Updated project metadata. In this study, the effect of nitroprusside on protein expression of the model sulfate reducing bacterial isolate (Desulfovibrio vulgaris Hildenborough) was investigated. Three different experiments were done with different exposure time to nitroprusside (30 min, 1 hour, and 3 hours). In each experiment, the culture was grown in quadruplet of serum bottles containing 40 ml complex medium (Postgate medium B) under anaerobic condition at 30oC. At mid-log growth phase, each of the quadruplet culture was divided into two (20 ml each) and nitroprusside (0.25 mM) was added to one of each bottle while the other bottles were used as controls. After 30 min, 1 hour, and 3 hours of exposure to nitroprusside, the culture (1 ml) was pelleted and used for proteomic analysis.