0000000000224990
AUTHOR
Aurore Palud
Identification and expression of Lactobacillus paracasei genes for adaptation to desiccation and rehydration
AbstractLactobacillus paracaseiis able to persist in a variety of natural and technological environments despite physico-chemical perturbations, in particular alternations between desiccation and rehydration. However, the way in which it adapts to hydric fluctuations and in particular the genetic determinants involved are not clearly understood. To identify the genes involved in adaptation to desiccation, an annotated library ofL. paracaseirandom transposon mutants was screened for viability after desiccation (25% relative humidity, 25°C). Subsequently, the expression of the identified genes was measured at five stages of the dehydration-rehydration process to formulate the chronology of ge…
Identification and transcriptional profile of Lactobacillus paracasei genes involved in the response to desiccation and rehydration
International audience; Lactobacillus paracasei is able to persist in a variety of natural and technological environments despite physico-chemical perturbations, in particular alternations between desiccation and rehydration. However, the way in which it adapts to hydric fluctuations and the genetic determinants involved are not clearly understood. To identify the genes involved in adaptation to desiccation, an annotated library of L. paracasei random transposon mutants was screened for viability after desiccation (25% relative humidity, 25 °C). We found 16 genes that have not been described as being involved in this response. Most of them are linked to either the transport of molecules or …
Study of the cwaRS-ldcA Operon Coding a Two-Component System and a Putative L,D-Carboxypeptidase in Lactobacillus paracasei
International audience; The cell surface is the primary recognition site between the bacterium and the host. An operon of three genes, LSEI_0219 (cwaR), LSEI_0220 (cwaS), and LSEI_0221 (ldcA), has been previously identified as required for the establishment of Lactobacillus paracasei in the gut. The genes cwaR and cwaS encode a predicted two-component system (TCS) and ldcA a predicted D-alanyl-D-alanine carboxypeptidase which is a peptidoglycan (PG) biosynthesis enzyme. We explored the functionality and the physiological role of these three genes, particularly their impact on the bacterial cell wall architecture and on the bacterial adaptation to environmental perturbations in the gut. The …
New Genes Involved in Mild Stress Response Identified by Transposon Mutagenesis in Lactobacillus paracasei
International audience; Lactic acid bacteria (LAB) are associated with various plant, animal, and human niches and are also present in many fermented foods and beverages. Thus, they are subjected to several stress conditions and have developed advanced response mechanisms to resist, adapt, and grow. This work aimed to identify the genes involved in some stress adaptation mechanisms in LAB. For this purpose, global reverse genetics was applied by screening a library of 1287 Lactobacillus paracasei transposon mutants for mild monofactorial stresses. This library was submitted independently to heat (52 degrees C, 30 min), ethanol (170 g.L-1, 30 min), salt (NaCl 0.8 M, 24 h), acid (pH 4.5, 24 h…