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Coelomocytes of Nereis diversicolor synthesize and secrete vitellogenin in vitro. Using a monoclonal antibody which specifically recognized vitellogenin, we showed by immunocytochemistry that among the coelomocytes only a subpopulation, called eleocytes, countained vitellogenin. These results assert that eleocytes are the vitellogenin producing cells in nereids.

The presence in the marine worm Nereis diversicolor of a low molecular mass protein with the capacity to bind cadmium has been previously demonstrated [5]. Poly(A) + -mRNA were extracted from coelomocytes of Nereis diversicolor and were translated either in vitro , using a rabbit reticulocyte lysate, or in vivo into Xenopus laevis oocytes. Analysis of synthesized polypeptides by enzyme-linked immunosorbent assay (ELISA) and by Western blotting, using a specific monoclonal anti-MP II antibody, showed that this metalloprotein was translated both in in vitro and in vivo translation systems, with an apparent molecular mass of 11–13 kDa. Two other products, with 26.5 and 28 kDa molecular mass, cross-reacted with the monoclonal anti-MP II antibodies. The present work confirms that coelomocytes are sites of important synthesis of MP II-mRNA.

International audience; Incubation of mouse thymocytes with 10 μM monensin for 1 hour induces morphological alterations characterized by the extensive dilatation and vacuolization of the Golgi complex. This effect is used to study the transport and utilization of labelled sugar nucleotides into intracellular vesicles by using thymocytes whose plasma membrane has been permeabilized by ammonium chloride treatment. It is demonstrated that monensin stimulates the incorporation of labelled sialyl, fucosyl, galactosyl, and N-acetylglucosaminyl residues. This enhanced incorporation is not due to a direct effect of monensin on glycosyltransferase activities themselves but is a consequence of a higher entry and accumulation of labelled sugar nucleotides in the dilated vesicles.