Dr. rer. nat. K. Zanger :
[ 90 kB, GIF ]
ABSTRACTS :
Immunocytochemical localization of lysozyme in the nephrocytes
of the harvestman, Leiobunum rotundum
Tissue & Cell, 27 (3) 299-308, 1995
Dr. rer. nat. K. Zanger :
[ 90 kB, GIF ]
Immunocytochemical localization of lysozyme in the nephrocytes
of the harvestman, Leiobunum rotundum
Tissue & Cell, 27 (3) 299-308, 1995
Nephrocytes are cells involved in the metabolism of hemolymph components and are characterized by peripheral finger-like projections bordering a labyrinthine channel system. The antibacterial protein lysozyme was localized in anterior and pericardial nephrocytes of the harvestman, Leiobunum rotundum, by biochemical and immuno-gold postembedding-labelling techniques. Lysozyme-activity was demonstrated in experimental animals, challenged by Micrococcus luteus Gram-positive bacteria. With SDS-electrophoresis, lysozyme was proved to be present in nephrocytes adjoining the heart, before studies at the electron microscopical level were carried out. The opilionid lysozyme was found to have a molecular weight of 14,500 Da, thus belonging to the c-type lysozyme which is represented by hen egg white lysozyme. In untreated animals the presence of lysozyme could not be proved by electrophoresis. With immunogold labelling, however, lysozyme could be clearly localized in the vesicles of nephrocytes of untreated animals. Additional control experiments were carried out which revealed that the nephrocytes of L. rotundum in-vivo are able to take up native lysozyme from an exterior medium. Therefore, the problem needs to be solved if nephrocyte-vesicles transport lysozyme into or out of the cell.
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Zanger K, Dannhorn DR, Seitz KA, Peters W (1991) Nephrocytes of
harvestmen, Leiobunum limbatum and L. rotundum.
Tissue & Cell 23 (1): 7-15
Specific labeling of a nephrocyte vesicle by the immuno-gold complex
Abstract 2:
Tissue & Cell, 1991, 23 (1) pp. 7-15
Nephrocytes are said to be able to take up substances from the hemolymph. In Opiliones, which are examined electron microscopically, three different types of nephrocytes were found. Numerous large nephrocytes lie clustered between the muscles in the anterior region of the body. Smaller nephrocytes occur scattered throughout the opilionid body, often affixed to tracheoles. The third group, pericardial cells, are always attached to the heart by connective ligaments. All nephrocytes are surrounded by a thick basement membrane and their plasma membrane forms pedicels. Junctional complexes link the adjacent pedicels to form diaphragm-like slit-membranes, which form the entrance to an extracellular compartment. The cytoplasm of the nephrocytes contains many pinocytotic vesicles and tubular elements. Different types of large electron-dense and electron-lucent vesicles can be distinguished. Occasionally a large bundle of unmyelinated nerve fibers is enclosed by a pericardial cell. Morphological differences between the types of nephrocytes are described and the ultrastructural characteristics of the nephrocytes of harvestmen are compared with those of other arthropods. Functional aspects are discussed with respect to their ultrafiltration structures.
Harvestman Leiobunum rotundum
an mich.