English: Transmission electron microscopy (TEM) images of Novymonas esmeraldas and “Ca. Pandoraea novymonadis”

(A) General view of Novymonas cell showing typical features of trypanosomatids such as the nucleus (n), kinetoplast (k), mitochondrion (m), and flagellar pocket (fp), as well as the bacterial symbionts (b).

(B) Interaction between the bacteria and the trypanosomatid cell demonstrating fusion of lysosomes (ly) with bacterium-containing vacuoles in the cytoplasm of the host (ch). Intact and degrading bacteria are labeled ib and db, respectively.

(C) Magnification of boxed part of panel B showing the membrane (arrowhead) of the symbiontophorous vacuole (sv), bacterial cell wall (white asterisk), periplasmic space (black asterisk), and internal membrane (arrow).

(D) Cross section of Novymonas cell showing mitochondrial hypertrophy.

(E) The early stage of the fusion between a bacterium and a lysosome.

(F) Endosymbiotic bacillus in the axenic culture of “Ca. P. novymonadis” with the same structure of cell covering as is seen in panel C.

Scale bars are 1 µm (A, D), 500 nm (B), 100 nm (C), and 200 nm (E, F).