Staphylococcus Research Today is a free monthly online journal that collates and summarizes the latest research about Staphylococcus, including details on mrsa, hospitals, infection, antibiotic resistance, superbugs.

sigmaB activity in a Staphylococcus aureus hemB mutant.

Senn MM, Bischoff M, von Eiff C, Berger-Bächi B

Department of Medical Microbiology, University of Zürich, Gloriastrasse 32, 8006 Zürich, Switzerland.

Inactivation of hemB in Staphylococcus aureus strain Newman resulted in a small-colony phenotype and was accompanied by an altered expression pattern of global regulators and control of virulence factor production. Transcription profiles followed over 15 h by Northern blot analyses revealed that transcripts of the global regulators arl, rot, sae, sarR, sarS, srr, svrA, and sigB disappeared after the exponential phase and that both agr transcripts were completely absent in the hemB mutant. Apart from a general concentration of transcriptional activity to the exponential phase, premature gene expression was observed for rot, hla, and spa. Nevertheless, reported sigmaB-dependent transcripts, such as sarC and clfA, were produced throughout the 15-h growth period monitored. The absence of these transcripts in a hemB sigB double mutant demonstrated their dependence on sigmaB and indicated an unexpected, permanent sigmaB activity in the hemB mutant. Variations in the extents of the directly sigmaB-controlled asp23, rsbVW-sigB, and sarC transcripts argue for additional factors modulating sigmaB activity. This study provides the first extended synopsis of the transcriptional patterns of different regulators over the entire growth cycle in the widely used Newman strain.

Published 20 October 2005 in J Bacteriol, 187(21): 7397-406.
Full-text of this article is available online (may require subscription).

© 2004-2008 Staphylococcus Research Today. All Rights Reserved.