Hydrogen peroxide-induced oxidative stress responses in Desulfovibrio vulgaris Hildenborough

Abstract

To understand how sulphate-reducing bacteria respond to oxidative stresses, the responses of Desulfovibrio vulgaris Hildenborough to H(2)O(2)-induced stresses were investigated with transcriptomic, proteomic and genetic approaches. H(2)O(2) and induced chemical species (e.g. polysulfide, ROS) and redox potential shift increased the expressions of the genes involved in detoxification, thioredoxin-dependent reduction system, protein and DNA repair, and decreased those involved in sulfate reduction, lactate oxidation and protein synthesis. A gene coexpression network analysis revealed complicated network interactions among differentially expressed genes, and suggested possible importance of several hypothetical genes in H(2)O(2) stress. Also, most of the genes in PerR and Fur regulons were highly induced, and the abundance of a Fur regulon protein increased. Mutant analysis suggested that PerR and Fur are functionally overlapped in response to stresses induced by H(2)O(2) and reaction products, and the upregulation of thioredoxin-dependent reduction genes was independent of PerR or Fur. It appears that induction of those stress response genes could contribute to the increased resistance of deletion mutants to H(2)O(2)-induced stresses. In addition, a conceptual cellular model of D. vulgaris responses to H(2)O(2) stress was constructed to illustrate that this bacterium may employ a complicated molecular mechanism to defend against the H(2)O(2)-induced stresses.