Biomedical subjects
Publications and source records attributed to A B Dutkowski.
Significant retardation of G. mellonella development was induced by reserpine injected to the last instar larvae in doses having a long-lasting effect on the neurosecretory system.
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This study concerns the influence of reserpine on the fine structure of peptidergic neurosecretory cells in the pars intercerebralis of Galleria mellonella, and of neurons containing smaller dense-cored vesicles (presumed to be aminergic) localized in the same area of the brain. The drug, administered in doses of 125 microgram and 250 microgram per g of insect body weight, reduces both the amount and the electron opacity of the dense-cored vesicles with a diameter of 60--80 nm in the neuronal perikarya as well as their terminals. Simultaneously, this treatment evokes an abnormal accumulation of secretory granules within the perikarya of peptidergic neurosecretory cells belonging to three types. This accumulation of secretory material is followed by some changes in the fine structure of these cells. One (fourth) type of neurosecretory cells seems to be insensitive to reserpine action. Participation of the aminergic system in the regulation of the secretory activity of some populations of peptidergic neurosecretory neurons of the insect brain is postulated.
The fat body lobes of Galleria mellonella are surrounded by basement membrane - a fine granular layer of connective tissue. This membrane has an affinity for ruthernium red. The results obtained after treatment of the fat body with neuraminidase, hyaluronidase, phospholipase C and proteolytic enzymes suggest that glycoproteins and phospholipoproteins are constituents of this basement membrane. The basement membrane also has the ability to bind concanavalin A-peroxidase, which is associated with the presence of mannoside residues.
The outer surface of the neural lamella, the connective tissue ensheathing the brain, shows the ability to bind ruthenium red in the wax moth larva. Ruthenium red-positive material is sensitive to neuraminidase, hyaluronidase and to some extent to phospholipase C, what suggests that the negative charge on the external surface of the neural lamella depends on the presence of the anionic groups of sialic and hyaluronic acids and phospholipids.
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Whole ovaries of the sawfly, Acantholyda nemoralis Thoms., Tenthredinidae, Hymenoptera, were cultivated by the organ culture technique of Fell in the medium of Jones and Cunningham modified by doubling the contents of salts, sugars and lactalbumin hydrolysate and supplemented with an addition of folate. In the experimental conditions the sawfly ovary survived for several days showing mitoses in the follicular epithelium. In some of the nurse cell nuclei of the cultured ovaries nucleolus-like structures developed which showed a positive reaction to the Hamm test for viral polyhedra. Formation of these structures was stimulated by amethopterin. Electron microscopical examination revealed that these structures were not viral polyhedra but enlarged nucleoli whose modified ultrastructure differed considerably from that of the nucleoli of cells of trophic ovaries in normally developing insects. Amethopterin appears to induce enlargement of the granules of the granular component of nucleolonema, probably due to disturbance in RNA biosynthesis. The positive Hamm test obtained in the nucleoli shows that this test cannot be regarded as specific for nuclear polyhedra.
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