An electron microscope study of the nuclear envelope of amphibian oocytes

Structures and Functions of the Nuclear Envelope

“…16,18c,19B; the "fingerlike projections" of Watson, 1959; the "Zipfel", "projecting tips" or "tiplike projections" of Franke, 1966aFranke, , b, 1967aFranke, , b, 1970aFranke and Scheer, 1970a; the "peripheral granules" of Northcote, 1970, 1971; the "traversing fibers" of Maul, 1971a; the "claws" of Engelhardt and Pusa, 1972). We think that these projections are identical to the structures which have been envisaged as tubules or cylinders by some earlier authors (Wischnitzer, 1958;Vivier, 1967;Abelson and Smith, 1970;Blackburn, 1971). These projecting clumps can be so well developed that they seem to fill, especially in thick or "off pore center" sections, almost the entire pore interior, and to constitute a compound plug-the "diaphragm" of the literature (Afzelius, 1955;M erri am, 1961; for detailed discussion see Stevens and Andre, 1969;.…”

“…22; Franke, 1966aFranke and Scheer, 1970a;Roberts and Northcote, 1970; these models were substantially confirmed by LaCour andWells, 1972, andSpeth, 1972). These models differ, however, from those of Dawson et al (1955), Wischnitzer (1958), NjI}rrevang (1965), Sichel (1966, Vivier (1967), Abelson and Fig. 22 Earlier (a;from Franke, 1966a) and recent model views of the pore complex: The pore fenestrae are associated with annular granules.…”

“…Afzelius, 1955;Dawson et al, 1955;Andre and Rouiller, 1956;Wischnitzer, 1958Wischnitzer, , 1960Watson;Merriam, 1961;Gall, 1964;N~r revang, 1965;Franke, 1966aFranke, , b, 1970aSichel, 1966;Vivier, 1967;Gouranton, 1969;Stevens and Andre, 1969;Abelson and Smith, 1970;Franke and Scheer, 1970a;Picheral, 1970;Northcote, 1970, 1971;Blackburn, 1971;Engelhardt and Pusa, 1972;LaCour and Wells, 1972;Wunderlich and Speth, 1972;Faberge, 1973). Recently, however, the majority of groups working in this field have reached essential agreement.…”

The Nuclear Envelope after KMnO4 Fixation

“…One can reconcile the differences between OsO4-and KMnO4-fixed material in basically two ways: (1) One can assume that an annulus is a short cylindrical tube (1,14) or a circlet of granules (7,10,13) fitted into or surrounding a pore. KMnOa fixation preserves the membranous parts of the envelope, but permits complete dissolution of the annuli, whereas OsO4 preserves both membranes and annuli.…”

Increased Numbers of Annulate Lamellae in Myocardium of Chick Embryos Incubated at Abnormal Temperatures

“…These microcylinders or subannuli have been previously observed (Merriam, 1958(Merriam, , 1959Ross, 1962;Chambers and Weiser, 1964 b). Wischnitzer (1958) reported that an average of 8 microcylinders form each annulus of the nuclear envelope.…”