Chiu Beverly K, Waldbauer Jacob, Elling Felix J, Mete Öykü Z, Zhang Lichun, Pearson Ann, Eggleston Erin M, Leavitt William D
Department of Earth Sciences, Dartmouth College, Hanover, NH, United States.
Department of the Geophysical Sciences, The University of Chicago, Chicago, IL, United States.
Front Microbiol. 2023 Aug 15;14:1219779. doi: 10.3389/fmicb.2023.1219779. eCollection 2023.
Archaea adjust the number of cyclopentane rings in their glycerol dibiphytanyl glycerol tetraether (GDGT) membrane lipids as a homeostatic response to environmental stressors such as temperature, pH, and energy availability shifts. However, archaeal expression patterns that correspond with changes in GDGT composition are less understood. Here we characterize the acid and cold stress responses of the thermoacidophilic crenarchaeon REY15A using growth rates, core GDGT lipid profiles, transcriptomics and proteomics. We show that both stressors result in impaired growth, lower average GDGT cyclization, and differences in gene and protein expression. Transcription data revealed differential expression of the GDGT ring synthase in response to both acid stress and cold stress. Although the GDGT ring synthase encoded by forms highly cyclized GDGTs with ≥5 ring moieties, upregulation under acidic pH conditions did not correspond with increased abundances of highly cyclized GDGTs. Our observations highlight the inability to predict GDGT changes from transcription data alone. Broader analysis of transcriptomic data revealed that differentially expresses many of the same transcripts in response to both acid and cold stress. These included upregulation of several biosynthetic pathways and downregulation of oxidative phosphorylation and motility. Transcript responses specific to either of the two stressors tested here included upregulation of genes related to proton pumping and molecular turnover in acid stress conditions and upregulation of transposases in cold stress conditions. Overall, our study provides a comprehensive understanding of the GDGT modifications and differential expression characteristic of the acid stress and cold stress responses in .
古菌会调整其二植烷甘油四醚（GDGT）膜脂中环戊烷环的数量，作为对温度、pH值和能量可用性变化等环境应激源的稳态反应。然而，与GDGT组成变化相对应的古菌表达模式却鲜为人知。在此，我们利用生长速率、核心GDGT脂质谱、转录组学和蛋白质组学来表征嗜热嗜酸泉古菌REY15A的酸应激和冷应激反应。我们发现这两种应激源都会导致生长受损、平均GDGT环化程度降低以及基因和蛋白质表达的差异。转录数据显示，GDGT环合酶在酸应激和冷应激反应中均有差异表达。尽管由其编码的GDGT环合酶会形成具有≥5个环部分的高度环化的GDGT，但在酸性pH条件下的上调与高度环化的GDGT丰度增加并不对应。我们的观察结果突出表明，仅从转录数据无法预测GDGT的变化。对转录组数据的更广泛分析表明，REY15A在酸应激和冷应激反应中差异表达许多相同的转录本。这些包括几种生物合成途径的上调以及氧化磷酸化和运动性的下调。此处测试的两种应激源中任何一种特有的转录反应包括酸应激条件下与质子泵浦和分子周转相关基因的上调以及冷应激条件下转座酶的上调。总体而言，我们的研究全面了解了REY15A中酸应激和冷应激反应的GDGT修饰和差异表达特征。
