Hydrogen peroxide-induced oxidative stress responses in Desulfovibrio vulgaris Hildenborough

摘要

To understand how sulphate-reducing bacteria respond to oxidative stresses, the responses of Desulfovibrio vulgaris Hildenborough to H_2O_2-induced stresses were investigated with transcriptomic, proteomic and genetic approaches. H_2O_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_2O_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_2O_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_2O_2-induced stresses. In addition, a conceptual cellular model of D. vulgaris responses to H_2O_2 stress was constructed to illustrate that this bacterium may employ a complicated molecular mechanism to defend against the H_2O_2-induced stresses.