Production of specific-protein secretion granules by fat body cells of the blowfly, Calliphora erythrocephala. Substitution of an ovarian key factor by beta-ecdysone

Ultrastructural changes in the fat body of desert locust, Schistocerca gregaria (Orthoptera: Acrididae) treated with zinc chromium oxide nanostructures via chemical co-precipitation approach

The present work aims to investigate the ultrastructural changes in the fat body of fifth instar nymphs Schistocerca gregaria (Orthoptera: Acrididae) treated with zinc chromium oxide (ZnCrO). The nanoparticles (NPs) were prepared by co-precipitation route and characterized using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The ZnCrO NPs exhibited polycrystalline hexagonal structure, composed of spherical-hexagonal shapes with an average size ~ 25 nm. Besides, the UV-Vis spectrophotometer (Jasco-V-570) was utilized for optical measurements. The energy gap [Formula: see text] was estimated from the transmittance (T%) and reflectance (R%) spectra through the range of 3.307-3.840 eV. In biological sections, S. gregaria 5th instar nymphs, TEM images demonstrated that the fat body was strongly impacted with the concentration 2 mg NPs result in great agglomeration of chromatin in the nucleus as well as haemoglobin cells (HGCs) pierced with malformed trachea (Tr) at 5th and 7th days post treatment. The obtained results indicated a positive action of the prepared nanomaterial on Schistocerca gregaria fat body organelles.

Cytochemistry of fat body trophocytes and ovaries of workers and queens of Melipona quadrifasciata anthidioides (Hymenoptera: Apidae: Meliponini) during vitellogenesis

The fat body (FB) of insects is where yolk proteins are synthesized. Therefore, relationships between the FB and oogenesis were studied in nurse workers, virgins, and physogastric queens of Melipona quadrifasciata anthidioides, a stingless bee in which the workers produce and lay eggs while provisioning brood cells. The relationships between FB and oogenesis, as well as the routes of materials from hemolymph to the oocytes, were studied through the cytochemical detection of lipids by osmium imidazole (OI), carbohydrates by ruthenium red (RR) and basic proteins by ammoniacal silver (AS). The results show differences in the presence of the studied materials in FB trophocytes and ovary of the classes of females studied and oogenesis phases. Material that tested positive for the treatments was detected among the classes of individuals studied in both, trophocytes and oocytes, and in the route of those materials from hemolymph to the oocytes. The differences found among the individual classes indicate relationships with the nutrition and adaptation to the parsimonious use of nutrients in the metabolism of reproduction.

Previtellogenic development and vitellogenin synthesis in the fat body of a mosquito: an ultrastructural and immunocytochemical study

We describe two phases, previtellogenic and vitellogenic, in the activity of the trophocytes in the fat body of the mosquito Aedes aegypti. The previtellogenic phase, leading to trophocyte competence to synthesize vitellogenin (Vg), occurred during the first 3 days after eclosion. This phase was characterized by enlargement and activation of the nucleoli, proliferation of ribosomes and rough endoplasmic reticulum (RER), development of Golgi complexes, and extensive invaginations of the plasma membrane. During the vitellogenic phase, initiated by a blood meal, Vg was first detected, by immunofluorescence, 1 hr after feeding. The intensity of the immunoreaction increased for the next 24 hr, was declining at 30 hr, and had disappeared by 48 hr. Vg synthesis was characterized ultrastructurally by the enlargement of the RER and the formation of dense secretion granules in Golgi complexes. These secretion granules were two to three times larger at the peak of Vg synthesis than at the beginning. The granules discharged their contents by exocytosis. Two electron microscopical immunocytochemical methods, immunoferritin and peroxidase-antiperoxidase, confirmed this pathway of Vg processing. For the first 12 hr after feeding. Vg synthetic organelles proliferated and the active nucleoli were multilobed; thereafter, while Vg synthesis continued, the nucleoli began to regress into compact bodies. Termination of Vg synthesis was marked by autophagical degradation of Vg synthetic and processing organelles.

Moulting hormone, juvenile hormone and the ultrastructure of the fat body of adult Sarcophaga bullata (Diptera)

In the ovoviviparous fly, Sarcophaga bullata, vitellogenesis in cyclic; a process reflected in ultrastructural changes in the fat body cells and oenocytes. At eclosion the larval fat body has not yet completely disappeared. During vitellogenesis the fat body cells are specialized for intensive protein synthesis showing a very extensive RER and numerous invaginations of the plasma membrane. These features disappear when the eggs descend into the oviducts to complete embryogenesis. The predominant feature of the oenocytes is their very prominent SER. The fat body cells of the males are never as specialized for protein synthesis as those of the females. Feeding of ecdysterone to males for 3 or more days induces a rather extensive subcellular apparatus for protein synthesis, i.e., invaginations of the plasma membrane and an extensive RER. Juvenile hormone is completely ineffective in this respect. Both ecdysterone and juvenile hormone have pronounced but different effects on the oenocytes of males.