Some aspects of the infrastructure of the ‘Stäbchendrüscnzellen’, a peculiar cell associated with the endothelium of the bulbus arteriosus and with other fish tissues*

Abstract

The fine structure of an unusual cell, the ‘Stäbchendriisenzellen’ (the so‐called foliaceous or rodlet cells of several authors), associated with the endothelium of the vascular system of marine and freshwater fishes was studied in the goldfish Carassius auratus (L.). The bulbus arteriosus was fixed with either a 6 % solution of buffered glutaraldehyde or with one part of a 3 % solution of lanthanum nitrate plus two parts of a 3 % solution of buffered glutaraldehyde and then post‐fixed in a 1.2% solution of osmium tetroxide. Electron micrographs of the vascular tissue show four cell forms which appear to be phases in the life cycle of the endothelium‐associated cell. Two of the phases are not encased and are characterized by their inclusions: in one cell these are crystalline, while in the second, they are amorphous and granular. In the other phases the cell is encased partially or completely within an apparently contractile fibrous wall surrounded by the plasmalemma. In the encased phases, the arrangement and condition of the cell organelles appears to have been changed, and in the fully‐encased phase mitochondrial activity seems to have decreased. This apparent change in the mitochondrial activity is accompanied by a thickening of the mitochondrial membrane from 48 to 109 Å. The micrographs seem to indicate that this cell in question behaves as a foreign body and, in some way, may be interacting with the epithelial tissue of the bulbus arteriosus.

The rodlet cells of teleostean fish: their potential role in host defence in relation to the role of mast cells/eosinophilic granule cells

“…Among the earlier studies on rodlet cell distribution in individual species of the cyprinid family there are some that also include observations on the bulbus arteriosus, showing the presence of rodlet cells in this location in the tench and carp [3,45], and the goldfish [14,41,46], in agreement with results of the present study. In the carp, rodlet cells were found even in the bulbus arteriosus of very young specimens [45].…”

Rhabdospora thelohani: Epidemiology of and migration into Cyprinus carpio bulbus arteriosus.

“…PLEHN (1906) hypothesized a glandular function for the organisms she observed in carp and trout bulbi. LEINO (1974) supported this hypothesis with observations of partially disen tigrating rhabdosporans associated with shiner ventral aortic endothelium. No rhabdosporans, however, were observed discharging their con tents or disentigrating in the present study.…”

“…Statements such as the following, "The micrographs seem to indicate that this cell in question behaves as a foreign body and, in some way, may be interacting with the epithelial cell of the bulbus arteriosus. ", by FLOOD et al (1975) lead to an interesting speculation. Could it be that the organisms were once fish parasites, but are now evolving into fish cells in a similar manner to that postulated for the evolution of mitochondria from prokaryotes?…”

“…Several researchers have described the ultrastructure of less differentiated or immature rodlet cell stages (LEINO 1974;DESSER and LESTER 1975;FLOOD et al, 1975;BARBER et al., 1979). LEINO (1974) indicated that early rodlet cells are not easily distinguishable from other undifferen tiated cells near the basement membrane, suggest ing that pre-rodlet cell stages can be traced by their characteristic organelles to a point in de velopment but not back to the mitotic stem cell stage.…”

Inflammatory cells of teleostean fish: A review focusing on mast cells/eosinophilic granule cells and rodlet cells

“…As to the nature of the rodlet cell, whether it is a type of granular leucocyte [46,57,82] or has a glandular nature [83,94,95,98], a uniting view, that the rodlet cell is a cell type resembling eosinophilic granulocytes that invade the tissues at its immature stage, as a rodlet cell precursor, in a way similar to that of mast cell precursors, and mature into a secretory cell in response to the appropriate stimuli [55], should be considered. The crystalline structure of the central core of the inclusions of the rodlet cell and the rodlet cell's apparent involvement in the fight against parasites are both characters shared with the eosinophils of mammalian blood, and the frontiers in the latter fight are at epithelial surfaces.…”