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PubMed1989

Detection of lactobacilli and their interaction with clostridia in human gastrointestinal tracts and in vitro.

Culture counts of aerobic lactobacilli in the feces of vegetarians ([8.1 +/- 0.7] of log10 bacteria per gram dry weight) were higher than those of meat consumers ([5.2 +/- 0.1] of log10 bacteria per gram dry weight). Co-culture of Lactobacillus acidophilus and Clostridium perfringens in various media revealed that an interaction between these two species. The pH was the most important factor controlling their relative growth, which might explain the relative abundance of lactobacilli in feces of men and animals on vegetarian diets. Lactobacilli but not clostridia were detected in feces of newborn infants. These findings are discussed in relation to health.

Clostridium perfringens↗
PubMed1989

[Mechanism of antagonistic activity of lactobacilli].

Different species of lactobacilli, when grown together with salmonellae and shigellae, have been found to inhibit their growth and proliferation. The supernatants of the culture fluids of 8 species of lactobacilli have been shown to contain natural metabolites, other than lactic acid, with a wide spectrum of antibacterial activity with regard to different opportunistic aerobic and anaerobic microorganisms. The relationship between the antagonistic activity and the presence of plasmid DNA in a number of the most active antagonistic lactobacilli is discussed.

Antibiosis↗
PubMed1989

Results with the caries activity test "Cariostat" compared to prevalence of mutans streptococci and lactobacilli.

The colorimetric test, Cariostat (Sankin, Japan), for measuring the caries activity, based on the presence of acidogenic microorganisms, was evaluated. The results were compared with the prevalence of mutans streptococci and lactobacilli in the samples. Pure cultures of S. mutans and lactobacilli were inoculated into the test medium. A maximum color change from blue to yellow was not obtained not even when large numbers of bacteria were used. Samples of stimulated saliva and plaque samples from people with different salivary levels of mutans streptococci and lactobacilli were inoculated into the test medium. Samples with very low or very high numbers of cariogenic bacteria were found in all score groups indicating that the Cariostat test did not satisfactorily differentiate samples with low or high numbers of microorganisms associated with dental caries.

Adolescent↗
PubMed1987

Identification of vaginal lactobacilli from asymptomatic women.

In the present work, carried out by means of phenotypic and genotypic tests, it has been demonstrated that none of the vaginal lactobacilli isolated from asymptomatic women were genetically close to L. acidophilus ATCC 4356. Strains of homofermentative lactobacilli were identified as Lactobacillus gasseri, L. jensenii and L. crispatus, while in the heterofermentative only one strain was classified as L. fermentum. Moreover a genetically homologous group of heterofermentative lactobacilli, that could represent a new species, were evidenced.

DNA, Bacterial↗
PubMed1982

A mechanism of association of lactobacilli with the rat stomach epithelium.

The stomach wall of the rat is colonised by a dominant lactobacilli flora. The bacteria are localised mainly on the squamous epithelium (Table 1). They adhere tightly, covering the whole surface of the squamous epithelium (Fig. 1). On the secreting epithelium yeasts and bacteria were found only in connection with mucus (Fig. 2). In the present paper a mechanism of adhesion will be discussed. Piliform appendages (PA) were investigated with the aid of electron microscopy between the bacteria and the top cell layer of the epithelium and between the bacterial cells themselves (Fig. 3 and 4). They contain, following indications with scanning and transmission electron microscopy, material from the thin capsulae of acidic mucopolysaccharides, reported by Savage. Lactobacilli isolated from the squamous epithelium and cultivated in vitro are connected by the same piliform appendages. It seems, that the piliform appendages have an affinity to special receptor sites of the bacterial cell wall and also of the gastric epithelium. Lactobacilli situated on the secreting epithelium show piliform appendages, too, but they don't have a tight connection with the epithelial cells, only with the mucus.

Adhesiveness↗
PubMed1983

Exogenous lactobacilli fed to man - their fate and ability to prevent diarrheal disease.

Clinical and microbiologic studies were conducted to evaluate the capability of exogenous lactobacilli to implant in the upper small intestine, the ability of exogenous lactobacilli to prevent enterotoxigenic Escherichia coli (ETEC) diarrhea, and the effect of lactobacillus therapy in reduction of diarrhea due to neomycin. Microbiologic studies of jejunal aspirates indicated that orally ingested Lactobacillus acidophilus and L. bulgaricus in LactinexR and L. acidophilus in Infloran BernaR survived passage through the stomach and remained viable in the proximal small bowel for three to six hours in most, not all, individuals. Challenge studies with ETEC revealed that despite the ability of lactobacilli in LactinexR to persist in the upper small intestine for several hours, the lactobacillus preparation did not prevent or alter the course of ETEC diarrhea in adults. Lactobacillus therapy with one lot of LactinexR reduced the volume and duration of neomycin-associated diarrhea, whereas another lot of LactinexR had no therapeutic effect. Thus, lot to lot variations in lactobacillus preparations may account for some conflicting results observed with lactobacillus therapy for intestinal disorders.

Adolescent↗
PubMed1982

[Adhesive and hemagglutinating properties of lactobacilli].

The study of the adhesive and hemagglutinating properties of the strains of different Lactobacillus species isolated from the human digestive tract and sour milk products were carried out. 49 strains of 9 Lactobacillus species were studied; of these, 10 strains had been isolated from saliva, 11 strains from feces, 7 strains from milk and 5 strains from sour cream. 11 collection strains and 2 strains used in the production of lactobacterin served as controls. Adhesion was studied in vitro on human red blood cells used as a model. Red blood cells used in the experiments had been taken from 23 donors aged 25-52 years. Lactobacilli were found to have certain inter and intraspecific differences in their adhesiveness. The adhesiveness of the lactobacilli isolated from human feces was considerably greater than that of the strains isolated from sour milk products and of the collection strains. Only the strains of lactobacilli with low adhesiveness possessed pronounced hemagglutinating properties.

Adhesiveness↗
PubMedDate not supplied

[The binding of lactobacilli with soluble proteins and lectins].

The capacity of lactobacilli for binding with mucin (M), fibronectin (FN) and Concanavalin A (Con A) has been studied. Most of 33 strains of 8 Lactobacillus species have been found to possess a sufficiently high level of adhesion to immobilized FN and Con A and a low level of adhesion to M. The presence of inverse correlation between the binding of lactobacilli with M and FN has been established. This study has shown that the capacity of lactobacilli for adhesion to some soluble proteins and lectins is an additional marker for their characterization and can be used for the targeted correction on the intestinal microflora.

Bacterial Adhesion↗
PubMed1976

Intestinal colonization with lactobacilli strains in neutropenic patients.

In order to protect granulopenic patients against infections by pathogens from their own digestive tract, large amounts of lactobacilli were given to 5 patients whose intestinal flora had been suppressed by oral antibiotics. In all these cases, lactobacilli failed to prevent spontaneous recolonization of the gastrointestinal tract by enteric bacteria. Six attempts of colonization were made; in spite of the importance of the inoculum administered orally, large numbers of lactobacilli were recovered from stools in only two cases.

Aged↗
PubMed1992

In vitro antibacterial activity of antiseptics against vaginal lactobacilli.

The results of investigations carried out to evaluate the inhibitory activity in vitro of seven vaginal antiseptic douche solutions against several strains of vaginal lactobacilli isolated from asymptomatic women are reported. Some of the products examined showed marked antibacterial activity even at high dilutions and for short exposure times. The post-antibiotic effect of two of these antiseptics on vaginal lactobacilli was also evaluated. The results of these investigations suggest that uncontrolled use of antiseptic products could cause changes in the normal vaginal flora.

Anti-Infective Agents, Local↗
PubMed1991

Sequential fermentation of pearl millet by yeasts and lactobacilli--effect on the antinutrients and in vitro digestibility.

Sequential culture fermentation by yeasts (S. diastaticus or S. cerevisiae) at 30 degrees C for 72 hr and then followed by lactobacilli fermentation (L. brevis or L. fermentum) at 30 degrees C for 72 h more resulted in a significant reduction in phytic acid and polyphenol content of pearl millet flour. Fermentation by S. diastaticus and L. brevis combination almost eliminated phytic acid from pearl millet flour. The combinations of S. diastaticus with both the lactobacilli reduced phytic acid more effectively than those of S. cerevisiae. The products fermented by S. cerevisiae and L. brevis and by S. diastaticus and L. brevis combinations had the highest protein and starch digestibility (in vitro).

Dietary Carbohydrates↗
PubMed1998

Detection of ferulic acid esterase production by Bacillus spp. and lactobacilli.

The production of feruloyl esterase activity by Bacillus spp. and lactobacilli can be detected in an agarplate assay. The assay involves the substitution of the main carbon source in specific agar with ethyl ferulate. A number of Bacillus spp., predominantly B. subtilis strains, were found to exhibit feruloyl esterase activity by this method. Of the examined lactobacilli, Lb. fermentum (NCFB 1751) showed the highest level of ferulic acid esterase activity. The enzyme was released from harvested cells by sonication and showed pH and temperature optima of 6.5 and 30 degrees C respectively.

Bacillus↗
PubMed2001

Evaluation of nitric oxide production by lactobacilli.

Six strains of Lactobacillus fermentum and Lactobacillus plantarum were investigated for nitric oxide (NO) production. First, the potential presence of NO synthase was examined. None of the strains of L. fermentum and L. plantarum examined produced NO from L-arginine under aerobic conditions. Interestingly, all L. fermentum strains expressed strong L-arginine deiminase activity. All L. fermentum strains produced NO in MRS broth, but the NO was found to be chemically derived from nitrite, which was produced by L. fermentum from nitrate present in the medium. Indeed all L. fermentum strains express nitrate reductase under anaerobic conditions. Moreover, one strain, L. fermentum LF1, had nitrate reductase activity under aerobic conditions. It was also found that L. fermentum strains JCM1173 and LF1 possessed ammonifying nitrite reductase. The latter strain also had denitrifying nitrite reductase activity at neutral pH under both anaerobic and aerobic conditions. The LF1 strain is thus capable of biochemically converting nitrate to NO. NO and nitrite produced from nitrate by lactobacilli may constitute a potential antimicrobial mechanism. studied in a rat acute liver injury model (Adawi et al. 1997). The results indicate that Lactobacillus plantarum DSM 9842 may possess NOS (Adawi et al. 1997). However, NO production from L-arginine has not been investigated in pure cultures of L. plantarum. According to the results of a 15N enrichment experiment, traces of (NO2-+NO3-)-N (total oxidised nitrogen: TON), which seemed to be formed by the resting cells of Lactobacillus fermentum IFO3956, appeared to be derived from L-arginine (Morita et al. 1997). Therefore, it was suggested that L. fermentum may possess a NOS. However, NO produced from L-arginine was not directly measured and a NOS inhibitor test was not performed by Morita et al. (1997). It is known that L-arginine deiminase (ADI) in bacteria may convert L-arginine to NH4+ (Cunin et al. 1986), which may be further oxidised to TON via nitrification by bacteria. Therefore, 15N enrichment experiments could not definitely conclude that L. fermentum possess NOS to convert L-arginine directly to NO. In this study, six Lactobacillus strains belonging to L. plantarum and L. fermentum were measured for NO production in MRS broth. The metabolism of nitrate and L-arginine by the Lactobacillus cell suspensions was also studied. The possibility that NO and nitrite production by lactobacilli may be a potential probiotic trait is also discussed.

Arginine↗
PubMed2002

Modulation of the cell-surface proteinase activity of thermophilic lactobacilli by the Peptide supply.

The proteolytic system of thermophilic lactobacilli is considered important for bacterial nutrition as well as for the formation of flavor and texture in fermented products. We investigated the influence of peptide content on the cell surface proteinase and intracellular aminopeptidase activities from seven thermophilic lactobacilli strains. The proteinase activities were remarkably reduced in cells grown in the peptide-rich medium MRS or in a chemically defined medium supplemented with Casitone compared with those found in a synthetic medium. The degree of inhibition observed was strain dependent. When proteinase activities were analyzed by their hydrolytic patterns of alpha- and beta-casein degradation, four types of P(III)-caseinolytic cleavage specificity were distinguished. Lactobacillus helveticus strains possessed aminopeptidase activities with broader specificity than those found in L. delbrueckii subsp. lactis strains. However, the aminopeptidase activities were not influenced by the peptide content of the medium.

Aminopeptidases↗
PubMed1998

On the iron requirement of lactobacilli grown in chemically defined medium.

The iron requirement of four strains of lactobacilli (L. acidophilus, L. delbrueckii subsp. bulgaricus, L. plantarum, and L. pentosus) was studied in a synthetic medium under aerobic or anaerobic conditions. Effects of iron salt and iron-chelated compounds were tested on bacterial growth in manganese-free or -supplemented media. No significant growth stimulation was observed in any condition. These results support the absolute manganese requirement for optimum growth of lactobacilli and the needless incorporation of iron in growth media.

Aerobiosis↗
PubMed2004

Effect of yeast inoculation rate on the metabolism of contaminating lactobacilli during fermentation of corn mash.

Two separate 4 (bacterial concentrations)x6 (yeast concentrations) full factorial experiments were conducted in an attempt to identify a novel approach to minimize the effects caused by bacterial contamination during industrial production of ethanol from corn. Lactobacillus plantarum and Lactobacillus paracasei, commonly occurring bacterial contaminants in ethanol plants, were used in separate fermentation experiments conducted in duplicate using an industrial strain of Saccharomyces cerevisiae, Allyeast Superstart. Bacterial concentrations were 0, 1x10(6), 1x10(7) and 1x10(8) cells/ml mash. Yeast concentrations were 0, 1x10(6), 1x10(7), 2x10(7), 3x10(7), and 4x10(7) cells/ml mash. An increased yeast inoculation rate of 3x10(7) cells/ml resulted in a greater than 80% decrease (P < 0.001) and a greater than 55% decrease (P < 0.001) in lactic acid production by L. plantarum and L. paracasei, respectively, when mash was infected with 1x10(8) lactobacilli/ml. No differences (P > 0.25) were observed in the final ethanol concentration produced by yeast at any of the inoculation rates studied, in the absence of lactobacilli. However, when the mash was infected with 1x10(7) or 1x10(8) lactobacilli/ml, a reduction of 0.7-0.9% v/v (P < 0.005) and a reduction of 0.4-0.6% v/v (P < 0.005) in the final ethanol produced was observed in mashes inoculated with 1x10(6) and 1x10(7) yeast cells/ml, respectively. At higher yeast inoculation rates of 3x10(7) or 4x10(7) cells/ml, no differences (P > 0.35) were observed in the final ethanol produced even when the mash was infected with 1x10(8) lactobacilli/ml. The increase in ethanol corresponded to the reduction in lactic acid production by lactobacilli. This suggests that using an inoculation rate of 3x10(7) yeast cells/ml reduces the growth and metabolism of contaminating lactic bacteria significantly, which results in reduced lactic acid production and a concomitant increase in ethanol production by yeast.

Equipment Contamination↗
PubMed1984

The effect of caries-preventive measures in mothers on dental caries and the oral presence of the bacteria Streptococcus mutans and lactobacilli in their children.

Seventy-seven first-time mothers were selected on the basis of high salivary counts of Strep. mutans [greater than 10(6) c.f.u. (colony forming units) per ml saliva]; 40 mothers were in the control group and 37 in the test group. Their infants were 3-8 months of age at the start of the study. A prophylactic programme for the test mothers, aiming at a reduction of Strep. mutans, was repeated at intervals of 2-4 months as and when necessary until their children were 3 years old. The test mothers as a group showed approx. 10-fold fewer Strep. mutans during the test period. At the age of 3 years, 70 per cent of the children in the control group carried Strep. mutans, compared with 41 per cent in the test group (p less than 0.01). Fifty-two per cent of the children who carried Strep. mutans had caries at this age, compared to 3 per cent of the children without this organism. The time when Strep. mutans was first detected in the children seemed to influence subsequent development of caries because 77 per cent of the children who carried Strep. mutans at the age of 15 months had caries at the age of 3 years. Approximately 40 per cent of the children in both the control and the test group had detectable lactobacilli in their saliva at 3 years. In general, the children in the control group had more lactobacilli.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Biochemical characterization of lactobacilli from dry fermented sausages.

The characterization of 254 strains of lactobacilli isolated from dry spontaneously fermented sausages from 15 different producers at two different stages of ripening time is reported. The species identified were Lactobacillus sake 55%, L. curvatus 26%, L. bavaricus 11% and L. plantarum 8%. The main criteria for the identification of isolates to species level were: production of lactic acid isomers, presence of mDpm acid in cell walls, deamination of arginine and fermentation of mannitol and melibiose. The composition of the populations of lactobacilli were the same for the two stages of ripening. The deamination of arginine was tested in aerobic and anaerobic cultures and in different media by checking the production of ammonia and detecting the production of citrulline. In 94% of strains tested both methods gave identical results. In two L. sake strains arginine catabolism was dependent on culture media; for two other L. sake strains the deamination of arginine only occurred when oxygen was scarce.

Animals↗