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  • Ultrastructure  (74)
  • Springer  (74)
  • 1980-1984  (74)
  • 1925-1929
  • 1983  (74)
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  • Springer  (74)
Years
  • 1980-1984  (74)
  • 1925-1929
Year
  • 1
    Electronic Resource
    Electronic Resource
    Electron microscopical study of self-differentiation potency in the chick embryonic endoderm cultured in vitro (1983)
    Springer
    Development genes and evolution 192 (1983), S. 171-178 
    Details
    ISSN: 1432-041X
    Keywords: Differentiation ; Digestive tract ; Endoderm ; Organ culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The self-differentiation potency of the endoderm of the chick embryo was investigated mainly by transmission electron microscopy. Endodermal fragments isolated from 4- to 6-day stomach or small intestine were cultured in the absence of mesenchyme and were able to differentiate in vitro into organ-specific epithelia. Endodermal fragments isolated from the stomach region differentiated into a pseudo-stratified epithelium with periodic acid Schiff-positive mucous granules in the apical cytoplasm, while those from the small intestinal region differentiated into a simple columnar epithelium with a striated border which was positive in alkaline phosphatase activity. These features are comparable with those of the mucous secretory epithelium of the normal embryonic stomach and the absorptive epithelium of normal embryonic small intestine, respectively. Next, the self-differentiation potencies were investigated of the upper and lower layers of the blastoderms, at stages 1–5 of Hamburger and Hamilton (H. and H.). Both stomach-type and small-intestine-type epithelia developed only when fragments of the lower layer isolated from the blastoderms older than stage 3 of H. and H. were cultured, suggesting that cells possessing the potency to differentiate into the stomach- and small-intestine-type epithelia exist in the definitive endoderm at the beginning of its formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848687
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of adenylate cyclase and cAMP phosphodiesterase in the gastrulating chick embryo (1983)
    Springer
    Development genes and evolution 192 (1983), S. 42-44 
    Details
    ISSN: 1432-041X
    Keywords: Chick embryo ; Gastrulation ; Adenylate cyclase ; cAMP phosphodiesterase ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructural localization of adenylate cyclase (E.C. 4.6.1.1.) and cAMP phosphodiesterase (PDE) (E.C. 3.1.4.17.) in the ectoderm of the developmental stage 4 chick embryo was studied. Adenylate cyclase was localized in the lateral surfaces of the ectodermal cells. In the primitive streak cells the enzymatic activity was observed on all the lateral surfaces, whereas in the periphery of the blastoderm the reaction product was localized in the apical parts of the lateral plasma membranes only. cAMP PDE localized in the apical cytoplasm of the ectodermal cells, with highest activity in the globular projections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848768
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructure of tuberculate spores in Streptomyces thermoviolaceus (1983)
    Springer
    Archives of microbiology 134 (1983), S. 295-298 
    Details
    ISSN: 1432-072X
    Keywords: Actinomycetes ; Streptomyces thermoviolaceus ; Sporogenesis ; Spore ornamentation ; Cupular knobs ; Sheath ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sporogenesis of aerial spores in Streptomyces thermoviolaceus corresponded to a common sporulation type in the genus. The sporulation septum was composed of an outer ring-shaped constriction wall and an inner interspace septum arising by the inwards growth of a double annulus. In mature spores the wall was composed of two layers, the outer one was part of the parent hyphal wall and septum material, the inner one was formed de novo. The spore chains were enclosed by the thin breakable sheath containing small rod-like elements. The ornamentation in the form of knobs, which were a characteristic feature of the species originated from the sheath. The knobs were hemispherical particles with an inner electron dense core and an outer electron transparent shell. The term “cupular knobs” was suggested for this type of tuberculate ornamentation. Frequently, the knobs became detached from the surface in which case the inner core separated easily from the shell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00407805
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  • 4
    Electronic Resource
    Electronic Resource
    Chroococcus S24 and Chroococcus N41 (cyanobacteria): morphological, biochemical and genetic characterization and effects of water stress on ultrastructure (1983)
    Springer
    Archives of microbiology 135 (1983), S. 81-90 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Ultrastructure ; Nitrogen fixation ; Water stress ; Taxonomy ; DNA ; Plasmids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two strains of desiccation-tolerant coccoid cyanobacteria, Chroococcus S24, a marine form, and Chroococcus N41, a cryptoendolith isolated from a hot-desert rock, have been characterized. The mol % DNA base compositions of the strains are 47.1 and 48.9% respectively. Plasmid DNA was not detected in either strain. The pigment contents and nutritional characteristics of the strains are identical. Both lack phycoerythrinoid pigments and, in culture, behave as slow-growing halotolerant marine forms with elevated requirements for Na+, Cl−, Mg2+ and Ca2+. Sucrose was the only carbon source of those tested that supported photoheterotrophic growth. Each strain synthesizes nitrogenase under anaerobic conditions but not in air. Morphologically the two strains are indistinguishable. They are considered to be independent isolates of the same cyanobacterial species. Chroococcus N41 was studied in detail with the electron microscope. When brought to equilibrium at matric water potentials of-168 MPa and lower (to-673 MPa=c0.12a w) the protoplast shrinks, but the cells maintain the same size and diameter as those at-2,156 kPa (MN medium; control); the sheath expands and remains attached to the cell wall outer membrane by fibrils. The cell wall, cell membrane, thylakoid membranes, cyanophycin granules and carboxysomes appeared intact in desiccated cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408014
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  • 5
    Electronic Resource
    Electronic Resource
    Some aspects of the development of the endodermis and cortex ofTilia cordata andPicea sitchensis (1983)
    Springer
    Plant and soil 71 (1983), S. 147-153 
    Details
    ISSN: 1573-5036
    Keywords: Cortex ; Endodermis ; Picea sitchensis ; Tilia cordata ; Transfer cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The endodermis of bothTilia cordata andPicae citchensis progressess through 3 characteristic phases of development. These developments are delayed somewhat in the xylem pole endodermis ofT. cordata, while inP. sitchensis 3–5 passage cells are found. The cortex ofT. cordata is characterised by very thick walls, while that ofP. sitchensis is characterised by a thick walled layer just outside the endodermis and by 2–3 outer layers of transfer cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182649
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  • 6
    Electronic Resource
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    Changes in plastid ultrastructure during iron nutrition-mediated chloroplast development (1983)
    Springer
    Protoplasma 114 (1983), S. 85-92 
    Details
    ISSN: 1615-6102
    Keywords: Chloroplasts ; Iron stress ; Sugar beet ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When grown in iron-free media, the youngest leaves of healthy green sugar beet plants became completely yellow after 6 to 8 days. This chlorosis was quickly reversed by resupplying iron. A study of the ultrastructure of the iron -stressed leaves revealed apparently normal subcellular organization except for the plastids which were small and undeveloped, contained a rudimentary, disorganized grana-fretwork and clusters of vesicles in the periphery. Twelve to 16 hours after resupply of iron, aggregates of phytoferritin were observed in the stroma, and the granal fretwork underwent further development. There was an increased orientation of the membranes along the long axis of the plastids and an increase in the length of the individual grana stacks. By 48 hours, leaf chlorophyll content was about 40% of the control. At the ultrastructural level, parallel alignment of membrane orientation was complete and the grana stacks began to increase in the number of thylakoids per stack.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279871
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  • 7
    Electronic Resource
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    The structure and histochemistry of sclerotia ofSclerotinia minor Jagger III. Changes in ultrastructure and loss of reserve materials during carpogenic germination (1983)
    Springer
    Protoplasma 117 (1983), S. 214-225 
    Details
    ISSN: 1615-6102
    Keywords: Histochemistry ; Sclerotia ; Sclerotial germination ; Sclerotinia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cytoplasmic reserves and extracellular substances were progressively broken down and utilized during carpogenic germination of sclerotia ofSclerotinia minor. Glycogen, wall polysaccharides and polyphosphate granules were removed first from regions of the sclerotium distant from developing apothecia, while protein bodies near the base of apothecial stipes were hydrolysed before those further away. The number of profiles of mitochondria and endoplasmic reticulum in cortical and medullary hyphae increased at the onset of germination, indicating increased metabolism in the hyphae. In contrast to developing sclerotia, simple pores with Woronin bodies were frequent in walls and septa during germination. Hyphae that appeared to converge towards the base of apothecial initials retained their cytoplasm and organelles until late in germination and hydrolysis of their reserves was delayed; these are interpreted as translocatory hyphae, although further work is required to determine their role unequivocally. When apothecia were fully developed, hyphae throughout the sclerotium were empty and the walls and extracellular matrix of cortical and medullary hyphae had almost completely broken down.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01281825
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  • 8
    Electronic Resource
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    Microtubule organization and morphogenesis in young spores of the mossTetraphis pellucida Hedw (1983)
    Springer
    Protoplasma 116 (1983), S. 115-124 
    Details
    ISSN: 1615-6102
    Keywords: Microtubules ; Moss ; MTOC ; Sporogenesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Microtubule systems appear sequentially at the distal and proximal poles of tetrad members during mid-sporogenesis in the mossTetraphis pellucida Hedw. The distal microtubule system emanates from a microtubule organizing center (MTOC) located between the single plastid and the nucleus. The distal MTOC and associated microtubules, which appear immediately after cytokinesis, are ephemeral and do not appear to be associated with the deposition of exine occuring at the same time. The proximal microtubule system, which appears slightly later than the distal system, is a more stable component of mid-sporogenesis. The proximal MTOC is an irregularly lobed, patelliform aggregation of electron-dense granules located beneath the plasma membrane at the proximal spore pole. Several bundles of microtubules radiate from the proximal MTOC and traverse the cell, enclosing the nucleus in an cone of microtubules. The proximal microtubule system is thought to function in aperture development and organelle migration. The relatively large nucleus migrates a short distance in the small spore early in the tetrad stage and maintains its acentric position at the proximal pole throughout later stages of sporogenesis. The plastid migrates later in the tetrad stage from its meiotic position parallel to the distal surface to a position perpendicular to the distal surface with one tip in close proximity to the proximal MTOC. The proximal microtubule system reaches its maximum development by the end of the tetrad stage and all micrographic evidence of it is lost in the maturation stages of late sporogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279828
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  • 9
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    Ultrastructure of aerial stalk formation by the ciliated protozoanSorogena stoianovitchae (1983)
    Springer
    Protoplasma 116 (1983), S. 125-135 
    Details
    ISSN: 1615-6102
    Keywords: Ciliated protozoan ; Sorogenesis ; Extracellular matrix ; Secretion ; Extrusive organelles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sorogena stoianovitchae Bradbury andOlive is an unusual kinetophragminophoran ciliate characterized by the aggregation of individual trophic cells to form a multicellular sorogen that rises aerially from the medium surface to produce a sorocarp. A light and electron microscope study of sorogenesis revealed how the sorogenic cells produce the stalk. The feeding ciliates contain numerous subpellicular expansions of rough endoplasmic reticulum cisternae that are only one element of the secretory system necessary for stalk formation. Upon aggregation, the stalk secretory system develops further, initially with the proliferation of the subpellicular expansions. Then, during later aggregation and early sorogenesis, other secretory elements appear: stalk material vesicles, dense granule vesicles, and electron lucent vacuoles. These are all derived from the rough endoplasmic reticulum. Only the subpellicular expansions and stalk material vesicles appear to add to the stalk matrix. The dense granule vesicles could be precursors of the stalk material vesicles; the electron lucent vacuoles, which can be demonstrated to contain fibrillar material, are perhaps by-products of the secretory process. Sorogenesis inSorogena occurs by a mechanism unique among the stalk-producing protists that have been studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279829
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  • 10
    Electronic Resource
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    Morphogenesis of coremia and rhizomorphs in the AscomyceteSphaerostilbe repens (1983)
    Springer
    Protoplasma 116 (1983), S. 99-114 
    Details
    ISSN: 1615-6102
    Keywords: Sphaerostilbe repens ; Ultrastructure ; Differentiation ; Coremia ; Rhizomorphs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The differentiating stages of coremia and rhizomorphs inSphaerostilbe repens were studied by transmission electron microscopy. Vegetative mycelium is characterized by highly cytoplasmic cells rich in ribosomes and mitochondria and with few vacuoles as well as endoplasmic reticulum. Cell walls are thin attaining a maximum thickness of 0.10 μm. During the aggregating phase a prosenchymatous mass of randomly oriented cells is produced by localized elongation and branching of the filaments. The hyphae in this region have the appearance of actively metabolising cells. In the course of the differentiating phase, numerous hyphae of the median zone of the aggregate grow upward and downward to give rise to coremium and rhizomorph primordia respectively. The individual hyphal tips lay parallel to each other and cells of the growing apices retain their meristematic characteristics. At the periphery of the aggregate and to a lesser extent in the subapical rhizomorphic zone, cells reduce their cytoplasmic density as a consequence of a decrease in the number of ribosomes. These cells also increase in size and become isodiametric and vacuolated. During cellular differentiation walls increase steadily in thickness and at the elongating phase they reach 0.30 μm in the rhizomorphic cortex. Mucilaginous material is progressively deposited around hyphae and in the most differentiated zones, coalesce to fill interhyphal spaces. This extracellular matrix seems to play a role in maintaining cohesiveness of the aggregated organs. The tissue in the process of differentiation is scattered with cells highly enriched in mitochondria and with cells virtually undifferentiated. Accumulation of microfilaments takes place in the differentiating zone localized behind the immersed meristematic apex. These structures might be involved in wall synthesis. Glycogen rosettes accumulate in the vegetative mycelium surrounding the aggregating centers, suggesting the possibility of supplying energy during the differentiating processes. The vacuolar system, represented by autophagic vacuoles which are present until the differentiation phase, presumably may also participate in the biochemical changes that occur during aggregation. Coremial cells are characterized by an increase in wall thickness, a highly sinuous plasma-membrane as well as large amounts of mucilaginous compounds accumulated between hyphae, but in all other respects they resemble the cells of actively growing vegetative hyphae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279827
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  • 11
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    Stalk function during sorogenesis by the ciliated protozoanSorogena stoianovitchae (1983)
    Springer
    Protoplasma 116 (1983), S. 136-144 
    Details
    ISSN: 1615-6102
    Keywords: Stalk ; Ciliated protozoan ; Sorogenesis ; Extracellularmatrix ; Ultrastructure ; Secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The sorogenic cells of the haptorid ciliateSorogena stoianovitchae Bradbury andOlive secrete a hydrated, fibrillar matrix that becomes organized to form a stalk. This light and electron microscope study examines the role of the secreted stalk matrix in the development of the sorocarp. The stalk material is secreted as a compact clump or clumps of material that expands as it hydrates. The expanded stalk material is initially viscous, but soon, through dehydration or cross-linking, solidifies to form a sheath. The sheath is the outside layer of the stalk, provides structural support, and controls the expansion of the newly secreted stalk material. The sorogenic cells continue to secrete stalk material that expands once it is outside of the cell. The resulting expansion force is directed upward by the sheath, thereby moving the cells further above the surface. The continued dehydration of the sheath material provides an inwardly directed force that also contributes to the upward movement of the sorogen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279830
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  • 12
    Electronic Resource
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    Ultrastructural demonstration of loss and recovery of cytochrome oxidase activity during and after heat induction of microcycle conidiation inNeurospora crassa (1983)
    Springer
    Protoplasma 116 (1983), S. 149-154 
    Details
    ISSN: 1615-6102
    Keywords: Cytochrome oxidase ; Cytochemistry ; Ultrastructure ; Neurospora ; Heat treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cytochrome oxidase (EC 1.9.3.1) activity of conidia of wild-typeNeurospora crassa was detected cytochemically at the ultrastructural level by 3,′-diaminobenzidine (DAB) reaction during heat treatment at 46 °C and after shift down to 25 °C. At 46 °C the decrease in the enzyme activity was shown to be time-dependent (0–10 hours) in the progressively overswelling conidia. Gradual recovery of the DAB reaction occurred in mitochondria of conidia outgrowing conidiogenous germ tubes (microcycle conidiation) when shifted down to 25 °C. Inactivation of cytochrome oxidase was efficiently prevented during heat treatment in the presence of Tween 20. Such conidia no longer overswelled but still required shift down to 25 °C to produce germ tubes with delayed conidiogenous ability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279832
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  • 13
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    The effect of UV-B and UV-C radiation on sugar beet leaves (1983)
    Springer
    Protoplasma 117 (1983), S. 7-16 
    Details
    ISSN: 1615-6102
    Keywords: Beta vulgaris ; Chloroplast ; Ultrastructure ; Ultraviolet radiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effect of UV-C (254 nm) and UV-B (290–320 nm) radiation on leaves ofBeta vulgaris L. at the ultrastructural level was investigated. Although the damage caused by UV-C radiation was more striking than that resulting from UV-B radiation, several structural changes were seen in the UV-B treated material. Generally the effects of UV-B and UV-C radiation were different, suggesting different mechanisms of action, discernible even at the ultrastructural level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01281779
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  • 14
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    The ultrastructure of the formation and development of the amoeboid tapetum inArum italicum miller (1983)
    Springer
    Protoplasma 117 (1983), S. 116-129 
    Details
    ISSN: 1615-6102
    Keywords: Pollen ; Amoeboid tapetum ; Arum italicum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A tapetum is found around all higher plant meiocytes and is thought to nourish them. It may, in turn, be influenced by their development. The mature tapetal membrane in amoeboid (or periplasmodial) tapeta, of whichArum italicum is an example, fits closely around the developing meiocyte. This description of tapetal ultrastructure starts from the meiotic prophase when the tapetum is still cellular and comprises two rows of cells on the inside of the tetrasporangiate anther. The radial walls of the still cellular tapetum start to dissolve during leptotene of the first meiosis. The lysis begins in the middle lamella in those areas penetrated by the most plasmodesmata. The walls in contact with the meiocytes on the other hand do not disappear until after the first meiosis. At telophase the now fused cytoplasmic tapetal mass begins to extend its joint plasmamembrane, amoeboid fashion, into the loculus. A cluster of microtubules can be seen at the apex of this intrusion apparently initiating or maintaining the shape of the invading plasmamembrane front. The tapetum now adheres closely to the microspores. The tapetal zone closest to the spores has a prominent population of microtubules and just a little ER, whereas the outer zone away from the spores contains all the other organelles. The inner zone, in a squash preparation, is not readily separated from the spores. The microtubules, at the middle microspore stage, are no longer to be seen in a circle around the microspores, but spread out with some lying orthogonal to the now-forming exine surface. In places the tapetal plasmamembrane begins to retract from the exine leaving roughly cone-shaped zones (spines) which become filled with fibrillar material. This material begins to be deposited on the exine surface. These “spines” are both PAS. and Coomassie-blue positive and susceptible to acetolysis.
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    URL: http://dx.doi.org/10.1007/BF01288350
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  • 15
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    Nucleolus-associated bodies (karyosomes) in dividing and differentiating plant cells (1983)
    Springer
    Protoplasma 115 (1983), S. 1-10 
    Details
    ISSN: 1615-6102
    Keywords: Brassica napus ; Nucleolus ; Pisum sativum ; Ultrastructure ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The karyosome is a spherical body up to 1 μm in diameter that lies on the nucleolus of certain plant species, particularly those with a relatively low nuclear DNA content and an areticulate nuclear structure. It can be seen in the light microscope after impregnation with silver; in the electron microscope its structure consists of fibrillo-granular material. Nucleoli of cells in root apices may bear 0, 1, or 2 karyosomes. The frequency with which these numbers of karyosomes are observed depends on the location of the cells within the apex. In roots ofPisum sativum andZea mays the nucleoli of both slowly-dividing and young differentiating cells bear karyosomes more frequently than the nucleoli of rapidly-dividing cells. The karyosome seems to adopt a preferred location on the nucleolus, lying most frequently on the nucleolar surfaces directed towards the apex or base of the root. The origin and functional significance of the karyosome are discussed. Morphological evidence suggests that it may be material that formerly was part of a fibrillar centre.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01293574
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  • 16
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    Stomatal pore and cuticle formation inFunaria (1983)
    Springer
    Protoplasma 116 (1983), S. 1-13 
    Details
    ISSN: 1615-6102
    Keywords: Cuticle ; Peristomatal transpiration ; Stomata ; Ultrastructure ; Funaria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cuticle and pore development in the guard cells ofFunaria were investigated with the electron microscope. Pore cuticle formation is simultaneous with the creation of the pore itself. The morphology of the pore cuticle is unlike that of any cuticle described in the literature. It has many lamellae which are penetrated by electron dense fibrils. Three different cuticular morphologies exist from the pore to the subsidiary cell walls. The cuticles on the pore and outer walls contain fibrils that sometimes reach to the surface. The subsidiary cell cuticle lacks fibrils altogether. It is hypothesized that (1) cuticularization of the middle lamella contributes to ventral wall separation and (2) differences in extent of cuticular fibrils are related to greater water loss from stomata than from subsidiary cells (peristomatal transpiration).
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    URL: http://dx.doi.org/10.1007/BF01294225
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  • 17
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    Mitosis in the freshwater red algaBatrachospermum ectocarpum (1983)
    Springer
    Protoplasma 118 (1983), S. 56-70 
    Details
    ISSN: 1615-6102
    Keywords: Carposporophyte ; Cell division ; Mitosis ; Rhodophyta ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitotic ultrastructure was observed in meristematic cells of carposporophyte generations of the freshwater red algaBatrachospermum ectocarpum. Prior to nuclear division, cell elongation occurs resulting in the nucleus being located at the proximal end of the cell and separated by a large central vacuole from a distal “empty region” which the daughter nucleus eventually occupies. In late prophase, nuclear envelope-attached polar rings are situated adjacent to shallow nuclear invaginations. At prometaphase the nuclear invaginations extend deeply into the nucleus forming continuous cytoplasmic channels containing microtubules. Perinuclear ER and a typical equatorial chromosomal plate are formed by metaphase at which time the nuclear envelope lining the cytoplasmic channels has dispersed. Chromosomal and non-chromosomal microtubules converge at the poles where a single, large gap is seen in the otherwise intact nuclear envelope. Polar rings were not detected in the few mitotic cells observed beyond prometaphase but are thought to be present. During anaphase an interzonal midpiece is formed and the distal-most incipient daughter nucleus moves laterally past the central vacuole into the apical “empty region”. Features of mitosis inBatrachospermum are believed to be intermediate between those exhibited by the lower and higher orders of red algae, this being consistent with the taxonomic placement of the genus in theNemaliales, the least advanced order of the classFlorideophyceae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01284747
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  • 18
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    The ultrastructure of nuclear bodies in interphase plant cell nuclei (1983)
    Springer
    Protoplasma 118 (1983), S. 95-103 
    Details
    ISSN: 1615-6102
    Keywords: Nuclear bodies ; Nucleolus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nuclear bodies are found in interphase nuclei of root apices of a number of plant species. They often show differences in structure and position relative to the nucleolus and this has led to an attempt to define two classes of body. However, in some species their separation into two classes on structural grounds alone breaks down, indicating that although they may occupy different positions within the nucleus they may in these particular cases be only different forms of the same body. The two extremes of the range of bodies examined represent what have been called “nucleolus-associated body” (karyosome) and “dense body”. The nucleolus-associated body is typically attached to, or adjacent to, the nucleolus. It is composed of fibrils 4–8 nm wide and often has an open structure showing compound threads or fibrils separated from each other by electron-lucent spaces. The dense body is more compact in structure and typically lies free in the nucleoplasm. Both types of body have an affinity for silver ions which, together with their staining reaction following treatment with EDTA, indicates that they consist of ribonucleoprotein. The characteristics of nuclear bodies found in different plant species have some relationship with the structure and DNA content of the interphase nucleus. Nucleolus-associated bodies are characteristic of species with an areticulate nuclear structure (2 C DNA content 〈6 pg), while dense bodies are common in species with a reticulate nuclear structure (2 C DNA content 〉6 pg). The possible functions of the two forms of nuclear body are discussed.
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    URL: http://dx.doi.org/10.1007/BF01293065
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  • 19
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    Ultrastructural polysaccharide localization in calcifying and naked cells of the coccolithophoridEmiliania huxleyi (1983)
    Springer
    Protoplasma 118 (1983), S. 157-168 
    Details
    ISSN: 1615-6102
    Keywords: Calcification ; Coccolithophorids ; Polysaccharide localization ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Emiliania huxleyi is a marine coccolithophorid which produces coccoliths,i.e., particles consisting of calcite and macromolecular organic material. The coccoliths are formed intracellulary in specialized organelles which comprise a coccolith vesicle (CV) and a reticular body (RB), together forming the CV/RB system or calcifying system. After termination of calcification, the coccolith is extruded and incorporated into the coccosphere,i.e., one or several layers of extracellular coccoliths surrounding the cell. Apart from the coccolith-producing cells (C cells) ofE. huxleyi, there are naked cells (N cells) which seem to have lost the capacity to produce coccoliths but are very similar to the C cells in other morphological respects. Biochemical studies have revealed that polysaccharides may play a regulatory role in calcification. The aim of the present study was to determine the localization of polysaccharides in both C and N cells electron microscopically. For this purpose, a cytochemical staining technique according toThiéry (1967) was applied. The CV/RB system of C cells was conspicuously stained. Due to the excellent stainability of this system, a putative succession of morphological stages during coccolithogenesis could be described. The staining pattern of the N cells closely resembled that of the C cells. It was found, however, that the “calcifying” system of N and C cells differed in both morphology and position. It is suggested that the divergent morphology of the “calcifying” system of N cells accounts for its failure to produce coccoliths.
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    URL: http://dx.doi.org/10.1007/BF01293073
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    Ultrastructure of the kidney of the marine teleost Sparus auratus: The renal corpuscle and the tubular nephron (1983)
    Springer
    Cell & tissue research 228 (1983), S. 99-106 
    Details
    ISSN: 1432-0878
    Keywords: Kidney, teleost (Sparus auratus) ; Ultrastructure ; Renal corpuscle ; Tubular nephron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the renal corpuscle and tubule of Sparus auratus is described. The parietal epithelium in Bowman's capsule is flattened with occasional cilia; podocytes are large with bundles of perinuclear microfilaments, a large vacuole and occasional cilia; a filtration slit membrane can sometimes be identified; mesangial cells are placed peripherally and among the walls of the capillaries. The neck segment is short and ciliated; it lacks the mucous cells which appear in some teleosts. The first proximal segment has columnar cells with a well developed brush border, and some cilia, large light vacuoles and many lysosomes appear in the apical zone; the second proximal segment has taller cells than the former, which appear with a less dense brush border, containing numerous multivesicular bodies; the third proximal segment, which has cells similar to the previous ones, possesses a less developed brush border and numerous mitochondria scattered all over the cytoplasm. No distal tubule is present. There is a collecting tubule with columnar cells with few microvilli and some apical mucin granules which empty into the collecting duct.
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    URL: http://dx.doi.org/10.1007/BF00206268
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    Ultrastructure of trout spermatozoa: Changes after dilution and deep-freezing (1983)
    Springer
    Cell & tissue research 228 (1983), S. 205-218 
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    ISSN: 1432-0878
    Keywords: Spermatozoa ; Ultrastructure ; Deep-freezing ; Sperm manipulation ; Trout
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Trout spermatozoa taken from the testis, vas deferens and ejaculate are described at the ultrastructural level. The morphology of the spermatozoa head, changes in the middle-piece structure, and the relationship between the centrioles and the flagellum were studied under consideration of their role in the reproduction of this species. Morphological changes observed after dilution of the spermatozoa in freshwater or saline and subsequent freezing deserve attention in connection with certain manipulations used in fish farms and laboratories.
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    URL: http://dx.doi.org/10.1007/BF00204873
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    Ultrastructure of sensilla on the antennal pedicel of the brown planthopper Nilaparvata lugens Stal (Insecta: Homoptera) (1983)
    Springer
    Cell & tissue research 228 (1983), S. 313-322 
    Details
    ISSN: 1432-0878
    Keywords: Olfactory ; Sensilla ; Ultrastructure ; Insects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scanning- and transmission electron-microscope studies of the sensilla of the pedicel of Nilaparvata lugens have revealed an elaborate plaque organ and three structurally different types of trichoid hairs. Each plaque organ is innervated by 120–150 neurons arranged in groups. The porous sensory cuticle is folded into finger-like projections and is surrounded by protective non-sensory denticles. Trichoid sensilla differ in number of neurons, appearance of dendrites and arrangement of pores. Type I, innervated by 2 neurons, has pores along its length and is probably olfactory in function. Types II and III are innervated by one and five neurons, respectively, and the absence of pores along the hair shaft indicates a possible gustatory role. The importance of these sensilla is discussed with reference to the behaviour of this important insect pest.
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    URL: http://dx.doi.org/10.1007/BF00204881
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    Topography, ultrastructure and phagocytic capacity of avian lymph nodes (1983)
    Springer
    Cell & tissue research 228 (1983), S. 389-403 
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    ISSN: 1432-0878
    Keywords: Lymph node, avian ; Ultrastructure ; Macrophages ; Phagocytic capacity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the avian lymph node (ALN) is characterized by a thin capsule, thin lymphoreticular cords, and an absence of trabeculae. It is not possible to subdivide the ALN into cortex, paracortex and medulla, or to subdivide the system of sinuses into marginal, trabecular and medullary divisions. The lymphoreticular cords contain avian germinal centers (AGC) with B-lymphocytes and the area of T-lymphocytes. Postcapillary venules are responsible for the recirculation of lymphocytes. Sinus reticular cells do not exist in the ALN, but free macrophages are present. The phagocytic capacity of the macrophages was determined by injection of vital dyes (India ink, Berlin blue) and inoculation with Candida cells. Macrophages filled with markers migrate from the lymph sinuses into the lymphoreticular cords and further into the AGC. The mobility of the macrophages is remarkably lower after phagocytosis of Candida cells.
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    URL: http://dx.doi.org/10.1007/BF00204887
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    Changes in the satellite cells of the anuran tadpole tail muscles during metamorphosis (1983)
    Springer
    Cell & tissue research 228 (1983), S. 573-585 
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    ISSN: 1432-0878
    Keywords: Satellite cells ; Muscle fibres ; Anura ; Metamorphosis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The incidence and the ultrastructure of the satellite cells associated with red and white muscle fibres of the anuran (Rana japonica) tadpole tail were examined in three stages (hindlimb-bud, prometamorphic, and climax) during metamorphosis. In these three stages the satellite cells are found more frequently in the red fibres than in the white fibres. As metamorphosis proceeds, the incidence of the satellite cells decreases in both red and white fibres. The satellite cells in the hindlimb-bud stage have abundant cytoplasm rich in organells. Cisternae of rough endoplasmic reticulum are often dilated. The intercellular space between the satellite cell and the muscle fibre is narrow and relatively constant (15–25 nm). Some satellite cells appear to be in the process of fusion with the muscle fibre. Cytoplasmic volume and organellar content are gradually reduced during metamorphosis. In the prometamorphic and climax stages, the intercellular space is in general gradually extended. It often exceeds 0.5 μm, and usually contains the basal lamina and fibrous materials. Some satellite cells have cytoplasmic processes that project into the interstitial space through a gap in the basal lamina.
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    URL: http://dx.doi.org/10.1007/BF00211477
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    Morphogenesis of nuclear polyhedrosis virus from Autographa californiea in a cell line from Mamestra brassicae (cabbage moth) (1983)
    Springer
    Cell & tissue research 228 (1983), S. 587-595 
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    ISSN: 1432-0878
    Keywords: Virus morphogenesis ; Baculoviridae ; Ultrastructure ; Cell culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cultures of cell line IZD-MB 0503 from Mamestra brassicae were inoculated with nonoccluded nuclear polyhedrosis virus of Autographa californica (AcNOV). At 1 h postinoculation (p.i.) nucleocapsids were found in the cytoplasm near nuclear pores and within the nucleoplasm. Formation of virogenic stroma was observed at 7 h p.i. The first short empty capsids were seen at 10 h postinoculation (p.i.), followed by partially and completely filled nucleocapsids (11–12h p.i.) with most capsids filled at 12h and later. This suggests that nucleocapsid components, such as capsid and DNA-core, assemble in successive stages rather than simultaneously. Viral progeny, being released from the cells by budding, were observed at 13h p.i.
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    URL: http://dx.doi.org/10.1007/BF00211478
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    Structure of the pars distalis in the adult tammar wallaby (Macropus eugenii) (1983)
    Springer
    Cell & tissue research 229 (1983), S. 155-174 
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    ISSN: 1432-0878
    Keywords: Pituitary ; Tammar wallaby ; Marsupialia ; Ultrastructure ; Immunohistochemistry ; Cell types
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An immunohistochemical, light- and electron-microscopial study was made of the pars distalis in adult tammar wallabies (Macropus eugenii). The pars distalis of this marsupial mammal was divided into three regions, based on the distribution of cell types within the gland. Somatotropic, mammotropic, luteotropic, folliculotropic, corticotropic and thyrotropic cells were identified on the basis of their immunohistochemistry, cytology and ultrastructure. Non-granulated (folliculo-stellate) cells, identified in electron micrographs, were found throughout the pars distalis. Somatotropic cells were predominant in the posterior pars distalis in all animals examined. In the single male specimen and in the non-lactating females examined, small numbers of apparently inactive mammotropic cells were scattered throughout the pars distalis; the same cell type was apparently active and present in considerable numbers in lactating females. Only one morphological type of gonadotropic cell was evident; these cells were scattered throughout the pars distalis, but in largest numbers in the median region. Small numbers of thyrotropic cells were found, most commonly in the anterior pars distalis. Corticotrops were also observed in moderate numbers, predominantly in the anterior regions of the pars distalis.
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    URL: http://dx.doi.org/10.1007/BF00217888
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    Differentiation and transdifferentiation of adrenal chromaffin cells of the guinea pig (1983)
    Springer
    Cell & tissue research 229 (1983), S. 299-308 
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    ISSN: 1432-0878
    Keywords: Adrenal chromaffin cells ; Plasticity ; Transplants ; Kidney capsule ; Ultrastructure ; Catecholamine biochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histochemical, ultrastructural and biochemical studies (quantitative determinations of catecholamines (CA) and phenylethanolamine N-methyltransferase (PNMT) activity) were carried out on autologous transplants of adult guinea-pig adrenal medulla under the kidney capsule, in order to investigate the specific influences of a virtually nerve-free environment in comparison to those mediated by a densely innervated one such as in the iris (cf. Unsicker et al. 1981). Three weeks after transplantation chromaffin cells survived well, most cells maintaining their morphological identity in terms of adrenaline (A) storage, although biochemically measured A and PNMT had dramatically decreased. Chromaffin cells in transplants extended neurite-like processes in an identical fashion as seen in transplants to the anterior chamber of the eye and in culture. Chromaffin cells were frequently connected by synaptoid contacts, but did not receive cholinergic synapses as observed in transplants to the iris. It may be concluded that the growth factor(s) eliciting neurite outgrowth from transplanted chromaffin cells are rather ubiquitously present, independent of whether the transplantation site is sparsely or richly innervated.
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    URL: http://dx.doi.org/10.1007/BF00214977
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    Immunocytochemical localization of enkephalin in the lateral septum of the guinea-pig brain (1983)
    Springer
    Cell & tissue research 228 (1983), S. 265-276 
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    ISSN: 1432-0878
    Keywords: Met- and leu-enkephalin ; Immunocytochemistry ; Ultrastructure ; Lateral septum ; Guinea-pig brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By the use of antisera to met-enkephalin and leu-enkephalin, enkephalin-containing structures were visualized in the lateral septum of the guinea-pig brain. The present results do not reveal immunoreactive perikarya in this area. The immunostaining is exclusively located in numerous nerve fibers and endings mostly encompassing neuronal perikarya, which accounts for the fact that at the light-microscopic level cellular somata appear to be immunostained. The immunoreactive terminals and fibers contain granules approximately 110nm in diameter and synaptic vesicles. The origin and the functional role of these numerous enkephalin terminals remain to be established. This work was supported by a grant from INSERM N∘ 804012
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    The effects of colchicine on the distribution of glycoprotein-containing vesicles in epithelial cells of the murine colon (1983)
    Springer
    Cell & tissue research 228 (1983), S. 323-335 
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    ISSN: 1432-0878
    Keywords: Ultrastructure ; Colonic epithelium ; Colchicine ; Vesicles ; Glycoproteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In murine colonic epithelial cells, cell-coat glycoproteins are transported to the cell surface in vesicles that originate at the Golgi apparatus. To determine the role of microtubules in the movement of these vesicles the antimicrotubule agent colchicine was injected into mice at several time intervals prior to sacrifice. In the mice that were treated with colchicine for 4.5 h it was observed that the polarity of the cells was disturbed. The Golgi apparatus and nucleus often appeared interchanged in their positions. The glycoprotein-containing vesicles, normally located apically, were sparse in that location, but abundant near the lateral plasma membranes of the cells at the level of the nucleus and Golgi apparatus. Staining by the periodic acid-chromic acid-silver methenamine technique for glycoproteins clearly revealed the reduction of vesicles apically and accumulation of vesicles laterally. The mechanism responsible for the movement of the vesicles to this location is unclear. It is suggested that the accumulation of vesicles in the lateral region may reflect some hindrance in the fusion of the vesicles with the lateral cell membranes.
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    Ontogeny of the photoreceptors in the embryonic retina of the viviparous guppy, Poecilia reticulata P. (Teleostei) (1983)
    Springer
    Cell & tissue research 230 (1983), S. 469-486 
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    ISSN: 1432-0878
    Keywords: Ontogeny ; Photoreceptors ; Retina ; Ultrastructure ; Teleosts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural analyses of retinal development in the guppy embryo show that at midgestation all types of photoreceptors are differntiated in the fundus, and at birth differentiation extends over the whole retina. Formation of discs of outer segments is more rapid in rods than in cones. Double cones differentiate simultaneously with long single cones and are formed by the adhesion of two primordial inner segments; short single cones develop last. Wherever cones are differentiated, they are arranged in an adult-type square mosaic. The rods in the embryo, as opposed to the adult, are likewise regularly arranged within the mosaic unit. These results are at variance with the generally held opinion that adult teleosts which possess duplex retinae have larvae with pure cone retinae, and that rods, double cones and mosaics appear in late larval life or only at metamorphosis. In the double cones of the guppy embryo subsurface cisternae develop along the adjoining primordial inner segments. Additionally, regularly distributed subsurface cisternae are formed in the regions of intimate contact of long single cones with double cones and rods. We suggest that the early development of rods and double cones, and a square-mosaic with regular distribution of rods and subsurface cisternae, provide the newly born with a fully functional optical apparatus, especially suited to perception of movements. This is necessary for its survival against predatory, especially maternal, attacks.
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    URL: http://dx.doi.org/10.1007/BF00216193
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    Ultrastructural evidence of variation in the number of secretory granules within the granulosa cells of the sheep corpus luteum (1983)
    Springer
    Cell & tissue research 230 (1983), S. 631-638 
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    ISSN: 1432-0878
    Keywords: Corpus luteum ; Ultrastructure ; Secretory granules ; Hormones ; Quantitative study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The granulosa luteal cells of the sheep corpus luteum secrete their hormonal products by exocytosis of granules. Electron micrographs of randomly selected granulosa cells from nine corpora lutea at day 10 of the oestrous cycle were examined to obtain the cellular density of these granules. From the area of the cell, calculated using an x -y digitiser, and the number of granules observed, the number of intracellular secretory granules per μm3 of luteal cell cytoplasm was calculated. There was a large variation in the number of granules per cell within the same corpus luteum and between corpora lutea taken at the same stage of the cycle. The number of intracellular granules in nine corpora lutea varied from 2.12±1.05 granules per μm3 (x, SD, n = 30) cells to 0.36±0.18 granules per μm3 ( x, SD, n = 26). These morphological data suggest that the variation in granule synthesis in individual cells may contribute to the variation in hormone content of corpora lutea at the same stage of the cycle, and the episodic release of hormone into the plasma.
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    URL: http://dx.doi.org/10.1007/BF00216206
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    Ultrastructure and differentiation of ascidian muscle (1983)
    Springer
    Cell & tissue research 230 (1983), S. 77-94 
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    ISSN: 1432-0878
    Keywords: Ascidian larva ; Embryology ; Myogenesis ; Somatic striated (skeletal) muscle ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The larval muscle cells of Diplosoma macdonaldi contain subcortical and medullary myofibrils which are invested by fenestrated sheets of the sarcoplasmic reticulum. Cisternae of the sarcoplasmic reticulum are coupled with tubular invaginations of the sarcolemma. To appreciate better such uncommon features of cellular organization, six embryonic stages were selected for an ultrastructural study of myogenesis. The proliferative, synthetic, and elaborative phases of myogenesis were represented by embryos ranging from neurulae to prehatching larvae. The contractile apparatus originates during the synthetic phase of myogenesis, when thick and thin myofilaments appear in the cortical sarcoplasm at the epidermal and notochordal poles of the cell. The myofilaments promptly aggregate into unstriated fascicles, and the fascicles unite in series to establish the rudimentary myofibrils. All major sarcomeric bands, except the Z-lines, are evident along the myofibrils. Cisternae of the sarcoplasmic reticulum form peripheral couplings with the overlying sarcolemma, and they also form interior couplings with sarcolemmal invaginations from the ends of the cell. The interior couplings localize over the I-bands of the myofibrils. In the elaborative phase of myogenesis, mitochondria invade the cortical sarcoplasm, and the contractile apparatus passively shifts to the subcortex and medulla of the cell. Relocation of the myofibrils coincides with the disappearance of all peripheral couplings. Cisternae of the sarcoplasmic reticulum anastomose around the myofibrils, creating the fenestrated sheets that extend between sarcomeres. As Z-lines begin to bisect the I-bands, the perifibrillar cisternae become confluent with the cisternae in the precocious interior couplings.
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    Ultrastructural studies on sporogony of Babesia microti in salivary gland cells of the tick Ixodes dammini (1983)
    Springer
    Cell & tissue research 231 (1983), S. 275-287 
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    ISSN: 1432-0878
    Keywords: Babesia ; Tick ; Sporogony ; Salivary gland ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Tick larvae were permitted to feed on infected hamsters and then allowed to molt. Nymphs were examined just prior to feeding on uninfected hamsters or at timed intervals thereafter. Invasion of the salivary gland by B. microti occurs before feeding of the nymph begins, and development of the parasite is further stimulated by feeding. The sporoblast forms a massive multinucleated meshwork which ramifies throughout the large host cell. No separation of the meshwork into multiple subdivisions, termed “cytomeres” by other workers, has been detected. Instead the specialized organelles characteristic of sporozoites, namely micronemes, rhoptries, and segments of double membrane appear in the meshwork itself and gradually become organized into sporozoite anlagen which protrude from its surface. At the same time the meshwork shortens and thickens giving rise to large compact undifferentiated bodies whose surface is also studded with sporozoite anlagen. Sporozoites thus originate either from the meshwork or from the undifferentiated bodies. In either case large lobate nuclei send projections into the anlagen as they protrude from the surface of the sporoblast. In a final step the mature sporozoites arise by simultaneous nuclear and cytoplasmic divisions. There is no separate stage of schizogony and the process is one of true budding.
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    Ultrastructure of sensory receptors on the labium of the rice brown planthopper (1983)
    Springer
    Cell & tissue research 230 (1983), S. 353-366 
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    ISSN: 1432-0878
    Keywords: Homoptera ; Labium ; Sensilla ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the sensory receptors located on the labium of the rice brown planthopper is described; possible functions of individual receptors are suggested on morphological grounds. Uniporous chemosensilla which may or may not possess a mechanoreceptive dendrite, domed multiporous chemosensilla, and mechanoreceptive pegs are present on the flattened labial tip. Mechanoreceptive pegs are distributed over the labium. The fine structure of a multilobed sensillum located on either side of the labium is also described.
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    Characterization of the population of phagocytic cells in thymic cell suspensions (1983)
    Springer
    Cell & tissue research 231 (1983), S. 313-323 
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    ISSN: 1432-0878
    Keywords: Thymus (rat) ; Cell suspensions ; Phagocytic cells ; Enzyme-and immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat thymic phagocytic cells were characterized in vitro using various light and electron-microscopical techniques. Thymic cell suspensions were mechanically prepared and enriched for non-lymphoid cells, which were predominantly phagocytic and of three types. Type I showed acid phosphatase (APh) activity in small granules dispersed throughout the cytoplasm and were mostly Ia antigen-positive, although the Ia membrane label varied in intensity and distribution among individual cells. Only a few cells had endogenous peroxidase activity. The type-I cells could not be clearly distinguished morphologically from type-II or -III cells, and most likely comprise precursors of both these cell types. Type-II were large pale cells with many slender cell processes. These cells had APh activity centrally positioned, were strongly positive for Ia on the cell membrane and were negative for endogenous peroxidase. The cytoplasm frequently contained Birbeck granules, which unequivocally classifies these cells as the in vitro equivalent of the interdigitating cells present in the medullary area of the thymus in situ. Type-III cells were rounded with a smooth or ruffled cell membrane and contained vacuoles and many phagolysosomes. They were strongly positive for APh which was present throughout the cytoplasm. About 50% of these cells were positive for endogenous peroxidase in a pattern resembling resident macrophages. The cells were negative for Ia antigens. Type-III cells mostly likely represent the macrophages found in the cortical area of the thymus.
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    Trophospongium-like structures in an insect eye: Response of retinula cells of Papilio xuthus (Lepidoptera) to irradiation with ultraviolet light (1983)
    Springer
    Cell & tissue research 231 (1983), S. 519-526 
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    ISSN: 1432-0878
    Keywords: UV-irradiation ; Compound eye Rhabdomeres ; Trophospongium ; Ultrastructure ; Lepidoptera, Insecta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Presumably, as a consequence of a 3-h exposure to light of 350-nm wavelength (1.5 × 1015 photons/cm2 sec) followed by a period of 20 h of rest in the dark, the four smaller retinula cells in each ommatidium of the eye of the butterfly Papilio xuthus contain a structure in the peripheral regions of their cytoplasm that resembles a portion of a rhabdom. Evidence for and against the view that this unusual, highly ordered arrangement of membranes represents a trophospongium is presented. In view of the fact that the structure in question only occurred at the same time when rhabdomeres were in a process of disintegration or reformation, the authors conclude that the structure in question is involved in the supply or removal of substances during a period of considerable activity of the retinula cell.
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    Erythropoiesis in the thymus of the spotless starling, Sturnus unicolor (1983)
    Springer
    Cell & tissue research 232 (1983), S. 445-455 
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    ISSN: 1432-0878
    Keywords: Avian thymus ; Intrathymic erythropoiesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Although previously described in other avian species, intrathymic erythropoiesis is a remarkable feature of the thymus of Sturnus unicolor. In discrete stages of the life cycle of this species, erythroblasts and mature erythrocytes occupy large areas of the thymic cortex and cortico-medullary border. Simultaneously, degenerated thymocytes and epithelial-reticular cells occur in the same areas. The relationship between intrathymic erythropoiesis, degeneration of cortical lymphocytes and epithelial-reticular cells, and macrophage activity is discussed and related to a possible functional role of sex hormones in this phenomenon.
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    The in vitro development of the pupal integument and the effects of ecdysteroids in Tenebrio molitor (Insecta, Coleoptera) (1983)
    Springer
    Cell & tissue research 232 (1983), S. 493-511 
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    ISSN: 1432-0878
    Keywords: Ecdysteroids ; Epidermis ; In vitro differentiation ; Tenebrio ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to study the pupal-adult metamorphosis of Tenebrio in vitro, pupal sternites of different ages were cultured in Landureau's medium and their development systematically observed by electron microscopy. In hormone-free medium, explants taken from young pupae do not secrete pupal postecdysial cuticle in vitro, and the epidermis spontaneously detaches from the pupal cuticle. On the contrary, explants taken from pharate adults continue to secrete adult preecdysial cuticle in vitro, and the epidermis never detaches from the cuticle. Ecdysterone in physiological concentrations (0.2 to 4 μg/ml) induces the secretion of a new cuticle in explants from young pupae but the epidermis remains undifferentiated. Ecdysone is necessary for the induction of some adult differentiation. Moreover, the quality of the cuticle secreted in vitro is increased by the addition of 2% foetal calf serum; the best results have thus far been obtained in a medium containing 0.2 μg/ml ecdysone, 1 μg/ml ecdysterone, and 2% foetal calf serum.
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    URL: http://dx.doi.org/10.1007/BF00216424
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    Ciliary epithelia of the mammalian eye in cultured explants (1983)
    Springer
    Cell & tissue research 233 (1983), S. 629-638 
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    ISSN: 1432-0878
    Keywords: Ciliary process ; Cultured explant ; Epithelial cells ; Ultrastructure ; Bovine and rabbit eyes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural characteristics of ciliary epithelium from bovine, pigmented rabbit, and fetal albino rabbit were studied in cultured explants. The tips of ciliary processes were cultured in plastic dishes with Dulbecco Modified Eagle Medium (DMEM) containing 5% fetal bovine serum. More than half of the expiants adhered to the plastic culture dish, and epithelial cells spread as monolayers within a few days. Initially the explant contains two layers, the outer (nonpigmented cells) and the inner (pigmented cells). Later the explant exhibits three layers: 1) outermost lightly pigmented flattened cells, 2) an outer layer of nonpigmented cells, and 3) an inner layer of densely pigmented cuboidal cells. The cells of the outermost layer are continuous with the cells of the inner layer. A narrow space lies between the outermost layer and the outer layer. The columnar cells in the outer layer contain well developed organelles but no pigment granules; they possess a basement membrane, lateral interdigitations, and junctional complexes near their apices. Numerous focal junctions and some ciliary channel-like structures were detected between the columnar cells of the outer layer and the cuboidal cells of the inner layer. The cuboidal cells of the inner layer are filled with pigment granules. These observations suggest that the columnar cells of the outer layer are nonpigmented epithelium, the cuboidal cells of the inner layer are pigmented epithelium, and the flatened cells in the outermost layer are derived from pigmented epithelium.
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    URL: http://dx.doi.org/10.1007/BF00212230
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    Ultrastructural observations on the formation of follicles in the human fetal thyroid (1983)
    Springer
    Cell & tissue research 233 (1983), S. 693-698 
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    ISSN: 1432-0878
    Keywords: Thyroid gland ; Human fetus ; Follicles ; Ultrastructure ; Differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thyroid glands from 40 human fetuses ranging from 30 to 175 mm in length were examined by electron microscopy. At the 30 mm stage, the cells are arranged in cords or clusters and contain numerous free ribosomes. The rough-surfaced endoplasmic reticulum (RER) is poorly developed and the Golgi complex consists of saccules, smooth and coated vesicles. Mitochondria, microfilaments, glycogen particles, occasional lysosome-like structures, and single cilia are observed. At sites of incipient follicle formation, intercellular clefts containing interdigitating microvilli, delimited by junctional complexes, are evident. In addition, the apical region of some cells contains vacuoles. At the 50-mm stage, intercellular clefts are more apparent, some of them organized into small follicles through the enlargement of the lumen, the incorporation of additional cells, and the formation of a basal lamina. With increasing gestational age, more follicles are established. The lumina vary from round to clover-leaf shaped and have an electron-dense content. Cisternae of RER are dilated and contain flocculent material. The Golgi complex is more extensive, and lysosome-like structures are more numerous. By the 100-mm stage, the follicular cells appear morphologically well differentiated. The results demonstrate an extracellular origin of the follicular lumen in the human fetal thyroid.
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    URL: http://dx.doi.org/10.1007/BF00212236
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    The ultrastructure of oesophageal striated muscle in the guinea-pig and marmoset (1983)
    Springer
    Cell & tissue research 234 (1983), S. 365-376 
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    ISSN: 1432-0878
    Keywords: Oesophageal striated muscle ; Ultrastructure ; Guinea-pig, marmoset
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural characteristics of oesophageal striated muscle from guinea-pig and marmoset have been examined using transmission electron microscopy and compared with ultrastructural features of skeletal muscle. The findings show that, although similar to skeletal muscle, oesophageal striated muscle exhibits important differences in the arrangement of its muscle fibres and their motor innervation. It was also found impossible to classify oesophageal striated muscle according to the usual ultrastructural criteria since its motor endplates bore a greater resemblance to those of intrafusal skeletal muscle fibres. The consideration of these differences in conjunction with characteristics revealed elsewhere by other techniques confirms the unique nature of oesophageal striated muscle.
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    URL: http://dx.doi.org/10.1007/BF00213774
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    Ultrastructure of catecholamine-containing axons in the intestine of the domestic fowl (1983)
    Springer
    Cell & tissue research 234 (1983), S. 411-425 
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    ISSN: 1432-0878
    Keywords: Intestines (chicken) ; Innervation ; Catecholamines ; Adrenergic fibres ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Axons in the duodenum, ileum and rectum of the domestic fowl were identified as catecholamine-containing (CA) on the basis of positive reactivity following chromaffin fixation for electron microscopy. CA-axons in association with blood vessels in all regions of the intestine and in non-vascular sites in the small intestine had a ‘ typical’ adrenergic appearance, in that they contained many small granular vesicles (SGV) and variable numbers of large granular vesicles (LGV). In the rectum the non-vascular CA-axon profiles were atypical, in that there were many elongated LGV and few SGV, and the chromaffin reactivity was weak. The nerve profiles in the rectum were dramatically reduced following 6-hydroxydopamine and reserpine treatment and were absent in rectum cultured in the absence of extrinsic ganglia. It was concluded that the profiles, in spite of their low chromaffin reactivity, truely represent CA-axons. The possibility was raised that the atypical morphology and reduced chromaffin reactivity is due to the presence of adrenaline.
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    Ultrastructural identification of corticotropes of the fetal rat (1983)
    Springer
    Cell & tissue research 234 (1983), S. 427-437 
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    ISSN: 1432-0878
    Keywords: Corticotropes ; Rat fetus ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Corticotropes of rat fetuses aged 16, 18 and 21 days were localized by the indirect antibody-enzyme method on semithin sections of the pituitary. The development of the ultrastructure of these cells was observed on consecutive ultrathin sections. In comparison with previous data our present results show that identification of a fetal cell type cannot be based entirely on morphological criteria. The structural peculiarities of corticotropes obtained from studies in vivo are compared with those observed in cells maintained in vitro.
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    Ultrastructure of the reactivated corpus luteum after embryonic diapause in the marsupial, Macropus rufogriseus banksianus (1983)
    Springer
    Cell & tissue research 228 (1983), S. 61-74 
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    ISSN: 1432-0878
    Keywords: Marsupial ; Ultrastructure ; Corpus luteum ; Granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary During embryonic diapause in the red-necked wallaby, M. r. banksianus, both the corpus luteum and uterine blastocyst remain dormant, and are reactivated following removal of the suckling pouch young (RPY). The morphology of dormant and reactivated corpora lutea has been studied throughout the 26.5 days of delayed gestation. Corpora lutea at 0, 2 1/2, 4, 9, 14, 21 and 25 days after RPY were fixed by perfusion. From day 4 to day 14 after RPY there was a progressive increase in the amount of smooth endoplasmic reticulum and the numbers of mitochondria. However there was a decrease in mitochondrial size from 1–2 μm in diameter (0 days after RPY) to 0.5–1 μm (14 days after RPY). Densely-staining granules (approximately 0.2 μm in diameter) were first observed in the luteal cells at 4 days after RPY. The maximum density of granules was observed at 21 days after RPY. Shortly before birth (25 days after RPY) the number of secretory granules had significantly decreased and the features of cellular regression were evident. As with the eutherian mammals, the wallaby luteal cells have all the structural organelles associated with steroid hormone production. The numbers of densely-staining granules are greatest at 21 days after RPY and may reflect the luteal progesterone content since similar granules in the sheep and cow have been shown to be associated with elevated levels of progesterone.
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    URL: http://dx.doi.org/10.1007/BF00206265
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    Circadian variations in pinealocytes of the Chinese hamster, Cricetulus griseus (1983)
    Springer
    Cell & tissue research 228 (1983), S. 231-244 
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    ISSN: 1432-0878
    Keywords: Pineal gland ; Circadian rhythm ; Synaptic ribbon ; Ultrastructure ; Chinese hamster (Cricetulus griseus)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Circadian morphological variations of pinealocytes in the superficial pineal of the Chinese hamster (Cricetulus griseus) were studied using quantitative electron-microscopic techniques. The volume of the nucleus and cytoplasm of pinealocytes exhibited similar circadian variations, with the maximum around the middle of the light period and the minimum during the first half of the dark period. Synaptic ribbons in pinealocytes were classified into three groups, type-1, −2 and −3 synaptic ribbons, which appeared as rods, round or irregular bodies and ring-shaped structures, respectively; a synaptic ribbon index was determined for the respective types. The synaptic ribbon index was expressed as the number of synaptic ribbons in the pinealocyte profile representing the cell size. The type-1 synaptic ribbon index, which was smallest during the second half of the light period, was increased during the dark period. The length of straight or slightly curved rods showed a 24-h change similar to that of the type-1 synaptic ribbon index; the length of the rods was maximal during the first half of the dark period and minimal at the end of the light period. There was no apparent circadian variation in the type-2 synaptic ribbon index. The type-3 synaptic ribbon index was higher during the light period than during the dark period; the index attained zero 3h after the onset of darkness and, thereafter, increased gradually.
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    URL: http://dx.doi.org/10.1007/BF00204875
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    Structure of the non-lymphoid cells during the postnatal development of the rat lymph nodes (1983)
    Springer
    Cell & tissue research 229 (1983), S. 219-232 
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    ISSN: 1432-0878
    Keywords: Lymph nodes ; Postnatal development ; Fibroblastic reticulum cells ; Interdigitating cells ; Deep cortex units ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This study describes the postnatal development of the nonlymphoid cells with special reference to the fibroblastic reticulum cells (FRCs) and interdigitating cells (IDCs). The first lymphocytes of the neonatal lymph nodes are located in the developing deep cortex units (DCUs) identified by the Gomori's technique for reticulin fibres. Ultrastructural studies demonstrate that FRCs form the stroma of the DCUs. By light and electron microscopy, it is demonstrated that FRCs occupy the outer cortex in the following stages of development of the lymph nodes. Thus, FRCs form the stroma of the primary follicles and, later, are transformed in follicular dendritic cells (FDCs) of the germinal centres. Immature or pro-IDCs appear as migrating elements in the deep cortex of lymph nodes of the neonatal rats. The ultrastructure of the pro-IDCs resembles that of the mature IDCs but not that of the phagocytic cells. Pro-IDCs are transformed into mature IDCs whose cytoplasmic expansions contact lymphocytes via tight junctions. Some of these lymphocytes are likely apposed to FRCs of the DCUs. No cells containing Birbeck granules were found in the parenchyma of the lymph nodes during the postnatal development. The role of these nonlymphoid cells is discussed with respect to the immunologic function of mammalian lymph nodes.
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    URL: http://dx.doi.org/10.1007/BF00217894
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    Cytodifferentiation of the paraventricular nucleus in the chick embryo (1983)
    Springer
    Cell & tissue research 229 (1983), S. 281-297 
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    ISSN: 1432-0878
    Keywords: Paraventricular nucleus ; Hypothalamus ; Development ; Golgi study ; Ultrastructure ; Chick embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The developmental changes in the cytoarchitecture of the hypothalamic paraventricular nucleus of the chick embryo were studied with particular emphasis on the differentiation of the magnocellular neurons. These cells can be distinguished from the parvocellular elements starting from stages 34–35 (Hamburger and Hamilton 1951) in Golgi-impregnated specimens. At the same stages, electron microscopy reveals dense-core granules, resembling the characteristic elementary granules of the neurosecretory material in the cytoplasm of the larger neurons. In addition, a few immature synapses were observed on these magnocellular perikarya. The present observations suggest that the early onset of neurosecretion in this area may be neurally regulated during early phases of development.
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    URL: http://dx.doi.org/10.1007/BF00214976
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    Structure of the pars distalis in pouch-young tammar wallabies (Macropus eugenii) (1983)
    Springer
    Cell & tissue research 230 (1983), S. 587-603 
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    ISSN: 1432-0878
    Keywords: Pituitary ; Tammar wallaby ; Marsupial ; Neonate ; Ultrastructure ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pars distalis of pouch-young wallabies (Macropus eugenii) aged 1 to 50 days was studied by means of light-microscopic immunohistochemistry and electron microscopy. In the pars distalis of these pouch-young presumptive somatotrops, which constituted up to 70% of the gland, and nongranulated cells were the most numerous cell types. Small numbers (together representing less than 30% of the pars distalis) of immunoreactive mammotrops, thyrotrops, gonadotrops and corticotrops were also found. The presumptive mammotrops, gonadotrops and thyrotrops increased in number and apparent activity between 1 and 50 days postpartum. Presumptive corticotrop cells in 25 to 30 day-old animals were relatively most numerous, and apparently more active than at any other stage of pouch life; these cells decreased in apparent activity and relative number in older animals. The changes in number and activity of cell types in the pars distalis correlated well with major developmental events such as the onset of adrenal activity, the rapid growth phase in the first 100 days postpartum, and the generally low thyroid activity in pouch-young of less than 50 days of age.
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    URL: http://dx.doi.org/10.1007/BF00216203
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    Spermiogenesis in the rainbow trout (Salmo gairdneri) (1983)
    Springer
    Cell & tissue research 233 (1983), S. 265-284 
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    ISSN: 1432-0878
    Keywords: Spermiogenesis ; Rainbow trout ; Ultrastructure ; Spermatids ; Chromatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an ultrastructural study on the spermiogenesis of the rainbow trout (Salmo gairdneri R.) four spermatogenetic stages were identified. In young round spermatids, the nuclear chromatin was first heterogeneous (euchromatin and heterochromatin). Subsequently, it became more homogeneous and started to condense in the form of coarse granules and fibers and then into fibrils associated in ribbon-like elements which eventually partly fused together. During early spermiogenesis, a juxtanuclear vacuole appeared in the area where the nuclear envelope was specialized due to condensation of material between the two envelopes and a slight accumulation of nuclear material. This area was finally located in the anterior part of spermatids and spermatozoa; it probably plays a role during fertilization. A flagellar rootlet appeared early in spermiogenesis; it may play a role in the attachment of the flagellum to the nucleus since it persisted until the centriolar complex was definitively fixed in the implantation fossa. The flagellum did not display a plasma membrane and was first located in the cytoplasm, but when it was later extruded from the cell, it acquired a membrane. The cytoplasm was rich in ribosomes (free or in small groups) but poor in membranous organelles. The few mitochondria polarized around the centriolar complex were finally organized into an annular mid-piece. The spermatids remained connected by intercellular bridges until the end of spermiogenesis. The complexity of trout spermiogenesis is intermediate between that in poecilids and that in carp and pike, which have very simple spermatozoa. The role of the material from the nucleus and the cytoplasm reaching the Sertoli cell in the control of spermatogenesis has been discussed.
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    URL: http://dx.doi.org/10.1007/BF00238295
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    Ultrastructural morphometry of the myocardium of Thunnus alalunga (1983)
    Springer
    Cell & tissue research 233 (1983), S. 427-438 
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    ISSN: 1432-0878
    Keywords: Myocardium ; Thunnus alalunga ; Ultrastructure ; Mitochondria ; Myofibrils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The common ventricle in the heart of the Thunnus alalunga was studied. The ventricular myocardium consists of an outer compact layer and a thick inner spongy layer. The compact layer has slightly larger cells (4–6 μm diameter) than the spongy layer (2.5–5 μm diameter). Ultrastructurally the myocardium displays normal arrangements of myofibrils and mitochondria. The sarcoplasmic reticulum is poorly developed. The intercalated discs are simple with the fascia adherens being the most frequent junctional type observed; occasionally a desmosome was seen. Nexus type junctions are present but are unassociated with the intercalated discs. There are no t-tubules evident but the plasmalemma exhibits numerous caveolae which rarely form couplings with the sarcoplasmic reticulum. A morphometric analysis of the volume percent of mitochondria and myofibrils showed that the myocardial cells in the spongy layer of the heart have a significantly greater volume percentage of mitochondria than the compact layer. No significant differences were found between myocardial regions when the volume percentages of myofibrils were compared. The physiological studies revealed that the albacore tuna has heart rates (120 bpm) and ventricular blood pressures (100 mmHg) that are among the highest reported for fish.
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    The structure and function of the nematocysts of Chironex fleckeri Southcott, 1956 (1983)
    Springer
    Cell & tissue research 233 (1983), S. 563-577 
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    ISSN: 1432-0878
    Keywords: Nematocysts ; Structure ; Ultrastructure ; Function ; Cubozoa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Microbasic p-mastigophores, euryteles of two size groups, holotrichous isorhizas and atrichous isorhizas, comprise the cnidom of Chironex fleckeri, a cubozoan that has been responsible for several human fatalities. In its undischarged state each microbasic mastigophore of C. fleckeri consists of a capsule containing matrix and an inverted tube possessing a smooth-walled butt which is loosely coiled helically and which narrows to form a thread that is tightly coiled helically and markedly pleated. Both butt and thread carry three helices of spines and contain a granular matrix. During discharge, the proximal butt spines form initially a piercing stylet. Granular material from the butt and thread is released prior to the release of capsular material. Each eurytele possesses a tube with a butt composed of three bulbs, the middle bulb bearing long spines. Each holotrichous isorhiza possesses a coiled tube bearing small spines along its length. Each atrichous isorhiza exhibits a tube that is devoid of spines and loosely folded in the undischarged condition. The probable role of each type of nematocyst is inferred from its structure and features that enable the ready separation of the nematocysts of C. fleckeri from those of scyphozoan jellyfish are discussed.
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    Effects of melatonin on synaptic ribbons in pinealocytes of the Chinese hamster, Cricetulus griseus (1983)
    Springer
    Cell & tissue research 233 (1983), S. 59-67 
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    ISSN: 1432-0878
    Keywords: Pineal gland ; Synaptic ribbon ; Melatonin ; Ultrastructure ; Chinese hamster (Cricetulus griseus)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of melatonin on synaptic ribbons (SR) in pinealocytes of the Chinese hamster (Cricetulus griseus) were examined. SR were classified into types 1, 2 and 3, which appear as rods, round or irregular bodies and ring-shaped structures, respectively; a synaptic ribbon index (SR index) was determined for the three types. Administration of two doses of 1.5 mg/kg melatonin at noon and 3 p.m. causes an increase in the type-1 and type-2 SR indices 3 h after the second injection in hamsters kept under alternating light and dark conditions (lights on from 7 a.m. to 7 p.m.). Likewise, in animals that are exposed to extended light for 6 h and receive two doses of melatonin at 7 p.m. and 10 p.m., an increase in the type-1 and type-2 SR indices occurs 3 h after the second injection. The increase in the type-2 SR index induced by melatonin administration to hamsters exposed to extended light is greater than the increase in the type-1 SR index under the same experimental conditions. Type-2 SR index, but not type-1 SR index, increases following bilateral superior cervical ganglionectomy. An increase in type-1 and type-2 SR indices occurs at 6 p.m. in ganglionectomized animals administered two doses of melatonin 6 h (noon) and 3 h (3 p.m.) before the time of sacrifice. No significant change is observed in type-3 SR index in animals subjected to any of the above treatments. The results indicate that exogenous melatonin may act directly on pinealocytes of the Chinese hamster to cause an increase in size and/or number of the type-1 and type-2 SR. Type 3-SR may have a role different from that of type-1 and type-2 SR; type-1 and type-2 SR may be functionally related.
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    A peculiar myofibrillar pattern in the murine muscletendon junction (1983)
    Springer
    Cell & tissue research 233 (1983), S. 227-231 
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    ISSN: 1432-0878
    Keywords: Muscle-tendon junction ; Ultrastructure ; Myofibrillar pattern ; M. flexor digitorum longus ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The muscle-tendon junctions of adult mice show a special arrangement of myofibrils. Essentially, the myofibrils are oriented in an anchor-like manner in the large finger-shaped processes of the muscle fiber, which contain “mitochondrial sacks” (Demmel et al. 1979) in a subsarcolemmal position. Furthermore, the single myofibril frequently branches out into smaller fibrils. It is suggested that due to the three-dimensional arrangement, these processes gain a high rigidity during contraction, thus maintaining their shape and preserving the “mitochondrial sacks”.
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    Ultrastructural and immunohistochemical studies of rat epididymis (1983)
    Springer
    Cell & tissue research 233 (1983), S. 523-537 
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    ISSN: 1432-0878
    Keywords: Epididymis (rat) ; Myosin ; Actin ; Fibronectin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The anatomical distribution of smooth muscle actin, myosin, fibronectin and basement membrane has been investigated immunohistochemically, using the indirect immunofluorescence technique, in the rat epididymis. The findings were correlated with the ultrastructural organization of the organ. Actin was found to be distributed in the stereociliary region of the epithelial principal cells and in the terminal web region. Actin was also visible along the base of the epithelium. Myosin was detected in the terminal web and in the terminal bar regions of the epithelium. The contractile cells showed a strong stain for both proteins. Basement membrane immunoreactivity was distributed along the epithelial basement membrane and around the contractile cells of the wall. In the cauda, between the epithelium and the contractile cell layers, the lamina propria, containing blood vessels and a thin layer of cells, was negative for all antigens investigated. Fibronectin showed a granular distribution around the contractile cells, mainly in the cauda. The ultrastructural study showed only thin (5–6 nm in diameter) filaments in the stereocilia and terminal web region. Thin filaments were also visible in the cytoplasm of the basal cells, thus suggesting a contractile function of this cell type. The heterogeneous appearance of the contractile cells of the wall seemed to support the different contractile pattern of the epididymal regions: caput, corpus and cauda. The cells present in the lamina propria showed cytoplasmic vesicles with dark granules resembling the “A” cell granules of the endocrine pancreas and gut mucosa cells.
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    Cyclophosphamide-induced changes in rodent odontogenesis (1983)
    Springer
    Cell & tissue research 234 (1983), S. 679-689 
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    ISSN: 1432-0878
    Keywords: Odontogenesis ; Rats ; Cyclophosphamide ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cyclophosphamide-induced changes in rodent odontogenesis were investigated by light and electron microscopy in four-day-old Sprague Dawley rats given one injection of 40 mg/kg of body weight of cyclophosphamide and killed at intervals of one hour, one day, one week and two weeks. Incisor and molar teeth were dissected from the animals, fixed in 2.0% glutaraldehyde in 0.1 M sodium cacodylate with 3.4% sucrose, and subsequently some were incubated for alkaline phosphatase reaction, and embedded in Spurr's medium for sectioning at light- and electron-microscopic levels. From three days a cell-sparse zone was created in the pulp in the growing end of the tooth and progressive cellular changes were observed which became more severe in the one-week and two-week specimens. Subodontoblast and adjacent pulpal cells were the most affected showing nuclear changes, damage to, or loss of, organelles, and inclusion bodies. Odontogenic epithelium was less affected and odontoblasts appeared to be unaffected by the drug. A new irregular matrix was laid down in the defect area and seemed to be the product of depolarized odontoblasts. This new matrix showed alkaline phosphatase activity, as did the cells embedded in it, and later it became mineralized. It is speculated that the polarity of odontoblasts might be maintained by an intact subodontoblastic layer; when this is lost the odontoblasts become depolarized and capable of secreting matrix from both ends.
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    URL: http://dx.doi.org/10.1007/BF00218659
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    Structural and functional studies of the adrenal zona glomerulosa in sodium-depleted and sodium-loaded sheep (1983)
    Springer
    Cell & tissue research 229 (1983), S. 515-531 
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    ISSN: 1432-0878
    Keywords: Adrenal zona glomerulosa ; Ultrastructure ; Sodium depletion ; Sodium loading ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of alterations in sodium status upon the morphology of the adrenal zona glomerulosa in sheep have been examined qualitatively and quantitatively, using lightand electron microscopy, and correlated with functionally related biochemical data. With severe sodium depletion induced by parotid-cannula drainage, there was mitotic activity throughout the zona glomerulosa, and glandular cells showed striking ultrastructural changes. These changes particularly affected mitochondria, which were enlarged, rounded and showed replacement of their normal lamelliform cristae by thin elongated cristal elements and bundles of tubular “rod-like” structures. Quantitative morphometric studies showed an increase in the volumes of zona glomerulosa cells, nuclei, mitochondria, smooth and granular endoplasmic reticulum, and Golgi profiles. In contrast, with dietary sodium loading, zona glomerulosa cells appeared shrunken and showed cytoplasmic lipid accumulation; mitochondria and other organelles were not significantly altered. The correlation of the ultrastructural cytological alterations in zona glomerulosa cells in sodium-depleted sheep with raised blood aldosterone levels suggests that such morphologic changes reflect a heightened capacity of these cells for aldosterone biosynthesis and secretion. These changes may also account for the increased sensitivity of the zona glomerulosa to aldosterone-producing stimuli during sodium deficiency.
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    URL: http://dx.doi.org/10.1007/BF00207695
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    The demonstration of close nerve-Purkinje fibre contacts in false tendons of sheep heart (1983)
    Springer
    Cell & tissue research 230 (1983), S. 105-111 
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    ISSN: 1432-0878
    Keywords: Heart ; Purkinje fibre ; Innervation ; Ultrastructure ; Scanning electron microscopy ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An observation of intimate nerve-Purkinje fibre associations in false tendons of sheep heart is reported. Nerve bundles were observed in deep clefts of Purkinje fibres, in channels running between coupled Purkinje cells and embedded within Purkinje cells, as well as in the outer connective tissue sheath. Most nerve terminals in these areas were filled with small clear vesicles and a few large dense-cored vesicles. Only a few axons with many small dense-cored vesicles were observed. Intimate associations (separation, 60 to 90 nm) between the Purkinje cell and nerve varicosity were observed in the deep clefts. Similar close appositions were also present where nerves were embedded in Purkinje cells. In these cases the Purkinje cell enclosing the nerve bundle formed intercellular junctions with its own sarcolemma. Elaborate sarcolemmal folds with multi-vesicular bodies were also frequently observed near nerve bundles and varicosities. The identity of the transmitter is unknown although the nerves forming intimate associations with Purkinje cells have a morphology typical of cholinergic nerves.
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    URL: http://dx.doi.org/10.1007/BF00216031
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    Sensory receptors associated with the stylets and cibarium of the rice brown planthopper, Nilapavarta lugens (1983)
    Springer
    Cell & tissue research 232 (1983), S. 111-119 
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    ISSN: 1432-0878
    Keywords: Homoptera ; Stylets ; Cibarium ; Sensilla ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The stylets of Nilapavarta lugens consist of two maxillae that interlock to form separate food and salivary ducts partially surrounded by two mandibles. The ultrastructure of the sensory innervation of the stylets is described. Each maxilla possesses five neurones which extend to the tip of the stylet. The mandibles also contain five neurones, four of which are paired. The paired neurones comprise a shorter dendrite extending part of the way along the stylet and a longer one extending to the tip. The possible functions of these neurones are discussed. Gustatory receptors are located in the small passageway leading from the food duct to the cibarium. The receptors are in two distinct groups on the epipharyngeal side and one group on the hypopharyngeal side of the food canal. Two to five neurones innervate each receptor which connects to the food canal via a small pore.
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    URL: http://dx.doi.org/10.1007/BF00222377
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    Ultrastructure of synapses with different transmitter-releasing characteristics on motor axon terminals of a crab, Hyas areneas (1983)
    Springer
    Cell & tissue research 231 (1983), S. 103-115 
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    ISSN: 1432-0878
    Keywords: Synapses ; Ultrastructure ; Crustacean ; Neuromuscular synapse ; Synaptic differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Synaptic terminals on branches of an excitatory motor axon in a spider crab (Hyas areneas) were examined by electron microscopy to determine whether differences in size, structure, and number of synapses could be correlated with differences in transmitter release. Terminals releasing relatively large amounts of transmitter during low frequencies of nerve impulses (“high-output” terminals) had larger synapses, more prominent presynaptic dense bodies (active zones), and fewer synapses per unit length than terminals releasing relatively small amounts of transmitter (“low-output” terminals). Neither the difference in synaptic area, nor the quantitative differences in the active zones, were sufficient in themselves to explain the difference in synaptic efficacy, and it is postulated that a non-linear relationship may exist between structural features of the synapse and release of transmitter by a nerve impulse, and that differences other than those apparent from the ultrastructure could be involved. Greater facilitation at low-output terminals with high frequencies of nerve impulses may be due to greater reserves of “immediately available” transmitter, and to recruitment or activation of more individual synaptic contacts.
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    URL: http://dx.doi.org/10.1007/BF00215778
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    Stellate cells as phagocytes of the anuran pars distalis (1983)
    Springer
    Cell & tissue research 231 (1983), S. 143-155 
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    ISSN: 1432-0878
    Keywords: Stellate cell ; Nongranulated cell ; Phagocyte ; Pars distalis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When the stellate cells (nongranulated cells) from dissociated-cell preparations of the anuran pars distalis were examined, they were seen to contain debris within phagocytic vacuoles (phagosomes). These phagosomes were variable; some contained granules from secretory cells while others were similar to lipid-like bodies and myelin figures. In situ partes distales from frogs were examined at the breeding season. The tissues were divided into lobules that were bounded by processes of stellate cells located between the secretory cells. Processes of stellate cells in the interior of a lobule interdigitate with processes extending inward from the stellate cells forming the border of the lobule. When these processes come together, a small cavity is formed. In many of the intact frogs the spaces between the stellate and secretory cells were greatly enlarged. At this particular time the processes of the stellate cells were attenuated and enclosed secretory granules that were also present as debris in these dilated, intercellular spaces. Within the cytoplasm of these stellate cells were not only phagosomes containing secretory granules but also organelles that appeared to be lipid bodies and lysosomes. Thus, the stellate cells of the pars distalis function in vivo, as well as in vitro, as phagocytes. In addition, macrophage-like cells moving from the blood may form another component of this system of phagocytes.
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    URL: http://dx.doi.org/10.1007/BF00215782
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    Freeze-fracture study of the turtle lung (1983)
    Springer
    Cell & tissue research 231 (1983), S. 157-172 
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    ISSN: 1432-0878
    Keywords: Lung ; Turtle, Pseudemys scripta ; Intercellular junctions ; Freeze-fracture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The air-blood barrier in the lung of the turtle Pseudemys scripta was studied by means of freeze-fracture replicas in an attempt to give a detailed account on the structural organization of the intercellular junctions. Between the pneumocytes, zonulae occludentes containing 4–19 strands in the apico-basal direction are present; they are considered to be physiologically very tight. In the endothelium, fasciae occludentes, i.e., discontinuous occluding junctions can be found, composed of up to 4 strands. These junctions are regarded to be very leaky. The findings are discussed in relation to recent physiological results, suggesting that in comparison with ‘dry’ mammalian lungs, the turtle lung is a rather wet lung based on its much larger transcapillary fluid filtration into the interstitium. In addition, small maculae communicantes are demonstrated between the pneumocytes; they possibly serve for metabolic coupling.
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    URL: http://dx.doi.org/10.1007/BF00215783
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    Correlating the initiation of virus replication with a specific pupal developmental phase of an ichneumonid parasitoid (1983)
    Springer
    Cell & tissue research 231 (1983), S. 387-398 
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    ISSN: 1432-0878
    Keywords: Parasitoid ; Virus ; Pupa ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphogenesis of virus particles associated with the calyx region of the lateral oviduct of the ichneumonid parasitoid Campoletis sonorensis is initiated during a specific phase of pupal development. The extent of body pigmentation proved to be the most reliable visual marker for correlation of induction of virus replication with particular phases of pupal development. Parasitoids removed from their pupal cases at 15 and 16 days after egg deposition were categorized into one of four developmental groups based on the degree of pigmentation. Viruses were not evident in the calyx cells of pupae representing the intial developmental stage, however, in all subsequent stages the concentration of particles gradually increased as development progressed. Observations of freeze-fractured tissue support previous suppositions that the viruses bud through the nuclear envelope following synthesis de novo within the nucleus.
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    URL: http://dx.doi.org/10.1007/BF00222189
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    Structural studies of the adrenal zona glomerulosa and renal juxtaglomerular apparatus in pregnant sheep (1983)
    Springer
    Cell & tissue research 232 (1983), S. 177-187 
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    ISSN: 1432-0878
    Keywords: Pregnancy ; Adrenal zona glomerulosa ; Juxtaglomerular apparatus ; Ultrastructure ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural changes in the adrenal zona glomerulosa and renal juxtaglomerular apparatus have been examined during normal pregnancy in sheep. As pregnancy progressed, increasing numbers of cells in the adrenal zona glomerulosa displayed mitochondria with straight tubular “rod-like” structures replacing their normal lamelliform cristae; groups of cells showing these mitochondrial changes were predominantly located in the middle and superficial regions of the zona glomerulosa, but at all stages remained interspersed with cells with apparently normal mitochondria. In the same animals, the renal juxtaglomerular index was raised, reflecting an increase in renin storage, and juxtaglomerular myoepithelioid cells showed increased numbers of cytoplasmic granules, but no apparent increase in granular endoplasmic reticulum and Golgi profiles; there were no distinguishing morphological changes in juxtaglomerular peripolar cells. These findings provide morphologic evidence of stimulation of the adrenal zona glomerulosa in association with increased juxtaglomerular renin storage during pregnancy. The mitochondrial changes observed in an increasing proportion of cells in the zona glomerulosa closely resemble those seen in sodium-depleted animals, and may reflect the altered steroidogenic capacity of the adrenal gland in pregnant sheep. The finding of groups of cells displaying altered mitochondria lying next to cells with normal mitochondria suggests the presence of cells with different sensitivities to stimuli for aldosterone production or may indicate the presence of different cell types in the zona glomerulosa responding to different stimuli.
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    URL: http://dx.doi.org/10.1007/BF00222382
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    Glomerular ultrastructure of the trout, Salmo gairdneri (1983)
    Springer
    Cell & tissue research 230 (1983), S. 205-218 
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    ISSN: 1432-0878
    Keywords: Kidney ; Glomerulus ; Ultrastructure ; Teleosts ; Seawater adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithelial ultrastructure of the glomerulus of fresh- and sea-water adapted rainbow trout, Salmo gairdneri was examined by scanning and transmission electron microscopy after in vivo-perfusion fixation. Adaptation to seawater for a period of up to 9 weeks was not associated with a change in glomerular size, although after one year in seawater both glomeruli and their capsules were significantly smaller than the glomeruli of freshwater adapted fish. In freshwater adapted trout the epithelial ultrastructure conformed to the general vertebrate pattern, with rounded podocytes, well-defined primary processes and interdigitating pedicels. Adaptation to seawater was associated with a marked increase in the frequency of cytoplasmic microprojections. In many glomeruli there was a flattening of the podocytes, broadening of the primary processes, and areas of closely-packed pedicels were common. These observations are discussed in the light of previous studies on the mammalian kidney and the changes of single nephron function known to be associated with adaptation of trout to increased environmental salinities.
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    URL: http://dx.doi.org/10.1007/BF00216040
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    Variation in sperm morphology in the Australian rodent genus, Pseudomys (Muridae) (1983)
    Springer
    Cell & tissue research 229 (1983), S. 611-625 
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    ISSN: 1432-0878
    Keywords: Spermatozoa ; Ultrastructure ; Pseudomys (Muridae, Rodentia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sperm morphology among the various members of the genus Pseudomys showed great interspecific variation. In P. apodemoides, P. desertor, P. fumeus, P. gracilicaudatus, P. hermannsburgensis, P. higginsi and P. nanus the sperm head was bilaterally flattened and possessed three hooks, the length of which varied somewhat between species. The top hook contained nuclear, subacrosomal and acrosomal material, whereas the two lower ventral hooks displayed largely only an extension of the subacrosomal material. Four other species of Pseudomys had no ventral hooks in their sperm head. In P. novaehollandiae there was a single long top hook, whereas in P. pilligaensis it was almost nonexistent. Neither the sperm head of P. delicatulus, nor that of P. shortridgei possessed any hooks; the former became narrower towards the tip, whereas the latter was spatulate in shape. The acrosome covered about two thirds of the nucleus and varied considerably in shape between species. Insertion of the connecting piece of the tail occurred on the lower ventral side of the sperm head in all species with a long top hook but was nearly basal in P. delicatulus and midbasal in P. shortridgei. The ultrastructure of mid and principal pieces was similar among species, but the number of gyres of mitochondria ranged from about 64 to 100.
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    URL: http://dx.doi.org/10.1007/BF00207701
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    An ultrastructural morphometric study of the papillary muscle of the right ventricle of the cat (1983)
    Springer
    Cell & tissue research 230 (1983), S. 543-552 
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    ISSN: 1432-0878
    Keywords: Myocardium ; Ultrastructure ; Myocardial biopsy ; Morphometry ; Papillary muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The papillary muscle of the cat heart's right ventricle has not been studied previously with quantitative ultrastructural techniques despite its wide use for functional studies. This tissue was perfusion-fixed, processed for electron microscopy, and morphometric techniques were used to assess the ultrastructural characteristics of the papillary muscle as well as the working myocardial cells. The results of this study were that 73.5% of the papillary muscle was composed of muscle cells, 9.7% of blood vessels, and the remainder of interstitial connective tissue. In the muscle cell the volume fraction of mitochondria was 17.3%, that of myofibrils was 49.8%, and that of the nucleus was 2.0%. The mitochondria to myofibrils ratio was 0.36 and the surface to volume ratio was 0.309. In a quantitative ultrastructural comparison of perfusion and immersion fixed tissue it was found that significant differences in the volume density of the blood vessel lumen existed between the two groups. In addition, there were significant differences in the volume fraction of mitochondria and nucleus between perfusion-fixed and immersion-fixed muscle cells. A concurrent significant decrease between the two groups was also found for the ratio of mitochondria to myofibrils. The perfusion-fixed tissue can be considered to provide only normal baseline data for the papillary muscle of the right ventricle. These data are important as they can be used in future structure-function studies on normal and pathological heart tissue.
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    URL: http://dx.doi.org/10.1007/BF00216200
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    The role of connective tissue in the maintenance of epithelial differentiation in the adult (1983)
    Springer
    Cell & tissue research 230 (1983), S. 615-630 
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    ISSN: 1432-0878
    Keywords: Epidermis ; Mouth mucosa ; Connective tissue ; Cell differentiation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Specimens of buccal mucosa and ear skin were introduced into the uteri of isologous rats and the animals maintained under estrogen stimulation for ten weeks, whereupon the uteri were removed and processed for light- and electron-microscopic examination. The majority of implants were successful with the epithelium having migrated to replace the adjacent uterine epithelium. Epidermis and oral epithelium growing on its own connective tissue in the uterus showed a normal pattern of histodifferentiation, including the formation of a thickened keratinized surface and appendages such as hair and sebaceous glands. Ultrastructurally, maturation was similar to that of normal tissue. Epidermis growing on uterine connective tissue did not form appendages but the ultrastructural pattern of cytodifferentiation was similar to control tissue. Buccal epithelium on the uterine stroma was markedly altered in its pattern of maturation, the epithelium appearing thinner than usual and showing a pattern of maturation resembling that of non-keratinization. These results suggest that normal histodifferentiation in epidermis and oral epithelium requires the presence of the appropriate connective tissue; in its absence epidermis has an intrinsic capacity for more or less normal cytodifferentiation but this is lacking in the buccal epithelium.
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    URL: http://dx.doi.org/10.1007/BF00216205
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    Ultrastructure and morphometric analysis of preimplantation mouse embryos (1983)
    Springer
    Cell & tissue research 230 (1983), S. 661-670 
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    ISSN: 1432-0878
    Keywords: Preimplantation embryos ; Mouse ; Ultrastructure ; Morphometric analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary During cleavage, both qualitative and quantitative morphologic characters of mouse ova change. Up to the 8-cell stage, the volume density of mitochondria remains nearly the same although it increases during early and late blastocyst stages. While a rise of the volume fraction of granular endoplasmic reticulum is noticed during cleavage, the volume density of agranular endoplasmic reticulum diminishes gradually from the 1-cell stage onwards. An increase in the volume fraction of autophagic vacuoles is found, the maximum being reached in early blastocysts. The volume fraction of crystalloid inclusions slightly increases after the 4-cell stage, but this increase is statistically insignificant. The volume density of filamentous material (plaques) conspicuously decreases in all studied embryos from the beginning of cleavage. Starting with the 2-cell stage, the volume fraction of lipid droplets remains practically unchanged. No differences in volume densities of the Golgi apparatus, multivesicular and residual bodies, and large cytoplasmic vesicles with medium electron-dense content are found between the respective cleavage stages.
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    URL: http://dx.doi.org/10.1007/BF00216209
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    Ultrastructural and functional development of macrophages in the dermal tissue of rat fetuses (1983)
    Springer
    Cell & tissue research 232 (1983), S. 539-552 
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    ISSN: 1432-0878
    Keywords: Fetal macrophages ; Subepidermal mesenchyme (dermal tissue) ; Rat fetus ; Ontogeny ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary After about 12 days of gestation, fetal macrophages begin to appear in the subepidermal mesenchyme of rat fetuses. The macrophages are ultrastructurally characterized by cytoplasmic vacuoles, abundant polyribosomes and long filopodia. Immunocytologically, they possess Fc and complement (C3) receptors on the cell surface and are capable of immune phagocytosis, Latex or carbon phagocytosis, and glass adherence. From 15 days of gestation, lysosomal granules and miropinocytic vesicles gradually develop, together with an enlargement of Golgi complexes, whereas the number of polysomes and the number and size of cytoplasmic vacuoles are gradually reduced when gestation ends. Finally, the macrophages become amoeboid. Non-specific esterase and endogenous peroxidase activities are always absent in these macrophages. In culture experiments with cell suspensions prepared from the mesenchyme, fetal macrophages show a similar maturation process. Autoradiography with 3H-thymidine demonstrates a high proliferative capacity of the macrophages, particularly during the fetal stage.
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    Electron-microscopical study of the operculum in anuran tadpole after extirpation of the right forelimb during metamorphosis (1983)
    Springer
    Cell & tissue research 232 (1983), S. 513-527 
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    ISSN: 1432-0878
    Keywords: Skin ; Operculum ; Fenestration ; Ultrastructure ; Anura ; Metamorphosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The process of histolysis and fenestration of the skin of the prospective opercular perforation region of Rana japonica after extirpation of the right forelimb was observed during metamorphosis by transmission and scanning electron microscopy. Epidermal cells of the belly of the tadpole, including the operculum, are extremely similar in their ultrastructure. Epidermal cells of the prospective opercular perforation region during metamorphosis become thin and vacuolated especially around the nucleus perhaps by autolysis, associated with lysosomal activity. The histolysis and formation of the perforation of the operculum occurs in the complete absence of forelimb. Macrophages containing phagosomes and lymphocytes or other blood cells are almost always found in the intercellular epidermis. Necrotic epidermal cells progressively separate by cleft formation and slough off without cornification.
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    URL: http://dx.doi.org/10.1007/BF00216425
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    Isolation of metabolically active endothelial cells in high yield from bovine cavernous bodies (1983)
    Springer
    Cell & tissue research 232 (1983), S. 579-591 
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    ISSN: 1432-0878
    Keywords: Cavernous bodies ; Endothelial cells ; Respiratory activity ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Work on endothelial cells has been limited by the availability of procedures for obtaining such cells in quantities adequate for direct in vitro analysis. The present paper describes a method for the isolation of endothelial cells from bovine cavernous bodies. A number of cells ranging from 2.5 to 4 × 108 per animal has been obtained. The cells were identified as follows 1) presence of the “Weibel and Palade” bodies in the isolated cells, 2) “cobblestone” appearance of cell cultures, and 3) presence of factor VIII, as demonstrated by immunofluorescence assays. The cell viability at the end of the purification procedure was tested 1) by dye-exclusion tests and 2) by metabolic assays. Features of this preparation are 1) the very high yield of viable endothelial cells, 2) the absence of contamination by fibroblasts and smooth muscle cells and a very low contamination by erythrocytes and 3) the fine dispersion of the isolated cells. These properties allow functional and subcellular fractionation studies on freshly isolated endothelial cells of microvascular origin.
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    Putative sense organs on the palliai tentacles of the limpet, Patella vulgata (L.) (1983)
    Springer
    Cell & tissue research 231 (1983), S. 663-674 
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    ISSN: 1432-0878
    Keywords: Ciliary tuft ; Pallil tentacles ; Patella vulgata ; Sensory ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure and ultrastructure of ciliary tufts on the pallil tentacles of the limpet Patella vulgata (L.) are described. The tip of each tentacle is covered by a dense crown of tufts and additional tufts can be seen scattered evenly across the surface of each tentacle. The cilia are nonmotile and nerve fibres run from the base of the ciliated cells suggesting a sensory function. Comparisons are made with ciliary tufts found in a Pacific species of limpet, Acmaea scutum, and other molluscan sensory structures.
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    URL: http://dx.doi.org/10.1007/BF00218124
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    Ultrastructural immunocytochemical localization of fibronectin in the developing rat lung (1983)
    Springer
    Cell & tissue research 234 (1983), S. 165-177 
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    ISSN: 1432-0878
    Keywords: Fibronectin ; Lung ; Development ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In a previous study changes in the macrodistribution of fibronectin during rat-lung development were examined. Using the peroxidase-antiperoxidase immunocytochemical technique, we have demonstrated the presence of fibronectin in embryonic, neonatal, and adult rat lung at the ultrastructural level. In the embryo, fibronectin is found both in an intra-and extracellular association with isolated pneumoblasts, and in a periodic distribution along the basal lamina. The neonate displays fibronectin in an intracellular association with early type-I cells and on their basal and luminal surfaces, but not in association with type-II cells. Neonatal basal lamina is diffusely labeled by anti-fibronectin antiserum. Fibronectin in adult tissue is found both intracellularly and on the basal and luminal surfaces of type-I cells but not in type-II cells. The basal lamina and interstitial connective tissue are slightly or non-reactive. These observations confirm and extend our initial suggestion that fibronectin is involved in rat-lung development.
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    URL: http://dx.doi.org/10.1007/BF00217410
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    Electron microscopy of extracellular materials during the development of a sea star, Patiria miniata (Echinodermata: Asteroidea) (1983)
    Springer
    Cell & tissue research 234 (1983), S. 193-200 
    Details
    ISSN: 1432-0878
    Keywords: Sea star ; Development ; Cuticle ; Extracellular materials ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of conspicuous extracellular materials during the life history of a sea star (Patiria miniata) is described. The outer surface of the developing sea star is covered by two morphologically different cuticles that appear sequentially during ontogeny. The primary cuticle, which is about 120 nm thick and two-layered, is present from mid-blastula through the end of the larval stage. The secondary cuticle, which is about 1 μm thick and three-layered, first appears on the epidermis of the rudiment region of the larva and, after metamorphosis, covers the entire epidermis of the juvenile and adult stages. During ontogeny, there are only two conspicuous gut cuticles: the first lines the newly invaginated archenteron at the start of the gastrula stage, and the second lines the esophagus during the larval stage. A blastocoelic basal lamina first appears at mid-blastula and persists as subectodermal and subendodermal basal laminae. Ruthenium red-positive granules are detectable between the lateral surfaces of adjacent ectodermal cells during part of the gastrula stage; this transient intercellular material may possibly aid in lateral adhesion between cells.
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    URL: http://dx.doi.org/10.1007/BF00217412
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