Microbial lipids, used as taxonomic markers and physiological indicators, have mainly been studied through cultivation. However, this approach is limited due to the scarcity of cultures of environmental microbes, thereby restricting insights into the diversity of lipids and their ecological roles. Addressing this limitation, here we apply metalipidomics combined with metagenomics in the Black Sea, classifying and tentatively identifying 1623 lipid-like species across 18 lipid classes. We discovered over 200 novel, abundant, and structurally diverse sphingolipids in euxinic waters, including unique 1-deoxysphingolipids with long-chain fatty acids and sulfur-containing groups. Sphingolipids were thought to be rare in bacteria and their molecular and ecological functions in bacterial membranes remain elusive. However, genomic analysis focused on sphingolipid biosynthesis genes revealed that members of 38 bacterial phyla in the Black Sea can synthesize sphingolipids, representing a fourfold increase from previously known capabilities and accounting for up to 25% of the microbial community. These sphingolipids appear to be involved in oxidative stress response, cell wall remodeling and are associated with the metabolism of nitrogen-containing molecules. Our findings underscore the effectiveness of multi-omics approaches in exploring microbial chemical ecology.

中文翻译：

---

黑海水体中的厌氧海洋细菌生产结构多样的鞘脂


微生物脂质作为分类标记和生理指标，主要通过培养进行研究。然而，由于环境微生物培养物的缺乏，这种方法受到限制，从而限制了对脂质多样性及其生态作用的了解。为了解决这一限制，我们在黑海应用金属脂质组学与宏基因组学相结合，对 18 个脂质类别的 1623 个脂质样物种进行了分类和初步鉴定。我们在含氧水中发现了 200 多种新颖、丰富且结构多样的鞘脂，包括具有长链脂肪酸和含硫基团的独特 1-脱氧鞘脂。鞘脂被认为在细菌中很少见，并且它们在细菌膜中的分子和生态功能仍然难以捉摸。然而，针对鞘脂生物合成基因的基因组分析显示，黑海 38 个细菌门的成员可以合成鞘脂，比之前已知的能力增加了四倍，占微生物群落的 25%。这些鞘脂似乎参与氧化应激反应、细胞壁重塑，并与含氮分子的代谢相关。我们的研究结果强调了多组学方法在探索微生物化学生态学方面的有效性。