Applied Cell Biology

Rising to the challenge: Role of stress responses andmolecular chaperones in bacteria

Ciamak Ghazaei

Department of Microbiology, University of Mohaghegh Ardabili, Ardabil, P.O. Box 179, (IRAN)

Abstract

The survival of bacteria, in their often unfavourable and frequently changing immediate environment, is enabled mainly by two factors: the bacterial stress responses and the bacterial molecular chaperones. This review article comprehensively explores the most significant bacterial stress response systems known so far and the part played by and the workingmechanism of the bacterial chaperones in ensuring the survival of the bacteria in their immediate surroundings. The principal bacterial stress response systems explored in this review include: heat shock response (which is governed by Sigma 32 factor), pppGpp-dependent strict response (which decreases the synthesis of cellular proteins), cold shock response (which controls the expression of ribosomal and RNA chaperones factors), engulf stress response (which is controlled by sigma factor E) and the general stress response  (which depends on sigma S factor). On the other hand, the paper explores the bacterial molecular chaperones as the bacteria’s dynamic evasive mechanism of protecting themselves in adverse environment, for instance within the host organism, and thus  ontrolling the entire infection process To this effect, the review focuses on the bacteria’s response to a number of stressful  environments, examples of bacteria that are well adapted to the intracellular environment within macrophages (this is considered  to be the most stressful environment for bacteria) and finally, the various bacterial molecular chaperones and the role they play in  the survival of the pathogenic bacteria within the host.

Keywords:

Bacteria; Environment; Chaperones; Molecular chaperones; Stress response.