Journalartikel

Autorenliste: SEIFERT, G; ROSENBERG, J

Jahr der Veröffentlichung: 1976

Seiten: 23-37

Bandnummer: 85

Heftnummer: 1

Abstract: 
In O. gracilis nephrocytes are present in the pericardial and in the perivisceral sinus of the trunk from the collum in all except the last 2 metameres. They are attached individually or connected in groups by their continuous basement membrane to lobes of the fat body, muscles, connective tissue or tracheae. The greatest part of their surface is surrounded by hemolymph. The cell cortex has stalk-like processes between which an extracellular labyrinth extends. Near the cell surface the processes are linked together by diaphragms. These are composed of screenlike structures embedded in a less dense matrix. At the sites where the diaphragm is apposed, electron-dense material is attached to the cell membrane within the processes as in desmosomes. The nephrocyte is surrounded by its basement membrane. Along the labyrinth channels vesicular invaginations of the plasma membrane occur. They become coated vesicles within the cytoplasm. There are characteristic tubular structures bounded by a unit membrane with a specifically patterned inner lining. The tubules seem to transform into transparent vacuoles, situated generally close to the labyrinth. Between all structures free ribosomes are numerous. Occasionally a few microtubules and small mitochondria can be seen within the cortical region. Within the central area of the cell there is 1 nucleus, 1 or a few concrement -vacuoles, numerous Golgi dictyosomes, mitochondria and free ribosomes. The endoplasmic reticulum is only weakly developed; its membranes are predominantly smooth. It is more prominent if the central region is filled with vacuoles of variable contents. Then the Golgi apparatus is also more prominent, and mitochondria are increased in number. The vacuoles seem to be formations of the dictyosomes. They are interpreted as (secondary) lysosomes. Concrement -vacuoles may possibly represent autolysosomes. Terminological problems and the fine structure of the cell type described is discussed. Comparisons especially with pericardial cells of insects could be made. Nephrocytes are looked upon as organs analogous to the reticuloendothelial system of vertebrates. The ecdysial glands of centipedes and millipedes are considered specialized nephrocytes.

Harvard-Zitierstil: SEIFERT, G. and ROSENBERG, J. (1976) ULTRASTRUCTURE OF NEPHROCYTES OF ORTHOMORPHA-GRACILIS (KOCH,CL 1847) (DIPLOPODA, STRONGYLOSOMIDAE), 85(1), pp. 23-37

APA-Zitierstil: SEIFERT, G., & ROSENBERG, J. (1976). ULTRASTRUCTURE OF NEPHROCYTES OF ORTHOMORPHA-GRACILIS (KOCH,CL 1847) (DIPLOPODA, STRONGYLOSOMIDAE). 85(1), 23-37.