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标题：Protective Roles of Bacterioruberin and Intracellular KCl in the Resistance of Halobacterium salinarium against DNA-damaging Agents.
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作者：HAMID REZA SHAHMOHAMMADI ; EZAT ASGARANI ; HIROAKI TERATO 等
期刊名称：Journal of Radiation Research
印刷版ISSN：0449-3060
电子版ISSN：1349-9157
出版年度：1998
卷号：39
期号：4
页码：251-262
DOI：10.1269/jrr.39.251
摘要：Halobacteriumm salinarium , a member of the extremely halophilic archaebacteria, contains a C 50 -carotenoid namely bacterioruberin. We have previously reported the high resistance of this organism against thelethal actions of DNA-damaging agents including ionizing radiation and ultraviolet light (UV). In this study, we have examined whether bacterioruberin and the highly concentrated salts in this bacterium play protective roles against the lethal actions of ionizing radiation, UV, hydrogen peroxide, and mitomycin-C (MMC). The colourless mutant of H. salinarium deficient in bacterioruberin was more sensitive than the red-pigmented wild-type to all tested DNA-damaging agents except MMC. Circular dichroism (CD) spectra of H. salinarium chromosomal DNA at various concentrations of KCl (0-3.5 M) were similar to that of B-DNA, indicating that no conformational changes occurred as a result of high salt concentrations. However, DNA strand-breaks induced by ionizing radiation were significantly reduced by the presence of either bacterioruberin or concentrated KCl, presumably due to scavenging of free radicals. These results suggest that bacterioruberin and intracellular KCl of H. salinarium protect this organism against the lethal effects of oxidative DNA-damaging agents.
关键词：Halobacterium salinarium;Bacterioruberin;Salt effect;Radiation;DNA-damage