Metabolome and transcriptome-wide effects of the carbon storage regulator A in enteropathogenic Escherichia coli.

The carbon storage regulator A (CsrA) is a conserved global regulatory system known to control central carbon pathways, biofilm formation, motility, and pathogenicity. The aim of this study was to characterize changes in major metabolic pathways induced by CsrA in human enteropathogenic Escherichia coli (EPEC) grown under virulence factor-inducing conditions. For this purpose, the metabolomes and transcriptomes of EPEC and an isogenic ∆csrA mutant derivative were analyzed by untargeted mass spectrometry and RNA sequencing, respectively.

Mutations targeting the plug-domain of the Shewanella oneidensis proton-driven stator allow swimming at increased viscosity and under anaerobic conditions.

Shewanella oneidensis MR-1 possesses two different stator units to drive flagellar rotation, the Na -dependent PomAB stator and the H -driven MotAB stator, the latter possibly acquired by lateral gene transfer. Although either stator can independently drive swimming through liquid, MotAB-driven motors cannot support efficient motility in structured environments or swimming under anaerobic conditions. Using ΔpomAB cells we isolated spontaneous mutants able to move through soft agar.