Characterization of a stress tolerance ‐defective mutant of Lactobacillus rhamnosus LRB

In this study we usedL.  rhamnosus LRB to isolate one spontaneous mutant that was sensitive to acid stress. The mutant, which we named RBM1, also displayed sensitivity to a wide range of stresses including osmotic, thermal, and others. Using whole genome sequencing, we mapped the putative mutations in the mutant strain. It appears that three single nucleotide substitutions occurred in the mutant as compared to the wild ‐type LRB strain. Among those, the most relevant mutation occurred in theftsH gene that created a single amino acid change in the protein. We performed a comparative proteomic study to understand the molecular basis for stress sensitivity and found that ~15% of the proteome is altered in the mutant strain. Our study suggests that generation of spontaneous mutants duringL.  rhamnosus colonization could drastically affect bacterial physiology and survival under stress conditions.
Source: Molecular Oral Microbiology - Category: Microbiology Authors: Tags: ORIGINAL ARTICLE Source Type: research