Nag Sagorika, DasSarma Priya, Crowley David J, Hamawi Rafael, Tepper Samantha, Anton Brian P, Guzmán Daniel, DasSarma Shiladitya
Blue Marble Space Institute of Science, Seattle, WA 98104, USA.
Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Microorganisms. 2023 Feb 28;11(3):607. doi: 10.3390/microorganisms11030607.
Ultraviolet (UV) radiation responses of extremophilic and archaeal microorganisms are of interest from evolutionary, physiological, and astrobiological perspectives. Previous studies determined that the halophilic archaeon, sp. NRC-1, which survives in multiple extremes, is highly tolerant of UV radiation. Here, sp. NRC-1 UV tolerance was compared to taxonomically diverse Haloarchaea isolated from high-elevation salt flats, surface warm and cold hypersaline lakes, and subsurface Permian halite deposits. / spp. from subsurface halite deposits were the least tolerant after exposure to photoreactivating light. This finding was attributed to deviation of amino acid residues in key positions in the DNA photolyase enzyme or to the complete absence of the photolyase gene. Several and species from surface environments exposed to high solar irradiance were found to be the most UV tolerant, and from lake sediment was of intermediate character. These results indicate that high UV tolerance is not a uniform character trait of Haloarchaea and is likely reflective of UV exposure experienced in their environment. This is the first report correlating natural UV tolerance to photolyase gene functionality among Haloarchaea and provides insights into their survival in ancient halite deposits and potentially on the surface of Mars.
从进化、生理和天体生物学的角度来看，极端嗜盐古生菌和嗜盐微生物对紫外线（UV）的反应备受关注。先前的研究表明，能在多种极端环境中生存的嗜盐古生菌NRC-1菌株对紫外线具有高度耐受性。在此，将NRC-1菌株的紫外线耐受性与从高海拔盐沼、地表温暖和寒冷的高盐湖泊以及地下二叠纪岩盐矿床中分离出的分类学上不同的嗜盐古菌进行了比较。暴露于光复活光后，来自地下岩盐矿床的菌株耐受性最差。这一发现归因于DNA光解酶关键位置的氨基酸残基偏差或光解酶基因的完全缺失。发现来自高太阳辐照度地表环境的几种菌株和物种对紫外线的耐受性最强，而来自湖泊沉积物的菌株具有中等耐受性。这些结果表明，高紫外线耐受性并非嗜盐古菌的统一特征，可能反映了它们在环境中所经历的紫外线照射情况。这是第一份将嗜盐古菌的天然紫外线耐受性与光解酶基因功能相关联的报告，并为它们在古代岩盐矿床以及可能在火星表面的生存提供了见解。
