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PubMed2004

Genome data mining of lactic acid bacteria: the impact of bioinformatics.

Lactic acid bacteria (LAB) have been widely used in food fermentations and, more recently, as probiotics in health-promoting food products. Genome sequencing and functional genomics studies of a variety of LAB are now rapidly providing insights into their diversity and evolution and revealing the molecular basis for important traits such as flavor formation, sugar metabolism, stress response, adaptation and interactions. Bioinformatics plays a key role in handling, integrating and analyzing the flood of 'omics' data being generated. Reconstruction of metabolic potential using bioinformatics tools and databases, followed by targeted experimental verification and exploration of the metabolic and regulatory network properties, are the present challenges that should lead to improved exploitation of these versatile food bacteria.

Adaptation, Biological↗
PubMed2000

[L-lactic acid fermentation by immobilized Rhizopus oryzae in a three-phase fluidized-bed].

L-lactic acid fermentation in a three-phase fluidized-bed bioreactor was studied by using immobilized Rhizopus oryzae cells with polyurethane particles as supporter. The results indicated that the immobilized cells were stable after used for 8 batches repeatedly. The rate and the yield of lactic acid fermentation with glucose as carbon source were 19.1 g h-1.L (bead)-1 and 82.5%, respectively. With the hydrolyzate of corn cob residue from xylose manufacturer by cellulase hydrolysis, the yield of lactic acid reached 71.9%.

Bioreactors↗
PubMed1987

The effect of valproic acid on the 5-hydroxyindoleacetic, homovanillic and lactic acid levels of cerebrospinal fluid.

In this study the cisternal cerebrospinal fluid (CSF) contents of 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) were sequentially measured in free-moving rats which were administered 50-500 mg X kg-1 valproic acid. Animals receiving 100-500 mg X kg-1 valproic acid showed significant increases in CSF 5-HIAA and HVA content, with maximal accumulation rates of 1.80-2.10 and 0.25-0.30 nmol X ml-1 X h-1, respectively, being reached at the 250-mg X kg-1 dose. The combination of valproic acid 500 mg X kg-1 and probenecid 300 mg X kg-1 failed to increase the accumulation rates of 5-HIAA and HVA over those seen with valproic acid 500 mg X kg-1 or probenecid 300 mg X kg-1 alone. This pattern of change indicates that valproic acid and probenecid share a common site of action in blocking the clearance of 5-HIAA and HVA from CSF. The tranquillizer diazepam produced progressive increases in CSF 5-HIAA and HVA content which suggested a similar action to that of valproic acid and probenecid. The anticonvulsants phenytoin and phenobarbital produced selective increases in 5-HIAA, whereas the tranquillizer chlorpromazine produced proportionally larger increases in HVA, changes which seem to indicate a more selective effect of these drugs on the serotonergic or dopaminergic systems, respectively. Valproic acid was associated with increases in CSF lactate which occurred in the absence of similar increases of blood or tissue lactate. This indicated that valproic acid, like probenecid, can inhibit the monocarboxylic acid transport system which removes lactate from the CSF.

Animals↗
PubMed1993

Antagonistic activity of two strains of lactic acid bacteria against Listeria monocytogenes and Yersinia enterocolitica in a model fish product at 5 degrees C.

The antagonistic activity of lactic acid bacteria against one strain of Listeria monocytogenes, Scott A and one strain of Yersinia enterocolitica serotype O:3 was studied by using either a strain of a Leuconostoc spp. or a Lactobacillus plantarum strain. Each of the two potential pathogenic, psychrotrophic bacteria were inoculated with either of the two lactic acid bacteria in sterile shrimp extracts containing citric acid (pH 5.8 and 6.0) and in some experiments also 3% (w/v) NaCl. The samples were incubated at 5 degrees C. Antagonistic effect was obtained with both lactic acid bacteria against both pathogenic organisms, with the effect depending on inoculation levels of the pathogenic organism, the lactic acid bacteria strain and media composition.

Animals↗
PubMed2003

Antagonistic effect of chosen lactic acid bacteria strains on Salmonella species in meat and fermented sausages.

The aim of this study was to determine of influence of 15 strains of lactic acid bacteria on the growth of 7 Salmonella spp. strains in model set-ups, and in meat and ripened fermented sausages. The investigations were performed within the framework of three alternate stages which differed in respect to the products studied, the number of Lactobacillus spp. strains and, partly, methodological approach. The ratio between lactic acid bacteria and Salmonella strains studied was, depending on the alternate, 1:1, 1:2 and 2:1, respectively. The investigations also covered the water activity (a(w)) and pH of the tested products. The results obtained are shown in 12 figures and suggest that all the lactic acid bacteria strains used within the framework of the model set-ups showed antagonistic effect on all the Salmonella spp. strains. However, these abilities were not observed with respect to some lactic acid bacteria strains in meat and fermented sausage. The temperature and length of the incubation period of sausages, but not a(w) and pH, were found to have a distinct influence on the antagonistic interaction between the bacteria.

Animals↗
PubMed2001

Phenotypic and molecular identification and clustering of lactic acid bacteria and yeasts from wheat (species Triticum durum and Triticum aestivum) sourdoughs of Southern Italy.

The microflora of 25 wheat sourdoughs from the Apulia region, Southern Italy, was characterized. The sourdoughs were mainly produced from Triticum durum wheat. The number of lactic acid bacteria and yeasts ranged from ca. log 7.5 to log 9.3 colony forming units (cfu)/g and from log 5.5 to log 8.4 cfu/g, respectively. About 38% of the 317 isolates of lactic acid bacteria were identified by conventional physiological and biochemical tests. Phenotypic identification was confirmed by 16S rDNA and 16S/23S rRNA spacer region PCR. Overall, 30% of the isolates were identified as Lactobacillus sanfranciscensis, 20% as Lb. alimentarius, 14% as Lb. brevis, 12% as Leuconostoc citreum, 7% as Lb. plantarum, 6% as Lactococcus lactis subsp. lactis, 4% as Lb. fermentum and Lb. acidophilus, 2% as Weissella confusa and 1% as Lb. delbrueckii subsp. delbrueckii. Some of these species have not been previously isolated from sourdoughs. Since bakers yeast is widely used in sourdough production, Saccharomyces cerevisiae was largely found. The phenotypical relationships within the main lactic acid bacteria identified were established by using cluster analysis. A microbial map of the 25 sourdoughs was plotted showing characteristic associations among lactic acid bacteria and differences in the lactic acid bacteria species which were mainly due to the species of wheat flour, use of bakers yeast and type of bread.

Bread↗
PubMed2004

Quantitative 2H NMR at natural abundance can distinguish the pathway used for glucose fermentation by lactic acid bacteria.

For any given metabolic pathway, isotope redistribution coefficients (a(ij)) that characterize the specific derivation of each hydrogen atom can be defined. By using quantitative deuterium NMR, the redistribution of deuterium at natural abundance in lactic acid produced by the bacterial fermentation of glucose has been determined for each non-labile hydrogen atom of glucose or water and the hydrogen atoms of lactic acid. Distinct differences are observed in the lactic acid isolated from Lactococcus lactis and Leuconostoc mesenteroides that can be interpreted in terms of the different fermentative pathways used. Specifically, the affiliations observed between the H1, H3, and H4 positions of glucose with methyl and hydroxymethylene of lactic acid can give quantitative information on whether the glycolytic or the reductive pentose-phosphate pathway was involved in glucose catabolism.

Fermentation↗
PubMed1984

A rapid chemical spot test for the detection of lactic acid as an indicator of microbial spoilage in preserved foods.

A rapid method for the detection of lactic acid in preserved foods has been developed, based upon a chemical spot test which does not require solvent extraction or derivatisation of the lactic acid in the sample. The test can be completed within 5 min and was shown to confirm microbial spoilage detected by cultural techniques in a range of preserved foods. In addition the test was able to indicate microbial spoilage in samples where cultural techniques failed because the spoilage organisms were dead. The test may not be appropriate for products which have a naturally high lactic acid content.

Food Analysis↗
PubMed2000

Dose-response relationships. A model for describing interactions, and its application to the combined effect of nisin and lactic acid on Leuconostoc mesenteroides.

As well as producing bacteriocins, many lactic bacteria produce other potentially toxic compounds or growth inhibitors, especially lactic acid, which may interfere in the assays commonly used to quantify these peptides. A systematic set of modifications is proposed which, when applied to the logistical equation, enable it to describe the combined (but not additive) effects of two or more active principles. The general model thus derived is applied to the interaction of nisin and lactic acid on Leuconostoc mesenteroides.

Anti-Bacterial Agents↗
PubMed1977

Cerebrospinal fluid lactic acid levels in meningitis.

Measurement of cerebrospinal fluid lactic acid by gas liquid chromatography and by an enzymatic Monotest lactate test was evaluated for the early detection of bacterial meningitis in 396 patients. Spinal fluid specimens from 62/62 patients with a bacterial or mycoplasma etiology yielded lactate levels greater than the upper limits of normal, whereas specimens from 334 patients with no bacterial involvement gave values within the normal range. The duration of elevated CSF lactate values coincided with the clinical response to therapy. When considered along with the history and physical examination of the patient, determination of lactic acid proved to be a rapid and reliable diagnostic test for the early detection of untreated as well as partially treated pyogenic meningitis.

Adolescent↗
PubMed1994

Effect of acetyl-L-carnitine on recovery of brain phosphorus metabolites and lactic acid level during reperfusion after cerebral ischemia in the rat--study by 13P- and 1H-NMR spectroscopy.

The effects of acetyl-L-carnitine (ALCAR) treatment on brain energy state recovery and lactic acid levels following 20 min ischemia and 2, 24 and 48 h reperfusion were investigated by 31P and 1H-NMR spectroscopy. Transient forebrain ischemia was induced by four-vessel occlusion method in fed 6-month-old Fischer rats. ALCAR or saline was administered by intraperitoneal route immediately after 20 min ischemia and again at 1, 4, 24 and 30 h during reperfusion. Twenty-min severe forebrain ischemia was associated with a marked decrease in phosphocreatine (PCr) and ATP levels and a corresponding increase in lactic acid, inorganic phosphate (Pi), AMP, creatine, glycerol 3-phosphate and alanine levels. Following reperfusion, a general tendency to restore pre-ischemic metabolite levels was observed. However, after 2 h reperfusion in saline-treated rats, lactic acid and Pi levels remained significantly higher, while ATP levels were still significantly lower than in non-ischemic controls. On the contrary, in ALCAR-treated animals a complete recovery of all metabolites including Pi and ATP was observed, while PCr levels were even more elevated compared with those in saline-treated rats. Furthermore lactic acid content was significantly lower than that in both saline-treated and non-ischemic control rats. It is concluded that a potential therapeutic role may be claimed for ALCAR in the treatment of cerebral ischemia through mechanisms that include faster recovery and improvement of brain energy production as well as a decreased lactic acid content during early post-ischemic reperfusion.

Acetylcarnitine↗
PubMedDate not supplied

Sub-micrometer-sized biodegradable particles of poly(L-lactic acid) via the gas antisolvent spray precipitation process.

Sub-micrometer-sized particles of poly(L-lactic acid) may be formed by using near-critical or supercritical carbon dioxide as an antisolvent to precipitate poly(L-lactic acid) from droplets of methylene chloride solution sprayed into a carbon dioxide continuous phase. Particle sizes may be controlled by varying the density of the carbon dioxide; at constant temperature in the supercritical region, higher carbon dioxide densities yield larger particles. Two methods (one batch and one continuous) for introducing the poly(L-lactic acid) solutions into carbon dioxide are demonstrated. Although the two methods use very different mechanisms for forming the droplets, similar particle sizes are observed as a function of carbon dioxide density. We suggest that mass transport, rather than jet breakup and hydrodynamics, controls particle sizes in the near-critical and supercritical regions.

Biodegradation, Environmental↗
PubMed2002

Surface engineering of poly(DL-lactic acid) by entrapment of alginate-amino acid derivatives for promotion of chondrogenesis.

Alginate-amino acid derivatives were explored to engineer poly(DL-lactic acid)(PDL-LA) as glycocalyx-like surface to promote cell adhesion and growth. Four different kinds of alginate-amino acid derivatives were synthesized to mimic the glycocalyx of cell membrane to promote chondrogenesis. The alginate-amino acid derivatives were characterized by FT-IR, 1H NMR and UV spectra and the amino acid content on alginate-amino acid derivatives was given by ninhydrin-UV method. A new strategy, entrapment, was then employed to modify PDL-LA membranes with alginate and its amino acid derivatives. The results of XPS, ATR-FTIR and contact angle confirmed that a stable thin film of alginate and its amino acid derivatives can be entrapped on the surface of PDL-LA membrane. The chondrocyte cytocompatibility test and MTT assays indicated that the alginate-amino acid derivatives modified PDL-LA membranes could promote chondrogenesis. The novel surface treatment method may have potentials for tissue engineering and other biomedical applications.

Alginates↗
PubMed1990

In vivo characteristics of low molecular weight copolymers composed of L-lactic acid and various DL-hydroxy acids as biodegradable carriers for drug delivery systems.

Low molecular weight and amorphous copolyesters composed of 70 mol% L-lactic acid and 30 mol% DL-hydroxy acids such as DL-lactic acid, DL-alpha-hydroxy-n-butyric acid, DL-alpha-hydroxyisovaleric acid and DL-alpha-hydroxyisocaproic acid were synthesized by direct copolycondensation in the absence of catalysts, to evaluate their in vivo capabilities as biodegradable carriers for drug delivery systems. For this purpose, the copolyester was moulded into a small cylindrical specimen under melt-pressing technique and implanted subcutaneously in the back of male adult rats. The in vivo degradation pattern can be subdivided into three types: the formations of parabolic type (L-LA/DL-HBA copolymer), linear type (L-LA/DL-LA copolymer) and S type (L-LA/DL-HIVA and L-LA/DL-HICA copolymers). A luteinizing hormone-releasing hormone agonist, des-Gly10-(D-Leu6)-LH-RH ethylamide monoacetate (LH-RH agonist), was incorporated into the small cylinders of copolyester formulations, of which the strongest pharmacological influence was observed in a copoly(L-LA/DL-HICA) formulation system, resulting in the maintenance of effective pharmacological influence throughout an experimental period of 15 wk, at which the in vivo release rate of LH-RH agonist was held constant at approximately 45 micrograms/d.

Animals↗
PubMed1993

Common mechanistic action of bacteriocins from lactic Acid bacteria.

The influence of four bacteriocins from lactic acid bacteria on the proton motive force (PMF) of sensitive organisms was investigated. Pediocin PA-1 (20 mug/ml) and leuconocin S (48.5 mug/ml) mediated total or major PMF dissipation of energized Listeria monocytogenes Scott A cells in a concentration-dependent manner, as has been shown for nisin. Lactacin F (13.5 mug/ml) caused 87% PMF depletion of energized Lactobacillus delbrueckii ATCC 4797 cells, also in a concentration-dependent fashion. The energy requirements for the activity of these four bacteriocins were determined by using the ionophores nigericin and valinomycin to carry out partial and specific deenergization of the target organisms. Pediocin PA-1, leuconocin S, and lactacin F acted in an energy-independent manner, whereas the activity of nisin was confirmed to be energy dependent. These results together with published reports on other bacteriocins suggest that the bacteriocins of lactic acid bacteria share a common mechanism, the depletion of PMF.

Journal Article↗
PubMed1999

[Evaluation of lactic acid levels in blood of patients with ischemic stroke in the earliest stage of the disease].

The aim of the study was the assessment of concentrations of lactic acid in the blood of patients with mild course and severe course of ischaemic stroke in the earliest stage of the disease. The subject of the study were 20 patients with a mild ischaemic stroke and 20 patients with a severe one on its 1st, 3rd and 7th day. Enzymatic method for determining lactic acid content in the blood was used (the kits Test-Combination Lactate fully enzymatic of Boehringer Mannheim). In the group of patients with mild ischaemic stroke increase values of lactic acid were shown on all days of the disease, but the differences were statistically insignificant. In patients with severe ischaemic stroke these values were higher than in controls, and the differences were statistically significant. The study showed a positive correlation between high concentrations of lactic acid and severe clinical condition of patients.

Cerebral Infarction↗
PubMed1998

Lactic acid bacteria found in fermented fish in Thailand.

Forty-seven strains of homofermentative rod-shaped and 5 heterofermentative sphere-shaped lactic acid bacteria were isolated from 4 kinds of fermented fish (pla-ra, pla-chom, kung-chom, and hoi-dong) in Thailand. These bacteria were separated into four groups by phenotypic and chemotaxonomic characteristics, including fluorometric DNA-DNA hybridization. Five strains (Group I) contained meso-diaminopimelic acid in the cell wall. Four strains were identified as Lactobacillus pentosus, and one strain was L. plantarum. Tested strains of this group produced DL-lactic acid. The rest of the rod-shaped bacteria, 23 strains (Group II) and 19 strains (Group III), lacked meso-diaminopimelic acid in the cell wall and were identified as L. farciminis and Lactobacillus species, respectively. The tested strains of these groups produced L-lactic acid. The amount of cellular fatty acids of C16:0 and C18:1, and the DNA base compositions were significant for differentiating the strains in Groups II and III. Five strains of cocci in chains (Group IV) produced gas from glucose. The tested strains of this group produced d-lactic acid. They were identified as a Leuconostoc species. The distribution of these bacteria in fermented fish in Thailand is discussed.

Journal Article↗