Ref ID : 7696
Susanne Kuhlmann and Klaus Hausmann; [Ultrastrukturelle Untersuchungen zur Nahrungsaufnahme bei Homalozoon vermiculare Stokes, 1887]. Protistologica XIX(1):111-122, 1983
Reprint
In File
Notes
Homalozoon vermiculare Stokes, 1887, is a gymnostome, predatory ciliate which ingests its prey within 60-80 seconds. The process of food uptake is documented by scanning and transmisson electron microscopical studies. The beginning of phagocytosis - after the discharge of toxicysts - is characterized by the fusion of numerous small vesicles in the oral region. In consequence, a longish, slender vacuole is formed. This vacuole fuses with the plasmamembrane. Then the oral region widens and the organelles which occupy the oral region in a regular, spatial distribution, are moved toward its edge. Small vesicles fuse permanently with the food vacuole, which thereby grows continuously. Frequently an everted bulge is produced, which encircles the oral region. The nemadesmata of the oral apparatus follow the contour of this bulge, actively or passively. After complete enclosure of the prey, the food vacuole is pinched off from the plasmamembrane. Finally, the reorganization of the oral region to its inactive state takes place. Seemingly, the parapharyngeal mass is not directly involved in the process of food uptake.