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Willemse MTM. MORPHOLOGICAL AND QUANTITATIVE CHANGES IN THE POPULATION OF CELL ORGANELLES DURING MICROSPOROGENESIS OF PINUS SYLVESTRIS L. I. MORPHOLOGICAL CHANGES FROM ZYGOTENE UNTIL PROMETAPHASE I. ACTA ACUST UNITED AC 2015. [DOI: 10.1111/j.1438-8677.1971.tb00708.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Reichelt R, Holzenburg A, Buhle EL, Jarnik M, Engel A, Aebi U. Correlation between structure and mass distribution of the nuclear pore complex and of distinct pore complex components. J Cell Biol 1990; 110:883-94. [PMID: 2324201 PMCID: PMC2116066 DOI: 10.1083/jcb.110.4.883] [Citation(s) in RCA: 371] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Nuclear pore complexes (NPCs) prepared from Xenopus laevis oocyte nuclear envelopes were studied in "intact" form (i.e., unexposed to detergent) and after detergent treatment by a combination of conventional transmission electron microscopy (CTEM) and quantitative scanning transmission electron microscopy (STEM). In correlation-averaged CTEM pictures of negatively stained intact NPCs and of distinct NPC components (i.e., "rings," "spoke" complexes, and "plug-spoke" complexes), several fine structural features arranged with octagonal symmetry about a central axis could reproducibly be identified. STEM micrographs of unstained/freeze-dried intact NPCs as well as of their components yielded comparable but less distinct features. Mass determination by STEM revealed the following molecular masses: intact NPC with plug, 124 +/- 11 MD; intact NPC without plug, 112 +/- 11 MD; heavy ring, 32 +/- 5 MD; light ring, 21 +/- 4 MD; plug-spoke complex, 66 +/- 8 MD; and spoke complex, 52 +/- 3 MD. Based on these combined CTEM and STEM data, a three-dimensional model of the NPC exhibiting eightfold centrosymmetry about an axis perpendicular to the plane of the nuclear envelope but asymmetric along this axis is proposed. This structural polarity of the NPC across the nuclear envelope is in accord with its well-documented functional polarity facilitating mediated nucleocytoplasmic exchange of molecules and particles.
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Affiliation(s)
- R Reichelt
- M.E. Müller Institute for High Resolution Electron Microscopy, Biocenter, University of Basel, Switzerland
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Lee K, Bao J, Wang J, Zhao W, Liu S, Si J, Wang Y, Zhang W, Jiang J. Ultrastructural study of the morphogenesis of herpes simplex virus type 2 in organ cultured human uterine cervix and the interactions between virus and host cell. ACTA ACUST UNITED AC 1987. [DOI: 10.1002/jemt.1060070205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Peters R. Fluorescence microphotolysis to measure nucleocytoplasmic transport and intracellular mobility. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 864:305-59. [PMID: 3539193 DOI: 10.1016/0304-4157(86)90003-1] [Citation(s) in RCA: 216] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Kessel RG. Annulate lamellae (porous cytomembranes): with particular emphasis on their possible role in differentiation of the female gamete. DEVELOPMENTAL BIOLOGY (NEW YORK, N.Y. : 1985) 1985; 1:179-233. [PMID: 3917201 DOI: 10.1007/978-1-4615-6814-8_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- R G Kessel
- Department of Biology, University of Iowa, Iowa City 52242
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Abstract
Ultrastructural findings from the cellular, early osteoid regions of 10 osteosarcoma lesions are described. The characteristic features included irregularity in nuclear shape, margination of the chromatin, a large number of nucleoli, normal-sized nuclear pores, undifferentiated cells, poorly differentiated osteoblasts with scanty rough endoplasmic reticulum in annular or lamellar conformation, and malignant osteoblasts characterized by large accumulations of dilated rough endoplasmic reticulum (often in the form of huge anastomosing lakes) and by intracellular filaments. Several of the lesions demonstrated prominent giant cells, most of which were similar ultrastructurally to uninuclear tumor cells rather than to mitochondrialaden giant cells or osteoclasts. Variable amounts of primarily collagenous intercellular matrix were present. Cross-banded collagen fibers with diameters from 30-90 nm were seen as were thinner non-cross-banded fibrils 12-18 nm wide.
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Kessel RG. The structure and function of annulate lamellae: porous cytoplasmic and intranuclear membranes. INTERNATIONAL REVIEW OF CYTOLOGY 1983; 82:181-303. [PMID: 6352549 DOI: 10.1016/s0074-7696(08)60826-8] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Bouteille M, Bouvier D, Seve AP. Heterogeneity and territorial organization of the nuclear matrix and related structures. INTERNATIONAL REVIEW OF CYTOLOGY 1983; 83:135-82. [PMID: 6358101 DOI: 10.1016/s0074-7696(08)61687-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Agutter PS, Suckling KE. Effect of colchicine on mammalian liver nuclear envelope and on nucleo-cytoplasmic RNA transport. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 698:223-9. [PMID: 6182913 DOI: 10.1016/0167-4781(82)90151-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The binding of colchicine to nuclear envelopes was studied in order to elucidate the mechanism whereby this compound inhibits nucleocytoplasmic RNA transport. The results suggest that a single class of colchicine-binding site (dissociation constant=approx. 0.7 mM, concentration=approx. 330 nmol colchicine/mg protein) is localised in the nuclear periphery (pore-lamina) and that binding to these sites effects a constriction of the pore-complexes with concomitant inhibition of RNA egress and disordering of the nuclear membrane phospholipid bilayers.
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Harris JR. The biochemistry and ultrastructure of the nuclear envelope. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 515:55-104. [PMID: 346065 DOI: 10.1016/0304-4157(78)90008-4] [Citation(s) in RCA: 86] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Harris N. Nuclear pore distribution and relation to adjacent cytoplasmic organelles in cotyledon cells of developing Vicia faba. PLANTA 1978; 141:121-128. [PMID: 24414765 DOI: 10.1007/bf00387877] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/1977] [Accepted: 03/10/1978] [Indexed: 06/03/2023]
Abstract
Following a zinc iodine-osmium tetroxide fixation, nuclear pore distribution was studied in 0.3-μm sections from cotyledons of developing Vicia faba L. Localised absence of nuclear pores was found to be associated with proximity of organelles to the nucleus. Golgi cisternae and mitochondria are associated with areas of pore absence while cisternal endoplasmic reticulum and tubular endoplasmic reticulum are linked with areas showing reduction in pore density. Pores were seen in the nuclear membrane adjacent to vacuoles. Pattern analysis of pore distribution indicated possible clustering within an overall regularity.
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Affiliation(s)
- N Harris
- Department of Botany, University of Durham, DH13LE, Durham, UK
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Abstract
Nuclear structures similar to those of the nuclear pore complex were found on chromosomes. This finding indicates that part of the pore complex is retained by the chromosomes through mitosis in the absence of the nuclear membrane. The formation of approximately the same number of pore complexes in the presence and absence of protein synthesis during the first 4 h after mitosis proves the reassembly rather than new synthesis of the pore complex. The structure of pore complexes reconstructed in the absence of protein synthesis cannot be distinguished from the structure of those of control cells.
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Abstract
Aliquots of lymphocyte cell suspensions were pretreated according to the following three schedules before freeze fracturing: (a) prefixed with 2% glutaraldehyde before infiltration with 25% glycerol in medium RPMI-1640; (b) frozen in medium RPMI-1640 without additional pretreatment; and (c) frozen after pretreatment with 25% glycerol in medium RPMI-1640. The diameters of the fractured nuclear pore complexes of cells prefixed with glutaraldehyde were normally distributed within the range 70-120 nm (median 90 nm). The nuclear envelopes of 66-75% of cells processed through schedules b and c, which omitted glutaraldehyde fixation, had 70-120 nm diameter pores, while the remainder had pores with diameters in the range 120-175 nm. The large pores were structurally similar to the smaller pores except for their dimensions. These results indicate that glutaraldehyde gives rise to shrinkage of the larger pores to the minimum, smaller, diameter. Apparent orifices of at least 30 nm diameter were sometimes observed at the centres of these large pore complexes. We propose that the variation in pore diameters may indicate opening and closure of this orifice, and that the widely reported "central granule" of the nuclear pore complex corresponds with the orifice in a closed configuration.
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Kirschner RH, Rusli M, Martin TE. Characterization of the nuclear envelope, pore complexes, and dense lamina of mouse liver nuclei by high resolution scanning electron microscopy. J Biophys Biochem Cytol 1977; 72:118-32. [PMID: 556616 PMCID: PMC2110994 DOI: 10.1083/jcb.72.1.118] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
We have used high resolution scanning electron microscopy (SEM) to study the nuclear envelope components of isolated mouse liver nuclei. The surfaces of intact nuclei are covered by closely packed ribosomes which are distinguishable by SEM from nuclear pore complexes. After removal of nuclear membranes with the nonionic detergent Triton X-100, the pore complexes remain attached to an underlying, peripheral nuclear lamina, as described by others. The surface of this dense lamina is composed of particulate granules, 75-150 A in diameter, which are contiguous over the entire periphery. We did not observe the pore-to-pore fibril network suggested by other investigators, but such a structure might be the framework upon which the dense lamina is formed. Morphometric analysis of pores and pore complexes shows their size, structure, and density to be similar to that of other mammalian cells. In addition, several types of pore complex-associated structures, not previously reported by other electron microscope (EM) techniques, are observed by SEM. Our studies suggest that the major role of the dense lamina is associated with the distribution, stability, and perhaps, biogenesis of nuclear pore complexes. Treatment of isolated nuclei with a combination of Triton X-100 and sodium deoxycholate removes membranes, dense lamina, and nuclear pore complexes. The resulting "chromatin nuclei" retain their integrity despite the absence of any limiting peripheral structures.
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Lott JN, Vollmer CM. Changes in the cotyledons of Cucurbita maxima during germination. V. The nuclear envelope. JOURNAL OF ULTRASTRUCTURE RESEARCH 1975; 52:156-66. [PMID: 1152111 DOI: 10.1016/s0022-5320(75)80108-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Severs NJ, Jordan EG. An interpretive freeze-fracture study of plant cell nuclear pore complexes. JOURNAL OF ULTRASTRUCTURE RESEARCH 1975; 52:85-99. [PMID: 1097725 DOI: 10.1016/s0022-5320(75)80024-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Ward RT, Ward E. Evidence for diaphragms in the pores of annulate lamellae and the nuclear membrane. J Morphol 1975; 146:81-95. [PMID: 1080208 DOI: 10.1002/jmor.1051460105] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Interpretation of cross and tangential sections of the annulate lamellae and nuclear membrane of Rana pipiens oocytes provides evidence in these structures for the existence of disphragms spanning the pores. The evidence appears to rule out explanations ascribing such diaphragms to an optical artifact. More detailed description is given of a component of the pore complex only briefly described heretofore and now called the "intracisternal ring." The varied results and interpretations of studies of the pore complex in various cells are discussed.
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Abstract
The permeability of the amphibian oocyte nuclear envelope in situ has been determined for three tritiated dextrans. The envelope is a sieve, restricting molecular movement between the cytoplasm and nucleus. The patent radius of its pores is about 45å.
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Aaronson RP, Blobel G. Isolation of nuclear pore complexes in association with a lamina. Proc Natl Acad Sci U S A 1975; 72:1007-11. [PMID: 1055359 PMCID: PMC432453 DOI: 10.1073/pnas.72.3.1007] [Citation(s) in RCA: 246] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Nuclear pore complexes have been isolated in association with a 150 A thick lamina by detergent and salt fractionation of nuclear envelopes from rat liver. The pore complexes exhibit characteristic morphology and appear to be attached in a highly specific orientation to the lamina, which extends over relatively large areas. The pore complex-lamina fraction is composed of three major and several minor polypeptides with little or no DNA, RNA, or phospholipid. It is suggested that the association of the pore complexes and the lamina reflects the structural arrangement of the nuclear periphery in vivo.
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Harris JR, Price MR, Willison M. A comparative study on rat liver and hepatoma nuclear membranes. JOURNAL OF ULTRASTRUCTURE RESEARCH 1974; 48:17-32. [PMID: 4135100 DOI: 10.1016/s0022-5320(74)80042-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Wischnitzer S. The submicroscopic morphology of the interphase nucleus. INTERNATIONAL REVIEW OF CYTOLOGY 1973; 34:1-48. [PMID: 4121838 DOI: 10.1016/s0074-7696(08)61933-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Roos UP. Light and electron microscopy of rat kangaroo cells in mitosis. I. Formation and breakdown of the mitotic apparatus. Chromosoma 1973; 40:43-82. [PMID: 4344486 DOI: 10.1007/bf00319836] [Citation(s) in RCA: 94] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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KESSEL R. Structure and Function of the Nuclear Envelope and Related Cytomembranes. ACTA ACUST UNITED AC 1973. [DOI: 10.1016/b978-0-12-571806-6.50011-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
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Berezney R, Macaulay LK, Crane FL. The Purification and Biochemical Characterization of Bovine Liver Nuclear Membranes. J Biol Chem 1972. [DOI: 10.1016/s0021-9258(20)81140-5] [Citation(s) in RCA: 88] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Jacob J, Danieli GA. Electron microscope observations on nuclear pore-polysome association. CELL DIFFERENTIATION 1972; 1:119-25. [PMID: 4670878 DOI: 10.1016/0045-6039(72)90034-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Agutter PS. The isolation of the envelopes of rat liver nuclei. BIOCHIMICA ET BIOPHYSICA ACTA 1972; 255:397-401. [PMID: 4334684 DOI: 10.1016/0005-2736(72)90039-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Scheer U. Ultrastructure of the nuclear envelope of amphibian oocytes. IV. Chemical nature of the nuclear pore complex material. ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE (VIENNA, AUSTRIA : 1948) 1972; 127:127-48. [PMID: 5018203 DOI: 10.1007/bf00582762] [Citation(s) in RCA: 47] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Eckert WA, Franke WW, Scheer U. Actinomycin D and the central granules in the nuclear pore complex: thin sectioning versus negative staining. ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE (VIENNA, AUSTRIA : 1948) 1972; 127:230-9. [PMID: 4111739 DOI: 10.1007/bf00306805] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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La Cour LF, Wells B. The nuclear pores of early meiotic prophase nuclei of plants. ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE (VIENNA, AUSTRIA : 1948) 1971; 123:178-94. [PMID: 4332348 DOI: 10.1007/bf02583472] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Rangan SR, Calvert RC, Vitols K. Fibrillar bundles in canine lymphomas: an ultrastructural study. JOURNAL OF ULTRASTRUCTURE RESEARCH 1971; 36:425-36. [PMID: 4328967 DOI: 10.1016/s0022-5320(71)80115-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Summers MD. Electron microscopic observations on granulosis virus entry, uncoating and replication processes during infection of the midgut cells of Trichoplusia ni. JOURNAL OF ULTRASTRUCTURE RESEARCH 1971; 35:606-25. [PMID: 5142394 DOI: 10.1016/s0022-5320(71)80014-x] [Citation(s) in RCA: 125] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Die Ei- und Embryonalentwicklung vonCorydendrium parasiticum mit besonderer Berücksichtigung der Oocyten-Feinstruktur während der Vitellogenese. ACTA ACUST UNITED AC 1971. [PMCID: PMC7149016 DOI: 10.1007/bf01609462] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
1. Die Ei- und Embryonalentwicklung des HydroidenCorydendrium parasiticum (L.) wurde unter besonderer Berücksichtigung der feinstrukturellen Veränderungen der Oocyten während der Vitellogenese untersucht. 2.Corydendrium bildet als Stockform Monopodien mit Endpolypen und subterminaler Knospung. Das Perisarc beziehungsweise Periderm der Kolonie wird durch mit Toluidinblau metachromatisch anfärbbare Tröpfchen des Ektoderms gebildet; sie zeigen eine parakristalline Binnenstruktur und entsprechen den unter dem Lichtmikroskop sichtbaren, stark acidophilen Grana. In die Grundsubstanz der Mittellamelle sind Fibrillen mit periodischer Anordnung von Untereinheiten eingelagert. Perforationen in der Mittellamelle sind ein Ergebnis durchtretender Zellausläufer, die vermutlich eine Funktion beim Nahrungsaustausch besitzen. 3. Die Eizellen entstehen diffus in der Keimzone unterhalb eines Hydranthen. Ektodermale I-Zellen wandern nachweislich durch die Mittellamelle und differenzieren sich im Entoderm zu Keimzellen. Nur in diesem sind Prophase-Stadien der Meiose zu finden. Mit Berechtigung kann jedoch, trotz unterschiedlicher Herkunft der I-Zellen in der Frühentwicklung, von einer ektodermalen Abstammung der Hydroiden-Keimzellen gesprochen werden. 4. Die Eizellen wandern während der Wachstumsphase auf der Mittellamelle zur Gonophoren-Bildungszone. Die Gonophoren sind Hydranthen-Knospen homolog und vermutlich phyletisch umgewandelte Hydranthen. Frühzeitig in eine Knospenausstülpung einwandernde Oocyten legen deren Entwicklung zum Gonophor fest oder werden durch dessen morphologisch noch nicht sichtbares Blastem angelockt. Die Oocyten werden im Gonophor durch dessen Wachstum passiv mitgenommen und von einem allseitig geschlossenen Follikel-Epithel umgeben. Nach der Endphase ihres Wachstums vollziehen sie im Gonophor ihre beiden Reifeteilungen, wobei sie vorher ihr Follikel-Epithel durchbrochen haben. Die Befruchtung erfolgt entweder im Gonophor noch während des Auskriechens oder kurz danach an dessen Spitze im Freien. 5. Die feinstrukturellen Veränderungen während der Vitellogenese werden entsprechend den Entwicklungsstadien der Eizelle beschrieben. Komplexdotter, Lipidtropfen und Glykogen stehen am Ende der Vitellogenese. Zur Bildung des mengenmäßig überwiegenden Reservematerials der befruchtungsfähigen Eizelle, des Komplexdotters, werden zahlreiche Zwischenstufen geformt. Von besonderem Interesse sind dabei die Cytosomen, die auf Grund ihrer engen Beziehung zum granulären endoplasmatischen Retikulum und wegen ihrer parakristallinen Innenstruktur den „microbodies“ der Leber und Niere ähneln. In dem aus vier unterscheidbaren Komponenten bestehenden Komplexdotter sind vergleichbare parakristalline Strukturen nachweisbar, die den histochemisch im Dotter anderer Tierarten schon nachgewiesenen Enzymen entsprechen könnten. Neben einem Versuch, den Ablauf der Vitellogenese zu rekonstruieren, wird auf den Bau der Kernmembran und des Nucleolus näher eingegangen. 6. Die Furchung beginnt schon während des Ausstoßens der Eier aus dem Gonophor, an das sich diese unter Abscheidung einer Embryonalhülle festkleben. Die Furchung ist total und äqual. Die Kreuzstellung der vier ersten Blastomeren ist die Folge ihrer Verschiebbarkeit gegeneinander. Eine Furchungshöhle tritt nicht auf. Die Keimblätterbildung erfolgt als Morula-Delamination. I-Zellen und Cnidoblasten werden im prospektiven Entoderm gebildet und wandern frühzeitig in das durch eine besondere Rindenzone gekennzeichnete Ektoderm. Eine polare Differenzierung tritt erst kurz vor dem Ausschlüpfen der Planula hervor. 7. Die Planulae behalten bis zu ihrer Umwandlung in Primärpolypen ein solides Entoderm, wie es einem Sterrogastrula-Stadium entspricht. Schon nach einem Tag können sie metamorphosieren. Der bis zu 12 Tagen verzögerte Beginn der Metamorphose in Laborversuchen beruht wahrscheinlich auf der Abwesenheit bestimmter Bakterien.
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Evidence for changes in nuclear permeability during different physiological states. Tissue Cell 1971; 3:1-8. [DOI: 10.1016/s0040-8166(71)80027-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/1970] [Indexed: 11/19/2022]
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Speth V, Wunderlich F. The macronuclear envelope of Tetrahymena pyriformis GL in different physiological states. 3. Appearance of freeze-etched nuclear pore complexes. J Cell Biol 1970; 47:772-7. [PMID: 5497552 PMCID: PMC2108153 DOI: 10.1083/jcb.47.3.772] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Franke WW, Falk H. Appearance of nuclear pore complexes after Bernhard's staining procedure. HISTOCHEMIE. HISTOCHEMISTRY. HISTOCHIMIE 1970; 24:266-78. [PMID: 4099673 DOI: 10.1007/bf00304196] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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41
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Ryser U. Die Ultrastruktur der Mitosekerne in den Plasmodien von Physarum polycephalum. Cell Tissue Res 1970. [DOI: 10.1007/bf00343989] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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