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PubMed2003

Consensus-degenerate hybrid oligonucleotide primers for amplification of priming glycosyltransferase genes of the exopolysaccharide locus in strains of the Lactobacillus casei group.

A primer design strategy named CODEHOP (consensus-degenerate hybrid oligonucleotide primer) for amplification of distantly related sequences was used to detect the priming glycosyltransferase (GT) gene in strains of the Lactobacillus casei group. Each hybrid primer consisted of a short 3' degenerate core based on four highly conserved amino acids and a longer 5' consensus clamp region based on six sequences of the priming GT gene products from exopolysaccharide (EPS)-producing bacteria. The hybrid primers were used to detect the priming GT gene of 44 commercial isolates and reference strains of Lactobacillus rhamnosus, L. casei, Lactobacillus zeae, and Streptococcus thermophilus. The priming GT gene was detected in the genome of both non-EPS-producing (EPS(-)) and EPS-producing (EPS(+)) strains of L. rhamnosus. The sequences of the cloned PCR products were similar to those of the priming GT gene of various gram-negative and gram-positive EPS(+) bacteria. Specific primers designed from the L. rhamnosus RW-9595M GT gene were used to sequence the end of the priming GT gene in selected EPS(+) strains of L. rhamnosus. Phylogenetic analysis revealed that Lactobacillus spp. form a distinctive group apart from other lactic acid bacteria for which GT genes have been characterized to date. Moreover, the sequences show a divergence existing among strains of L. rhamnosus with respect to the terminal region of the priming GT gene. Thus, the PCR approach with consensus-degenerate hybrid primers designed with CODEHOP is a practical approach for the detection of similar genes containing conserved motifs in different bacterial genomes.

Amino Acid Sequence↗

PubMed1993

Effects of feeding premature infants with Lactobacillus GG on gut fermentation.

The study aimed to find out whether gut colonisation of premature babies with a probiotic, Lactobacillus GG, modified enteric carbohydrate fermentation. Twenty preterm infants were randomised to receive Lactobacillus GG 10(8) colony forming units twice a day for two weeks or to a control group. Faecal short chain fatty acids (SCFAs), ethanol, and urinary 2,3-butanediol, were measured in parallel with microbiological studies. Lactobacillus GG colonised nine babies. From 1-28 days of age faecal SCFAs did not differ significantly from controls. Median and ranges were (treated and controls, respectively): acetic acid: 173 (trace-799), 166 (trace-700); propionic acid: 44 (trace-169), 37 (11-229); butyric acid: 31 (5-107), 37 (2-118) mumol/g dry weight. Ethanol was detected in more faecal samples from treated babies (65% v 37%), and at higher concentration (6.3 (trace-40) v 3.3 (0.6-8.8; one 229) mumol/g). 2,3-Butanediol was found in 66% of urine samples from treated babies and 58% from controls. On 83% of these occasions Klebsiella sp, Enterobacter sp, or Serratia sp were cultured from faeces. Lactobacillus GG had no obvious adverse effects on nutritionally important SCFAs. The small increase in ethanol excretion is unlikely to have clinical significance.

Anti-Bacterial Agents↗

PubMed2006

Lactobacillus plantarum gene clusters encoding putative cell-surface protein complexes for carbohydrate utilization are conserved in specific gram-positive bacteria.

BACKGROUND: Genomes of gram-positive bacteria encode many putative cell-surface proteins, of which the majority has no known function. From the rapidly increasing number of available genome sequences it has become apparent that many cell-surface proteins are conserved, and frequently encoded in gene clusters or operons, suggesting common functions, and interactions of multiple components. RESULTS: A novel gene cluster encoding exclusively cell-surface proteins was identified, which is conserved in a subgroup of gram-positive bacteria. Each gene cluster generally has one copy of four new gene families called cscA, cscB, cscC and cscD. Clusters encoding these cell-surface proteins were found only in complete genomes of Lactobacillus plantarum, Lactobacillus sakei, Enterococcus faecalis, Listeria innocua, Listeria monocytogenes, Lactococcus lactis ssp lactis and Bacillus cereus and in incomplete genomes of L. lactis ssp cremoris, Lactobacillus casei, Enterococcus faecium, Pediococcus pentosaceus, Lactobacillius brevis, Oenococcus oeni, Leuconostoc mesenteroides, and Bacillus thuringiensis. These genes are neither present in the genomes of streptococci, staphylococci and clostridia, nor in the Lactobacillus acidophilus group, suggesting a niche-specific distribution, possibly relating to association with plants. All encoded proteins have a signal peptide for secretion by the Sec-dependent pathway, while some have cell-surface anchors, novel WxL domains, and putative domains for sugar binding and degradation. Transcriptome analysis in L. plantarum shows that the cscA-D genes are co-expressed, supporting their operon organization. Many gene clusters are significantly up-regulated in a glucose-grown, ccpA-mutant derivative of L. plantarum, suggesting catabolite control. This is supported by the presence of predicted CRE-sites upstream or inside the up-regulated cscA-D gene clusters. CONCLUSION: We propose that the CscA, CscB, CscC and CscD proteins form cell-surface protein complexes and play a role in carbon source acquisition. Primary occurrence in plant-associated gram-positive bacteria suggests a possible role in degradation and utilization of plant oligo- or poly-saccharides.

Antigens, Surface↗

PubMed1998

[The measurement of growth curve and generation time of lactobacillus]

OBJECTIVE:The purpose of this test was to understand the growth pattern of lactobacillus for the research of its cariogenicity. METHODS: The growth quantity of lactobacillus which was culture in a constant condition was measured periodically by spectrophotometry and flora counting,and its growth curve and generation time were measured. RESULTS: It was found that the logarithmic phase of lactobacillus was 6-16 hours after it was cultured.And its generatin time was 54 minutes. CONCLUSIN: The growth curve of lactobacillus was in accordance with streptococcus mutan.

Journal Article↗

PubMed2006

Decreased gum bleeding and reduced gingivitis by the probiotic Lactobacillus reuteri.

The primary aim of this study was to assess if the probiotic Lactobacillus reuteri could be effective in the treatment of gingivitis and further to evaluate the influence of the probiotic on plaque and the lactobacilli population in the saliva. A randomised, placebo-controlled, double blind study was performed over 2 weeks. Fifty-nine patients with moderate to severe gingivitis were included and given one of two different Lactobacillus reuteri formulations (LR-1 or LR-2) at a dose of 2 x 10(8) CFU per day, or a corresponding placebo. At baseline (day 0) gingival index and plaque index were measured on two surfaces and saliva for lactobacilli determination was collected. The patients were instructed how to brush and floss efficiently and study treatment was started.The patients returned on day 14 for final assessment of gingivitis and plaque and saliva was collected. 20 patients were randomised to LR-1, 21 to LR-2 and 18 to placebo. Gingival index fell significantly in all 3 groups (p < 0.0001). LR-1, but not LR-2 improved more than placebo (p < 0.0001). Plaque index fell significantly in LR-1 (p < 0.05) and in LR-2 (p < 0.01) between day o and day 14 but there was no significant change in the placebo group. At day 14, 65% of the patients in LR-1 were colonised with Lactobacillus reuteri and 95% in the LR-2 group. Lactobacillus reuteri was efficacious in reducing both gingivitis and plaque in patients with moderate to severe gingivitis.

Chewing Gum↗

PubMed2024

Vaginal Lactobacillus fatty acid response mechanisms reveal a metabolite-targeted strategy for bacterial vaginosis treatment.

Bacterial vaginosis (BV), a common syndrome characterized by Lactobacillus-deficient vaginal microbiota, is associated with adverse health outcomes. BV often recurs after standard antibiotic therapy in part because antibiotics promote microbiota dominance by Lactobacillus iners instead of Lactobacillus crispatus, which has more beneficial health associations. Strategies to promote L. crispatus and inhibit L. iners are thus needed. We show that oleic acid (OA) and similar long-chain fatty acids simultaneously inhibit L. iners and enhance L. crispatus growth. These phenotypes require OA-inducible genes conserved in L. crispatus and related lactobacilli, including an oleate hydratase (ohyA) and putative fatty acid efflux pump (farE). FarE mediates OA resistance, while OhyA is robustly active in the vaginal microbiota and enhances bacterial fitness by biochemically sequestering OA in a derivative form only ohyA-harboring organisms can exploit. OA promotes L. crispatus dominance more effectively than antibiotics in an in vitro BV model, suggesting a metabolite-based treatment approach.

Vaginosis, Bacterial↗

PubMed1992

Hydrogen peroxide production by Lactobacillus species: correlation with susceptibility to the spermicidal compound nonoxynol-9.

Facultative anaerobic lactobacilli were recovered from the vaginas of 96.8% of 63 nonpregnant, healthy, premenopausal women. The predominant species were Lactobacillus jensenii, Lactobacillus acidophilus, and Lactobacillus casei. Of the women, 74.6% had hydrogen peroxide-producing lactobacilli, 22.2% had non-hydrogen peroxide-producing lactobacilli, and 3.2% had no lactobacilli. None of the 68 isolates had catalase activity. Some 68.2% of the isolates were inhibited by concentrations of less than or equal to 1% (wt/vol) of nonoxynol-9 (bactericidal for 73.3% of isolates, bacteriostatic for 26.7%). The remaining 31.8% could grow in all concentrations to 25% (wt/vol) of nonoxynol-9. All of the lactobacilli that were sensitive to nonoxynol-9 produced hydrogen peroxide whereas only 3 of 21 resistant strains were hydrogen peroxide producers. A significant correlation (P less than .001, chi 2 test) was found between hydrogen peroxide production and sensitivity to nonoxynol-9. It is suggested that the vaginal flora of spermicide users could be depleted of hydrogen peroxide-producing lactobacilli, possibly increasing susceptibility to urogenital infection.

Adult↗

PubMed2006

Effects of Lactobacillus strains on cancer cell proliferation and oxidative stress in vitro.

AIMS: The objective of this study was to assess in vitro, whether heat-killed (HK) lactic acid bacteria cells and fractionations of HK cells could suppress the viability of human cancer cells and inhibit the cytotoxicity associated with oxidative stress. METHODS AND RESULTS: Among the strains, the HK cells of Lactobacillus acidophilus 606 and Lactobacillus casei ATCC 393 exhibited the most profound inhibitory activity in all of the tested cell lines. HK cells of L. acidophilus 606 were determined to be less toxic to healthy human embryo fibroblasts (hEF cells) than were HK cells of L. casei ATCC 393. The soluble polysaccharides from L. acidophilus 606 evidenced the most effective anticancer activity, but inhibited hEF cell growth by only 20%. The soluble polysaccharides from L. acidophilus 606 were partly observed to induce apoptosis in the HT-29 cells by DNA fragmentation and propidium iodine staining. Both the HK cells of L. acidophilus 606 and the soluble polysaccharide components of this strain also exhibited potent antioxidative activity. CONCLUSIONS: Our findings suggest that the soluble polysaccharide fraction from L. acidophilus 606 may constitute a novel anticancer agent, which manifests a high degree of selectivity for human cancer cells and antioxidative agent in the food industry. SIGNIFICANCE AND IMPACT OF THE STUDY: These soluble polysaccharide components from Lactobacillus may be applied to various foods, and used as adjuncts for cancer therapy and prevention.

Antineoplastic Agents↗

PubMed1994

Identification and purification of a protein that induces production of the Lactobacillus acidophilus bacteriocin lactacin B.

Lactacin B is a heat-stable bacteriocin produced by Lactobacillus acidophilus N2 that is active against closely related lactobacilli, including Lactobacillus delbrueckii subsp. lactis (formerly Lactobacillus leichmannii) ATCC 4797. Pure producer cultures propagated in MRS broth (initial pH 6.5) contain no lactacin B; it is detected only in cultures maintained at pH 5.0 to 6.0 and produced optimally at pH 6.0 S. F. Barefoot and T. R. Klaenhammer, Antimicrob. Agents Chemother. 26:328-334, 1984). Associative growth of producer and indicator, L. delbrueckii subsp. lactis ATCC 4797, resulted in production of an inhibitor identical to lactacin B. Associative growth increased lactacin B production from nondetectable levels (< 100 activity units [AU]/ml) to between 3,200 and 6,400 AU/ml in MRS broth (initial pH 6.5) and resulted in early but equal production of lactacin B (approximately 25,600 AU/ml) in broth maintained at pH 6.0. Indicator cells, but not spent culture filtrates, induced lactacin B production. Indicator cells disrupted by a French pressure cell yielded cell-free filtrates containing inducing activity. Chromatofocusing and gel filtration high-performance liquid chromatography of cell-free filtrates yielded a protein with a pI of 4.1 and a molecular size of approximately 58 kDa that induced lactacin B production. Analytical isoelectric focusing yielded a single protein band. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels contained a 28-kDa protein suggesting a two-subunit structure. Protein sequencing identified an N-terminal serine and 18 additional amino acids. To our knowledge, there are not previous descriptions of proteins that induce bacteriocin production in lactic acid bacteria.

Amino Acid Sequence↗

PubMed1963

TEMPERATURE-SENSITIVE DEXTRANSUCRASE SYNTHESIS BY A LACTOBACILLUS.

Dunican, L. K. (Cornell University, Ithaca, New York), and H. W. Seeley, Jr. Temperature-sensitive dextransucrase synthesis by a lactobacillus. J. Bacteriol. 86:1079-1083. 1963.-Dextran synthesis was found to be temperature-dependent in Lactobacillus strain RWM-13. Dextran was not formed above 37 C, although growth of cells occurred up to 42 C. Logarithmically growing cells transferred from 30 C to 40 C ceased producing dextran while growth decreased nominally. An examination of the extracts of cells broken by sonic treatment showed that as the temperature of growth was increased above 37 C the production of dextransucrase decreased. By use of an inhibitor of invertase, 10(-4)m AgNO(3), it was shown that invertase replaced dextransucrase activity at temperatures above 37 C. In contrast to dextransucrase in Leuconostoc mesenteroides, the enzyme in Lactobacillus strain RWM-13 was constitutive and thus resembled that of Streptococcus bovis. Thermosensitivity of dextransucrase synthesis has not been observed in Leuconostoc or Streptococcus.

Dextrans↗

PubMed1965

CONVERSION OF D-BIOTIN TO BIOTIN VITAMERS BY LACTOBACILLUS ARABINOSUS.

Birnbaum, Jerome (University of Cincinnati College of Medicine, Cincinnati, Ohio), and Herman C. Lichstein. Conversion of d-biotin to biotin vitamers by Lactobacillus arabinosus. J. Bacteriol. 89:1035-1040. 1965.-Saccharomyces cerevisiae utilizes d-biotin, biotin sulfoxide, and several vitamers of biotin, whereas Lactobacillus arabinosus responds to biotin and biotin sulfoxide of the naturally occurring forms of the vitamin. The use of these organisms for differential assay permitted investigation into possible conversion of d-biotin to vitamers of biotin by cells of L. arabinosus. Cells were grown in modified Wright-Skeggs medium containing several levels of biotin. No differences were detected between the assays for free intracellular or bound biotin up to 48 hr of growth. However, at 15 to 16 hr, in media containing an excess of biotin, the lactobacillus assay value for menstruum biotin dropped markedly, whereas the yeast assay showed no change. This suggested that biotin was converted to vitamers not active for L. arabinosus. The biotin-converting system appears to have characteristics of an enzyme system, i.e., a temperature optimum at 37 C, a broad pH optimum of 4.3 to 6.5, and requirements for Mg and Mn ions. Experiments suggest that increasing hydrogen ion concentration is a major physiological mechanism controlling the formation of this system. The vitamers were separated chromatographically and were found to have R(F) values of 0.44 and 0.94, and are combinable and uncombinable with avidin, respectively. The physiological role of biotin conversion is discussed in relation to control of cell populations in cultures of L. arabinosus.

Biological Assay↗

PubMed1996

Homofermentative Lactobacillus species predominantly isolated from canine feces.

Lactobacillus salivarius group biovars VIa and VIb, which are homofermentative Lactobacillus, were predominantly isolated from canine feces. Identification and biotyping of L. salivarius group biovars VIa and VIb were originally done by Mitsuoka et al. (1976). These strains were tentatively identified as L. salivarius by their phenotypic characteristics. They are, however, more similar to those of some new Lactobacillus species, particularly L. animalis and L. murinus, than those of L. salivarius and have now been identified as L. animalis by DNA-DNA homology.

Animals↗

PubMed1979

Prophylaxis against ampicillin-associated diarrhea with a lactobacillus preparation.

The efficacy of a lactobacillus preparation (Lactinex) in preventing ampicillin-associated diarrhea in adult inpatients was studied. In a double-blind procedure, 98 patients were assigned randomly to receive one packet of Lactinex (Lactobacillus acidophilus and L bulgaricus) or placebo four times daily for the first five days of ampicillin therapy. Cases of diarrhea were reviewed independently and classified according to etiology. Complete data were obtained for 79 patients--43 received placebo and 36 received Lactinex. Diarrhea occurred in nine (21%) patients receiving placebo and in three (8.3%) patients receiving Lactinex; the difference was not statistically significant (p = 0.21, Fisher's Exact Test). When the patients with diarrhea unrelated to ampicillin were excluded (50%), the incidence of ampicillin-induced diarrhea in the placebo group (14%) was significantly greater (p = 0.03, Fisher's Exact Test) than in the Lactinex group (0%). Prophylactic administration of lactobacillus preparations may be effective in preventing ampicillin-induced diarrhea; however, prophylactic administration appears to be justified, on a cost/benefit basis, only in patients with a history of antibiotic-induced diarrhea.

Adult↗

PubMed2004

Strain improvement and metabolic flux analysis in the wild-type and a mutant Lactobacillus lactis strain for L(+)-lactic acid production.

The effects of initial glucose concentration and calcium lactate concentration on the lactic acid production by the parent strain, Lactobacillus lactis BME5-18, were studied. The results of the experiments indicated that glucose and lactate repressed the cell growth and the lactic acid production by Lactobacillus lactis BME5-18. A L(+)-lactic acid overproducing strain, Lactobacillus lactis BME5-18M, was screened by mutagenizing the parent strain with ultraviolet (UV) light irradiation and selecting the high glucose and lactate calcium concentration repression resistant mutant. Starting with a concentration of 100g L(-1) glucose, the mutant produced 98.6 g L(-1) lactic acid after 60 h in flasks, 73.9% higher than that of the parent strain. The L(+)-lactic acid purity was 98.1% by weight based on the amount of total lactic acid. The culture of the parent strain could not be analyzed well by conventional metabolic flux analysis techniques, since some pyruvate were accumulated intracellularly. Therefore, a revised flux analysis method was proposed by introducing intracellular pyruvate pool. Further studies demonstrate that there is a high level of NADH oxidase activity (12.11 mmol mg(-1) min(-1)) in the parent strain. The molecular mechanisms of the strain improvement were proposed, i.e., the high level of NADH oxidase activity was eliminated and the uptake rate of glucose was increased from 82.1 C-mmol (g DW h)(-1) to 98.9 C-mmol (g DW h)(-1) by mutagenizing the parent strain with UV, and therefore the mutant strain converts mostly pyruvate to lactic acid with a higher productivity (1.76 g L(-1) h(-1)) than the parent strain (0.95 g L(-1) h(-1)).

Computer Simulation↗

PubMed2001

Specific IgA to lactic acid bacteria in feces of children consuming milk fermented by yoghurt symbiosis and Lactobacillus casei (Danone strain DN 114 001).

An immunoreactive role of lactic acid bacteria established in animals has seldom been investigated in humans. In a large-scale clinical study, children from day-care centers received either yoghurt (Y), milk fermented by yoghurt symbiosis and Lactobacillus casei (DN 114 001) (YC), or gelified milk (GM) as diet supplements during two 30-day supplementation periods separated by one 30-day period without supplementation. Feces samples were collected before, during, and after the 2nd supplementation period. Proteins were extracted in a buffer containing enzymatic inhibitors. IgA levels were assessed and adjusted to the weight of feces samples. Specific IgA to lactic acid bacteria strains (Streptococcus thermophilus 8901A, 8902A; Lactobacillus bulgaricus; Lactobacillus casei) present in Y and YC were assayed in ELISA and adjusted to individual IgA levels. Mean levels of fecal IgA were within reported ranges for pediatric populations of similar age. IgA levels decreased significantly but transiently in children receiving Y, and increased significantly in children receiving GM, but did not vary in the group of children who were given YC. Specific IgA to the 4 strains tested increased significantly during the supplementation period only in the group of children receiving GM, while it was transient and not significant in children receiving YC. No variation was noted in children given Y Specific IgA to lactic acid bacteria can be assayed in feces. Supplementation with fermented milks might induce a mucosal tolerance to environmental flora.

Animals↗

PubMed1995

Cloning and characterization of brnQ, a gene encoding a low-affinity, branched-chain amino acid carrier in Lactobacillus delbrückii subsp. lactis DSM7290.

A gene (brnQ), encoding a carrier for branched-chain amino acids in Lactobacillus delbrückii subsp. lactis DSM7290 was cloned in the low-copy-number vector pLG339 by complementation of a transport-deficient Escherichia coli strain. The plasmid carrying the cloned gene restored growth of an E. coli strain mutated in 4 different branched-chain amino acid transport genes at low concentrations of isoleucine, and increased its sensitivity to valine. Transport assays showed that leucine, isoleucine and valine are transported by this carrier and that transport is driven by the proton motive force. Nucleotide sequence analysis revealed an open reading frame of 1338 bp encoding a hydrophobic protein of 446 amino acids with a calculated molecular mass of 47864 Daltons. The start site of brnQ transcription was determined by primer extension analysis using mRNA from Lactobacillus delbrückii subsp. lactis DSM7290. The hydropathy profile suggests the existence of at least 12 hydrophobic domains that probably form membrane-associated alpha-helices. Comparisons of the nucleotide sequence of brnQ from Lactobacillus delbrückii subsp. lactis DSM7290, the amino acid sequence of its product and the topology of the hydrophobic domains with those of the respective carrier genes and proteins of Salmonella typhimurium and Pseudomonas aeruginosa revealed extensive homology.

Amino Acid Sequence↗

PubMed1992

Effect of fermented oatmeal soup on the cholesterol level and the Lactobacillus colonization of rat intestinal mucosa.

Rats were fed with freeze-dried oatmeal soup fermented by six different Lactobacillus strains from rat and man; the formula is intended for enteral feeding. The serum cholesterol levels after 10 d were lower for rats eating oatmeal as compared to a commercial product, Biosorb Sond. Colonizing ability of the administered strains were evaluated in vivo. Only Lactobacillus reuteri R21c were able to, effectively, colonizing the mucosa; it represented about 30% of the Lactobacillus population 24 d after termination of the administration. L. reuteri R21c was easily recognized by the ability to produce a yellow pigment on agar plates. The identity was confirmed by carbohydrate fermentations (API 50CH), plasmid pattern and endonuclease restriction analysis of the chromosomal DNA.

Animals↗

PubMed2006

Prevention of nephrolithiasis by Lactobacillus in stone-forming rats: a preliminary study.

Hyperoxaluria is a risk factor for renal stones. It appears to be sustained by increased dietary load or increased intestinal absorption. The aim of this study was to evaluate whether oral administration of lactobacilli could prevent urolithiasis in stone-forming rats. Oxalate-degrading activities of lactobacilli were evaluated by measuring the oxalate level in a culture medium after inoculation with lactobacilli. Only the strains of Lactobacillus having oxalate-degrading activity were used. Sprague-Dawley rats were fed a powdered standard diet containing 3% sodium oxalate and/or received 100 mg/kg of celecoxib for the first 8 days by gavage, before or after the beginning of this experiment (groups with previous treatment or with co-treatment). Rats were sacrificed after 4 weeks and kidneys were harvested for the assay of crystal formation under a dissecting microscope. Twenty-four-hour urine collections were performed before kidney harvest. Only two strains, Lactobacillus casei HY2743 and L. casei HY7201 out of 31 strains of Lactobacillus were able to degrade oxalate. In both groups of co-treatment and previous treatment with L. casei HY2743 and L. casei HY7201, urine oxalate excretion decreased compared to the group without lactobacilli. The dissecting microscope examination of kidneys in the rats in two previous treatment groups and the co-treatment group with L. casei HY7201 showed less abundant crystals than control groups. Our results show that lactobacilli may be used as a potential therapeutic strategy in the prevention of urinary stones.

Animals↗