Project description:The ability to produce diacetyl from pyruvate and l-serine was studied in various strains of Pediococcus pentosaceus and Pediococcus acidilactici isolated from cheese. After being incubated on both substrates, only P. pentosaceus produced significant amounts of diacetyl. This property correlated with measurable serine dehydratase activity in cell extracts. A gene encoding the serine dehydratase (dsdA) was identified in P. pentosaceus, and strains that showed no serine dehydratase activity carried mutations that rendered the gene product inactive. A functional dsdA was cloned from P. pentosaceus FAM19132 and expressed in Escherichia coli. The purified recombinant enzyme catalyzed the formation of pyruvate from L- and D-serine and was active at low pH and elevated NaCl concentrations, environmental conditions usually present in cheese. Analysis of the amino acid profiles of culture supernatants from dsdA wild-type and dsdA mutant strains of P. pentosaceus did not show differences in serine levels. In contrast, P. acidilactici degraded serine. Moreover, this species also catabolized threonine and produced alanine and α-aminobutyrate.
Project description:This report describes the first case of persistent bacteremia with endocarditis caused by Pediococcus acidilactici in a 32-year-old male with a history of short gut syndrome following a small bowel transplant. The results showed the utility of sequencing the intergenic spacer region for species identification and successful treatment using daptomycin.
| S-EPMC3295129 | biostudies-literature
Project description:Full genome analysis of lactic acid bacteria strains with excellent probiotic properties
Project description:We used a whole genome array containing 97.4 % of the annotated genes of Lactobacillus acidophilus NCFM, a probiotic culture that belongs to the lactic acid bacteria group, to identify genes that are differentially expressed under several stress conditions. Keywords: Stress response
Project description:Pediococcus acidilactici MA18/5M is a commercially available probiotic that is widely used in swine, poultry, aquaculture feeds, and human dietary supplements. We prepared a genome sequence for this strain consisting of 2 scaffolds totaling 1,992,928 bases including gaps for a total of 3,346 bases and a G+C content of 42%.
Project description:Lactate oxidases belong to a group of FMN-dependent enzymes and they catalyze a conversion of lactate to pyruvate with a release of hydrogen peroxide. Hydrogen peroxide is also utilized as a read out in biosensors to quantitate lactate levels in biological samples. Aerococcus viridans lactate oxidase is the best characterized lactate oxidase and our knowledge of lactate oxidases relies largely to studies conducted with that particular enzyme. Pediococcus acidilactici lactate oxidase is also commercially available for e.g. lactate measurements, but this enzyme has not been characterized in detail before. Here we report structural characterization of the recombinant enzyme and its co-factor dependent oligomerization. The crystal structures revealed two distinct conformations in the loop closing the active site, consistent with previous biochemical studies implicating the role of loop in catalysis. Despite the structural conservation of active site residues, we were not able to detect either oxidase or monooxygenase activity when L-lactate was used as a substrate. Pediococcus acidilactici lactate oxidase is therefore an example of a misannotation of an FMN-dependent enzyme, which catalyzes likely a so far unknown oxidation reaction.
