five mycoplasma groups, a sixth group of variously named gram-positive, walled organisms (which included lactobacilli, clostridia, and other organisms) was also included in the overall phylogenetic unit . In each of these six primary groups, subgroups were readily recognized and defined . Although the phylogenetic units identified by rRNA comparisons are difficult to recognize on the basis of mutually exclusive phenotypic characters alone, phenotypic justification can be given a posteriori for a number of them.

Community Dent Oral Epidemiol, 1989 Dec, 17(6), 292 - 5
Caries prevalence, Streptococcus mutans and sugar intake among 4-year-old urban children in Iceland; Holbrook WP et al.; Concern at the high prevalence of dental caries in Iceland prompted this survey of 158 preschool children in Reykjavik . On initial examination in 1987 45.8% of the children were caries-free and the prevalence of caries was a mean dmft 2.4 and a mean dmfs 3.3 . A dietary questionnaire aimed at discovering the frequency of sugar consumption per week revealed a threshold value of 30 instances of sugar intake per week above which caries prevalence increased markedly . Some of this sugar is consumed in paediatric medicines, particularly antibiotics and anti-asthmatics, which are widely used in Iceland . Caries prevalence (dmft) for children taking such medicines regularly was 3.0 compared with 2.1 for remaining children (P less than 0.05) . Those children who took fluoride tablets regularly had less caries (mean dmft 1.1) than those who used fluoride tablets irregularly or not at all (mean dmft 2.8; P less than 0.001) . Samples of saliva from the dorsum of the tongue were taken for determination of numbers of Streptococcus mutans and lactobacilli . High bacterial counts were strongly associated with caries . Only 5% of children with more than 5 x 10(5 S . mutans cfu per ml were caries free but 27% of subjects had 67% of the total amount of caries for the group and all of these would have been detected by the bacterial test.

Mycopathologia, 1989 Dec, 108(3), 173 - 8
Fungispecificity of fluconazole against Candida albicans; Liss RH et al.; Candida albicans is an opportunistic pathogen of human mucosal surfaces . Colonization of oral and vaginal mucosa by this yeast is antagonized by the resident normal bacterial population . However, antibacterial therapy can alter the normal flora to allow fungal cells to attach, grow and invade host tissues . We studied the antimicrobic activity of fluconazole against clinical isolates of oral and vaginal bacteria and Candida albicans in vitro and in vivo by scanning and transmission electron microscopy; we also compared the bactericidal activity of fluconazole with clotrimazole in vitro by microbiologic assay . Fluconazole lysed fungi but did not change the ultrastructure of bacteria . Clotrimazole, but not fluconazole, was bactericidal against lactobacillus and streptococcus, the principal species of the oral and vaginal cavities . We conclude that Candida albicans, but not oral and vaginal bacteria, is susceptible to fluconazole . These observations help explain the antimycotic specificity of fluconazole and its efficacy against candidiasis in humans.

Endod Dent Traumatol, 1989 Dec, 5(6), 266 - 73
Some effects of Ledermix paste and Pulpdent paste on mouse fibroblasts and on bacteria in vitro; Taylor MA et al.; Dilutions of Ledermix paste, Pulpdent paste and a mixture of equal parts by weight of Ledermix paste and Pulpdent paste were added to in vitro cultures of mouse fibroblasts or bacteria for 24 h, and various cell functions were then examined: mitosis in and survival of fibroblasts, and survival of Lactobacillus casei or Streptococcus mutans . Ledermix was found to reversibly inhibit mitosis while present in the concentrations range 10(-3) to 10(-6) mg/ml . Mixing with Pulpdent did not modify this antimitotic effect . Ledermix killed mouse fibroblasts at 10(-3) mg/ml and above, while Pulpdent killed at 1 mg/ml and above . The toxic effect of Ledermix was slightly inhibited by mixing it with Pulpdent . Ledermix killed S . mutans at about the same concentration at which it killed the mammalian cells, but required a one thousand-fold greater concentration to kill L . casei . Pulpdent killed both L . casei and S . mutans at approximately one-fifth of the concentration at which it killed the mammalian cells . Pulpdent slightly potentiated the antibacterial effect of Ledermix . The pH of Pulpdent was reduced by approximately 0.3 units by mixing with Ledermix . The present data showed that the 50:50 mix of Ledermix and Pulpdent retained the properties examined that are thought to be of therapeutic benefit, while not increasing the toxicity of the component parts to mammalian cells.

Jpn J Cancer Res, 1989 Dec, 80(12), 1238 - 45
Effect of combined intrapleural administration of Lactobacillus casei (LC9018) and adriamycin on experimental malignant pleurisy in mice; Tohgo A et al.; The combined effect of Lactobacillus casei YIT9018 (LC9018) and adriamycin (ADR) on malignant pleurisy was investigated using an experimental model in BALB/c mice in which Meth A fibrosarcoma cells were intrapleurally implanted . The control mice died from dyspnea due to pleural effusion, before significant growth of tumor nodules could be achieved in the thoracic cavity . Intrapleural (ipl) administration of LC9018 (20-200 micrograms/head) on days 1 and 5 reduced the effusion volume and induced pleural adhesions in a dose-related manner . A statistically significant and reproducible prolongation of survival was observed at a dose of LC9018 200 micrograms/head: increase of lifespan (ILS) values of 15-39% were obtained . An ipl administration of ADR (2-4 mg/kg) on day 1 was also effective in prolonging survival without severe toxicity (ILS values of 100-122%) . The combined use of ADR and LC9018 induced a high incidence of pleural adhesions, a delay in effusion accumulation, and an additive prolongation of lifespan (ILS values of 133-178%), compared with ADR monotherapy . In the combination therapy group, a marked and continuous ipl exudation of neutrophils, macrophages, and lymphocytes was observed with a significant decrease in pleural tumor cells . These findings suggest that ipl administration of LC9018 enhances the effect of ADR, probably through both host-mediated tumoricidal activity and sclerosing effects on the pleura.

Vet Microbiol, 1989 Dec, 21(2), 155 - 63
Bacterial growth in mastitic whey in relation to bacterial association with mastitis; Kaartinen L et al.; The growth of mastitis pathogens (eight strains) and non-pathogenic bacteria (eight strains) was studied using microturbidometry . All bacteria grew well in whey originating from uninflamed quarters . However, the growth of bacteria which are not considered to be mastitis pathogens (Lactobacillus plantarum, Bacillus subtilis, Streptococcus lactis and Pseudomonas fluorescens) became suppressed by whey from mastitic quarters . On the contrary, the growth of Staphylococcus aureus and Escherichia coli was generally better in mastitic samples . Streptococcus agalactiae showed inconsistent results.

Mutat Res, 1989 Dec, 224(4), 493 - 502
Mutagenic activity of various kinds of cheese on the Ames, rec and umu assays; Yamaguchi T; Some kinds of cheese were found to be mutagenic when some inhibiting substances were removed through extraction with MeOH-H2O and then treated with ion exchange resin . After this procedure, 16 types of commercial cheese out of 45 types tested showed significant mutagenicity on Salmonella typhimurium TA104, TA102 and TA97 without S9 mix . Almost all of these cheese also showed genotoxicity on the rec assay and the umu assay . The appearance of mutagenicity in these cheeses seemed to be related to the type of aging during the production process; most of the cheeses with high potency belonged to the blue mold and Propionibacteria-type cheeses and only a few belonged to the white mold, Lactobacillus-type or fresh-type cheeses . The substances inhibiting mutagenicity were isolated and identified as long-chain fatty acids.

Gene, 1989 Nov 30, 83(2), 263 - 70
Cloning, sequencing and expression of the L-2-hydroxyisocaproate dehydrogenase-encoding gene of Lactobacillus confusus in Escherichia coli; Lerch HP et al.; The gene (L-HicDH) encoding L-2-hydroxyisocaproate dehydrogenase (L-HicDH) from Lactobacillus confusus was cloned in Escherichia coli . A 69-mer oligodeoxyribonucleotide probe, derived to be complementary to the N-terminal amino acid (aa) coding sequence, was used for screening . The complete nucleotide (nt) sequence of the L-HicDH gene was determined . The 5'-end of the mRNA was mapped by primer extension and the promoter identified . Downstream from the L-HicDH gene is a typical Rho-independent terminator . The aa sequence of L-HicDH, deduced from the nt sequence, has an overall similarity of 30% to the aa sequence of L-lactate dehydrogenase (L-LDH) from Lactobacillus casei . The aa residues involved in binding of coenzyme and substrate are highly conserved in L-HicDH with respect to prokaryotic and eukaryotic L-LDHs . The L-HicDH gene could be expressed under control of phage lambda 'Leftward' and 'rightward' promoters in E . coli up to 35% of total cell protein . The enzyme produced under these conditions exhibits full specific activity and is found exclusively in soluble form.

Am J Clin Nutr, 1989 Nov, 50(5), 1059 - 63
Rapid uptake and clearance of pyridoxine by red blood cells in vivo; Anderson BB et al.; There is rapid pyridoxine (PN) uptake in vitro into red cells where it is converted to pyridoxal (PL) forms . To assess uptake in vivo, the equivalent of 48.6 and 118 mumol PN were given intravenously to a healthy female subject . Vitamin B-6 compounds were measured by a Lactobacillus casei microbiological assay in blood taken 1-60 min after injection . After either injection there was a considerable amount of PN in the red cells at 1 min but by 3 min a large amount of that PN had disappeared, mostly unaccounted for by conversion to PL forms . Although there was considerably less PN at 1 min in both red cells and plasma after the smaller injection, in the next 2 min similar amounts had left the red cells (4.59 and 4.30 mumol) and plasma (9.37 and 10.09 mumol), respectively, after the injections . Red cells, as well as plasma, may be transporting PN to other sites of metabolism in tissues.

Plasmid, 1989 Nov, 22(3), 193 - 202
Characterization, cloning, curing, and distribution in lactic acid bacteria of pLP1, a plasmid from Lactobacillus plantarum CCM 1904 and its use in shuttle vector construction; Bringel F et al.; A small 2.1-kb plasmid called pLP1 was extracted from Lactobacillus plantarum CCM 1904 (ATCC 8014) and cloned into the Escherichia coli pUC19 plasmid . As determined by DNA-DNA Southern hybridization with a pLP1-radioactively labeled probe, other lactic acid bacteria such as L . curvatus, L . sake, Carnobacterium, and Leuconostoc mesenteroides harbor pLP1-related plasmids . Shuttle vectors based on the pLP1 replicon were constructed by inserting the erythromycin-resistance gene from pVA891 into the various pUC19-pLP1 constructions . pLP1-based shuttle vector transformation efficiencies (TE) by electroporation were compared to TE of a broad-host-range plasmid pGK12 in different lactobacilli strains . Expression of the pUC19-pLP1 plasmids in Escherichia coli maxicells showed that pLP1 encodes for a 37,000 MW protein which can act in trans allowing the replication of plasmids in which this protein is truncated . The pLP1-based shuttle vectors producing this protein replicate in lactobacilli and also in Bacillus subtilis . A pLP1-free strain was obtained by incompatibility with a pLP1-based shuttle vector introduced in L . plantarum CCM 1904 by electroporation . The absence of pLP1 has no incidence on the strain phenotype suggesting that pLP1 is not essential for the strain in our laboratory conditions.

Int J Food Microbiol, 1989 Nov, 9(3), 237 - 47
Shelf-life of vacuum-packed cooked ring sausages at different chill temperatures; Korkeala H et al.; Microbiological and sensory changes in 313 vacuum-packed cooked ring sausages from 28 different production runs and stored at 2, 4, 8 or 12 degrees C were monitored as a function of time . The sensory scores started to decrease at a level of approx . 10(7) lactobacilli/g . The judges began considering the samples unfit for human consumption when the lactobacilli counts were between 10(7) and 10(8) cfu/g; above a level of 10(8) cfu/g most of the samples were deemed unfit . At 2 degrees C, however, spoilage did not always seem to be microbiological, and four out of six different production runs were deemed unfit without any marked increase in microbial counts . In such cases, the judges described the sensory defects as a 'musty' rather than a sour aroma and taste . The sausages were deemed unfit when the lactobacilli were in a stationary growth phase which was considerably later than the point when the bacterial counts exceeded 10(7) cfu/g . The mean length of this delay was 30, 19, 16 and 7 days at 2, 4, 8 and 12 degrees C, respectively . The average shelf-lives were 55, 43, 29 and 17 days at 2, 4, 8 and 12 degrees C, respectively . The dependence of shelf-life on temperature can be formulated as follows: Shelf-life = 10(1.835 - 0.048 X temperature) The maximal shelf-life of this product, including nonmicrobiological spoilage, is assessed as approx . 10-11 weeks . A lactobacilli count greater than 10(7) cfu/g indicates that either the spoilage process has started or the product is already spoiled . When the lactobacilli count exceeds 10(8) cfu/g it is highly probable that the sausage sample is unacceptable.

Chem Pharm Bull (Tokyo), 1989 Nov, 37(11), 3026 - 8
Superoxide dismutase activity in some strains of lactobacilli: induction by manganese; Gonzalez SN et al.; Dialyzed cell-free extract of lactobacilli was found to contain superoxide dismutase activity by using a test system in which superoxide ion is generated by xanthine oxidase . The specific activities of Lactobacillus acidophilus ATCC 4356, Lactobacillus murinus ATCC 35020, Lactobacillus acidophilus CRL 358, Lactobacillus plantarum ATCC 8014, Lactobacillus casei CRL 431, Lactobacillus plantarum CRL 353, Lactobacillus fermentum ATCC 9338, Lactobacillus buchneri NCDO 110, and Lactobacillus fermentum CRL 251 were between 0.06 and 0.43 U/mg protein . The presence of superoxide dismutase activity was demonstrated when the strains were grown in media containing Mn2+ ions . Superoxide dismutase of lactobacilli may be an Mn enzyme since it was not inhibited by either cyanide or azide ions . However, the cell-free extract of Lactobacillus murinus ATCC 35020 contains superoxide dismutase activity sensitive to both ions.

Arch Exp Veterinarmed, 1989 Nov, 43(6), 835 - 41
{Long-term cryopreservation of microbial strains relevant to food hygiene}; Beutling D; Experiments on long-time cryopreservation at -20 degrees C were conducted, using 42 microbial strains of relevance to food hygiene . Blood slant agar was coated with 10% glycerol solution, so that all strains were in re-culturing conditions, following 12 months of storage . Re-culturing of 18 in 20 of the microbial genera used in the experiment was possible after 24 months of storage, if strains had been kept only in 10% glycerol solution . The method proved suitable particularly for strain keeping of highly sensitive genera (Lactobacillus, Pseudomonas, Aeromonas, Shigella).

Antimicrob Agents Chemother, 1989 Nov, 33(11), 2016 - 8
In vitro susceptibilities of oral bacterial isolates to spiramycin; Chan EC et al.; Four hundred strains of oral bacteria were tested for their susceptibility to spiramycin . Actinobacillus actinomycetemcomitans and most species of Lactobacillus were resistant to the antibiotic . All strains of cariogenic Streptococcus mutans and most strains of bacterial species implicated in adult chronic periodontitis (Bacteroides gingivalis, B . intermedius, and Treponema denticola) were susceptible to spiramycin.

Plasmid, 1989 Nov, 22(3), 236 - 43
Tn917 transposition in Lactobacillus plantarum using the highly temperature-sensitive plasmid pTV1Ts as a vector; Cosby WM et al.; pTV1Ts, a temperature-sensitive plasmid coding for chloramphenicol (Cm) resistance and carrying the macrolide-lincosamide-steptogramin B (MLS) resistance transposon Tn917, was introduced into strains of Lactobacillus plantarum by electroporation . After two passages in broth medium selecting for MLS resistance at 40 degrees C and subsequent plating on solid medium, two strains, L . plantarum NC4Ts1 and L . plantarum NC7Ts5, lost chloramphenicol resistance but retained MLS resistance, indicative of Tn917 transposition into host DNA . Analysis of DNA from MLSrCms isolates from both strains revealed Tn917 insertions into resident plasmids . Restriction analysis of plasmid DNA from four MLSrCms isolates from NC7Ts5 indicated four different insertion sites.

Plasmid, 1989 Nov, 22(3), 185 - 92
Structural organization of pLP1, a cryptic plasmid from Lactobacillus plantarum CCM 1904; Bouia A et al.; To construct shuttle vectors based on an endogenous replicon, we isolated a small cryptic plasmid (pLP1) from Lactobacillus plantarum CCM 1904 . The nucleotide sequence (2093 bp, 38.25 GC mol%) revealed one major open reading frame encoding for a 317 amino acid protein (Rep) . Comparisons with proteins encoded by other Gram-positive bacteria plasmids strongly suggest that the protein encoded by pLP1 has a replicative role . The presence of a consensus sequence including a tyrosine residue known to be the replication protein binding site to the DNA (in phage phi X174) strengthens this hypothesis . The DNA sequence contains also a sequence similar to the pC194 origin nick sequence, which initiates the plasmid replication at the plus origin, characteristic of plasmids which replicate following a rolling circle mechanism via single-stranded DNA intermediates . A set of 13 direct repeats of 17 bp could be involved in the expression of the incompatibility or in the copy number control as in the other plasmids . A promoter sequence located at the rep 5' region has been identified and is functional in Bacillus subtilis.

J Dairy Sci, 1989 Nov, 72(11), 2885 - 99
Lactobacillus effects on cholesterol: in vitro and in vivo results; Lin SY et al.; A double blind investigation was conducted on the influence of a commercially available tablet containing Lactobacillus acidophilus and Lactobacillus bulgaricus (Lactinex Becton Dickinson Microbiology Systems, Cockeysville, MD) on human serum lipoprotein concentrations . Tablets containing about 2 X 10(6) viable bacteria of Lactobacillus mixtures or placebo tablets were ingested by 354 nonfasting informed subjects in a dose of one tablet each, taken four times a day . There was a 3-wk washout period between two 6-wk treatment periods . The number of viable lactobacillus in unused returned tablets was the same at the end of the study as in the beginning . Analysis of paired data using Wilcoxon signed ranks test showed no major effects on lipoprotein concentrations for either the placebo-treated group or the lactobacilli-treated group . There were no statistically significant differences for low density lipoprotein concentrations between the lactobacilli-treated group and the placebo-treated group . The high density lipoprotein concentrations increased 1.8 to 3.0 mg/dl in both groups for both study periods . For total cholesterol the placebo-treated group experienced a statistically significant increase in the first period according to the Wilcoxon signed ranks test (from 208.0 to 215.0 mg/dl, P less than .001) but not according to a two-sample Student t test . Total cholesterol did not change significantly for the Lactobacillus-treated group in either period . Cardiac risk factor (ratio of total cholesterol to high density cholesterol) did not vary during the study . Lipoprotein values increased immediately following vigorous exercise compared with following 15 min of resting without either placebo or treatment . Sample controls for assay and reassay gave virtually identical values (coefficient of variation 1.6%), confirming that assay results were quite reliable . Thus, ingestion of commercially available Lactobacillus tablets, which contain about 2 X 10(6) cfu/tablet of L . acidophilus and L . bulgaricus cells in a dose of four tablets daily did not affect serum lipoprotein concentrations.

J Prosthet Dent, 1989 Nov, 62(5), 601 - 5
An in vitro study of the antibacterial and antifungal properties of an irreversible hydrocolloid impression material impregnated with disinfectant; Tobias RS et al.; The difficulties associated with the disinfection of alginate (irreversible hydrocolloid) materials have resulted in the development of an irreversible hydrocolloid impression material impregnated with an antimicrobial compound, didecyldimethyl ammonium chloride . This investigation assessed the antibacterial and antifungal properties in vitro of this innovative irreversible hydrocolloid material by using the agar well technique . The microorganisms used were Pseudomonas aeruginosa, Streptococcus mutans, Streptococcus sanguis, Lactobacillus odontolyticus rodriguez, Actinomyces odontolyticus, mixed salivary organisms, and Candida albicans . The results showed an absence of activity against Pseudomonas aeruginosa . Varying degrees of antibacterial activity were exhibited against the other microorganisms . It is concluded that it is not know whether the limited antibacterial and antifungal effect demonstrated in this study is sufficient to prevent bacterial and fungal colonization of the impression surface in the mouth during clinical practice.

Cancer, 1989 Nov 1, 64(9), 1769 - 76
Phase II randomized clinical trial of LC9018 concurrently used with radiation in the treatment of carcinoma of the uterine cervix . Its effect on tumor reduction and histology; Okawa T et al.; The clinical efficacy of LC9018, a biological response modifier prepared from heat-killed Lactobacillus casei YTT9018, used in combination with radiation was studied in a randomized controlled trial on 61 patients with carcinoma of the uterine cervix of Stage IIB or III . The combination therapy with LC9018 demonstrated a significant effect on tumor reduction, compared with radiation therapy alone, at the cumulative doses of 15-Gy and 30-Gy external irradiation (P less than 0.05) . Histologic study confirmed that LC9018 also enhanced the therapeutic effect of the irradiation . Moreover, LC9018 seemed to be useful in protecting the patients from leukopenia during radiotherapy . This study suggests that LC9018, when used in combination with radiotherapy, will be an effective adjuvant immunotherapeutic agent . More studies in a large series of patients will, however, be needed to establish its long-term efficacy, safety, and effects on both prognosis and enhancing radiotherapy.

Protein Eng, 1989 Oct, 3(1), 43 - 8
Site-directed alteration of Glu197 and Glu66 in a pyruvoyl-dependent histidine decarboxylase; McElroy HE et al.; Site-directed mutagenesis has been used to explore the role of two carboxylates in the active site of histidine decarboxylase from Lactobacillus 30a . The most striking observation is that conversion of Glu197 to either Gln or Asp causes a major decrease in catalytic rate while enhancing substrate binding . This is consistent with models based on X-ray diffraction results which suggest that the acid may protonate a reaction intermediate during catalysis . The Asp197 protein undergoes a suicide reaction with substrate, apparently triggered by inappropriate protonation of the intermediate . This leads to decarboxylation-dependent transamination which converts the pyruvoyl cofactor to an alanine, inactivating the enzyme . Conversion of Glu66 to Gln affects parameters of kinetic cooperativity . The mutation fixes the Hill number at approximately 1.5, midway between the pH-dependent values of the wild-type enzyme.

Oral Surg Oral Med Oral Pathol, 1989 Oct, 68(4), 401 - 5
Chlorhexidine rinse in prevention of dental caries in patients following radiation therapy; Epstein JB et al.; Patients who receive cancer radiotherapy, which compromises salivary gland function, may develop xerostomia . These patients are at increased risk to develop rampant dental caries . Streptococcus mutans and species of lactobacillus have been associated with dental caries . Quantitative counts of these organisms demonstrated high caries risk in 85% of patients studied . The use of chlorhexidine rinse to reduce the counts of S . mutans and lactobacillus was studied . A modest reduction in S . mutans was seen, but little effect was demonstrated on lactobacillus counts . Caries activity was shown to be related to lactobacillus count.

Community Dent Oral Epidemiol, 1989 Oct, 17(5), 240 - 4
Correlation between child caries incidence and S . mutans/lactobacilli in saliva after correction for confounding factors; Sullivan A et al.; The correlation between caries incidence and Streptococcus mutans/lactobacilli in saliva was studied in two different age groups, followed from ages 5 to 7 and from 12 to 14 . The coefficients of correlation were computed before and after correction for the confounding effect of oral hygiene and the alternative bacteria . The best value for S . mutans was found for the total material in the younger age group (r = 0.24) . For lactobacilli the best value was found for the total materials and in the subgroup with less favorable oral hygiene and S . mutans count in the older age group (r = 0.18) . The connection between caries incidence and these bacteria was shown to be weak at the individual level, particularly after correction for confounding . The caries differences at group level between subgroups with less favorable and favorable counts of the bacteria were also checked after correction for confounders . The "reduction" figures for S . mutans varied between 23 and 63% and for lactobacilli between 8 and 37% in the two sets of material.

Scand J Dent Res, 1989 Oct, 97(5), 408 - 14
Effect of a slow release transcutaneous scopolamine application on salivary flow, pH, buffering action, and salivary levels of Streptococcus mutans and lactobacilli; Arneberg P et al.; A motion sickness plaster releasing a powerful antisialogogic agent, scopolamine, was tested in a double blind clinical trial for its effect on salivary parameters in 14 healthy young men . The agent caused a decline in salivary flow rates, which was most pronounced during unstimulated conditions . Salivary pH and buffer capacity were also reduced . Salivary levels of Streptococcus mutans and lactobacilli showed a tendency to increase during 2 days on the antisialogogic agent, but the effect on S . mutans levels was not statistically significant.

Indian J Biochem Biophys, 1989 Oct, 26(5), 329 - 33
Glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase from Lactobacillus casei: responses with different modulators; Menezes L et al.; Glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) were separated and partially purified from glucose-grown cells of Lactobacillus casei . The enzymes had similar pH optima, thermosensitivity and molecular weights . They had different net charges and their pI values were 5.38 and 4.52, respectively . Histidine, arginine, lysine and cysteine residues were essential for the activity of G6PD, and all the above amino acids with the exception of lysine were required for 6PGD activity . Mg2+ activated 6PGD up to 15 mM concentration, above which it was inhibitory . It had no effect on G6PD activity . G6PD was specific for NADP+, but 6PGD showed some activity with NAD+ as the cofactor, although it was essentially NADP(+)-preferring . Both the enzymes, were inhibited by NADPH . 6PGD was also inhibited by its product, ribulose 5-phosphate . ATP inhibited 6PGD only at subsaturating concentrations of NADP+ . The inhibition was sigmoidal in the absence of Mg2+ and hyperbolic in its presence.

Appl Environ Microbiol, 1989 Oct, 55(10), 2579 - 82
Characterization of a Lactobacillus strain producing white crystals on cheddar cheese; Rengpipat S et al.; From an enrichment culture of white-crystal deposits from aged Cheddar cheese, an atypical Lactobacillus strain was characterized . The new isolate is facultatively heterofermentative, has a G + C content of 40 mol%, and produces D and L isomers of lactic acid . The strain had a limited ability to ferment carbohydrates . It utilized fructose, galactose, glucose, lactose, maltose, mannose, and ribose but was negative for esculin, gluconate, citrate, and several other carbon sources . The isolate also had low DNA-DNA homologies with strains of Lactobacillus casei and Lactobacillus plantarum . Cheese prepared with milk containing the isolate developed white crystals during curing . Formation of copious D-lactate from unknown substrates during curing probably caused the white-crystal deposits . The strain has been deposited in the American Type Culture Collection (ATCC 49178).

J Dairy Sci, 1989 Oct, 72(10), 2483 - 94
Acidophilus milk products: a review of potential benefits to consumers; Gilliland SE; During the past 80 yr considerable attention has been sporadically directed on benefits derived from consumption of milk products containing Lactobacillus acidophilus . Most earlier work dealt with the use of fermented acidophilus milk to treat intestinal infections . More recent studies have focused on other aspects of health or nutritional benefits that might be derived from this organism . These studies have shown that consumption of milk products containing L . acidophilus has the potential for: 1) preventing or controlling intestinal infections, 2) improving lactose digestion in persons classified as lactose maldigestors, 3) helping control serum cholesterol levels, and 4) exerting anticarcinogenic activity . Based on newer knowledge of L . acidophilus, a single strain of the organism probably will not produce all these benefits at optimal levels . Careful selection of specific strains of L . acidophilus combined with proper production and handling procedures will be necessary to ensure that desired benefits are provided to consumers.

Ann R Australas Coll Dent Surg, 1989 Oct, 10, 62 - 71
Advances in oral microbiology; Theilade E; More than 200 species of micro-organisms have been identified in the resident oral microflora colonizing teeth and oral mucosa . Their numbers and proportions are regulated by several ecological mechanisms such as antimicrobial factors in saliva and gingival fluid, intermicrobial synergism and antagonism, host diet, etc . Due to their pathogenic potential, oral micro-organisms cause dental caries, periodontal disease, mixed anaerobic infections of oral tissues, and sometimes infections in other organs . The role of specific bacteria or virulence factors in plaque-induced diseases is difficult to assess because of the microbial complexity and variability of dental plaque . Correlations have been established between Streptococcus mutans, lactobacilli and dental caries, and also between spirochaetes, certain Gram-negative rods and periodontal inflammation . The predictive value of microbiological tests as indicators of active caries or periodontal destruction is, however, too low to justify clinical use . Preventive methods such as plaque control and sugar restriction help establish a microflora compatible with oral health.

Biochem Pharmacol, 1989 Sep 15, 38(18), 2985 - 93
Deoxyuridylate effects on thymidylate synthase-5-fluorodeoxyuridylate-folate ternary complex formation; Spears CP et al.; The competitive basis and specificity of deoxyuridylate (dUMP)-mediated decreases in thymidylate synthase-5'-fluorodeoxyuridylate-folate (TS-FdUMP-folate) ternary complex formation at low concentrations of folates were investigated using charcoal isolation of protein-bound {3H}FuUMP ligand . Reaction conditions used 0.02 microM TS (Lactobacillus casei) and 0.10 microM {3H}FdUMP incubated for 10 min at 37 degrees and pH 7.4 . Decreases in counts below control (C) values in dUMP-added samples (S) were expressed as C/S ratios . At CH2--H4PteGlu1 or H4PteGlu1 concentrations below 10 microM, highly linear relationships were found to exist between C/S value and dUMP concentrations, expressed as dUMP/FdUMP ratios . For H4PteGlu1, maximal C/S values for dUMP interference occurred at the lowest H4PteGlu1 concentrations, approaching the value of the TS-FdUMP binary complex . The efficiency of ternary complex formation by H4PteGlu1 was 28 +/- 5% of CH2--H4PteGlu1 values at concentrations below 1.0 microM . The protective effect of increasing H4PteGlu1 against dUMP interference resulted in a linear relationship between the logarithm of H4PteGlu1 concentration and the slope of dUMP interference (C/S vs dUMP/FdUMP) . In contrast, the results with CH2--H4PteGlu1 were biphasic . At concentrations of CH2--H4PteGlu1 lower than 0.5 microM, C/S values were greater than those for binary complex alone, a result related to CH2--H4PteGlu1 consumption based on {5-3H}dUMP tritium-release studies . At concentrations of CH2--H4PteGlu1 above 1.0 microM, however, dUMP interference was nearly abolished . Kinetic analysis of the data suggests that this effect of the 5,10-methylene moiety may result in part from positive allosteric effects of first site TS-FdUMP-CH2--H4PteGlu1 ternary complex binding on acceleration of second site binding, in addition to slowed rates of dissociation . Other folylmonoglutamates showed relatively poor TS-{3H}FdUMP-folate complex formation: at 500 microM folate, as a percentage of CH2--H4PteGlu1 values, these were 29.6% for dihydrofolate, 7.5% for 5-CH3--H4PteGlu1, 3.0% for CH = H4PteGlu1, 1.6% for folic acid, 1.1% for 5-CHO--H4PteGlu1 (leucovorin) and 0.9% for 10-CHO--H4PteGlu1 . Inhibitory effects by dUMP were consistent with binary complex effects alone for these folates . Study of methotrexate, as the monoglutamate and the hexaglutamate, suggested that ternary complexes with dUMP are favored over those with FdUMP at high concentrations of the antifolate . Our results indicate that activation of leucovorin to over 0.5 microM in intracellular CH2--H4PteGlu1 equivalents may be a requirement for achieving complete TS inhibition by FdUMP in the presence of excess conce

Br J Urol, 1989 Sep, 64(3), 270 - 4
Microbiology of the urethral (frequency and dysuria) syndrome . A controlled study with 5-year review; Gillespie WA et al.; In a clinical and microbiological study of women with urinary frequency and dysuria (excluding those with bacterial cystitis), 41 patients were compared with 42 control subjects . No difference was found between patients and controls in the incidence of infection by Chlamydia trachomatis or other sexually transmitted organisms . The numbers of lactobacilli and other fastidious organisms in the urine of patients with either mild or severe symptoms were similar and did not differ from the numbers in the urine of control subjects . The numbers of leucocytes in urine were also similar in both patients and controls . Our findings support the view that the urethral syndrome is not caused by bacterial or chlamydial infection.

Clin Lab Med, 1989 Sep, 9(3), 525 - 33
Vaginitis/vaginosis; Spiegel CA; Vaginitis/vaginosis is an extremely common medical problem . Most cases are caused by yeast (predominantly Candida albicans), the protozoan Trichomonas vaginalis, or a specific mixture of bacteria (bacterial vaginosis) . The prevalence of each of these varies with the patient population . The clinical signs used in differentiating among these and the associated bacterial flora are shown in Table 3 . Because vaginitis/vaginosis cannot be adequately diagnosed solely on the basis of symptoms or physical examination, some laboratory methods are required . Yeast vaginitis is diagnosed by microscopic detection of budding yeast or pseudohyphae in vaginal secretions . The most sensitive method for detection of Trichomonas vaginalis is culture, but microscopic methods are more commonly used . Wet-mount examination for motile trichomonads is the least sensitive microscopic method . The sensitivity is increased when fluorescent monoclonal antibodies are used . Bacterial vaginosis may be diagnosed in the clinic by detecting three or more of the following on examination: (1) homogeneous adherent discharge, (2) vaginal fluid pH greater than 4.5, (3) amine odor, and (4) clue cells . A diagnosis may also be made by detecting the replacement of lactobacilli by a mixed presumably anaerobic flora . This is accomplished by examining a Gram stain of vaginal fluid . It is not uncommon for a woman to have more than one microbial source for her vaginal signs and symptoms . A vaginal examination should include appropriate tests for detection of all three of these agents.

Arch Intern Med, 1989 Sep, 149(9), 1932 - 6
Association between bacterial vaginosis and acute cystitis in women using diaphragms; Hooton TM et al.; We hypothesized that the increased vaginal fluid pH and altered vaginal microflora characteristic of bacterial vaginosis might predispose young women to introital colonization with Escherichia coli and to acute cystitis . To evaluate this hypothesis, we studied 291 women who presented with acute urinary symptoms for association of clinically defined bacterial vaginosis and vaginal conditions associated with this syndrome (increased vaginal fluid pH, absence of lactobacilli, and abnormal vaginal fluid gas-liquid chromatographic patterns) with E coli introital colonization and urinary tract infection . Escherichia coli introital colonization and urinary tract infection were both significantly more frequent among women with a high vaginal fluid pH, an absence of vaginal lactobacilli, or an abnormal vaginal fluid gas-liquid chromatographic pattern characteristic of bacterial vaginosis . Escherichia coli introital colonization was also more frequent in women with bacterial vaginosis . These associations and an association of bacterial vaginosis and E coli urinary tract infection were strong only among the 144 women who were diaphragm users . We conclude that bacterial vaginosis, or an altered vaginal microflora as reflected by an abnormal gas-liquid chromatographic pattern characteristic of bacterial vaginosis, is associated with E coli introital colonization and acute symptomatic urinary tract infection in women who use diaphragms.

Oral Microbiol Immunol, 1989 Sep, 4(3), 165 - 8
Mutans streptococci and lactobacilli in saliva from children with insulin-dependent diabetes mellitus; Twetman S et al.; The quantitative distribution of mutans streptococci and lactobacilli in saliva of insulin-dependent diabetic children was compared with a group of healthy children and related to the metabolic control of the disease . The study group, consisting of 94 boys and girls (age 4-19) with type 1 diabetes was matched by sex and age with a non-diabetic control group . Stimulated whole saliva was collected and flow rate, buffer capacity and the levels of mutans streptococci and lactobacilli were analysed in all children . In the diabetic group, total salivary proteins and glucose content of saliva were determined . Data on caries experience were recorded from the dental cards of all children . There were no difference in the distribution or number of mutans streptococci between the groups, but significantly (p less than 0.05) lower levels of lactobacilli were found among the diabetic children . The number of lactobacilli was positively correlated (p less than 0.05) to glucose concentration in saliva . There was no difference in the prevalence of caries between the groups . The present findings suggest that the dietary treatment of young insulin dependent diabetics gives rise to a reduced number of lactobacilli in saliva but does not affect the mutans streptococci.

Microbiologia, 1989 Sep, 5(2), 105 - 12
Selected characteristics of several strains of Lactobacillus plantarum; Mayo B et al.; Several relevant characteristics have been studied in nine Lactobacillus plantarum strains isolated from Cabrales cheese . They fermented lactose efficiently and possessed both beta-galactosidase and beta-phosphogalactosidase activities, but no significant proteolytic activity was detected . Antimicrobial susceptibility tests revealed no high level resistance to any of the fourteen compounds tested . All the strains had a high content of extrachromosomal DNA of unknown function . A recombinant plasmid comprising pUC19 from Escherichia coli and a small cryptic plasmid from L . plantarum has been constructed and may be used to develop a shuttle vector for these species.

Plasmid, 1989 Sep, 22(2), 175 - 9
The complete nucleotide sequence of a small cryptic plasmid from Lactobacillus plantarum; Skaugen M; The complete nucleotide sequence of a cryptic plasmid isolated from a Lactobacillus plantarum strain has been determined . The plasmid, designated pC30i1, has a molecular size of 2140 bp and a GC content of 37% . The sequence contains one major open reading frame (ORF R) of 951 bp, encoding a basic polypeptide of 317 amino acids, and a molecular weight of 36,956 . ORF R shows extensive sequence similarity with genes coding for replication-associated proteins in a group of gram-positive plasmids known to replicate via single-stranded intermediates (ssDNA plasmids), and a stretch of 9 amino acids in the translation of ORF R closely matches a conserved region in these proteins, as well as the active site of the phi X174 Rep protein . Sequences similar to the ssDNA plasmid origins of replication are also present in the pC30i1 sequence, strengthening the hypothesis that pC30i1 belongs to the ssDNA plasmid family . The other main feature of the pC30i1 sequence is a noncoding region consisting of 14 direct, imperfect repeats of a 17-bp sequence, which may have an incompatibility function.

Antibiot Khimioter, 1989 Sep, 34(9), 716 - 8
{Resistance to antibiotics of Lactobacillus isolated from the intestines of healthy persons}; Tiurin MV; Lactobacilli constitute a significant part of the microbial population in the gastrointestinal tract of humans and animals . Sensitivity of intestinal lactobacilli to 11 chemotherapeutic drugs was tested with the method of serial dilutions in the solid medium MRS under aerobic and anaerobic conditions . Criteria for dividing the organisms into sensitive and resistant ones with respect to the drugs are proposed . Prevalence of lactobacilli polyresistant strains in the intestine contents of healthy persons at the age of 25 to 50 years being in prolonged constant contact with antibiotics was shown . On the whole 77 various combinations of the antibiotic resistance markers were detected in 141 tested strains . The most frequent were isolated simultaneously resistant to 6 or 7 antibiotics . Different levels of the antibiotic resistance in the strains tested under the aerobic and anaerobic conditions were observed.

Zh Mikrobiol Epidemiol Immunobiol, 1989 Sep, (9), 3 - 6
{The effect of enterococci on normalizing the intestinal microflora in experimental dysbacteriosis}; Korshunov VM et al.; The normal microflora of the intestine produces essential influence on the vital activity of the host . The exposure of the body to the action of different unfavorable factors (roentgen radiation, the administration of antibiotics, Salmonella infection, etc) results in changes in the normal microflora of the gastrointestinal tract . This work was aimed at the study of the influence of Streptococcus faecium YDC-48 on the intestinal microflora of mice in experimental (chemotherapeutic, postirradiation) dysbacteriosis and Salmonella infection . The effect of the oral administration of S . faecium YDC-48 on the correction of the intestinal microflora of mice in cases of dysbacteriosis etiology was studied . The intragastric administration of S . faecium YDC-48 was found to induce an increase in the level of lactobacterin and a decrease in the number of opportunistic microorganisms in chemotherapeutic and postirradiation dysbacteriosis . The oral administration of S . faecium YDC-48 decreased the manifestations of intestinal dysbacteriosis in experimental Salmonella infection . The possibility of developing a preparation on the basis of S . faecium YDC-48, a representative of normal intestinal microflora, is discussed.

J Pharm Sci, 1989 Sep, 78(9), 749 - 52
Competitive protein binding assay for piritrexim; Woolley JL Jr et al.; A competitive protein binding assay for piritrexim (PTX, 1) that makes use of a commercially available radioassay kit for methotrexate has been developed . After it is selectively extracted from plasma, PTX competes with {125l}methotrexate for binding to dihydrofolate reductase isolated from Lactobacillus casei . Free drug is separated from bound drug by adsorption to dextran-coated charcoal . Piritrexim is measurable over a range of 0.01 to 10.0 micrograms/mL in plasma with a coefficient of variation less than 15% . The limit of sensitivity of the assay is approximately 2 ng/mL . An excellent correlation between this assay and a previously published HPLC method was found . published HPLC method was found.

Reg Immunol, 1989 Sep-Oct, 2(5), 285 - 93
Phenotypic and functional analysis of oral mucosal macrophages; Barbeau J et al.; Oral mucosal macrophages were prepared in single cell suspensions from the oral mucosa of BALB/c mice and isolated by adherence to glass . Adherent cells were identified on the basis of morphological, cytochemical, phenotypical, and functional characteristics and compared with peritoneal adherent cells . Adherent cells were found to be esterase positive and could perform non immune phagocytosis . From immunofluorescence studies it was found that about 30% of oral adherent cells bear macrophage differentiation (Mac 1) and Ia antigens, whereas the F4/80 marker could not be detected . The presence of Ig receptors was assessed by the binding of IgA and IgG-coated fluorescent microspheres; distinct populations of mucosal macrophages were shown to display IgA and IgG receptors (25% each) with a significant percentage of double-bearers (15%) . The effector functions of these Ig receptors was verified by opsono-phagocytosis of live lactobacilli . Murine oral mucosal tissue appears to host a heterogeneous population of resident macrophages including IgA-dependent phagocytic cells which would be particularly well suited for immune defense functions at secretory sites.

Zh Mikrobiol Epidemiol Immunobiol, 1989 Sep, (9), 11 - 4
{An analysis of a process for culturing Lactobacillus acidophilus using a method of spectroturbidimetry}; Bezrukova AG et al.; Changes in the spectrum of the opacity of biodispersions containing L . acidophilus at the stage of growth have been studied . The pronounced positive correlation between the opacity of dispersion and the titer of cells, determined by the method of ultimate dilutions, have been shown.

Appl Environ Microbiol, 1989 Sep, 55(9), 2206 - 13
Characterization of the temperate bacteriophage phi adh and plasmid transduction in Lactobacillus acidophilus ADH; Raya RR et al.; Lactobacillus acidophilus ADH is lysogenic and harbors an inducible prophage, phi adh . Bacteriophage were detected in cell lysates induced by treatment with mitomycin C or UV light . Electron microscopy of lysates revealed phage particles with a hexagonal head (62 nm) and a long, noncontractile, flexible tail (398 nm) ending in at last five short fibers . Phage phi adh was classified within Bradley's B1 phage group and the Siphoviridae family . The phi adh genome is a linear double-stranded DNA molecule of 41.7 kilobase pairs with cohesive ends: a physical map of the phi adh genome was constructed . A prophage-cured derivative of strain ADH, designated NCK102, was isolated from cells that survived UV exposure . NCK102 did not exhibit mitomycin C-induced lysis, but broth cultures lysed upon addition of phage . Phage phi adh produced clear plaques on NCK102 in media containing 10 mM CaCl2 at pH values between 5.2 and 5.5 . A relysogenized derivative (NCK103) of NCK102 was isolated that exhibited mitomycin C-induced lysis and superinfection immunity to phage phi adh . Hybridization experiments showed that the phi adh genome was present in the ADH and NCK103 chromosomes, but absent in NCK102 . These results demonstrated classic lytic and lysogenic cycles of replication for the temperate phage phi adh induced from L . acidophilus ADH . Phage phi adh also mediates transduction of plasmid DNA . Transductants of strain ADH containing pC194, pGK12, pGB354, and pVA797 were detected at frequencies in the range of 3.6 x 10(-8) to 8.3 x 10(-10) per PFU . Rearrangements or deletions were not detected in these plasmids as a consequence of transduction . This is the first description of plasmid transduction in the genus Lactobacillus.

Clin Chim Acta, 1989 Aug 15, 183(2), 171 - 82
A convenient enzymatic method for the determination of 4-methyl-2-oxopentanoate in plasma: comparison with high performance liquid chromatographic analysis; Schadewaldt P et al.; A simple and rapid spectrophotometric method for the estimation of 4-methyl-2-oxopentanoate in plasma samples by use of NAD+-dependent D-2-hydroxyisocaproate dehydrogenase from Lactobacillus casei ssp . pseudoplantarum is described . It is based on the kinetic measurement of the decrease of NADH absorbance at 334 nm . Applicability is demonstrated by comparative measurement of 4-methyl-2-oxopentanoate content in plasma of patients with maple syrup urine disease by the enzymatic and a reversed phase high performance liquid chromatographic method.

Br Dent J, 1989 Aug 5, 167(3), 99 - 102
Identification of caries risk in schoolchildren: salivary buffering capacity and bacterial counts, sugar intake and caries experience as predictors of 2-year and 3-year caries increment; Wilson RF et al.; Six variables which are capable of measurement at the chairside were assessed for their ability to identify children who would experience high caries increments during the subsequent 2 or 3-year period . The predictor variables measured in 84 urban schoolchildren, aged 11-12 years at baseline, were: baseline caries experience, salivary buffering power, counts of salivary Streptococcus mutans and lactobacilli, and two estimates of between-meal sugar intake . All the predictor variables showed statistically significant correlations with either 2-year or 3-year caries increment . Approximately 25% of subjects were identified as high risk individuals on the basis of a 2-year DFS increment of 5 and above, or a 3-year increment of 8 and above . None of the predictor variables achieved the target predictive value of 80%, either individually or in combination . The combination of Streptococcus mutans counts and buffering capacity measurements at baseline correctly identified low risk during the 3-year period in 78% of individuals (specificity), but only identified 12 out of 19 individuals (63%) at high risk (sensitivity), giving a predictive value of 75% . The predictive value for baseline caries experience was 66% . The results of the present study indicate that the salivary diagnostic tests have potential, but need further development before they can be used with confidence in clinical practice.

Protein Eng, 1989 Aug, 2(8), 627 - 31
Dihydrofolate reductase: control of the mode of substrate binding by aspartate 26; Jimenez MA et al.; The complex of Lactobacillus casei dihydrofolate reductase with the substrate folate and the coenzyme NADP+ has been shown to exist in solution as a mixture of three slowly interconverting conformations whose proportions are pH-dependent and which differ in the orientation of the pteridine ring of the substrate in the binding site . The Asp26----Asn mutant of L . casei dihydrofolate reductase has been prepared by oligonucleotide-directed mutagenesis and studied by one- and two-dimensional 1H-NMR spectroscopy . NMR studies of the mutant enzyme--folate--NADP+ complex show that this exists to greater than 90% in a single conformation over the pH* range 5-7.1 . The single conformation observed corresponds to conformation I (the 'methotrexate-like' conformation) of the wild-type enzyme--folate--NADP+ complex . These observations demonstrate that Asp26 is the ionizable group controlling the pH-dependence of the conformational equilibrium seen in the wild-type enzyme.

Appl Environ Microbiol, 1989 Aug, 55(8), 1901 - 6
Antibacterial activity of Lactobacillus sake isolated from meat; Schillinger U et al.; A total of 221 strains of Lactobacillus isolated from meat and meat products were screened for antagonistic activities under conditions that eliminated the effects of organic acids and hydrogen peroxide . Nineteen strains of Lactobacillus sake, three strains of Lactobacillus plantarum, and one strain of Lactobacillus curvatus were shown to inhibit the growth of some other lactobacilli in an agar spot test; and cell-free supernatants from 6 of the 19 strains of L . sake exhibited inhibitory activity against indicator organisms . Comparison of the antimicrobial spectra of the supernatants suggested that the inhibitory compounds were not identical . One of the six strains, L . sake Lb 706, was chosen for further study . The compound excreted by L . sake Lb 706 was active against various lactic acid bacteria and Listeria monocytogenes . Its proteinaceous nature, narrow inhibitory spectrum, and bactericidal mode of action indicated that this substance is a bacteriocin, which we designated sakacin A . Curing experiments with two bacteriocin-producing strains of L . sake resulted in mutants that lacked both bacteriocin activity and immunity to the bacteriocin . Plasmid profile analysis of L . sake Lb 706 and two bacteriocin-negative variants of this strain indicated that a plasmid of about 18 megadaltons may be involved in the formation of bacteriocin and immunity to this antibacterial compound . In mixed culture, the bacteriocin-sensitive organisms were killed after the bacteriocin-producing strain reached maximal cell density, whereas there was no decrease in cell number in the presence of the bacteriocin-negative variant.

Am J Clin Nutr, 1989 Aug, 50(2), 359 - 63
Aging: effect on hepatic metabolism and transport of folate in the rat; Horne DW et al.; Effects of aging on hepatic folate metabolism and transport were assessed in male Fisher 344 rats . Total serum and hepatic folate levels were measured . Hepatic folates were measured by high-performance liquid chromatography and by Lactobacillus casei assay . Transport of 5-methyltetrahydrofolate (5-CH3-H4PteGlu) was measured in isolated hepatocytes . Serum folate declined with aging; however, neither the total folate level nor the distribution of hepatic folate coenzymes was affected by the aging process . The level of liver folate monoglutamates was not significantly different in any group . The initial rate of uptake of 5-CH3-H4PteGlu was significantly decreased in hepatocytes from the 24-mo-old rats, as was the ability to concentrate this folate from the medium . Aged rats maintain apparently normal levels of hepatic folates despite decreased serum levels and decreased ability to take up folates, suggesting that membrane transport of folates may not be a limiting factor in hepatic folate assimilation.

J Reprod Med, 1989 Aug, 34(8 Suppl), 581 - 6; discussion 586-7
Advances in the understanding of bacterial vaginosis; Thomason JL et al.; Bacterial vaginosis is a disease that results from massive overgrowth of vaginal bacterial flora . The exact etiology is unknown . The major components of the normal bacterial flora, peroxide-producing lactobacilli, are replaced by non-peroxide-producing lactobacilli, allowing overgrowth of anaerobic and gram-negative aerobic flora . Anaerobic bacteria produce enzymes, aminopeptidases, that degrade protein and decarboxylases that convert amino acids and other compounds to amines . Those amines contribute to the signs and symptoms associated with the syndrome, raising the vaginal pH and producing a discharge odor . The excessive amounts of bacteria characteristic of the syndrome attach to epithelial cell surfaces, resulting in "clue" cells . Nearly half the patients report no noticeable symptoms, but many develop a characteristic copious, malodorous discharge within six months if untreated . Serious infectious sequelae are associated with bacterial vaginosis, including salpingitis, abscesses, endometritis and pelvic inflammatory disease . There is also a danger to pregnant women because of premature rupture of the membranes and premature labor . Clindamycin and metronidazole are considered effective therapy for the disease . Treatment of sexual partners remains controversial since sexual transmission has not been proven unequivocally.

Infect Immun, 1989 Aug, 57(8), 2447 - 51
Elimination of vaginal colonization with Escherichia coli by administration of indigenous flora; Herthelius M et al.; A persistent vaginal colonization with a pyelonephritogenic strain of Escherichia coli, induced by administration of amoxicillin, was established in four adult cynomolgus monkeys . This colonization mimicked the one seen in urinary tract infection-prone human females . Attempts to eliminate the E . coli colonization and restore normal conditions were made . Either suspensions of lactobacilli or vaginal fluid from a healthy unmanipulated monkey was administered as repeated vaginal flushes for 5 to 9 days . A total elimination of vaginal E . coli was observed in two of six experiments with lactobacilli, and a decrease was observed in the other four . A better result was obtained with flushes of vaginal fluid, which eliminated the E . coli colonization in eight of eight experiments . In two of these, a single flush was sufficient to obtain a decolonization . The ability of fresh vaginal fluid to eliminate E . coli from the vagina could be transferred from one monkey to another . This study demonstrates the role of the normal flora in the defense against genital colonization with potentially pathogenic adhering E . coli . The possible clinical relevance of these findings must be further examined.

Int J Food Microbiol, 1989 Aug, 9(1), 33 - 43
Characterization of lactic acid bacteria isolated from vacuum-packed cooked ring sausages; Korkeala H et al.; The bacterial populations of the surface layer and the centre of 15 spoiled vacuum-packed cooked ring sausages were characterized . About 95% of the total bacterial population in the surface layer and 55% at the centre were lactic acid bacteria . Another large bacterial group at the centre consisted of Bacillus spp . The lactic acid bacteria on the surface and at the centre were quite similar . Atypical streptobacteria, i.e . homofermentative psychrotrophic lactobacilli, were a major group of lactic acid bacteria in the surface layer of the spoiled sausages . Three main homofermentative groups could be observed on the basis of different carbohydrate patterns . Heterofermentative lactic acid bacteria belonged mainly to genus Leuconostoc . The proportion of leuconostocs in the spoiled sausages was also quite large . They could be divided into three main groups on the basis of different carbohydrate fermentation patterns . The lactic acid bacteria population of spoiled cooked ring sausages thus seemed to be heterogeneous . The strains isolated resembled strains observed by other workers in meat and meat products.

J Dent Res, 1989 Aug, 68(8), 1242 - 6
Associations between salivary levels of Streptococcus mutans, Streptococcus sobrinus, lactobacilli, and caries experience in Kenyan adolescents; Beighton D et al.; Salivary levels of mutans streptococci (S . mutans and S . sobrinus) and lactobacilli were determined in a random sample of rural Kenyans between 15 and 19 years of age (n = 149) . It is possible for the natural history of dental caries in this population to be studied since it is characterized by a limited access to conventional dental treatment . Using a short set of biochemical tests, we identified from seven to ten presumptive mutans streptococcus colonies--cultured from the saliva of each individual--to differentiate between S . mutans and S . sobrinus . No colonies resembling S . rattus (S . mutans serotype b) were isolated . Lactobacilli were identified as Gram-positive, catalase-negative rods . The mean D1-4MFS and D3-4MFS were 7.03 +/- 6.43 and 1.46 +/- 3.44, respectively . The mean mutans streptococcus and lactobacillus levels were 8.7 x 10(4) and 6.7 x 10(4), respectively . The salivary mutans streptococcus and lactobacillus levels were significantly correlated (p less than 0.01) . Of the subjects, 64% harbored only S . mutans, 4% only S . sobrinus, 30% both species, and 2% neither . Lactobacilli were ubiquitous . The caries experience of the group was significantly (p less than 0.001) correlated with both the total salivary level of mutans streptococci and the salivary S . mutans levels, but not with the salivary S . sobrinus level.

Antimicrob Agents Chemother, 1989 Aug, 33(8), 1383 - 4
In vitro activities of daptomycin and other antimicrobial agents against vancomycin-resistant gram-positive bacteria; de la Maza L et al.; A comparative evaluation of daptomycin and eight other antimicrobial agents was performed by the agar dilution technique with 56 strains of vancomycin-resistant gram-positive bacteria, including Leuconostoc, Lactobacillus, and Pediococcus spp . Erythromycin, deptomycin, clindamycin, and gentamicin exhibited the greatest activities, whereas penicillin, ampicillin, and cefotaxime showed moderate activities . The organisms were all highly resistant to vancomycin and cefoxitin.

Int J Food Microbiol, 1989 Aug, 9(1), 25 - 32
Antibiosis of some lactic acid bacteria including Lactobacillus acidophilus toward Listeria monocytogenes; Raccach M et al.; Eleven strains of lactic acid bacteria were tested by the 'spot' on the 'lawn' method for their antagonistic activity against four strains of Listeria monocytogenes . Four out of the five strains of lactic acid bacteria most antagonistic toward the pathogen were those cultures known to produce bacteriocins . Four other strains of lactic acid bacteria were not antagonistic against Listeria by this method . Seventeen inhibition zones of the pathogen were obtained at 25 degrees C as compared to 10 at 32 degrees C . Lactobacillus acidophilus strains NU-A and 88, growing in the presence of L . monocytogenes in milk prevented the latter from attaining populations it would have in pure culture (P less than 0.01) . 10(1.4)-10(3.5) lower numbers were noted . L . acidophilus in most cases exhibited a bacteriostatic effect toward the pathogen except for strain 88 which appeared to have a bactericidal effect (P less than 0.01) against Listeria strain OH . The lactobacilli reduced the pH of the milk to 4.7 over a 24 h period, showing that acid played a role in the observed antibiosis.

Scand J Dent Res, 1989 Aug, 97(4), 307 - 15
Presence of mutans streptococci and various types of lactobacilli in interdental spaces related to development of proximal carious lesions; Crossner CG et al.; During a 2-yr study period samples from saliva, the tongue, and 276 interdental spaces were obtained from 23 7-yr-old children in order to (a) relate the presence of lactobacilli in various oral sites to the occurrence of lactobacilli in saliva, and (b) relate the presence of mutans streptococci and various types of lactobacilli interdentally to the development of proximal carious lesions . The results showed an increased number of interdental samples containing lactobacilli with an increasing number of salivary lactobacilli . Furthermore, lactobacilli were never found interdentally without the presence of mutans streptocci, lactobacilli proved to be the more suitable microorganism for prediction of proximal carious lesions . Neither the number nor the differentiation into different species of interdental lactobacilli seemed to be of importance, but simply whether they were present . The presence of lactobacilli probably reflects a caries-inducing environment (etiologic microflora + fermentable carbohydrates), thus explaining their high predictive ability compared to their rather limited etiologic importance in the initiation of decay.

J Med Chem, 1989 Aug, 32(8), 1895 - 905
On the structure selectivity problem in drug design . A comparative study of benzylpyrimidine inhibition of vertebrate and bacterial dihydrofolate reductase via molecular graphics and quantitative structure-activity relationships; Selassie CD et al.; Quantitative structure-activity relationships (QSAR) have been derived for the action of 68 5-(substituted benzyl)-2,4-diaminopyrimidines on dihydrofolate reductase (DHFR) from Lactobacillus casei and chicken liver . The QSAR are analyzed with respect to the stereographics models of the active sites of the enzymes and found to be in good agreement . Using these QSAR equations, we have attempted to design new trimethoprim-type antifolates having higher selectivity for the bacterial enzyme . The general problem of developing selective inhibitors is discussed.

J Leukoc Biol, 1989 Aug, 46(2), 89 - 95
Increased production of cytotoxic macrophage progenitors by Lactobacillus casei in mice; Nanno M et al.; Heat-killed Lactobacillus casei YIT9018 (LC9018), when administered intravenously to normal mice, induced increase in Mac-1+ cells and Mac-2+ cells but not in Mac-3+ cells in spleen . The number of both populations changed in the same time course and was maximal 14 d after the administration . To know the effect of LC9018 on hematopoietic progenitor level, we examined the number of macrophage colony-forming cells (M-CFC), granulocyte-macrophage CFC (GM-CFC), and colony-forming units in spleen (CFU-S) in bone marrow 3 d after the administration . LC9018 stimulated the proliferation of M-CFC but not that of GM-CFC and CFU-S . LC9018-induced M-CFC were similar to normal M-CFC in dependence on macrophage colony-stimulating factor (M-CSF) and buoyant density . M-CFC-derived macrophages cultured in the presence of M-CSF expressed Mac-1 and Mac-2 but not Mac-3 . They showed cytotoxic activity against syngenic tumor cells, Meth A, via direct contact, when assayed by using an in vitro colony inhibition assay or an in vivo Winn test . These results indicate that LC9018 stimulates the proliferation of cytotoxic macrophage progenitors in bone marrow and induces their differentiation in spleen . These effects may be one of the ways in which LC9018 suppresses tumor growth.

FEMS Microbiol Lett, 1989 Jul 15, 51(1), 149 - 52
Conjugal transfer of plasmid pIP501 from Lactococcus lactis to Lactobacillus delbrückii subsp . bulgaricus and Lactobacillus helveticus; Langella P et al.; Plasmid pIP501 was transferred by conjugation from Lactococcus lactis to Lactobacillus delbruckii subsp . bulgaricus and Lactobacillus helveticus . Only Lb . delbruckii subsp . bulgaricus transconjugants could act as a donor in crosses with Lc . lactis . No Lactobacillus transconjugants were detected after inter- or intra-species Lactobacillus crosses . Plasmid pIP501 has undergone no detectable deletion or rearrangement during transfer from Lc . lactis to Lactobacillus strains.

Biochemistry, 1989 Jul 11, 28(14), 5743 - 50
A kinetic study of wild-type and mutant dihydrofolate reductases from Lactobacillus casei; Andrews J et al.; A kinetic scheme is presented for Lactobacillus casei dihydrofolate reductase that predicts steady-state kinetic parameters . This scheme was derived from measuring association and dissociation rate constants and pre-steady-state transients by using stopped-flow fluorescence and absorbance spectroscopy . Two major features of this kinetic scheme are the following: (i) product dissociation is the rate-limiting step for steady-state turnover at low pH and follows a specific, preferred pathway in which tetrahydrofolate (H4F) dissociation occurs after NADPH replaces NADP+ in the ternary complex; (ii) the rate constant for hydride transfer from NADPH to dihydrofolate (H2F) is rapid (khyd = 430 s-1), favorable (Keq = 290), and pH dependent (pKa = 6.0), reflecting ionization of a single group . Not only is this scheme identical in form with the Escherichia coli kinetic scheme {Fierke et al . (1987) Biochemistry 26, 4085} but moreover none of the rate constants vary by more than 40-fold despite there being less than 30% amino acid homology between the two enzymes . This similarity is consistent with their overall structural congruence . The role of Trp-21 of L . casei dihydrofolate reductase in binding and catalysis was probed by amino acid substitution . Trp-21, a strictly conserved residue near both the folate and coenzyme binding sites, was replaced by leucine . Two major effects of this substitution are on (i) the rate constant for hydride transfer which decreases 100-fold, becoming the rate-limiting step in steady-state turnover, and (ii) the affinities for NADPH and NADP+ which decrease by approximately 3.5 and approximately 0.5 kcal mol-1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibiot Khimioter, 1989 Jul, 34(7), 539 - 45
{Genetic nature of the antibiotic-resistance of Lactobacillus}; Tiurin MV et al.; One hundred and forty one strains of Lactobacillus were isolated from intestinal contents of persons being in long-term contact with antibiotics . Their sensitivity to 10 chemotherapeutic agents was studied with the method of serial dilutions in solid media under aerobic and anaerobic conditions . A single administration of antibiotics in the therapeutic doses led to selection of Lactobacillus polyresistant strains in the intestine of rats . The antibiotic resistance spectrum of the Lactobacillus cultures was unstable and changed under nonselective conditions of their storage and after their lyophilization or short-term exposure to heat . The changes in the resistance spectrum were accompanied by changes in the plasmid profile . An electrophoretogram of plasmid DNA from the intestinal isolate L plantarum MT205 is presented . Relation between the marker of lincomycin resistance and the presence of plasmid DNA weighing 130 kb was shown in the isolate.

Klin Med (Mosk), 1989 Jul, 67(7), 72 - 4
{The effect of the acidic milk mixture "Nariné" on intestinal microflora in patients with functional and inflammatory bowel diseases}; Ambartsumian KF et al.; A cultured milk mixture "Narine" (strain 317/402 lactobacilli and relevant metabolic products) given to 58 patients with various functional disorders and inflammation of the colon associated with dysbacteriosis resulted in a pronounced positive effect as related to intestinal microflora in 96.6% of the patients . In 75.8% of cases dysbacteriosis discontinued within 10 days.

J Wildl Dis, 1989 Jul, 25(3), 370 - 7
Fusobacterium necrophorum and Actinomyces pyogenes associated facial and mandibular abscesses in blue duiker; Roeder BL et al.; Anaerobic and aerobic cultures of facial and mandibular abscesses were made from 12 blue duiker (Cephalophus monticola fusicolor) housed at the Deer and Duiker Research Facility of the Pennsylvania State University (USA) . Increases in concentrations of total protein and serum globulin occurred in all cases . Actinomyces pyogenes was isolated from nine animals . Fusobacterium necrophorum was present in eight and Bacteroides sp . was found in seven animals; other genera of isolated bacteria included: Streptococcus (from two animals), Lactobacillus (one), Staphylococcus (one) and Actinomyces (two) . Eight (67%) of affected animals were less than or equal to 2 yr of age . Facial soft tissues and mandibles were the tissues most often affected . Tissues within the oral cavity were not affected at the time of presentation . A common finding, not reported in other host species with necrobacillosis, was the presence of nondestructive mandibular proliferation.

Br J Urol, 1989 Jul, 64(1), 39 - 44
Interstitial cystitis and the urethral syndrome: a possible answer; Wilkins EG et al.; A study was made of 20 patients fulfilling the criteria customarily used for the diagnosis of interstitial cystitis . A possible infective aetiology was sought by culture of bladder tissue, catheter and midstream specimens of urine, and urethral swabs by methods capable of detecting fastidious bacteria as well as aerobic pathogens . All bladder biopsies showed the histological appearances usually associated with interstitial cystitis, and bacteria were isolated from the catheter specimens and/or bladder biopsies of 12 patients . Eight of these isolates were fastidious bacteria, Gardnerella vaginalis (6) and Lactobacillus sp . (2) . Fastidious bacteria were isolated from the midstream specimen of urine (MSU) and/or urethral swab of 6 other patients . The correlation of the histological and bacteriological findings supports the hypothesis of an infective aetiology and suggests that the so-called urethral syndrome and interstitial cystitis may be the earlier and later stages of the same disease process . The importance of early diagnosis of infection in these patients is emphasised.

J Dent Res, 1989 Jul, 68(7), 1151 - 4
A microbiological study of early caries of approximal surfaces in schoolchildren; Marsh PD et al.; A cross-sectional epidemiological study has been undertaken to relate the bacterial composition of approximal dental plaque with the earliest stages of caries development in schoolchildren . Small samples of plaque were removed from multiple sites around the contact areas of 42 premolars extracted for orthodontic reasons from 29 schoolchildren (mean age = 13.5 yr) . Caries diagnosis was based on polarized light microscopy and contact microradiography of thin sections cut through the sample sites . Fifty-seven percent of sites (37/60) showed histological evidence of demineralization . Both the isolation frequency and the mean percentage viable count of mutans streptococci and Actinomyces viscosus were higher at sites with early caries, although mutans streptococci could not be detected at 37% of sites with early caries . At these latter sites, the proportions of Veillonella were markedly reduced . Lactobacilli were rarely isolated and were never recovered from caries-free surfaces . Analysis of the data shows that the relationship between plaque bacteria and enamel is neither merely passive nor indifferent, and that particular stages of lesion formation may be associated with different combinations of bacteria.

J Dent Res, 1989 Jul, 68(7), 1146 - 50
The effect of pH on the sensitivity of species of Lactobacillus to chlorhexidine and the antibiotics minocycline and spiramycin; Cleghorn B et al.; The purpose of this study was to determine the sensitivity of a range of Lactobacillus species to chlorhexidine, Minocycline, and Spiramycin, at a range of pH from 5.0 to 7.4 . Strains of Streptococcus were also tested for their sensitivity to chlorhexidine, as a comparison between the genera . There were both inter- and intra-species variations in the sensitivity of these strains to chlorhexidine . The strains tested were sensitive at pH 6.7 to the following levels of chlorhexidine (micrograms/mL): L . casei (6 strains), 10-60; L . plantarum (4 strains), 40; L . fermentum (13 strains), 2-20; L . brevis (1 strain), 10; and L . acidophilus (3 strains), 10-60 . The Streptococcus species were sensitive to 1-4 micrograms/mL (13 strains); 4-10 micrograms/mL (3 strains); and 10-20 micrograms/mL (2 strains) . One strain was able to survive 20 micrograms/mL . Chlorhexidine was found to be less effective at lower pH levels . The following examples show sensitivity (micrograms/mL) at pH 6.5 followed by sensitivity at pH 5.0: L . casei (ATCC 15008), 40,60; L . plantarum (CH 374), 40,100; L . fermentum (CH 324) 10,40; L . acidophilus (ATCC 4356), 10,40; and S . mutans (BM 52), 2,2 . All of the strains of Lactobacillus tested with Spiramycin were resistant at pH 5.0 . Minocycline was less affected by changes in pH, but at pH 7.4 Lactobacillus strains were more resistant to Minocycline as compared with Spiramycin . Both of these antibiotics are bacteriostatic, and therefore may have a more limited effect than a bactericidal agent such as chlorhexidine . The Lactobacillus strains tested required higher concentrations of chlorhexidine than did the strains of Streptococcus for a killing effect in vitro.

Clin Prev Dent, 1989 Jul-Aug, 11(4), 12 - 7
Salivary testing to reduce sugar consumption in school children; Abrams RA et al.; A total of 423 elementary and middle school children participated in a project to see if it would be possible to reduce their sugar consumption . Children tested their salivary lactobacillus colony count and buffering capacity in their health/science class, and they used this information to measure their caries risk . Because the lactobacillus colony count is a good indicator of a person's recent sugar consumption, any change in sugar consumption will produce a change in the lactobacillus colony count . Children's saliva was tested four times, and an intensive dietary counseling program was provided in the classroom . Results showed that lactobacillus counts went down, and the children reduced their sugar consumption.

Appl Environ Microbiol, 1989 Jul, 55(7), 1848 - 51
Lactobacilli and bile salt hydrolase in the murine intestinal tract; Tannock GW et al.; Mice that have a complex intestinal microflora but that do not harbor lactobacilli were used to determine the contribution of lactobacilli to the total bile salt hydrolase activity in the murine intestinal tract . Bile salt hydrolase activity in the ileal contents of these mice was reduced 86% in the absence of lactobacilli and by greater than 98% in the absence of lactobacilli and enterococci compared with samples from conventional mice . Bile salt hydrolase activities were lower in ileal and cecal contents from lactobacillus-free mice colonized with enterococci than in samples from lactobacillus-free mice colonized with lactobacilli . Bile salt hydrolase activity in the duodena, jejuna, ilea, and ceca of reconstituted lactobacillus-free mice colonized by lactobacilli was similar to that in samples from the intestinal tracts of conventional mice . We conclude from these studies that lactobacilli are the main contributors to total bile salt hydrolase activity in the murine intestinal tract.

Nucleic Acids Res, 1989 Jun 12, 17(11), 4217 - 22
The stereoselective enzymatic synthesis of 9-beta-D-2'-deoxyribofuranosyl 1-deazapurine; Betbeder D et al.; The transfer of 2-deoxyribose from thymidine to 1-deazapurine which is catalysed by N-deoxyribosyl transferases from Lactobacillus leichmanii occurs in high yield . This is a very stereoselective process and only one product, 9-beta-D-2'-deoxyribofuranosyl 1-deazapurine, is formed . Nmr spectroscopy, and in particular, nuclear Overhauser enhancement experiments, confirm that the 2-deoxyribose moiety is bound to N-9 rather than N-7 and that the glycosidic link has the beta-configuration.

J Biol Chem, 1989 Jun 5, 264(16), 9145 - 8
Expression of human thymidylate synthase in Escherichia coli; Davisson VJ et al.; A cDNA clone encoding thymidylate synthase (TS) has been isolated from a human T-cell library and modified in the 5'-untranslated region to incorporate several unique cloning sites . The gene has been cloned as a cassette into several Escherichia coli expression vectors which did not provide detectable amounts of the enzyme . A successful approach used a constitutive E . coli expression vector developed for the enzyme from Lactobacillus casei . A 115-base pair 5'-untranslated region from the L . casei TS which contains a ribosomal binding site and other regulatory sequences has been fused to the coding region of the human TS gene to provide a construct that is expressed in E . coli . The level of expression was further enhanced by altering the nucleotide sequence of the first 90 base pairs to accommodate common codon use in E . coli . In our best expression system, catalytically active human TS is expressed to a level that represents about 1.6% of the total soluble protein . The recombinant human TS has been purified and characterized; except for the presence of an amino-terminal blocking group, the enzyme has physical and kinetic properties similar to the enzyme isolated from human cells.

J Biol Chem, 1989 Jun 5, 264(16), 9391 - 9
Hydride transfer by dihydrofolate reductase . Causes and consequences of the wide range of rates exhibited by bacterial and vertebrate enzymes; Beard WA et al.; Transient and steady-state kinetics have been examined for dihydrofolate reductase (DHFR) from a number of sources . Rates of hydride transfer at pH 7.65 cover a wide range, from 7 s-1 for DHFR from a strain of Lactobacillus casei (LCDHFR1) to 3000 s-1 for recombinant human DHFR (rHDHFR) . In all cases as the pH is increased from 7 to 10, Vmax for the steady-state reaction decreases, and DVmax, the primary isotope effect, increases . This indicates a decrease in the rate of hydride transfer with increasing pH . The cross-over points, at which rates of product release and hydride transfer become equal, were calculated to occur at DVmax = 2.34 . The higher the rate of hydride transfer at pH 7.65, the higher the pH of the cross-over point . For LCDHFR1 the low rate of hydride transfer results in this process being partially rate-limiting for the steady-state reaction even at pH 5, with a cross-over point at about pH 7 . At pH 7.65 the burst phase associated with the initial conversion of enzyme-bound substrates to enzyme-bound products has an isotope effect of 3 or higher for LCDHFR and for DHFR from Escherichia coli (ECDHFR) . In contrast, the vertebrate DHFRs (bovine, BDHFR; chicken, CDHFR; and rHDHFR) exhibit a burst of product formation which is only partially limited by hydride transfer at this pH (Dkb: 2.3, 2.2, and 2.1, respectively) . An obligatory isomerization of the ternary substrate complex or of the ternary product complex is postulated to be partially rate-limiting for the vertebrate enzymes . At pH 5 LCDHFR1 and ECDHFR also exhibit evidence of such a rate-limiting obligatory conformational transition of the substrate or product ternary complex.

Antibiot Khimioter, 1989 Jun, 34(6), 433 - 7
{Influence of enterococci on the recovery of intestinal microflora changed by antibiotic therapy and carbohydrate nutrition}; Korshunov VM et al.; The process of intestinal microflora normalization after a course of antibiotic therapy was studied on mice and in persons with using S . faecium UDS-86 . It was shown that oral inoculation of strain UDS-86 influenced correction of the intestinal microflora in the mice and persons after the antibiotic therapy and carbohydrate nutrition . Oral inoculation of S . faecium UDS-86 resulted in lower quantities of potentially pathogenic organisms and higher levels of lactobacteria in the intestine at the background of dysbacteriosis induced by the antibiotic therapy and carbohydrate nutrition . Possible development of a preparation, eubiotic based on S . faecium UDS-86 is discussed.

Appl Environ Microbiol, 1989 Jun, 55(6), 1653 - 5
Complete nucleotide sequence and characterization of a cryptic plasmid from Lactobacillus helveticus subsp . jugurti; Takiguchi R et al.; A small cryptic plasmid, pLJ1, was isolated from Lactobacillus helveticus subsp . jugurti and was cloned into Escherichia coli HB101 by using pBR329 as a vector . Plasmid pLJ1 was 3,292 base pairs long and had single restriction endonuclease sites for PvuII, KpnI, AvaII, Acci, HindIII, and EcoRI . In a maxicell system, pLJ1 produced a protein of about 41 kilodaltons.

Plant Foods Hum Nutr, 1989 Jun, 39(2), 169 - 77
Effect of fermentation on protein, fat, minerals and thiamine content of pearl millet; Khetarpaul N et al.; Natural as well as single, mixed and sequential pure culture (S . diastaticus, S . cerevisiae, L . brevis and L . fermentum) fermentations of pearl millet flour for 72 h lowered pH and raised titratable acidity . The fermentation either decreased or did not change the protein content of pearl millet flour . Natural fermentation increased whereas pure culture fermentation decreased the fat content . Ash content did not change . Natural fermentation at 20 degrees C and 25 degrees C increased whereas at 30 degrees C it decreased the thiamine content of the pearl millet flour . Yeast fermentation raised the level of thiamine two- to three-fold, while lactobacilli fermentation lowered it significantly.

What Is Nitrification?, What Is Cell Biology?, What Is Bioremediation?, What Is Staphylococcus Aureus?, What Is Pcr?, o, Microbe, e, Bacteriology, i, Microbiology, c, Microbes, c, Bacteria, s, Penicillin, i, Brevibacteria, o, Microbial, i, Escherichia coli, e, Streptococcal, c, Growth media, a, Klebsiella, c, Gram negative, r, Bacteriological, s, Escherichia coli, a, Antimicrobial, c, Bacteriological, a, Staphylococcus aureus, s, S. cerevisiae, e, Antibiotics, o, Cell cultures, i, Yeasts, o, Microorganisms, e, Yeasts, a, Waste treatment, r, S. cerevisiae

Scientific Publications - Work Done by Microbiology Reader Bioscreen C
Agricultural Microbiology Anaerobic Microbiology Antimicrobial Susceptibility Artificial Atmosphere Bioassay of Antibiotics Biofilm Microbiology Bioreactor Technology Biotechnology Cell Biology Clinical Microbiology Environmental Microbiology Experiments with Yeast	Fermentation Food Microbiology Functional Genomics Gene Technology Growth Media Development Growth Rate and Lag Time Industrial Microbiology Medical/Pharmaceutical Field Microbiological Assay Microbiological Research Microbiology of Cosmetics go to a specific theme...	Military Microbiology Molecular Microbiology Mutagenicity and Genotoxicity Oral Microbiology Patents Postantibiotic Studies Soil Microbiology Spore Microbiology Veterinary Microbiology Waste/Wastewater Treatment Water Microbiology Wine Microbiology

� 2005 Transgalactic Ltd (manufacturer of Bioscreen C software) | Privacy Statement | P.O. Box 1393, 00101 Helsinki, Finland, phone: +358 9 85172920, fax: +358 9 8749481, e-mail: microbiology@bionewsonline.com

Last modified: May 25, 2005