Deinococcus indicus sp. nov., an arsenic-resistant bacterium from an aquifer in West Bengal, India

1 Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India 2 Geological Survey of India, GSI Complex, DK-6, Sector-II, Bidhannagar, Kolkata 700 091, India Correspondence S. Shivaji shivas{at}ccmb.res.in An arsenic- and radiation-resistant bacterium, strain Wt/1a T , was isolated from water from an arsenic-contaminated aquifer located in the Chakdah district of West Bengal, India. The bacterium stains Gram-negative and is rod-shaped, non-motile, non-sporulating and red-pigmented. Cell-wall peptidoglycan contains ornithine as the diamino acid, MK-8 is the major menaquinone, C 15 : 1 and C 16 : 1 are the major fatty acids and the DNA G+C content of the organism is 65·8 mol%. Based on these phenotypic and chemotaxonomic characteristics, strain Wt/1a T was identified as a member of the genus Deinococcus . Strain Wt/1a T exhibited maximum 16S rRNA gene sequence similarity (95 %) with Deinococcus grandis ; however, strain Wt/1a T exhibited only 14 % similarity to D. grandis IAM 13005 T at the DNA–DNA level. Furthermore, strain Wt/1a T (compared to D. grandis IAM 13005 T ) is more resistant to arsenate and arsenite, is positive for arginine dihydrolase, utilizes a number of carbon sources and exhibits quantitative differences in fatty acid composition and qualitative differences in lipid composition. Strain Wt/1a T is identified as a novel species of the genus Deinococcus , for which the name Deinococcus indicus sp. nov. is proposed. The type strain of Deinococcus indicus is Wt/1a T (=MTCC 4913 T =DSM 15307 T ). Abbreviations: DPG, diphosphatidylglycerol; PC, phosphatidylcholine; PG, phosphatidylglycerol; PI, phosphatidylinositol Published online ahead of print on 12 September 2003 as DOI 10.1099/ijs.0.02758-0. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain Wt/1a T is AJ549111 . A table showing survival of Deinococcus species under UV light and a figure showing one-dimensional TLC of total lipid extracts from Deinococcus species are available as supplementary material in IJSEM Online.