Summary
In Nassarius reticulatus the nuclei and nucleoli undergo important morphological changes from the zygote to the 16-cell stage. In the zygote and in the trefoil (2-cell) and 4-cell stage, several agranular, fibrillar nucleolus-like bodies 1 μm diameter are present in the interphase nucleus. Granular nucleoli first appear at the 8-cell stage. These nucleoli have fibrillar and granular regions. The granular regions are made up predominantly of ribosome-like osmiophilic granules. From the 16 and 32-cell stage onwards, the one or two spherical nucleoli of each nucleus measure 2.5 μm in diameter and show a concentric organization with a very dense central region surrounded by a broad peripheral zone containing numerous granules, possibly of ribonucleoprotein. At the same time the number of ribosome-like particles increase in the karyoplasm and that of ribosomes in the cytoplasm. These findings are surprising because in eggs with radial cleavage, which have been subjected to more detailed analysis, the first granular nucleoli appear after the end of the cleavage, at the blastula or gastrula stage. The early appearance of granular nucleoli which seem to be characteristic of several eggs with spiral cleavage is discussed in connection with biochemical data on RNA-synthesis.
Similar content being viewed by others
References
Afzelius, B.A.: Electron microscopy on the basophilic structures of the sea urchin egg. Z. Zellforsch. 45, 660–675 (1957)
Biggelaar, J.A.M. van, den: RNA synthesis during cleavage of the Lymnaea egg. Exp. Cell Res. 67, 207–210
Bottke, W.: Lampenbürstenchromosomen und Amphinukleolen in Oocytenkernen der Schnecke Bithynia tentaculata L. Chromosoma (Berl.) 42, 175–190 (1973)
Cather, J.N.: A time schedule of the meiotic and early mitotic stages of Ilyanassa. Caryologia 16, 663–670 (1963)
Clement, A.C.: Ilyanassa. In: G. Reverberi (ed.), Experimental embryology of marine and freshwater invertebrates, pp. 188–214. Amsterdam-London: (1971)
Collier, J.R.: Nucleic acid and protein metabolism of the Ilyanassa embryo. Exp. Cell Res. 24, 320–326 (1961a)
Collier, J.R.: The effect of removing the polar lobe on the protein synthesis of the embryo of Ilyanassa obsolete. Acta Embryol. Morph. exp. 4, 70–76, (1961b)
Collier, J.R.: The incorporation of uridine into the deoxyribonucleic acid of the Ilyanassa embryo. Exp. Cell Res. 32, 442–447 (1963)
Collier, J.R.: Ribonucleic acids of the Ilyanassa Embryo. Science 147, 150–151 (1965)
Collier, J.R., Schwartz, R.: Protein synthesis during Ilyanassa embryogenesis. Exp. Cell Res. 54, 403–406 (1969)
Harris, P.J.: Nucleolus-like bodies in sea urchin eggs. Amer. Zool. 7, 753 (1967)
Kessel, R.G.: Some observations on the ultrastructure of the oocyte of Thyone briareus with special reference to the relationship of the Golgi complex and endoplasmic reticulum in the formation of yolk. J. Ultrastruct. Res. 16, 305–319 (1966)
Kessel, R.G.: An electron microscope study of differentiation and growth in oocytes of Ophioderma panamensis. J. Ultrastruct. Res. 22, 63–89 (1968)
Meisenheimer, J.: Entwicklungsgeschichte von Limax maximus L. I. Furchung und Keimblätterbildung. Z. wiss. Zool. 62, 415–468 (1896)
Millonig, G.: The structural changes of the nucleolus during oogenesis and embryogenesis of Arbacia lixula. J. Cell Biol. 35, 177A (1967a)
Millonig, G.: The morphological changes of the nucleoli during oogenesis and embryogenesis. Atti Ace. Naz. Lincei. Cl. Sci. Fis. Mat. Nat. 104, 113–115 (1967b)
Millonig, G., Bosco, M., Giambertone, L.: Fine structure analysis of oogenesis in sea urchins. J. exp. Zool. 169, 293–324 (1968)
Raven, Chr. P.: Morphogenesis. London: Pergamon Press 1. 311 (1958)
Schmekel, L., Fioroni, P.: The ultrastructure of the yolk nucleus during early cleavage of Nassarius reticulatus L. (Gastropoda, Prosobranchia). Cell Tiss. Res. 153, 79–88 (1974)
Schmekel, I., Fioroni, P.: Cell differentiation during early development of Nassarius reticulatus L. (Gastropoda, Prosobranchia). I. Zygote to 16-cell stage. Cell Tiss. Res. 159, 503–522 (1975)
Taylor, G.T., Anderson, E.: Cytochemical and fine structural analysis of oogenesis in the Gastropod Ilyanassa obsoleta. J. Morph. 129, 211–248 (1969)
Author information
Authors and Affiliations
Additional information
This investigation was supported by the Deutsche Forschungsgemeinschaft and the Stiftung Volkswagenwerk
We wish to thank Mrs. C. Mehlis for valuable technical assistance and Prof. J. Bergerard for the excellent working conditions at the Station biologique at Roscoff (France)
Rights and permissions
About this article
Cite this article
Schmekel, L., Fioroni, P. Cell differentiation during early development of Nassarius reticulatus L. (Gastropoda, prosobranchia). Cell Tissue Res. 168, 361–371 (1976). https://doi.org/10.1007/BF00215313
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00215313