title: Molecular identification of arsenic-resistant estuarine bacteria and characterization of their ars genotype.
abstract: In the present study, 44 arsenic-resistant bacteria were isolated through serial dilutions on agar plate with concentrations ≥0.05 mM of sodium arsenite and ≥10 mM of sodium arsenate from Mandovi and Zuari--estuarine water systems. The ars genotype characterization in 36 bacterial isolates (resistant to 100 mM of sodium arsenate) revealed that only 17 isolates harboured the arsA (ATPase), B (arsenite permease) and C (arsenate reductase) genes on the plasmid DNA. The arsA, B and C genes were individually detected using PCR in 16, 9 and 13 bacterial isolates respectively. Molecular identification of the 17 isolates bearing the ars genotype was carried using 16S rDNA sequencing. A 1300 bp full length arsB gene encoding arsenite efflux pump and a 409 bp fragment of arsC gene coding for arsenate reductase were isolated from the genera Halomonas and Acinetobacter. Phylogenetic analysis of arsB and arsC genes indicated their close genetic relationship with plasmid borne ars genes of E. coli and arsenate reductase of plant origin. The putative arsenate reductase gene isolated from Acinetobacter species complemented arsenate resistance in E. coli WC3110 and JM109 validating its function. This study dealing with isolation of native arsenic-resistant bacteria and characterization of their ars genes might be useful to develop efficient arsenic detoxification strategies for arsenic contaminated aquifers.
authors: Department of Genetics, Osmania University, Hyderabad 500 007, India.
authors: M
authors: M
authors: Sri Lakshmi Sunita
authors: S
authors: S
authors: Prashant
authors: P V
authors: PV
authors: Bramha Chari
authors: S
authors: S
authors: Nageswara Rao
authors: Padma
authors: P
authors: Balaravi
authors: P B
authors: PB
authors: Kavi Kishor
mesh_terms: D001149:Arsenates / Q000032:analysis / Q000378:metabolism; D001151:Arsenic / Q000378:metabolism*; D018053:Arsenites / Q000032:analysis / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D052918:Environmental Restoration and Remediation / Q000379:methods; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D005798:Genes, Bacterial; D005838:Genotype; D016623:Ion Pumps / Q000235:genetics / Q000378:metabolism; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000378:metabolism; D017670:Sodium Compounds / Q000032:analysis / Q000378:metabolism
chemical_list: D001149:Arsenates; D018053:Arsenites; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D016623:Ion Pumps; D009097:Multienzyme Complexes; D012336:RNA, Ribosomal, 16S; D017670:Sodium Compounds; C017947:sodium arsenite; C009277:sodium arsenate; C486481:ArsAB ATPase, E Coli; D001151:Arsenic