Protective Roles of Bacterioruberin and Intracellular KCl in the Resistance of Halobacterium salinarium against DNA-damaging Agents

Hamid Reza Shahmohammadi, Ezat Asgarani, Hiroaki Terato, Takeshi Saito, Yoshihiko Ohyama, Kunihiko Gekko, Osamu Yamamoto, Hiroshi Ide

Research output: Contribution to journalArticlepeer-review

82 Citations (Scopus)

Abstract

Halobacterium salinarium, a member of the extremely halophilic archaebacteria, contains a C50-carotenoid namely bacterioruberin. We have previously reported the high resistance of this organism against the lethal 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.

Original languageEnglish
Pages (from-to)251-262
Number of pages12
JournalJournal of radiation research
Volume39
Issue number4
DOIs
Publication statusPublished - Dec 1998
Externally publishedYes

Keywords

  • Bacterioruberin
  • DNA-damage
  • Halobacterium salinarium
  • Radiation
  • Salt effect

ASJC Scopus subject areas

  • Radiation
  • Radiology Nuclear Medicine and imaging
  • Health, Toxicology and Mutagenesis

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