Cytochemical Localisations and Ultrastructure in the Fertilized Unsegmented Egg of Paracentrotus lividus

Abstract

Fertilized, but still unsegmented, eggs of the sea urchin Paracentrotus llvidus have been centrifugated at 30,000 gravity. A comparison has been made between the cytochemical reactions of the different layers (RNA, polysaccharides, acid phosphatase) and the fine structure as shown in thin sections studied with the electron microscope.

Fine Structure of Annulate Lamellae

“…Merriam (21) has pointed out that annulate lamellae in sand dollar oocytes have a high intrinsic density which does not disappear when the section is bleached with hydrogen peroxide, and hence, they react to the treatment in the same way as the 150 A particles of the heavy bodies. Several studies (1,11,28) on various sea urchin oocytes have shown that annulate lamellae may be associated with masses of ribonucleoprotein; the latter probably are derived from the nucleolar material of the nucleus (1). Examples of annulate lamellae that are continuous at their ends with granular endoplasmic reticulum are numerous (4, 6-10, 13, 15, 17, 18, 28, 30-32).…”

Intranuclear and Cytoplasmic Annulate Lamellae in Tunicate Oocytes

“…The presence of ribosomes associated with the annulate lamellae in tunicate oocytes might warrant the assumption that these lamellae represent a specialized form of the endoplasmic reticulum in addition to the many rough-surfaced vesicles present in the ooplasm. However, the structural differences between the granular endoplasmic reticulum and annulate lamellae may also suggest functional differences between the two systems which, in some cells, are observed to be continuous (Rebhun, 1961). Certainly, differences in the physical nature and viscosity of the materials associated with the annulate lamellae as compared to the vesicular endoplasmic reticulum are indicated.…”

“…In some cells, ribosomes appear to be associated with annulate lamellae in the cytoplasm (Afzelius, 1957;Merriam, 1959;Kessel, 1964 b) while, in other instances, riboncleoprotein particles have not been observed to be associated with them (Rebhun, 1956;Ruthmann, 1958). The presence of ribosomes associated with the annulate lamellae in tunicate oocytes might warrant the assumption that these lamellae represent a specialized form of the endoplasmic reticulum in addition to the many rough-surfaced vesicles present in the ooplasm.…”

“…Few lamellar elements of the endoplasmic reticulum appear in the developing oocytes, but, when present, they are observed in the very small oocyte before any indication of yolk deposition. The predominantly vesicular form of the endoplasmic reticulum in the tunicate oocyte is unlike the lamellar or reticular form typically present in many somatic cells (Porter, 1961;Fawcett, 1961;Palade, 1956) and the well developed system of endoplasmic reticulum present in the crayfish oocyte (Beams and .…”

“…Annulate lamellae have been observed of late in the cytoplasm of a considerable variety of cell types, a feature which would tend to suggest that these structures perhaps have a more important role in the activity of cells possessing them than was formerly supposed. Annulate lamellae are commonly found in the cytoplasm of both invertebrate and vertebrate germ cells (Afzelius, 1957;Palade, 1955;Swift, 1956;Rebhun, 1956Rebhun, , 1961Ruthmann, 1958;King and Devine, 1958;Pasteels, Castiaux, and Vandermurssche, 1958;Merriam, 1959;Okada and Waddington, 1959;Kane, 1960;Wischnitzer, 1960;Barer et al, 1960;Gross et al, 1960;Kaye et al, 1961;Mahowald, 1962Mahowald, , 1963Balinsky and Devis, 1963;Kessel, 1963 a, b). However, the lamellae have also been observed in somatic cells (Swift, 1956;Ross, 1962;Harrison, 1962) as well as in tumor or cancer cells of various kinds (Schulz, 1957;Wessel and Bernhard, 1957;Binggeli, 1959).…”