Étude des protéines vitellines de l'hémolymphe et de l'ovaire chez le Crustacé Décapode Carcinus maenas; incidence du parasite Sacculina carcini (Crustacé Rhizocéphale)

Abstract

We have performed electrophoretic, immunochemical, and immunoautoradiographic analyses of vitellin proteins from the ovary and hemolymph of healthy crabs of the species Carcinus maenas during vitellogenesis. The same study was performed in parasitized crabs and in the parasite, Sacculina carcini. In unparasitized crabs, there are two vitellin proteins in the ovary. They are immunologically similar, but their electrophoretic mobility is different. One (primary vitellin) is synthesized in the ovary throughout the ovarian cycle. The other (secondary vitellin) exists in the ovary only during secondary vitellogenesis and is partially of endogenous origin. From primary vitellogenesis, we observed in the hemolymph only one vitellogenic protein, homologous to secondary vitellin, of which it is the exogenous precursor. The ovary and hemolymph of parasitized crabs contain the same proteins as those of unparasitized females during primary vitellogenesis. The large quantities of these proteins, observed when the ovarian development is stopped, suggest inhibition of the control of their synthesis and of absorption of the vitellogenin by the gonad. Secondary vitellin was never observed. Sacculina has two vitellin proteins present in the ovary, integument, and hemolymph. These proteins show no electrophoretic or immunochemical similarity to those from the host. At least one has a dual origin, exogenous and endogenous. The roots of the parasite contain neither the crab's vitellin proteins nor those from Sacculina, and do not seem to be a site of transfer or of synthesis for these substances.