FIG 7.

TEM images of thin sections of the methanogenic limonene enrichment culture showing the attack by OP3 LiM ultramicrobacteria of a large bacterial cell (A) and of a small archaeal cell (B). Ultramicrobial cells with a strongly stained part of the cytosol were assigned to OP3 LiM (triangles) based on the frequency of occurrence of this cell type in the thin-section TEM images. The small irregular cells with intense staining and a characteristic surface structure, likely S-layer protein, were assigned to archaeal cells, likely Methanoculleus-related species. Bars, 100 nm.