title: Characterization of a mercury-reducing Bacillus cereus strain isolated from the Pulicat Lake sediments, south east coast of India.
abstract: Pulicat Lake sediments are often severely polluted with the toxic heavy metal mercury. Several mercury-resistant strains of Bacillus species were isolated from the sediments and all the isolates exhibited broad spectrum resistance (resistance to both organic and inorganic mercuric compounds). Plasmid curing assay showed that all the isolated Bacillus strains carry chromosomally borne mercury resistance. Polymerase chain reaction and southern hybridization analyses using merA and merB3 gene primers/probes showed that five of the isolated Bacillus strains carry sequences similar to known merA and merB3 genes. Results of multiple sequence alignment revealed 99% similarity with merA and merB3 of TnMERI1 (class II transposons). Other mercury resistant Bacillus species lacking homology to these genes were not able to volatilize mercuric chloride, indicating the presence of other modes of resistance to mercuric compounds.
authors.affiliation: Department of Applied Geology, University of Madras, Guindy campus, Post Bag No: 5327, 600 025 Chennai, Tamil Nadu, India. skk2k@rediffmail.com
authors.forename: Seralathan Kamala
authors.initials: SK
authors.lastname: Kannan
authors.forename: Subramony
authors.initials: S
authors.lastname: Mahadevan
authors.forename: Ramaswamy
authors.initials: R
authors.lastname: Krishnamoorthy
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001409:Bacillus cereus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D004251:DNA Transposable Elements; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005618:Fresh Water / Q000382:microbiology*; D019015:Geologic Sediments / Q000382:microbiology*; D007194:India; D008628:Mercury / Q000378:metabolism* / Q000494:pharmacology; D019216:Metals, Heavy / Q000378:metabolism* / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D010088:Oxidoreductases; C021551:mercuric reductase; D008628:Mercury