Hellequin Eve, Collin Sylvie, Seder-Colomina Marina, Véquaud Pierre, Anquetil Christelle, Kish Adrienne, Huguet Arnaud
Sorbonne Université, CNRS, EPHE, PSL, UMR METIS, Paris, France.
Muséum National d'Histoire naturelle, CNRS, Unité Molécules de Communication et Adaptation des Microorganismes UMR7245 MCAM, Paris, France.
Front Microbiol. 2023 Mar 6;14:1032032. doi: 10.3389/fmicb.2023.1032032. eCollection 2023.
3-hydroxy fatty acids (3-OH FAs) are characteristic components of the Gram-negative bacterial membrane, recently proposed as promising temperature and pH (paleo) proxies in soil. Nevertheless, to date, the relationships between the 3-OH FA distribution and temperature/pH are only based on empirical studies, with no ground truthing work at the microbial level. This work investigated the influence of growth temperature and pH on the lipid composition of three strains of soil Gram-negative bacteria belonging to the phylum. Even though non-hydroxy FAs were more abundant than 3-OH FAs in the investigated strains, our results suggest that 3-OH FAs are involved in the membrane adaptation of these bacteria to temperature. The strains shared a common adaptation mechanism to temperature, with a significant increase in the ratio of vs. or 3-OH FAs at lower temperature. In contrast with temperature, no common adaptation mechanism to pH was observed, as the variations in the FA lipid profiles differed from one strain to another. We suggest that models reconstructing environmental changes in soils should include the whole suite of 3-OH FAs present in the membrane of Gram-negative bacteria, as all of them could be influenced by temperature or pH at the microbial level.
3-羟基脂肪酸（3-OH FAs）是革兰氏阴性细菌细胞膜的特征性成分，最近被认为是土壤中有前景的温度和pH（古环境）替代指标。然而，迄今为止，3-OH FA分布与温度/pH之间的关系仅基于实证研究，在微生物层面上尚无实地验证工作。本研究调查了生长温度和pH对属于该门的三株土壤革兰氏阴性细菌脂质组成的影响。尽管在所研究的菌株中非羟基脂肪酸比3-OH FAs更丰富，但我们的结果表明3-OH FAs参与了这些细菌对温度的膜适应性调节。这些菌株对温度具有共同的适应机制，在较低温度下，与 或3-OH FAs的比例显著增加。与温度不同，未观察到对pH的共同适应机制，因为脂肪酸脂质谱的变化因菌株而异。我们建议，重建土壤环境变化的模型应包括革兰氏阴性细菌膜中存在的全套3-OH FAs，因为所有这些都可能在微生物层面受到温度或pH的影响。
