Carmen Sánchez-Rivas

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The importance of the content of anionic phospholipids [cardiolipin (CL) and phosphatidylglycerol (PG)] in the osmotic adaptation and in the membrane structure of Bacillus subtilis cultures was investigated. Insertion mutations in the three putative cardiolipin synthase genes (ywiE, ywnE and ywjE) were obtained. Only the ywnE mutation resulted in a complete(More)
The probiotic Gram-positive bacterium Lactobacillus casei BL23 is naturally confronted with salt-stress habitats. It has been previously reported that growth in high-salt medium, containing 0.8 M NaCl, leads to modifications in the cell envelope of this bacterium. In this study, we report that L. casei BL23 has an increased ability to form biofilms and to(More)
AIMS To study the influence of peptides and proteolytic enzymes in the osmotic adaptation of Lactobacillus casei. METHODS AND RESULTS Di- and tri-peptides added individually increased the osmotolerance of Lact. casei when grown in a chemically defined medium (CDM) containing NaCl. Growth stimulation and the re-establishment in their presence of plasmid(More)
Bacillus subtilis cultures submitted to an osmotic upshock (1.5 M NaCl) lysed unless stationary phase had been reached. Several physiological variations were observed, such as delayed growth (adaptation), a filamentous bacterial appearance, RecA-dependent osmoresistance (SOS), and cross-induction by a previous stress (heat shock). Osmoresistance and(More)
The envelope properties of B. subtilis cultures grown in LB and LBN hyperosmotic media (LB + 1.5 M NaCl) were compared. Since hypertonic cultures showed a Spo-phenotype, a Spo-mutant grown in LB was also analyzed. LBN cultures showed extensive filamentation and presented different sensitivities toward phage infection (φ29 and φ105), or antibiotics whose(More)
Bacillus sphaericus, a bacterium of biotechnological interest due to its ability to produce mosquitocidal toxins, is unable to use sugars as carbon source. However, ptsHI genes encoding HPr and EI proteins belonging to a PTS were cloned, sequenced and characterized. Both HPr and EI proteins were fully functional for phosphoenolpyruvate-dependent(More)
AIMS To study the modification of the cell wall of Lactobacillus casei ATCC 393 grown in high salt conditions. METHODS AND RESULTS Differences in the overall structure of cell wall between growth in high salt (MRS + 1 mol l(-1) NaCl; N condition) and control (MRS; C condition) conditions were determined by transmission electronic microscopy and analytical(More)
In previous studies of bacterial protoplast fusion, only the frequencies of cell wall regeneration and of bacterial recombination were determined. In this work the frequency of the heterozygous fusion products is measured by prophage complementation. Two multiply marked nonsuppressing strains of Bacillus subtilis, each lysogenic for a different Sus mutant(More)
Spores of Bacillus subtilis show similar plating efficiency on media with or without 1.5 M NaCl. In contrast, vegetative cells are osmosensitive unless the stationary phase has been reached. In the present work, loss of heat and osmotic resistance during germination was studied. Their kinetics and sensitivity to protein synthesis inhibition were different:(More)
A strain isolated from Argentinean regional fermented sausages was found to produce and secrete a compound that inhibited growth of Lactobacillus strains used as indicators. It was characterized as Paenibacillus polymyxa (P13). The antimicrobial activity, named polyxin, was obtained from culture supernatant fluid of late stationary phase and was inhibitory(More)