title: Isolation and characterization of a novel gamma-radiation-resistant bacterium from hot spring in Iran.
abstract: 30 pure colonies with various colors and shapes were isolated from the samples of water and mud which were collected from the Abe-Siah hot springs in Ramsar, a city in north of Iran, with high-level of radiation (up to 4 Gy). Colonies were irradiated by 22 KGy radiations and only one of them survived. The survived bacterium with an optimum growth of 30 to 37 degrees C, pH 6 to 7, and at minimum of 5% NaCl concentration showed promising characteristics. This strain is aerobic, mesophilic, white colony, with catalase-positive, oxidase-negative, non motile, spore forming, rod-shape and finally Gram positive. Strain Bacillus sp. WHO represented a strain of genus Bacillus megaterium according to a phylogenetic analysis of the 16S rDNA and biochemical features. Its radio-resistancy was compared with E. coli and B. megaterium which were inactivated in 2 KGy and 5.9 KGy respectively. In order to reveal the mechanisms of this extreme radio-resistancy and WHO DNA repair system we examined its proteomic map, following gamma-irradiation, using two-dimensional polyacrylamide gel electrophoresis and silver-staining. The expression levels of majority number of protein spots showed significant changes under radiation stress.
authors.affiliation: Department of Biochemistry, Faculty of Science, Tarbiat Modares University, Tehran, Iran.
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Yazdani
authors.forename: Hossein
authors.initials: H
authors.lastname: Naderi-Manesh
authors.forename: Khosro
authors.initials: K
authors.lastname: Khajeh
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Soudi
authors.forename: S Mohsen
authors.initials: SM
authors.lastname: Asghari
authors.forename: Marziyeh
authors.initials: M
authors.lastname: Sharifzadeh
mesh_terms: D001407:Bacillus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D004275:DNA, Ribosomal / Q000235:genetics; D015180:Electrophoresis, Gel, Two-Dimensional; D005720:Gamma Rays; D045482:Hot Springs / Q000382:microbiology*; D007492:Iran; D050296:Microbial Viability; D010802:Phylogeny; D020543:Proteome / Q000378:metabolism; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014871:Water Microbiology
chemical_list: D004275:DNA, Ribosomal; D020543:Proteome; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S