Annulate lamellae and "yolk nuclei" in oocytes of the dragonfly, Libellula pulchella

Annulated membranes in the form of single and short lamellae are present adjacent to and parallel to the nuclear envelope in oogonia and early oocyte (synaptene) stages of the dragonfly, Libellula pulchella. These solitary and short annulate lamellae are usually continuous with long, part rough- and part smooth-surfaced cisternae which extend into more distal areas of the oogonial ooplasm. These particular annulate lamellae then either disappear or decrease in number to be replaced by a much more extensive system of annulate lamellae in the cortical ooplasm of previtellogenic oocytes. The differentiation of extensive stacks of annulate lamellae is consistently observed to be restricted to large cytoplasmic areas of considerable electron density. These cytoplasmic regions consist of material which stains basophilic and contains RNA but differs structurally from the large number of ribosomes which surround the dense masses. The cytoplasmic dense masses, in terms of their formation and staining reactions, are comparable to the "yolk nuclei" or "Balbiani bodies" described in insect oocytes in earlier studies. The results of the present study thus provide evidence that the appearance of cortical ooplasmic stacks of annulate lamellae in the dragonfly oocyte is specifically limited to cytoplasmic areas of high electron density which contain RNA but which do not have a ribosomal morphology.     

Differentiation of Acmaea digitalis oocytes with special reference to lipid-endoplasmic reticulum-annulate lamellae-polyribosome relationships

During initial stages of oogenesis, many nucleoli are adpressed to the inner membrane of the nuclear envelope. Small nucleolar fragments appear to traverse the pores of the nuclear envelope and accumulate in the perinuclear ooplasm as fibrogranular bodies. Mitochondria become closely associated with some of the fibrogranular bodies. In addition to ribosomes and polyribosomes that are present in small oocytes, lamellae of rough-surfaced endoplasmic reticulum (rER) increase greatly in number during early stages of differentiation. Some individual lamellae are attached at their ends to the outer membrane of the nuclear envelope. Many parallel lamellae of rER are then encountered as well as numerous circular profiles consisting of concentric loops of rER. Soon after the differentiation of the extensive system of rER, lipid droplets or spheres appear in the ooplasm and they are initially surrounded by many circular, concentric lamellae of rER. Initially, the number of concentric lamellae of rER surrounding a lipid droplet may vary from less than a dozen to more than two dozen. During middle and late phases of vitellogenesis, most of the lipid spheres that comprise the most numerous and significant component of the yolk are surrounded by only one or two concentric lamellae of rER (in some cases the lamellae are part rough-surfaced and part smooth-surfaced). In addition, annulate lamellae are then observed to be associated with a portion of the lipid droplet surface. The number of annulate lamellae that extend focally from the lipid sphere distally into the cytoplasm is variable; often two or three to more than a dozen lamellae. Small granules, many of which range from 6 to 12 nm and thin fibrils (approximately 2–3 nm in width) may be associated with the annulate lamellae. In addition, polyribosomes frequently appear to be continuous with the pore-associated material of the annulate lamellae. The ends of some annulate lamellae may extend as lamellae of the rER. The morphologic relationships and relationships and variations observed between the lipid droplets, rER, annulate lamellae, and polyribosomes during lipidogenesis in this oocyte are interpreted to support a recent hypothesis (Kessel, 1981a,b) that the pores of annulate lamellae may be involved in some manner with the processing of ribosomal subunits or precursors into functioning polyribosomes, and that their appearance in specific association with the surface of many lipid spheres and rER in the oocyte late in vitellogenesis may be related to the formation of additional functional polyribosomes necessary to complete the final synthesis of many lipid droplets that are present in the ooplasm of the full-grown oocyte.     

Accumulation of Annulate Lamellae in the Subcortical Layer during Progesterone-induced Oocyte Maturation in Xenopus Laevis

Changes in the fine structure, the location and the number of stacks of annulate lamellae during progesterone-induced maturation of oocytes of Xenopus were determined by electron microscopy. longitudinal sections of full-grown oocytes, about 260 stacks of annulate lamellae were observed with marked concentration in the subcortical layer, particularly in the vegetal hemisphere. After exposure to. progesterone, annulate lamellae increased and accumulated further in the subcortical layer. A significant increase of annulate lamellae around the vegetal side of the germinal vesicle seen 3 h after progesterone application. In oocytes 6 h after progesterone application, an average of 320 stacks of annulate lamellae were seen in longitudinal sections and more than two-thirds of the pore complexes of annulate lamellae were localized in the subcortical layer less than 50 from the oocyte surface, the rest being distributed in the deeper ooplasm. At the time of ger- minal vesicle breakdown, all the annulate lamellae underwent complete decomposition. The results were discussed from the view point of comparative developmental biology.     

Differentiation and distribution of annulate lamellae in growing oocytes in the newt, Cynops pyrrhogaster

Stages of oocyte development in Cynops pyrrogaster are defined, and changes of annulate lamellae in their fine structure, number, sizes and locations during oogenesis are described. The results show that two different types of annulate lamellae occur during oogenesis. One type differentiates in or at the periphery of vesicle-rich cytoplasm at the early stages of vitellogenesis and increases in number and size. The maximum number of about 40 stacks per median section of oocyte is reached at the stage of complete differentiation of the animal and the vegetal hemispheres. In these growing oocytes, all the stacks show elongate appearances and tetragonal arrangements of annuli as common characteristics. A second type of stacks of annulate lamellae is added anew in full-grown oocytes, increasing the number of stacks per median section of the oocyte to about 90. The new stacks occur in close contact with electron-dense bodies in the cytoplasm and have a massive appearance and hexagonal array of annuli. It is suggested that they appear coincidentally with the onset of oocyte maturation. The possible significance of the observed results is discussed.     

Freeze-fracture analysis of structural reorganization during meiotic maturation in oocytes of Xenopus laevis

Summary During meiotic maturation, the cortex of oocytes of Xenopus laevis undergoes structural reorganization, visualized in this study by freeze-fracture electron microscopy. In the full-grown but immature oocyte, annulate lamellae are dispersed throughout the subcortex of the egg, 5 to 20 m from the plasma membrane. The annulate lamellae consist of well-organized stacks of membrane with visible pores. Stimulation of meiotic maturation by progesterone leads to disruption of the annulate lamellae and formation of an elaborate cortical endoplasmic reticulum which surrounds the cortical granules and intertwines throughout the cortex of the mature egg. Pore-like structures similar to those previously observed in the subcortical annulate lamellae are observed in the mature cortical endoplasmic reticulum. The cortical endoplasmic reticulum is often in close apposition with the plasma membrane and with membranes of cortical granules, but no junctions are visualized. This study provides further evidence that the cortical endoplasmic reticulum develops during progesterone-stimulated meiotic maturation in vitro, and that the annulate lamellae are precursors to the cortical endoplasmic reticulum.     

Fibrogranular Material,Annulate Lamellae and Microtubules During Spermiogenesis in Drosophila melanogaster

During spermiogenesis in Drosophila melanogaster, a “perinuclear plasm’ accumulates between the fenestrated portion of the nuclear envelope and an adjacent lamella of ER in the young spermatid. Microtubules appear within the perinuclear plasm and become especially concentrated in a nuclear concavity. Cytoplasmic pores are present locally within the lamella of ER. In addition, localized or discrete bodies composed of fibrogranular material become closely associated with single pore complexes in the lamella of ER. A close association exists between pore complexes (annulate lamellae), the small granular and fibrillar subunits of the fibrogranular bodies, polyribosomes and the nuclear-associated microtubules during much of spermiogenesis. While the fibrogranular material becomes less concentrated during spermiogenesis, the number of pore complexes in a single section increases such that two, three or even four short annulate lamellae are intercalated within many longitudinally oriented microtubules which are present in the furrow of the spermatid nucleus. Structural relationships observed between cytoplasmic pores (annulate lamellae), fibrogranular bodies, polyribosomes and microtubules are discussed in relation to information about the timing of RNA and protein synthesis. This study extends previous observations about the distribution and structural variations of annulate lamellae elsewhere in the spermatid cytoplasm.     

Intranuclear annulate lamellae in oocytes of the tunicate,Styela partita

Summary Intranuclear annulate lamellae have been observed with the electron microscope in oocytes of the tunicate, Styela partita. Morphological evidence suggests that the annulate lamellae may arise by a specialized fusion process of individual vesicles. Intranuclear vesicles appear to be formed, in time, before differentiated annulate lamellae. It is also suggested that the position and structure of an annulus is in large part determined by the fusion of the vesicles. An annulus may be present as soon as two vesicles have completed their fusion process. Finally, it is again suggested on the basis of morphological evidence that the intranuclear vesicles are derived by the blebbing activity of the inner layer of the nuclear envelope.This investigation was supported by grants (RG-9229, 9230) from the National Institutes of Health, Public Health Service. The electron microscope facilities used were also supported by a grant (GM-05479) from the National Institutes of Health to Professor H. W. Beams.     

金鱼卵母细胞发育过程中环孔片层的电镜观察

本文研究了环孔片层在金鱼卵母细胞发育过程中的一些形态变化。描述卵母细胞发育的五个阶段中每个阶段环礼片层的分布以及排列的情况。结果表明随着卵母细胞的生长,环孔片层的出现率和每束中片层的数目都逐渐增加。除了在卵原细胞以外,环礼片层一般都分布在远离细胞核的卵质中。尚观察到孔结合物质和片层间物质与多核蛋白体有联系。我们从观察结果推测金鱼卵母细胞的环孔片层可能是由粗面内质网衍生而成。     

Is the nuclear envelope a ‘generator’ of membrane?

Summary Early diplotene oocytes from Necturus maculosus ranging from 0.2 to 0.5 mm in diameter were examined by electron microscopy. In the smallest oocytes of this range, the cytoplasm is largely devoid of membranes, but contains primarily ribosomes and mitochondria. In slightly larger oocytes, smooth-surfaced cytomembranes first appear in the perinuclear cytoplasm. At this time, the outer layer of the germinal vesicle nuclear envelope (GVNE) shows frequent connections with long membranous lamellae that extend for considerable, but variable distances into the juxtanuclear ooplasm. The number of smooth membranous lamellae increases tremendously as the oocytes increase in diameter. In such oocytes as well, frequent continuities are observed between the outer membrane of the GVNE and many of the cytoplasmic membranes. Eventually, as the ooplasm becomes populated with extensive numbers of membranous lamellae, instances of continuity between the membranous lamellae and nuclear envelope now become sparse and eventually non-existent. The frequent connections observed between membranous lamellae and the outer membrane of the GVNE during a circumscribed interval of diplotene strongly implicate the GVNE in the generation of extensive amounts of cytoplasmic membrane. The ooplasm of larger oocytes in the size range indicated contain numerous Golgi complexes and large quantities of annulate lamellae most of which are positioned in the peripheral or subcortical ooplasm, as well as extensive quantities of smooth membranes of the endoplasmic reticulum and lipid droplets.     

Morpho-functional considerations on the annulate lamellae of the human oocyte]

Ovarian biopsy specimens from four girls in complete remission state of acute lymphoblastic leukemia, previously treated with antiblastic chemotherapy for about three years, were examined by means of electron microscopy. The normal morphology of residual follicles and, in particular, the observation that annulate lamellae were always present in oocytes of primordial and primary follicles, gave the chance to consider a possible functional role and to suggest a prognosis for future fertility. The similarities in structure to the nuclear envelope and the relation between annulate lamellae and other cellular organelles (especially endoplasmic reticulum and ribosomes) suggest that lamellae may be involved in the release, assembly or activation of stored development information. The annulate lamellae could prove to be an important organelle that participates in the regulation of gene expression. Therefore, the presence of annulate lamellae in oocytes of primordial and primary follicles may present the possibility of a normal development for these cells in which long-lived gene products are synthesized and transported to the cytoplasm for storage and use later in development. The above hypothesis, while leads to consider these patients at risk for low fertility and early menopause, does not consider them as definitely infertile.     

Intranuclear and cytoplasmic annulate lamellae in grasshopper spermatocytes (Genus Melanoplus)

Intranuclear and cytoplasmic annulate lamellae were studied in grasshopper spermatocytes (Melanoplus) with the electron microscope. Although cytoplasmic annulate lamellae were observed in all three species examined, intranuclear annulate lamellae were found in only one species. The intranuclear annulate lamellae encompass certain nuclear material adjacent to the nuclear envelope forming a vesicle that is extruded into the spermatocyte cytoplasm. In this same species, cytoplasmic annulate lamellae are seen contiguous with granular masses of varying size. These structures were noted as being morphologically indistinguishable from the "yolk nuclei" of dragonfly oocytes (Kessel and Beams, 1969; Kessel, 1973).     

Fine structure of the developing oocytes in adultArgas (Persicargas) arboreus (Ixodoidea: Argasidae)

The structure of the developing oocytes in the ovary of unfed and fed femaleArgas (Persicargas) arboreus is described as seen by scanning (SEM) and transmission (TEM) electron microscopy. The unfed female ovary contains small oocytes protruding onto the surface and its epithelium consists of interstitial cells, oogonia and young oocytes. Feeding initiates oocyte growth through the previtellogenic and vitellogenic phases of development. These phases can be observed by SEM in the same ovary.The surface of isolated, growing oocytes is covered by microvilli which closely contact the basal lamina investing the ovarian epithelium and contains a shallow, circular area with cytoplasmic projections and a deep pit, or micropyle, at the epithelium side. In more advanced oocytes the shell is deposited between microvilli and later completely covers the surface.Transmission EM of growing oocytes in the previtellogenic phase reveals nuclear and nucleolar activity in the emission of dense granules passing into the cytoplasm and the formation of surface microvilli. The cell cytoplasm is rich in free ribosomes and polysomes and contains several dictyosomes associated with dense vesicles and mitochondria which undergo morphogenic changes as growth proceeds. Membrane-limited multivesiculate bodies, probably originating from modified mitochondria, dictyosomes and ribosomal aggregates, are also observed. Rough endoplasmic reticulum is in the form of annulate lamellae. During vitellogenesis, proteinaceous yolk bodies are formed by both endogenous and exogenous sources. The former is involved in the formation of multivesicular bodies which become primary yolk bodies, whereas the latter process involves internalization from the haemolymph through micropinocytosis in pits, vesicles and reservoirs. These fuse with the primary yolk bodies forming large yolk spheres. Glycogen and lipid inclusions are found in the cytoplasm between the yolk spheres.     

Exocytosis of glycogen during maturation of amphibian oocytes

The repartition and fate of glycogen β has been followed during progesterone-induced maturation of amphibian oocytes. The use of specific staining, both at the cytological and ultrastructural level, demonstrates that glycogen tends to be extruded from the oocyte during maturation of the urodeles Pleurodeles waltlii and Ambystoma mexicanum. No such effect of the hormone is observed in Xenopus laevis, where only a slight centrifuge migration of the glycogen could be recorded. Stacks of annulate lamellae increase during the early phase of in vitro progesterone-induced maturation (2 to 9 hours after progesterone application). After germinal vesicle breakdown (about 12 hours after beginning the progesterone treatment) annulate lamellae have disappeared and numerous masses of vesicles are present in the cytoplasm of Pleurodeles and Ambystoma matured oocytes. We never observed any close relation between the annulate lamellae and these vesicles.     

Unusual intracytoplasmic lamellar bodies in a malignant gonadal stromal tumor

Characteristic intracytoplasmic lamellar bodies were found in a malignant gonadal stromal tumor. These bodies consisted of the stacks of up to 200 tubular cisternae arranged in parallel. Each cisterna had a circular section in tangential view and a diameter of about 85 nm. The cisternae on the outermost side of these lamellar bodies tended to be dilated and adorned with ribosomes. The ends of cisternae were often contiguous with rough-surfaced endoplasmic reticulum. The latter feature is also seen in annulate lamellae, but periodically spaced annuli or discontinuities characteristic of annulate lamellae were never observed. Furthermore, fine ribosomal granules resembling a rosary were recognizable along the whole circumference of the outer surface of each cisterna. The unique structure we describe is a cytoplasmic organelle which, like annulate lamellae, is closely associated with the endoplasmic reticulum and is presumed to be related to the genesis of rough-surfaced endoplasmic reticulum in tumor cells.     

Intracellular signals trigger ultrastructural events characteristic of meiotic maturation in oocytes of Xenopus laevis

Summary Oocytes of Xenopus laevis were treated with agents which induce individual intracellular signals normally evoked during the process of meiotic maturation. Ultrastructural analysis of these oocytes allowed identification of specific second messengers that individually trigger single ultrastructural changes characteristic of the meiotic maturation process: Manipulation of intracellular cAMP levels induced changes in cortical granule position. Cytoplasmic alkalinization triggered a disruption of the annulate lamellae, a specialized organelle in the periphery of oocytes. Activation of protein kinase C caused rapid formation of a cortical endoplasmic reticulum and subsequent disruption of cortical granules. Manipulation of transmembrane calcium flux had varied results dependent upon the agent employed. Two of the treatments, Verapamil and zero external calcium, induced a reorganization in the oocyte periphery. The results indicate that these ultrastructural events are under the control of specific intracellular signals known to be elicited during meiotic maturation.     

NEGATIVE STAINING AND ADENOSINE TRIPHOSPHATASE ACTIVITY OF ANNULATE LAMELLAE OF NEWT OOCYTES

Semi-isolated annulate lamellae were prepared from single newt oocytes (Triturus alpestris) by a modified Callan-Tomlin technique. Such preparations were examined with the electron microscope, and the negative staining appearance of the annulate lamellae is described. The annulate lamellae can be detected either adhering to the nuclear envelope or being detached from it. Sometimes they are observed to be connected with slender tubular-like structures interpreted as parts of the endoplasmic reticulum. The results obtained from negative staining are combined with those from sections. Especially, the structural data on the annulate lamellae and the nuclear envelope of the very same cell were compared. Evidence is presented that in the oocytes studied the two kinds of porous cisternae, namely annulate lamellae and nuclear envelope, are markedly distinguished in that the annulate lamellae exhibit a much higher pore frequency (generally about twice that found for the corresponding nuclear envelope) and have also a relative pore area occupying as much as 32% to 55% of the cisternal surface (compared with 13% to 22% in the nuclear envelopes). The pore diameter and all other ultrastructural details of the pore complexes, however, are equivalent in both kinds of porous cisternae. Like the annuli of the nuclear pore complexes of various animal and plant cells, the annuli of the annulate lamellae pores reveal also an eightfold symmetry of their subunits in negatively stained as well as in sectioned material. Furthermore, the annulate lamellae are shown to be a site of activity of the Mg-Na-K-stimulated ATPase.     

Relationships between annulate lamellae and filament bundles in oocytes of the zebrafish,Brachydanio rerio

Summary Bundles of filaments have been observed in the vitellogenic oocyte of the zebrafish, Brachydanio rerio; and these filaments illustrate a close spatial and structural relationship to annulate lamellae. The filaments range from 6–8 nm in diameter, and the annulate lamellae may cap both rounded ends of the bundle as well as extend parallel to the surface of the filament bundles. The ends of the filaments can be observed to exhibit an apparent termination in close relation to pore margins of the annulate lamellae, the membrane of the interpore regions of the annulate lamellae, as well as many nearby polyribosomes. The possible functional significance of this unique relationship is discussed in reference to a recent hypothesis regarding the function of annulate lamellae.     

Structural organization and possible functional role of annulate lamellae containing cytoplasmic pores

This review is devoted to annulate lamellae, a specific compartment of endoplasmic reticulum that occurs, presumably, in actively growing and rapidly dividing cells (oocytes, embryonic and tumor cells). We summarized both earlier and recent data on the dustribution of annulate lamellae in various cell types, on their morphology, and the distribution of interaction with intracellular structures at various treatments. As the annulate lamellae contain cytoplasmic pore complexes, a special attention was paid to their relation with nuclear pores. Possible functions of the annulate lamellae in intracellular processes and, particularly, in nuclear envelope assembly, are discussed.     

Annulate lamellae and crystalline inclusions in granular endoplasmic reticulum of the islet organ and associated tissues of a cyclostome,Myxine glutinosa

Cytoplasmic annylate lamellae were found in the islet organ of a cyclostome, the hagfish (Myxine glutinosa), predominantly in cells interpreted as young proliferating beta-cells, and also in endocrine cells and enterocytes of the bile duct and gut and in the endothelial cells of small blood vessels. A close association was observed annulate lamellae and granular endoplasmic reticulum. Both in cells with and in those without annulate lamellae, crystalline inclusions of proteinaceous nature were seen in granular endoplasmic reticulum. These inclusions were occasionally closely associated to annulate lamellae, and a direct continuity could be seen between granular endoplasmic reticulum and the outer nuclear membrane surrounding an inclusion partially situated in the perinuclear cisterna. Rod-shaped structures and rounded electron dense bodies were seen in the nuclei of some islet parenchymal cells. The presence of annulate lamellae in the islet organ and associated tissues of Myxine glutinosa is believed to be related to the very high phylogenetic age of this species. The close association observed between annulate lamellae, granular endoplasmic reticulum, crystalline inclusions, and sometimes also nuclear membranes, may be of functional significance.     

Ultrastructural observations on the oogenesis of Triops cancriformis (Crustacea,Notostraca)

Summary The first stages of the oogenesis of Triops cancriformis have been studied. At the outset the oocyte is smaller than the nurse cells. Meiosis begins with typical synaptonemal complexes. The significance of these complexes and of some other peculiar structures of germ cells, i.e., pore complexes and annuli within the nucleus, and annulate lamellae within the cytoplasm are discussed. The morphofunctional uniformity of some cytoplasmic structures (annulate lamellae, concentrically arranged ER, and yolk globules) in the oocyte as well as its nurse cells is also discussed.