English: Ultrastructure of Bodo saltans virus (BsV, Theiavirus salishense) particles and replication. (A) Mature BsV virion: DNA containing core is surrounded by two putative membranous layers. The capsid consists of at least two proteinaceous layers. The bright halo hints to the presence of short (~40 nm) fibers as observed in Acantha polyphaga memivirus (ApMV). The top vertex of the virion contains a possible stargate structure. (Scale bar = 100 nm) (B) Healthy Bodo saltans cell: Nucleus with nucleolus and heterochromatin structures (Back arrow head) and kinetoplast genome (white arrow head) are clearly visible. (Scale bar = 500 nm) (C) Cell of B. saltans 24 hr post-BsV infection: Most subcellular compartments of healthy cells have been displaced by the virus factory now taking up a third of the cell. Virion production is directed toward the periphery of the cell (black arrow). Kinetoplast genome remains intact (white arrow head) while the nuclear genome is degraded (black arrow head; Scale bar = 500 nm) (D) BsV virion assembly and maturation: Lipid vesicles migrate through the virion factory where capsid proteins attach for the proteinaceous shell. Vesicles burst and accumulate at the virus factory periphery where the capsid assembly completes (black arrow). Once the capsid is assembled, the virion is filled with the genome and detaches from the virus factory. Internal structures develop inside the virion in the cell’s periphery where mature virions accumulate until the host cell bursts (Scale bar = 500 nm).