Intact polar membrane lipids (IPLs) are the building blocks of all cell membranes. There is a wide range of phosphorus-free IPL structures, including amino acid containing IPLs, that can be taxonomically specific. Trimethylornithine membrane lipids (TMOs) were discovered in northern wetland Planctomycete species that were isolated and described in the last decade. The trimethylated terminal nitrogen moiety of the ornithine amino acid in the TMO structure gives the lipid a charged polar head group, similar to certain phospholipids. Since their discovery, TMOs have been identified in various other recently described northern latitude Planctomycete species, and in diverse environments including tundra soil, a boreal eutrophic lake, meso-oligotrophic lakes, and hot springs. The majority of environments or enrichment cultures in which TMOs have been observed include predominately heterotrophic microbial communities involved in the degradation of recalcitrant material and/or low oxygen methanogenic conditions at primarily northern latitudes. Other ecosystems occupied with microbial communities that possess similar metabolic pathways, such as tropical peatlands or coastal salt marshes, may include TMO producing Planctomycetes as well, further allowing these lipids to potentially be used to understand microbial community responses to environmental change in a wide range of systems. The occurrence of TMOs in hot springs indicates that these unique lipids could have broad environmental distribution with different specialized functions. Opportunities also exist to investigate the application of TMOs in microbiome studies, including forensic necrobiomes. Further environmental and microbiome lipidomics research involving TMOs will help reveal the evolution, functions, and applications of these unique membrane lipids.

中文翻译：

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三甲基鸟氨酸膜脂质：在轮菌中发现并在多种环境中鉴定

完整的极性膜脂质（IPL）是所有细胞膜的组成部分。有各种各样的无磷IPL结构，包括含氨基酸的IPL，它们在分类上是特定的。Trimethylornithine膜脂（TMOS）在北部湿地被发现浮霉菌门进行分离，在过去十年中描述的物种。TMO结构中鸟氨酸氨基酸的三甲基化末端氮部分使脂质具有带电荷的极性头基，类似于某些磷脂。自发现以来，TMOs已在其他最近描述的北纬Planctomycete中被发现。物种，并在不同的环境中生存，包括苔原土壤，北方富营养化湖泊，中营养贫化湖泊和温泉。已观察到TMO的大多数环境或富集培养物主要包括异养微生物群落，这些微生物群主要在北纬地区参与了难降解物质的降解和/或低氧产甲烷条件。其他具有类似代谢途径的微生物群落所占据的其他生态系统，例如热带泥炭地或沿海盐沼，可能包括产生TMO的Planctomycetes同样，进一步允许这些脂质潜在地用于理解微生物群落对多种系统中环境变化的反应。温泉中TMO的出现表明这些独特的脂质可能具有广泛的环境分布，具有不同的特殊功能。还存在机会研究TMO在微生物组研究（包括法医坏死生物群落）中的应用。涉及TMO的进一步环境和微生物组脂质组学研究将有助于揭示这些独特的膜脂质的进化，功能和应用。