Article

Redox-Active Antibiotics Control Gene Expression and Community Behavior in Divergent Bacteria

Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 01239, USA.
Science (Impact Factor: 33.61). 09/2008; 321(5893):1203-6. DOI: 10.1126/science.1160619
Source: PubMed

ABSTRACT

It is thought that bacteria excrete redox-active pigments as antibiotics to inhibit competitors. In Pseudomonas aeruginosa, the endogenous antibiotic pyocyanin activates SoxR, a transcription factor conserved in Proteo- and Actinobacteria. In Escherichia coli, SoxR regulates the superoxide stress response. Bioinformatic analysis coupled with gene expression studies in P. aeruginosa and Streptomyces coelicolor revealed that the majority of SoxR regulons in bacteria lack the genes required for stress responses, despite the fact that
many of these organisms still produce redox-active small molecules, which indicates that redox-active pigments play a role
independent of oxidative stress. These compounds had profound effects on the structural organization of colony biofilms in
both P. aeruginosa and S. coelicolor, which shows that “secondary metabolites” play important conserved roles in gene expression and development.

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Available from: Lars E. Dietrich
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    • "One of the roles of SoxS is detoxifying reactive oxygen species such as superoxide and nitric oxide (Dietrich et al., 2008). It has also been reported that the upregulation of SoxS by pyocyanin is restricted to bacteria from the family Enterobacteriaceae (Dietrich et al., 2008), which includes E. coli but not B. subtilis. Similar to pyocyanin, NR may have upregulated SoxS production in E. coli, negating the effects of reactive oxygen species at 0.5 and 5 mM NR. "
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    • "Recently , it has been reported that lpxC belongs to the OxyR reg - ulon in Pseudomonas ( Wei et al . , 2012 ) , but our study showed that it belongs to both SoxR and SoxS in E . coli . In other bacteria , the preserved SoxR tends to control a distinct set of genes involved in redox - active antibiotic production ( Dietrich et al . , 2008 ) . Based on these facts , it might be the case that OxyR ( or another functional ortholog , PerR , when OxyR is not present ; Chiang and Schellhorn , 2012 ) takes over the roles of SoxR and SoxS . Figure 6 . Evolutionary Perspective on OxyR , SoxR , and SoxS Regulons"
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