Publication

Abstract : Bacteria respond to xenobiotics in their immediate environment and can either tolerate/ evade high concentrations of it, or are capable of their removal through degradation. A highly efficient and rapid chlorpyrifos (CP) degrader Pseudomonas nitroreducens AR-3 was previously reported, and the current work focused on elucidating the molecular mechanisms by which the bacterium achieves this. The bacterial response to CP included remodelling of the proteome and induction of global response pathways. Sixty-four out of the 794 significantly up-regulated proteins were specifically involved in carbohydrate metabolism, environmental and genetic information processing, biosynthesis of secondary metabolites and metabolism in diverse environments. There was an induction of (mainly) periplasmic proteins, and those involved in chemical degradation pathways. Interestingly, an unprecedented repression of stress responsive pathways and xenobiotic transporter elements were also observed, presumably due to the non-recognition of CP as a stress factor. A presumptive MBL-fold metallo-hydrolase protein showing 44% sequence similarity to an organophosphate hydrolase (ophC2) was identified from the genome. Understanding of the dynamic changes in the protein profiles shed light into the basic cellular and molecular mechanisms underlying CP degradation and enabling the organism to sustain under adverse conditions.