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PubMed2005

Influence of cooling temperature and duration on cold adaptation of Lactobacillus acidophilus RD758.

The effect of different cooling temperatures and durations on resistance to freezing and to frozen storage at -20 degrees C in Lactobacillus acidophilus RD758 was studied, by using a central composite rotatable design. A cold adaptation was observed when the cells were maintained at moderate temperature (26 degrees C) for a long time (8h) before being cooled to the final temperature of 15 degrees C. These conditions led to a low rate of loss in acidification activity during frozen storage (0.64 minday(-1)) and a high residual acidification activity after 180 days of frozen storage (1011 min). The experimental design allowed us to determine optimal cooling conditions, which were established at 28 degrees C during 8h. Adaptation to cold temperatures was related to an increase in the unsaturated to saturated fatty acid ratio and in the relative cycC19:0 fatty acid concentration. Moreover, an increased synthesis of four specific proteins was observed as an adaptive response to the optimal cooling conditions. They included the stress protein ATP-dependent ClpP and two cold induced proteins: pyruvate kinase and a putative glycoprotein endopeptidase.

Acclimatization↗

PubMed1993

Influence of bile on cellular integrity and beta-galactosidase activity of Lactobacillus acidophilus.

The influence of bile on beta-galactosidase activity, cellular integrity, cellular retention of beta-galactosidase, and cellular permeability of five strains of Lactobacillus acidophilus was investigated. The five strains were also compared for bile tolerance. Two strains, 223 and 4356, were significantly less resistant to bile than the others (107, NCFM, and 606). beta-Galactosidase activity of all five strains was significantly higher in the presence of .3% oxgall than in its absence. Strain 107 showed the highest increase of enzyme activity in the presence of oxgall. Cells were not lysed in the presence of .3% oxgall, and beta-galactosidase was retained inside the cell even after extended incubation (60 min) in the presence of .3% oxgall. However, material that absorbed light at 260 nm leaked from the cells in the presence of oxgall. We concluded that, in the presence of bile, the permeability of cells of L. acidophilus increased, permitting more substrate to enter the cells, thus increasing the beta-galactosidase activity of whole cells.

Bile↗

PubMed1988

Impact of Lactobacillus acidophilus on the normal intestinal microflora after administration of two antimicrobial agents.

Twenty healthy volunteers participated in a comparative study concerning the influence of Lactobacillus acidophilus supplements on the normal intestinal microflora after the administration of two antimicrobial agents, enoxacin and clindamycin, respectively. L. acidophilus NCFB 1748 was given as a fermented milk product containing 5 x 10(8)-2 x 10(9) CFU/ml to ten of the volunteers immediately after the administration of the antimicrobial agents. On the seventh day of enoxacin administration enterobacteria were eliminated in nine of ten subjects. Enterococci disappeared or decreased significantly in five subjects. During the L. acidophilus supplementation, there was a significant increase in the number of Escherichia coli in one subject, while enterococci returned to the same level as before enoxacin administration in all subjects.

Adult↗

PubMed2000

Immediate effect of Lactobacillus acidophilus on the intestinal flora and fecal enzymes of rats and the in vitro inhibition of Escherichia coli in coculture.

The in vitro role of Lactobacillus acidophilus was investigated to explore the potential to inhibit coliforms. A threefold concentrated cell-free extract from L. acidophilus SBT2074 could efficiently inhibit most of the tested Gram-positive and Gram-negative bacteria. Among the three strains of L. acidophilus, SBT2062, SBT2071, and SBT2074, only L. acidophilus SBT2074 showed this inhibitory property. These three strains were also tested in coculture with Escherichia coli 3544 in skim milk medium. The fermentation could result in complete inhibition of E. coli in 36 h. Short-term administration of L. acidophilus SBT2074 in rats with and without E. coli resulted in significant inhibition of coliforms and anaerobes. The E. coli infected rats regained the normal flora in the presence of lactic acid bacteria. The fecal enzyme beta-glucuronidase activity was also decreased significantly when L. acidophilus SBT2074 was administered and was related to the decreased number of bacteria in the intestinal tract. The analysis of the small intestinal contents showed that the concentrations of coliforms in the duodenum, jejunum, and the ileum were significantly reduced by the administration of lactic acid bacteria. The effects are seen in a short period, suggesting that L. acidophilus SBT2074 fermentate may have clinical application for people suffering from gastrointestinal distress caused by coliforms.

Animals↗

PubMed1983

Colonization of Lactobacillus acidophilus in gnotobiotic chicks.

Germ-free chicks hatched in flexible film gnotobiotic isolators were dosed orally at 2 days of age with a pure culture of Lactobacillus acidophilus. The chicks monoassociated with L. acidophilus were killed at 2 weeks of age to obtain gastrointestinal tract specimens for histological sectioning. Both light microscopy and transmission electron microscopy were performed to determine colonization and adhesion of lactobacilli. This strain of L. acidophilus was found associated with epithelium from three segments of the gastrointestinal tract (crop, proventriculus, and duodenum) of the gnotobiotic chick. The electron micrographs showed not only a close relationship between the Lactobacillus organism and the crop epithelia, but also an attachment through physical contact.

Adhesiveness↗

PubMed1994

Heterodimeric deoxynucleoside kinases of Lactobacillus acidophilus R-26: functional assignment of subunits using limited proteolysis controlled by end-product inhibitors.

Heterodimeric quaternary structures for two enzyme complexes from Lactobacillus acidophilus R-26 exhibiting deoxycytidine kinase/deoxyadenosine kinase (I) and deoxyguanosine kinase/deoxyadenosine kinase(II) activities have been proven by the following steps: (1) separation of each complex into two components on SDS-PAGE at pH 6.6; (2) N-terminal amino acid sequencing of each component; (3) functional assignment of each component by differential limited proteolysis. The third step was facilitated by the finding that the binding of a specific end-product inhibitor dNTP, to each kinase active site makes the corresponding kinase subunit resistant to trypsin, while leaving the heterologous kinase subunit susceptible to proteolysis. Analysis on SDS-PAGE has revealed only two fragments (15.8 and 11.0 kDa) following proteolysis of dCyd kinase/dAdo kinase (I) with trypsin in the presence of dATP. This may indicate that the kinase polypeptide chain (27.2 kDa) not protected by dNTP is cut by trypsin at a single specific site, with concomitant loss of activity. Thus, this work presents a unique approach to the clarification of structure and function of enzymes composed of heterologous subunits.

Amino Acid Sequence↗

PubMed1993

Identification and classification of Lactobacillus acidophilus, L. gasseri and L. johnsonii strains by SDS-PAGE and rRNA-targeted oligonucleotide probe hybridization.

Thirty-two strains originally identified as Lactobacillus acidophilus and L. gasseri were screened for their taxonomic homogeneity by SDS-PAGE of whole-cell proteins. After numerical comparison of the resulting protein electrophoretic fingerprints, two well-delineated clusters were detected. The majority of the strains grouped in one electrophoretic cluster, which contained the type strain of L. acidophilus and corresponds to DNA group A1 of Johnson, J. L., Phelps, C. F., Cummins, C. S., London, J. & Gasser, F. (1980; International Journal of Systematic Bacteriology 30, 53-68). Another cluster corresponded to DNA group B. It contained two subclusters, which agreed perfectly with DNA subgroups B1 (L. gasseri) and B2 (L. johnsonii), respectively. The 23S rRNA genes were partially sequenced and 23S-rRNA-targeted oligonucleotide probes were designed for identification of DNA groups A1, B1 and B2. Probe Lbg reacted with all strains of electrophoretic cluster B1 (L. gasseri), probe Lbj hybridized with strains of cluster B2 (L. johnsonii) and probe Lba with strains of cluster A1 (authentic L. acidophilus). The probes were successfully used for the identification of strains belonging to the respective species. The phylogenetic relationship of a representative of L. johnsonii was determined by comparative sequence analysis of the 16S rRNA genes. It is very closely related to L. gasseri.

Bacterial Proteins↗

PubMed2005

Microarray analysis of a two-component regulatory system involved in acid resistance and proteolytic activity in Lactobacillus acidophilus.

Two-component regulatory systems are one primary mechanism for environmental sensing and signal transduction. Annotation of the complete genome sequence of the probiotic bacterium Lactobacillus acidophilus NCFM revealed nine two-component regulatory systems. In this study, the histidine protein kinase of a two-component regulatory system (LBA1524HPK-LBA1525RR), similar to the acid-related system lisRK from Listeria monocytogenes (P. D. Cotter et al., J. Bacteriol. 181:6840-6843, 1999), was insertionally inactivated. A whole-genome microarray containing 97.4% of the annotated genes of L. acidophilus was used to compare genome-wide patterns of transcription at various pHs between the control and the histidine protein kinase mutant. The expression pattern of approximately 80 genes was affected by the LBA1524HPK mutation. Putative LBA1525RR target loci included two oligopeptide-transport systems present in the L. acidophilus genome, other components of the proteolytic system, and a LuxS homolog, suspected of participating in synthesis of the AI-2 signaling compound. The mutant exhibited lower tolerance to acid and ethanol in logarithmic-phase cells and poor acidification rates in milk. Supplementation of milk with Casamino Acids essentially restored the acid-producing ability of the mutant, providing additional evidence for a role of this two component system in regulating proteolytic activity in L. acidophilus.

Bacterial Proteins↗

PubMed1992

[The effect of Lactobacillus acidophilus and Bifidobacterium bifidum on the intestinal ecosystem of the elderly patient].

The authors have tested the therapeutic efficacy of a multibacterial combination consisting of Lactobacillus acidophilus (10(9)) and Bifidobacterium bifidum (10(9)) in elderly patients with bowel disorders. Bacteriological and histopathologic investigation showed this combination to yield excellent biologic results with restoration of duodenal bacterial flora and subsidence of clinical symptoms. The function of the muciparous glands was restored and the duodenal mucosa was normalized.

Aged↗

PubMed1982

Immunisation of rhesus monkeys with Streptococcus mutans, Lactobacillus acidophilus and lipoteichoic acid for protection against dental caries.

An attempt was made to protect rhesus monkeys from dental caries by immunisation with Streptococcus mutans, Lactobacillus acidophilus and lipoteichoic acid (LTA). The vaccine composed of S. mutans gave significant protection against caries, a decrease in the number of S. mutans, an increase in IgG antibodies and a moderate increase in complement-fixing antibodies to LTA. When LTA was used as immunogen, there was only a small reduction in caries, without any detectable antibodies to LTA and a slight increase in IgG antibodies to cell of S. mutans. Vaccines of L. acidophilus or L. fermentum gave no protection. A combined vaccine of S. mutans and L. acidophilus did not reduce the incidence of caries but the antibody titre to cells of S. mutans was raised to a level comparable with that in the S. mutans-immunised monkeys. The results of this investigation in a subhuman primate confirm that immunisation with S. mutans induces protection against caries, unlike the attempt to immunise with two selected strains of lactobacilli. More studies are required to establish the role of specific serotypes of lactobacilli in the development of dental caries.

Animals↗

PubMed1992

Survival of Lactobacillus acidophilus and Bifidobacterium bifidum in ice cream for use as a probiotic food.

Probiotic ice cream was made by fermenting a standard ice cream mix with Lactobacillus acidophilus and Bifidobacterium bifidum cultures and then freezing the mix in a batch freezer. Survival of the L. acidophilus and B. bifidum, as well as beta-galactosidase activity, was monitored during 17 wk of frozen storage at -29 degrees C. After freezing of the fermented mix, bacterial counts were 1.5 x 10(8) cfu/ml for L. acidophilus and 2.5 x 10(8) cfu/ml for B. bifidum. Seventeen weeks after freezing, these counts had decreased to 4 x 10(6) and 1 x 10(7) cfu/ml, respectively. During the same period, beta-galactosidase activity decreased from 1800 to 1300 units/ml. Probiotic ice cream was prepared at pH 5.0, 5.5, and 6.0 to determine consumer preferences and was compared with standard Utah State University "Aggie" ice cream. All samples were strawberry-flavored and were evaluated by 88 judges. The preferred pH of probiotic ice cream, based on overall acceptance, was pH 5.5. We demonstrated that probiotic ice cream is a suitable vehicle for delivering beneficial microorganisms such as L. acidophilus and B. bifidum to consumers. The bacteria can be grown to high numbers in ice cream mix and remain viable during frozen storage.

Animals↗

PubMed1997

Nonlipopolysaccharide component(s) of Lactobacillus acidophilus stimulate(s) the production of interleukin-1 alpha and tumor necrosis factor-alpha by murine macrophages.

Previous studies in our laboratory suggested that Lactobacillus acidophilus strain DDS-1 (LA1) has a suppressive effect on chemically induced tumors in experimental animals. In an effort to understand the possible mechanisms underlying this effect, we investigated the ability of LA1 to induce the production of interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor-alpha (TNF-alpha), which have potent cytocidal and cytostatic effects on tumor cells. The mouse macrophage cell line RAW264.7 was incubated with live or heat-killed cells of four strains of L. acidophilus or Bifidobacterium bifidum. Escherichia coli was used as a source of lipopolysaccharide that is known to induce the above cytokines. The amount of the cytokines present in the culture fluid was quantitated by an enzyme-linked immunosorbent assay. LA1 induced the production of higher levels of IL-1 alpha and TNF-alpha than other lactobacilli and bifidobacteria. Stimulation of the production of the cytokines was not due to the lipopolysaccharide (LPS) component, since LPS at concentrations equivalent to, or 100-fold greater than, that of LA1 induced only negligible amounts of IL-1 alpha and TNF-alpha. These results reveal that non-LPS component(s) of LA1 stimulate(s) the production of IL-1 alpha and TNF-alpha by macrophages, indicating that this organism stimulates the production of immunologic factors.

Animals↗

PubMed1987

Frequency and occurrence of Lactobacillus acidophilus in the gut of the pig, as indicated by its presence in the faeces.

Faecal samples of 2 pigs, kept on a constant diet, were analysed for Lactobacillus acidophilus and other lactic acid bacteria at 1 week intervals over a period of 3 months. Enumeration of L. acidophilus by selective methods was verified by phenotypic identification of representative isolates. The total lactic acid bacteria (LAB) population ranged between 10(8) and 10(10) colony-forming units per gram of faeces over the 3 months period. L. acidophilus contributed on average a relatively constant figure of 10% to the total LAB population.

Animals↗

PubMed2002

Structural and functional analysis of the S-layer protein crystallisation domain of Lactobacillus acidophilus ATCC 4356: evidence for protein-protein interaction of two subdomains.

The structure of the crystallisation domain, SAN, of the S(A)-protein of Lactobacillus acidophilus ATCC 4356 was analysed by insertion and deletion mutagenesis, and by proteolytic treatment. Mutant S(A)-protein synthesised in Escherichia coli with 7-13 amino acid insertions near the N terminus or within regions of sequence variation in SAN (amino acid position 7, 45, 114, 125, 193), or in the cell wall-binding domain (position 345) could form crystalline sheets, whereas insertions in conserved regions or in regions with predicted secondary structure elements (positions 30, 67, 88 and 156) destroyed this capacity. FACscan analysis of L.acidophilus synthesising three crystallising and one non-crystallising S(A)-protein c-myc (19 amino acid residues) insertion mutant was performed with c-myc antibodies. Fluorescence was most pronounced for insertions at positions 125 and 156, less for position 45 and severely reduced for position 7. By cytometric flow sorting a transformant harbouring the mutant S(A)-protein gene (position 125) was isolated that showed an increased fluorescense signal. Immunofluorescence microscopy suggested that the transformant synthesized mutant S(A)-protein only. PCR analysis of the transformant grown in the absence of selection pressure indicated that the mutant allele was stably integrated in the chromosome. Proteolytic treatment of S(A)-protein indicated that only sites near the middle of SAN are susceptible, although potential cleavage sites are present through the entire molecule. Expression in E.coli of DNA sequences encoding the two halves of SAN yielded peptides that could oligomerize. Our results indicate that SAN consists of a approximately 12kDa N and a approximately 18kDa C-terminal subdomain linked by a surface exposed loop. The capacity of S(A)-protein of L.acidophilus to present epitopes, up to approximately 19 amino acid residues in length, at the bacterial surface in a genetically stable form, makes the system, in principle, suitable for application as an oral delivery vehicle.

Alleles↗

PubMed2002

Fructooligosaccharides and Lactobacillus acidophilus modify bowel function and protein catabolites excreted by healthy humans.

The objective of this experiment was to determine whether supplementation with fructooligosaccharides (FOS) and (or) Lactobacillus acidophilus (LAC) affected bowel function and fermentative end-product concentrations in feces of healthy humans. Subjects (n = 68) were enrolled in a randomized, double-blind, placebo-controlled, parallel study design. After a 4-wk baseline period, subjects consumed one of the following treatments twice daily for 4 wk: 1) 3 g sucrose + 80 mg cornstarch; 2) 3 g FOS + 80 mg cornstarch; 3) 3 g sucrose + 1 x 10(9) colony-forming units (cfu) LAC; or 4) 3 g FOS + 1 x 10(9) cfu LAC. Subjects completed 7-d bowel function forms and 3-d dietary records before collection of fresh stool samples at wk 4, 6 and 8. Statistical analyses were performed on differences from baseline using the General Linear Models procedure of SAS. Fructooligosaccharides decreased fecal ammonia (P = 0.07) and isovalerate (P = 0.12) concentrations at wk 6. At wk 8, FOS tended (P = 0.11) to increase fecal putrescine concentrations. Lactobacillus decreased fecal organic matter percentage at wk 6 (P < 0.05) and 8 (P = 0.07). At wk 6 and 8, LAC increased (P < 0.05) fecal 2-methylindole, total indole, and total indole and phenol concentrations. At wk 8, LAC decreased fecal agmatine (P = 0.08) and phenylethylamine (P < 0.05) concentrations. In conclusion, FOS and LAC modified several metabolites associated with gut health, with FOS tending to be beneficial (decreased fecal protein catabolites) and LAC being negative (increased fecal protein catabolites).

Adult↗

PubMed2005

Fermentation pH and temperature influence the cryotolerance of Lactobacillus acidophilus RD758.

The effects of 3 fermentation temperatures (30, 37, and 42 degrees C) and 3 fermentation pH (4.5, 5, and 6) on the cryotolerance of Lactobacillus acidophilus RD758 were studied in relation to their fatty acid composition. Cryotolerance was defined as the ability of the cells to recover their acidification activity after freezing and frozen storage at -20 degrees C. Better cryotolerance was obtained in cells grown at 30 degrees C or at pH 5; these cells showed no loss in acidification activity during freezing and a low rate of loss in acidification activity during frozen storage. On the other hand, cells grown at 42 degrees C or at pH 4.5 displayed poor cryotolerance. The membrane fatty acid composition was analyzed and related to the cryotolerance using principal component analysis. The improved cryotolerance observed during the freezing step was associated with a high ratio of unsaturated to saturated fatty acids, a low C18:0 content, and high C16:0 and cyclic C19:0 relative concentrations. High resistance during frozen storage was related to a high cycC19:0 concentration. Finally, the low cryotolerance observed after fermentation at pH 4.5 was explained by a low C18:2 content.

Cell Membrane↗

PubMed2005

[Study on effect of Lactobacillus acidophilus MG2-1 on serum lipid metabolism in rats].

Wistar rats were fed with a high lipid diet supplemented with living or thermal death bacteria of Lactobacillus acidophilus MG2-1 which was isolated from koumiss in Mongolia and was of good ability of acid tolerance and decreasing the level of cholesterol in vitro. The effect of Lb. acidophilus MG2-1 on the metabolism of serum cholesterol was discussed. It was showed that it was on the 14th day of experiment that the inhibiting effects of the increase of serum cholesterol level of rat groups fed with living bacteria and heat-killed bacteria was significantly (p > 0.05) and very significantly (p < 0.01) higher than that of the high lipid diet group respectively; at the same time, the level of serum HDL-C of the thermal death bacteria group was significantly higher than that of the high lipid diet group (p < 0.05), also arteriosclerosis index of wistar rats in experimental group is significantly lower than that of the high lipid diet group (p < 0.01). The total bile acid level of the thermal death bacteria group in fecal is significantly higher than that of the high lipid diet group (p < 0.05). It is suggested that the increase of serum cholesterol level in rats can be inhibited and arteriosclerosis can also be prevented by this strain. During the period of tests, the effect of the strain on serum lipid in rats weaken with the time going, while the dose of bacteria fed was not changed.

Animals↗

PubMed1990

Factors to consider when selecting a culture of Lactobacillus acidophilus as a dietary adjunct to produce a hypocholesterolemic effect in humans.

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.

Bacteriocins↗