Research domain


Taxonomic markers



A predatory mode whereby a cell can penetrate the cortex and draw in the cytoplasmic contents of a prey or host cell. The prey is suctioned into a food vacuole via a feeding tube or peduncle, and then digested.
In paulsenella feeding on Streptotheca, feeding tube pierces the host plasmalemma and forms a channel of variable diameter which enlarges proximally to form the food vacuole. The tube consists of a thin cytoplasmic mantle with rows of microtubules as cytoskeletal elements. The host plasmalemma closely attaches to the outer membrane of the tube sealing the host protoplast here. The host cytoplasm is sucked up gradually through the tube, not being delimited against the inner tube membrane and the membrane of the food vacuole by an own membrane. This kind of endocytosis differs from phagocytosis in that it is a rather long-lasting process during which the plasmalemma of the engulfed cell is not taken up and in that parts of the host cytoplasm may be left.
Endosymbionts taken up by phagocytosis are, in general, delimited by two membranes. The outer one is the membrane of the former "food vacuole", the inner one the plasmalemma of the symbiont. Secondary endosymbioses occurred by myzocytosis in dinoflagellates, leading to a system of three membranes around plastids, with the total lost of the external membrane of the primary algae. In tertiary endosymbioses, myzocytosis could provided a system with 5 membranes around plastids/symbionts.

Related glossary terms