Lactic Acid-producing Bacteria (lactic + acid-producing_bacteria)

Distribution by Scientific Domains

Selected Abstracts

Probiotics and their fermented food products are beneficial for health

S. Parvez
Abstract Probiotics are usually defined as microbial food supplements with beneficial effects on the consumers. Most probiotics fall into the group of organisms' known as lactic acid-producing bacteria and are normally consumed in the form of yogurt, fermented milks or other fermented foods. Some of the beneficial effect of lactic acid bacteria consumption include: (i) improving intestinal tract health; (ii) enhancing the immune system, synthesizing and enhancing the bioavailability of nutrients; (iii) reducing symptoms of lactose intolerance, decreasing the prevalence of allergy in susceptible individuals; and (iv) reducing risk of certain cancers. The mechanisms by which probiotics exert their effects are largely unknown, but may involve modifying gut pH, antagonizing pathogens through production of antimicrobial compounds, competing for pathogen binding and receptor sites as well as for available nutrients and growth factors, stimulating immunomodulatory cells, and producing lactase. Selection criteria, efficacy, food and supplement sources and safety issues around probiotics are reviewed. Recent scientific investigation has supported the important role of probiotics as a part of a healthy diet for human as well as for animals and may be an avenue to provide a safe, cost effective, and ,natural' approach that adds a barrier against microbial infection. This paper presents a review of probiotics in health maintenance and disease prevention. [source]

Growth-inhibiting effects of seco-tanapartholides identified in Artemisia princeps var. orientalis whole plant on human intestinal bacteria

S.-H. Cho
Abstract Aims: The present work aimed at isolating antibacterial constituents from the whole plant of Artemisia princeps var. orientalis active towards nine human intestinal bacteria. Methods and Results: The growth-inhibiting activities of materials derived from the Artemisia whole plant towards test bacteria were examined using an impregnated paper disc method. The biologically active constituents of the Artemisia whole plant were characterized as the sesquiterpene lactones seco-tanapartholides A and B by spectroscopic analysis. In a test using 1 mg per disc, seco-tanapartholides A and B produced a clear inhibitory effect against Clostridium perfringens, Bacteroides fragilis and Staphylococcus aureus. These compounds did not affect the growth of test lactic acid-producing bacteria (Bifidobacterium adolescentis, Bif. breve, Lactobacillus acidophilus and Lact. casei) and Escherichia coli, whereas weak growth inhibition towards Bif. bifidum was observed. At 05 mg per disc, seco-tanapartholides A and B exhibited moderate growth inhibition towards Cl. perfringens but weak growth inhibition towards Bact. fragilis and Staph. aureus. Conclusions: Inhibitory action of seco-tanapartholides A and B towards specific bacteria without any adverse effects on lactic acid-producing bacteria may be an indication of at least one of the pharmacological actions of A. princeps var. orientalis whole plant. Significance and Impact of the Study: These naturally occurring Artemisia whole plant-derived materials could be useful as a new preventive agent against various diseases caused by harmful intestinal bacteria such as clostridia. [source]

Raw potato starch and short-chain fructo-oligosaccharides affect the composition and metabolic activity of rat intestinal microbiota differently depending on the caecocolonic segment involved

G.M. Le Blay
Abstract Aims:In vitro studies have suggested that fructo-oligosaccharides (FOS) and resistant starch (two fermentable non-digestible carbohydrates) display different fermentation kinetics. This study investigated whether these substrates affect the metabolic activity and bacterial composition of the intestinal microflora differently depending on the caecocolonic segment involved. Methods and Results: Eighteen rats were fed a low-fibre diet (Basal) or the same diet containing raw potato starch (RPS) (9%) or short-chain FOS (9%) for 14 days. Changes in wet-content weights, bacterial populations and metabolites were investigated in the caecum, proximal and distal colon and faeces. Both substrates exerted a prebiotic effect compared with the Basal diet. However, FOS increased lactic acid-producing bacteria (LAPB) throughout the caecocolon and in faeces, whereas the effect of RPS was limited to the caecum and proximal colon. As compared with RPS, FOS doubled the pool of caecal fermentation products, while the situation was just the opposite distally. This difference was mainly because of the anatomical distribution of lactate, which accumulated in the caecum with FOS and in the distal colon with RPS. Faeces reflected these impacts only partly, showing the prebiotic effect of FOS and the metabolite increase induced by RPS. Conclusions: This study demonstrates that FOS and RPS exert complementary caecocolonic effects. Significance and Impact of the study: The RPS and FOS combined ingestion could be beneficial by providing health-promoting effects throughout the caecocolon. [source]

A differential medium for lactic acid-producing bacteria in a mixed culture

H.M. Lee
Abstract Aims:, Modified deMan-Rogosa Sharpe agar containing bromophenol blue (mMRS-BPB) was tested as a medium for counting and differentiation of each lactic acid-producing bacterium (LAB), especially in a mixed culture. Methods and Results:, Type strains of 10 LAB species (Lactobacillus acidophilus, L. brevis, L. bulgaricus, L. gasseri, L. paracasei, L. plantarum, L. reuteri, Weissella confusa, Bifidobacterium bifidum and B. infantis) and five commercial yogurts were inoculated on plate count agar with bromocresol purple, mMRS, and mMRS-BPB. Each type strain showed more clearly formed colonies on the three media under anaerobic conditions than under aerobic conditions. Especially each type strain produced colonies with specific characteristics of each species on mMRS-BPB. Commercial yogurts produced the largest number of colonies with various shapes and colours on mMRS-BPB. Conclusions:, Modified deMan-Rogosa Sharpe agar containing bromophenol blue under anaerobic conditions is appropriate for counting and differentiating each LAB in a mixed culture. Significance and Impact of the Study:, Modified deMan-Rogosa Sharpe agar containing bromophenol blue will be useful in isolation and enumeration of each LAB from fermented foods as well as intestinal microflora. [source]