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PubMed1995

In vitro inhibition of Helicobacter pylori NCTC 11637 by organic acids and lactic acid bacteria.

In this study the effects of both pH and organic acids on Helicobacter pylori NCTC 11637 were tested. Lactobacillus acidophilus, Lact. casei, Lact. bulgaricus, Pediococcus pentosaceus and Bifidobacterium bifidus were assayed for their lactic acid production, pH and inhibition of H. pylori growth. A standard antimicrobial plate well diffusion assay was employed to examine inhibitory effects. Lactic, acetic and hydrochloric acids demonstrated inhibition of H. pylori growth in a concentration-dependent manner with the lactic acid demonstrating the greatest inhibition. This inhibition was due both to the pH of the solution and its concentration. Six strains of Lact. acidophilus and one strain of Lact. casei subsp. rhamnosus inhibited H. pylori growth where as Bifidobacterium bifidus, Ped. pentosaceus and Lact. bulgaricus did not. Concentrations of lactic acid produced by these strains ranged from 50 to 156 mmol l-1 and correlated with H. pylori inhibition. The role of probiotic organisms and their metabolic by-products in the eradication of H. pylori in vivo remains to be determined.

Acetates↗
PubMed1976

[On the metabolism of amino acids by lactic acid bacteria isolated from wine (author's transl)].

The changes in the concentrations of amino acids in the culture medium of lactic acid bacteria were determined by ion exchange chromatography after growth of 105 strains that were mainly isolated from wine. After growth of lactic acid bacteria a small but not significant decrease in the concentration of most amino acids is observed. There is apparently no difference between essential or not essential amino acids. Certain bacterial strains decompose the amino acids arginine, glutamic acid, histidine, and tyrosine completely. Other amino acids (tryptophane, aspartic acid, threonine, isoleucine, and phenylalanine) are only partially metabolized. Among 28 strains of Pediococcus cerevisiae only one strain was able to decarboxylate histidine to histamine. This was the only strain found to have this ability. Several strains of Lactobacillus brevis were able to form 4-aminobutyric acid and ornithine from glutamic acid and arginine respectively.

Amino Acids↗
PubMed2003

Two distinct pathways for the formation of hydroxy FA from linoleic acid by lactic acid bacteria.

Twenty-three of 86 strains of lactic acid bacteria transformed linoleic acid into hydroxy FA. Two distinct conversion pathways were in operation. Two strains of Lactobacillus acidophilus and a strain of Pediococcus pentosaceus produced 13(S)-hydroxy-9-octadecenoic acid 113(S)-OH 18:11 and 10,13dihydroxyoctadecanoic acid (10,13-OH 18:0) as main and minor products, respectively, whereas 13 strains, including L. casei subsp. casei, L. paracasei subsp. paracasei, L. rhamnosus, L. lactis subsp. cremoris, and Streptococcus salivarius subsp. thermophilus produced 10-hydroxy-12-octadecenoic acid (10-OH 18:1). Seven strains of L. plantarum converted linoleic acid to 10-hydroxyoctadecanoic acid (10-OH 18:0) through 10-OH 18:1. Linoleic acid at 2 g/L was converted by L. acidophilus IFO13951T to 1.3 g of 13(S)-OH 18:1 and 0.09 g of 10,13-OH 18:0 in 7 d. Lactobacillus paracasei subsp. paracasei JCM 1111 produced 10-OH 18:1 in 91% yield, and L. plantarum JCM 8341, 10-OH 18:0 in 59% yield from linoleic acid (2 g/L) under optimal conditions. To our knowledge, this is the first report on the production of 13(S)-OH 18:1 by lactic acid bacteria other than ruminal bacteria, and of 10,13-OH 18:0 by any bacteria.

Fatty Acids↗
PubMed2004

Effects of short-chain fatty acids and lactic acids on survival of Oesophagostomum dentatum in pigs.

The direct influence of intracaecal infusion of short-chain fatty acids (SCFA) and lactic acids (LA) on already established Oesophagostomum dentatum infection in cannulated pigs was investigated. We tested the hypothesis that the previously discovered anti-parasitic effect of inulin is mediated through its metabolic products SCFA and LA by infusing into cannulated pigs these compounds in amounts approximating to those produced in the pigs large intestine and caecum during the metabolism of inulin. The experiment comprised of 18 pigs--2 groups of 9 pigs in each. The normal diet used in the experiment was based on barley flour with insoluble fibre from oat husk with added soybean meal, vitamins and minerals. After 2 weeks of adaptation to the diet all the pigs were inoculated with 6,000 infective larvae of O. dentatum. Six weeks later, surgery on all pigs was performed to install cannulas into caeci. At 7 weeks post-infection (p.i.) the SCFA and LA infusion was initiated in Group 1 (experimental) pigs; at the same time pigs in Group 2 (controls) were infused with saline. At week 10 p.i., all pigs were killed and their worm burdens determined. SCFA and LA infused pigs exhibited markedly reduced fecal egg counts and worm recoveries (98 and 92% reduction, respectively, compared to saline controls). The results from this study demonstrate that SCFA and LA have a significant negative influence on established O. dentatum infection in growing pigs. The results also show that the type of dietary carbohydrates fed and its intestinal degradation can yield metabolic by products that profoundly influence helminth survival.

Animals↗
PubMed1989

[Direct gas chromatography analysis of volatile fatty acids and lactic acids in microbiological diagnosis].

The gas chromatographic analysis of short-chain fatty acids is of great significance in the rapid diagnosis of anaerobic infections and bacterial meningitis. A new analytical method is presented detecting lactic acid without prior derivatisation in addition to volatile fatty acids in the aqueous phase directly. Lactic acid levels greater than 30 mg/dl are measured in cerebrospinal fluids of patients with acute bacterial meningitis. The sole detection of acetic acid in concentrations higher than 20 mg/dl indicates aerobes in clinical materials. A high correlation exists between the determination of n-butyric acid as well as iso-valeric acid and the occurrence of anaerobic bacteria.

Bacteria, Anaerobic↗
PubMed2003

The inhibitory effect of glycolic acid and lactic acid on melanin synthesis in melanoma cells.

Alpha-hydroxy acids (AHAs) such as glycolic acid (GA) and lactic acid (LA) have been reported to be effective in treating pigmentary lesions such as melasma, solar lentigines, and postinflammatory hyperpigmentation. The mechanism of this effect might be due to epidermal remodeling and accelerated desquamation, which would result in quick pigment dispersion. However, the direct effect of AHAs on melanin synthesis has not yet been well studied. To elucidate such a direct effect of AHAs on melanogenesis, we performed melanin assays, growth curve determinations, Northern and Western blotting for melanogenic proteins [tyrosinase, tyrosinase related protein (TRP)-1 and TRP-2], and tyrosinase and, 4-dihydroxyphenylalaninechrome tautomerase enzyme activity assays using mouse B16 and human melanoma cells. GA or LA (at doses of 300 or 500 microg/ml) inhibited melanin formation in similar dose-dependent manner, without affecting cell growth. Although the mRNA and protein expression or molecular size of tyrosinase, TRP-1 and TRP-2 were not affected, tyrosinase activity was inhibited. To see whether GA and/or LA directly inhibit tyrosinase catalytic function, the effect of GA and LA on human tyrosinase purified from the melanosome-rich large granule fraction of human melanoma cells was performed. GA or LA were shown to inhibit tyrosinase enzyme activity directly, but this effect was not due to the acidity of GA or LA, because adjusting the pH to 5.6 (the pH of GA and LA at concentrations of 2500 microg/ml), did not affect tyrosinase activity. Taken together, these results show that GA and LA suppress melanin formation by directly inhibiting tyrosinase activity, an effect independent of their acidic nature. GA and LA might work on pigmentary lesions not only by accelerating the turnover of the epidermis but also by directly inhibiting melanin formation in melanocytes.

Animals↗
PubMed2000

[Effects of acute hypoxia on plasma lactic acid and lactic dehydrogenase content in pilots].

Objective. To study the effect of acute moderate hypoxia on plasma lactic acid (LA) and lactic dehydrogenase (LDH) content in pilots. Method. Concentrations of plasma LA and LDH were measured by colorimetry in 16 healthy male pilots in the early morning (6:00 a.m.), following acute moderate hypoxic exposure (10:00 a.m.) and 6 hours after returned to the ground (4:00 p.m.). 16 healthy male ground people served as control group, and their plasma LA and LDH contents were assayed at corresponding time. Result. Plasma LA after moderate hypoxic exposure in the pilot group was significantly higher than that at 6:00 a.m., 4:00 p.m., and control group (P < 0.01). While the content at 6:00 a.m., 4:00 p.m. in pilot group was not significantly different from the control group (P > 0.05). The content of plasma LDH after moderate hypoxic exposure in the pilot group was not significantly higher than that at 6:00 a.m., 4:00 p.m., and control group (P > 0.05). Conclusion. Acute moderate hypoxia can make the plasma LA content increase in pilots, and reach to the normal level within 6 h. While the LDH content has no significantly change.

Adult↗
PubMed2000

Rapid detection of meso-diaminopimelic acid in lactic acid bacteria by microwave cell wall hydrolysis.

Two innovative microwave hydrolysis procedures for rapidly detecting meso-diaminopimelic acid in lactic acid bacteria have been developed. Whole-cell hydrolysis was performed both in liquid phase and vapor phase with 6 N HCl in sealed vessels using a microwave oven equipped with pressure and temperature probes. The presence or absence of meso-diaminopimelic acid determined by TLC, after the application of liquid- and vapor-phase microwave hydrolysis procedures, gave the same qualitative results as those obtained by traditional hydrolysis. These standardized microwave hydrolysis procedures permit a drastic reduction in hydrolysis time, from 16-20 h to less than 10 min and, consequently, in the total time of meso-diaminopimelic acid analysis (less than 90 min). Microwave hydrolysis in vapor phase is particularly convenient because, besides reducing hydrolysis time, it also eliminates the successive troublesome step of HCl removal.

Cell Wall↗
PubMedDate not supplied

Glucose and sucrose fermenting capacity of homofermentative lactic acid bacteria used as starters in fermented salads.

Salads, i.e., vegetables and/or meat in an oil-in-water emulsion with a low pH due to the addition of acids, are popular in western countries. The shelf life of these salads is influenced mainly by storage temperature and the use of preservatives, i.e., sorbic and benzoic acid. Lactic acid fermentation could be an interesting novel approach to salad preparation. As part of an investigation on fermented salads, lactic acid bacteria from the genera Lactobacillus, Pediococcus and Streptococcus were screened for their capacity to ferment glucose and sucrose in a model system and in a standard salad. The temperature optimum of these strains was in the range of 34-48 degrees C. Most of these strains produced about equal amounts of L(+)- and D(-)-lactic acid. To determine the specific sugar fermenting capacity (mmol lactic acid produced per min per g dry weight) of non-growing cells of lactic acid bacteria, a semi-automated model system was used, based on monitoring the pH decrease in a phosphate buffer during conversion of sugars to lactic acid. The strains tested showed acid production rates on glucose varying between 0.03 and 0.39 mmol of acid produced per min per g dry weight (average 0.23). These glucose-grown cells showed varying, but lower fermentation rates on sucrose (0-0.25 mmol/min/g d.w., average 0.04) than sucrose-grown cells (0-0.33 mmol/min/g d.w., average 0.19). Results obtained with the model system were in good agreement with those of fermentation tests, carried out with a standard salad. Inhibition of spoilage bacteria in the standard salad could be achieved by using starter cultures with high fermenting capacity.

Animals↗
PubMed2004

Production of phenyllactic acid by lactic acid bacteria: an approach to the selection of strains contributing to food quality and preservation.

The ability of lactic acid bacteria (LAB) to produce phenyllactic (PLA) and 4-hydroxy-phenyllactic (OH-PLA) acids, metabolites involved in food quality and preservation, has been evaluated by HPLC analysis in 29 LAB strains belonging to 12 species widely used in the production of fermented foods. Metabolite production was demonstrated for all strains of the species Lactobacillus plantarum, Lactobacillus alimentarius, Lactobacillus rhamnosus, Lactobacillus sanfranciscensis, Lactobacillus hilgardii, Leuconostoc citreum, and for some strains of Lactobacillus brevis, Lactobacillus acidophilus and Leuconostoc mesenteroides subsp. mesenteroides. Strains were distinguished by analysis of variance in three groups including 15 strains that produced both metabolites (0.16-0.46 mM PLA and 0.07-0.29 mM OH-PLA), five strains accumulating in culture only PLA (0.17-0.57 mM) and nine non-producer strains (< or = 0.10 mM PLA and < or = 0.02 mM OH-PLA). Improvement of phenyllactic acid production was obtained in a selected L. plantarum strain by increasing the concentration of phenylalanine in culture and using low amounts of tyrosine.

Arsenicals↗
PubMed1995

Dissociation of serum amyloid P from C4b-binding protein and other sites by lactic acid: potential role of lactic acid in the regulation of pentraxin function.

Serum amyloid P (SAP) and C-reactive protein (CRP) are two members of the pentraxin family of proteins. These proteins associate with a variety of other materials that are found in serum under normal or pathological circumstances. This study showed that carboxylated compounds, especially lactic acid, were capable of dissociating pentraxins from several macromolecular binding sites. When measured by sucrose density gradient ultracentrifugation, complete dissociation of the complex of hSAP (human SAP) with C4b-binding protein (C4BP) occurred at > or = 5 mM lactate. Lactate dissociated the hSAP-membrane complex and prevented hSAP self-association. The only interaction that was not dissociated by 10 mM lactate was the hSAP-heparin complex. The relative efficacies of several dissociating agents were O-phosphorylethanolamine > lactate > succinate > carbonate > epsilon-amino-n-caproic acid. This suggested that the carboxyl group plus a hydrogen-bonding site on the hydrocarbon chain was important, but a charged amino group was not a contributor to function when the anion was provided by a carboxyl group. The concentration of lactic acid needed to dissociate hSAP from C4BP was dependent on protein concentration in a manner suggesting the cooperative binding of lactate (coefficient = 2) to hSAP. Pure proteins, at concentrations found in normal serum, required about 12 mM lactate for half-dissociation of the hSAP-C4BP complex. Other pentraxins also interacted with lactic acid, but with lower affinities. An important observation was that lactic acid was capable of dissociating rat CRP from lipoproteins in rat serum. Human CRP bound very weakly to lactate, so that lactate probably is not a significant regulator of this pentraxin.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗
PubMed2006

Automated no-carrier-added synthesis of [1-11C]-labeled D- and L-enantiomers of lactic acid.

The first purely chemical method for automated no-carrier-added synthesis of [1-(11)C]-labeled d(R)- and l(S)-2-hydroxypropanoic acid (lactic acid) was developed for experimental neurophysiology studies and position emission tomography (PET) diagnosis. Starting from sodium 1-hydroxyethanesulfonate and [(11)C]HCN (trapped as [(11)C]KCN) the intermediate dl-(R,S)-[1-(11)C]-2-hydroxypropanenitrile was prepared. Its rapid acid hydrolysis gave dl-(R,S)-[1-(11)C]lactic acid, which was isolated by preparative reversed phase HPLC and automatically injected on a second preparative C(18) HPLC column coated with a chiral selector, where both [1-(11)C]lactic acid enantiomers were separated by chiral ligand-exchange chromatography. Two novel chiral selectors for HPLC enantiomeric separation of alpha-hydroxy acids, namely d(R)- or l(S)-2-amino-3-methyl-3-(5-phenylpentylsulfanyl)-butanoic acid were utilized for the preparative HPLC separation of the [1-(11)C]lactic acid enantiomers. The preparation of the selectors and the coating procedure for the manufacturing of the preparative chiral HPLC columns are described. A highly efficient trap for [(11)C]HCN is presented. The whole radiosynthesis is automated, takes about 45 min and leads to more than 80% decay corrected overall radiochemical yield of each enantiomer (up to 2.5 GBq) with over 99% radiochemical, chemical and enantiomeric purity. The specific activity at the end of the synthesis is about 400 GBq/micromol.

Carbon Radioisotopes↗
PubMed1982

Gas-liquid chromatographic analysis of synovial fluid. Succinic acid and lactic acid as markers for septic arthritis.

Nonvolatile short-chain fatty acids from 80 synovial fluids were quantified by gas-liquid chromatography. Succinic acid was detectable in all 23 septic synovial fluids infected with either gram-positive or gram-negative organisms and in only 5 of 57 nonseptic synovial fluids. Lactic acid was present in all of the effusions but was correlated with septic arthritis only when present in concentrations greater than 250 mg%. Neither short-chain fatty acid was more sensitive than high white blood cell counts (greater than 50,000 mm3) or depressed glucose concentration (less than 40 mg/dl) in diagnosing septic arthritis before antibiotic therapy; however, the detection of succinic acid was helpful in identifying patients with septic arthritis who had been given antibiotic treatment before arthrocentesis. Thus, gas-liquid chromatography, a rapid and sensitive method for the detection of short-chain fatty acids, may complement the currently available methods used to diagnose septic arthritis.

Arthritis, Infectious↗