Global Gene Expression Analysis of Bacterial Stress Response to Elevated Concentrations of Toxic Metalloids—Selenium and Arsenic

In our earlier study, a bacterial isolate, Bacillus cereus (strain CM100B) was reported to detoxify selenite oxyions with concomitant generation of amorphous selenium (Se0) nanospheres. A whole genome transcriptional analysis was performed to study the genome wide stress response of this bacterium to elevated concentrations of selenite and arsenite oxyions. Data analysis revealed that various genes related to metabolic pathways, transcription, DNA repair and replication and oxidative stress were activated symptomatic of the various stress related response. It seems that in order to cope with the oxidative stress that results from the exposure to oxidants such as selenite and arsenite, bacteria have evolved multiple, and often redundant, defense systems to eliminate the reactive oxyion species (ROS) from the cell.