Figure 4
Morphology of Entomospira gen. nov. isolate BR151. (A) Negatively stained intact bacteria. (B) The periplasmic flagella are enclosed in the periplasmic space located between an outer (black arrowheads) and an inner membrane (white arrowhead). Flagellar motors are present near the end of the protoplasmic cylinder and close to approximately 30 nm thick multilayered structure/array (clip). A cap-like structure (white arrow) merges with the inner peptidoglycan layer/cytoplasmic membrane (white arrows) in the cell tip. The terminal part of cells contains fine fibers (grey arrow). (C) Quantification of size and morphology of bacteria based on measurements of negatively stained bacteria (light grey box) and cross-sections (yellow box). (D) Within the inner membrane, the tomographic slice of the end part reveals the presence of two multilayered arrays located sub-terminally and “cap”-like structure in the tip. Above the cap structure, tiny fibrils (white arrow) filled the cell tip. (E) Enlarged area from (D). (F) 3D reconstruction of the spirochete from (D) using the software SerialEM v. 3.7.616 and IMOD v. 4. 10.3017 both downloaded from https://bio3d.colorado.edu. (G,H) Two tomographic slices from different depths of the same spirochete. At the end part of the spirochete numerous flagellar motors (black arrows) are present with arising flagella (white arrows), tiny filaments (asterisk) and the multilayered array (clip). White arrows show the cap-like structure, grey arrows fibrils at the tip of the spirochete. Bars: 5 µm (A), 200 nm (B), 100 nm (D,F–H), 50 nm (E).
