A granular sporoplasm
is located between polar capsules.
was observed in the final portion of the spore body (Figure 1D).
cells of 9-12 [micro]m in diameter showed a central basophilic nucleus surrounded by nonvacuolated, acidophilic cytoplasm (Fig.
Infection occurs when the polar tubule is extruded from the spore and sporoplasm
is introduced into the host cell through the tubule (7).
If the Lom and Vavra model is correct, the membrane of the extruded sporoplasm
may be derived from the extrusion apparatus and may therefore be reversed.
A remarkable survival adaptation of microsporidians is the spore extrusion apparatus (EXA), which is equipped to explosively discharge a tube through which the infective sporoplasm
is sent into a host cell.
The spore contents (sporoplasm
) pass through the invasion tube and are introduced into a target cell.
Microsporeans have an infective spore stage that discharges the sporoplasm
from a long, fine tube.
The infective spore stages of Spraguea are activated to discharge in Lophius surface mucus, and it is therefore believed that peripheral fibers of the fish may be parasitized directly upon the injection of sporoplasm
from the activated spore into the nerve fiber.
The failure rate of sporoplasmic sac emergence or of sporoplasm
extrusion was increased with extended spore incubations (6-12 h) in higher concentrations of DAPI (50 [[micro]molar]).
Using DIC imaging with DAPI fluorescence, we observed nuclear movement in association with the reformation of the invasion tube and the emergence of the sporoplasm
of Spraguea lophii (Microsporidia)