关键词: 耐辐射奇球菌 光敏色素 光损伤 氧感受器

Abstract:

With the method of polymerase chain reaction and homologous genetic recombination in vivo, the gene encoding bacterial phytochrome in the non-photosynthetic and extremely radioresistant bacterium D.radiodurans was deleted from the genome. Survival rates of the mutant strain bphP^- obtained and wild type strain were investigated under different doses of T-radiation and hydrogen peroxide. The results indicated that the bphF strain were much more sensitive to hydrogen peroxide treatment comparing to that of wild type R1, while radioresistant activities of the mutant and the R1 strain exhibited at the same level. Experiments of D.radiodurans R1 strain to different light radiation revealed that intense white light radiation remarkably inhibited both the colony growth of wild-type and the phytochrome function-deficient mutant of D. radiodurans with no significant difference, while the growth of Escherichia coli K 12 was not affected under the same light condition. No remarkable effects of red and blue light on the growth of D.radiodurans strain were shown. Based on these results, phytochrome in D.radiodurans might primarily act as a signal transferrer and regulator of oxidant pressure.

Key words: Deinococcus radiodurans, phytochrome, light-inducing damage, oxygen sensor