Asian Journal of Bio Science

Tanveer A. Shah ¹, Imtiyaz Murtaza ², V. Verma ³, Arif Ali ¹

Affiliations
1 Gene Expression Laboratory, Department of Biosciences, Jamia Millia Islamia, New Delhi, IN
2 Divison of Post Harvest Technology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Shalimar, Srinagar (J&K), IN
3 S.M.V.D. University, Katra, Jammu (J&K), IN

Abstract

Bacteria (E. coli) isolated from different aquatic bodies of India were analyzed for their tolerance to mercury (HgCl2 ). Out of the 30 isolates of E. coli, collected from water samples of four geographically distinct regions and hospital settings in India, 8 strains showed significantly high levels of tolerance to the inorganic form of mercury i.e mercury chloride (HgCl2). All the eight strains revealed the presence of a plasmid of approximately 24kb, and transformation of the isolated plasmids into the mercury-sensitive competent cells of E. coli DH5 rendered the transformants resistant to the same concentration of mercury as wild type-strains.

Keywords

Escherichia Coli, Mercury Resistance, Mercuric Reductase (merA) Gene.

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Tanveer Ahmad Shah ¹, Arif Ali ²

Affiliations
1 Jammu and Kashmir Entrepreneurship Development Institute, JLN Udhoyg Bhawan, Railhead Complex, Jammu (J&K), IN
2 Gene Expression Laboratory, Department of Biosciences, Jamia Millia Islamia, New Delhi, IN

Abstract

Bacterial plasmids encode resistance systems for toxic metal ions including Hg²⁺ functioning by energy – dependent efflux of toxic ions. The inducible mercury resistance (mer) operon encodes both a mercuric ion uptake and detoxification enzymes. In Gram-negative bacteria especially in E. coli, a periplasmic protein, MerP, an inner-membrane transport protein, MerT, and a cytoplasmic enzyme, mercuric reductase (the merA protein), are responsible for the transport of mercuric ions into cell and their reduction to elemental mercury, Hg°. Phytoremediation involves the use of plants to extract, detoxify and/or sequester environmental pollutants from soil and water. Transgenic plants cleave mercury ions from methyl-mercury complexes; reduce mercury ions to the metallic form; take up metallic mercury through their ischolar_mains; and evolve less toxic elemental mercury. PCR were performed to detect 1695 bp of mercuric reductase gene (merA), which is mainly responsible for the conversion of mercuric (Hg⁺²) and mercurous (Hg⁺¹) ions into non-toxic elemental mercury. PCR products of putative merA genes form environmental E.coli strains were purified and cloned into a suitable plant expression vector like pB1121 or pCAMBIA. The construct will be transformed in calli of Nicotiana plants. Expression of merA gene in transgenic plants might provide an ecologically compatible approach for the remediation of mercury pollution.

Keywords

Mercury Resistance, E. coli, PCR Amplification, Nicotiana.

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Tanveer A. Shah ¹, Arif Ali ¹

Affiliations
1 Gene Expression Laboratory, Department of Biosciences, Jamia Millia Islamia, New Delhi, IN

Abstract

Bacteria (E. coli) isolated from different aquatic bodies of India were analyzed for their tolerance to mercury (HgCl₂). Out of the 30 isolates of E. coli, collected from water samples of four geographically distinct regions and hospital settings in India, 8 strains showed significantly high levels of tolerance to the inorganic form of mercury i.e mercury chloride (HgCl₂). All the eight strains revealed the presence of a plasmid of approximately 24kb, and transformation of the isolated plasmids into the mercury-sensitive competent cells of E. coli DH5α rendered the transformants resistant to the same concentration of mercury as wild type-strains.

Keywords

Escherichia coli, Mercury Resistance, Mercuric Reductase (merA) Gene.

Full Text