Feyhl-Buska Jayme, Chen Yufei, Jia Chengling, Wang Jin-Xiang, Zhang Chuanlun L, Boyd Eric S
Department of Microbiology and Immunology, Montana State University Bozeman, MT, USA.
State Key Laboratory of Marine Geology, Tongji University Shanghai, China.
Front Microbiol. 2016 Aug 30;7:1323. doi: 10.3389/fmicb.2016.01323. eCollection 2016.
The abundance and composition of glycerol dibiphytanyl glycerol tetraether (GDGT) and glycerol tribiphytanyl glycerol tetraether (GTGT) lipids were determined as a function of growth phase as a proxy for nutrient availability, the pH of growth medium, and incubation temperature in cultures of the thermoacidophile Picrophilus torridus. Regardless of the cultivation condition, the abundance of GDGTs and GTGTs was greater in the polar than core fraction, with a marked decrease in core GDGTs in cultures harvested during log phase growth. These data are consistent with previous suggestions indicating that core GDGTs are re-functionalized during polar lipid synthesis. Under all conditions examined, polar lipids were enriched in a GDGT with 2 cyclopentyl rings (GDGT-2), indicating GDGT-2 is the preferred lipid in this taxon. However, lag or stationary phase grown cells or cells subjected to pH or thermal stress were enriched in GDGTs with 4, 5, or 6 rings and depleted in GDGTs with 1, 2, 3, rings relative to log phase cells grown under optimal conditions. Variation in the composition of polar GDGT lipids in cells harvested during various growth phases tended to be greater than in cells cultivated over a pH range of 0.3-1.1 and a temperature range of 53-63°C. These results suggest that the growth phase, the pH of growth medium, and incubation temperature are all important factors that shape the composition of tetraether lipids in Picrophilus. The similarity in enrichment of GDGTs with more rings in cultures undergoing nutrient, pH, and thermal stress points to GDGT cyclization as a generalized physiological response to stress in this taxon.
测定嗜热嗜酸菌嗜热栖热袍菌培养物中甘油二植烷甘油四醚（GDGT）和甘油三植烷甘油四醚（GTGT）脂质的丰度和组成，将其作为生长阶段的函数，以代表营养物质可用性、生长培养基的pH值和培养温度。无论培养条件如何，GDGTs和GTGTs在极性部分的丰度都高于核心部分，在对数期生长收获的培养物中，核心GDGTs显著减少。这些数据与之前的推测一致，即核心GDGTs在极性脂质合成过程中被重新功能化。在所有检测条件下，极性脂质中富含具有2个环戊基环的GDGT（GDGT-2），表明GDGT-2是该分类群中的首选脂质。然而，与在最佳条件下生长的对数期细胞相比，处于延迟期或稳定期的生长细胞或受到pH或热应激的细胞富含具有4、5或6个环的GDGTs，而具有1、2、3个环的GDGTs则减少。在不同生长阶段收获的细胞中，极性GDGT脂质组成的变化往往大于在pH范围为0.3-1.1和温度范围为53-63°C下培养的细胞。这些结果表明，生长阶段、生长培养基的pH值和培养温度都是影响嗜热栖热袍菌四醚脂质组成的重要因素。在经历营养、pH和热应激的培养物中，富含更多环的GDGTs的富集相似性表明，GDGT环化是该分类群对压力的一种普遍生理反应。
