Studies on the Epidermis of Temnocephala Iv. Observations on the Ultrastructure of the Epidermis of Temnocephala Dendyi, With Notes on the Role of the Golgi Apparatus in Autolysis.

Abstract

The epidermis of Temnocephala dendyi is a patchwork of several syncytial epithelia with different structural and functional characteristics. Adjacent epithelia are limited by lateral plasma membranes and cohere by junctional structures. Cell processes which protrude into the epidermis appear to function in the transport of metabolites. Small vesicles fuse to form the double isolation membranes of autophagosomes: larger, Golgi-derived vesicles, interpreted as primary lysosomes, are enclosed with the sequestered cytoplasm. The formation of autolysosomes from autophagosomes is described. A possible mode of formation of myelin figures in autolysis is suggested. Autolysosomes form linear sequences and may occur in close association with Golgi cisternae. Advanced autolysosomes or residual bodies are transported elsewhere by phagocytic cells of the parenchyma. Starvation evidently induces a greatly enhanced autophagy, with presumed diminution in volume, in the temnocephalid epidermis. [For part III see Hm/A 48, 1332.] [AS]