Preston C M, Wu K Y, Molinski T F, DeLong E F
Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA.
Proc Natl Acad Sci U S A. 1996 Jun 25;93(13):6241-6. doi: 10.1073/pnas.93.13.6241.
Archaea, one of the three major domains of extant life, was thought to comprise predominantly microorganisms that inhabit extreme environments, inhospitable to most Eucarya and Bacteria. However, molecular phylogenetic surveys of native microbial assemblages are beginning to indicate that the evolutionary and physiological diversity of Archaea is far greater than previously supposed. We report here the discovery and preliminary characterization of a marine archaeon that inhabits the tissues of a temperate water sponge. The association was specific, with a single crenarchaeal phylotype inhabiting a single sponge host species. To our knowledge, this partnership represents the first described symbiosis involving Crenarchaeota. The symbiotic archaeon grows well at temperatures of 10 degrees C, over 60 degrees C below the growth temperature optimum of any cultivated species of Crenarchaeota. Archaea have been generally characterized as microorganisms that inhabit relatively circumscribed niches, largely high-temperature anaerobic environments. In contrast, data from molecular phylogenetic surveys, including this report, suggest that some crenarchaeotes have diversified considerably and are found in a wide variety of lifestyles and habitats. We present here the identification and initial description of Cenarchaeum symbiosum gen. nov., sp. nov., a symbiotic archaeon closely related to other nonthermophilic crenarchaeotes that inhabit diverse marine and terrestrial environments.
古菌是现存生命的三大主要域之一，曾被认为主要由栖息在极端环境中的微生物组成，这些环境不适宜大多数真核生物和细菌生存。然而，对天然微生物群落的分子系统发育调查开始表明，古菌的进化和生理多样性远比以前认为的要大得多。我们在此报告一种栖息于温带水海绵组织中的海洋古菌的发现及初步特征描述。这种关联是特异性的，单一的泉古菌谱系型栖息于单一的海绵宿主物种中。据我们所知，这种共生关系是首次描述的涉及泉古菌门的共生现象。这种共生古菌在10摄氏度的温度下生长良好，比任何已培养的泉古菌物种的最适生长温度低60多摄氏度。古菌通常被描述为栖息在相对有限生态位的微生物，主要是高温厌氧环境。相比之下，包括本报告在内的分子系统发育调查数据表明，一些泉古菌已经有了很大的分化，并且存在于各种各样的生活方式和栖息地中。我们在此展示对新属新种共生泉古菌（Cenarchaeum symbiosum）的鉴定及初步描述，这是一种与栖息于不同海洋和陆地环境的其他非嗜热泉古菌密切相关的共生古菌。
