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  • Ultrastructure  (125)
  • Springer  (125)
  • American Institute of Physics
  • Blackwell Publishing Ltd
  • Cell Press
  • Oxford University Press
  • 2010-2014
  • 2005-2009
  • 1985-1989  (31)
  • 1975-1979  (94)
  • 1945-1949
  • 2013
  • 2009
  • 2007
  • 2005
  • 1987  (31)
  • 1978  (94)
Collection
Keywords
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Years
  • 2010-2014
  • 2005-2009
  • 1985-1989  (31)
  • 1975-1979  (94)
  • 1945-1949
Year
  • 1
    Electronic Resource
    Electronic Resource
    Coquille de l'oeuf de caille: Étude ultrastructurale et cristallographique (1978)
    Springer
    Calcified tissue international 25 (1978), S. 145-159 
    Details
    ISSN: 1432-0827
    Keywords: Bird egg shell ; Ultrastructure ; Calcification ; Electron diffraction ; Microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The egg-shell of Japanese quail was studied by several techniques. Semithin sections (1μm thick) of non-decalcified shell were observed by normal and polarized light microscopy. Thin sections of non-decalcified shell, examined by transmission electron microscopy, permitted us to observe the forms and dimensions of crystals of calcite within different layers of the shell: mammilary layer, layer of cones, palissade layer and surface crystal layer. There appears to be two distinct zones in the layer of cones as well as in the superficial crystal layer. Electron microdiffraction revealed the orientation of calcite crystals in the columns. Some crystal defects (twins?) were described and the possibility of their artefactual formation during ultramicrotomy is discussed. Localization of Ca, Mg, P and S were made by X-ray microanalysis of semithin sections. This technique shows that shell membranes, and chiefly the true cuticle, are also mineralized but, in these layers, minerals are not crystallized. Otherwise the distribution of Mg is not uniform throughout the shell thickness; it is less concentrated in the external zone of the layer of cones. These results together with observation of developing shells by scanning electron microscopy allowed us to propose a scheme for shell organization of the quail egg. This organization was related with decalcification which occurs during hatching.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010763
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructure of cells in the cambial region during winter hardening and spring dehardening in Salix dasyclados Wim. grown at two nutrient levels (1987)
    Springer
    Trees 1 (1987), S. 151-163 
    Details
    ISSN: 1432-2285
    Keywords: Cambial activity ; Frost hardiness ; Phenology ; Salix ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The ultrastructure of cells in the cambial region of Salix dasyclados Wim. (clone 78056) was studied during the development of winter hardiness and the onset of cambial activity in spring. Plants were grown at relative growth rates (RG) of 8% and 12% respectively, resulting in different nitrogen content in the stems. Frost hardiness of the plants was estimated by standardized freezing tests. Plants with a higher nitrogen status ceased growth later and started re-growth earlier in spring than plants with lower nitrogen content. Differences in ability to withstand low temperatures during autumn and spring were found between plants grown in the two nutrient treatments. During the development of frost hardiness in the autumn, the number of meristematic cells in the cambial region decreased. The cessation of meristematic activity was accompanied by cell wall thickening and ultrastructural changes in the cells. Frost hardiness increased from the ability to survive -6° C in October to survival of -80° C at the beginning of December. From November to February the cambial region comprised a layer of 2–3 thick-walled cells with conspicuous ultrastructural features. Starch accumulated in plastids in September, decreased during November to March and then increased again in accordance with changes of frost hardiness. Onset of cambial activity began between the end of March and the beginning of April, as shown by increased vacuolization of meristematic cells and mitotic activity. By April, the starch content had increased and lipolysis was observed. Frost hardiness had decreased, and plants with low and high nitrogen content were able to survive -15° C and -10° C, respectively. After budburst, all axillary shoot parts were damaged at temperatures below-3° C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00193558
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  • 3
    Electronic Resource
    Electronic Resource
    Étude en microscopie électronique et par cytophotométrie à balayage de la structure et de la distribution de la chromatine dans les noyaux des cellules cartilagineuses deTriturus cristatus âgés au cours de la régénération (1978)
    Springer
    Development genes and evolution 184 (1978), S. 195-211 
    Details
    ISSN: 1432-041X
    Keywords: Ultrastructure ; Scanning cytophotometry ; Chromatin ; Chondrocytes ; Regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les cellules cartilagineuses des membres postérieurs deTriturus cristatus en régénération après amputation, ont été étudiées en microscopie électronique et par cytophotométrie à balayage. Nous nous sommes intéressés à la structure et à la distribution de la chromatine mais aussi à différents organites cytoplasmiques. Dans l'étude de cytophotométrie à balayage, la chromatine a été considérée à travers son constituant majeur, l'ADN, coloré par la réaction de Feulgen. Au cours de la régénération du membre, l'hétérochromatine initialement condensée, essentiellement accolée à la membrane nucléaire se décondense. Les vacuoles du cytoplasme, caractéristiques des animaux âgés par rapport aux animaux jeunes, disparaissent, les mitochondries et le reticulum endoplasmique rugueux deviennent plus abondants. Les caractéristiques nucléaires de l'activation cellulaire apparaissent précocement, précédent les modifications cytoplasmiques et conduisent à des cellules en tous points identiques aux cellules d'animaux jeunes en dehors de tout processus régénératif. Cette phase d'euchromatisation et de restructuration cytoplasmique est peut-être nécessaire à l'accroissement d'activité métabolique et à la division cellulaire qui suivent. Son déroulement peut expliquer tout au moins le ralentissement de la régénération observé chez les animaux âgés par rapport aux animaux jeunes.
    Notes: Summary Cartilaginous cells of aged newts (Triturus cristatus) were studied during hind limb regeneration. The electron microscope was used to study the structure and distribution of chromatin in the cell nuclei, while the DNA content of the chromatin was measured by means of a scanning cytophotometer. Changes in the ultrastructure of the cytoplasm during regeneration were also studied. It was observed that the structure and distribution of chromatin in the activated cell is greatly modified. In the non-activated cell of the aged newt, the chromatin is found highly condensed and distributed peripherally close to the nuclear membrane. In contrast, in the activated cells, the chromatin is much less condensed and is distributed throughout the nucleus. Moreover, cytoplasmic vacuoles, found only in the non-activated aged cells, disappear and an increase in the mitochondria and rough endoplasmic reticulum is also observed. Changes in the nuclear structure are observed prior to the cytoplasmic modifications. It is interesting to note that the process of activation induces structural changes in the aged cells which make these cells appear to be structurally identical to the young cells. This process of rejuvenation takes 3–5 days in the newt. We suggest that these structural changes of the chromatin and cytoplasm in the aged cells are necessary to increase the metabolic activity which precedes cell division. It may also explain why regeneration takes a longer time in the aged animals than in the young ones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848254
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  • 4
    Electronic Resource
    Electronic Resource
    Retention of the differentiated state by larvalXenopus liver cells in primary culture (1978)
    Springer
    Development genes and evolution 185 (1978), S. 235-248 
    Details
    ISSN: 1432-041X
    Keywords: Liver ; Primary culture ; Ultrastructure ; Albumin synthesis ; Xenopus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Electron microscopic analysis of primary cultures derived from larvalXenopus liver has shown that these cells, although they form only two-dimensional aggregates, retain and presumably also develop structural characteristics typical of liver parenchyma cells, such as bile canaliculi with microvilli and epithelial junctional complexes. As judged from structural criteria, primary cultures contain 80–90% hepatocytes. In contrast to the intact tissue, primary cultures showed excessive development of microfilaments, however. Incorporation of labeled amino acids has revealed further that the capacity for protein synthesis is maintained in culture and that synthesis of liverspecific protein albumin is maintained in vitro, even in liver cultures derived from thyrostatic tadpoles. This latter result suggests that initiation of albumin synthesis in the larval liver is probably not dependent upon thyroid hormones but rather reflects the protodifferentiated state of this tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848354
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  • 5
    Electronic Resource
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    Membranes during yolk-platelet development in oocytes of the toad Bufo marinus (1987)
    Springer
    Development genes and evolution 196 (1987), S. 367-371 
    Details
    ISSN: 1432-041X
    Keywords: Vitellogenesis ; Bufo marinus oocyte ; Yolk-platelet membrane ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Oocytes of the toad Bufo marinus have been studied by means of thin section and particularly freeze-fracture electron microscopy to characterize the cytoplasmic membranes around the yolk organelle, and the storage of yolk material in precursors and platelets. This appears to be a previously unknown type of yolk-platelet formation. During yolk-organelle development from the primordial precursor to the bi-partite fully grown yolk platelet, numerous lipoid droplets are attached to the periphery of the platelet, indicating an intense uptake of lipids. As is typical for amphibians, the fully grown yolk platelet has a crystalline internum covered by a dense osmiophilic externum, and the whole organelle is enveloped by a plasma membrane that shows no direct connection or fusion with endocytotic vesicles. The yolk membrane exhibits few intramembraneous particles (IMPs) at the core areas and some more where it borders fields of lipoid droplets. Here the IMPs show a net-like arrangement in the furrows between adjacent droplets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00375773
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  • 6
    Electronic Resource
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    Ultrastructure, histology, and innervation of the mantle edge of the freshwater pulmonate snailsLymnaea stagnalis andBiomphalaria pfeifferi (1978)
    Springer
    Calcified tissue international 26 (1978), S. 271-282 
    Details
    ISSN: 1432-0827
    Keywords: Shell formation ; Free nerve endings ; Ultrastructure ; Lymnaea stagnalis ; Biomphalaria pfeifferi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The mantle edge of the freshwater pulmonate snailsLymnaea stagnalis andBiomphalaria pfeifferi was investigated with histochemical and ultrastructural methods. The mantle edge gland, which is involved in shell formation, consists of the periostracal groove and the belt. This belt appears to be composed of various regions. In the area of the periostracal groove a number of subepithelial gland cell types occur; these release their products into the groove. Between the groove cells ciliated free nerve endings terminate; the corresponding perikarya occur in the subepidermal connective tissue. Also in the posterior belt region free nerve endings were observed between the epithelial cells; in addition, a particular type of subepithelial gland cell was found in this area. The epithelial cells of this part of the belt have the ultrastructural characteristics of ion and water transporting cells; they are probably involved in calcium deposition and resorption. The possible role of the free nerve endings and of the subepithelial gland cells is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013270
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  • 7
    Electronic Resource
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    Disappearence of the intracytoplasmic membranes inRhodopseudomonas sphaeroides (1978)
    Springer
    Archives of microbiology 117 (1978), S. 293-295 
    Details
    ISSN: 1432-072X
    Keywords: Rhodopseudomonas sphaeroides ; Intracytoplasmic membranes ; Membranes ; Ultrastructure ; Bacteriochlorophyll ; Chromatophores
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The photosynthetic bacterium,Rhodopseudomonas sphaeroides, can be grown phototrophically (light, anaerobiosis), of chemotrophically (dark, aerobiosis). In the first case, it contains intracytoplasmic membranes with photosynthetic pigments. When shifted from phototrophy to chemotrophy these membranes disappear in an unknown fashion. In the present experiment, samples were taken for electron microscopy, cell density and bacteriochlorophyll determinations after shift from phototrophy to chemotrophy. The density of intracytoplasmic vesicles was measured on micrographs. During the first 2h growth is very slow and the ultrastructure remains unaltered. As growth resumes, the vesicles disappear at a rate which implies that they are not incorportated into the cytoplasmic membrane, nor actively digested, but remain intact and become increasingly diluted in the cytoplasm as the culture grows. The size of the vesicles was estimated to about 500 Å. The number of vesicles in phototrophically grown cells was calculated to about 575 per cell, and after 6h chemotrophic growth to about 100. The areas of the cytoplasmic and intracytoplasmic membranes are roughly calculated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00738549
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  • 8
    Electronic Resource
    Electronic Resource
    Sporogenesis in Streptomyces melanochromogenes (1978)
    Springer
    Archives of microbiology 118 (1978), S. 309-316 
    Details
    ISSN: 1432-072X
    Keywords: Streptomyces melanochromogenes ; Sporogenesis ; Formation of sporulation septum ; Delimitation, separation, and release of spores ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mode of spore differentiation in a strain of Streptomyces melanochromogenes was followed by analysis of ultrathin sections of sporulating aerial hyphae at various stages of sporogenesis. A special accent was laid on the formation of the sporulation septum and its alterations in the course of spore delimitation and separation. Distinct differences in formation and substructure have been observed between the cross walls of vegetative hyphae and the sporulation septa. Cross walls of vegetative hyphae are formed in a way typical for Gram-positive bacteria by a centripetal annular ingrowth of cytoplasmic membrane, on which wall material immediately is deposited. The development of the sporulation septa is characterized by the accumulation of amorphous material in addition to the newly synthesized wall layer inside the invaginating cytoplasmic membrane. This amorphous septal material will later be decomposed presumably by two lytic systems which cause the separation of the spores. The central region of the finished sporulation septum is perforated by microplasmodesmata. Spores are released by a break down of the surface sheath. The complete spores are enveloped by a twolayered cell wall and the spiny surface sheath.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429123
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  • 9
    Electronic Resource
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    Ultrastructural study of microcyclic macroconidiation in Neurospora crassa (1978)
    Springer
    Archives of microbiology 116 (1978), S. 279-288 
    Details
    ISSN: 1432-072X
    Keywords: Neurospora crassa ; Macroconidia ; Microcycle ; Heat ; Ultrastructure ; Nucleolus ; Proconidia ; Septa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Heat-shock of macroconidia of Neurospora crassa at 46°C followed by shift-down to 25°C determines premature conidiogenesis. The nuclei and cytoplasm of heat-treated, swollen conidia contain spots of a dense material especially concentrated around the nucleolus in short time treated ones. In the first proconidium apically budding on the enlarged tip of the premature conidiophore, small vesicles are peripherally spread. A few such vesicles are later seen lining the initially simple septum separating the proconidial units into conidia. The doubling of this interconidial septum is surface viewn as a thick annulus. Disarticulation of the conidial units intervenes along a septal furrow of electroluscent material. Interconidial continuity through the septal pores is transiently insured by a connective which is ruptured for final liberation of the conidia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00417852
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  • 10
    Electronic Resource
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    Vesicle formation and cellulose degradation in Bacteroides succinogenes cultures: ultrastructural aspects (1987)
    Springer
    Archives of microbiology 148 (1987), S. 150-154 
    Details
    ISSN: 1432-072X
    Keywords: Bacteroides ; Vesicles ; Ultrastructure ; Cellulolytic bacteria ; Rumen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In 3-day-old cultures of Bacteroides succinogenes grown on filter paper, no cell division was observed. When grown on cellulosic substrate, bacteria exhibited vesicles clustered within cell wall pockets. In 2 day-old filter paper cultures, cells adhered tightly to the substrate. Twenty to 30% of them were dividing. There were cell wall pockets in about 25% of the bacteria, but no vesicles. Whether they adhered to the cellulosic substrate or not, and irrespective of the age of the bacteria, storage polysaccharides were found in the form of dense granules in the cytoplasm. It would appear that vesicles are not essential for cellulose degradation, but are rather a sign of ageing of the cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00425364
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  • 11
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    Morphology and ultrastructure of 11 barley shrunken endosperm mutants (1987)
    Springer
    Theoretical and applied genetics 74 (1987), S. 177-187 
    Details
    ISSN: 1432-2242
    Keywords: Barley ; Grain development ; Mutants ; Ultrastructure ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eleven Na-azide induced barley shrunken endosperm mutants expressing xenia (sex) were characterized genetically and histologically. All mutants have reduced kernel size with kernel weights ranging from 11 to 57% of the wild type. With one exception, the mutant phenotypes are ascribable to single recessive mutant alleles, giving rise to a ratio of 3∶1 of normal and shrunken kernels on heterozygous plants. One mutant (B10), also monofactorially inherited, shows a gene dosage dependent pattern of expression in the endosperm. Among the 8 mutants tested for allelism, no allelic mutant genes were discovered. By means of translocation mapping, the mutant gene of B10 was localized to the short arm of chromosome 7, and that of B9 to the short arm of chromosome 1. Based on microscopy studies, the mutant kernel phenotypes fall into three classes, viz. mutants with both endosperm and embryo affected and with a non-viable embryo, mutants with both endosperm and embryo affected and with a viable embryo giving rise to plants with a clearly mutant phenotype, and finally mutants with only the endosperm affected and with a normal embryo giving rise to plants with normal phenotype. The mutant collection covers mutations in genes participating in all of the developmental phases of the endosperm, i.e. the passage from syncytial to the cellular endosperm, total lack of aleurone cell formation and disturbance in the pattern of aleurone cell formation. In the starchy endosperm, varying degrees of cell differentiation occur, ranging from slight deviations from wild type to complete loss of starchy endosperm traits. In the embryo, blocks in the major developmental phases are represented in the mutant collection, including arrest at the proembryo stage, continued cell divisions but no differentiation, and embryos deviating only slightly from the wild type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00289966
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  • 12
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    A freeze-fracture study of tight junctions in the pars convoluta and pars recta of the renal proximal tubule (1978)
    Springer
    Cell & tissue research 186 (1978), S. 121-133 
    Details
    ISSN: 1432-0878
    Keywords: Proximal tubule ; Tight junctions ; Ultrastructure ; Electron microscopy ; Freeze fracturing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of tight junctions of the renal proximal tubule was studied comparing the pars convoluta and pars recta of rat, golden hamster, rabbit, cat, dog and tupaia. Though some interspecies variations were observed, the convoluted portions of the proximal tubules revealed quite uniformly very leaky tight junctions with mainly 1–2 strands. Along the whole proximal tubule of the rabbit kidney including the pars recta only minor differences of the zonulae occludentes were found. By contrast, the tight junctions of the pars recta in other species were much more elaborate, especially in cat and tupaia, having up to 6 strands and an overall depth of more than 150 nm. The implications of these findings are discussed with special regard to the functional differences between the pars convoluta and pars recta of the proximal tubule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219659
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  • 13
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    Exocrine pancreas under experimental conditions (1978)
    Springer
    Cell & tissue research 186 (1978), S. 227-240 
    Details
    ISSN: 1432-0878
    Keywords: Pancreas (rat) ; Pancreatic duct ligation ; Cell membrane ; Intercellular junctions ; Ultrastructure ; Freeze fracture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Exocrine pancreatic tissue was investigated during various intervals after pancreatic duct ligation. Concomitant to the increase of the intraluminal pressure, alterations are found in the arrangement of the luminal membrane surface and the zonulae occludentes of the acinar cells. The zonulae occludentes exhibit a disarrangement of their strands. The number of strands diminishes and small interruptions as well as large discontinuities of the strands are observed in most regions of the acinar cells. Furthermore, gap junctions are found very infrequently between acinar cells. The ultrastructural alterations of the zonulae occludentes suggest a gradual adaptation to the increasing unilateral pressure. However, a leakage of the paracellular permeability barrier occurs which contributes to the known shunt between the compartments of the pancreatic juice and the interstitial space following pancreatic duct obstruction. The present investigation is a further example of alterations in the paracellular permeability and intercellular communication of epithelial cells under pathological conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225533
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  • 14
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    Fine structure of the eyes of orb-weavers, Argiope amoena L. Koch (Aranea: Argiopidae) (1978)
    Springer
    Cell & tissue research 186 (1978), S. 435-452 
    Details
    ISSN: 1432-0878
    Keywords: Photoreceptors ; Arthropod ; Spider (Argiope amoena) ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The anterolateral eye, the posterolateral eye and the posteromedial eye of the web-building spider, Argiope amoena have been examined by light and electron microscopy. The dioptric apparatus of all three eyes is similar in structure, and consists of a cornea, a lens and a vitreous body. The retina contains monopolar receptor cells, the cell bodies of which are present beneath the vitreous body in all three eyes. Proximal processes of the receptor cells form rhabdoms beneath the cell body layer and then extend toward the first optic glomerulus as an ocellar nerve. Two distinct patterns of retinal organization are present in the three eyes. In one type the rhabdomic layer of the retina is backed by a pigmented layer. In the other type the rhabdomic layer is backed by a tapetal reflecting layer. Rhabdomic structure and cytoplasmic inclusions of the receptor cells differ greatly between the two types. The anterolateral eye possesses a single type of retina with the rhabdoms backed by the tapetum. Both the posterolateral and the posteromedial eye are similar in structure, each possessing beneath the common dioptric apparatus retinae of both types.
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    URL: http://dx.doi.org/10.1007/BF00224933
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  • 15
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    Ultrastructure of the subfornical organ of the Japanese quail, Coturnix coturnix (1978)
    Springer
    Cell & tissue research 188 (1978), S. 19-33 
    Details
    ISSN: 1432-0878
    Keywords: Subfornical organ ; Circumventricular organ ; Coturnix quail ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the subfornical organ (SFO) of the Japanese quail has been studied by light and electron microscopy. The SFO is a small semiglobular bulge in the midline on the rostrodorsal wall of the third ventricle between the anterior commissure and tela choroidea. The organ consists of three main parts, anterior stalk, the corpus and the posterior stalk. The anterior stalk is covered by ependymal cells with a few cilia, but the corpus and posterior stalk are characterized by a distinctive lack of cilia and by flat or bulging cell surfaces, which have the appearance of cobble stones. The large bulbous protrusions in the ependymal surface of the posterior stalk suggest a secretory function into the ventricle. In the subependymal layer, there are a few parvocellular neurons that contain small mitochondria, moderately developed Golgi apparatus, lysosomes, dilated cisternae of rER and a few dense-cored granules of 100–120 nm in diameter. They appear to be secretory in nature. Two types of glial cells occur in the subependymal and internal layers. One is small and spindle-shaped with a dense nucleus and elongated cytoplasmic processes; it may be microglial. The other is a small polygonal cell with rounded nucleus and clear cytoplasm containing bundles of filaments; it may be a protoplasmic astrocyte. The neuropil contains three types of axons. The first contains dense-cored granules, 80 nm in diameter, and clear vesicles, 40–60 nm in diameter and is involved in axosomatic synapses. The second type contains dense granules, 120 nm in diameter, and clear vesicles, 40–80 nm in diameter, and shows axodendritic synapses. The third contains peptidergic granules about 100–120 nm in diameter and seems to belong to the organ-specific nerve cells. These axons terminate at the perivascular space of the blood capillaries, suggesting secretion into the blood.
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    URL: http://dx.doi.org/10.1007/BF00220512
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  • 16
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    Origin of the glial processes responsible for the spontaneous postnatal phagocytosis of boutons on cat spinal motoneurons (1978)
    Springer
    Cell & tissue research 189 (1978), S. 203-217 
    Details
    ISSN: 1432-0878
    Keywords: Astrocytes ; Development ; Phagocytosis ; Neuroplasticity ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Previous studies have demonstrated that astrocyte processes are responsible for a spontaneously occurring phagocytosis of boutons on cat spinal motoneurons during the second postnatal week. In the present investigation, the astrocytes and the astrocyte processes in contact with the motoneurons were studied qualitatively and quantitatively during the early postnatal period. It could be concluded that the cells responsible for the phagocytosis of boutons are immature astrocytes. These cells were present not only during the period of phagocytosis but also prior to this period. The type of process responsible for the phagocytosis was present not only during the period of phagocytosis but also prior to and after that period although the relative contribution of such processes to the glia-covered membrane area of the motoneurons was reduced in the older animals. On the basis of these results, the possible specificity of the immature astrocyte as the element responsible for the phagocytosis of boutons during normal development is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209270
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  • 17
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    Synaptic junctions in the sinus gland of the freshwater prawn Palaemon paucidens (1978)
    Springer
    Cell & tissue research 189 (1978), S. 435-440 
    Details
    ISSN: 1432-0878
    Keywords: Neurosecretion ; Sinus gland ; Synapses ; Palaemon ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two types of neurosecretory fibers, designated as Type 5 and Type 6 axons, in the sinus gland of the freshwater prawn, Palaemon, establish contact with other neurosecretory axons by means of synaptic junctions. This finding strongly supports the view that release of some neurohormones from the eyestalk may be regulated by neurosecretory neurons through synaptic transmission.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209131
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  • 18
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    Structure of occluding junctions in ileal epithelial cells of suckling rats (1978)
    Springer
    Cell & tissue research 191 (1978), S. 449-462 
    Details
    ISSN: 1432-0878
    Keywords: Ileum (Rat) ; Occluding junctions ; Freeze-fracture ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two kinds of occluding junctions are found between ileal epithelial cells of suckling rats: apical zonulae occludentes (ZO) and fasciae occludentes (FO) which are associated with the lateral plasma membranes of many epithelial cells. In unfixed preparations, glycerol treatment induces the further proliferation of extensive fasciae occludentes. Both kinds of junction have identical structural elements when visualized in freeze fracture replicas, although the arrangement of these elements differs. Zonulae occludentes consist of networks of branching and anastomosing linear ridges or rows of ∼10 nm particles with 20–30 nm spaces between the rows which form narrow belt-like structures around the apical region of adjacent cells. Fasciae occludentes, on the other hand, consist of similar linear ridges or rows of particles but the junction strands are often discontinuous, open ended and only occasionally intersect with each other. Several different fracture planes through the plasma membrane in the region of the occluding junctions have been observed and these provide further evidence that two components, one from each membrane, fused at the level of the extracellular space, form the junction sealing element. Furthermore, we present evidence which indicates a staggered rather than an in-register arrangement of these two components.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219808
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    Effects of hormone-releasing stimuli on the area of the perivascular space in the neural lobe of the rat (1978)
    Springer
    Cell & tissue research 191 (1978), S. 501-506 
    Details
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Ultrastructure ; Perivascular space ; Hormonerelease ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neural lobes from rats subjected to neurohypophysial hormone-releasing stimuli were examined electron microscopically following fixation in 4 % tannic acid in 2.5 % glutaraldehyde. This fixation allowed the delineation of the perivascular space in the neural lobe tissue. Measurement of the area of the perivascular space showed that it was significantly increased in the rats subjected to vagal stimulation and intraarterial calcium ions compared to the control rats. The rats which had been subjected to haemorrhage as a hormonereleasing stimulus did not show any significant change in the area of the perivascular space. The significance of these findings in relation to hormone release is discussed.
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    URL: http://dx.doi.org/10.1007/BF00219812
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    Lymph node macrophages and reticulum cells in the immune response (1978)
    Springer
    Cell & tissue research 192 (1978), S. 1-23 
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    ISSN: 1432-0878
    Keywords: Lymph node (rat) ; Macrophages ; Dendritic reticulum cells ; Immune response to paratyphoid vaccine ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The reactivity of rat lymph node macrophages and reticulum cells has been studied in relation to the course of the immune response. Special attention was paid to the interdigitating cells (IDC) in the paracortex and the dendritic reticulum cells (DRC) in the germinal centre. Different types of macrophage predominate in the three different phases of the immune response. In the induction phase exudate macrophages predominate. They transform their morphology depending on the micro-environment in which they settle. These cells may contain Birbeck granules. Our experiments suggest, that these granules are immunologically specific organelles, associated with the induction of a primary humoral response. In the proliferation phase transitional cells between newly arrived macrophages and IDC predominate in the paracortex and the number of IDC decreases. In the memory phase IDC repopulate this thymus dependent area, indicating that the characteristic morphology of these cells results from the immune response in the T cell environment. The DRC are specifically related to the germinal centre, the morphological transformation of this peculiar reticulum cell occurs under the influence of the germinal centre reaction. The germinal centre reaction originates by tingible body macrophages (TBM).
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    URL: http://dx.doi.org/10.1007/BF00231019
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    Morphological changes in the esophageal epithelium of the eel, Anguilla japonica, during adaptation to seawater (1978)
    Springer
    Cell & tissue research 192 (1978), S. 25-38 
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    ISSN: 1432-0878
    Keywords: Esophageal epithelium ; Eel ; Seawater adaptation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The esophageal epithelium of the Japanese eel, Anguilla japonica, was studied by light and electron microscopy. In freshwater-adapted eels, longitudinal folds of the mucosal surface are simple in form and lined by a stratified epithelium composed of mucous cells, filament and ribosome-rich cells. Mucous cells are numerous. The filament-rich cells form the outermost and the basal layers of the stratified epithelium and are scattered in the middle zone among the mucous cells. They are firmly bound to one another by many desmosomes and prominent interdigitations of plasma membrane. The distal free surface of the filament-rich cell has a fingerprint-like pattern of microridges. A small number of columnar cells occur at the apices of the folds. They are rich in mitochondria and their distal surfaces bear short microvilli. In seawater-adapted eels, irregularly meandering folds increase the surface area of the mucosa. The stratified epithelium is extensively replaced by a simple columnar epithelium free of mucous cells. The columnar cells resemble in many respects those found in freshwater-adapted eels. They are rich in mitochondria and their distal free surface were provided with short microvilli. However, prominent lateral intercellular spaces and elaborate interdigitations of cytoplasmic processes in the distal zone distinguish the former from the latter. Results are considered in connection with the changes in ion and water permeability of the epithelium after seawater adaptation.
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    URL: http://dx.doi.org/10.1007/BF00231020
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    Ultrastructure of capillaries in the conduction system of the heart in various mammals (1978)
    Springer
    Cell & tissue research 192 (1978), S. 77-87 
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    ISSN: 1432-0878
    Keywords: AV-node ; AV-bundle ; Fenestrated capillary endothelium ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The capillaries in the atrioventricular node and atrioventricular bundle of the heart (mammals) were investigated by thin sections and freezeetch replicas. Fenestrated endothelial cells were found to occur in all mammals examined in this study. These fenestrations (500±50 Å diameter) are bridged by a diaphragm and occur in relatively small sieve areas. In contrast to the AV-node and AV-bundle, the non-specialized myocardium is supplied by continuous capillaries. The presence of the fenestrated capillary in the conduction system of the heart may serve to increase both permeability and passive transport capacity.
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    URL: http://dx.doi.org/10.1007/BF00231024
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    A stereological ultrastructural study of peritoneal macrophages from germ-free and conventionally-reared mice (1978)
    Springer
    Cell & tissue research 192 (1978), S. 157-166 
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    ISSN: 1432-0878
    Keywords: Germ-free mice ; Macrophages ; Peritoneum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The reported work is the first direct ultrastructural comparison of resident peritoneal macrophages from germ-free and conventional animals. Three groups of mice were studied: germ-free (GF), conventionally-reared under isolation conditions (IC), and conventionally-reared in an open environment (OC). The macrophages from the three groups of animals are closely similar morphologically. Particularly noteworthy are the electron-dense, lysosome-like granules which are numerous in the macrophages of germfree mice and which provide a structural foundation for the presumed microbicidal capability of the phagocytes. Morphometric estimates showed that the “average macrophage” from GF mice is smaller and possesses a smaller, rounder nucleus, a smaller volume fraction of mitochondria and more lysosome-like granules per unit of cytoplasmic volume than the “average macrophage” from conventional mice. Moreover, granules and mitochondria are smaller, on average, in the GF phagocytes than in macrophages from conventional mice. The results suggest that peritoneal macrophages from the germ-free mouse represent, more truly than those from the conventional mouse, the nature of the fully differentiated but as yet unstimulated mononuclear phagocyte.
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    URL: http://dx.doi.org/10.1007/BF00231030
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    Ultrastructural analysis of the action of reserpine on the brain neuroendocrine system of the wax moth, Galleria mellonella L., Lepidoptera (1978)
    Springer
    Cell & tissue research 192 (1978), S. 143-155 
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    ISSN: 1432-0878
    Keywords: Neuroendocrine system ; Galleria ; Ultrastructure ; Reserpine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This study concerns the influence of reserpine on the fine structure of peptidergic neurosecretory cells in the pars intercerebralis of Galleria mellonella, and of neurons containing smaller dense-cored vesicles (presumed to be aminergic) localized in the same area of the brain. The drug, administered in doses of 125 μm and 250 μg per g of insect body weight, reduces both the amount and the electron opacity of the dense-cored vesicles with a diameter of 60–80 nm in the neuronal perikarya as well as their terminals. Simultaneously, this treatment evokes an abnormal accumulation of secretory granules within the perikarya of peptidergic neurosecretory cells belonging to three types. This accumulation of secretory material is followed by some changes in the fine structure of these cells. One (fourth) type of neurosecretory cells seems to be insensitive to reserpine action. Participation of the aminergic system in the regulation of the secretory activity of some populations of peptidergic neurosecretory neurons of the insect brain is postulated.
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    URL: http://dx.doi.org/10.1007/BF00231029
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    Structure of the adenohypophysis in parturient female and neonate harp seals, Pagophilus groenlandicus (1978)
    Springer
    Cell & tissue research 192 (1978), S. 341-357 
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    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Cell types ; Neonate ; Parturient ; Harp seal, Phagophilus groenlandicus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pars distalis of parturient harp seals (Pagophilus groenlandicus) is divisible into three distinct zones based on the major cellular components of the different regions. A clear zonation is lacking in neonate seals, the medial “basophilic wedge” and the anterior gonadotrophic were small and difficult to identify. Five cell types were identified based on cytological characteristics: somatotrophs, mammotrophs, thyrotrophs, gonadotrophs and stellate cells; corticotrophs could not be identified, with any certainty, in any of the preparations, nor could the gonadotrophs be classified into LH, FSH, and ICSH cells. The pars intermedia enlarged during the early post-partum period and was large in the parturient females.
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    URL: http://dx.doi.org/10.1007/BF00220751
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    Studies on the ultrastructure and permeability of the hemotrichorial placenta (1978)
    Springer
    Cell & tissue research 192 (1978), S. 391-407 
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    ISSN: 1432-0878
    Keywords: Placenta (rat) ; Permeability ; Tracer ; Intercellular junctions ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of lanthanum chloride and horseradish peroxidase within the full-term chorioallantoic placenta of the rat was investigated 1 to 20 min after administration of these tracers into the maternal blood circulation. Both tracers rapidly penetrate trophoblastic layer I and diffuse into the interspace between layers I and II. They are localized in extensive infoldings and caveolae of the outer surface of layer II. The syncytial character of layer II is confirmed at this developmental stage of the placenta. There is no vesicular uptake or penetration beyond layer II until 20 min after tracer administration. Our results indicate that trophoblastic layer II is the main barrier in the chorioallantoic rat placenta preventing the permeation of macromolecules from maternal to fetal compartments. With freeze-fracturing, particulate structures of variable arrangement and size are found between adjacent cells of layer I. With goniometric analysis small gaps between the appositions of the membrane are observed. These structures are interpreted as tight and/or gap junctions during stages of assembly or disassembly.
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    URL: http://dx.doi.org/10.1007/BF00212321
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    Studies on the ultrastructure and permeability of the hemotrichorial placenta (1978)
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    Cell & tissue research 192 (1978), S. 409-422 
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    ISSN: 1432-0878
    Keywords: Placenta (rat) ; Capillary ; Permeability ; Tracer ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of horseradish peroxidase and lanthanum chloride within the full term chorioallantoic placenta of the rat was examined after administration of these tracers into the umbilical artery. Both tracers rapidly traverse the capillary endothelium. Transendothelial channels, fenestrations and micropinocytotic vesicles provide the main pathways. Intercellular clefts which are either patent or interrupted by leaky intercellular junctions, also contribute to a rapid passage of low and high molecular weight substances. Deep channel-like invaginations, effecting an increase of the exchange area of layer III, are freely accessible to the tracers from the interspace between the capillary endothelium and trophoblastic layer III. The invaginations, however, are not in continuity with the interspace between layers II and III, verifying the syncytial character of layer III. Neither an uptake of the tracers nor a passage across layer III is observed. The main permeability barrier to feto-maternal transfer within the chorioallantoic placenta is localized in the syncytiotrophoblastic layer III. This layer controls the passage of low molecular weight substances and restricts the penetration of high molecular weight substances.
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    URL: http://dx.doi.org/10.1007/BF00212322
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    Immunocytochemical and ultrastructural evidence for a neurophysinergic innervation of the subcommissural organ of the snake Natrix maura (1987)
    Springer
    Cell & tissue research 248 (1987), S. 473-478 
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    ISSN: 1432-0878
    Keywords: Subcommissural organ ; Innervation ; Neu rophysins ; Mesotocin ; Immunocytochemistry ; Ultrastructure ; Snake, Natrix maura
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The subcommissural organ (SCO) of the snake Natrix maura was studied by use of the immunoperoxidase procedure. Primary antisera against bovine neurophysins (Nps I + II, OXY-Np), oxytocin (OXY), mesotocin (MST), arginine-vasotocin (AVT), somatostatin (SOM), β-endorphin (END) and bovine Reissner's fiber were used. A conventional ultrastructural study, with special emphasis on the nerve fibers present in the SCO, was also performed. Nerve fibers containing immunoreactive OXY-Np and MST were seen to reach the SCO. The staining of adjacent sections with the anti-Reissner's fiber serum showed that the OXY-Np- and MST-immunoreactive fibers were distributed among the cell bodies and processes of the ependymal secretory cells. No fibers containing immunoreactive OXY, AVT, SOM or END were found in the SCO. The ultrastructural analysis revealed in the SCO the presence of nerve fibers filled with electron-dense granules, 170–210 nm in diameter. Although a direct apposition between these fibers and the SCO cells was frequently seen, no synaptic differentiations were identified. Structures identical to the Herring bodies (found in the neurohypophysis) were seen in the SCO.
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    URL: http://dx.doi.org/10.1007/BF00218215
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    ‘Neurosecretion’ by a classic cholinergic innervation apparatus (1987)
    Springer
    Cell & tissue research 249 (1987), S. 421-425 
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    ISSN: 1432-0878
    Keywords: Cholinergic synapses ; Ultrastructure ; Exocytosis ; Non-synaptic release ; Neuropeptides ; Carassius auratus ; Rana pipiens ; Wistar white rat ; Hamster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Nerve terminals forming typical synapses with adrenal chromaffin tissues have been examined in the goldfish, frog (Rana pipiens), hamster and rat. Presumptive secretory inclusions present in the terminals are of two distinct types. Electron-lucent synaptic vesicles 30–50 nm in diameter are densely clustered adjacent to membrane thickenings and presumably discharge their contents into the synaptic clefts. Secretory granules (i.e. large dense-cored vesicles) 60–100 nm in diameter are more abundant in other parts of the terminals. Sites of granule exocytosis have been observed in each of the animals investigated. They are usually encountered within apparently undifferentiated areas of plasmalemma and only rarely occur within synaptic thickenings. Granule exocytosis from within synaptic terminals and chromaffin gland cells is most readily observed in specimens exposed, prior to fixation, to saline solutions containing both tannic acid, and 4-aminopyridine and/or elevated levels of K+. These findings show that the pattern of secretory discharge, involving both synaptic and non-synaptic release, which is widespread in invertebrate central nervous systems, is also characteristic of vertebrate, peripheral cholinergic terminals.
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    URL: http://dx.doi.org/10.1007/BF00215526
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    Glomerular ultrastructure of the trout, Salmo gairdneri: Effects of angiotensin II and adaptation to seawater (1987)
    Springer
    Cell & tissue research 249 (1987), S. 437-442 
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    ISSN: 1432-0878
    Keywords: Angiotensin II ; Glomerulus ; Salmo gairdneri ; Seawater-adaptation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of angiotensin infusion on the glomerular ultrastructure of freshwater- and seawater-adapted rainbow trout, Salmo gairdneri, has been examined by scanning and transmission electron microscopy. Adaptation of trout to seawater resulted in epithelial podocyte flattening, primary process broadening and apparent loss of foot processes in almost all glomeruli, features which were uncommon in freshwater-adapted trout. Similar changes were induced by infusion of freshwater-adapted animals with angiotensin, suggesting that the renin-angiotensin system plays a role in the modification of glomerular epithelial ultrastructure. Adaptation of trout to seawater also reduced glomerular diameter, but infusion of freshwater-adapted animals with angiotensin did not mirror this effect. Infusion of angiotensin into seawater-adapted animals increased the overall thickness of glomerular basement membrane by increasing the lamina rara interna and lamina densa. This did not occur when freshwater-adapted fish were either infused with angiotensin or adapted to seawater. These findings suggest that other humoral systems are involved in the control of glomerular diameter and basement membrane thickness as part of an integrated response to increased environmental salinity.
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    URL: http://dx.doi.org/10.1007/BF00215528
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    Ultrastructural analysis of the effect of ethane dimethanesulphonate on the testis of the rat, guinea pig, hamster and mouse (1987)
    Springer
    Cell & tissue research 249 (1987), S. 451-457 
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    ISSN: 1432-0878
    Keywords: Leydig cells ; Ethane dimethanesulphonate ; Ultrastructure ; Degeneration ; Resistance ; Rodents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphological response of the testis of rats, guinea pigs, Syrian hamsters and mice to treatment with the cytotoxin ethane dimethanesulphonate was examined using light and electron microscopy. One to two days after a single administration of ethane dimethanesulphonate to adult rats, guinea pigs, and hamsters, the Leydig cells showed marked ultrastructural alterations suggestive of degeneration and cell death. The former alterations included karyopyknosis, cytoplasmic vesiculation and accumulation of lipid inclusions and large lipofuscin bodies. Fragments of necrotic Leydig cells were often engulfed by the interstitial tissue macrophages. The morphology of the seminiferous epithelium of these three species was unchanged from the morphology observed in vehicle-injected control animals. In contrast, multiple injections of ethane dimethanesulphonate given to mice produced no ultrastructural alterations to Leydig cells yet the seminiferous epithelium exhibited disruption of spermatogenesis. Although the Leydig cells of the mouse appear resistant to ethane dimethanesulphonate, this agent exerts a selective cytotoxic action upon Leydig cells of the rat, guinea pig and hamster thus identifying ethane dimethanesulphonate as a useful chemical for future endocrine and physiological studies of testicular function in three common laboratory species.
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    URL: http://dx.doi.org/10.1007/BF00215530
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    Intercellular spaces between macula densa cells: An ultrastructural study comparing high pressure perfusion fixation with in situ drip-fixation of rat kidney (1987)
    Springer
    Cell & tissue research 250 (1987), S. 461-464 
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    ISSN: 1432-0878
    Keywords: Macula densa ; Intercellular spaces ; Ultrastructure ; Frusemide ; Tubulo-glomerular feedback ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In situ drip-fixation of superficial glomeruli and tubules in the rat kidney verified the results obtained from high pressure perfusion fixation studies indicating that distinct spaces normally exist between the cells of the macula densa. Following treatment with frusemide these intercellular spaces between the macula densa cells became closed in both drip-fixed and perfusion-fixed kidneys. These findings suggest that the variability of extracellular compartmentation found in the macula densa is unlikely to be an artifact but most likely represents changes in the in vivo status of the macula densa.
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    URL: http://dx.doi.org/10.1007/BF00219092
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    Control of the pars intermedia of the lizard, Anolis carolinensis (1978)
    Springer
    Cell & tissue research 186 (1978), S. 241-258 
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    ISSN: 1432-0878
    Keywords: Neural lobe ; Anolis carolinensis ; Ultrastructure ; Intermediate lobe control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the neural lobe of the lizard, Anolis carolinensis, was studied after fixation in a threefold aldehyde solution. The neural lobe appeared as narrow vertical diverticula separated from one another and from the pars intermedia by a continuous vascular septum. No nerves passed through this septum. The ependymal, fibrous and external layers were readily recognized. Peptidergic fibres were the main component of the fibrous layer. The peptidergic endings were in intimate contact with the ependymal cells, suggesting that the ependyma mediates the release of neural lobe peptides. The external layer contained ependymal end-feet and numerous aminergic terminals, ending directly on the perivascular basal lamina and/or on the ependymal end-feet. The functional aspects are discussed in terms of intermediate lobe control. The findings suggest that aminergic substances take part in the control of the intermedia, but do not exclude the involvement of peptide hormones.
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    URL: http://dx.doi.org/10.1007/BF00225534
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    Ultrastructure and lipid content of the liver of the zebrafish, Brachydanio rerio, related to vitellogenin synthesis (1978)
    Springer
    Cell & tissue research 186 (1978), S. 297-308 
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    ISSN: 1432-0878
    Keywords: Liver ; Teleost ; Ultrastructure ; Lipid ; Vitellogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The female zebrafish is capable of producing mature eggs on the fifth day of each reproductive cycle. During this five-day period the ultrastructure of hepatocytes undergoes several changes. The number of nuclear pores increases rapidly during spawning, followed by a proliferation of RER within 24 h. Two days after spawning, glycogen has disappeared and the liver contains large amounts of lipids. The lipid droplets are closely surrounded by elongated mitochondria. Golgi complexes are abundant, secreting dense bodies. Four days after spawning the hepatocytes tend to regain their pre-spawning appearance. It is suggested that the changes in the hepatocytes, which coincide with special phases of ovarian activity, are related to vitellogenin synthesis. Steroids, especially estradiol-17β, may trigger this process in the liver.
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    URL: http://dx.doi.org/10.1007/BF00225539
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    An ultrastructural study of the larval integument of the midge, Chironomus riparius meigen (Diptera: Chironomidae) (1978)
    Springer
    Cell & tissue research 186 (1978), S. 327-335 
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    ISSN: 1432-0878
    Keywords: Cuticle ; Epidermis ; Chironomus ; Respiration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The larval integument of the midge, Chironomus riparius Mg., is unusually thin although it conforms with the normal insect pattern. The cuticle of the post-cephalic segments is about 3 μm thick and overlies an epidermis which has an irregular basal plasma membrane resulting in spaces occurring between it and the basement membrane. The ventral tubuli have a similar epidermis but the cuticle is somewhat thinner. The anal papillae have the thinnest cuticular covering with a uniquely folded epicuticle of variable thickness, and their epidermis has the characteristics of a transporting epithelium. No evidence of pore canals could be found in the cuticle of any part except the head capsule which has a remarkably smooth epicuticle and a distinct layer which may represent the exocuticle. There are no spaces between the basement membrane and basal plasma membrane of the epidermis in the head. Ultrastructural evidence would suggest that gaseous exchange can occur across most of the post-cephalic integument.
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    URL: http://dx.doi.org/10.1007/BF00225541
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    Effects of systemic administration of 6-hydroxydopamine on the circumventricular organs in nonhuman primates (1978)
    Springer
    Cell & tissue research 187 (1978), S. 115-127 
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    ISSN: 1432-0878
    Keywords: Area postrema ; 6-Hydroxydopamine ; Degenerative changes ; Ultrastructure ; Cynomolgus and squirrel monkeys
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 6-Hydroxydopamine (6-OH-DA) has been shown to produce degenerative changes in noradrenergic nerve terminals and preterminals in the CNS following intracisternal, intraventricular or direct injection into the brain parenchyma. Systemic injection of 6-OH-DA is known to result in degenerative changes in noradrenergic terminals in the peripheral nervous system. However, only a few studies have been carried out on the effects of systemic injections of 6 OH-DA on noradrenergic terminals in the CNS. In the present study cynomolgus and squirrel monkeys were injected intravenously on two successive days with total doses of 350mg/kg and 150 mg/kg of 6-OH-DA, respectively, and sacrificed at 2 and 24 h following the second injection. Degenerative changes in the area postrema (AP) neurons in all injected animals were characterized by a generalized increase in electron density of cytoplasmic elements in axonal terminals and preterminals. Multilamellar bodies, clusters of clear and dense core vesicles, increased numbers of secondary lysosomes, and an increase in the number of glycogen granules were observed in these structures. In astrocytes the amount of glycogen increased markedly in injected animals, but no other glial alterations were observed. The number of mast cells in the AP was greater in injected than in noninjected animals, both in the perivascular spaces (PVS) and in parenchymal locations. Cell processes in the PVS were occasionally observed to contain electron dense bodies, and degenerative changes were seen in supraependymal processes in some injected animals.
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    URL: http://dx.doi.org/10.1007/BF00220623
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    Osteodentine and vascular osteodentine of Anarhichas lupus (L.) (1978)
    Springer
    Cell & tissue research 187 (1978), S. 135-146 
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    ISSN: 1432-0878
    Keywords: Osteodentine ; Anarhichas lupus ; Ultrastructure ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Le tissu dentinaire d'Anarhichas lupus s'est révélé être une ostéodentine vasculaire. Les études en MET, MEB et diffraction X montrent l'hétérogénéité de ce tissu. L'aspect désordonné des fibres de collagène, incomplètement minéralisées (leur striation est encore bien visible), explique la complexité de la répartition des cristaux puisqu' elles en déterminent l'ordonnance. La minéralisation imparfaite du tissu, dont témoignait déjà la striation visible du collagène, est confirmée par l'analyse des poudres en diffraction X (la cristallinité de l'ostéodentine vasculaire est nettement inférieure à celle de la couche de tissu dentaire périphérique) et par l'examen en MET de haute résolution, aucun réseau cristallin n'ayant pu être mis en évidence. L'ostéodentine, l'os basal et l'os profond ont en commun une phase minérale, avec une organisation plus ou moins bonne, différente du système des apatites.
    Notes: Summary TEM, SEM and X-ray diffraction analysis demonstrate the heterogeneity of the dentinal tissue of Anarhichas lupus, a vascular osteodentine. The disordered aspect of collagen fibres, incompletely mineralized (the periodical striation being still visible), explains the scattered distribution of crystallites since they are responsible for their arrangement. The low degree of mineralization revealed by the visible collagen striation is confirmed by X-ray diffraction analysis (the crystallinity of vascular osteodentine being much lower than that of the peripheral dental tissue) as well as by high resolution TEM, since no lattice planes could be observed. Osteodentine, supporting bone and proper bone have in common a mineral phase, more or less organized, different from the apatite system.
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    The ultrastructure and renewal of the intestinal epithelium of the juvenile grasscarp, Ctenopharyngodon idella (Val.) (1978)
    Springer
    Cell & tissue research 187 (1978), S. 181-200 
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    ISSN: 1432-0878
    Keywords: Intestine ; Teleost ; Epithelium ; Renewal ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The intestinal absorptive epithelium of starved and fed fish has been studied electron microscopically. After feeding, cells of the proximal segment of the intestine show morphological characteristics of lipid absorption. Absorptive cells in the middle segment contain many pinocytotic vesicles in both fasted and fed specimens. Absorption of protein macromolecules is supposed to be one of the main functions of this part of the gut. In the most caudal part of the intestine, absorptive cells carry relatively few and short microvilli. The proximal and distal segments show structural indications of a function in osmoregulation. The renewal of the epithelium has been studied with light microscopic autoradiography, using tritiated thymidine. The intestinal mucosal fold epithelium represents a cell renewal system. The cells proliferate at the base of the fold and migrate towards the apex in 10–15 days at 20° C. The functional absorptive cells proved to be generally present in the intestinal epithelium, including the proliferative area. Undifferentiated cells have not been identified. The results will be compared with data on absorption of lipid and protein macromolecules in teleostean and mammalian intestines and with descriptions of the cell renewal system in the mammalian intestine.
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    The ultrastructure of the non-neurosecretory components in the brain of the midge, Chironomus riparius Mg. (Diptera: Nematocera) (1978)
    Springer
    Cell & tissue research 187 (1978), S. 355-366 
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    ISSN: 1432-0878
    Keywords: Neuron ; Glial ; (Insect, Chironomus riparius) ; Extracellular space ; Perineurium ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the neural sheath, glial cells and neurons in the brain of the neoimaginal male Chironomus riparius is described. The neural sheath comprises a neural lamella and underlying perineurium. The neural lamella consists of an amorphous matrix in which fine fibrils occur. The perineurium is composed of two cell types forming a continuous layer around the brain. The subjacent cortical layer, composed of the cell bodies of neurons and glial cells, varies considerably in thickness and surrounds the centrally located neuropiles. Three types of glial cells are distinguished on the basis of their positions and appearances. Five types of neurons are described which differ in size and relative frequency of organelles. Four types of axons, including those of neurosecretory cells, are distinguished by their size and content.
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    The posterior pituitary of the garden dormouse (Eliomys quercinus L.) (1978)
    Springer
    Cell & tissue research 188 (1978), S. 189-204 
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    ISSN: 1432-0878
    Keywords: Neural lobe of hypophysis ; Hibernating mammals ; Ultrastructure ; Neurosecretory granules ; Whorls
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'ultrastructure de la posthypophyse du Lérot a été examinée à différents stades du cycle annuel de ce rongeur hibernant. Il n'a pas été observé de différences évidentes entre les stades étudiés, et sont donc présentées ici les caractéristiques générales retrouvées chez tous les animaux. Les axones neurosécréteurs et leurs terminaisons peuvent être divisés en deux catégories suivant l'aspect des grains de neurosécrétat et des microvésicules présents. Le premier type contient des grains arrondis, à contenu d'apparence homogène, avec des microvésicules rondes. Dans les autres axones, les grains sont de forme variable, souvent allongés, et leur contenu présente deux sortes d'organisations cristallines; les microvésicules y sont en majorité aplaties. Considérant comme improbable que cette dualité résulte seulement d'un artefact, trois hypothèses sont envisagées. La dualité d'aspect des grains peut être liée à leur contenu en hormone (ocytocine ou vasopressine); ou bien l'aspect des grains peut correspondre à leur degré de maturation. Il est possible aussi que ces explications soient toutes deux valables. Par ailleurs, les pituicytes du Lérot contiennent fréquemment un réticulum endoplasmique organisé en lamelles concentriques (whorls). La signification de ces formations reste pour l'instant obscure.
    Notes: Summary Ultrastructural examination of the posterior pituitary of the garden dormouse (Eliomys quercinus L.) was carried out at different times in the annual cycle of this hibernating rodent. Obvious differences between experimental groups have not been observed, and the results presented here must be considered as general features of the garden dormouse posterior pituitary. Neurosecretory axons and endings can be divided into two types, according to different aspects of neurosecretory granules (NSG) and microvesicles (MV). One type contains spherical NSG with homogeneous cores and round MV. In the other type, NSG have various, often elongated, shapes. Their content shows two types of crystalline structures and most of the MV have flattened aspects. As it is very unlikely that this duality in NSG is a result of an artefact of fixation, three hypotheses are presented as explanation. The duality of NSG might be related either to their hormonal content (oxytocin or vasopressin) or to their degree of maturation. Moreover, both explanations may be valid. In the species studied, pituicytes often contain concentric lamellar structures of the endoplasmic reticulum (whorls), the significance of which remains obscure.
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    Ovarian follicles of normal NMRI mice and homozygous “Nude” mice (1978)
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    Cell & tissue research 188 (1978), S. 409-426 
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    ISSN: 1432-0878
    Keywords: Ovary ; “Nude” mouse ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ovarian follicles of juvenile (15-day and 21-day old), pubescent (28-day old) and sexually mature (45-day old) “Nude” mice have been compared to those from normal NMRI mice of the same age and breeding groups. At the electron microscopical level, some differences were observed in both follicular cells and oocytes. In the follicular cells, the following alterations could be seen in the “Nude” ovaries: (1) the differentiation between clear and dark cells, normally not occurring before the age of 21 days, was already present in the 15-day old “Nude” mice and (2) the follicular intercellular spaces were frequently dilated, possibly because of a contraction of the cells, even in the small growing follicles of the bilaminar type in the athymic animals. The “Nude” oocytes could be characterized by (1) a precocious appearance and an early disappearance of the nuage material, (2) a nearly complete absence of micropapillae on the oolemma, (3) a dense and disseminated aspect of their Golgi complexes, (4) the presence of a large amount of multivesicular bodies and (5) of tiny (about 30 nm) dense membrane-bounded particles in their ooplasm. These differences are discussed in relation to the possible interference of congenital athymia with the development of the hypothalamo-pituitary-gonadal axis. However, the influence of the reduced immunological responsiveness of the “Nude” mice on their ovarian development cannot be excluded for animals raised in a normal — and consequently infected — environment.
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    Histological and cytological studies on the fat body of the cockroach Nauphoeta cinerea during the first reproductive cycle (1978)
    Springer
    Cell & tissue research 188 (1978), S. 481-490 
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    ISSN: 1432-0878
    Keywords: Fat body ; Cockroach ; Reproductive cycle ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The central fat body of the ovoviviparous cockroach Nauphoeta cinerea was studied during the first reproductive cycle of the female by means of light microscopy, autoradiography and electron microscopy. Comparative studies in larval stages were also undertaken. The fat body of Nauphoeta contains a large amount of lipid droplets and the remaining cytoplasm is very scarce. The cytological cyclicity of the fat body is consistent with the known biochemical rhythms of vitellogenin production. The proteosynthetic apparatus appears about 3 days after imaginal ecdysis, along with vitellogenin. The ribosomal endoplasmic reticulum (RER) shows a tremendous increase by the 7th day of the first cycle. The most active period of vitellogenin production lasts from day 7 to day 12. The proteosynthetic apparatus then returns to an inactive stage and disappears. This inactive condition lasts to the end of the gestation period. The autoradiographic results are consistent with the cytological features.
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    The ultrastructure and function of follicle cells in Foucartia squamulata (Herbst) (Curculionidae) (1978)
    Springer
    Cell & tissue research 189 (1978), S. 347-353 
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    ISSN: 1432-0878
    Keywords: Vitelline membrane ; Chorion ; Ultrastructure ; Curculionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The follicle cells of Foucartia squamulata are involved in the formation of both vitelline membrane and chorion. Precursors for these egg coverings are synthesized by the rough endoplasmic reticulum and condensed within dictyosomes. The vitelline membrane and the chorion appear on the oocyte surface simultaneously, which is an unusual phenomenon for insects. The follicular epithelium has not been found to contribute to vitellogenesis in the species under study.
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    Oogenesis in Acerentomon gallicum Jonescu (Protura) (1978)
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    Cell & tissue research 189 (1978), S. 365-374 
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    ISSN: 1432-0878
    Keywords: Previtellogenesis ; Oocyte ; Ultrastructure ; Acerentomon gallicum ; Protura
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary At the onset of previtellogenesis, the oocytes of Acerentomon gallicum begin to grow and increase their content of organelles. The nuage material in the oocytes at first increases in amount, then declines gradually to disappear completely from oocytes that have attained 50 μm in diameter. During the growth period, new dictyosomes, mitochondria and ribosomes appear. Numerous vesicles become detached from the cell membrane and subsequently fuse into cisternae, thus forming extensive complexes of the rough endoplasmic reticulum. In oocytes with diameters between 50 and 100 μm the Golgi complexes show a considerable increase in activity, and many lamellar bodies arise from mitochondria that have undergone specific transformation.
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    Tormogen cell and receptor-lymph space in insect olfactory sensilla (1978)
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    Cell & tissue research 189 (1978), S. 549-554 
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    ISSN: 1432-0878
    Keywords: Tormogen cell ; Receptor-lymph space ; Chemoreceptor ; Ultrastructure ; Histochemistry ; Calliphora (Insects)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary (1) The basiconic sensilla on the antennae of Calliphora resemble other insect epidermal sensilla; one or several bipolar sense cells are surrounded by three non-neural cells. (2) The apical cell membrane of the tormogen cell(one of the three accessory cells) forms microvilli coated internally with particles. (3) In the (extracellular) outer receptor-lymph space hyaluronic acid can be demonstrated histochemically. (4) Demonstration of non-specific alkaline phosphatase, Mg2+-activated ATPase, and the presence of mitochondria in the apical part of the tormogen cell suggest active transport processes through these cells into the outer receptor-lymph space.
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    Kinetics of functional and morphological changes during decoupling and recoupling induced by glycerol in isolated muscle fibres of the crayfish (1978)
    Springer
    Cell & tissue research 192 (1978), S. 167-185 
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    ISSN: 1432-0878
    Keywords: T-system tubules ; Glycerol procedure ; Structure-activity relationship ; Ultrastructure ; Astacus fluviatilis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of ultrastructural changes in the T-system of isolated muscle fibres of the crayfish by the glycerol procedure is described in correlation with the dissociation of excitation-contraction (E-C) coupling as well as with recoupling of the E-C link. The sequence of events in the process of disconnection of the tubules is as follows: dilation of the T-system tubules, disconnection of the constricted tubular segments from the surface membrane and from the T-system vesicle, disappearance of the lumen and its disintegration. The decoupled state is characterised by the presence of round vesicles uniformly distributed in the entire volume of the fibre. The volume of vesicles accounts well for the residual postglycerol volume increase (15%) of the muscle fibres. Functional and structural recovery can be induced by reapplication of glycerol to fibres decoupled and vesiculated with concentrations of glycerol≦300mmol · l-1 in crayfish saline. The restitution starts with the organisation of the material of the disintegrated connecting segment of the T-system tubule into small vesicles which coalesce to form the tubule from the vesicular site. At the same time the surface membrane is invaginated toward the vesicle, thus forming the tubule from the surface membrane site. Recovery starts already in the first minute after application of glycerol and is completed within approximately 15min.
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    Ultrastructural cytochemical localization of adenylate cyclase in the early chick embryo (1987)
    Springer
    Cell & tissue research 247 (1987), S. 465-468 
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    ISSN: 1432-0878
    Keywords: Adenylate cyclase ; Cytochemistry ; Gastrulation ; Ultrastructure ; Chick embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Adenylate cyclase activity was localized in various tissues of the early chick embryo using an ultrastructural histochemical technique. Reaction product was deposited on the lateral plasma membrane of all cells, but with a preferential localization at the apical terminal complex in the epiblast. There was no activity associated with the free surfaces of these or other cells in the embryo. Intracellular deposits were found in all cells associated with the endoplasmic reticulum, nuclear envelope and Golgi bodies. In the last organelle, the deposit was sometimes observed to be distributed through the stack in a non-uniform way, with the heaviest deposits occurring at the forming face. No clear difference could be detected between the cytochemical activity associated with cells in various regions of the embryo, or with embryos at different stages of early development.
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    Gonadotropin production and release in female goldfish (Carassius auratus) after administration of pimozide and an LHRH analogue as studied by electron microscopy and radioimmunoassay (1987)
    Springer
    Cell & tissue research 247 (1987), S. 477-482 
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    ISSN: 1432-0878
    Keywords: Gonadotropic cells ; LHRH analogue ; Pimo-zide ; Ultrastructure ; Goldfish ; Carassius auratus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of pimozide and an LHRH-analogue (LHRH-A) on gonadotropic cells of the goldfish pituitary gland were described qualitatively and quantitatively. A scale of four categories was devised to reflect various ultrastructural appearances of the cells. Experimental animals were divided into a control group, a group injected with LHRH-A alone, pimozide alone, and groups receiving these two substances in combination. Fish injected with the single substance were killed 12 h after injection while the groups receiving the combined treatments were killed at 4, 12 and 48 h. Serum levels of gonadotropin measured by radioimmunoassay were used to indicate whether an increase in hormone release had occurred. An immunocytochemical technique, the protein A-gold procedure, assured that the cells studied were gonadotropes. The control group showed variation in the profiles of gonadotropic cells. The single treatment groups showed some increase in secretory inclusions. At 4 h after injection the combined treatment caused a significant increase in hormone granules; at 12 and 48 h there was a gradual decrease in content of secretory products, and an increase in vacuolization. The results indicate that the combined pimozide and LHRH-A treatment stimulated gonadotropin production as well as release.
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    Light- and electron-microscopic study of the endolymphatic sac of the tree frog, Hyla arborea japonica (1987)
    Springer
    Cell & tissue research 249 (1987), S. 57-62 
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    ISSN: 1432-0878
    Keywords: Endolymphatic sac ; Calcium carbonate ; Otoconia ; Ultrastructure ; Frog (Hyla arborea japonica)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The endolymphatic sac of the tree frog and its crystals were observed by light- and electron microscopy. Scanning electron microscopy revealed that the crystals have a faceted body and two pointed ends. Light- and transmission electron microscopy revealed that the endolymphatic sac is composed of many small chambers. In their lumina, numerous “ghosts” of crystals that resulted from decalcification were observed. The ghosts were demarcated by a linear dense material or embedded in a flocculent substance. The epithelium of the endolymphatic sac is simple squamous or cuboidal and peculiar cytoplasmic granules are found in most cells. The granules are surrounded by a limiting membrane and have varying electron density. Some granules contain a core and/or tubular structures. Vacuoles containing large ghosts are also found in the epithelial cells. These ghosts were quite similar to those in the lumen and sometimes coexist with cell debris. The fine structure of the endolymphatic sac and its crystals is discussed.
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    The intracellular pathway of antagglutinin secretion in the boar caput epididymidis as revealed by immunogold labelling (1987)
    Springer
    Cell & tissue research 249 (1987), S. 89-99 
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    ISSN: 1432-0878
    Keywords: Epididymis ; Immunogold technique ; Ultrastructure ; Protein secretion ; Antagglutinin ; Boar
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Antagglutinin, a specific protein synthesized by the boar epididymis, was localized by an ultrastructural immunogold-labeling procedure in the principal cells of the three regions of the caput epididymidis, most notably at the sites of synthesis and secretion. The intensity of the reaction was variable in the three epididymal zones. Labeling was of low intensity in the proximal and middle caput, except in the granules of the latter. These granular “storage sites” did not correspond to typical secretory granules but appeared to be intracellular sites of degradation of this protein. In the distal caput, which was devoid of these granules, intense secretory activity for antagglutinin was detected. Few gold particles were localized in the RER profiles but labeling was detected in the Golgi zone, in numerous dense vesicles, in structures distributed between the Golgi zone and the apex of the cell, and in the epididymal lumen. This study has enabled us to visualize immunocytochemically antagglutinin along its intracellular secretory pathway, i.e. at the site of its synthesis, during its passage via the Golgi zone, and its intracellular transport to the lumen.
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    Separation and maturation of gonadotrophs from 2A8 clonal cells in vitro (1978)
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    Cell & tissue research 189 (1978), S. 31-40 
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    ISSN: 1432-0878
    Keywords: Pituitary cell clone ; LHRH-Sepharose ; Gonadotrophs ; Hypertrophy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 2A8 clonal cells derived from the epithelium of Rathke's pouch of fetal rats were cultured in growth medium supplemented with fresh rat serum, median-eminence extract and l-thyroxine. Then, in order to isolate gonadotrophs, cyanogen bromide-activated Sepharose which was conjugated with LHRH (LHRH-Sepharose) was added to the culture medium. Fourteen days after incubation of 2A8 cells with LHRH-Sepharose, agranular and granular cells were rapidly bound to LHRH-Sepharose when fresh serum had previously been added in the medium. The cytoplasm of granular cells that were bound to LHRH-Sepharose contained spherical secretory granules (200–250 nm in diameter). These cells were similar in morphology to the FSH and LH gonadotrophs described by Kurosumi (1968). Moreover, many of them appeared as hypertrophied cells that resembled “castration” cells. These results demonstrate that LHRH conjugated to Sepharose can be used to separate gonadotrophs from other 2A8 cells, and it is suggested that the hypertrophy of some cells might be due to persistent stimulation by LHRH which is likely bound to receptors on the cell membrane.
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    The ultrastructure of the herring bodies in rats subjected to different experimental conditions (1978)
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    Cell & tissue research 189 (1978), S. 41-51 
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    ISSN: 1432-0878
    Keywords: Herring bodies (rat) ; Colchicine ; Cold ; Neurosecretion ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A study of the morphology of Herring bodies of the posterior pituitary lobe of rats treated with colchicine and/or exposed to low temperatures has been performed. After treatment with colchicine (20 μg in distilled water injected intracisternally) a predominance of Herring bodies with a large number of small “synaptic-like” vesicles surrounded by neurosecretory granules is found. Exposures to low temperature (4–6° C) result in an increase in the neurosecretory material and the Herring bodies show many neurosecretory granules of different densities. After treatment with colchicine and subsequent exposure to low temperatures, the Herring bodies are characterized by having a great number of autophagic bodies which become more numerous as the length of the exposure is increased; later autophagic vacuoles and lamellar bodies become evident.
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    The ultrastructure and histochemistry of the mesenteric connective tissue of the cockroach Periplaneta americana L. (Insecta, Dictyoptera) (1978)
    Springer
    Cell & tissue research 189 (1978), S. 91-107 
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    ISSN: 1432-0878
    Keywords: Connective tissue sheath ; Periplaneta ; Ultrastructure ; Histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé La gaine conjonctive épaisse entourant l'intestin moyen de la Blatte Periplaneta americana a été étudiée en faisant appel à la microscopie photonique, électronique et l'histochimie. Cette couche conjonctive, reliée à l'épithélium mésentérique par une lame basale, traversée par des faisceaux musculaires, des trachées et des nerfs, contient de très nombreuses fibrilles de collagène, des fibrilles élastiques, des fibroblastes et des hémocytes. Au cours des premiers stades le matériel conjonctif est élaboré par des fibroblastes. Différentes réactions, en particulier le bleu alcian, la métachromasie et les digestions enzymatiques ont montré la présence de glycosaminoglycanes. La présence d'acide hyaluronique à tous les stades, l'apparition et l'augmentation des composés sulphatés ainsi que la présence de glycoprotéines ont été mises en évidence.
    Notes: Summary The thick layer of collagenous connective tissue around the mesenteron of the cockroach Periplaneta americana has been examined by light microscopy, electron microscopy and histochemical techniques. This sheath, connected to the mesenteric epithelium by a basal lamina and traversed by longitudinal and circular musculature, tracheae and nerves, contains numerous collagen fibrils, elastic fibers, fibroblasts and rare hemocytes. Development starts during the first instars with the production of connective tissue material by fibroblasts. Glycosaminoglycans have been observed with the use of various histochemical reactions, in particular alcian blue staining, metachromasia and enzymatic digestion. The reactions indicate the presence of hyaluronic acid in the various instars, the appearance and increase of sulphated components during development, and the presence of neutral glycoproteins.
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    An ultrastructural study of periderm granules in the regenerating feather of the jungle fowl (1978)
    Springer
    Cell & tissue research 192 (1978), S. 319-326 
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    ISSN: 1432-0878
    Keywords: Periderm granules ; Regenerating feather ; Ultrastructure ; Jungle fowl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Periderm granules in the support cells of regenerating feathers of mature male Jungle Fowls were studied ultrastructurally and histochemically. Histochemical results showed the absence of carbohydrate and lipid, and the presence of protein in the periderm granules. The periderm granules were measured at successive levels of feather regeneration. The mean size of the periderm granules increased significantly as the regenerating feather matured, and this observation was suggestive of a storage function, perhaps of surplus or waste protein. The cells in which the periderm granules are found also contain glycogen. There are numerous desmosomal junctions on their interdigitating plasma membranes. These transient cells may collect waste, provide nutrition, and serve as a protective barrier for the definitive cells of the regenerating feather.
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    A further type of transient cytoplasmic organelle in human spermatids (1978)
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    Cell & tissue research 192 (1978), S. 359-361 
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    ISSN: 1432-0878
    Keywords: Spermatids ; Human ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Osmiophilic granules with surrounding vesicles resembling flower-like structures occur transiently during the differentiation of human spermatids. These organelles are incorporated into the residual bodies when mature spermatids are released from the germinal epithelium.
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    URL: http://dx.doi.org/10.1007/BF00220752
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    Segmental variations in the organization of the endoplasmic reticulum of the rat nephron (1987)
    Springer
    Cell & tissue research 247 (1987), S. 215-225 
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    ISSN: 1432-0878
    Keywords: Kidney ; Endoplasmic reticulum ; Ultrastructure ; Membrane transport ; Metabolism ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The spatial organization of endoplasmic reticulum (ER) was examined in all segments of rat nephron. Tissues were fixed with glutaraldehyde, impregnated “en bloc” with osmium tetroxide, prepared for and examined by standard (80–100 kV) and high voltage (1 mEV) transmission electron microscopy. In all proximal tubule cells, ER forms a continuous and extensive network of canaliculi and abundant fenestrated saccules which surround mitochondria and cytoplasmic bodies; the cage-like structure of the fenestrated saccules was most evident around the spherical mitochondria of the S3 segment. In the cells of the distal straight and convoluted tubules, the network consists mostly of canaliculi with rare non-fenestrated saccules. The ER network of canaliculi is particularly rich in intercalated cells, in contrast with its rudimentary appearance in the adjacent principal cells of the collecting tubule. In fact, in these cells there are few isolated ER cisternae and they are rarely impregnated. The nuclear envelope is well impregnated in most cells throughout the various segments. Segmental variations in ER organization and its relative abundance are most likely related to the well, established functional heterogeneity of the nephron segments. Moreover, the extensive and unique organization among mitochondria, ER and the basolateral membrane suggests that these three organelles function as a unit which is related to active electrolyte transport. In addition, because of its transepithelial organization, ER may well constitute a transcellular pathway for molecules.
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    URL: http://dx.doi.org/10.1007/BF00216564
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    Sacciform cells in the epidermis of the brown trout, Salmo trutta, and the Arctic char, Salvetinus alpinus (1987)
    Springer
    Cell & tissue research 247 (1987), S. 259-265 
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    ISSN: 1432-0878
    Keywords: Epidermis ; Acidophilic cell ; Histochemistry ; Ultrastructure ; Salmo trutta ; Salvelinus alpinus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sacciform cells containing an acidophilic, proteinaceous secretion, were identified in the epidermis of the brown trout and Arctic char. This cell type increased in number during the chronic stages of infestation by the ectoparasitic flagellate, Ichthyobodo sp., in immature brown trout, and decreased during sexual maturation in male brown trout and char. It is suggested that the salmonid sacciform cell produces a secretion which protects the fish against infestation or damage by skin parasites.
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    URL: http://dx.doi.org/10.1007/BF00218307
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    Ultrastructural study of the long-term development of two experimental cutaneous calcinoses (topical calciphylaxis and topical calcergy) in the rat (1987)
    Springer
    Cell & tissue research 247 (1987), S. 525-532 
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    ISSN: 1432-0878
    Keywords: Calcergy ; Calciphylaxis ; Cutaneous calcinosis ; Experimental calcification ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Skin calcification induced by topical calciphylaxis was provoked by a subcutaneous injection of iron chloride in rats previously sensitized by dihydrotachysterol. A cutaneous topical calcergy was induced by an injection of potassium permanganate. An electron-microscopical study of the long-term evolution of both these models of calcification was made. After the initial stages, mineralization of the connective tissue continued by a secondary nucleation process without matrix vesicles. The mineral composed of needle-like structures, apatite in nature, was mainly deposited between and around collagen fibrils, and showed various arrangements in calcified plaques. Intrafibrillar calcification was rarely observed and appeared only in the later stages. The extension of calcified deposits then stopped. Finally, there was a fragmentation of the mineralized area which was progressively surrounded by uncalcified collagen fibrils. A demineralization process, caused by cells such as macrophages and multinucleated giant cells, rather than a resorption of the calcified deposits, was noted. It is important to emphasize that, in both models of ectopic calcification, an evolution toward ectopic ossification was never observed, which is perhaps due to the absence of extensive resorption mechanisms.
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    The fine structure of sublingual gland acinar cells of the Mongolian gerbil, Meriones unguiculatus, processed by rapid freezing followed by freeze-substitution fixation (1987)
    Springer
    Cell & tissue research 250 (1987), S. 305-314 
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    ISSN: 1432-0878
    Keywords: Sublingual gland ; Ultrastructure ; Golgi apparatus ; Rapid-freezing ; Freeze-substitution ; Gerbil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We compare the ultrastructure of the gerbil sublingual gland as seen after cryofixation followed by substitution with osmium tetroxide, with the more familiar appearance of material processed by glutaraldehyde-osmium chemical fixation. After primary cryofixation of fresh salivary glands, the nuclei of the mucous cells are found to be spherical in shape and, rather than being displaced toward the cell base, occupy a nearly central position in the cytoplasm, even in the storage phase of the secretory cycle. The mucous secretory granules are seen as membrane-limited inclusions, only rarely partially fused to each other. In both mucous and serous cells the Golgi cisterns have numerous large fenestrae which are aligned to form cytoplasmic channels which extend across the stack.
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    Ultrastructural changes in the fat body of adult female Aedes aegypti in relationship to vitellogenin synthesis (1978)
    Springer
    Cell & tissue research 186 (1978), S. 499-506 
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    ISSN: 1432-0878
    Keywords: Fat body ; Aedes aegypti ; Vitellogenin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the fat body of Aedes aegypti was followed from emergence through a blood meal. Changes in the volume of protein granules and lipid droplets were also examined. The relationship of these events to the known endocrinology of vitellogenin synthesis in mosquitoes is discussed.
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    URL: http://dx.doi.org/10.1007/BF00224938
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    Leptomeric fibrils and T-tubule desmosomes in the Z-band region of the mouse heart papillary muscle (1978)
    Springer
    Cell & tissue research 188 (1978), S. 205-215 
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    ISSN: 1432-0878
    Keywords: Myocardium ; Mouse ; Ultrastructure ; Leptofibrils ; Desmosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The papillary muscle of the heart of adult white mice is investigated. Intrafibrillarly located leptomeric fibrils, frequently encountered in the Z-band region of the myofibrils. The leptomeric fibrils are always running in a transverse direction and often in close proximity to the transverse tubules (which are also located at this level). There seems to be a close connection between the dense striae of the leptofibrils and the Z-bands of ordinary myofibrils. The leptomeric fibrils are spindle-shaped and have a length varying between 0.6 and 1.2 μm. The banding periodicity of the fibrils is approximately 0.16 μm. Occasionally desmosomes are observed in the T-tubule system.
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    URL: http://dx.doi.org/10.1007/BF00222631
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    Demonstration of rod and cone photoreceptors in the lamprey retina by freeze-replication and immunofluorescence (1987)
    Springer
    Cell & tissue research 249 (1987), S. 241-246 
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    ISSN: 1432-0878
    Keywords: Retina ; Photoreceptor cells ; Freeze-fracturing ; Ultrastructure ; Immunocytochemistry ; Lampetra japonica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In common with other cyclostomata, the Japanese river lamprey (Lampetra japonica) has a retina consisting of distinct types of photoreceptor cells called long and short photoreceptor cells. After freeze-fracture, disc membranes of these photoreceptor cells were characterized in common by a homogeneous distribution of intramembrane particles on the protoplasmic fracture faces, in contrast to those of the myeloid bodies bearing scattering particles. Immunofluorescent examination was applied to the retina with monoclonal antibodies raised against bovine and chicken rhodopsins. Positive immunoreactivity was found to be limited to outer segments of the short cell, leaving the entire body of the long cell and all other components of the retina negative. The results suggest that the short cell is more closely related to a rod-type photoreceptor cell characterized by rhodopsin as its visual pigment.
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    The ultrastructure of the tentacles of eleven species of dendrochirote holothurians studied with special reference to the surface coats and papillae (1987)
    Springer
    Cell & tissue research 248 (1987), S. 187-199 
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    ISSN: 1432-0878
    Keywords: Tentacles ; Ultrastructure ; Adhesion ; Echinodermata ; Dendrochirodita (11 species)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The tentacles of eleven species of dendrochirote holothurians have been studied. The water vascular system, deep fibre system, ectoneural nerve ring and superficial fibre system are described and are similar to those of other holothurian tentacles. A conspicuous fuzzy coat covers the entire tentacular surface except for the tips of cilia. On the basis of its structure it is thought to be an attenuated glycocalyx. Its function is discussed in relation to anti-fouling and surface adhesion. The two surface coats underlying the fuzzy coat are termed the cuticle. Bacteria are found both within the surface coats and in the sub-cuticular space. Primary fixatives lacking osmium give poor preservation of the surface coats. The adhesive papillae of the apices of the tentacles contain elements of support cells and two other cells named Type-1 and Type-2 papillar cells. The secretions of Type-1 papillar cells are dense-cored vesicles and may contain a proteinaceous adhesive. The vesicles fuse with the cuticle and release their products which are apparently disseminated along the fuzzy coat filaments. The secretions of Type-2 papillar cells may have a neurosecretory function. The different models of food capture by dendrochirote tentacles are discussed as are duo-glandular adhesive systems in relation to dendrochirote tentacles.
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    Comparative ultrastructure of the zona radiata from eggs of six species of salmonids (1987)
    Springer
    Cell & tissue research 250 (1987), S. 513-519 
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    ISSN: 1432-0878
    Keywords: Oocytes ; Structural patterns ; Pore canals ; Ultrastructure ; Salmonids ; Onchorhynchus tshawytscha, O. kisutch, O. gorbuscha, Salmo trutta, S. gairdneri, Salvelinus namaycush
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The zona radiata from unactivated and activated eggs from chinook salmon (Oncorhynchus tshawytscha), chum salmon (O. kisutch), pink salmon (O. gorbuscha), brown trout (Salmo trutta), rainbow trout (S. gairdneri) and lake trout (Salvelinus namaycush) were examined using scanning and transmission microscopy. The zona radiata in all species examined consisted of an outer adhesive coating, a thin densely staining zona radiata externa with pore canal plugs and a thick, fibrous zona radiata interna with a fibrous network on the inner surface. There was a two layer adhesive coating over the zona radiata externa in all species except pink salmon in which only one layer was observed. There were structural differences among species in the adhesive layer, zona radiata externa and plugs in the pore-canal openings.
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    Ultrastructure of endopolyploid antipodals inAconitum vulparia Rchb. (1987)
    Springer
    Protoplasma 140 (1987), S. 13-21 
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    ISSN: 1615-6102
    Keywords: Aconitum vulparia ; Endopolyploid antipodals ; Giant mitochondria ; Rough endoplasmic reticulum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of antipodals ofAconitum vulparia Rchb. was studied at two stages of development: at the earlier stage the endosperm has several nuclei, at the later one the endosperm is multinucleate. Over the investigated period the antipodal size enlarges distinctly. The wall ingrowths increase in size and number. Finally, they occur throughout the antipodal walls except for a small area in the extreme chalazal part, sunk deep into the nucellar podium. There are no plasmodesmata in the antipodal cell walls. The cytoplasm is dense and rich in ribosomes; it shows weak vacuolation. The rough endoplasmic reticulum is well developed. At the later stage dilated cisternae of endoplasmic reticulum are formed. Mitochondria, plastids and active dictyosomes are abundant. At the later stage some giant mitochondria are present; their matrix contains a large clear area with fine fibrils and an aggregation of fibrillar material. At this stage of development plastids have two types of inclusions: electron-transparent vacuoles and aggregations of electron-dense granules. The giant endopolyploid nuclei are considerably larger than those at the mature embryo sac stage; they are lobed on all sides. During the studied periodA. vulparia antipodals seem to be at their most active state.
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    Do intrathylakoidal inclusions really contain RuBPCase? (1987)
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    Protoplasma 140 (1987), S. 187-189 
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    ISSN: 1615-6102
    Keywords: Chloroplast ; Inclusion ; Ribulose 1,5-bisphosphate carboxylase/oxygenase ; Spinach ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Rapid-freezing and substitution-fixation method revealed more detailedin situ ultrastructure of spinach intrathylakoidal inclusions, which cannot be recognized by anti-RuBPCase large subunit immunocytochemically. This supports the possibility that the intrathylakoidal crystalline inclusion is not RuPCase but some other molecule normally synthesized within the lumen.
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    Physiological properties and cytological features of protoplasts prepared fromChlorella saccharophila (1987)
    Springer
    Protoplasma 139 (1987), S. 153-159 
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    ISSN: 1615-6102
    Keywords: Chlorella ; Protoplasts ; Photosynthesis ; Osmotic properties ; Nonosmotic volume ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Protoplasts were prepared from cells ofChlorella saccharophila by treatment with a mixture of pectinase and cellulase. The yield of protoplasts is dependent upon the culture conditions prior to cell wall digestion. In thin section chemically-fixed protoplasts were without wall remnants at the surface of the plasma membrane. Of particular interest is the relationship between the Golgi apparatus and a nuclear envelope-endoplasmic reticulum continuum. Protoplasts have a photosynthetic capacity lying between 70 and 80% of that of normal cells, but show the same response towards CO2 concentration and DCMU inhibition. Protoplasts also respond to changes in the osmolarity of the surrounding medium in accordance with the Boylevan't Hoff equation as if they are an osmometer. The nonosmotic volume (NOV) was calculated.
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    Ultrastructure ofCatharanthus roseus cells culturedin vitro and exposed to conditions for alkaloid accumulation (1987)
    Springer
    Protoplasma 140 (1987), S. 157-163 
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    ISSN: 1615-6102
    Keywords: Alkaloid production ; Catharanthus roseus ; Plant cell culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Periwinkle (Catharanthus roseus) cells cultured in 1-B 5 medium display the ultrastructure of parenchyma cells. The parenchyma character remained unchanged when cells were exposed to any one of three different conditions effecting alkaloid accumulation. Transfer of cells to “alkaloid production medium” for 2 weeks (condition 1) accorded two special features,i.e., unusually big lipid droplets in the cytoplasm and, upon fixation, one or several electron-dense droplets of spongy precipitate in vacuoles. Among hormone-autotrophic cultures (condition 2) some cells showed a fine electron-dense vacuolar precipitate. Addition ofPhythium homogenate (fungal elicitor) to cells cultured in 1-B 5-medium for 10 days (condition 3), cells showed a frequent appearance of singular big lipid droplets in the cytoplasm, whereas vacuoles remained devoid of precipitate. The appearance of big lipid droplets and of vacuolar precipitate is interpreted as progressing cytodifferentiation, but is coincidental with alkaloid accumulation.
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    Alisma embryogenesis: The development and ultrastructure of the suspensor (1987)
    Springer
    Protoplasma 137 (1987), S. 71-83 
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    ISSN: 1615-6102
    Keywords: Alisma ; Embryogenesis ; Endopolyploidy ; Suspensor differentiation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of the suspensor (consisting of a basal cell and a few chalazal cells) inAlisma plantagoaquatica andA. lanceolatum was investigated using cytochemical methods, light and electron microscopy. The basal cell becomes differentiated during the first three days of embryo development. As a result of endopolyploidization the volume of the nucleus rapidly increases, as does the quantity of chromatin it contains and the size of the nucleolus. As basal cell grows, its cytoplasm increases in volume and the number of organelles increase, and wall ingrowths begin to form on the walls at the micropylar pole of the cell. The full development and functioning of the suspensor occurs during the next three days. The enormous basal cell then attains its maximum degree of differentiation: its nucleus reaches a ploidy of 256n or 512n, the micropylar transfer wall is fully developed, as is the cytoplasm, rich in proteins, ribonucleic acids (RNA) and organelles, particularly dictyosomes and long cisternae of the rough endoplasmic reticulum. The chalazal suspensor cells joining the embryo proper to the basal cell also become differentiated. In the seven-day embryo the suspensor begins to degenerate which coincides with the cellularization of the endosperm at the micropylar pole of the embryo sac. The senescence of the suspensor involves the degradation of the nucleus, increasing cytoplasmic vacuolization, and a distinct decrease in protein and RNA content, first in the basal cell, then in the chalazal suspensor cells. Analysis of the development and ultrastructure of the basal suspensor cell suggests that it plays the role of an active metabolic transfer cell, translocating nutrients from the maternal tissues via the chalazal suspensor cells to the growing embryo proper.
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    An ultrastructural study of the viscin tissue ofPhthirusa pyrifolia (H.B.K.) Eichler (Loranthaceae) (1987)
    Springer
    Protoplasma 137 (1987), S. 145-155 
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    ISSN: 1615-6102
    Keywords: Mistletoe fruit ; Phthirusa pyrifolia ; Ultrastructure ; Development ; Viscin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The viscin tissue ofPhthirusa pyrifolia consists at maturity of two different cell types. The first of these (viscin cells) are greatly elongated and have massive secondary walls, the microfibrils of which are arranged strictly transversely, and are soaked with mucilaginous noncellulosic polysaccharides. The second type of cells (vesicular cells) is much broader, with a very extensive vacuolar system and thin primary cell walls only. Viscin cells are capable of being stretched very greatly, the microfibrils of the secondary wall then becoming oriented more or less longitudinally. In nature, this corresponds to the time of attachement to the host surface, and is followed by drying and, possibly, shortening of the viscin cells. Developmental study of the tissue suggests that Golgi bodies are the major organelles participating in polysaccharide production. The actual mucilage seems to originate from three sources: an unorganized substance which accumulates between the plasmalemma and compound middle lamella; spherical vacuoles which seem to be embedded in the central vacuole, some of which are seen open to the outside of the cell; and from the dissolution at maturity of the compound middle lamella. It is suggested that the two types of cells may correspond to the two major functions of viscin, viz., host attachment (viscin cells) and nutrition of the disseminator (vesicular cells).
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    Sugar secretion from the nectary ofStrelitzia: an ultrastructural and physiological study (1987)
    Springer
    Protoplasma 137 (1987), S. 168-182 
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    ISSN: 1615-6102
    Keywords: Nectary ; Secretion rates ; Strelitzia ; Sugar fluxes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Flowers ofStrelitzia reginae grown at a constant 20°C have been shown to secrete nectar at a rate of up to 5.0 mg (d.w.) sugar h−1 (mean rate 1.2±0.1 mg h−1) for up to seven days. The nectar has a total concentration of about 25% during the early part of the secretory period but often falling to less than 10% towards the end of secretion. Each flower has three septal nectaries, the cuticle-lined ducts of which open into a nectar basin formed by the fused bases of two petals on the top of the receptacle. The layer of epithelial cells which secretes the sugars is thrown into highly convoluted folds and the distal parts of these cells have profuse wall inpushings. Both of these modifications have the effect of increasing the surface area of the plasmalemma apparently available for unloading the nectar. The glandular epithelium of the three, 26 mm long, nectaries of a single flower would be lined by more than 17×106 cells with a total plasmalemma surface area for unloading of at least 2,000 mm2. There is little evidence to suggest that secretion is a granulocrine process inStrelitzia. While there is abundant, stacked endoplasmic reticulum, and numerous vesicles containing fibrillar material, these do not appear to be directly concerned with sugar secretion. Data from specific flowers suggest that transmembrane fluxes in the range of 1.0×106 to 1.0×10−7 mol s−1 m−2 would be necessary to sustain the observed rates of secretion. While these are relatively high, when taken together with the structural information, they lead to the conclusion that secretion inStrelitzia is probably an eccrine process.
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    Ultrastructural study ofErwinia amylovora strains: Effect of culture conditions and fixation procedures (1987)
    Springer
    Protoplasma 139 (1987), S. 1-8 
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    ISSN: 1615-6102
    Keywords: Ultrastructure ; Erwinia amylovora ; Outer membrane ; Fixation procedure ; Cold storage ; Virulence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Modifications of the ultrastructure of the plant pathogenic bacteriumErwinia amylovora were analyzed according to growth conditions and fixation procedures. Six bacterial strains with various virulence characteristics were examined. Cultures were grown either in Yeast Peptone Glucose medium (YPG) or in a medium containing asparagine (ASP) supplemented with sorbitol (1% or 5% sorbitol). When grown in ASP + 1% sorbitol or in YPG, the strains, structurally similar to each other in ASP + 5% sorbitol, presented different frequencies of small evaginations which were observed arising from the cell surface mainly after an OsO4 fixation step. There was no correlation between the frequency of evaginations and the virulence of the strain. An overnight storage at 4 °C considerably enhanced the frequency of the evaginations. It was suggested that the OsO4 fixation step visualized differences in the bacterial outer membrane structure.
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    Changes in carbohydrates and ultrastructure in xylem ray cells ofPopulus in response to chilling (1987)
    Springer
    Protoplasma 137 (1987), S. 45-55 
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    ISSN: 1615-6102
    Keywords: Carbohydrates ; Chilling effects ; Populus ; Sugars ; Ultrastructure ; Xylem ray cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of xylem ray cells inPopulus was studied in conjunction with their content of individual sugars and of starch. They differ considerably in structure and in carbohydrate content at the three chosen stages,i.e., of starch deposition (August), of starch maximum (November), and of starch dissolution (January). The transition from the summer to winter stage was also induced experimentally by storage of tissue at 0°C. Both in nature and after cold-storage, sucrose and its galactosides raffinose and stachyose were accumulated to a great extent, contributing up to 69.7 and 57.3% of total sugar content, respectively. They originated parallel to the breakdown of starch and to the appearance of abundant vesicular and dilated ER cisternae. Results indicating that they are the specific sites of sucrose accumulation, and/or its galactosides, are discussed. The occurrence of phytoferritin-like crystalloids in amyloplasts and of vacuolar flocculent material, which condenses into electron-dense bodies of suspectedly proteinaceous nature, is described.
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    Reproduction inTriticale (1987)
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    Protoplasma 139 (1987), S. 100-104 
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    ISSN: 1615-6102
    Keywords: Triticale ; Ultrastructure ; Fertilization ; Karyogamy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Karyogamy during fertilization inTriticale starts about 60 minutes after pollination. It was studied in the egg and the central cell by electron microscopy. The fusion of the sperm cell nuclei with the egg and central cell nuclei begins with nuclear envelope fusion presumably with participation of the endoplasmic reticulum cisternae. Initially, fusion is restricted to small bridges between the nuclei. It is accompanied by the appearance of intracisternal lipid droplets.
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    A light and electron microscope study ofPicea glauca (White spruce) somatic embryos (1987)
    Springer
    Protoplasma 140 (1987), S. 100-109 
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    ISSN: 1615-6102
    Keywords: Actin ; Conifer ; Electron microscopy ; Picea glauca ; Somatic embryo ; Tissue culture ; Ultrastructure ; White spruce
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Somatic embryos in embryogenic callus cultures derived from Immature zygotic embryos ofPicea glauca (White spruce) were examined by light and electron microscopy. Somatic embryos consist of an embryonic region of small densely cytoplasmic cells subtended by a suspensor consisting of long highly vacuolated cells. Mitotic figures are frequent in the embryonic cells but are not observed in the suspensor. Cell divisions in the embryonic region apparently produce rows of cells which elongate to form the suspensor. The presence of abundant polysomes, coated membranes and dictyosomes in the cytoplasm of embryonic and upper suspensor cells suggests rapid growth of the embryo. In contrast the basipetal suspensor cells appear to be senescing. While only a few scattered microfilaments are present in the meristematic cells, the upper suspensor cells contain numerous bundles of longitudinally oriented microfilaments. These bundles correspond to actin cables observed in light microscope preparations stained with rhodamine labelled phalloidin and are oriented parallel to the direction of active streaming in these cells.
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    Development of the filiform hairs on the cerci of Gryllus bimaculatus Deg. (Saltatoria, Gryllidae) (1978)
    Springer
    Cell & tissue research 187 (1978), S. 1-24 
    Details
    ISSN: 1432-0878
    Keywords: Insect sensillum ; Mechanoreceptor ; Development ; Ultrastructure ; Gryllus bimaculatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The filiform hairs, mechanoreceptors of Gryllus, pass through six developmental stages during the last larval stage. The cytoplasm of their sense cells suggests intensive synthesis of protein for cellular metabolism and intercytoplasmic exchange of material via glial evaginations. Ultrahistochemical tests demonstrated acid phosphatase in the lysosomes as well as in components of the Golgi apparatus. There was no significant change in the appearance of the sense cell cytoplasm, indicating a maintained functional state also during molting. The new cuticular apparatus is formed after apolysis by the three enveloping cells. Formation of the replacement hairs is initiated by a cytoplasmic outgrowth of the trichogen cell. During morphogenesis of the new hair, the microtubules serve as a cytoskeleton and probably control the flow of vesicles, which contain phenol oxidase, also demonstrated in the Golgi apparatus, and are incorporated into the new cuticle. Bundles of microfibrils are involved in the surface sculpturing of the replacement hair. The trichogen cell also forms a number of structural elements, e.g. the “cup” and “strut” marked geometric peculiarities of which indicate that they are important in the spatial orientation of the dendrite and thus also in transduction. Reduction of the apical cell membrane of the tormogen cell after apolysis permits unrestricted growth of the new hair into the exuvial space. The tormogen cell participates in the formation of the joint membrane, parts of the socket and the articulation of the hair.
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    URL: http://dx.doi.org/10.1007/BF00220615
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    Early effects of prolactin on lactating rabbit mammary gland (1978)
    Springer
    Cell & tissue research 187 (1978), S. 25-43 
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    ISSN: 1432-0878
    Keywords: Lactation ; Prolactin ; Secretion ; Caseins ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Les effets de la prolactine, sur la sécrétion des protéines du lait, ont été étudiés grâce à des incubations de tranches de glandes mammaires de lapines en lactation. Dès 15min après l'addition de l'hormone au milieu d'incubation, la morphologie de la cellule est modifiée: le volume relatif des vésicules et des saccules Golgiens est fortement augmenté. Lorsque la prolactine est rajoutée, immédiatement après un marquage en 〈pulse〉 des protéines (pendant 3 min par la L-leucine 3H), elle provoque, en une heure, une augmentation de la sérétion des caséines radioactives dans le milieu d'incubation. Cette augmentation de la quantité de caséines sécrétées ne provient ni d'une augmentation du transit intracellulaire des protéines néosynthétisées (étudié par autoradiographie en Microscopie Electronique), ni d'une augmentation d'incorporation des acides aminés (mesurée par l'incorporation d'acides aminés non métabolisables), ni d'une augmentation de la synthèse protéique totale, dans le délai d'une heure. Les relations possibles entre l'action de la prolactine sur l'aspect morphologique d'un organite cellulaire tel que l'appareil de Golgi et sur la sécrétion des caséines sont discutées.
    Notes: Summary Effects of prolactin on the secretion of milk proteins have been investigated by incubating mammary tissue fragments from lactating rabbits. Within 15min of adding the hormone to the incubation medium, cell morphology is modified: the relative volume occupied by the Golgi region is greatly increased. When prolactin is added immediately after a pulse labelling of proteins (3 min with 3H-L-leucine), the amount of labelled caseins secreted during one hour is significantly increased. This increase proceeds neither from an acceleration of intracellular transit of caseins (as shown by electron microscopic autoradiography) nor by an enhancement of amino acid uptake (as measured by incorporation of non-metabolizable amino acids) nor by an increase of overall protein synthesis, during the first hour. The action of prolactin on the morphology of such subcellular organelles as the Golgi apparatus and its influence on casein secretion are discussed.
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    Cytological observations on the blood and hemopoietic tissue in the crab, Callinectes sapidus (1978)
    Springer
    Cell & tissue research 187 (1978), S. 79-96 
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    ISSN: 1432-0878
    Keywords: Crustacean hemocytes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A fine structural analysis of hemocytes recovered from the pericardial sinus of the blue crab (Callinectes sapidus) demonstrates that hyaline cells, intermediate cells, and granuloyctes are present in the hemolymph. A detailed consideration of their shared and differing cytological features suggests that the various blood cells represent different stages of cytogenesis along a common or single path of cellular differentiation. The potential functional complexity of the hemocytes is attested to by the occurrence within their cytoplasm of three and/or possibly four morphologically distinct types of inclusion bodies, and other membrane-bounded compartments (e.g., lysosome-like structures, autophagic vacuoles, peroxisome-like bodies) whose function is unknown. Preliminary examination of the well-developed Golgi organelle in the intermediate cells and granulocytes indicates its probable participation in the elaboration of the inclusion bodies; however, the details of its role in granulogenesis and in the known plurifunctional capacities of these cells remain obscure.
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    Unusual mitochondrial ultrastructure in the pig adrenal cortex (1978)
    Springer
    Cell & tissue research 187 (1978), S. 129-134 
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    ISSN: 1432-0878
    Keywords: Adrenal cortex (Pig) ; Mitochondria ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Unusually large mitochondria with few cristae were observed in the cells of the boundary layer between the zonae fasciculata and reticularis of the pig adrenal. These mitochondria occasionally contained parallel arrays of beaded filaments which appeared to be composed of repetitive electron opaque particles, measuring 10 to 11 nm in diameter. The possibility that these filaments are arranged in closely packed arrays of tubular structures with a central filament is discussed.
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    URL: http://dx.doi.org/10.1007/BF00220624
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    Studies on the midgut of Centropages typicus (Copepod, Calanoid) (1978)
    Springer
    Cell & tissue research 187 (1978), S. 333-353 
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    ISSN: 1432-0878
    Keywords: Midgut ; Centropages typicus (Copepod, Calanoid) ; Structure ; Ultrastructure ; Digestive function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary From a structural study of the midgut of Centropages typicus, three main zones presenting different cellular associations may be defined. The ultrastructural study carried out allows us to distinguish several cell types. The four principal cell categories (E, R, F and B) show a more or less marked resemblance with those identified in the Malacostraceans, especially in the hepatopancreas of Decapods. The three types R, F and B, which are subdivided according to their localization (R and R′) or their developing stages (F1, F2; B1 to B5), are recognized by the following characteristics: R-cells with smooth endoplasmic reticulum and high microvilli (zones I and III); F-cells with rough endoplasmic reticulum and short or spherical microvilli (zones I and II); B-cells with a large vacuolar apparatus made up of lysosome-like dense bodies associated with vacuoles originating from pinocytosis (zone II). From the comparisons of morphological, ultrastructural and histochemical results concerning Centropages typicus with author's data, we propose and discuss these functions for the three principal cell types: synthesis and secretion of pre-digestive enzymes (F1 and F2-cells); enzyme synthesis, intracellular digestion and extrusion (B1 to B5-cells); absorption (R and R′-cells).
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    Morphological changes in the ultrastructure of the thyroid epithelium of Notophthalmus viridescens after hypophysectomy and TSH- and prolactin stimulation (1978)
    Springer
    Cell & tissue research 187 (1978), S. 305-313 
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    ISSN: 1432-0878
    Keywords: Thyroid ; Ultrastructure ; Hypophysectomy ; TSH- and prolactin treatment ; Notophthalmus viridescens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the newt, Notophthalmus viridescens, hypophysectomy results in progressive atrophy of the thyroid cells to the point of irreversible degeneration. After exclusive TSH-stimulation of hypophysectomized newts, increased endocytotic activity of the follicular epithelium is observed. Prolactin stimulation under the same conditions prevents atrophy but does not result in increased cell activity, as expressed by the reduced amount of microvilli and the lack of endocytotic activity. Combined TSH- and prolactin stimulation also results in cell activation, but the activation level of exclusively TSH-stimulated cells is not reached. Although prolactin prevents cellular atrophy and degeneration of the follicular epithelium, it reduces the TSH-induced activation of the thyroid epithelium.
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    Ultrastructure of differentiating hemocytes in the embryo of Oncopeltus fasciatus Dallas (Insecta, Heteroptera) (1978)
    Springer
    Cell & tissue research 187 (1978), S. 479-488 
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    ISSN: 1432-0878
    Keywords: Embryonic hemocytes ; Insecta ; Oncopeltus fasciatus ; Differentiation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The hemocytes of Oncopeltus differentiate rather early during embryogenesis. They are segregated by the mesoderm soon after its formation (about 50h after egg deposition). Newly segregated hemocytes show the “typical” features of “embryonic” cells: many free ribosomes, a few strands of rough ER, the cisternae of which are considerably distended, electron lucent vacuoles around the periphery, and glycogen deposits. A few hours thereafter the hemocytes undergo striking subcellular changes. First, glycogen, electron lucent vacuoles and rough ER disappear and phagocytotic activity can be observed. Golgi complexes become well expressed and give rise to electron dense vesicles which fuse to larger bodies. Then, rough ER develops again and occupies large areas of the cytoplasm. Its cisternae are often considerably distended by proteinaceous secretions. All hemocytes undergo the same steps of differentiation. Embryonic hemocytes obviously play a decisive role in the elimination of waste products, in particular of tissue debris that results from programmed cellular death. The significance of the conspicuous protein secretions is not fully understood. They may participate in the deposition of the acellular connective tissue, or may have some of the other functions ascribed to insect blood cells. Larvae and imagines of Oncopeltus have four types of hemocytes, which agree rather well with those found in Rhodnius (Lai-Fook, 1970). All embryonic hemocytes, aside from the newly segregated ones, represent plasmatocytes but, unlike plasmatocytes of postembryonic stages, they contain no large inclusion bodies. Newly segregated embryonic hemocytes, in addition to their “typical embryonic” features, have some similarities with larval and adult prohemocytes. Oenocytoids and granulocytophagous cells are absent in the embryo. Some aspects concerning the differentiation and classification of hemocytes are discussed.
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    The paramedial neurosecretory cells of the suboesophageal ganglion in the cricket, Teleogryllus commodus (Walk.) (1978)
    Springer
    Cell & tissue research 187 (1978), S. 495-506 
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    ISSN: 1432-0878
    Keywords: Suboesophageal ganglion (cricket) ; Paramedial neurosecretory cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The paramedian neurosecretory cells (PNC) (A-type) in the suboesophageal ganglion of the cricket, Teleogryllus commodus (Walk.), have been studied by electron microscopy. In control animals (10 day-old virgin females) three different cell stages could be distinguished: Stage 1 shows a variable content of elementary granules and characteristics of actively synthesising cells. Stage 2 is characterised by the presence of numerous fusion bodies, which are formed by the coalescence of elementary granules, presumably for storage purposes. In stage 3 granules are degraded in lysosomes (?). While the production of material rich in cysteine increases after ovariectomy (Dürnberger et al., 1978), the fine structure of the cells is essentially unchanged. The only noted differences are an increased lysosomal synthetic activity and the existence of stages intermediate between 2 and 3, which were never found in control animals. The functional significance of the different stages is discussed.
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    Influence of gonadotropic hormones on the ultrastructure of rat pinealocytes (1978)
    Springer
    Cell & tissue research 188 (1978), S. 133-141 
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    ISSN: 1432-0878
    Keywords: Pineal organ, rat ; Ultrastructure ; Gonadotropic hormones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The influence of gonadotropic hormones on the ultrastructure of rat pinealocytes was studied. Human chorionic gonadotropin (HCG) as well as pregnant mare serum gonadotropin (PMSG) caused a marked activation of pinealocytes. It is characterised by a conspicuous proliferation of the granular endoplasmic reticulum and Golgi apparatus as well as an increase in number of dense core vesicles, mitochondria, dense bodies, subsurface cisternae and vesicles in the terminal buds of pinealocyte processes. The changes after HCG administration were more pronounced than after PMSG.
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    URL: http://dx.doi.org/10.1007/BF00220520
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    Changes in the adrenal cortex of the rat after chronic administration of the steroidogenic inhibitor U-8113 (1978)
    Springer
    Cell & tissue research 190 (1978), S. 123-134 
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    ISSN: 1432-0878
    Keywords: Adrenal ; Steroidogenesis ; Inihibitor ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In concert with studies of the effects of various pharmacologic inhibitors of corticosteroidogenesis on adrenocortical morphology, U-8113, an analog of amphenone B, was administered daily to Sprague-Dawley rats for 7, 14, 21 or 30 days. The primary morphological responses involved increases in adrenal weight, width of zona fasciculata, width of zona reticularis, intracellular lipids, mitochondrial size, mitochondrial vacuolation and crystalline-like inclusions, small coated vesicles, lysosomes, autophagic vacuoles and cholesterol ester clefts. In particular, the increases in lysosomes, coated vesicles and autophagic vacuoles containing morphologically altered mitochondria were considered reflective of mechanisms designed to maintain cellular integrity amidst functional impairment. Lipid analysis revealed marked increases in cholesterol esters and phospholipids, supportive of morphological observations. When permitted a 14 day recovery period following either 14 or 30 days of inhibitor therapy, most fine structural alterations and lipid derangements were diminished, and the cells approximated normal parameters.
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    The respiratory epithelium in the lungs of the slow-worm, Anguis fragilis (1978)
    Springer
    Cell & tissue research 190 (1978), S. 337-347 
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    ISSN: 1432-0878
    Keywords: Respiratory epithelium ; Anguis fragilis ; Pneumonocytes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithelium covering the respiratory portion in the lung of the slow-worm (Anguis fragilis) has been studied by electron microscopy. The epithelium is composed of two different types of pneumonocytes. The type I pneumonocytes are roughly squamous and their cytoplasmic sheets spread over relatively large areas of the septal walls. These cytoplasmic sheets are attenuated in regions where they overlie septal capillaries; they usually have extensive areas of contact with adjacent cells. The type II pneumonocytes are also squamous but are more compact and possess more organelles. Their osmiophilic inclusion bodies are especially conspicuous. Most of their microvilli are concentrated on the surfaces of cytoplasmic “hillocks”. Deposits of membranous material are present in the air sacs. The morphological evidence suggests that the type II cells of Anguis secrete surface-active material.
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    An ultrastructural study of regeneration of minced smooth muscle in the vas deferens of the guinea-pig (1978)
    Springer
    Cell & tissue research 190 (1978), S. 481-493 
    Details
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Regeneration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopic studies were made of the regeneration of minced smooth muscle of the vas deferens of the guinea-pig 3 days to 15 weeks after operation. At 3–5 days the mince contained degenerating smooth muscle cells and dedifferentiating cells showing characteristics of embryonic smooth muscle cells: numerous free ribosomes, well developed rough endoplasmic reticulum and Golgi apparatus with few peripherally placed myofilaments associated with dense bodies. During the first two weeks of regeneration, scattered cells surrounded by debris and collagen were separated by a large extra-cellular space. After three weeks, extracellular space was reduced to near normal values. Regenerating cells had a shorter length than normal cells, but during later stages of regeneration they showed an increase in diameter. Muscle effector bundles began to form after 2 to 3 weeks. Initially there were large gaps between the muscle cells, but at later stages of bundle formation, the extracellular space between the muscle cells was much reduced. From 3 weeks, arterioles appeared between the smooth muscle bundles in the regenerating areas. Regeneration of individual smooth muscle cells was complete by 15 weeks after the operation.
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    The ultrastructure of pinealocytes in the golden mole (Amblysomus hottentotus) with special reference to the granular vesicles (1978)
    Springer
    Cell & tissue research 191 (1978), S. 39-56 
    Details
    ISSN: 1432-0878
    Keywords: Pinealocytes ; Golden mole ; Secretory process ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Les pinéalocytes de la glande pinéale de la Taupe dorée Amblysomus hottentotus (Mammifère aveugle et vivant toujours dans une obscurité complète) examinés au microscope électronique ont été comparés à ceux d'autres Mammifères. Une seule population de pinealocytes a été observée. Mitochondries, ribosomes, réticulum endoplasmic granulaire, inclusions lipidiques et rares structures lysosomiales sont présents dans le périkaryon. De nombreux grains de glycogène formant le plus souvent de typiques “accumulations” ont été fréquemment observés associés à des vacuoles. Un grand nombre de vésicules granulaires est la caractéristique première des pinéalocytes. Un phénomène d'excrétion, caractérisé par une dissolution in situ du coeur dense, a été observé. L'importance physiologique de ces vésicules granulaires est discuté.
    Notes: Summary The ultrastructure of the pinealocytes of the golden mole (Amblysomus hottentotus), a blind subterranean mammal living in complete darkness, was examined and compared with that of pinealocytes of other mammals. On the basis of the presence of granular vesicles and glycogen granules, only one population of pinealocytes was found. Large mitochondria, ribosomes, lipid inclusions and scarce lysosomes were observed in the perikaryon. Numerous glycogen granules, often forming typical accumulations, were frequently found to be associated with typical vacuoles. An extraordinary large number of granular vesicles is characteristic of the golden mole pinealocyte. Phenomena of excretion of compound(s) stored in the granular vesicles were identified. Morphologically this is characterized by dissociation of its granular core in situ while its limiting membrane is preserved. The physiological significance of the secretory process characterized by the formation of these granular vesicles is discussed.
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    The uterovaginal sperm host glands of the quail (Coturnix coturnix japonica) (1978)
    Springer
    Cell & tissue research 191 (1978), S. 101-114 
    Details
    ISSN: 1432-0878
    Keywords: Sperm host glands ; Quail (Coturnix coturnix jap.) ; Ultrastructure ; Ultracytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural and ultrahistochemical studies were performed on the uterovaginal sperm host glands of the quail (Coturnix coturnix japonica). The proximal parts of the glandular necks are lined by a pseudostratified epithelium, consisting of high columnar ciliated cells and small, irregular shaped, basal cells. The true glandular epithelium is composed only of columnar cells with microvilli on their luminal end. A characteristic luminal feature is a large lipid droplet in the perinuclear region. In the subplasmalemmal region numerous tubular profiles are seen which could represent a cellular resorption system. To evaluate the absorptive capacity of the Uterovaginal sperm host glands, tracer studies with HRP, ferritin, lanthanum and ruthenium red were undertaken. Since between 5 min and 3 h after injection no absorption could be found with the techniques mentioned, it is suggested that phagocytosis of spermatozoa by the glandular epithelium is not likely to occur.
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    The structure of the nervous system of the pluteus larva of Strongylocentrotus purpuratus (1978)
    Springer
    Cell & tissue research 191 (1978), S. 233-247 
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    ISSN: 1432-0878
    Keywords: Nervous system ; Pluteus ; Ultrastructure ; Echinoderms ; Strongylocentrotus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Tissues that have the ultrastructural characteristics of nervous tissues are associated with ciliary and muscular elements of the pluteus larva of Strongylocentrotus purpuratus. The nerve cells are found along the margins of the ciliary bands, which are composed predominantly of spindle-shaped ciliated cells. The nerve cells contribute axonal processes to a tract of axons, which runs at the base of the ciliary band throughout its length. Axonal tracts, in the esophagus, lie beneath the circumesophageal muscles. Branched microvilli, which have been interpreted as sensory receptors, are located on the oral side of the main ciliary band and connect with the nerve cells in the ciliary band. The nervous structures described here, and other tissues of the pluteus that have been previously described as nervous, are compared on the basis of their association with receptor and effector organs, and their ultrastructural characteristics.
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    The ultrastructure of multilamellar bodies and surfactant in the human lung (1978)
    Springer
    Cell & tissue research 193 (1978), S. 219-229 
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    ISSN: 1432-0878
    Keywords: Multilamellar bodies (human lung) ; Surfactant ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Normal tissues from human lungs were dehydrated through Epon 812 resin to retain many of the lipids and carbohydrates in thin section. The three-dimensional structure of the multilamellar body was determined. The paired layer of phospholipid heads (PH) is 36Å thick; the layer of fatty-acid tails (FA) is 31Å, the same as reported previously for non-human primates and rodents. The human multilamellar body is apparently unique: the lamellae of the major focus divide into two or three lamellae; the matrix material of the core is without vesicular bodies and a projection core is present. When compared with those of the rat, human tissues contain a greater number of lamellar foci and fewer lamellae per focus. The presence of a peripheral layer of lamellae, an ever-present external limiting membrane, and the fusion of multilamellar bodies are also characteristic. Tubular myelin surfactant has the same appearance as in other mammals. Multilamellar bodies were observed in direct communication with Golgi vesicles. Their origin from multivesicular bodies and their maturation through secretion and exocytosis were demonstrated. Untransformed multilamellar bodies in the alveolar space demonstrated three periodicities (P): (1) compact regular lamellae, PH = 36Å, FA = 31Å, P = 66Å; (2) compact broad lamellae, PH = 72Å, FA = 22Å, P = 94Å; (3) loose lamellae, PH = 36Å, FA = 36Å, FA = 31Å with a variable interlamellar space.
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    High resolution radioautographic study of newly formed protein in striated muscle with emphasis on red and white fibres (1978)
    Springer
    Cell & tissue research 193 (1978), S. 269-282 
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    ISSN: 1432-0878
    Keywords: Striated muscle ; Proteins ; Radioautography ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The elaboration and distribution of newly formed proteins in the striated muscle of 21-day-old mice were investigated by quantitative radioautography at intervals between 2 and 240 min after intravenous injection of tritiated leucine. In radioautographs, the localization and the relative label concentration were comparatively estimated for the different components of mitochondria-rich fibres, in particular of red fibres, from the tibialis anterior muscle and of mitochondria-poor fibres from the oesophageal muscle. As early as 2 min after injection, radioactivity was detected over the nucleus, the polysome-rich sarcoplasm, the A and I bands, the Z lines, and the mitochondria in the two fibre types. Label localization did not change with time. The relative label concentration increased similarly in the polysome-rich sarcoplasm and the A and I bands of both fibre types within 30 min after injection, a confirmation that biosynthesis of myofibrillar proteins takes place rapidly. In each case, concentration was higher in the Z lines than in the I bands, and higher in the I bands than in the A bands, thus showing “in vivo” that the rates of synthesis of sarcomere protein components are not uniform. However, the relative label concentration was found to be higher in the Z lines of mitochondria-poor fibres than of mitochondria-rich fibres: this suggests that a higher synthetic rate of Z line protein, and probably of α actinin, is characteristic of the first type. Inversely, the concentration was higher in the mitochondria of mitochondria-rich fibres. This lead to the belief that high rate of protein synthesis in these organelles may account for the high rate of label incorporation into this type of fibre.
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    Extravascular transfer within the anuran pars intermedia (1978)
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    Cell & tissue research 193 (1978), S. 297-313 
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    ISSN: 1432-0878
    Keywords: Pars intermedia ; Peroxidase ; Ultrastructure ; Extravascular space ; Stellate cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To study the transport of protein from the blood into and throughout the sparsely vascularized pars intermedia of anurans, the electrondense tracer, horseradish peroxidase (HRP) was injected into the vascular system of adult frogs. A strong reaction product was localized in small vesicles in the cytoplasm of that portion of the stellate cells immediately beneath the vascular spaces. Also, within two minutes after an injection of HRP, which was given during a period of one minute, the reaction product was seen in the extracellular spaces between the stellate and/or MSH secretory cells throughout the gland. Additionally, it appeared that HRP was pinocytosed by the stellate cell processes in the interior of the pars intermedia. Since frogs adapted to different backgrounds were perfused with HRP for a variety of time periods, from 3 to 90 min, it was thought that it would be possible to trace the pathway of the HRP-filled vesicles as they moved through the stellate cells. There did not appear to be a migration of these vesicles within the cells. Because of the electron density of the HRP, the tortuous extensions from the perivascular spaces of the capillary plexus intermedius were obvious as they ramified into the pars intermedia and pars nervosa. In the frogs not injected with HRP, it was possible to observe the substructure of these ramifications which paralleled the stellate cells and formed enlargements at the convergence of the stellate cell processes and sometimes the nerve processes. An extravascular, many-branched transport system that penetrates the parenchyma is discussed in addition to the possible transfer role of the stellate cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209042
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  • 94
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    Scanning electron microscope studies of the egg shell in some anostraca (Crustacea: Branchiopoda) (1978)
    Springer
    Cell & tissue research 193 (1978), S. 337-351 
    Details
    ISSN: 1432-0878
    Keywords: Egg shells ; Anostraca ; Alveolar meshwork ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The tertiary shell of the eggs of anostracan crustaceans consists of two layers, an outer cortex and an inner alveolar layer. Scanning electron microscope studies show that, in most species, these layers are separated by a subcortical space which intercommunicates with spaces in the cortex and with the meshwork of the alveolar layer. No evidence was found for direct communication between pores on the surface of Branchipus stagnalis eggs and the subcortical space. No surface pores were found in the eggs of Branchinecta packardi, Chirocephalus diaphanus, Anemia salina, nor in eggs of the notostracan Triops cancriformis. Similarities in structure and possible functions of the egg shells of anostracan crustaceans and certain insects are discussed in relation to similarities in certain features of their environments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209045
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  • 95
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    The pineal gland of the gerbil, Meriones unguiculatus (1978)
    Springer
    Cell & tissue research 193 (1978), S. 323-336 
    Details
    ISSN: 1432-0878
    Keywords: Pineal gland ; Gerbil ; Pinealocytes ; Concretions ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy was employed in a study of the pineal gland of the Mongolian gerbil (Meriones unguiculatus). It was determined that the gerbil pineal gland contains pinealocytes and glial cells with the pinealocytes being the predominant cell type. The pinealocytes contain numerous organelles traditionally considered as being either synthetic or secretory in function such as an extensive Golgi region, smooth (SER) and rough (RER) endoplasmic reticulum, secretory vesicles and microtubules. Other cytoplasmic components are also present in the pinealocytes (synaptic ribbons, subsurface cisternae) for which no function has been assigned. Dense-cored vesicles are rare. Vacuolated pinealocytes are present and appear to be intimately associated with the formation of the pineal concertions. Evidence presented supports the proposal that the concretions form within the vacuoles. Once the concretions reach an enlarged state, the vacuolated pinealocytes break down and the concretions are thus extruded into the extracellular space where they apparently continue to increase in size. The morphology of the glial cells was interpreted as indicative of a high synthetic activity. The glial cells contain predominantly the rough variety of endoplasmic reticulum and form an expansion around the wide perivascular area.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209044
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  • 96
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    Sarcotubular development in dystrophic skeletal muscle cells (1978)
    Springer
    Cell & tissue research 194 (1978), S. 125-130 
    Details
    ISSN: 1432-0878
    Keywords: Sarcotubular development ; Chick embryo ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Dilations of the sarcotubular system and misaligned myofilaments have been reported as early indicators of muscular dystrophy in skeletal muscle. Since the developing tubular component is believed instrumental in initial myofilament alignment during myogenesis, tubular development is evaluated using normal and dystrophic chick embryo skeletal muscle and cultures of normal and dystrophic embryonic pectoral muscle incubated in the presence of horse spleen ferritin. Comparisons of the findings show that periodic tubules are absent from dystrophic somitic muscle and that invaginating tubules from the sarcolemma are found in fewer, randomly located areas of dystrophic pectoral muscle cells. The results indicate that the tubular component is not involved in the bizarre vesiculations seen in mature dystrophic muscle, however, the malalignment of dystrophic myofilaments is probably the result of the poorer development of the T system in this muscle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209238
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  • 97
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    Distribution, ontogeny and ultrastructure of pancreatic polypeptide (PP) cells in the pancreas and gut of the chicken (1978)
    Springer
    Cell & tissue research 194 (1978), S. 377-386 
    Details
    ISSN: 1432-0878
    Keywords: Pancreas ; Gut ; Pancreatic polypeptide (PP) cells ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pancreatic polypeptide (PP) cells in the pancreas and gut of chickens were studied by immunocytochemistry. In the pancreas PP cells were numerous and disseminated in the exocrine parenchyma. In this location they were first seen at the 9th day of incubation, i.e. several days after the appearance of glucagon, insulin and somatostatin cells. Very large numbers of these cells occurred from about the 14th day until shortly after hatching when the PP cell frequency was somewhat reduced. At the 17th day of incubation PP cells appeared in the duodenum. Subsequently the number of PP cells in the duodenum increased, and PP cells began to appear also in the jejunum-ileum (19th day) and in the proventriculus and colon (21st day). At hatching and a few days thereafter, PP cells were relatively numerous in the small intestines but much less frequent in the proventriculus and colon. One week after hatching PP cells had disappeared from the colon but remained in the proventriculus and small intestines. Ultrastructurally the PP cell was clearly distinguishable from the insulin, glucagon and somatostatin cells. It was characterized by the presence of spherical cytoplasmic granules which were membrane-bound and moderately electron dense. Areas of firm adhesion between PP cells and acinar cells in the form of desmosomes and possibly also gap junctions were observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236159
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  • 98
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    Ultrastructural changes in the dermal chromatophore unit of Hyla arborea during color change (1978)
    Springer
    Cell & tissue research 194 (1978), S. 405-418 
    Details
    ISSN: 1432-0878
    Keywords: Hyla arborea ; Reflectance spectrophotometry ; Ultrastructure ; Color change ; Chromatophores
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die strukturellen Veränderungen der Chromatophoren beim Farbwechsel von Hyla arborea wurden mit Hilfe von Elektronenmikroskopie und Reflexions-Mikrospektrophotometrie untersucht. Während des Wechsels von einer hellgrünen zu einer dunkelgrünen Farbe breiten sich die Melanosomen aus, bis sie schließlich die Iridophoren und teilweise auch die Xanthophoren umhüllen; die becherförmigen Iridophoren werden zylinderoder kegelförmig. Gleichzeitig verändern die Purintäfelchen ihre Orientierung parallel zur Oberseite der Zelle und sind unregelmäßiger ausgerichtet; die linsenförmigen Xanthophoren werden plattenförmig. Der Wechsel von grüner zu grauer Färbung scheint stets über Schwarzgrün oder Dunkelolivgrün zu gehen. Die Xanthophoren keilen sich dann zwischen die Iridophoren ein und liegen in der grauen Haut oft unterhalb der letzteren; die Pterinosomen sammeln sich in der Peripherie der Zelle, während sich die Carotenoidvesikel um den Kern herum häufen. Die Iridophoren in der grauen Haut sind fast kugelförmig mit Purintäfelchen in konzentrischen Schichten. Eine hellgraue Färbung geht aus einer dunkelgrauen durch Aggregation der Melanosomen hervor. Die Chromatophorenwerte (“chromatophore values”), die Nielsen und Dyck (1978) für Hyla cinerea definierten, sind auch für Hyla arborea verwendbar; die Annahmen, die diesen Werten zugrunde liegen, werden jetzt ultrastrukturell gestützt.
    Notes: Summary The structural changes in the chromatophores of Hyla arborea related to changes in skin color were studied by electron microscopy and reflectance microspectrophotometry. During a change from a light to a darker green color, the melanosomes of the melanophores disperse and finally surround the iridophores and partly the xanthophores. The iridophores change from cup-shape to a cylindrical or conical shape with a simultaneous change in the orientation of the platelets from being parallel to the upper surface of the iridophores to being more irregular. The xanthophores change from lens-shape to plate-shape. The color change from green to grey seems always to go through a transitional black-green or dark olive green to dark grey. During this change the xanthophores migrate down between the iridophores, and in grey skins they are sometimes found beneath them. The pterinosomes gather in the periphery of the cell, while the carotenoid vesicles aggregate around the nucleus. The iridophores in grey skin are almost ball-shaped with concentric layers of platelets. A lighter grey color arises from a darker grey by an aggregation of melanosomes. The chromatophore values previously defined for Hyla cinerea are applicable in Hyla arborea, and the ultrastructural studies support the assumptions previously made to explain these values.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236162
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  • 99
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    The tegmental reticular nucleus: a cytoarchitectonic, golgi, fluorescence histochemical and ultrastructural analysis (1978)
    Springer
    Cell & tissue research 194 (1978), S. 463-479 
    Details
    ISSN: 1432-0878
    Keywords: Tegmental reticular nucleus (Bechterew) ; Serotonin neurons ; Reticular formation ; Ultrastructure ; Synaptic organization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The organization of the tegmental reticular nucleus of von Bechterew (TRN) has been analyzed in Nissl and Golgi material, by fluorescence histochemistry, and by electron microscopy. In the albino rat, the TRN situated in the ventral paramedian midbrain and pontine reticular formation, contains two principal types of neurons. The first is a population of large multipolar neurons (40–80 μm diameter) with abundant Nissl substance and 4–7 smooth dendrites which may extend up to 500 μm in length. The second is medium-sized fusiform neurons (14–40 μm diameter) with less Nissl substance and two primary dendrites that originate from each pole of the soma and have a more closely ramifying dendritic field. Fluorescence histochemistry demonstrates that serotonin neurons constitute one component of the medium-sized neuron group. A third neuronal type, infrequently encountered at the outer margins of the nucleus, corresponds to the large, multipolar isodendritic neurons (soma diameter 40–80 μm) of the pontine reticular formation. Ultrastructural analysis of the TRN also demonstrates large and medium sized neurons which are present, together with numerous large dendritic trunks, between bundles of myelinated axons traversing the TRN in both rostrocaudal and transverse planes. This distinctive arrangement produces the appearance of “gray islands” between myelinated axon bundles. Within these areas, abundant synaptic terminals occupy a large proportion of the available terminal space on the surface of dendrites and perikarya, particularly of the large type of neuron. Two types of synaptic terminals are encountered; S-type synapses contain lucent spherical synaptic vesicles and F-type synapses contain flattened lucent vesicles. In addition there is a small number of synaptic terminals with scattered 100–120 nm diameter dense core vesicles in a population of smaller pleomorphic vesicles. These account for no more than 10% of the synaptic terminal population.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236166
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  • 100
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    Histophysiological studies on the corpus allatum of Leucophaea maderae (1978)
    Springer
    Cell & tissue research 194 (1978), S. 533-545 
    Details
    ISSN: 1432-0878
    Keywords: Corpus allatum ; Insects ; Ovariectomy ; Ultrastructure ; Cytophysiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the corpora allata of 29 Leucophaea ovariectomized in the nymphal stage and maintained up to an adult age of 28 months was examined. In general, the subcellular morphology of these glands has much in common with that of normal female controls examined at the height of their activity. In addition, the most “typical”of the gonadectomy cases show certain distinctive features that are either absent or much less prominent in unoperated controls. Of primary interest is the striking abundance of smooth surfaced endoplasmic reticulum observed in many but not all of the castrates. Since this organelle is implicated in the biosynthesis of juvenile hormone, the factor normally responsible for yolk deposition, its increase, together with certain additional ultrastructural features, is indicative of an exceptionally high rate of hormone production. An explanation for the putative hyperactivity displayed to various degrees by the experimental animals may well be the constancy of the demand on their corpora allata, since removal of the ovaries abolishes the afferent signals in response to which, in the intact female, the brain turns off these glands during the long periods of gestation. That the synthetic effort may eventually level off, even in the absence of regular inhibitory stimuli, is suggested by the corpora allata of those castrates, the ultrastructure of which reflects moderate activity or possibly further regression
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236172
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