title: Multiple-stress tolerance of ionizing radiation-resistant bacterial isolates obtained from various habitats: correlation between stresses.
abstract: Isolation of five ionizing radiation (IR)-resistant bacteria by screening of isolates from various habitats classified as common and stressed is reported. IR-resistant isolates exhibited varying degrees of resistance to gamma-radiation and were classified as highly and moderately radiation resistant. Resistance to ultraviolet (UV) radiation correlated well with gamma-radiation resistance, whereas a comparable desiccation resistance for all the highly and moderately radiation-resistant isolates was observed. However, salt tolerance failed to correlate with IR resistance, indicating a divergent evolution of the salt tolerance and radiation resistance. Characterization of isolates by the amplified rDNA restriction analysis profiling attested to the clustering of these isolates with their stress phenotype. 16S rRNA gene-based analysis of the isolates showed that the bacteria with similar-resistance physiologies clustered together and belonged to related genera. Hydrogen peroxide resistance and mitomycin survival patterns of the isolates indicated the roles of oxidative-stress tolerance in desiccation survival and recombination repair in higher radiation resistance, respectively.
authors.affiliation: Department of Microbiology, M.S. University of Baroda, Vadodara, 390 002, India.
authors.forename: Manish
authors.initials: M
authors.lastname: Shukla
authors.forename: Ruchi
authors.initials: R
authors.lastname: Chaturvedi
authors.forename: Dhruti
authors.initials: D
authors.lastname: Tamhane
authors.forename: Pranav
authors.initials: P
authors.lastname: Vyas
authors.forename: G
authors.initials: G
authors.lastname: Archana
authors.forename: Shree
authors.initials: S
authors.lastname: Apte
authors.forename: J
authors.initials: J
authors.lastname: Bandekar
authors.forename: Anjana
authors.initials: A
authors.lastname: Desai
mesh_terms: D004269:DNA, Bacterial / Q000032:analysis; D034301:Deinococcus / Q000145:classification / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D017753:Ecosystem; D005720:Gamma Rays; D006095:Gram-Positive Cocci / Q000145:classification / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects*; D018869:Heat-Shock Response; D008835:Micrococcaceae / Q000145:classification / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D011836:Radiation Tolerance; D011839:Radiation, Ionizing; D015183:Restriction Mapping; D012240:Rhodococcus / Q000145:classification / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D012988:Soil Microbiology; D014466:Ultraviolet Rays
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S