Oren Aharon
Department of Plant and Environmental Sciences, The Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, 91904, Jerusalem, Israel,
Extremophiles. 2014 Sep;18(5):825-34. doi: 10.1007/s00792-014-0654-9. Epub 2014 Aug 8.
Several groups of Archaea, all Euryarchaeota, develop in hypersaline environments (from >10% salt up to saturation). The cultured diversity of halophilic Archaea includes the family Halobacteriaceae of aerobic or facultative anaerobic, generally red-pigmented species (47 genera and 165 species as of February 2014) and seven representatives of four genera of methanogens, most of which obtain energy from methylated amines under anaerobic conditions. Metagenomic studies have identified an additional deep lineage of Archaea in salt lakes and ponds with brines approaching NaCl saturation. Genomic information is now available for representatives of these 'Nanohaloarchaea', but no members of this lineage have yet been cultured. Multilocus sequence analysis is becoming increasingly popular in taxonomic studies of the Halobacteriaceae, and such studies have demonstrated that recombination of genetic traits occurs at an extremely high frequency at least in some genera. Metagenomic studies in an Antarctic lake showed that large identical regions of up to 35 kb in length can be shared by members of different genera living together in the same environment. Such observations have important implications not only for the taxonomy of the Halobacteriaceae, but also for species concepts and questions on taxonomy and classification for prokaryotic microorganisms in general.
几组古菌，均属于广古菌门，在高盐环境（盐含量大于10%直至饱和）中生长。嗜盐古菌的培养多样性包括需氧或兼性厌氧、通常呈红色的嗜盐杆菌科（截至2014年2月有47个属和165个种）以及四个属的七株产甲烷菌代表，其中大多数在厌氧条件下从甲基化胺获取能量。宏基因组学研究在盐湖和盐度接近氯化钠饱和的池塘中鉴定出了古菌的另一个深层谱系。现在已有这些“纳米嗜盐古菌”代表的基因组信息，但该谱系尚无成员被培养出来。多位点序列分析在嗜盐杆菌科的分类学研究中越来越受欢迎，此类研究表明至少在某些属中遗传性状的重组以极高频率发生。在一个南极湖泊中的宏基因组学研究表明，共同生活在同一环境中的不同属成员可共享长达35 kb的大片相同区域。这些观察结果不仅对嗜盐杆菌科的分类学有重要意义，对一般原核微生物的物种概念以及分类学和分类问题也有重要意义。
