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Mechanism of plasmid encoded mercury volatilization in Acinetobacter junii ACN4.
388
Abstracts
FOll
MECHANISM OF PLASMID ENCODED MERCURY VOLATILIZATION IN ACINETOBACTER JUNII
ACNI.
b and S.B.Padhyeb A.S.Kumbhar, P.K.Dhakephalkar,a B.A.Chopadea b Chemistry, University Departments of aMicrobiology and of Poona, Pune-411007. India. river Acinetobacter junii ACN4 was isolated from and resistant to multiple metals water, as a bacterium 78 kb plasmid ACN4 contained a single antibiotics. broad spectrum pup1102 which encoded designated as chloride resistance to mercurial compounds such as mercuric (200 yg/ml), fluoresceine mercuric acetate (250 Mg/ml), (150 merbromin acetate (150 pg/ml) and to mercuric gentamycin, also encoded resistance to jag/ml) .pUPI102 neomycin and to tetracycline. volatilization studies [l] revealed Qualitative mechanism that volatilization of mercuric chloride was the of pUPI encoded mercury resistance in ACNI. The plasmid pup1102 also mediated volatilization of organomercurials in Quantitative ACN4 but less efficiently than that of HgC12. ACN4 mercury that volatilized estimation of revealed 91.175% of mercury when grown at 37OC in presence of HgC12 (100 pg/ml) for 24 h. Traces of mercury were estimated intracellularly in ACN4 while no traces of mercury could be estimated extracellularly. This shows that volatilization of bound intracellular process and membrane mercury is an into proteins offered no resistance to the entry of mercury the cells. Also volatilization is the mechanism of mercury resistance rather than conversion of mercury into nontoxic form such as sulfide. Cloning of restriction fragments into vector pUC18 [2] located mer gene on 12.2 kb BamHI fragment of pUPI102. The mer gene encoded synthesis of two enzymes; 1) mercuric reductase, which converts Hg2+ into Hg', which is nontoxic to the cell and due to it's high vapour pressure volatilises rapidly, and 2) organomercurial lyase which breaks the C-H bond in organomercurials and releases Hg2+. The pup1102 encoded mercuric reductase was of protoype type I. This is the first rport on plasmid encoded broad spectrum mercury resistance and it's mechanism in Acinetobacter. l] K.Nakamura, H.Nakahara, Appl.Environ.Microbiol., 54, 2871 (1988) 21 T.Maniatis, E.F.Fritsch, J.Sambrook, Molecular Cloning : A laboratory manual., Cold Spring Harbour Laboratory Press.New York.
Abstracts
FOll
MECHANISM OF PLASMID ENCODED MERCURY VOLATILIZATION IN ACINETOBACTER JUNII
ACNI.
b and S.B.Padhyeb A.S.Kumbhar, P.K.Dhakephalkar,a B.A.Chopadea b Chemistry, University Departments of aMicrobiology and of Poona, Pune-411007. India. river Acinetobacter junii ACN4 was isolated from and resistant to multiple metals water, as a bacterium 78 kb plasmid ACN4 contained a single antibiotics. broad spectrum pup1102 which encoded designated as chloride resistance to mercurial compounds such as mercuric (200 yg/ml), fluoresceine mercuric acetate (250 Mg/ml), (150 merbromin acetate (150 pg/ml) and to mercuric gentamycin, also encoded resistance to jag/ml) .pUPI102 neomycin and to tetracycline. volatilization studies [l] revealed Qualitative mechanism that volatilization of mercuric chloride was the of pUPI encoded mercury resistance in ACNI. The plasmid pup1102 also mediated volatilization of organomercurials in Quantitative ACN4 but less efficiently than that of HgC12. ACN4 mercury that volatilized estimation of revealed 91.175% of mercury when grown at 37OC in presence of HgC12 (100 pg/ml) for 24 h. Traces of mercury were estimated intracellularly in ACN4 while no traces of mercury could be estimated extracellularly. This shows that volatilization of bound intracellular process and membrane mercury is an into proteins offered no resistance to the entry of mercury the cells. Also volatilization is the mechanism of mercury resistance rather than conversion of mercury into nontoxic form such as sulfide. Cloning of restriction fragments into vector pUC18 [2] located mer gene on 12.2 kb BamHI fragment of pUPI102. The mer gene encoded synthesis of two enzymes; 1) mercuric reductase, which converts Hg2+ into Hg', which is nontoxic to the cell and due to it's high vapour pressure volatilises rapidly, and 2) organomercurial lyase which breaks the C-H bond in organomercurials and releases Hg2+. The pup1102 encoded mercuric reductase was of protoype type I. This is the first rport on plasmid encoded broad spectrum mercury resistance and it's mechanism in Acinetobacter. l] K.Nakamura, H.Nakahara, Appl.Environ.Microbiol., 54, 2871 (1988) 21 T.Maniatis, E.F.Fritsch, J.Sambrook, Molecular Cloning : A laboratory manual., Cold Spring Harbour Laboratory Press.New York.