title: Characterization of arsenite tolerant Halomonas sp. Alang-4, originated from heavy metal polluted shore of Gulf of Cambay.
abstract: Arsenite [As(III)]-oxidizing bacteria were isolated from heavy metal contaminated shore of Gulf of Cambay at Alang, India. The most efficient bacterial strain Alang-4 could tolerate up to 15 mM arsenite [As(III)] and 200 mM of arsenate [As(V)]. Its 16S rRNA gene sequence was 99% identical to the 16S rRNA genes of genus Halomonas (Accession no. HQ659187). Arsenite oxidase enzyme localized on membrane helped in conversion of As(III) to As(V). Arsenite transporter genes (arsB, acr3(1) and acr3(2)) assisted in extrusion of arsenite from Halomonas sp. Alang-4. Generation of ROS in response to arsenite stress was alleviated by higher activities of catalase, ascorbate peroxidase, superoxide dismutase and glutathione S-transferase enzymes. Down-regulation in the specific activities of nearly all dehydrogenases of carbon assimilatory pathway viz., glucose-6-phosphate, pyruvate, α-ketoglutarate, isocitrate and malate dehydrogenases, was observed in presence of As(III), whereas, the specific activities of phosphoenol pyruvate carboxylase, pyruvate carboxylase and isocitrate lyase enzymes were found to increase two times in As(III) treated cells. The results suggest that in addition to efficient ars operon, alternative pathways of carbon utilization exist in the marine bacterium Halomonas sp. Alang-4 to overcome the toxic effects of arsenite on its dehydrogenase enzymes.
authors: a Department of Plant Molecular Biology and Biotechnology , ASPEE College of Horticulture and Forestry, Navsari Agricultural University , Navsari , Gujarat , India.
authors: Raina
authors: R
authors: Jain
authors: b Gujarat Agricultural Biotechnology Institute, Navsari Agricultural University , Surat , Gujarat , India.
authors: Sanjay
authors: S
authors: Jha
authors: c Directorate of Groundnut Research , Junagadh , Gujarat , India.
authors: Mahesh K
authors: MK
authors: Mahatma
authors: d Department of Biotechnology , Ashok & Rita Patel Institute of Integrated Study & Research in Biotechnology & Allied Sciences , New Vidyanagar , Gujarat , India.
authors: Anamika
authors: A
authors: Jha
authors: e Department of Biochemistry , Faculty of Science, The Maharaja Sayajirao University of Baroda , Vadodara , Gujarat , India.
authors: G Naresh
authors: GN
authors: Kumar
mesh_terms: D053502:Arsenate Reductases / Q000235:genetics / Q000378:metabolism*; D018053:Arsenites / Q000378:metabolism*; D004784:Environmental Monitoring; D020632:Halomonas / Q000737:chemistry* / Q000235:genetics; D007194:India; D019216:Metals, Heavy / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D012623:Seawater / Q000737:chemistry* / Q000382:microbiology*
chemical_list: D018053:Arsenites; D019216:Metals, Heavy; D010088:Oxidoreductases; D053502:Arsenate Reductases
keywords: Arsenite; Halomonas; antioxidant enzymes; ars operon; citric acid cycle