Ultrastructural immunocytochemical localization of vitellogenin in the fat body of the blowfly, Calliphora vicina Rob.-Desv. (erythrocephala Meig.) by use of the unlabeled antibody-enzyme method

Abstract

The unlabeled antibody-enzyme method was used to demonstrate ultrastructurally the specific localization of vitellogenin in the fat body of Calliphora. In control flies the binding sites to vitellogenin were localized in secretory granules situated in the Golgi complex, and in larger bodies named composite secretory granules. These composite granules appear to be formed when a part of a Golgi complex containing secretory granules and a number of small vesicles become surrounded by a common membrane. Ovariectomized flies, which apparently do not produce secretory granules, exhibited no immunocytochemical staining. Ovariectomized flies in which the administration of ecdysterone induced formation of secretory granules, also revealed specific staining on these granules. This is the first ultrastructural evidence of: (a) the specific localization of vitellogenin in secretory granules of the fat body of an insect; (b) the relationship between the presence of the ovary, and of ecdysterone, and the synthesis of vitellogenin by the fat body.

Secretory and internalization pathways of mosquito yolk protein precursors

“…This observation is in agreement with numerous biochemical studies (reviewed in Kunkel and Nordin 1985;Kanost et al 1990;Raikhel and Dhadialla 1992). Visualization of Vg in the fat body trophocytes has been previously performed for several insects by means of immunocytochemical techniques for fluorescent light microscopy (Tanaka and Yokizaki 1974) and electron microscopy (Couble et al 1979;Thomsen et al 1980;Mazzini et al 1989) and is particularly detailed for A. aegypti (Raikhel and Lea 1983;Raikhel 1986a, b;1987).…”

Considerations on some cytological and ultrastructural observations on fat cells ofDaphnia(Crustacea, Cladocera)

“…The extraovaric synthesis of proteic yolk precursor, named vitellogenin, is fairly common in Arthropods. In Daphnia the most likely site of vitellogenin synthesis can be found in the fat cells, first of all for the above-mentioned functional relations between fat cells and ovaries, secondly because it has been shown that also in insects (Chen, et al, 1979;Engelmann, 1979;Thomsen et al, 1980;Zhai et al, 1984), in amphipods Meusy et al, 1983) and isopods (Picaud & Souty, 1980;Picaud, 1980;Souty & Picaud, 1981) the fat cells synthesize vitellogenin. In the stomatopods, vitellogenin is synthesized in the hepatopancreas (Ferrero, Savoini and Marzari, personal communication); however this organ is lacking in Cladocera.…”

Ultrastructural indications for autosynthetic proteinaceous yolk formation in amphibian oocytes

“…More detailed investigations in this direction will be necessary, e.g. with the antibody-enzyme method, which could help to detect vitellogenin production within Cell organelles of the oocyte (Thompson et al 1980). Giorgi et al (1976) observed that Golgi material seems to be incorporated into the surface membrane, Experientia 38 (1982), Birkhauser Verlag , CH-4010 Basel/Switzerland the oolemma.…”