The fine structure and histochemistry of bleb-like extrusions in the microthrix border of the larval Multiceps endothoracicus.

The study on the fine structure and the histochemistry of microtriches in the spiral canal and the scolex of a larva of the polycephalic cestode Multiceps endothoracicus suggested a defensive mechanism of a part of the parasite against invading cells of the parasite against invading cells of the tissue reaction of the host. Numerous vesicles and bleb-like extrusions were present in the transitory zone of the opening of the spiral canal and in the rostellar region of the scolex in close contact with deteriorating host cells. Both, the vesicles and bleb-like extrusions gave a positive reaction for SS and SH groups and displayed an enzymatic activity of acid phosphatase (AP) and nonspecific esterase (NE). Scanning and transmissive electron microscopy revealed the process of formation of bleb-like extrusions from the distal cytoplasm and showed that the appearance of the microtriches was being changed by an accumulation of products of secernation and secretion responsible for a lysis of the host cells.