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Environmental Informatics Archives
ISSN 1811-0231 / ISEIS Publication Series Number P002
Copyright © 2007 ISEIS. All rights reserved.
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Paper EIA07-072, Volume 5 (2007), Pages 690-693 = complimentary
Selenium Induced Reduction of Pyrene Toxicity in Bacteria
S. S. Yadav1, M. K. Garg1, R. Prakash2 and T. Prakash1*
1. Department of Biotechnology and Environmental Sciences. *Corresponding author: .
2. School of Chemistry and Biochemistry, Thapar University, Thapar Technology Campus, Patiala 147004, India.
Abstract
Selenium can provoke contrasting effect on living organisms. It is an essential trace element and low concentrations have beneficial effect and provide protection against compounds causing oxidative damage like pesticides, however higher concentrations of selenium salts can be toxic and mutagenic. Bacterial isolate S- 60 which was selenium tolerant, therefore when challenged with pyrene in presence and absence of selenium showed better survival i.e more cfu count in presence of selenium particularly at 20 ppm selenium, instead of in the absence of selenium. Same results were obtained when bacterial isolate S-60 challenged with chlorpyrifos. These observations suggest that selenium plays protective role against pesticidal stress. Previous research was carried out to study defence mechanism developed similar to oxidative stress in microbes exposed to pesticides and organic hydrocarbons. It was found that the SOD protein was constitutive in isolate S-60. Growth pattern studies when carried out in basal media with and without stress, It was observed that there was rapid enhancement in SOD activity on minimal media with stress conditions, particularly in extracellular fraction. This indicates that in the presence of, pyrene and chlorpyrifos the cells generated oxy-intermediates and this leads to the increase in SOD activity if the organism is prior exposed to selenium. The study attempts to demonstrate the role of selenium in reducing the toxicity of organic contaminants.
Keywords: selenium, pesticide, toxicity, bacteria, protection