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PubMed1973

Effect of alcohol on serum folate level.

Alcohol was given orally and intravenously to normal and chronic alcoholic volunteers to study its effect on folate metabolism. Oral alcohol, given to nine subjects on a low folate diet, caused a greater fall in serum Lactobacillus casei folate levels than that seen in eight subjects on a low folate diet alone. This alcohol-induced fall in serum folate level occurred largely during the 1st day of the protocol. Although brief infusions of intravenous ethanol had no effect on serum folate level, a 13 h infusion caused a striking fall in serum folate level between the 8th and 10th h. When ethanol was stopped, the serum folate level returned rapidly to normal. Two chronic alcoholic subjects with different basal levels of serum folate were studied for several weeks on a low folate diet plus alcohol. The serum folate level fell promptly in each subject, rose when alcohol was temporarily stopped, and fell when alcohol was resumed. Folate-deficient megaloblastic anemia developed in 3 wk in the subject with initially marginal serum folate levels, but failed to develop in almost 7 wk in the subject with normal folate stores, as reflected by initially high serum folate levels. Thus, the alcohol-induced fall in serum folate level was apparently not a result of depletion of folate stores. In vitro experiments ruled out an assay artifact as an explanation for the alcohol-induced fall in serum L. casei folate level. It seems likely that alcohol interferes with the delivery of n-5-methyltetrahydrofolic acid from storage areas.

Acetaldehyde↗
PubMed1990

The F1-type ATPase in anaerobic Lactobacillus casei.

An ATPase from anaerobic Lactobacillus casei has been isolated and 100-times purified. The 400 kDa enzyme molecule was found to have a hexagonal structure 10 nm in diameter composed of at least six protein masses. SDS-electrophoresis reveals four or, under certain conditions, five types of subunit, of apparent molecular masses 57 (alpha), 55 (beta), 40 (gamma), 22 (delta) and 14 (epsilon) kDa with stoichiometry of 3 alpha, 3 beta, gamma, delta, epsilon. The following features resembling F1-ATPases from other sources were found to be inherent in the solubilized L. casei ATPase. (i) Detachment from the membrane desensitizes ATPase to low DCCD concentrations and sensitizes it to water-soluble carbodiimide. (ii) Soluble ATPase is inhibited by Nbf chloride and azide, is resistant to SH-modifiers and is activated by sulfite and octyl glucoside, the activating effect being much stronger than in the case of the membrane-bound ATPase. Substrate specificity of the enzyme is also similar to that of other factors F1. Divalent cations strongly activate the soluble enzyme when added at a concentration equal to that of ATP. An excess of Mn2+, Mg2+ or Co2+ inhibits ATPase activity of F1, whereas that of Ca2+ induces its further activation. No other F1-like ATPases are found in L. casei. It is concluded that this anaerobic bacterium possesses a typical F1-ATPase similar to those in mitochondria, chloroplasts, aerobic and photosynthetic eubacteria.

Catalysis↗
PubMed1977

Pteridines. 41. Synthesis and dihydrofolate reductase inhibitory activity of some cycloalka[g]pteridines.

A number of homologous 2,4-diaminocycloalka[g]pteridines varying in ring size from 5 to 15 were prepared by (a) condensation of aminomalononitrile tosylate with alpha-oximinocycloalkanones, deoxygenation of the resulting 2-amino-3-cyanocycloalka[b]pyrazine 1-oxides, and guanidine cyclization; (b) guanidine cyclization of the above pyrazine 1-oxides to give 2,4-diaminocycloalka[g]pteridine 8-oxides, followed by deoxygenation; or (c) condensation of 2,4,5,6-tetraaminopyrimidine with a cycloalka-1,2-dione (for the cyclohepta- and cycloocta[g]pteridines only). These compounds were examined for their activity as dihydrofolate reductase inhibitors against Lactobacillus casei, rat liver, L1210, and Trypanosoma cruzi. Activity was found to depend upon ring size, with the greatest activity exhibited by the cyclododeca derivatives 31.

Animals↗
PubMed2003

Effect of frequent consumption of a Lactobacillus casei-containing milk drink in Helicobacter pylori-colonized subjects.

BACKGROUND: Several studies have reported inhibitory effects of lactic acid bacteria on bacterial pathogens. AIM: To test whether a drink containing Lactobacillus casei strain Shirota inhibits Helicobacter pylori growth. METHODS: The in vitro growth inhibition of H. pylori was studied when L. casei was added to plates previously inoculated with H. pylori reference strain NCTC 11637. In an intervention study, 14 H. pylori-positive subjects were given Yakult drink (10(8) colony-forming units/mL L. casei) thrice daily during meals for 3 weeks. Six untreated H. pylori-positive subjects served as controls. H. pylori bacterial loads were determined using the 13C-urea breath test, which was performed before and 3 weeks after the start of L. casei supplementation. RESULTS: In vitro, L. casei inhibits H. pylori growth. This effect was stronger with L. casei grown in milk solution than in DeMan-Rogosa-Sharpe medium. No growth inhibition was shown with medium inoculated with lactic acid, Escherichia coli strain DH5alpha or uninoculated medium. Filtration of L. casei culture before incubation with H. pylori completely abolished the inhibitory effect. Urease activity decreased in nine of the 14 (64%) subjects with L. casei supplementation and in two of the six (33%) controls (P = 0.22). CONCLUSIONS: Viable L. casei are required for H. pylori growth inhibition. This does not result from changes in lactic acid concentration. In addition, a slight, but non-significant, trend towards a suppressive effect of L. casei on H. pylori in vivo may exist.

Adult↗
PubMed1977

Rate-limiting steps in folate metabolism by Lactobacillus casei.

Oxidation of 5-methyltetrahydrofolate to 5,10-methylenetetrahydrofolate was the rate-limiting step in 5-methyltetrahydrofolate metabolism by Lactobacillus casei. The limiting steps in the utilization of suboptimal levels of folate by L. casei were related to the ability of folates to function in purine and/or thymidylate biosynthesis. Folates with glutamate chains of up to at least seven residues were substrates for these biosynthetic enzymes, and comparisons of bacterial growth yields with transport rates for these folates indicated that the polyglutamates were more effective substrates in purine and thymidylate synthesis than the corresponding pteroylmonoglutamates. Lactobacillus casei contained low levels of a B12-independent, pteroylpolyglutamate-specific methionine synthetase. Its methylenetetrahydrofolate reductase also functioned more effectively with pteroylpolyglutamate substrates.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1985

Presence of Lactobacillus casei in saliva from children and adults using a new medium.

The aim of this study was to devise a medium for cultivation of L. casei and to compare the presence of L. casei in saliva from children and adults. The new medium was produced by omitting the sugars from Rogosa SL agar medium and supplementing this medium with melezitose. Although all tested strains of lactobacilli grew on the new medium, the facultatively homofermentative lactobacilli, L. casei and L. plantarum, could be identified by a typical colonial morphology. L. casei was the most common species of oral lactobacilli in saliva from children and made up a significantly higher proportion of the salivary lactobacillus flora in children than in adults.

Adolescent↗
PubMed2000

Generation of food-grade recombinant lactic acid bacterium strains by site-specific recombination.

The construction of a delivery and clearing system for the generation of food-grade recombinant lactic acid bacterium strains, based on the use of an integrase (Int) and a resolvo-invertase (beta-recombinase) and their respective target sites (attP-attB and six, respectively) is reported. The delivery system contains a heterologous replication origin and antibiotic resistance markers surrounded by two directly oriented six sites, a multiple cloning site where passenger DNA could be inserted (e.g., the cI gene of bacteriophage A2), the int gene, and the attP site of phage A2. The clearing system provides a plasmid-borne gene encoding beta-recombinase. The nonreplicative vector-borne delivery system was transformed into Lactobacillus casei ATCC 393 and, by site-specific recombination, integrated as a single copy in an orientation- and Int-dependent manner into the attB site present in the genome of the host strain. The transfer of the clearing system into this strain, with the subsequent expression of the beta-recombinase, led to site-specific DNA resolution of the non-food-grade DNA. These methods were validated by the construction of a stable food-grade L. casei ATCC 393-derived strain completely immune to phage A2 infection during milk fermentation.

Animals↗
PubMed2003

Influence of adjunct use and cheese microenvironment on nonstarter bacteria in reduced-fat cheddar-type cheese.

This study investigated population dynamics of starter, adjunct, and nonstarter lactic acid bacteria (NSLAB) in reduced-fat Cheddar and Colby cheese made with or without a Lactobacillus casei adjunct. Duplicate vats of cheese were manufactured and ripened at 7 degrees C. Bacterial populations were monitored periodically by plate counts and by DNA fingerprinting of cheese isolates with the random amplified polymorphic DNA technique. Isolates that displayed a unique DNA fingerprint were identified to the species level by partial nucleotide sequence analysis of the 16S rRNA gene. Nonstarter biota in both cheese types changed over time, but populations in the Colby cheese showed a greater degree of species heterogeneity. The addition of the L. casei adjunct to cheese milk at 10(4) cfu/ml did not completely suppress "wild" NSLAB populations, but it did appear to reduce nonstarter species and strain diversity in Colby and young Cheddar cheese. Nonetheless, nonstarter populations in all 6-mo-old cheeses were dominated by wild L. casei. Interestingly, the dominant strains of L. casei in each 6-mo-old cheese appeared to be affected more by adjunct treatment and not cheese variety.

Carbohydrate Metabolism↗
PubMed1983

Characterization of the DNA binding region recognized by dihydrofolate reductase from lactobacillus casei.

Two specific DNA binding sites for the enzyme dihydrofolate reductase from Lactobacillus casei have been located by means of an immunoprecipitation assay within a 2900-base pair L. casei DNA fragment containing the L. casei dihydrofolate reductase structural gene, which was previously cloned into pBR322. The inserted L. casei DNA was mapped using restriction endonucleases, and the location and orientation of the structural gene coding for L. casei dihydrofolate reductase were determined. The two specific binding sites map at the 5' end of the structural gene, approximately 100 base pairs upstream from the start of the coding region.

Binding Sites↗
PubMed2000

Bacterial supplementation in the irritable bowel syndrome. A randomised double-blind placebo-controlled crossover study.

BACKGROUND: Symptoms of at least a subgroup of patients with irritable bowel syndrome may be associated with an alteration in gut flora. Studies on bacterial based therapy have yielded mixed results. AIMS: To determine if oral administration of the probiotic Lactobacillus casei strain GG under randomized placebo controlled conditions improves symptoms in irritable bowel syndrome patients with bloating related symptoms. PATIENTS: A total of 25 patients with clinically confirmed irritable bowel syndrome (Rome criteria) were enrolled in the study. METHODS: This was a randomised double-blind placebo-controlled crossover trial. Lactobacillus GG was administered as enterocoated tablets constituting a daily dosage of 10(10) colony forming units. Symptoms were assessed by daily symptom diaries and periodic questionnaires. RESULTS: Twenty-four patients were randomised; 19 (80%) female, mean age 40 years (range 24-60), mean duration of symptoms 4.9 years (range 0.5-18). Nineteen (80%) patients completed the study. No significant differences were found between Lactobacillus casei strain GG and placebo mean symptom scores for pain, urgency or bloating. A trend was noted, however, for a reduction in the number of unformed bowel motions on Lactobacillus casei strain GG treatment for patients with diarrhoea. CONCLUSIONS: Lactobacillus casei strain GG alone did not significantly improve symptoms in this irritable bowel syndrome subgroup. A "diarrhoea predominant" subgroup may warrant further investigation.

Adult↗
PubMed1983

Folate analogues. 21. Synthesis and antifolate and antitumor activities of N10-(cyanomethyl)-5,8-dideazafolic acid.

A close analogue of the antileukemic agent 5,8-dideaza-N10 propargylfolic acid (2) was synthesized by replacing the propargyl moiety of 2 with a cyanomethyl group. This compound, N10-(cyanomethyl)-5,8-dideazafolic acid (3), was evaluated for its antifolate and antitumor activities in several biological test systems. Alkylation of diethyl N-(4-aminobenzoyl)-L-glutamate with bromoacetonitrile gave diethyl N-[4-[(cyanomethyl)amino]benzoyl]-L-glutamate (7). Reaction of 7 with 2 amino-6-(bromomethyl)-4-hydroxyquinazoline (9) in dimethylacetamide gave the corresponding diethyl ester 11, which was hydrolyzed to the target compound 3. The known antileukemic agent 2 was also synthesized for comparative studies by employing a modified procedure, which resulted in a better yield of this product. Both compounds 2 and 3 were evaluated for their antifolate activities by using two folate-requiring microorganisms, Streptococcus faecium and Lactobacillus casei. They were further evaluated as inhibitors of thymidylate synthase and dihydrofolate reductase derived from the above organisms, as well as for their antitumor activity by using selected tumor cells in culture. Compound 2 was found to be as equally potent as methotrexate (MTX) against S. faecium, and it was an excellent inhibitor of L. casei thymidylate synthase. The cyanomethyl analogue 3 was less active than 2 in all the test systems, except the inhibition of dihydrofolate reductase.

Antineoplastic Agents↗
PubMed1988

Synthesis and biological evaluation of poly-gamma-glutamyl metabolites of 10-deazaaminopterin and 10-ethyl-10-deazaaminopterin.

The chemical synthesis of a series of poly-gamma-glutamyl metabolites of the experimental anticancer drugs 10-deazaaminopterin (10-DAAM) and 10-ethyl-10-deazaaminopterin (10-EDAAM) has been carried out by the solid-phase procedure. The synthetic products were identical with the poly-gamma-glutamyl metabolites of radiolabeled 10-DAAM and 10-EDAAM produced by normal mouse tissues with regard to elution volume from [(diethylamino)ethyl]cellulose columns and susceptibility to hydrolysis by human plasma folylpolyglutamate hydrolase. Poly-gamma-glutamyl metabolites with a glutamate chain length of up to four glutamate residues were detected in the tissues. The antifolate activity was evaluated with methotrexate (MTX) sensitive and MTX-resistant strains of Lactobacillus casei and Streptococcus faecium. In general, inhibitory potency decreases with increasing Glu chain length. However there are two exceptions. Addition of one Glu residue to 10-DAAM enhances its potency for MTX-resistant L. casei and addition of one Glu residue to 10-EDAAM enhances its potency for the MTX-sensitive L. casei. As shown earlier for MTX polyglutamates, polyglutamylation greatly enhances the inhibitory potency of 10-DAAM and 10-EDAAM for L. casei thymidylate synthase. MTX polyglutamates are 15-30 times more inhibitory than the corresponding 10-DAAM derivatives and 30-60 times more inhibitory than the corresponding 10-EDAAM derivatives. Polyglutamylation of 10-DAAM had little influence on its ability to inhibit L. casei dihydrofolate reductase; however, with 10-EDAAM, addition of one or two Glu residues enhanced its inhibitory potency 2.3-fold.

Aminopterin↗
PubMed1999

Partial characterization and plasmid linkage of a non-proteinaceous antimicrobial compound in a Lactobacillus casei strain of vegetable origin.

Lactobacillus casei IMPC LC34 of vegetable origin produces a non-proteinaceous inhibitory compound with a broad spectrum of activity towards Gram-positive and Gram-negative bacteria, including pathogens. The active substance, mainly produced in the stationary phase of growth, is insensitive to proteolytic enzymes, lipase and catalase, and is stable at 121 degrees C for 30 min. The inhibitory activity was detected either at 8 degrees C or at 37 degrees C. The active compound does not contain glucidic groups, is inactivated by Na-metaperiodate, and its molecular mass is between 2000 and 5000 Da. Plasmid curing experiments showed that both antimicrobial compound immunity and production determinants were encoded by an 8.8 kbp plasmid. The effectiveness of the active agent was verified on ready-to-use vegetables, using either the Lact. casei strain or its culture supernatant fluid as inoculant, compared with cured clone. The application potential of the Lact. casei strain or its culture supernatant fluid for assuring the microbiological safety of ready-to-use vegetables is discussed.

Anti-Bacterial Agents↗
PubMed2006

Production of a heterologous nonheme catalase by Lactobacillus casei: an efficient tool for removal of H2O2 and protection of Lactobacillus bulgaricus from oxidative stress in milk.

Lactic acid bacteria (LAB) are generally sensitive to H2O2, a compound that they can paradoxically produce themselves, as is the case for Lactobacillus bulgaricus. Lactobacillus plantarum ATCC 14431 is one of the very few LAB strains able to degrade H2O2 through the action of a nonheme, manganese-dependent catalase (hereafter called MnKat). The MnKat gene was expressed in three catalase-deficient LAB species: L. bulgaricus ATCC 11842, Lactobacillus casei BL23, and Lactococcus lactis MG1363. While the protein could be detected in all heterologous hosts, enzyme activity was observed only in L. casei. This is probably due to the differences in the Mn contents of the cells, which are reportedly similar in L. plantarum and L. casei but at least 10- and 100-fold lower in Lactococcus lactis and L. bulgaricus, respectively. The expression of the MnKat gene in L. casei conferred enhanced oxidative stress resistance, as measured by an increase in the survival rate after exposure to H2O2, and improved long-term survival in aerated cultures. In mixtures of L. casei producing MnKat and L. bulgaricus, L. casei can eliminate H2O2 from the culture medium, thereby protecting both L. casei and L. bulgaricus from its deleterious effects.

Animals↗
PubMedDate not supplied

[Folacin determination in the blood by a fluorimetric method].

To determine the blood folacin a fluorometric method is proposed. This includes the following stage-wise operations: liberation of combined forms of folacin under the effect of enzymes contained in the blood investigated; quantification of tyrosine to make a correction for changed fluorescence intensity of this amino acid during oxilation of the solution; measurement of the fluorescence of the substances present in the solution before and after their oxidation with potassium permanganate and calculation of the folacin content. The fluorometric method enables it to greatly speed up the assay by comparison with the microbiological method of determination with the Lactobac. casei as a test-organism, the assay time being cut down from 4-5 days to 4-5 hours without prejudicing the accuracy of the determination.

Animals↗
PubMed2001

Optimisation of media and cultivation conditions for L(+)(S)-lactic acid production by Lactobacillus casei NRRL B-441.

Process variables and concentration of carbon in media were optimised for lactic acid production by Lactobacillus casei NRRL B-441. Lactic acid yield was inversely proportional to initial glucose concentration within the experimental area (80-160 g l(-1)). The highest lactic acid concentration in batch fermentation, 118.6 g l(-1), was obtained with 160 g 1(-1) glucose. The maximum volumetric productivity, 4.4 g 1(-1) h(-1) at 15 h, was achieved at an initial glucose concentration of 100 g l(-1). Similar lactic acid concentrations were reached with a fedbatch approach using growing cells, in which case the fermentation time was much shorter. Statistical experimental design and response surface methodology were used for optimising the process variables. The temperature and pH optima for lactic acid production were 35 degrees C, pH 6.3. Malt sprout extract supplemented with yeast extract (4 g l(-1)) appeared to be an economical alternative to yeast extract alone (22 g l(-1)) although the fermentation time was a little longer. The results demonstrated both the separation of the growth and lactic acid production phases and lactic acid production by non-growing cells without any nutrient supplements. Resting L. casei cells converted 120 g l(-1) glucose to lactic acid with 100% yield and a maximum volumetric productivity of 3.5 g l(-1) h(-1).

Culture Media↗
PubMed1994

An in vitro model for adhesion of bacteria to human tooth root surfaces.

A model mimicking bacterial colonization of dentine has been developed. It employs uniform particles of pulverized human tooth root tissue incubated with radioactively labelled bacteria. After incubation, the number of attaching bacteria is quantified. Attachment of Streptococcus mutans UA140, Actinomyces viscosus T14, and Lactobacillus casei 101 was found to be time dependent and complete within 1-3 h. Dissociation constants (Kd) of the interactions equalled 2.5 x 10(8) and 1.6 x 10(8) cells/ml, for Strep. mutants and A. viscosus, respectively. The Kd for L. casei could not be determined as attachment was not saturable. The putative tissue components involved in adherence were studied by determining the attachment of bacteria in the presence of competing strains. The results suggest that Strep. mutans and A. viscosus recognized and competed for the same ligand (probably collagen) in the dentine. L. casei attachment did not complete with the attachment of Strep. mutans and A. viscosus. Attachment of all strains was modified by preincubation with saliva and varied with bacterial strain and saliva donor.

Actinomyces↗