SIGNAL RESPONSE BETWEEN NITRIC OXIDE SYNTHASE AND METALLOTHIONEIN IN CHROMIUM AND LEAD TREATED BACTERIA ISOLATED FROM COAL MINE AREA

Abstract

In the study an attempt was made to reveal signal cross talk between metallothionein (MT) and Nitric Oxide Synthase (NOS) in the bacteria isolated from soil of Raniganj Coal mine area after treatment of bacteria with Chromium (Cr) and Lead (Pb). Cr(VI) reducing ability of the bacteria and hence its metal remediation was studied by the Chromate reductase activity of the bacteria. Lead bioremediation was assayed by the Atomic absorption spectroscopy (AAS) after treatment of bacteria with Pb(II). MT was extracted from bacteria isolated from coal mine area. Induction of protein like MT having molecular weight 14 kD occurs in isolated bacteria upon treatment with heavy metals like Cr(VI) and Pb(II) as evidenced from SDS PAGE. The thiol content in metal treated bacteria increased in comparison with the control (metal untreated bacteria). Metals induce NOS activity when it is compared to the control. NOS binds transition metals and demonstrates increment in expression of NOS activity in presence of metals like Cr(VI) and Pb(II). In this study, the effects of these heavy metals on the activity of NOS and the effects of NOS on the thiol content of proteins have been discussed. The mechanism of action of xenobiotics like Pb and trace metals like Cr are to some extent different in terms of thiol content and NOS activity. A hypothesis regarding the relationship between MT and NOS has been proposed here. Bacteria where MT synthesis is regulated by NOS can be used in sites contaminated with higher concentrations of heavy metals.