Topic
Leuconostoc
About: Leuconostoc is a research topic. Over the lifetime, 1859 publications have been published within this topic receiving 65937 citations.
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TL;DR: Fourteen bacteriocin-producing strains from the genera Lactobacillus, Leuconostoc, Pediococcus, and Lactococcus were evaluated for their ability to inhibit the growth of eight strains of Listeria monocytogenes.
365 citations
TL;DR: The results demonstrate that DGGE fingerprinting and rRNA quantification should allow workers to precisely and rapidly characterize the microbial assemblage in a spontaneous lactic acid fermented food and strongly suggest that cultivation-independent methods should be used to study traditional fermented foods.
Abstract: The distribution of microorganisms in pozol balls, a fermented maize dough, was investigated by a polyphasic approach in which we used both culture-dependent and culture-independent methods, including microbial enumeration, fermentation product analysis, quantification of microbial taxa with 16S rRNA-targeted oligonucleotide probes, determination of microbial fingerprints by denaturing gradient gel electrophoresis (DGGE), and 16S ribosomal DNA gene sequencing. Our results demonstrate that DGGE fingerprinting and rRNA quantification should allow workers to precisely and rapidly characterize the microbial assemblage in a spontaneous lactic acid fermented food. Lactic acid bacteria (LAB) accounted for 90 to 97% of the total active microflora; no streptococci were isolated, although members of the genus Streptococcus accounted for 25 to 50% of the microflora. Lactobacillus plantarum and Lactobacillus fermentum, together with members of the genera Leuconostoc and Weissella, were the other dominant organisms. The overall activity was more important at the periphery of a ball, where eucaryotes, enterobacteria, and bacterial exopolysacharide producers developed. Our results also showed that the metabolism of heterofermentative LAB was influenced in situ by the distribution of the LAB in the pozol ball, whereas homolactic fermentation was controlled primarily by sugar limitation. We propose that starch is first degraded by amylases from LAB and that the resulting sugars, together with the lactate produced, allow a secondary flora to develop in the presence of oxygen. Our results strongly suggest that cultivation-independent methods should be used to study traditional fermented foods.
345 citations
TL;DR: Problems encountered with resistance testing are clearly demonstrated, in that the breakpoint values are often inadequately identified, resistance genes may be present but silent, and the genetic basis and associated resistance mechanisms toward some antibiotics are still unknown.
Abstract: The antibiotic resistances of 45 lactic acid bacteria strains belonging to the genera Lactobacillus, Streptococcus, Lactococcus, Pediococcus, and Leuconostoc were investigated. The objective was to determine antibiotic resistances and to verify these at the genetic level, as is currently suggested by the European “qualified presumption of safety” safety evaluation system for industrial starter strains. In addition, we sought to pinpoint possible problems in resistance determinations. Primers were used to PCR amplify genes involved in β-lactam antibiotic, chloramphenicol, tetracycline, and erythromycin resistance. The presence of ribosomal protection protein genes and the ermB gene was also determined by using a gene probe. Generally, the incidences of erythromycin, chloramphenicol, tetracycline, or β-lactam resistances in this study were low (
327 citations
TL;DR: A method to screen lactobacilli for production of unique antimicrobial substances and the discovery of reuterin is described, capable of inhibiting growth of species representing all bacterial genera tested thus far.
Abstract: Lactobacillus reuteri resides in the gastrointestinal tract of humans, swine, poultry and other animals. Resting cells of this species convert glycerol into a potent, broad-spectrum antimicrobial substance termed reuterin. Reuterin is a low molecular weight, neutral, water soluble compound, capable of inhibiting growth of species representing all bacterial genera tested thus far, including: Escherichia, Salmonella, Shigella, Proteus, Pseudomonas, Clostridium and Staphylococcus. Also affected, but to a lesser degree, are lactic acid bacteria belonging to the genera Streptococcus, Pediococcus, Leuconostoc, and Lactobacillus. In this report we describe a method to screen lactobacilli for production of unique antimicrobial substances and the discovery of reuterin.
318 citations
TL;DR: The enzymatic synthesis of fructans (levan and inulin) is poorly documented at the molecular level, but the field of Streptococcus and Leuconostoc glucansucrases (glucosyltransferases and dextransucrase) has been well studied, both at the mechanistic and gene structure levels.
315 citations