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  • 1995-1999
  • 1985-1989  (112)
  • 1985  (112)
  • Ultrastructure  (112)
  • 101
    Electronic Resource
    Electronic Resource
    Ultrastructural studies on plastids of generative and vegetative cells inLiliaceae 3. Plastid distribution during the pollen development inGasteria verrucosa (Mill.) Duval (1985)
    Springer
    Protoplasma 124 (1985), S. 123-129 
    Details
    ISSN: 1615-6102
    Keywords: First pollen mitosis ; Gasteria verrucosa ; Male plastid inheritance ; Pollen development ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This paper describes the development of pollen grains ofGasteria verrucosa from the late microspore to the mature two-cellular pollen grain. Ultrastructural changes and the distribution of plastids as a result of the first pollen mitosis have been investigated using light and electron microscopy. The microspores as well as the generative and the vegetative cell contain mitochondria and other cytoplasmic organelles during all of the observed developmental stages. In contrast, the generative cell and the vegetative cell show a different plastid content. Plastids are randomly distributed within the microspores before pollen mitosis. During the prophase of the first pollen mitosis the plastids become clustered at the proximal pole of the microspore. The dividing nucleus of the microspore is located at the distal pole of the microspore. Therefore, the plastids are not equally distributed into both the generative and the vegetative cell. The possible reasons for the polarization of plastids within the microspore are briefly discussed. The lack of plastids in the generative cell causes a maternal inheritance of plastids inGasteria verrucosa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279731
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  • 102
    Electronic Resource
    Electronic Resource
    Mitosis in the basidiomycete fungusTulasnella araneosa (1985)
    Springer
    Protoplasma 126 (1985), S. 1-18 
    Details
    ISSN: 1615-6102
    Keywords: Mitosis ; Ultrastructure ; Phylogeny ; Basidiomycotina ; Tulasnella araneosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This is a report of a light and electron microscopic study of mitosis in the basidiomycetous fungusTulasnella araneosa. The study employs serial section analyses of nuclei preselected with fluorescence microscopy. It is the first such study of nuclear division in theTulasnellaceae and the first of conjugately dividing nuclei in basidiomycetous hyphal segments lacking clamp connections. Mitosis inT. araneosa is unusual in that the spindle pole body (SPB) develops asymmetrically; the SPB middle piece is large and transversely curved; and the nuclear envelopes of adjacent late anaphase nuclei fuse. Analyses of mitotic characteristics used for phylogenetic purposes indicate that, of the many characters available, only SPB characteristics are presently valuable. Available evidence indicates that the SPB ofT. araneosa is more different from that ofUredinales than it is from representatives of the other four orders ofBasidiomycotina that have been thoroughly studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01287668
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  • 103
    Electronic Resource
    Electronic Resource
    Massive ribonucleoprotein bodies in gametophyte vegetative cells of the mossTimmiella barbuloides (Brid.) Moenk (1985)
    Springer
    Protoplasma 127 (1985), S. 204-211 
    Details
    ISSN: 1615-6102
    Keywords: Biogenesis ; Cytochemistry ; Ribonucleoprotein bodies ; Ribosomes ; Timmiella barbuloides (Musci) ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Vegetative cells of the gametophyte phase of the mossTimmiella barbuloides (Pottiales) are characterized by large cytoplasmic bodies of spherical shape (SBs) whose ribonucleoprotein composition is cytochemically demonstrated. SBs seem to be derived from massive aggregation of cytoplasmic ribosomes, with possible participation by rough endoplasmic reticulum elements. SBs have been found in stereids, parenchymatous cells and young hydroids of the gametophyte stem, and in euricysts of the leaf nerve. The SBs develop early in the course of cell differentiation and, once formed, persist until advanced stages of cell senescence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276264
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  • 104
    Electronic Resource
    Electronic Resource
    The ultrastructure of the plasmodesmata of the salt glands ofTamarix as revealed by transmission and freeze-fracture electron microscopy (1985)
    Springer
    Protoplasma 125 (1985), S. 13-23 
    Details
    ISSN: 1615-6102
    Keywords: Plasmodesmata ; Ultrastructure ; Freeze-fracture ; Salt glands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Numerous plasmodesmata occur in the walls between the secretory cells ofTamarix salt glands. The plasmalemma bounds the plasmodesmata and is continuous from cell to cell. In freeze-fracture, the e-face of the plasmalemma within the plasmodesmata is virtually devoid of intramembranous particles while, in contrast, the p-face is decidedly enriched with particles. The axial components appear to be a tightly curved membrane bilayer, as judged from measurements and their appearance in freeze-fracture, and the e-face of this membrane is also devoid of particles. Observations from both thin sections and freeze-fracture replicas indicate the presence of a circular cluster of six particles around the axial component near the cytoplasmic termini of the plasmodesmata. These particles extend from the p-face of the axial component to the p-face of the plasmalemma. These observations are summarized in a model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01297346
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  • 105
    Electronic Resource
    Electronic Resource
    Structure and histochemistry of the extrafloral nectary ofAcacia terminalis (Salisb.) MacBride (Leguminosae, Mimosoideae) (1985)
    Springer
    Protoplasma 127 (1985), S. 21-30 
    Details
    ISSN: 1615-6102
    Keywords: Acacia terminalis ; Extrafloral nectary ; Histochemistry ; Secretion ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The extrafloral nectary ofAcacia terminalis is of the flat type and is located on the adaxial surface of the petiole of the bipinnate leaf. The secretory area is restricted to the base of the trough and no gaps or pores were detected by staining with vital dyes. Between the vascular bundles beneath the nectary and the surface cuticle there were three cell types. The cells of the flanking zone adjacent to the vascular bundles did not appear to be producing secretion whereas the cells of the glandular and secretory zones were secreting. The cells of the glandular zone were elongated whereas those of the surface secretory zone were spherical. Both had endoplasmic reticulum and Golgi bodies with secretory vesicles which were observed in close association with the plasmalemma. Secretion accumulated in the intercellular spaces of the glandular zone cells and forced the cells of the secretory zone apart. Symplastic contact was maintained in all cell types by plasmodesmata which were often associated with endoplasmic reticulum. Secretion accumulated beneath the cuticle which was distended but remained intact on the surface of the secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01273698
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  • 106
    Electronic Resource
    Electronic Resource
    Ultrastructural ontogeny of leaf cavity trichomes inAzolla implies a functional role in metabolite exchange (1985)
    Springer
    Protoplasma 129 (1985), S. 10-27 
    Details
    ISSN: 1615-6102
    Keywords: Azolla ; Anabaena ; Symbiosis ; Nitrogen fixation ; Trichome ; Transfer cell ; Ontogeny ; Ultrastructure ; Gland ; Metabolite exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Anabaena azollae is associated with two types of multicellular epidermal trichomes inAzolla leaf cavities, the simple and branched hairs. The observation of transfer cell ultrastructure in some hair cells led to speculation that the cavity hairs might participate in metabolite exchange between the symbionts. The developmental ontogeny of cavity trichomes is described here, using transmission electron microscopy, with a goal of improving our understanding of possible functions of these structures in the symbiosis. The observations have established that all cells of simple and branched hairs develop the structural characteristics of transfer cells, but not simultaneously. Rather, there is an acropetal succession of transfer cell ultrastructure beginning in terminal cells, moving to body cells where present, and ending in stalk cells. The transfer cell stage is followed immediately by senescence in all hair cells. The timing of transfer cell differentiation, considered together with information from other studies, suggests that branched hairs may be involved in exchange of fixed nitrogen between the symbionts, while simple hairs may participate in exchange of fixed carbon fromAzolla toAnabaena.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01282301
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  • 107
    Electronic Resource
    Electronic Resource
    The initiation, development and structure of root nodules inElaeagnus angustifolia L. (Elaeagnaceae) (1985)
    Springer
    Protoplasma 128 (1985), S. 107-119 
    Details
    ISSN: 1615-6102
    Keywords: Actinorhizal root nodules ; Development ; N2 fixation ; Elaeagnus ; Frankia ; Symbiosis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A correlated light and electron microscopic study was undertaken of the initiation and development of root nodules of the actinorhizal tree species,Elaeagnus angustifolia L. (Elaeagnaceae). Two pure culturedFrankia strains were used for inoculation of plants in either standing water culture or axenic tube cultures. Unlike the well known root hair infection of other actinorhizal genera such asAlnus orMyrica the mode of infection ofElaeagnus in all cases was by direct intercellular penetration of the epidermis and apoplastic colonization of the root cortex. Root hairs were not involved in this process and were not observed to be deformed or curled in the presence of the actinomyceteFrankia. In response to the invasion of the root, host cells secreted a darkly staining material into the intercellular spaces. The colonizingFrankia grew through this material probably by enzymatic digestion as suggested by clear dissolution zones around the hyphal strands. A nodule primordium was initiated from the root pericycle, well in advance of the colonizingFrankia. No random division of root cortical cells, indicative of prenodule formation was observed inElaeagnus. As the nodule primordium grew in size it was surrounded by tanninised cells of a protoperiderm. The endophyte easily traversed this protoperiderm, and once inside the nodule primordium cortex ramified within the intercellular spaces at multiple cell junctions. Invasion of the nodule cortical cells occurred when a hyphal branch of the endophyte was initiated and grew through the plant cell wall, again by apparent enzymatic digestion. The plant cell plasmalemma of invaded cells always remained intact and numerous secretory vesicles fused with it to encapsulate the advancingFrankia within a fibrous cell wall-like material. Once within the host cell some endophyte cells began to differentiate into characteristic vesicles which are the presumed site of nitrogen fixation. This study clearly demonstrates that alternative developmental pathways exist for the development of actinorhizal nitrogen-fixing root symbioses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276333
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  • 108
    Electronic Resource
    Electronic Resource
    Formation of the plasma membrane during regeneration ofParamecium caudatum (1985)
    Springer
    Protoplasma 125 (1985), S. 94-102 
    Details
    ISSN: 1615-6102
    Keywords: Biogenesis ; Plasma membrane ; Regeneration ; Ultrastructure ; Paramecium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Fragments ofParamecium caudatum cells obtained by merotomy were fixed in 1% OsO4 within 5 seconds after cutting. The ultrastructure of the damaged area of the fragment was studied in oriented ultrathin sections and by scanning electron microscopy. The cytoplasm exposed by merotomy was covered during a few seconds with a new membrane. This was a typical trilaminar membrane continuous with the plasma membrane covering the undamaged surface of the cell. The surface over the wound was wrinkled into irregular grooves and ridges. The cytoplasm, mitochondria and trichocysts in the injured region were electron translucent. The cytoplasm under the new membrane contained an unusually high amount of small membrane vesicles, 20–90 nm in diameter. These were probably the remnants of subpellicular alveoli and the plasma membrane destroyed by microsectioning. The possibility that the exposed cytoplasm would be covered by mere shifting of the existing plasma membrane can be excluded. The complex structure of the cortex with its subpellicular alveoli and regularly distributed cilia provide a strong argument against this notion. It seems probable that the new membrane was built up from the available molecular material,e.g., phospholipids and proteins present in the cytoplasm. Fragments of the membrane and alveolar membranes in the form of small vesicles may have also been included into the new membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01297354
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  • 109
    Electronic Resource
    Electronic Resource
    The ultrastructure of mitosis inIsochrysis galbana parke (Prymnesiophyceae) (1985)
    Springer
    Protoplasma 125 (1985), S. 140-151 
    Details
    ISSN: 1615-6102
    Keywords: Mitosis ; Cytokinesis ; Alga ; Isochrysis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitosis and cytokinesis have been studied in the flagellate algaIsochrysis galbana Parke (Prymnesiophyceae). Nuclear division is preceded by replication of the flagella and haptonema, the Golgi body and the chloroplast; fission in the chloroplast occurs in the region of the pyrenoid. During prophase, spindle microtubules radiating from two ill-defined poles are formed. The nuclear envelope breaks down and the chromatin condenses. At metaphase the spindle is fully developed, some pole-to-pole microtubules passing through the well-defined chromatin plate, others terminating at it. No kinetochores or individual chromosomes were observed. By late metaphase, many Golgi-derived vesicles may be seen against the two poleward faces of the metaphase plate. During anaphase, the two daughter masses of chromatin move towards the poles. In early telophase, the nuclear envelope of each daughter nucleus is complete only on the side towards the adjacent chloroplast, remaining open on the interzonal side. However, during telophase each nucleus becomes reorientated so that it lies lateral to the long axis of the spindle and with its open side towards the chloroplasts. By late telophase, each new nuclear envelope is complete and confluence with the adjacent chloroplast ER established. Cytokinesis and subsequent segregation of the daughter cells are effected by the dilation of Golgi- and ER-derived vesicles in the interzonal region. No microtubular structures are involved. Comparisons with the results from other studies of mitosis in members of thePrymnesiophyceae show that they all have a number of features in common, but that there are differences in detail between species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01297359
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  • 110
    Electronic Resource
    Electronic Resource
    293. Die Struktur des normalen und entziindlich veränderten Peritoneums des Menschen — eine elektronenmikroskopische Studie (1985)
    Springer
    Langenbeck's archives of surgery 366 (1985), S. 703-703 
    Details
    ISSN: 1435-2451
    Keywords: Ultrastructure ; Peritoneum ; Bacterial peritonitis ; Ultrastruktur ; Peritoneum ; Bakterielle Peritonitis ; Rasterelektronenmikroskopie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Studienergebnisse über eine dreijährige rasterelektronenmikroskopische and transmissionselektronenmikroskopische Untersuchung des Peritoneums ergaben, daß bei Patienten mit bakterieller Peritonitis die Mesothelzellen abgerundet sind, keine langen Mikrovilli im Peritoneum parietale ausgebildet werden, jedoch auf der Oberfläche Fibrinablagerungen, Epithelaufbrüche und Kollagenfasern feststellbar sind. Die Abwehrmechanismen bei Peritonitis beginnen mit Kontraktion der Mesothelzellen and Bildung von Intercellularspalten Bowie Stomata. Bei fortgeschrittener Peritonitis kommt es zur Destruktion des Mesothels mit Epithelaufbrüchen and Mobilisation von Epithelzellen zum Zwecke der Phagocytose.
    Notes: Summary The human peritoneum was studied by transmission and scanning electron microscopy, which demonstrated oval-shaped mesothelial cells, disappearance of the long microvilli at the parietal peritoneum, fibrinous membranes, collagenous fibrillae, and epithelial cracks in cases of bacterial peritonitis. The defense mechanism begins with mesothelial cell contractions and then formation of intercellular gaps and stomata. In advanced peritonitis, the mesothelial cells disintegrate with cracks and are finally mobilized for phagocytosis. After continuous peritoneal lavage, the cellular structures of the human peritoneum appear almost normal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01836891
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  • 111
    Electronic Resource
    Electronic Resource
    Electron microscopy of semithick sections: Advantages for biomedical research (1985)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 11-28 
    Details
    ISSN: 0741-0581
    Keywords: Ultrastructure ; Semithick sections ; Three-dimensional ; Serial sections ; Stereomicroscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Many transmission electron microscopes are available which can be used to examine biological material in 0.25-0.50-μm-thick sections. When compared to the traditional thin section, these “semithick” sections possess a number of inherent advantages: They can be screened for content with the phase contrast light microscope, they facilitate many types of studies requiring an analysis of serial sections, and they are frequently the optimum thickness for stereomicroscopy. Structures such as microtubule-associated components, as well as structural relationships between cellular constituents, may also be clearly visible in semithick sections which are not visible, or go unnoticed, in thin sections. Together these advantages enable an investigator to obtain a more complete three-dimensional picture of a cell or cell component in a significantly (i.e., up to 90%) shorter period of time than would be required if thin sections were used. Semithick sections may, therefore, make a study feasible which is not approachable, or which is approachable only with great difficulty, by conventional thin sectioning techniques.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1060020103
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  • 112
    Electronic Resource
    Electronic Resource
    Current basis for the ultrastructural clinical diagnosis of tumors: A review (1985)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 305-351 
    Details
    ISSN: 0741-0581
    Keywords: Tumor ; Diagnosis ; Electron microscopy ; Ultrastructure ; Pathology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The ultrastructural diagnosis of tumors requires a careful analysis that should be done in an orderly fashion. It requires precise planning from the time of specimen collection to the selection of the area to be examined. Pictures must be taken systematically and every micrograph should allow to answer whether the number of cells photographed is adequate; whether mitoses are present, what is the pattern of the tumor; what is the appearance of the cell membrane; whether the cells are joined by junctional complexes; whether free surfaces possess microvilli or cilia; what organelles are present and how they are distributed; whether there are secretory granules, melanosomes, or other cytoplasmic elements. Nuclear and nucleolar size and shape have to be taken into consideration. The composition of the interstitial extracellular matrix is important in certain types of tumors. Although these questions are not the only ones to be addressed, their use in a logical fashion is helpful when it concerns the ultrastructural diagnosis.
    Additional Material: 70 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1060020404
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