Paerl H W, Pinckney J L, Steppe T F
Institute of Marine Sciences, University of North Carolina at Chapel Hill, 28557, USA.
Environ Microbiol. 2000 Feb;2(1):11-26. doi: 10.1046/j.1462-2920.2000.00071.x.
Cyanobacterial-bacterial consortial associations are taxonomically complex, metabolically interactive, self-sustaining prokaryotic communities representing pioneer and often the only biota inhabiting extreme aquatic and terrestrial environments. Laminated mats and aggregates exemplify such communities. The fossil record indicates that these associations represent the earliest extant inhabitants and modifiers (i.e. anoxic to oxic conditions) of the Earth's biosphere. Present-day consortia flourish in physically and chemically stressed environments, including nutrient-deplete, hypersaline, calcified, desiccated and high-irradiance ecosystems ranging from the tropics to polar regions. Consortial members exhibit extensive metabolic diversification, but have remained structurally simple. Structural simplicity, while advantageous in countering environmental extremes, presents a 'packaging problem' with regard to compartmentalizing potentially cross-inhibitory aerobic versus anaerobic growth processes. To circumvent these metabolic constraints, phototrophic cyanobacteria and microheterotrophs orient along microscale chemical (i.e. O2, pH, Eh) gradients to meet and optimize the biogeochemical processes (C, N, S cycling) essential for survival, growth and the maintenance of genetic diversity, needed to sustain life. Microscale ecophysiological, analytical, molecular (immunological and nucleic acid) techniques have helped to develop a mechanistic basis for understanding consortial growth and survival under extreme environmental conditions on Earth. Consortia are ideal model systems for developing a process-based understanding of the structural and functional requirements for life in extreme environments representative of the Earth's earliest biosphere and possibly other planets.
蓝细菌 - 细菌共生联合体是分类学上复杂、代谢相互作用、自我维持的原核生物群落，代表了居住在极端水生和陆地环境中的先驱生物群，且往往是唯一的生物群。层状垫和聚集体就是这类群落的例证。化石记录表明，这些联合体代表了地球生物圈最早现存的居民和环境修饰者（即从缺氧到有氧条件）。当今的共生联合体在物理和化学压力环境中蓬勃发展，包括从热带到极地地区的营养贫乏、高盐、钙化、干燥和高辐照生态系统。共生联合体成员表现出广泛的代谢多样性，但结构上仍很简单。结构简单虽然有利于应对极端环境，但在区分潜在相互抑制的需氧与厌氧生长过程方面存在“包装问题”。为了规避这些代谢限制，光合蓝细菌和微异养生物沿着微观化学（即氧气、pH值、氧化还原电位）梯度定向，以满足并优化生存、生长和维持遗传多样性所必需的生物地球化学过程（碳、氮、硫循环），而这些过程是维持生命所需的。微观生态生理学、分析、分子（免疫和核酸）技术有助于建立一个机制基础，以理解共生联合体在地球极端环境条件下的生长和生存情况。共生联合体是理想的模型系统，有助于基于过程理解代表地球最早生物圈以及可能其他行星的极端环境中生命的结构和功能要求。
