First insight into IPL composition of a mesophilic ANME-1 enrichment.
Differential label uptake into archaeal di- and tetraether IPLs.
Label uptake into IPLs likely reflects tetraether biosynthetic pathway of ANME-1.
GDGTs likely represent end product in the lipid biosynthetic pathway of ANME-1.
Widespread presence of glycosidic GDGTs may indicate less active ANME-1 communities.