Adaptation of lipid membrane composition is an important component of archaeal homeostatic response. Historically, the number of cyclopentyl and cyclohexyl rings in the glycerol dibiphytanyl glycerol tetraether (GDGT) Archaeal lipids has been linked to variation in environmental temperature. However, recent work with GDGT‐making archaea highlight the roles of other factors, such as pH or energy availability, in influencing the degree of GDGT cyclization. To better understand the role of multiple variables in a consistent experimental framework and organism, we cultivated the model Crenarchaeon Sulfolobus acidocaldarius DSM639 at different combinations of temperature, pH, oxygen flux, or agitation speed. We quantified responses in growth rate, biomass yield, and core lipid compositions, specifically the degree of core GDGT cyclization. The degree of GDGT cyclization correlated with growth rate under most conditions. The results suggest the degree of cyclization in archaeal lipids records a universal response to energy availability at the cellular level, both in thermoacidophiles, and in other recent findings in the mesoneutrophilic Thaumarchaea. Although we isolated the effects of key individual parameters, there remains a need for multi‐factor experiments (e.g., pH + temperature + redox) in order to more robustly establish a framework to better understand homeostatic membrane responses.

中文翻译：

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多个环境参数影响在嗜盐球菌中的脂质环化。

脂质膜组成的适应是古细菌稳态反应的重要组成部分。从历史上看，甘油二双二十烷基甘油四醚（GDGT）古生脂质中环戊基和环己基环的数量与环境温度的变化有关。但是，最近与制造GDGT的古细菌有关的工作强调了其他因素（例如pH或能量可用性）在影响GDGT环化程度方面的作用。为了更好地理解多个变量在一致的实验框架和生物中的作用，我们培养了Crenarchaeon Sulfolobus acidocaldarius模型DSM639在温度，pH，氧气流量或搅拌速度的不同组合下使用。我们量化了增长率，生物量产量和核心脂质组成，特别是核心GDGT环化程度的响应。在大多数条件下，GDGT环化程度与生长速率相关。结果表明，古菌脂质中的环化程度在嗜热嗜酸菌中和中性嗜中性Thaumarchaea的其他近期发现中都记录了对细胞水平能量利用的普遍反应。尽管我们隔离了关键参数的影响，但仍需要进行多因素实验（例如pH +温度+氧化还原），以便更稳健地建立一个框架，以更好地了解稳态膜反应。