Search results for "Bacillus"
showing 10 items of 774 documents
In situ activity of a bacteriocin-producing Lactococcus lactis strain. Influence on the interactions between lactic acid bacteria during sourdough fe…
2005
Aims: To biochemically characterize the bacteriocin produced by Lactococcus lactis ssp. lactis M30 and demonstrate its effect on lactic acid bacteria (LAB) during sourdough propagation. Methods and Results: A two-peptide bacteriocin produced by L. lactis ssp. lactis M30 was purified by ion exchange, hydrophobic interaction and reversed phase chromatography. Mass spectrometry of the two peptides and sequence analysis of the ltnA2 gene showed that the bacteriocin was almost identical to lacticin 3147. During a 20-day period of sourdough propagation the stability of L. lactis M30 was demonstrated, with concomitant inhibition of the indicator strain Lactobacillus plantarum 20, as well as the …
Cloning, deletion, and characterization of PadR, the transcriptional repressor of the phenolic acid decarboxylase-encoding padA gene of Lactobacillus…
2004
ABSTRACTLactobacillus plantarumdisplays a substrate-induciblepadAgene encoding a phenolic acid decarboxylase enzyme (PadA) that is considered a specific chemical stress response to the inducing substrate. The putative regulator ofpadAwas located in thepadAlocus based on its 52% identity with PadR, thepadAgene transcriptional regulator ofPediococcus pentosaceus(L. Barthelmebs, B. Lecomte, C. Diviès, and J.-F. Cavin, J. Bacteriol.182:6724-6731, 2000). Deletion of theL. plantarum padRgene clearly demonstrates that the protein it encodes is the transcriptional repressor of divergently orientedpadA. ThepadRgene is cotranscribed with a downstream open reading frame (ORF1), the product of which m…
A taxonomic survey of lactic acid bacteria isolated from wheat (Triticum durum) kernels and non-conventional flours
2007
In order to explore the correspondence between raw material- and mature sourdough-lactic acid bacterial (LAB) communities, 59 Italian wheat (Triticum durum) grain samples, one bran and six non-conventional flour samples were analyzed through a culture-dependent approach. The highest cell count by an agar medium specific for LAB was 2.16 log CFU/g. From about 2300 presumptive LAB (Gram-positive and catalase-negative) colonies collected, a total of 356 isolates were subjected to identification by a genetic polyphasic strategy consisting of RAPD-PCR analysis, partial 16S rRNA gene sequencing, species-specific and multiplex PCRs. The isolates were recognized as 137 strains belonging to Aerococc…
Rapid 96-well plates DNA extraction and sequencing procedures to identify genome-wide transposon insertion sites in a difficult to lyse bacterium: La…
2014
International audience; Random transposon mutagenesis followed by adequate screening methods is an unavoidable procedure to characterize genetics of bacterial adaptation to environmental changes. We have recently constructed a mutant library of Lactobacillus casei and we aimed to fully annotate it. However, we have observed that, for L. casei which is a difficult to lyse bacterium, methods used to identify the transposon insertion site in a few mutants (transposon rescue by restriction and recircularization or PCR-based methods) were not transposable for a larger number because they are too time-consuming and sometimes not reliable. Here, we describe a method for large-scale and reliable id…
Identification of Carnobacterium, Lactobacillus, Leuconostoc and Pediococcus by rDNA-based techniques
2003
Summary Ribosomal DNA-based techniques including the analysis of profiles generated by ISR amplification, ISR restriction and ARDRA have been evaluated as molecular tools for identifying Carnobacterium, Lactobacillus, Leuconostoc and Pediococcus. They have been applied for the molecular characterization of 91 strains with the following identities: eight Carnobacterium including the eight type species of the genus; 61 Lactobacillus including 40 type strains out of 45 species, 13 Leuconostoc, out of them 11 are type strains and three are subspecies of Lc. mesenteroides; and nine strains representing the six species of genus Pediococcus. The genetic relationship displayed between these species…
Lactobacillus aquaticus sp. nov., isolated from a Korean freshwater pond.
2009
A Lactobacillus strain, IMCC1736T, was isolated recently from a Korean freshwater pond following an extensive study of the microbial community in this ecosystem. Its 16S rRNA gene was sequenced and phylogenetic analysis placed this strain within the Lactobacillus salivarius group, closely related to Lactobacillus satsumensis NRIC 0604T, with 97.9% sequence similarity. In the present work, the taxonomic status of strain IMCC1736T has been re-evaluated. It was characterized phylogenetically, genotypically and phenotypically and, based on DNA-DNA hybridization values, this strain represents a novel Lactobacillus species. Strain IMCC1736T can be differentiated genotypically from its closest rel…
Heterotrophic microorganisms in deteriorated medieval wall paintings in southern Italian churches
2008
The Campania region in southern Italy is noted for its large number of churches that harbour invaluable frescoes, dated from the beginnings of the 4th up to the 13th century. The wall paintings represent an integral part of the monuments, and their deterioration constitutes a potentially significant loss for the world's cultural heritage. Heterotrophic microorganisms such as bacteria and mould can grow on the surface of paintings that contain a wide range of organic and inorganic constituents, and provide different ecological. niches that are exploited by a large variety of microbial. species. We isolated and identified the heterotrophic microorganisms found in the biodegraded medieval wall…
Requirement of the Lactobacillus casei MaeKR two-component system for L-malic acid utilization via a malic enzyme pathway.
2009
ABSTRACTLactobacillus caseican metabolizel-malic acid via malolactic enzyme (malolactic fermentation [MLF]) or malic enzyme (ME). Whereas utilization ofl-malic acid via MLF does not support growth, the ME pathway enablesL. caseito grow onl-malic acid. In this work, we have identified in the genomes ofL. caseistrains BL23 and ATCC 334 a cluster consisting of two diverging operons,maePEandmaeKR, encoding a putative malate transporter (maeP), an ME (maeE), and a two-component (TC) system belonging to the citrate family (maeKandmaeR). Homologous clusters were identified inEnterococcus faecalis,Streptococcus agalactiae,Streptococcus pyogenes, andStreptococcus uberis. Our results show that ME is …
Caseicin, a bacteriocin from Lactobacillus casei.
1993
The intracellular bacteriocin caseicin 80 was purified from cell extracts of Lactobacillus casei strain B80. It is a thermolabile protein with an apparent molar mass of 42 kDa. As no plasmids were observed in the bacteriocinogenic strain it is assumed that caseicin is encoded by the bacterial chromosome. Using 14C-labelled precursors it was found that biosynthesis of DNA and proteins was influenced by caseicin but this inhibition is probably not the primary effect. The incorporation of fructose but not of glucose into cellular material was inhibited by caseicin.
Polyphasic study of wine Lactobacillus strains: taxonomic implications
2005
One hundred and seventy-eight lactobacilli isolated from wine were characterized by a polyphasic approach. Strains were phenotypically identified at genus and species level by classical tests including the analysis of cell morphology, homo/heterofermentative character, sugar fermentation patterns, growth at different temperatures and the optical nature of the isomer of lactic acid produced from glucose. Molecular techniques such as random amplification of polymorphic DNA (RAPD), amplified 16S rDNA restriction analysis (16S-ARDRA), PFGE-RFLP and ribotyping were used to characterize strains, and their potential for identification and/or typing was evaluated. The information obtained with thes…