Bacteria respond to DNA damage by inducing a coordinated cellular response, governed by the RecA and LexA proteins. Induction of the SOS response modulates the evolution and dissemination of drug resistance, as well as synthesis, secretion and dissemination of virulence factors. This paper presents the structure of the LexA protein, conformations that enable repression of SOS genes via specific DNA binding or repressor cleavage during the response to DNA damage. These may provide new starting points in the battle against the emergence of bacterial pathogens and the spread of drug resistance.
This is a first investigation of virulence factors of E. coli strains isolated from skin and soft tissue. The study revealed that the investigated strains exhibited a virulence potential comparable to that of E. coli isolates from urinary tract infection and bacteremia.
Growth media for cultivation of halophilic archaea was optimized using surface responsive methodoloy and modelling. Growth was faster and cell density was significantly higher.
Many of the genes that differ between strains affect regions that are potential phage recognition targets. We therefore propose the constant-diversity dynamics model, in which the diversity of prokaryotic populations is preserved by phage predation. We provide supporting evidence for this model from metagenomics, mathematical analysis and computer simulations.
In this study, the diversity of prokaryotes inhabiting crystallizer ponds of three solar salterns, located along Bengal Bay in Tamil Nadu, India was examined. Representatives of the family Halobacteriaceae dominated with members of genera Haloferax, Halorubrum, Haloarcula, Halobacterium and Halogeometricum recovered in pure culture. In contrast, members of Bacteria were recovered from only one sampling site and were represented by members of genera Salinibacter, Cytophaga and Marinococcus. The predominant members of the haloarchaeal crystallizer community belonged to the genus Natrinema.