Toxins MazF and MqsR cleave Escherichia coli rRNA precursors at multiple sites.

The endoribonuclease toxins of the E. coli toxin-antitoxin systems arrest bacterial growth and protein synthesis by targeting cellular mRNAs. As an exception, E.

The effects of disruptions in ribosomal active sites and in intersubunit contacts on ribosomal degradation in Escherichia coli.

Although ribosomes are very stable under most conditions, ribosomal degradation does occur in diverse groups of organisms in response to specific stresses or environmental conditions. While non-functional ribosome decay (NRD) in yeast is well characterized, very little is known of the mechanisms that initiate ribosomal degradation in bacteria. Here we test ribosome degradation in growing Escherichia coli expressing mutant ribosomes.

When stable RNA becomes unstable: the degradation of ribosomes in bacteria and beyond.

This review takes a comparative look at the various scenarios where ribosomes are degraded in bacteria and eukaryotes with emphasis on studies involving Escherichia coli and Saccharomyces cerevisiae. While the molecular mechanisms of degradation in bacteria and yeast appear somewhat different, we argue that the underlying causes of ribosome degradation are remarkably similar. In both model organisms during ribosomal assembly, partially formed pre-ribosomal particles can be degraded by at least two different sequentially-acting quality control pathways and fully assembled but functionally faulty ribosomes can be degraded in a separate quality control pathway.

Ribosome degradation in growing bacteria.

Ribosomes are large ribozymes that synthesize all cellular proteins. As protein synthesis is rate-limiting for bacterial growth and ribosomes can comprise a large portion of the cellular mass, elucidation of ribosomal turnover is important to the understanding of cellular physiology. Although ribosomes are widely believed to be stable in growing cells, this has never been rigorously tested, owing to the lack of a suitable experimental system in commonly used bacterial model organisms.

Expression of heat shock proteins and nitrotyrosine in small arteries from patients with coronary heart disease.

Heat shock proteins (HSPs) have been suggested to play an important role in the pathogenesis of cardiovascular disease; however, their levels in resistance arteries and their role as useful markers for endothelial dysfunction are not well known. In this paper we studied the levels of HSP90, HSP70, HSP60, HSP27, and of the oxidative stress marker nitrotyrosine (NT) in isolated small subcutaneous arteries from female and male patients with coronary heart disease (CHD) and compared them with healthy controls. HSPs and NT levels were analyzed by immunohistochemistry (IHC) with streptavidin-biotin complex and 3,3'-diaminobenzidine (DAB) staining.