Cell-Wide Responses to Low-Oxygen Exposure in<i>Desulfovibrio vulgaris</i>Hildenborough

ABSTRACT The responses of the anaerobic, sulfate-reducing organism Desulfovibrio vulgaris Hildenborough to low-oxygen exposure (0.1% O 2 ) were monitored via transcriptomics and proteomics. Exposure to 0.1% O 2 caused a decrease in the growth rate without affecting viability. Concerted upregulation of the predicted peroxide stress response regulon (PerR) genes was observed in response to the 0.1% O 2 exposure. Several of the candidates also showed increases in protein abundance. Among the remaining small number of transcript changes was the upregulation of the predicted transmembrane tetraheme cytochrome c 3 complex. Other known oxidative stress response candidates remained unchanged during the low-O 2 exposure. To fully understand the results of the 0.1% O 2 exposure, transcriptomics and proteomics data were collected for exposure to air using a similar experimental protocol. In contrast to the 0.1% O 2 exposure, air exposure was detrimental to both the growth rate and viability and caused dramatic changes at both the transcriptome and proteome levels. Interestingly, the transcripts of the predicted PerR regulon genes were downregulated during air exposure. Our results highlight the differences in the cell-wide responses to low and high O 2 levels in D. vulgaris and suggest that while exposure to air is highly detrimental to D. vulgaris , this bacterium can successfully cope with periodic exposure to low O 2 levels in its environment.