English: Candidatus Prometheoarchaeum syntrophicum aka Lokiarchaeota sp. MK-D1.
"a–c, SEM images of MK-D1. Single cell (a), aggregated cells covered with EPS-like materials (b) and a dividing cell with polar chains of blebs (c). d, Cryo-electron tomography image of MK-D1. The top-right inset image shows a magnification of the boxed area to show the cell envelope structure. e, Cryo-EM image of large membrane vesicles attached to and surrounding MK-D1 cells. f, Ultrathin section of an MK-D1 cell and a membrane vesicle. The bottom-right inset image shows a magnified view of the membrane vesicle. g, h, SEM images of MK-D1 cells producing long branching (g) and straight (h) membrane protrusions. i, Ultrathin section of a MK-D1 cell with protrusions. j, A total ion chromatogram of gas chromatography–mass spectrometry (GC–MS) for lipids extracted from a highly purified MK-D1 culture. The chemical structures of isoprenoids and their relative compositions are also shown (Supplementary Fig. 2). Scale bars, 1 μm (b, c, g, h), 500 nm (a, d, e, i) and 200 nm (f). a–c, g, h, SEM images are representative of n = 122 recorded images that were obtained from four independent observations from four culture samples. d, e, Cryo-EM images are representative of n = 14 recorded images that were taken from two independent observations from two culture samples. f, i, The ultrathin section images are representative of n = 131 recorded images that were obtained from six independent observations from six culture samples. White arrows in the images indicate large membrane vesicles. The lipid composition experiments were repeated twice and gave similar results. Detailed iTAG-based community compositions of the cultures are shown in Supplementary Table 1."