Taenia crassiceps: basic mechanisms of endocytosis in the cysticercus.

The effects of glucose, yeast extract, fetal bovine serum albumin, and ruthenium red on endocytosis of smooth micropinocytotic vesicles (pinosomes) in the tegument of the cysticercus of Taenia crassiceps have been investigated stereologically. Glucose has been shown to stimulate pinocytosis, whether it was used alone or in combination with yeast extract or bovine serum albumin. Yeast extract was a stimulant of endocytosis. Bovine serum albumin was the most potent stimulant of all the substances investigated in this study. Although the time of incubation in ruthenium red was the same for all incubation experiments, varied numbers of ruthenium red-containing pinosomes were observed in different experiments. The role of ruthenium red as a stimulant and/or initiator of endocytosis and the possible explanations for differences in ruthenium red uptake are discussed.