Affiliation:
1. Department of Microbiology, Cornell University, Ithaca, New York 14853
2. Department of Environmental and Biomolecular Systems, Oregon Graduate Institute School of Science and Engineering, Oregon Health & Science University, Beaverton, Oregon 97006
3. Experimental Station E328/148B, DuPont Central Research and Development, Wilmington, Delaware 19880
Abstract
ABSTRACT
We examined the effects of nitric oxide (NO) and sodium nitroprusside (SNP) on
Bacillus subtilis
physiology and gene expression. In aerobically growing cultures, cell death was most pronounced when NO gas was added incrementally rather than as a single bolus, suggesting that the length of exposure was important in determining cell survival. DNA microarrays, Northern hybridizations, and RNA slot blot analyses were employed to characterize the global transcriptional response of
B. subtilis
to NO and SNP. Under both aerobic and anaerobic conditions the gene most highly induced by NO was
hmp
, a flavohemoglobin known to protect bacteria from NO stress. Anaerobically, NO also induced genes repressed by the Fe(II)-containing metalloregulators, Fur and PerR, consistent with the known ability of NO to nitrosylate the Fe(II) center in Fur. In support of this model, we demonstrate that NO fails to induce PerR-regulated genes under growth conditions that favor the formation of PerR:Mn(II) rather than PerR:Fe(II). Aerobically, NO gas induced
hmp
, the σ
B
general stress regulon, and, to a lesser extent, the Fur and PerR regulons. Surprisingly, NO gas induced the σ
B
regulon via the energy branch of the σ
B
regulatory cascade while induction by SNP was mediated by the environmental stress branch. This emphasizes that NO and SNP elicit genetically distinct stress responses.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
125 articles.
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