Behaviour of annulate lamellae during the maturation of oocytes in the newt, Cynops pyrrhogaster

Development ◽  
1982 ◽  
Vol 70 (1) ◽  
pp. 153-169
Author(s):  
Hiroshi Imoh

The distribution of annulate lamellae, electron-dense masses, rough endoplasmic reticulum, and Golgi complexes in longitudinal sections of newt oocytes at several stages of progesteroneinduced maturation was recorded with an electron microscope equipped with a drawing device. Annulate lamellae in full-grown oocytes occur in close contact with electron-dense masses and the nuclear envelope and elsewhere. Stacks of annulate lamellae increase in number for 6 h after progesterone treatment. Meanwhile, they segregate into three groups. The largest group, comprising about 75% of total stacks, forms a row parallel to and just beneath the oocyte cortex of both the animal and vegetal hemispheres, a second group is distributed in the middle area of the vegetal hemisphere, and a third group appears near the yolk-free cytoplasm formed at the vegetal side of the germinal vesicle during the maturation. About 6 h after progesterone treatment the annulate lamellae begin to disappear at their places of localization and none is found a few hours after germinal vesicle breakdown. No immediate fine-structural change in the cortical area follows the disappearance of subcortical annulate lamellae. The possible origins and fates of annulate lamellae in the maturing newt oocytes are discussed.

1994 ◽  
Vol 107 (7) ◽  
pp. 1797-1805
Author(s):  
M. Terasaki

The starfish oocyte is relatively clear optically, and its nucleus, termed the germinal vesicle, is large. These characteristics allowed studies by confocal microscopy of germinal vesicle breakdown during maturation in living oocytes. Three fluorescent probes for cytoplasmic components were used: fluorescein 70 kDa dextran, which does not cross the nuclear pore of immature oocytes and probably behaves in the same way as soluble cytosolic proteins, YOYO-1, which was used to localize ribosomes, and DiI which labels the nuclear envelope and endoplasmic reticulum. The first change observable by transmitted light microscopy during maturation is a wrinkling of the germinal vesicle envelope. Several minutes before the wrinkling, the 70 kDa dextran began to enter the germinal vesicle; the ribosomes did not enter during this period. The dextran is likely to be passing through nuclear pores whose size limit has increased but which still exclude ribosomes. At the time of the wrinkling of the germinal vesicle envelope, both 70 kDa dextran and ribosomes entered as a massive wave. The characteristics of this entry indicate that the permeability barrier of the nuclear envelope bilayer has been disrupted. The disruption of the permeability barrier occurred in a local region rather than around the entire periphery. Also, the disruption was observed more often on the animal pole side of the germinal vesicle (26/34 oocytes). The endoplasmic reticulum entered the nuclear region more slowly. Cytochalasin B inhibited this movement and also inhibited characteristic endoplasmic reticulum movements seen at high magnification. The effects of cytochalasin indicate that mixing of endoplasmic reticulum with nuclear space is an active process involving actin filaments.


1972 ◽  
Vol 55 (3) ◽  
pp. 533-541 ◽  
Author(s):  
Bela J. Gulyas

The formation of the blastomere nucleus was examined in the rabbit zygote with the electron microscope. In late anaphase the chromosomes are bare and vesicles of the smooth endoplasmic reticulum are numerous in the vicinity of the chromosomes. In early telophase individual chromosomes attain their own nuclear envelope and they are called karyomeres. The envelope of the karyomeres contains small gaps within it at several places where the chromatin is exposed to the cytoplasm. Nuclear pores are also observed. In the cytoplasm short annulate lamellae appear adjacent to the karyomeres, and clusters of punctate substance are also present. From early telophase onward the karyomeres extend pseudopod-like structures, called karyopods, which extend toward other karyomeres or karyopods, and consequently fuse together and serve as chromosomal bridges. Eventually all of the karyomeres fuse into a dense nucleus and decondensation of the chromosomes occurs.


1965 ◽  
Vol 24 (3) ◽  
pp. 471-487 ◽  
Author(s):  
R. G. Kessel

Electron microscope studies were made on various tunicate oocytes at different stages of growth and development. Both the inner and outer lamellae of the perforated nuclear envelope demonstrate considerable blebbing activity. The blebs of the inner lamella detach into the nucleoplasm where they undergo a special type of fusion process resulting in the formation of numerous, usually single, differentiated annulate lamellae of various lengths. The blebbing of the outer layer of the nuclear envelope contributes to the vesicular and granular endoplasmic reticulum characteristically present in the ooplasm and perhaps to the differentiation of cytoplasmic annulate lamellae as well. Cytoplasmic stacks of annulate lamellae frequently have ribosomes associated with them. In addition, granular accumulations are sometimes observed around or between the annuli. The morphological evidence suggests that, at least in many cases, the annuli in the annulate lamellae are patent.


1959 ◽  
Vol 5 (3) ◽  
pp. 501-506 ◽  
Author(s):  
W. Gordon Whaley ◽  
Hilton H. Mollenhauer ◽  
Joyce E. Kephart

Maize root tips were fixed in potassium permanganate, embedded in epoxy resin, sectioned to show silver interference color, and studied with the electron microscope. All the cells were seen to contain an endoplasmic reticulum and apparently independent Golgi structures. The endoplasmic reticulum is demonstrated as a membrane-bounded, vesicular structure comparable in many aspects to that of several types of animal cells. With the treatment used here the membranes appear smooth surfaced. The endoplasmic reticulum is continuous with the nuclear envelope and, by contact at least, with structures passing through the cell wall. The nuclear envelope is characterized by discontinuities, as previously reported for animal cells. The reticula of adjacent cells seem to be in contact at or through the plasmodesmata. Because of these contacts the endoplasmic reticulum of a given cell appears to be part of an intercellular system. The Golgi structures appear as stacks of platelet-vesicles which apparently may, under certain conditions, produce small vesicles around their edges. Their form changes markedly with development of the cell.


Development ◽  
1968 ◽  
Vol 19 (3) ◽  
pp. 319-326
Author(s):  
Lennart Nicander ◽  
Björn A. Afzelius ◽  
Inger Sjödén

Fertilization is accompanied by changes in the structure of the egg cytoplasm (cf. Rothschild, 1958; Raven, 1961). At the level of fine structure such changes have mainly been studied in some marine invertebrates with small eggs that can easily be fertilized in vitro (Pasteels & de Harven, 1963; Schäfer, 1966). Vertebrate eggs are less favourable in this respect, but electron microscope studies have been made on eggs of mammals (Fléchon, 1966; Zamboni & Mastroianni, 1966; Zamboni, Mishell, Bell & Baca, 1966) and Xenopus (van Gansen, 1966). Changes generally observed soon after fertilization include the formation of polysomes or an increase in their number, a hypertrophy of the Golgi complexes, and the appearance of granulated endoplasmic reticulum and annulate lamellae. Afzelius (1957) observed the dispersal of mitochondria in fertilized sea-urchin eggs. Pasteels & de Harven (1963) reported that the structure and distribution of cytoplasmic organelles in eggs of the bivalve mollusc, Barnea Candida, are not altered by fertilization.


1968 ◽  
Vol 37 (2) ◽  
pp. 540-550 ◽  
Author(s):  
John W. Everingham

Oocytes of four species of ascidians were examined with the electron microscope. Prior to fixation, oocytes were subjected to centrifugal forces of 10–15,000 g for 5–10 min and were compared with uncentrifuged oocytes. Intranuclear annulate lamellae (IAL) are distributed uniformly around the periphery of the nucleus of the uncentrifuged oocyte. Centrifugation produces a marked flattening of the oocyte nucleus, migration of nucleoli to the centrifugal end, and often a condensation of the nucleoplasm at the centrifugal end. In contrast, the distribution of IAL is unchanged by centrifugation. Furthermore, numerous IAL profiles appear to be touching the nuclear envelope, and, in a few of these, direct continuity of the IAL with the nuclear envelope is demonstrated.


2015 ◽  
Vol 48 (3) ◽  
pp. 381-389
Author(s):  
J. A. Tarkowska

Dividing endosperm cells of <i>Haemanthus katherinae</i> Bak., treated with 0.025 per cent aqueous solution of a mixture of glycosides from <i>Nerium oleander</i> were examined in vitro in the light and in the electron microscope. A high hypertrophy of endoplasmic reticulum was noted. In prometaphase and metaphase, after treatment for about l h 45 min there appeared very narrow cisternae forming various configurations, frequently in parallel and concentric arrangement. On the membranes of these cisternae there are formed dark areas interpreted as pores characteristic for nuclear envelopes, this indicating that at least part of the two-membrane structures transforms to the nuclear envelope. The formation of the new nuclear envelope pre-maturely and apparently in excess is discussed.


Author(s):  
Z. Fumagalli ◽  
P. Motta ◽  
S. Calvieri

The presence of smooth muscular cells was demonstrated with the electron microscope in different areas of the ovary of cats, mice and rabbits. The myocytes were arranged in fascicles, small groups, or most frequently appeared isolated. They were scattered in the ovarian stroma, related to the interstitial cells, in the periphery of the corpora lutea (rarely between luteal cells) in the middle of the gland. Smooth muscular cells were seldom observed between cells of the theca interna and externa of developing follicles and in the middle of atresic follicles. Some smooth muscular cells were found in the cortical area of the ovaries.Each smooth muscular cell showed typical filaments, free ribosomes, lipid droplets and at times glycogen particles. Mitochondria were vesicular; the (Golgi) vesicular complex was often related to two centrioles (frequently in a process of ciliogenesis). The granular endoplasmic reticulum was moderately developed. The plasma membrane presented invaginations and micropinocytotic vesicles as well as tight junctions between adjacent cells. The nucleus was elongated and its envelope formed wide perinuclear cisternae.


1979 ◽  
Vol 82 (1) ◽  
pp. 264-277 ◽  
Author(s):  
R M Ezzell ◽  
C M Szego

Maturation of the mammalian oocyte is characterized in part by dissolution of the nuclear envelope, or germinal vesicle breakdown (GVB). By fluorescence microscopy after vital uptake of acridine orange (AO), redistribution and perinuclear accumulation of organelles corresponding to lysosomes occur before GVB in rat oocytes undergoing meiotic maturation in vitro. In follicle-enclosed oocytes explanted during the preovulatory gonadotropin surge (GS) and individually cultured as such in chemically defined medium at approximately 22 degrees C, lysosomes aggregated into disperse clusters after 30 min; by 60 min, perinuclear concentration of lysosomes and their essential disappearance from the cortical ooplasm were observed. GVB occurred within 120 min. In contrast, follicle-enclosed oocytes explanted before the GS displayed a generally homogeneous distribution of lysosomes and intact GV for up to 5 h in culture. In oocytes aspirated from follicles before the GS, partially denuded of granulosa cells, and cultivated without added hormone, most lysosomes concentrated around the GV within 60 min, with GVB occurring generally by 120 min. Luteinizing hormone (LH) added in vitro to the isolated preparation at 3 or 30 x 10(-8) M sharply accelerated these events. The effects of LH, not seen with 1.5 x 10(-8) M hormone, were blocked by anti-LH IgG. Up to 60 x 10(-8) M follicle-stimulating hormone or 80 x 10(-8) M prolactin were ineffective in accelerating lysosome redistribution or GVB. After GVB, lysosomes became once again uniformly dispersed and unresponsive, even to 60 x 10(-8) M added LH, a finding consistent with tachyphylaxis of target cells by independent criteria. The present data, all statistically significant at P less than 0.05, demonstrate that mobilization of lysosomes before GVB is a specific response to factors that promote resumption of meiotic maturation of rat oocytes.


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