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PubMedDate not supplied

[Ultrastructural changes in Shigella flexneri cells during interaction with bacteriocinogenic Lactobacillus acidophilus].

Results of electron-microscopic examination of Shigella flexneri cells, subjected to influence the bacteriocin-producing Lactobacillus acidophilus bacteria are presented. The response of shigellae to bacteriocinogenic lactobacilli was shown both on cellular and population levels. On population level the correlation of various morphological types of shigella cells with increase of involution, lysing and resting forms is revealed. At a cellular level the specific ultrastructural changes of shigella evidencing the significant destructive processes of the cells were revealed. In one case destabilization of shigella cellular wall was observed, that was manifested in expansion of periplasmic spaces and appearence of specific involution forms of the cells. In other cases, changes in the ultrastructural organization of shigella nucleoid were found out, manifested in disappearance of thin-fibrillar DNA and formation of electronic-dense globular structures of the cells.

Antibiosis↗

PubMed1992

Effect of Bifidobacterium bifidum and Lactobacillus acidophilus on gut mucosa and peripheral blood B lymphocytes.

In 15 elderly individuals lyophilized Bifidobacterium bifidum (BB) and Lactobacillus acidophilus (LA) (Infloran) were administered in capsules (two capsules 4 times per day) for 28 days, while in 10 elderly controls placebo were given the same posology and for an equal period of time. The effects of this treatment on the immune system both at the periphery or the intestinal level were investigated. Results show that BB and LA significantly reduced the colonic inflammatory infiltration, without altering T, B and Leu7 + cell percentage. At the same time, a significant increase of B cell frequency in the peripheral blood was noted, in comparison to controls. The overall results suggest that the regular administration of BB and LA leads to a modulation of the immunological and inflammatory response in elderly subjects.

Aged↗

PubMed1997

The human Lactobacillus acidophilus strain LA1 secretes a nonbacteriocin antibacterial substance(s) active in vitro and in vivo.

The adhering human Lactobacillus acidophilus strain LA1 inhibits the cell association and cell invasion of enteropathogens in cultured human intestinal Caco-2 cells (M. F. Bernet, D. Brassard, J. R. Neeser, and A. L. Servin, Gut 35:483-489, 1994). Here, we demonstrate that strain LA1 developed its antibacterial activity in conventional or germ-free mouse models orally infected by Salmonella typhimurium. We present evidence that the spent culture supernatant of strain LA1 (LA1-SCS) contained antibacterial components active against S. typhimurium infecting the cultured human intestinal Caco-2 cells. The LA1-SCS antibacterial activity was observed in vitro against a wide range of gram-negative and gram-positive pathogens, such as Staphylococcus aureus, Listeria monocytogenes, S. typhimurium, Shigella flexneri, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterobacter cloacae. By contrast, no activity was observed against species of the normal gut flora, such as lactobacilli and bifidobacteria. The LA1-SCS antibacterial activity was insensitive to proteases and independent of lactic acid production.

Animals↗

PubMed2003

Prophylactic feeding of Lactobacillus acidophilus NCFM to mice attenuates overt colonic hyperplasia.

The objective of this project was to determine if the probiotic Lactobacillus acidophilus NCFM would protect mice from developing transmissible murine colonic hyperplasia (TMCH) caused by Citrobacter rodentium. Our hypothesis was that the oral administration of L. acidophilus NCFM to mice would mitigate colonic hyperplasia and modulate the host immune response. A concurrent administration (CA) study was performed by feeding mice phosphate-buffered saline (PBS), C. rodentium only, L. acidophilus NCFM only, or C. rodentium and NCFM concurrently on the same day. The mice in the CA study were not protected by the probiotic, since their mean colon sample weights (0.109 g) were significantly higher than those of the PBS controls (0.0774 g), and the hematoxylin and eosin-stained samples showed histological changes typically associated with TMCH. A prophylactic feeding (PF) study was performed by orally feeding mice PBS or NCFM once daily for 20 consecutive days; in addition, on day 7, mice were challenged with either PBS or C. rodentium. Mice in the PF study were protected when they consumed the probiotic prior to the pathogen challenge, since their mean colon sample weights (0.0812 g) were not significantly higher than those of the controls (0.0753 g). The hematoxylin and eosin-stained samples appeared similar to the control samples, and the intestinal interleukin (IL)-15 and gamma interferon (IFN-gamma) mRNA levels were reduced. L. acidophilus NCFM did attenuate overt colonic hyperplasia when fed to mice prior to challenge with C. rodentium. The mouse model used in this study enabled us to investigate the efficacy of the L. acidophilus NCFM in preventing gastrointestinal disease and is a valid model for future probiotic research.

Administration, Oral↗

PubMed2001

[Effects of para-aminobenzoic acid (PABA) on growth of Lactobacillus acidophilus].

OBJECTIVE: The aim of this study is to examine effects of para-aminobenzoic acid (PABA) on the growth of Lactobacillus acidophilus (L. acidophilus). METHODS: Different concentrations of PABA (10(-10)-10(-3) g/L) were separately transferred to the modified Carlsson medium. L. acidophilus (ATCC4356) grew in these Carlsson media. All cultures were incubated at 37 degrees C anaerobically in atmosphere of 80% of nitrogen, 10% of hydrogen, and 10% of carbon dioxide for 48 hours. Absorbance values (lambda = 540 nm) of bacterial suspensions were measured using a spectrometer (UV-1601). Colony forming units (CFU) were obtained by growing L. acidophilus in Carlsson media with different concentration of PABA (10(-10)-10(-3) g/L). RESULTS: Different concentrations of PABA (10(-10)-10(-4) g/L) had different stimulating effects on the growth of L. acidophilus (P < 0.05). But stimulating effects declined, when PABA concentration was 10(-5) g/L, and when the concentration of PABA reached 10(-3) g/L, the stimulating effect disappeared. CONCLUSION: This study indicates PABA stimulates the growth of L. acidophilus, and PABA can promote growth of L. acidophilus.

4-Aminobenzoic Acid↗

PubMed1997

In vitro lactose fermentation by human colonic bacteria is modified by Lactobacillus acidophilus supplementation.

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

Adult↗

PubMed1984

Isolation and characterization of an aminopeptidase from Lactobacillus acidophilus R-26.

An intracellular aminopeptidase (alpha-aminoacyl-peptide hydrolase (cytosol), EC 3.4.11.1) isolated from cell extracts of Lactobacillus acidophilus R-26 was purified 634-fold to homogeneity. This enzyme, which was responsible for all of the N-terminal exopeptidase and amidase activities observed in crude extracts, had no detectable endopeptidase or esterase activity. Although a broad range of L-amino acid peptide, amide and p-nitroanilide derivatives possessing free alpha-amino termini are attacked, the enzyme favored substrates with hydrophobic N-terminal R groups. The native enzyme, which was found to be a tetramer of molecular weight 156000, contained 4 mol of tightly bound Zn2+. The catalytically inactive native zinc metalloenzyme was capable of being activated by either Zn2+, Co2+, Ni2+ or Mn2+. The shape of the log Vmax versus pH plot indicates that two active-center ionizable groups (pKES1 = 5.80; pKES2 = 8.00) may be involved in catalysis. Methylene-blue-sensitized photooxidation of the enzyme resulted in the complete loss of activity, while L-leucine, a competitive inhibitor, partially protected against this inactivation. Amino-acid analysis indicated that this photooxidative loss of activity corresponds to the modification of one histidine residue per monomer of protein.

Amino Acids↗

PubMed2005

Influence of fermentation medium composition on physicochemical surface properties of Lactobacillus acidophilus.

The effect of the simple and complex basic components of a fermentation medium on the surface properties of Lactobacillus acidophilus NCC2628 is studied by physicochemical methods, such as electrophoresis, interfacial adhesion, and X-ray photonelectron spectroscopy, and by transmission electron microscopy. Starting from an optimized complete medium, the effect of carbohydrates, peptones, and yeast extracts on the physicochemical properties of the cell wall is systematically investigated by consecutively omitting one of the principal components from the fermentation medium at the time. The physicochemical properties and structure of the bacterial cell wall remain largely unchanged if the carbohydrate content of the fermentation medium is strongly reduced, although the concentration of surface proteins increases slightly. Both peptone and yeast extract have a considerable influence on the bacterial cell wall, as witnessed by changes in surface charge, hydrophobicity, and the nitrogen-to-carbon ratio. Both zeta potential and the cell wall hydrophobicity show a positive correlation with the nitrogen-to-carbon ratio of the bacterial surfaces, indicative of the important role of surface proteins in the overall surface physical chemistry. The hydrophobicity of the cell wall, which is low for the cultures grown in the complete medium and in the absence of carbohydrates, becomes fairly high for the cultures grown in the medium without peptones and the medium without yeast extract. UV spectrophotometry and sodium dodecyl sulfate-polyacrylamide gel electrophoresis combined with liquid chromatography-tandem mass spectrometry are used to analyze the effect of medium composition on LiCl-extractable cell wall proteins, confirming the major change in protein composition of the cell wall for the culture fermented in the medium without peptones. In particular, it is found that expression of the S-layer protein is dependent on the protein source of the fermentation medium.

Bacterial Adhesion↗

PubMed1975

Detection of Lactobacillus acidophilus in feces of humans, pigs, and chickens.

Lactobacilli in fecal material from humans, pigs, and chickens were enumerated on lactobacillus selective agar (LBS). In all samples, higher numbers of lac-tobacilli were detected when plates were incubated in a system flushed with CO2 rather than in air. Much higher numbers of bacteria from human feces were detected when the LBS agar plates were incubated anaerobically in a hydrogen-carbon dioxide atmosphere (GasPak) than when incubated in CO2. The bacteria from human feces isolated on LBS agar incubated anaerobically were predominately bifidobacteria. Cultures from all three sources isolated on LBS agar incubated under CO2 were lactobacilli, including Lactobacillus acidophilus. Differences were observed in biochemical characteristics of some of the L. acidophilus isolated from all three sources. Guanine plus cytosine base ratios of deoxyribonucleic acid isolated from L. acidophilus cultures from humans were lower, in most cases, than those from pigs and chickens.

Agar↗

PubMed1992

Mouse intravaginal infection with Trichomonas vaginalis and role of Lactobacillus acidophilus in sustaining infection.

Recent work with a mouse model of Trichomonas vaginalis infection indicated that only 25% of mice harbor Lactobacillus spp. and that T. vaginalis infection rates fall rapidly after 7 days postinfection. In women infected with T. vaginalis, there is a disruption of the Lactobacillus population, which usually predominates. In an attempt to establish a better mouse intravaginal infection that resembles human disease, we established Lactobacillus acidophilus in estrogenized BALB/c mice. T. vaginalis was then inoculated intravaginally into mice previously infected with L. acidophilus and into mice in an untreated group. From 52 mice, 50-microliters vaginal washes were collected, cultured, and examined daily for live trichomonads after inoculation. Although initial infectivity in the two groups was comparable (79 to 83%), L. acidophilus-infected mice showed greater duration of infection. At day 24 postinfection, 69% of L. acidophilus-infected mice were still infected with T. vaginalis compared with only 11% of untreated mice (P = 0.002). The addition of L. acidophilus did not significantly alter the resident mouse vaginal flora. By the addition of L. acidophilus, the mouse will be valuable for studying factors involved in T. vaginalis infectivity and pathogenicity.

Animals↗

PubMed2003

Effect of spermicides on Lactobacillus acidophilus in vitro-nonoxynol-9 vs. Sapindus saponins.

Saponins extracted from the fruit pericarp of Sapindus mukorosii were tested for their bactericidal/bacteriostatic property against Lactobacillus acidophilus. Nonoxynol-9 was used as a reference compound for the comparison of activity. Lactobacillus colonies were grown on specific medium (Rogosa SL agar) containing different concentrations of saponins and nonoxynol-9 in an atmosphere of 5% CO2/95% air at 37 degrees C for 72 h. The number and size of colonies were recorded at the end of the experiment and compared with controls. Results indicated that nearly 90% of Lactobacillus colonies with minor reduction in size thrived at 0.05% concentration of saponins whereas only 18% of colonies with approximately 75% reduction in size grew in dishes containing 0.05% nonoxynol-9. At higher concentrations of saponins, there was a gradual, dose-dependent reduction in the number and size of colonies and at 2.5% concentration there was an approximately 55% reduction in the number and 60% reduction in the size of surviving colonies. No lactobacillus colonies, however, grew in dishes containing 0.1% and higher concentrations of nonoxynol-9. The studies indicate that Sapindus saponins as compared to nonoxynol-9 are far less toxic to lactobacillus species and therefore saponins containing spermicidal preparations are likely to be more vaginal-friendly than equivalent nonoxynol-9 preparations.

In Vitro Techniques↗

PubMedDate not supplied

Effect of lactose and Lactobacillus acidophilus on the colonization of Salmonella enteritidis in chicks concurrently infected with Eimeria tenella.

The effect of dietary lactose and Lactobacillus acidophilus on the colonization of Salmonella enteritidis (phage type 4) in newly hatched leghorn chicks concurrently infected with Eimeria tenella was studied. There were six groups of birds in each of two replicate trials: uninfected controls, birds infected with S. enteritidis, birds infected with S. enteritidis and E. tenella, birds infected with S. enteritidis and E. tenella that were fed with dietary lactose (5%), birds infected with S. enteritidis and E. tenella that were provided with L. acidophilus, and birds infected with S. enteritidis and E. tenella that were fed both L. acidophilus and dietary lactose (5%). Chickens were necropsied at 2, 5, and 8 days after S. enteritidis inoculation for bacteriological examination. The cecal population of S. enteritidis was significantly increased by infection with E. tenella. Lactose alone and the combination of lactose and L. acidophilus significantly reduced the population of S. enteritidis in the ceca of birds infected with E. tenella (P < 0.05), but the combination was more effective than lactose alone (P < 0.05). Adding anaerobic culture of L. acidophilus alone did not significantly decrease the population of S. enteritidis in the ceca. No significant reduction of colonization of S. enteritidis in the liver and spleen of birds with coccidiosis was observed.

Animals↗

PubMed1996

Construction of an integrative food-grade cloning vector for Lactobacillus acidophilus.

An integrative cloning vector was constructed using a randomly cloned HindIII-digested chromosomal fragment from Lactobacillus acidophilus ADH inserted into an Escherichia coli vector, pBluescript II SK+. Southern hybridization studies demonstrated homology of the inserted fragment with one other L. acidophilus strain and one Bifidobacterium strain. Identification of a SauI site located near the middle of the 1.9-kb ADH chromosomal fragment made it possible to clone the Lactobacillus bulgaricus beta-galactosidase (EC 3.2.1.23) gene into this vector. The vector was unable to replicate in the homologous host, L. acidophilus ADH, following electroporation. The chromosomal fragment allowed the integration of the beta-galactosidase gene (beta gal) into the host chromosome via homologous recombination. The size of the two flanking L. acidophilus ADH chromosomal fragments, approximately 0.95 kb each, was sufficient to allow the double cross-over to take place. Southern hybridization demonstrated that only L. acidophilus and L. bulgaricus DNA had been integrated into the chromosome of the host strain. The beta-galactosidase activity of the transformant was increased approximately 200-fold when compared to the enzyme activity of the wild-type strain. The beta gal gene remained stable in the transformant strain after 30 transfers in growth media without selection pressure. This first-generation integrative cloning vector is constructed solely of DNA from organisms consumed by humans and could be considered a food-grade vector system.

Bacterial Proteins↗

PubMed1984

Colonization of a human intestine by four different genotypes of Lactobacillus acidophilus.

To understand the effect on a human host suffering from intestinal disorders we supplied non fat milk cultures of Lactobacillus acidophilus for 25 days. The picture of the faeces bacterial count was completely different before and after treatment and we noticed increases in lactobacilli, bifidobacteria and coliforms while the clostridia decreased. The lactobacilli treatment solved the diarrohea problem. Of the four genetic lines of L. acidophilus supplied only D179, isolated from calf faeces, and ATCC 4356 of human origin were found able to colonize the intestine of the little girl, while 255S isolated from swine and D328 isolated from calf faeces, did not find favourable growth conditions.

Animals↗

PubMed1982

In vivo inhibitory effects of Lactobacillus acidophilus against pathogenic Escherichia coli in gnotobiotic chicks.

Chicks were hatched germfree in gnotobiotic isolators to determine the inhibitory effects of Lactobacillus acidophilus towards pathogeneic Escherichia coli in vivo. Twelve trials were conducted in two flexible film isolators utilizing a total of 221 chicks. One treatment consisted of inoculating 2-day-old chicks with L. acidophilus, then challenging with pathogenic E. coli with subsequent dosing with L. acidophilus. The other treatment consisted of challenging with the E. coli at 2 days of age, then subsequently dosing with L. acidophilus. Statistical analysis of the data showed initial dosing with L. acidophilus prevented excessive mortality when chicks were challenged with E. coli. Also, continued dosing with L. acidophilus lowered the pH in the crop, cecum, and rectum whether chicks were initially given L. acidophilus or E. coli. This strain of L. acidophilus was capable of competing with E. coli in the gut of gnotobiotic chicks.

Animals↗

PubMed2005

Effect of culture conditions on production of butter flavor compounds by Pediococcus pentosaceus and Lactobacillus acidophilus in semisolid maize-based cultures.

Two series of 120 h mixed cultures of Pediococcus pentosaceus MITJ-10 and Lactobacillus acidophilus Hansen 1748 were grown in semisolid maize-based media, applying an orthogonal factorial design in order to establish the most adequate parameters to get compounds related to butter-like flavor. Conditions of maize pre-treatment established in the first series were hot lime-treatment for 20 min, grinding and sieving to 0.0165 in., partial defatting and cooking for 25 min. While the culture conditions established for the second series were the addition of yeast extract (0.2% w/w), and culture starting with 2x10(6) CFU g(-1) and a ratio of P. pentosaceus and L. acidophilus, 3:1. The fermentation profile was studied in a last culture. Lactic acid bacteria (LAB) prevailed over the native microorganisms, with a specific growth rate of 0.47 h(-1). Diacetyl production correlated (r2=0.9972) with the 12 h exponential growth phase of LAB. The concentration of diacetyl at that time was 779.56 mg kg(-1). The contents of lactic acid and volatile fatty acids were low at 12 h, 665 and 1312 mg kg(-1), respectively. During the long stationary phase, they increased up to 4800 and 1886 mg kg(-1), respectively. This procedure might be useful to prepare naturally aromatized raw materials for the food industry.

Bacteriological Techniques↗

PubMed1996

Deoxycytidine kinase and deoxyguanosine kinase of Lactobacillus acidophilus R-26 are colinear products of a single gene.

Three of the four deoxynucleoside kinases required for growth of Lactobacillus acidophilus R-26 exist as heterodimeric pairs specific for deoxyadenosine (dAK) and deoxycytidine (dCK) or dAK and deoxyguanosine (dGK). However, only two tandem genes, dak/dgk, are found, and are expressed only as dAK/dGK in transformed Escherichia coli. Sequencing peptides spanning 63% of the native dCK subunit revealed a sequence identical to that deduced from dgk (beginning MTVIVL...), except that dCK lacks residues 2 and 3 (dCK is M..IVL; dGK is .TVIVL). Also, mass spectrometry indicates that native dCK and dGK subunits are identical in mass adjusted for the first three residues. Furthermore, the native enzymes have identical isoelectric pH values, indicating an equal number of charged residues. To enable E. coli to express peptide having the native dCK sequence, codons 2 and 3 were deleted from the dgk portion of the tandem genes, resulting in expression of protein having the specificities and regulatory properties of native dAK/dCK, including heterotropic stimulation of dAK activity by deoxycytidine or dCTP (not deoxyguanosine or dGTP) and end-product inhibition of the respective activities by dATP and dCTP. Subcloning normal and mutant dgk yielded homodimeric dGK and dCK, respectively. The dCK homodimer strongly resembles human dCK, with a low K(m) for deoxycytidine, the ability to phosphorylate deoxyadenosine and deoxyguanosine at much higher K(m) values, and end-product inhibition by dCTP. Thus two distinct and specific enzymes evidently are derived from a single Lactobacillus gene. The mechanism by which this occurs in vivo has yet to be elucidated.

Amino Acid Sequence↗

PubMed1993

S-layer protein of Lactobacillus acidophilus ATCC 4356: purification, expression in Escherichia coli, and nucleotide sequence of the corresponding gene.

The cell surfaces of several Lactobacillus species are covered by a regular layer composed of a single species of protein, the S-protein. The 43-kDa S-protein of the neotype strain Lactobacillus acidophilus ATCC 4356, which originated from the pharynx of a human, was purified. Antibodies generated against purified S-protein were used to screen a lambda library containing chromosomal L. acidophilus ATCC 4356 DNA. Several phages showing expression of this S-protein in Escherichia coli were isolated. A 4.0-kb DNA fragment of one of those phages hybridized to a probe derived from an internal tryptic fragment of the S-protein. The slpA gene, coding for the surface layer protein, was located entirely on the 4.0-kb fragment as shown by deletion analysis. The nucleotide sequence of the slpA gene was determined and appeared to encode a protein of 444 amino acids. The first 24 amino acids resembled a putative secretion signal, giving rise to a mature S-protein of 420 amino acids (44.2 kDa). The predicted isoelectric point of 9.4 is remarkably high for an S-protein but is in agreement with the data obtained during purification. The expression of the entire S-protein or of large, C-terminally truncated S-proteins is unstable in E. coli.

Amino Acid Sequence↗