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  • Electron microscopy  (152)
  • Springer  (152)
  • 1995-1999  (11)
  • 1980-1984
  • 1975-1979  (141)
  • 1925-1929
  • 1997  (11)
  • 1978  (68)
  • 1977  (73)
Collection
Keywords
Publisher
  • Springer  (152)
Years
  • 1995-1999  (11)
  • 1980-1984
  • 1975-1979  (141)
  • 1925-1929
Year
  • 1
    Electronic Resource
    Electronic Resource
    The morphology of bone mineral crystals (1978)
    Springer
    Calcified tissue international 25 (1978), S. 217-222 
    Details
    ISSN: 1432-0827
    Keywords: Bone mineral ; Electron microscopy ; X-ray diffraction ; Dark field
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Electron microscopical observations of the size and shape of bone mineral crystallites have not been in complete agreement with X-ray diffraction findings. The two prevalent viewpoints consider bone mineral crystals to be either rod, or plate like in habit. There appears to be agreement that the smallest dimension of the crystals is about 5 nm, but there is discrepancy in the reported c-axial lengths. The method of dark field imaging is used to obtain a quantitative measurement of the c-axial length distribution in rabbit, ox and human bone: mean c-axial lengths 32.6 nm, 36.2 nm and 32.4 nm, respectively, show no significant difference at the 5% level to the mean c-axial length measured by X-ray line broadening. Both bright and dark field images strongly suggest that bone mineral has a plate like form. Reasons for past discrepancies are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010772
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  • 2
    Electronic Resource
    Electronic Resource
    Renewing olfactory receptor neurons in goldfish do not require contact with the olfactory bulb to develop normal chemical responsiveness (1997)
    Springer
    Journal of comparative physiology 181 (1997), S. 425-437 
    Details
    ISSN: 1432-1351
    Keywords: Key words Olfactory receptor cells ; Olfactory bulbectomy ; Olfactory axotomy ; Electrophysiology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract This study investigated whether contact with the olfactory bulb was necessary for developing and renewing olfactory receptor neurons (ORNs) to attain normal odorant responsiveness, and whether the anatomical and functional recoveries of the olfactory epithelium were similar in both bulbectomized (BE) and bilaterally axotomized (AX) preparations. In vivo electrophysiological recordings were obtained in response to amino acids, a bile acid [taurolithocholic acid sulfate(TLCS)] and a pheromonal odorant [17α, 20β,-dihydroxy-4-pregnen-3-one (17,20P)] from sexually immature goldfish. Both transmission and scanning electron microscopy indicated that the olfactory epithelium degenerated in BE and AX goldfish. Within 1–2 weeks subsequent to the respective surgeries, responses to high concentrations (〉0.1 mmol · l−1) of the more stimulatory amino acids remained, whereas responses were no longer obtainable to TLCS and 17,20P. At 4 weeks, responses to amino acid stimuli recovered to control levels, while responses to TLCS and 17,20P were minimal. By 7 weeks post bilateral axotomy, the olfactory epithelium recovered to a condition similar to control sensory epithelium; however, the rate of degeneration and proliferation of receptor neurons in BE preparations appeared to remain in balance, thus blocking further recovery of the olfactory epithelium. At 7 weeks post surgery, odorant responses of AX and BE goldfish to TLCS and 17,20P were still recovering.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003590050126
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  • 3
    Electronic Resource
    Electronic Resource
    Sporulation and spore liberation in Aspergillus fumigatus (1977)
    Springer
    Mycopathologia 60 (1977), S. 175-177 
    Details
    ISSN: 1573-0832
    Keywords: Aspergillus fumigatus ; Spore formation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00448412
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  • 4
    Electronic Resource
    Electronic Resource
    An ultrastructural survey of the genus Prototheca with special reference to plastids (1977)
    Springer
    Mycopathologia 61 (1977), S. 117-119 
    Details
    ISSN: 1573-0832
    Keywords: Prototheca ; Colorless alga ; Plastids ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract An ultrastructural investigation of six different species of Prototheca showed that all of them contained starch grains enclosed in double-membrane-bounded structures recognized as plastids. It is concluded that these unicellular species of Prototheca must be considered as non-photosynthetic algae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00443840
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  • 5
    Electronic Resource
    Electronic Resource
    Scots pine needle injuries at subarctic industrial sites (1997)
    Springer
    Trees 11 (1997), S. 378-387 
    Details
    ISSN: 0931-1890
    Keywords: Key words Pinus sylvestris (L.) ; Electron microscopy ; Heavy metals ; Multi-stress-symptoms ; SO2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Injuries to needles of Scots pines (Pinus sylvestris L.) growing in nutrient-poor soils on the Kola Peninsula collected in April 1991 were studied on a gradient of increasing distances (10 – 115 km) from the Monchegorsk nickel smelter, Russia, which emits SO2, Ni and Cu. The condition of the mesophyll cells was quantified from needles of the two latest age classes using a light and an electron microscope. The damage to the ultrastructure consisted of multistress symptoms caused by excess sulphur, heavy metals, frost, acidic precipitation and ozone. Injuries were most commonly manifested in the form of dark, irregularly shaped chloroplasts with protrusions and light thylakoids and plastoglobuli. These symptoms gradually disappeared with increasing distance and decreasing deposition rate. Concentrations of sulphur, copper and nickel decreased towards more distant sites where normal levels of the latter two elements were reached. Sulphur concentrations remained above background throughout the distance gradient. In the closest plots to the smelter area, cell collapse under the stomata and epidermis related to acute SO2 and heavy metal effects was found, whereas further away symptoms were more diverse, pointing towards the effects of ozone, acidic deposition and thereby decreased frost tolerance. The additive multistress symptoms were clearly seen in the area up to 40 km from the smelter where needle Cu concentration was above 110 ppm, Ni concentration above 39 ppm and S concentration above 1343 ppm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004680050099
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of brefeldin-A and monensin on organelle distribution and morphology in the preimplantation mouse embryo (1997)
    Springer
    Development genes and evolution 206 (1997), S. 503-514 
    Details
    ISSN: 1432-041X
    Keywords: Key words Preimplantation mouse embryo ; Brefeldin-A ; Monensin ; Golgi ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The intracellular trafficking of integral membrane and secreted proteins is likely to be a key element involved in the morphogenesis and differentiation of the early mammalian embryo. In this study, we used transmission electron microscopy (TEM) to analyse the effects of brefeldin-A (BFA) and monensin, well known inhibitors of vesicular protein trafficking in somatic cells, on the structure of preimplantation mouse embryos. Both BFA and monensin distinctively altered the morphology of Golgi compartments in the blastomeres of treated morulae. BFA-treated morulae lacked recognizable Golgi complexes but possessed heterogeneous organelle clusters consisting of an abundance of smooth tubular and vesicular membrane compartments in addition to mitochondria, endosomes and lysosomes. Treatment of morulae with monensin was associated with swelling of Golgi compartments in addition to altering the morphology of mitochondria, lysosomes and the plasma membrane. BFA, and to a lesser extent monensin, inhibited cytokinesis as evidenced by the detection of binucleate blastomeres. In addition, BFA induced morulae to decompact. These latter effects have not been reported previously for these agents in mammalian somatic cell lines or other vertebrate or invertebrate embryos. These results provide the first demonstration of the structural effects of BFA and monensin on cells of the early mammalian embryo, some of which are consistent with the known actions of these agents on components of the vesicular protein trafficking system in mammalian somatic cells. This information serves as a foundation for the further use of these agents in studies of vesicular protein trafficking as an agent of preimplantation morphogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050081
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  • 7
    Electronic Resource
    Electronic Resource
    Quantitative morphogenetic investigations on fine structural changes in the optic tectum of the rainbow trout (Salmo gairdneri) during ontogenesis (1978)
    Springer
    Development genes and evolution 184 (1978), S. 83-94 
    Details
    ISSN: 1432-041X
    Keywords: Synaptogenesis ; Electron microscopy ; Visual acuity ; Fish development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The morphogenetic differentiation of synapses of the optic tectum of the rainbow trout was investigated at different stages of development (from hatching to adult) and compared with the improvement in visual discrimination (minimum separable). (1) The main phase of synaptogenesis (increase in number of synapses, length of contact zone and number of vesicles) begins about one week after hatching and continues up to the age of one month, when the larvae start swimming freely. (2) Myelination begins 26 days after hatching and induces the end of the synaptogenesis period. (3) The visual discrimination (minimum separable) of trout larvae improves from 30 degrees of arc on the 10th day after hatching to 1 degree on day 30, then to about 14 to 18 min of arc in the adult. The results are discussed with special reference to previous biochemical investigations on changes in the ganglioside composition of the trout brain during comparable periods of development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848671
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  • 8
    Electronic Resource
    Electronic Resource
    Cellular calcium distribution in fetal bones studied with K-pyroantimonate (1978)
    Springer
    Calcified tissue international 26 (1978), S. 181-190 
    Details
    ISSN: 1432-0827
    Keywords: Cellular calcium ; Electron microscopy ; Osteoblasts ; Chondrocytes ; Mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The calcium distribution in cartilage and bone cells during beginning ossification of fetal mouse long bones was studied after fixation with 2% K-pyroantimonate in 1% osmium. In the developing periosteum, the future osteoblasts showed a sparse cation-antimonate precipitate over the cytoplasm. In young osteoblasts the precipitate was accumulated on the mitochondrial membranes and the plasmalemma. Both organelles were sharply outlined by precipitate in the mature osteoblasts at the onset of mineralization. X-Ray microprobe analysis of these organelles demonstrated the presence of both Sb and Ca. In the extracellular compartment, a collagen-associated precipitate with 50 to 60 nm periodicity appeared during osteoblastic differentiation. During the initial phase of matrix mineralization, a random gross precipitate appeared in the matrix and seemed to be accumulated by osmiophilic matrix vesicles while the collagen fibrils lost their precipitate. Subsequently, during the confluent phase of matrix mineralization, the precipitate rapidly disappeared from the cells, leaving them devoid of precipitate once they were surrounded by mineralized matrix. Similar changes were found in the chondrocytes of the growth plate, but cartilage collagen, unlike osteoid collagen, did not bind precipitate. The results indicate that both osteoblasts and calcifying cartilage cells bind calcium prior to matrix mineralization. Bone collagen has strong pyroantimonate binding capacity, but it is not directly involved with initial stages of matrix mineralization, which starts in close association with matrix vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013254
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  • 9
    Electronic Resource
    Electronic Resource
    The ultrastructure of the extracellular phase of bone as observed in frozen thin sections (1977)
    Springer
    Calcified tissue international 23 (1977), S. 215-223 
    Details
    ISSN: 1432-0827
    Keywords: Amorphous mineral ; Bone ; Electron microscopy ; Ultracryotomy ; Ultramicro-incineration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The fine structure of the extracellular phase of avian medullary bone and embryonic chick femur was examined in thin sections prepared by ultracryotomy and ultramicroincineration. Since contact with solutions was completely avoided, little or no loss or dislocation of mineral constituents could occur. Amorphous bone mineral (ABM) was present in two forms: as 15–30 nm spheres and as a structure-free haze. Removal of all organic material by low temperature ashing left the ABM intact. Crystals were usually associated with the ABM. In newly ossifying regions clusters or nodules of randomly oriented crystals and ABM appeared to coalesce when they reached approximately 1 μm in diameter. In highly calcified regions crystals appeared to be oriented along collagen fibers. ABM did not appear to be associated with collagen. Unmineralized collagen was visible in osteoid after staining with dry OsO4 vapor and it appeared to be diverted around nodules. Structures which resembled matrix vesicles were present. Selected area electron diffraction patterns indicated the presence of hydroxyapatite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02012788
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  • 10
    Electronic Resource
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    The fine structure of decalcified cartilage and bone: A comparison between decalcification procedures performed before and after embedding (1978)
    Springer
    Calcified tissue international 25 (1978), S. 179-190 
    Details
    ISSN: 1432-0827
    Keywords: Decalcification ; Electron microscopy ; Calcified matrices
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The ultrastructure of calcifying cartilage and bone has been examined under the electron microscope after using three different methods of decalcification. The first was carried out before embedding (by soaking specimens in EDTA or formic acid), the second after embedding (by floating ultrathin sections on formic acid), and the third after embedding (by soaking embedded specimens in EDTA or formic acid), and with later re-embedding. The first procedure invariably induces drastic changes in the fine structure of the cells and calcified matrix, probably as a results of the extraction of organic material along with extraction of mineral. The second and third procedures make it possible to preserve ultrastructural details perfectly in both cells and calcified matrix. Of the two, the third procedure is preferable because of its greater simplicity. In areas that are still calcifying, these post-embedding decalcification techniques reveal the presence of crystal-associated, filamentous organic structures which are not recognizable in specimens decalcified before embedding. These structures, which could have a key role in inducing and regulating crystal formation and growth, are less evident in fully calcified areas (but not at their borders). This may partly be due to the loss of glycan components in the matrix during calcification. The most important determinant, however, seems to be the fact that during calcification the components of the matrix, including collagen fibrils, are involved in an aggregation process which reduces the amounts of free chemical groups available for reaction with the stain solution. Because post-embedding decalcification does not disturb this state of aggregation, the stainability of the matrix and the electron microscopic evidence of its components remain very low.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010766
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  • 11
    Electronic Resource
    Electronic Resource
    Ultrastructural study of amelogenesis imperfecta (1977)
    Springer
    Calcified tissue international 24 (1977), S. 191-197 
    Details
    ISSN: 1432-0827
    Keywords: Amelogenesis imperfecta ; Hypocalcification ; Hypoplasia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary An ultrastructural study of teeth with amelogenesis imperfecta revelaed various aspects of microcavities in the enamel surface, which ranged from isolated imprints of ameloblasts corresponding to the mildest lesions at the end of amelogenesis, to pits caused by the death of 20 to 30 ameloblasts at the beginning of amelogenesis. Abnormalities in the shape of the prisms can be observed. Further, crystals are distributed randomly within a prism or at the junction of 2 contiguous prisms while intercrystalline spaces are widened, indicating in various places the lack of a preferred orientation of the crystals. In amelogenesis imperfecta, two different crystalline periods are found: 1 of about 250 Å, the other of about 500 Å and over. The fact that amorphous areas are found among the crystals of enamel may be related to different stages of crystallization. However, it was not possible to find any lattice defect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02223315
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  • 12
    Electronic Resource
    Electronic Resource
    Further observations on the fine structure of cellular cementum from deciduous teeth of pigs (1977)
    Springer
    Calcified tissue international 24 (1977), S. 239-242 
    Details
    ISSN: 1432-0827
    Keywords: Cementum ; Lysis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Examination of microradiographs from the deciduous teeth of pigs revealed large lacunae or radiolucent zones close to the cemento-dentinal junction. Electron microscopic studies of the ground sections showed areas or irregularly shaped zones devoid of mineral and filled with collagen fibers. In the wide unmineralized zones, spherical clusters of crystallites were noted. Several cementum lacunae bordered by a broad rim of unmineralized collagen fibers were noted and some lacunae also contained zones of a moderately electron dense material. This material did not yield a diffraction pattern, while the mineralized part of the cementum gave the diffraction pattern typical of hydroxyapatite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02223322
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  • 13
    Electronic Resource
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    The crystal sheaths from bivalve hinge ligaments (1978)
    Springer
    Calcified tissue international 25 (1978), S. 45-51 
    Details
    ISSN: 1432-0827
    Keywords: CaCO3 ; Amino acids ; Sheaths ; Ligament ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The aragonite crystals in the molluscan bivalve hinge ligament are surrounded by an organic sheath which is distinct from the remainder of the ligament matrix. Methods have been developed to isolate these sheathed crystals from the ligaments ofSpisula solidissima andMercenaria mercenaria employing a papain digestion of the matrix protein. The sheathed crystals fromSpisula have a CaCO3/protein ratio of 11.1 and those fromMercenaria a ratio of 29.6. The sheathed crystals and the empty crystal sheaths have been examined by electron microscopy for structural integrity. The sheath proteins exhibit much smaller proportions of the amino acids glycine and methionine than the hinge ligaments. These are characteristic amino acids of high concentration in the hinge ligaments of both species. The concentrations of acidic and basic amino acids are increased about two fold in the sheaths over those of the ligaments. Otherwise there is little similarity in the amino acid composition of the sheaths in the two species. However, SDS electrophoresis shows the sheaths of both to contain a major protein component with a molecular weight of about 25,000. The sheath protein from theMercenaria ligament contains about 5% carbohydrate and that ofSpisula sheaths less than 1% carbohydrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010750
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  • 14
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    X-ray diffraction and electron microscope study of osteons during calcification (1978)
    Springer
    Calcified tissue international 25 (1978), S. 133-143 
    Details
    ISSN: 1432-0827
    Keywords: Osteon ; X-Ray diffraction ; Electron microscopy ; Calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary To obtain information on the changes in the inorganic bone fraction during calcification, low- and wide-angle X-ray diffraction techniques and electron microscopy have been applied to single osteon samples. The samples were cylindrically shaped and their axes corresponded to the axes of the Haversian canals. The selection was made according to the degree of calcification and the orientation of collagen bundles and inorganic particles. Osteons at both the initial and final stages of calcification were chosen. Arrangements of fiber bundles and inorganic particles in successive lamellae characteristic of three types of osteon were selected, that is, longitudinally structured osteons, transversely structured osteons, and alternately structured osteons. The results indicate that in osteonic lamellar bone there are two types of inorganic particles: (1) granules arranged in linear or needle-shaped entities with maximum width 40–45 Å, which are regularly distributed at the level of the main band of the collagen fibrils where their maximum length reaches the length of the main band itself; that is, about 400 Å; and (2) very long crystallites, with a diameter of 40–45 Å, which grow with their crystallographicc-axis parallel to the collagen fibrils and cover much more than a major collagen period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010762
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  • 15
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    Dorsal-ventral differentiation in Simonsiella and other aspects of its morphology and ultrastructure (1977)
    Springer
    Archives of microbiology 113 (1977), S. 197-204 
    Details
    ISSN: 1432-072X
    Keywords: Gliding bacterium ; Simonsiella ; Oral cavity ; Electron microscopy ; Morphology ; Dorsal-ventral differentiation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The morphology and ultrastructure of the aerobic, Gram-negative multicellular-filamentous bacteria of the genus Simonsiella were investigated by scanning and transmission electron microscopy. The flat, ribbon-shaped, multicellular filaments show dorsal-ventral differentiation with respect to their orientations to solid substrata. The dorsal surface, orientated away from the substrate, is convex and possesses an unstructured capsule. The ventral surface, on which the organisms adhere and glide, is concave and has an extracellular layer with fibrils extending at right angles from the cell wall. The cytoplasm in the ventral region contains a proliferation of intracytoplasmic membranes and few ribosomes in comparison to the cytoplasm in other parts of the cell. Centripetal cell wall formation is asymmetrical and commences preferentially in the ventral region. Quantitative differences in morphology and cytology exist among selected Simonsiella strains. Functional aspects of this dorsalventral differentiation are discussed with respect to the colonization and adherence of Simonsiella to mucosal squamous epithelial cells in its ecological habitat, the oral cavities of warm-blooded vertebrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00492025
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  • 16
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    Isolation of lipopolysaccharides and the effect of Polymyxin B on the outer membrane of Corynebacterium autotrophicum (1978)
    Springer
    Archives of microbiology 118 (1978), S. 67-69 
    Details
    ISSN: 1432-072X
    Keywords: Corynebacterium autotrophicum ; Outer Membrane ; Lipopolysaccharides ; Biochemical analysis ; Polymyxin B ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lipopolysaccharides (LPS) from Corynebacterium autotrophicum were isolated and analyzed. Autotrophically grown cells contained 2–5 mg of partly purified LPS per g dry weight of lyophilized cells. Serological cross reaction with Lipid A antigen of Salmonella minnesota confirmed the presence of LPS in C. autotrophicum. Electron microscopy of negatively stained Polymyxin B-treated cells showed formation of blebs on the Outer Membrane indicating an interaction of Polymyxin B specifically with LPS. Up to now, no Gram-positive organisms are known which contain any LPS. Thus, C. autotrophicum, though giving opposite results when the Gram-staining reaction was applied by several authors, has to be classified into the group of Gram-negative bacteria.
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    URL: http://dx.doi.org/10.1007/BF00406076
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  • 17
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    Characteristics of a cholera phage (1978)
    Springer
    Archives of microbiology 119 (1978), S. 303-304 
    Details
    ISSN: 1432-072X
    Keywords: Vibrio cholera phage group II ; Properties ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The basic physical, chemical and physiological properties of a group II cholera phage belonging to Mukerjee's classification has been described.
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    URL: http://dx.doi.org/10.1007/BF00405410
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  • 18
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    Detection of small cryptic plasmids in Salmonella typhimurium strain LT2 (1978)
    Springer
    Archives of microbiology 119 (1978), S. 87-90 
    Details
    ISSN: 1432-072X
    Keywords: Salmonella typhimurium strain LT2 (ColIb) ; Cryptic plasmids ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Small cryptic plasmids of molecular weights ranging from 1 to 3 Mdal were detected by electron microscopy in Salmonella typhimurium strain LT2 (ColIb). They were divided into different size classes. Two of the cryptic plasmids were transferred simultaneously with ColIb to Escherichia coli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00407933
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  • 19
    Electronic Resource
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    Electron microscopy of the cell wall complex ofMethylomonas albus (1978)
    Springer
    Archives of microbiology 119 (1978), S. 227-229 
    Details
    ISSN: 1432-072X
    Keywords: Cell wall ; Electron microscopy ; Methylomonas albus ; Goblet sub-units
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In surface view, the cell wall complex ofMethylomonas albus possesses a hexagonal pattern of ridges. Thin sections reveal a continuous layer of goblet-shaped elements attached to the outermost surface of the lipopolysaccharide membrane. A possible interpretation of the cell wall complex ofM. albus, based on the fine-structural data is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00964278
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  • 20
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    Electron microscopic investigation of the hydrogen-oxidizing acetate-forming anaerobic bacterium Acetobacterium woodii (1977)
    Springer
    Archives of microbiology 115 (1977), S. 207-213 
    Details
    ISSN: 1432-072X
    Keywords: Acetobacterium woodii ; Hydrogen-oxidizing acetate-forming anaerobe ; Fine structure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Acetobacterium woodii is a Gram-positive anaerobic nonsporeforming bacterium able to grow on H2 and CO2 as sole sources of energy. The product of fermentation is acetic acid. Fine structural analysis showed rod-shaped flagellated cells, and coccoid cells without flagella arranged predominantly in pairs and chains. The cell wall was found to be composed of three layers. The cell surface exhibited a periodic array of particles consisting of subunits. The cytoplasmic membrane showed particles either either in random distribution or in a hexagonal pattern. Intracytoplasmic membranes were rarely observed, whereas inclusion bodies of varying shapes, predominantly in an uncommon disc-shape, could frequently be observed. Their content was dissolved in ultrathin sections indicating hydrophobic nature.
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    URL: http://dx.doi.org/10.1007/BF00406376
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  • 21
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    Isolation and partial characterization of normal and defective bacteriophages of gram-negative hydrogen bacteria (1977)
    Springer
    Archives of microbiology 115 (1977), S. 237-247 
    Details
    ISSN: 1432-072X
    Keywords: Defective lysogeny ; Alcaligenes eutrophus ; Simultaneous isolation technique ; Temperate bacteriophages ; Pseudomonas pseudoflava ; Biological characterization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Widespread defective lysogeny was detected in Alcaligenes eutrophus by electron microscopic analysis of cultures. Mitomycin C treatment of the cultures resulted in the production of defective (inco-) particles. Polysheaths were produced both with and without induction. With the simultaneous isolation technique six phages were isolated for hydrogen-oxidizing strains of the new species Pseudomonas pseudoflava. The phages were able to replicate under autotrophic conditions and were found to have a very restricted host range. Electron microscopic analysis allowed classification into two structural groups. Group I contained phages with contractile tails; group II contained phages with flexible, noncontractile tails. All but one (gb) of the new phages were shown to be temperate by isolation of lysogens and induction with mitomycin C.
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    URL: http://dx.doi.org/10.1007/BF00446448
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  • 22
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    The mitochondrial complex in cryptophyceae (1977)
    Springer
    Archives of microbiology 112 (1977), S. 207-218 
    Details
    ISSN: 1432-072X
    Keywords: Cryptophyceae ; Algae ; Hemiselmis rufescens ; Chroomonas ; Cryptomonas ; Mitochondrial complex ; Cristae ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The unitary nature of the mitochondrion and the characteristic flattened finger-like morphology of the cristae were demonstrated in the Cryptophyceae. Hemiselmis rufescens contained an unbranched vermi-form mitochondrion in contrast to the variously branched complex, comprising an interconnected peripheral and central reticulum, in Chroomonas sp. and strains of Cryptomonas. The systematic value of the shape and distribution of the mitochondria in the examined genera was suggested.
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    URL: http://dx.doi.org/10.1007/BF00429337
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    Effect of carbon dioxide on pigment and membrane content in Synechococcus lividus (1977)
    Springer
    Archives of microbiology 115 (1977), S. 185-198 
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    ISSN: 1432-072X
    Keywords: Synechococcus lividus ; Cyanobacteria ; Carbon dioxide ; Electron microscopy ; Bleaching-regreening
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of carbon dioxide on pigment and membrane content in Synechococcus lividus was studied by depriving cells of CO2 and examining cell populations biochemically and by electron microscopy. After 120 h of CO2 deprivation, S. lividus lost all detectable chlorophyll a and C-phycocyanin. Such bleached cultures were “mustard yellow”, the result of approximately 1.8 times more carotenoid per cell than green control cultures. Although cells from beached cultures appeared morphologically identical to control green cells when examined by light microscopy, electron microscopic examination revealed them to be devoid of detectable thylakoid membrane. Thylakoid membrane could not be recovered by physical isolation or revealed by freeze etching of bleached S. lividus. In addition, inclusion bodies characteristically found in S. lividus were also absent. Reintroduction of CO2 into bleached cultures resulted in a rapid resynthesis of both chlorophyll a and C-phycocyanin. Electron microscopic examination of these regreening cultures revealed that thylakoid membrane was also rapidly resynthesized. Growth of regreened cultures did not occur until there was the synthesis of a full complement of chlorophyll a, C-phycocyanin, and thylakoid membrane. A time course study of the cytological events occurring during bleaching and regreening is presented.
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    Ultrastructure of carotenoid mutant strain R-26 of Rhodopseudomonas sphaeroides (1978)
    Springer
    Archives of microbiology 118 (1978), S. 305-308 
    Details
    ISSN: 1432-072X
    Keywords: Carotenoid mutant strain R-26-Rhodopseudomonas sphaeroides ; Electron microscopy ; Intracellular membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stained thin-sections and freeze-fractured preparations of the carotenoid-less mutant strain R-26 of Rhodopseudomonas sphaeroides grown photosynthetically revealed 2 morphological kinds of intracellular membrane systems- spherical vesicles distributed throughout the cytoplasm and lamellae confined to the periphery of the cell. The lamellar membranes appeared to be large, flattened vesicles.
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    URL: http://dx.doi.org/10.1007/BF00429122
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    Development and ultrastructure of the marine, parasitic oomycete, Lagenisma coscinodisci Drebes (Lagenidiales) (1978)
    Springer
    Archives of microbiology 116 (1978), S. 133-139 
    Details
    ISSN: 1432-072X
    Keywords: Lagenisma ; Coscinodiscus ; Infection ; Endosymbiotic bacteria ; Tip growth ; Wall-less thallus ; Host-parasite interface ; Membranes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lagenisma coscinodisci is diplanetic and has two different cyst stages. The secondary cyst has a uniform cell wall of fibrillar material. It attaches to a Coscinodiscus frustule and germinates with an infection tube. The cyst becomes filled with an enlarging expulsion vacuole. The infection tube penetrates the diatom cell between the cingula. Inside the host cell the fungus grows as an irregularly branched wall-less thallus. In the hyphae apical vesicles are lacking. The infection tube is plugged by wall material. There are no microtubules which might participate in the morphogenesis of the thallus. The plasmalemma of the diatom is pushed inward but not pierced by the fungus. Along the host-parasite interface it lies closely paralled to the Lagenisma plasmalemma which is extremely straight here and measures about 10 nm instead of about 5–6 nm at the surfaces of other stages. The Coscinodiscus plasmalemma disintegrates at about the same time when the cytoplasm breaks down. The fungus allows bacteria to enter the diatom; there are also endosymbiontic bacteria in unattacked cells — The growth mechanisms are discussed and the host-parasite interface is compared with that of other fungi.
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    URL: http://dx.doi.org/10.1007/BF00406028
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    Fine structure of the ordinary lateral line organ (1977)
    Springer
    Cell & tissue research 176 (1977), S. 23-36 
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    ISSN: 1432-0878
    Keywords: Lateral line organ ; Shark (Mustelus manazo) ; Neuromasts ; Cell types ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The lateral line organ of the spotted shark is characterized by its semi-cylindrical shape. Each organ (neuromast) is so closely apposed to the next that the individual neuromasts are almost continuous. The neuromast is composed of receptor cells, supporting cells and mantle cells. The receptor cells bear one kinocilium and up to 40 stereocilia. Bi-directional arrangement of the receptor cells as occurs in teleosts was demonstrated. Afferent and efferent nerve endings were found at the base of the receptor cells. The supporting cells extend from the basal lamina to the free surface. Long microvilli and a cilium-like “ciliary rod” project from the top of each supporting cell. The cell contains relatively few elements of the Golgi apparatus and little rough endoplasmic reticulum, but mitochondria and filaments are abundant. The mantle cell limits the lateral margin of the neuromast. It is distinguished from the supporting cell because of its long crescent-shaped nucleus and scarce, short microvilli. Myelinated nerve fibres are found in the subepithelial connective tissue but not in the epithelium. The fine structure of the shark lateral line organ suggests that this organ is in an intermediated step of evolution between that of lamprey and teleost.
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    URL: http://dx.doi.org/10.1007/BF00220341
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    Effect of dietary cholesterol on the pattern of osmium deposition in the symbiote-containing cells of the pea aphid (1977)
    Springer
    Cell & tissue research 176 (1977), S. 191-203 
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    ISSN: 1432-0878
    Keywords: OsO4 ; Cholesterol ; Symbiotes ; Aphids ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pea aphids left for 48 h in unbuffered osmium tetroxide show heavy staining of many organelles in the symbiote-containing cells (mycetocytes and sheath), embryos and oenocytes very similar to that characteristic of mammalian sterol-synthesizing cells. However, the staining of the pea-aphid cells is, to a large extent, dependent on the presence of cholesterol benzoate, or free cholesterol, in the aphid's diet. In aphids cultured in vitro with 3H mevalonate in the presence of added cholesterol, the incorporation of label into the cholesterol and lanosterol fractions is significantly reduced. If the dietary cholesterol effects a similar inhibition in vivo, the cholesterol-dependent osmium staining could be due to precursors(s) of cholesterol accumulating in the intracellular sites described. There is also osmium staining of large (normally electron-transparent) vacuoles in mycetocytes, gut and fat body, irrespective of dietary cholesterol.
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    URL: http://dx.doi.org/10.1007/BF00229462
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    The ultrastructure and ultracytochemistry of the basement membrane of the Galleria mellonella fat body (1977)
    Springer
    Cell & tissue research 176 (1977), S. 417-429 
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    ISSN: 1432-0878
    Keywords: Fat body ; Galleria mellonella ; Basement membrane ; Ruthenium red staining ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fat body lobes of Galleria mellonella are surrounded by basement membrane — a fine granular layer of connective tissue. This membrane has an affinity for ruthenium red. The results obtained after treatment of the fat body with neuraminidase, hyaluronidase, phospholipase C and proteolytic enzymes suggest that glycoproteins and phospholipoproteins are constituents of this basement membrane. The basement membrane also has the ability to bind concanavalin A-peroxidase, which is associated with the presence of mannoside residues.
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    URL: http://dx.doi.org/10.1007/BF00221798
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    Protamine induced intracellular uptake of horseradish peroxidase and vacuolation in mouse skeletal muscle in vitro (1977)
    Springer
    Cell & tissue research 176 (1977), S. 463-473 
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    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Protamine ; Endocytosis ; Autophagic vacuolation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The uptake in vitro of horseradish peroxidase (HRP) in mouse skeletal muscle was examined by electron microscopy and chemical determination. In muscles exposed to an HRP solution for 60 min at +37°C, HRP infiltrated the basal lamina of muscle fibres and caused an intense labelling of their sarcolemma. In addition HRP was found within the transverse tubules. Exposure to HRP for 30 min at +37°C followed by HRP together with a polycationic protein (protamine) for 30 min at +37°C caused an intracellular vesicular uptake of HRP. Intracellular HRP was found in numerous vesicles, membrane limited bodies and vacuoles. Protamine also induced focal autophagic vacuolation with progressive muscle fibre degeneration. An intracellular HRP uptake or muscle cell vacuolation could not be detected in the absence of protamine or when the incubation temperature was + 4°C. Chemical determination of HRP uptake was in general agreement with the morphological results. The uptake of HRP in the presence of protamine was stimulated at +31°C and blocked at +4°C. The results suggest that in skeletal muscle in vitro intracellular uptake of macromolecules occurs by endocytosis.
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    Electron dense plaques (calcium binding sites) in the plasma membrane of the endocrine cells in rodent pancreatic islets and parathyroid glands (1977)
    Springer
    Cell & tissue research 177 (1977), S. 81-85 
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    ISSN: 1432-0878
    Keywords: Electron dense plaques ; Pancreatic islets ; Parathyroids ; Electron microscopy ; Calcium binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Small electron dense plaques (EDP) were found in the plasma membrane of pancreatic islet A-, B- and D-cells and parathyroid chief cells of mice and gerbils. The identification of the EDP was facilitated by the use of special fixation techniques. The EDP may represent sites of calcium binding in the cell membranes.
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    Microtubules and extracellular microtubule-like structures in the retina of the rainbow trout (1977)
    Springer
    Cell & tissue research 177 (1977), S. 127-140 
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    ISSN: 1432-0878
    Keywords: Microtubules ; Retina ; Electron microscopy ; Rainbow trout
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the retina of the rainbow trout (Salmo gairdneri, Richardson) two types of microtubular structures are demonstrated. Besides the normal type of microtubules (about 200 Å in diameter), occurring in all cell types of the retina, a second type is described which is termed microtubule-like structure (MLS) because of its extracellular localization. These MLS have a diameter of about 250 Å under the same preparative conditions in which the normal microtubules appear 180–200 Å thick. The interspace between the tubules is smaller than between the microtubules. Specific MLS to membrane associations exist, which are analyzed by serial sectioning and tilting procedures. It is suggested that the MLS have their origin at small membranous extrusions of the plasmalemma. These extrusions could contain nucleation sites for the MLS-formation within the extracellular space. It remains unknown which cell type produces the MLS proteins and which factors are responsible for the aggregation of the subunits to intact MLS.
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    Actin-like filaments in the myoid cell of the testis (1977)
    Springer
    Cell & tissue research 177 (1977), S. 221-226 
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    ISSN: 1432-0878
    Keywords: Actin-like filaments ; Myoid cell ; Testis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Microfilaments in the myoid cells of the peritubular tissue in the mouse, swine and human testis bind heavy meromyosin (HMM) and form arrowhead complexes. The periodicity of the arrowhead complexes is about 35 nm. Individual filaments show arrowheads that point in the same direction. Opposing polarity of the HMM-bound filaments is also observed. The microfilaments do not bind HMM in the presence of 10 mM ATP. After treatment with the contraction medium of Hoffmann-Berling, the filaments appear to be undulated. These observations indicate that the microfilaments in the myoid cell are actin-like in nature. A small number of thicker filaments (about 10 nm in diameter) which do not bind HMM is also observed in the cell. Microfibrils which have been reported around the human myoid cell are also found in the swine.
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    A catecholaminergic neuron connecting the first two optic neuropiles (Lamina ganglionaris and Medulla externa) of the crayfish Pacifastacus leniusculus (1977)
    Springer
    Cell & tissue research 182 (1977), S. 287-297 
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    ISSN: 1432-0878
    Keywords: Optic neuropile ; Crustacea ; Catecholamine ; Fluorescence histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The crustacean optic neuropiles, the lamina ganglionaris and especially the medulla externa, show a specific pattern of green fluorescence with the fluorescence histochemical method of Falck-Hillarp. Normally, only the terminals and the cell bodies fluoresce, but in reserpine-treated animals exogenous catecholamines are taken up by the whole adrenergic neuron and are thus visualized as a whole. Incubating crayfish optic neuropiles in dopamine or α-methylnoradrenaline after reserpine treatment demonstrated a tangential neuron connecting the lamina and the medulla externa. The morphology of this tangential neuron differs from the two types of tangential neurons, Tan1 and Tan2, previously characterized with Golgi techniques. The catecholaminergic neuron thus constitutes a third tangential neuron type.
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    Microtubules in myelinated and unmyelinated axons of rat sciatic nerve (1977)
    Springer
    Cell & tissue research 182 (1977), S. 401-407 
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    ISSN: 1432-0878
    Keywords: Microtubules ; Sciatic nerve (rat) ; Tannic acid ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Tannic acid in glutaraldehyde was used to stain microtubules in myelinated and unmyelinated axons of rat sciatic nerve. In the majority of areas the tannic acid failed to penetrate the unmyelinated axons whilst penetrating neighbouring myelinated axons, suggesting a difference in the ability of the two types of nerves to exclude tannic acid. Where tannic acid had penetrated the unmyelinated axons the 13 protofilament substructure and size of the microtubules appeared identical to those seen in the myelinated axons.
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    Tyrosinase positive oculocutaneous albinism in the goldfish, Carassius auratus L., an ultrastructural and biochemical study of the eye (1977)
    Springer
    Cell & tissue research 182 (1977), S. 409-419 
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    ISSN: 1432-0878
    Keywords: Albinism ; Pigment epithelium ; Tyrosinase ; Electron microscopy ; Carassius auratus L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural studies, and cytochemical and biochemical determinations of tyrosinase activity were conducted on the pigment epithelium of albino and xanthic goldfish eyes. In eyes of xanthic goldfish, two types of melanosomes are present, spherical and elongated. Melanized melanosomes are absent in the eyes of the albino goldfish, but elongated lamellar premelanosomes are observed. Internal vesicles are present in both melanosome types in the pigment epithelium of the xanthic goldfish but are absent in premelanosomes of the albino. There are also differences in the distribution of lipid droplets, smooth endoplasmic reticulum and Golgi complexes with the latter two being more abundant in the albino. Tyrosinase was not identified cytochemically; however, the enzyme was demonstrated biochemically in the pigment epithelia of both albino and xanthic goldfish. The enzyme is associated with the particulate and soluble fractions of both types of eyes. Particulate albino tyrosinase may be solubilized by triton X-100 treatment. Tyrosinase inhibitors are present in the particulate fractions of both albino and xanthic goldfish eyes. Thus, in the goldfish, ocular albinism appears to be a multiple defect at the molecular and ultrastructural levels.
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    Neuronal and glial differentiation in reaggregation cultures (1977)
    Springer
    Cell & tissue research 176 (1977), S. 407-416 
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    ISSN: 1432-0878
    Keywords: Chick embryo ; Electron microscopy ; Glial differentiation ; Neuron differentiation ; Reaggregation cultures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Dissociation and reaggregation cultures from different portions of the chick embryo neural tube were made, and the resulting aggregates were fixed for electron microscopy after 1, 5, 8, 14, 16 and 22 days in vitro. All cultures (pure aggregates of telencephalon, optic lobe or neural retina, and combined aggregates made from mixtures of optic lobe plus neural retina or optic lobe plus telencephalon) show a common timing of neuronal and glial morphological differentiation. During the first week in vitro, some cells developed neuronal characteristics in the absence of morphological evidence of glial differentiation. Numerous axonic processes usually formed fascicles with all the fibers running parallel to each other. Axonic growth cones were abundant and a few immature synapses were also present. The second week in culture was characterized by the disappearance of growth cones and the increase in number and morphological maturation of synapses. Morphologically detectable glial differentiation began by the end of this week, and during the third week almost every neuronal element, including the axonic fascicles, became associated with glial cells showing astrocytic features.
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    Ultrastructural and carbohydrate histochemical studies on the differentiation and renewal of mucous cells in the rat gastric fundus (1977)
    Springer
    Cell & tissue research 176 (1977), S. 445-462 
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    ISSN: 1432-0878
    Keywords: Gastric mucous cells ; Differentiation ; 3H-thymidine incorporation ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gastric surface mucous cells (SMC), mucous neck cells (MNC) and their undifferentiated and immature precursors were studied by light and electron microscopic histochemistry. The secretory granules of SMC were smaller, more electron dense and more reactive to PAS and its analogues than those of MNC. Alcian blue demonstrated that the mucus of SMC was acidic and that of MNC was neutral. The periodic acid —thiocarbohydrazide —silver proteinate method revealed the presence of carbohydrates in the Golgi apparatus, condensing vacuoles, secretory granules, apical vesicles and tubules and cell coat. Maturation of SMC during their migration towards the free surface was reflected by an increase in size and number of secretory granules, an increase of RER and microfilaments, and a decrease of microvilli and apical vesicles and tubules. The secretory granules of older SMC were less acidic and possessed a proteinaceous core. Most MNC were fully differentiated, but some immature MNC containing only a few granules were found. Furthermore, undifferentiated cells and intermediates between SMC and MNC were also observed. The presence of both transitional and intermediate forms indicates that both SMC and MNC arise from the same population of undifferentiated cells. Incorporation of 3H-thymidine revealed that undifferentiated cells, isthmic SMC, MNC and intermediate cells are proliferative. No proliferative activity was found in foveolar SMC, parietal, chief, fibrillovesicular or endocrine cells.
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    Regeneration of soleus muscles of rat autografted in toto as studied by electron microscopy (1977)
    Springer
    Cell & tissue research 177 (1977), S. 159-180 
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    ISSN: 1432-0878
    Keywords: Muscle transplantation ; Rat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat soleus muscles were autografted from right to left legs, and regeneration following necrosis of all original myofibres was studied after 7 to 250 days. The best regenerates were from grafts replacing all calf muscles and sutured to the tendon stumps. After 30 days the size of such regenerates was equal to those from minced gastrocnemius muscles: the cross sectional area of muscle tissue was 30% (1.7 mm2) and the number of fibres was 180% (4500) of normal soleus muscles; the fibre diameters were 10 to 40 μm. To increase the number of myoblasts before grafting some muscles were injured by Ringer solution of 70° C and transplanted after 2 days. Nevertheless, this did not influence regeneration. After 7 days clusters of myotubes occurred in the periphery of the muscle. These myotubes originated from myoblasts growing like endothelial cells on the inner face of the persisting basal lamina tubes of necrotic fibres. After 30 days the muscles were vascularized. Fibres formed in a common basal lamina detached and so looked “split”. Satellite cells of new fibres came from undifferentiated cells associated with myotubes, i.e. from myoblasts. After 30 days and more regenerates contained three sorts of fibres. 1. Thin (5 to 20 μm) fibres resembling fetal muscle fibres. They were most prominent after 30 days, and probably not yet innervated. 2. Thin (10 μm) degenerating fibres as in long-time denervated muscles. 3. Thick (more than 30 μm) mature looking fibres which were innervated and revealed end-plates. Half of the grafts studied after 30 and 60 days contained unmyelinated and myelinated axons which had grown along strands of surviving Schwann cells. After 250 days, only two muscles were studied which both lacked innervation. Almost all regenerates contained muscle spindles, which, however, were not innervated. Within the persisting spindle capsules new muscle fibres had been formed from satellite cells of the former intrafusal fibres.
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    Growth characteristics of postnatal rat adrenal medulla in culture (1977)
    Springer
    Cell & tissue research 177 (1977), S. 247-268 
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    ISSN: 1432-0878
    Keywords: Adrenal medulla ; In vitro ; Phase contrast microscopy ; Catecholamine histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Explants and enzyme-dispersed cells of adrenal medulla from 10–12 day old rats were studied in culture for up to 3 weeks. Adrenomedullary chromaffin cells, nerve cells and satellite cells were clearly discernible. The nerve cells were few in number and did not show catecholaminespecific fluorescence. Chromaffin cells stored catecholamines, as judged by the Falck and Hillarp method, in varying amounts decreasing with age of the cultures and the distance from the explants. Exocytosis profiles observed with the electron microscope suggested that cultured chromaffin cells also released catecholamines. Moreover, the cells formed processes and frequently migrated into the outgrowth. After 6 days in culture, the great majority of chromaffin cells stored noradrenaline as revealed by electron microscopy with few adrenaline-storing cells being visible. Granular vesicles (∼ 80–240 nm in diameter) with cores of different electron densities were occasionally present in the same cell suggesting the occurrence of mixtures of primary and secondary amines. Apart from “chromaffin” granules, small clear and densecored vesicles (∼ 40–60 nm) were found both in the somata and cell processes. Chromaffin cells and their processes were often closely apposed and occasionally formed specialized attachment zones. As a whole, chromaffin cells in culture resembled small granule-containing cells in sympathetic ganglia. 0.5 mM dbcAMP prevented dedifferentiation of chromaffin cells as judged by the lack of processes, the size and amount of “chromaffin” granules and the high number of adrenaline-storing cells present after 6 days in culture. NGF caused a striking increase in the number of axons growing out from expiants.
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    Studies on the juxtaglomerular apparatus (1977)
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    Cell & tissue research 177 (1977), S. 291-305 
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    ISSN: 1432-0878
    Keywords: Juxtaglomerular apparatus ; Tupaia ; Gap junctions ; Renin ; Freeze-fracturing ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vascular pole of the juxtaglomerular apparatus in Tupaia belangeri was studied with special reference to the intercellular contacts of the periendothelial cells and the endothelium of the vas afferens. The periendothelial cells of the vascular pole of the glomerulum are connected by numerous gap junctions; and the granulated epithelial cells are suggested to form a functional unit. Probably there is a continuity of this system troughout the entire vascular pole including (1) all granulated cells, (2) all lacis cells, (3) the mesangium cells and (4) the adjacent smooth muscle cells of the vas afferens and vas efferens. Analysis of the endothelial junctions shows a zonular arrangement of tight junctions indicating a rather tight blood-tissue barrier next to the glomerular vascular pole. The ultrastructure of the different cell types of the vas afferens is also described, emphasizing the granulated epithelial cells and their innervation.
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    On the ultrastructure of polypeptide hormone-producing cells in the gut of the ascidian, Ciona intestinalis L. and the Bivalve, Mytilus edulis L. (1977)
    Springer
    Cell & tissue research 177 (1977), S. 407-413 
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    ISSN: 1432-0878
    Keywords: Gut epithelium ; Ciona intestinalis, Mytilus edulis ; Endocrinecells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural evidence has been found for the presence of polypeptide hormone-producing cells in the gut of Ciona intestinalis L. and Mytilus edulis L. which do not appear to have been described before. Due to their localization and ultrastructural characteristics, it is suggested that the cells in Mytilus edulis probably produce an insulin-like substance and that some of these cells in Ciona intestinalis may produce 5-HT (5-Hydroxytryptamine). In each species only one granulated cell type can be observed. The granules, which are electron dense and membrane bound, also show a halo. The average diameter of the granules is 100–200 nm for Ciona and 200–400 nm for Mytilus.
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    Fine structure of the sensilla of Peripatopsis moseleyi (Onychophora) (1977)
    Springer
    Cell & tissue research 177 (1977), S. 539-553 
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    ISSN: 1432-0878
    Keywords: Sensory receptors ; Peripatopsis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Three types of sensilla occurring on the lips and on the antennae of Peripatopsis moseleyi have been investigated by scanning and transmission electron microscopy. On the lips sensory spines can be found which contain numerous cilia originating from bipolar receptor cells. They reach the tip of the spine where the cuticle is modified. The perikarya of the sensory cells, a large supporting cell with a complicated surface and a second type of receptor, form a bud-like structure and are surrounded by a layer of collagen fibrils. The second receptor cell bears apical stereocilia as well as a kinocilium which are directed towards the centre of the animal — thus the cell appears to be turned upside down. The sensilla of the antennae are 1) sensory bristles containing two or three kinds of receptor cells, one of which bears an apical cilium and one kind of supportive cell and 2) sensory bulbs located within furrows consisting of receptor cells with branched cilia and two kinds of supportive cells which are covered by a modified thin cuticle. According to the electron microscopical findings the sensory spines on the lips are presumably chemoreceptors. The sensory bristles on the antennae can be regarded as mechanoreceptors and the sensory bulbs as chemoreceptors.
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    The morphology of the oval nuclei of neonatal Torpedo marmorata (1977)
    Springer
    Cell & tissue research 178 (1977), S. 155-167 
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    ISSN: 1432-0878
    Keywords: Electromotor system ; Oval nucleus ; Synapses, junctions ; Electron microscopy ; Torpedo marmorata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of the oval nucleus of neonatal Torpedo marmorata is described at the light and electron microscopic level of examination. The nucleus is unique relative to other central electromotor centers of electric fish so far described being bilaterally symmetrical, composed of two nerve cell types, and possessing no gap junctions between neurons and their processes. This particular structural plan presents difficulties in accounting for presumed synchronous discharge since it has been strongly argued that electrotonic coupling by means of gap junctions is the primary process by which synchronization is accomplished. Close membrane apposition and dendritic bundling, common features within the nucleus, are discussed as possible alternative structural correlates.
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    URL: http://dx.doi.org/10.1007/BF00219043
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    The rat epithalamus (1977)
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    Cell & tissue research 182 (1977), S. 1-16 
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    ISSN: 1432-0878
    Keywords: Epithalamus (Rat) ; Supraependymal nerves ; Electron microscopy ; Circumventricular organs ; Medial habenular nucleus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Transmission and scanning electron microscopy of the rat epithalamus shows a regional variation in the distribution of Supraependymal nerves (SN) which correlates well with Supraependymal yellow fluorescence reported by Richards et al. (1974). The medial habenular nucleus, the intercommissural and suprahabenular recesses, the habenular commissure and the fibrae periventriculares thalami have the greatest density of SN/100 μm of ependymal surface. The floor of the suprahabenular and intercommissural recesses is covered by non-ciliated ependyma. The significance of these findings is discussed with respect to (1) a direct functional relationship of SN with ependyma, and (2) a possible participation of the non-ciliated ependyma of the suprahabenular and intercommissural recesses in secretory activity whereby the CSF serves as a vehicle for neuroendocrine communication.
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    URL: http://dx.doi.org/10.1007/BF00222050
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    Electron microscopic observations on the elimination of the oocyte through the peritoneal epithelium in the neonatal mouse ovary (1977)
    Springer
    Cell & tissue research 182 (1977), S. 73-79 
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    ISSN: 1432-0878
    Keywords: Ovary ; Oocyte elimination ; Peritoneal epithelium ; Primordial follicle ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Numerous ovarian oocytes of primordial follicles are lost postnatally by their elimination into the peritoneal cavity during days 1–6 in young mice. It is rarely found in animals over 2 weeks old. This phenomenon has been investigated by light and EM techniques. Oocytes that become extruded from the ovary this way appear to pass between the cells of the covering epithelium. The ultrastructural changes that take place during this process are described.
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    URL: http://dx.doi.org/10.1007/BF00222055
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    The effect of fixation conditions on the ultrastructural appearance of gastrin cell granules in the rat gastric pyloric antrum (1977)
    Springer
    Cell & tissue research 176 (1977), S. 251-263 
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    ISSN: 1432-0878
    Keywords: Gastrin cells ; Electron microscopy ; Fixation ; Granule maturation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural appearance of gastrin cell (G cell) granules was studied after different fixation procedures. When the pH of prefixation was varied there was greater preservation of the electron density of granule cores after acidic (pH 5.0 and 6.0) than after neutral or alkaline (pH 7.0 and 8.0) prefixation. Increasing duration of prefixation at pH 7.3 resulted in progressive loss of electron density of the granule core with swelling and occasional rupture of the limiting membrane. In tissues where most granules had been rendered electron lucent by fixation, those granules remaining dense cored were preferentially located close to the Golgi zone. These findings indicate that the electron density of G cell granules is profoundly affected by conditions of fixation, and that immature granules are more resistant to loss of core density than mature granules. They also suggest that the gastrin granule in vivo, like other polypeptide granules, may have a “solid”, osmotically inactive core.
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    URL: http://dx.doi.org/10.1007/BF00229466
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    Ruthenium red staining of the neural lamella of the brain of Galleria mellonella (1977)
    Springer
    Cell & tissue research 176 (1977), S. 275-284 
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    ISSN: 1432-0878
    Keywords: Neural lamella (wax moth) ; Ruthenium red ; Enzyme digestion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The outer surface of the neural lamella, the connective tissue ensheathing the brain, shows the ability to bind ruthenium red in the wax moth larva. Ruthenium red-positive material is sensitive to neuraminidase, hyaluronidase and to some extent to phospholipase C, what suggests that the negative charge on the external surface of the neural lamella depends on the presence of the anionic groups of sialic and hyaluronic acids and phospholipids.
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    URL: http://dx.doi.org/10.1007/BF00229468
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    A freeze-fracture study of tight junctions in the pars convoluta and pars recta of the renal proximal tubule (1978)
    Springer
    Cell & tissue research 186 (1978), S. 121-133 
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    ISSN: 1432-0878
    Keywords: Proximal tubule ; Tight junctions ; Ultrastructure ; Electron microscopy ; Freeze fracturing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of tight junctions of the renal proximal tubule was studied comparing the pars convoluta and pars recta of rat, golden hamster, rabbit, cat, dog and tupaia. Though some interspecies variations were observed, the convoluted portions of the proximal tubules revealed quite uniformly very leaky tight junctions with mainly 1–2 strands. Along the whole proximal tubule of the rabbit kidney including the pars recta only minor differences of the zonulae occludentes were found. By contrast, the tight junctions of the pars recta in other species were much more elaborate, especially in cat and tupaia, having up to 6 strands and an overall depth of more than 150 nm. The implications of these findings are discussed with special regard to the functional differences between the pars convoluta and pars recta of the proximal tubule.
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    URL: http://dx.doi.org/10.1007/BF00219659
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    Ultrastructure of the theca interna of ovarian follicles in sheep (1978)
    Springer
    Cell & tissue research 187 (1978), S. 457-472 
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    ISSN: 1432-0878
    Keywords: Ovarian follicles (sheep) ; Theca interna ; Oestrogen ; Androgen ; Capillaries ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The theca interna of non-atretic ovarian follicles from 2.0 mm in diameter up to the stage shortly following ovulation was studied by light and electron microscopy. In follicles 〈3.0mm in diameter, the theca interna consisted of about 8–12 layers of flattened cells, together with many capillaries and small bundles of collagen. Two main forms of cellular differentiation were seen. These were towards either fibroblast-like cells or presumed steroidogenic cells whose cytoplasm contained large amounts of predominantly smooth tubular endoplasmic reticulum, to which some ribosomes were attached. The majority of cells were of relatively undifferentiated or intermediate structure. In larger follicles up to the early stages of oestrus the theca interna cells became larger and less flattened, and cells rich in tubular endoplasmic reticulum became proportionately more numerous. By 18 h after the onset of oestrus the theca interna was oedematous, and many cells possessed pseudopodia. Many cells also contained numerous lipid droplets, but there were no signs of thecal cell degeneration or death. Shortly after ovulation the basal lamina of the membrana granulosa was incomplete, and it became more difficult to distinguish between theca and granulosa layers. Structural heterogeneity, with two major cell types and cells of intermediate structure, was present at all stages. It was concluded that: (1) the theca interna of 2.0–2.9 mm follicles contained many cells whose structure was compatible with a steroidogenic capacity; (2) changes in the differentiated thecal cells up to the early stages of oestrus were quantitative rather than qualitative, and suggestive of an increased steroidogenic capacity; (3) the accumulation of lipid in many cells of the theca interna by 18 h after the onset of oestrus probably reflected a reduction in steroidogenic activity; and (4) there was no evidence of any structural specialization to facilitate the transport of steroids from the theca interna to the membrana granulosa.
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    URL: http://dx.doi.org/10.1007/BF00229610
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    Local degenerative changes in the drum muscles of piranhas (Serrasalminae, Characidae) (1978)
    Springer
    Cell & tissue research 188 (1978), S. 75-82 
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    ISSN: 1432-0878
    Keywords: Drum muscles ; Piranha ; Degenerative changes ; Fine structure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the posterior drum muscle of the piranha structural alterations are frequently observed. Electron microscopic studies revealed a disordering of the myofibrils in these regions, accompanied by conspicuous changes in the mitochondria. As the degree of disorder increases, the mitochondrial cristae initially swell to form vesicles. Eventually the mitochondria become filled with myelin-like lamellar structures, which in many cases coalesce to form a dense outer wall. A striking concentration of lysosomes into localized masses was also characteristic of these regions.
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    URL: http://dx.doi.org/10.1007/BF00220515
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    Studies on the ultrastructure of the integument of the rotifer Habrotrocha rosa Donner (Aschelminthes) (1978)
    Springer
    Cell & tissue research 189 (1978), S. 167-177 
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    ISSN: 1432-0878
    Keywords: Hypodermis ; Rotifer ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The integument of the rotifer Habrotrocha rosa Donner is provided with pores and formed by an extrasyncytial cuticle and a syncytial hypodermis. The hypodermis peripherally contains 3 layers of dense cytoplasm and borders the cuticle by an asymmetric cell membrane. The wall of the pores is stiffened proximally like an annulus. The pores lead into cytoplasmic invaginations which are surrounded by vesicles. Close to and also beneath the condensed cytoplasmic layers microbodies are found, which are interpreted as microperoxisomes. Subhypodermal layers of muscles are connected with the cytoplasm of the hypodermis by desmosome-like structures.
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    URL: http://dx.doi.org/10.1007/BF00223127
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    Catecholaminergic innervation of muscles in the hindgut of crustaceans (1978)
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    Cell & tissue research 189 (1978), S. 257-266 
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    ISSN: 1432-0878
    Keywords: Neuromuscular junction ; Hindgut ; Crustacea ; Catecholamine ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The crustacean species Pacifastacus leniusculus and Gammarus pulex were investigated by electron microscopy in a search for possible neuromuscular junctions in the hindgut, which has a rich supply of catecholaminergic fibres. True neuromuscular synapses were found in both species between nerve terminals containing dense-core vesicles (80–110 nm in diam.) and muscle fibres. We suggest that the dense-core vesicle terminals contain a catecholamine, and this is supported by ultrahistochemical tests for monoamines. Two types of junctions are found: one in which the nerve terminal is embedded in the muscle cell (both species) and one in which protrusions from the muscle cell meet nerve terminals (Pacifastacus). Gammarus pulex, which has only circular muscles in the hindgut, has only catecholaminergic innervation, whereas Pacifastacus leniusculus has circular and longitudinal muscles both with at least two types of innervation.
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    URL: http://dx.doi.org/10.1007/BF00209275
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    Influence of maternal adrenalectomy on the ultrastructure of the adrenal gland in neonatal rats (1978)
    Springer
    Cell & tissue research 189 (1978), S. 277-286 
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    ISSN: 1432-0878
    Keywords: Maternal adrenalectomy ; Rat ; Influence on the adrenals of newborn animals ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Maternal adrenalectomy at 7 or 14 days of gestation produced increased cell necrosis within zona reticularis cells on the day of birth and at 24 or 48 h after birth. Small remnants or large portions of adrenocortical cells were present within macrophages. In otherwise normal adrenocortical cells, lipid droplets were incorporated within some mitochondria. Autophagocytosis of single mitochondria was observed within adrenocortical cells. Undoubtedly ultrastructural changes represent stimulation of adrenocortical cells in neonatal rats in response to maternal adrenalectomy.
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    URL: http://dx.doi.org/10.1007/BF00209277
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    Structure of occluding junctions in ileal epithelial cells of suckling rats (1978)
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    Cell & tissue research 191 (1978), S. 449-462 
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    ISSN: 1432-0878
    Keywords: Ileum (Rat) ; Occluding junctions ; Freeze-fracture ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two kinds of occluding junctions are found between ileal epithelial cells of suckling rats: apical zonulae occludentes (ZO) and fasciae occludentes (FO) which are associated with the lateral plasma membranes of many epithelial cells. In unfixed preparations, glycerol treatment induces the further proliferation of extensive fasciae occludentes. Both kinds of junction have identical structural elements when visualized in freeze fracture replicas, although the arrangement of these elements differs. Zonulae occludentes consist of networks of branching and anastomosing linear ridges or rows of ∼10 nm particles with 20–30 nm spaces between the rows which form narrow belt-like structures around the apical region of adjacent cells. Fasciae occludentes, on the other hand, consist of similar linear ridges or rows of particles but the junction strands are often discontinuous, open ended and only occasionally intersect with each other. Several different fracture planes through the plasma membrane in the region of the occluding junctions have been observed and these provide further evidence that two components, one from each membrane, fused at the level of the extracellular space, form the junction sealing element. Furthermore, we present evidence which indicates a staggered rather than an in-register arrangement of these two components.
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    URL: http://dx.doi.org/10.1007/BF00219808
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    The ultrastructure of the accessory sex organs of the male rat (1978)
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    Cell & tissue research 192 (1978), S. 39-51 
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    ISSN: 1432-0878
    Keywords: Prostate ; Rat-Anti-Androgens ; Nuclear alterations ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the nuclei of epithelial cells of the dorsal lobe of the rat prostate were studied after administration of three different antiandrogenic compounds. The nucleolus appears to undergo a progressive disorganisation with partial fragmentation and dispersion of its normal components. Different types of intranuclear inclusions were found. The various alterations observed were often encountered within the same section. This may indicate that the nuclear alterations occur in the same compartment of the cell, and represent a dysfunction of integrated biochemical events occurring within this compartment. The findings support a view that the stimulatory secretory effect of androgens is mediated via a ‘secretory center’, located within the nucleolusassociated chromatin. Within this ‘secretory center’, the initial steps of the secretory process, the binding of the DHT receptor complex to DNA is assumed to occur.
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    URL: http://dx.doi.org/10.1007/BF00231021
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    Stereological model system for free cells and base-line data for human peripheral blood-derived small t-lymphocytes (1978)
    Springer
    Cell & tissue research 192 (1978), S. 121-142 
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    ISSN: 1432-0878
    Keywords: T-lymphocytes ; Stereological model system ; Free cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Menschliche, in Nylonwolle gereinigte T-Lymphozyten aus dem peripheren Blut dienten als repräsentatives Untersuchungsobjekt zur Schaffung eines neuen stereologischen Modellsystems für freie, sphärische Zellen. Dieses System erlaubt, die Zelle und die darin enthaltenen Strukturkomponenten auf ultrastruktureller Ebene quantitativ zu charakterisieren.
    Notes: Summary T-lymphocytes derived from human peripheral blood and passed through a nylon-wool column, were employed to develop and test a new Stereological model system for free spherical cells, allowing a quantitative characterization of the cell and its components at the ultrastructural level. Electron micrographs were recorded in a hierarchical manner at three different levels of magnification and subjected to point counting procedures. The resulting parameters were expressed in relation to various reference compartments, both absolute and relative. Results indicated that the average volume of a small, non-activated T-lymphocyte was 103.8 μm3, the nuclear volume 47.5 μm3 and the cytoplasmic volume 55.9 μm3. On the average, the cytoplasm contained 30 mitochondria, 0.7 μm3 RER-cisternae, 0.2 μm3 cisternae and vesicles of the Golgi apparatus and about 231,000 free ribosomes (most of them single). The ratio of eu- to heterochromatin volume was 0.5. The design and application of the Stereological model system are discussed with regard to dynamic studies of a variety of free cells, such as macrophages, neutrophilic granulocytes and various lymphocytes.
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    Neuropeptide Y-immunoreactive intracardiac neurones, granule-containing cells and nerves associated with ganglia and blood vessels in rat and guinea-pig heart (1997)
    Springer
    Cell & tissue research 289 (1997), S. 445-454 
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    ISSN: 1432-0878
    Keywords: Key words: Intracardiac neurones ; Innervation ; Heart ; Neuropeptide Y ; Immunocytochemistry ; Electron microscopy ; Rat (Sprague Dawley) ; Guinea-pig (Dunkin Hartley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Intrinsic neuropeptide Y-containing neurones in rat and guinea-pig hearts were studied at the ultrastructural level by the pre-embedding peroxidase-antiperoxidase immunocytochemical technique. Intracardiac neuronal cell bodies were often weakly or moderately immunostained, and the labelling was usually pronounced in the Golgi complex, multivesicular bodies, some cisterns of granular endoplasmic reticulum and large granular vesicles. Neuropeptide Y-immunoreactive nerve fibres were also observed in association with intracardiac neurones. A subpopulation of neuropeptide Y-immunoreactive granule-containing cells in the rat heart are described for the first time and were very heavily labelled; other granule-containing cells were non-immunoreactive, but were contacted by neuropeptide Y-containing nerves. Preterminal regions of nerve fibres that were located in nerve bundles were only weakly neuropeptide Y-immunoreactive, in contrast to the heavy labelling observed in varicosities that contained many synaptic vesicles. Many neuropeptide Y-immunoreactive nerve fibres were associated with the coronary vasculature and were particularly prominent in the walls of small arteries and arterioles where labelled nerve varicosities were present close to the smooth muscle cells. Immunoreactive nerves were also seen in the myocardium, usually near to capillaries. In axonal varicosities, the central core of large granular vesicles was immunolabelled, and electron-dense immunoreactive material outlined the membranes of small and large clear vesicles. The significance of neuropeptide Y-immunoreactive intracardiac neurones and granule-containing cells and the origin of associated labelled nerve fibres in the heart are discussed.
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    An autoradiographic study of satellite cell differentiation into regenerating myotubes following transplantation of muscles in young rats (1978)
    Springer
    Cell & tissue research 186 (1978), S. 535-540 
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    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Satellite cells ; Regeneration ; Electron microscopy ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Satellite cells were traced autoradiographically during the regeneration of skeletal muscle in young Sprague-Dawley rats. Approximately 31% of the satellite cells in uninjured muscles appeared labelled after three injections of tritiated thymidine; none of the myonuclei were labelled in the same muscles. Four to six days after transplanting the radioactive muscles to non-radioactive littermates, regenerating myotube nuclei in the host appeared labelled. Thus, this study confirms that satellite cells in young rats can differentiate into multinucleated myotubes following muscle injury.
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    URL: http://dx.doi.org/10.1007/BF00224941
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    Endocrine cells in the gut of the ascidian Styela clava (1978)
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    Cell & tissue research 187 (1978), S. 159-165 
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    ISSN: 1432-0878
    Keywords: Endocrine cells ; Ascidian (Styela clava) ; Gut epithelium ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural studies have shown the presence of two types of granulated endocrine cell in the gut of Styela clava. Type I, which occurs in the stomach and intestine contains small irregular granules, each with a distinct halo. Type II, found only in the oesophagus contains larger rounded granules, often with little or no halo. The characteristics of these two cell types are compared with those of endocrine cells found in the digestive tracts of other protochordates and discussed with special reference to the evolution of gastrointestinal endocrine cells in vertebrates.
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    The junctional connections between the cells of the urinary bladder in the rat (1978)
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    Cell & tissue research 187 (1978), S. 439-448 
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    ISSN: 1432-0878
    Keywords: Urinary bladder epithelium (Rat) ; Gap junctions ; Tight junctions ; Electron microscopy ; Freeze-fracturing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The junctional connections between the cells of the urinary bladder epithelium in rat have been studied by freeze-fracturing. Tight junctions and desmosomes are known as structural features of the epithelium. In addition, gap junctions (nexus) have been found to connect the epithelial cells in an irregular distribution pattern. The junction size ranges from few assembled particles up to plaques with irregular forms. This may indicate that the gap junctions are mobile structures. The functional significance of the junctions in comparison with electrophysiological data is discussed.
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    URL: http://dx.doi.org/10.1007/BF00229608
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    The passage of spermatozoa through the vitelline membrane in the domestic fowl, Gallus gallus (1978)
    Springer
    Cell & tissue research 188 (1978), S. 497-508 
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    ISSN: 1432-0878
    Keywords: Fertilization ; Domestic fowl ; Acrosome reaction ; Vitelline membrane ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The developing outer layer of the vitelline membrane of the ovum in the posterior part of the infundibulum of the domestic fowl contains many spermatozoa in nearly parallel orientation with its inner layer. When the acrosomal region of a spermatozoon approaches or contacts the inner layer, promptly undergoes the acrosome reaction. The outer acrosomal membrane and overlying plasma membrane fuse together and the apical region of the acrosome opens, so that the acrosomal contents are released. Meanwhile the spermatozoon remains a time in contact with the surface of the inner layer, and the network of the inner layer just under the tip of the sperm head begins to be dissolved. This dissolution extends downward forming a tunnel, approximately 9 μm in diameter. The spermatozoon then passes through the inner layer obliquely via the central region of the tunnel and arrives at the perivitelline space.
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    URL: http://dx.doi.org/10.1007/BF00219787
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    A study of the fine structure of the pit organ of the common Japanese sea eel Conger myriaster (1978)
    Springer
    Cell & tissue research 189 (1978), S. 375-388 
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    ISSN: 1432-0878
    Keywords: Lateral line organ ; Pit organ ; Sea eel (Conger myriaster) ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the pit organ of the sea eel has been studied by means of electron microscopy. The sensory epithelium of the pit organ consists of sensory cells and supporting cells. The apical surface of the sensory cell is studded with sensory hairs consisting of a kinocilium and stereocilia. The sensory cells are divided into two groups. In one, the kinocilium points dorsally and in the other the kinocilium points ventrally. The total number of sensory cells in one pit organ is about 100, and the ratio of cells with opposite polarity is about 1∶1. On the basis of these structural features, the pit organ is considered to be a mechano-receptor sensitive to the movement of liquid in a dorso-ventral direction. It may also serve as an ion receptor, sensitive to environmental ion concentration. Efferent nerve terminals make rare synaptic contacts on the afferent nerve fiber.
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    URL: http://dx.doi.org/10.1007/BF00209127
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    On the excretory system of the rotifer Habrotrocha rosa donner (1978)
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    Cell & tissue research 189 (1978), S. 515-523 
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    ISSN: 1432-0878
    Keywords: Protonephridium ; Rotifer ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The excretory system of Habrotrocha rosa consists of two protonephridia. From each of them seven tubules lead to a terminal organ, also called cyrtocyte. Its weir basket contains structures which resemble ciliary rootlets. The lumen of the excretory system is bordered by a syncytial layer of cytoplasm. Cells are only found in the upper region of the trunk, where the channel is twisted several times.
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    URL: http://dx.doi.org/10.1007/BF00209137
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    Studies on the ultrastructure of the rotifer Habrotrocha rosa Donner (Aschelminthes) (1978)
    Springer
    Cell & tissue research 189 (1978), S. 525-535 
    Details
    ISSN: 1432-0878
    Keywords: Alimentary system ; Rotifer ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The alimentary system of Habrotrocha rosa is composed of the alimentary channel, five digestive glands and another gland which is in close relation to the intestinal syncytium. After the present investigation, the alimentary channel can be divided into sections which clearly differ from each other, these are: oral cavity, pharynx, oesophagus, mastax, stomach-hose, syncytium of intestine, and terminal intestine.
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    URL: http://dx.doi.org/10.1007/BF00209138
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    Immuno-electron microscopy reveals that the excitotoxin quinolinate is associated with the plasma membrane in human peripheral blood monocytes/macrophages (1997)
    Springer
    Cell & tissue research 290 (1997), S. 633-639 
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    ISSN: 1432-0878
    Keywords: Key words: Quinolinic acid ; Interferon-γ ; Kynurenine ; Electron microscopy ; Immunocytochemistry ; Excitotoxicity ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract.  Quinolinate (QUIN), a tryptophan-derived excitotoxin, was localized ultrastructurally in human peripheral blood monocytes/macrophages (MØ) by immuno-electron microscopy. A combined carbodiimide/glutaraldehyde/paraformaldehyde-based fixation procedure was developed for optimal retention of QUIN in the cell as well as minimal loss of ultrastructure; a silver-enhanced colloidal gold detection system was used for electron-microscopic analysis. Gold particles representing QUIN immunoreactivity were associated with the inner side of the plasma membrane in normal MØ. The number of gold particles increased significantly when QUIN levels were elevated by treatment with its precursor kynurenine, but location of the gold particles remained essentially the same under this condition. Treatment with interferon-γ increased the number of Golgi bodies, vacuoles and pseudopodia, reflecting the activated state of the cell. Significantly increased numbers of gold particles representing QUIN were detectable in approximately the same location as in the case of kynurenine treatment. Combined treatment with kynurenine and interferon-γ maximally increased the number of gold particles at the periphery of the cell. The pseudopodia were intensely stained with gold particles, while they were not detectable in the inner part of the cytoplasm or in any other organelle even under this activated condition. The significance of the specific location of QUIN revealed in the present study and its relation to the release and subsequent actions of QUIN are discussed.
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    URL: http://dx.doi.org/10.1007/s004410050969
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    Synaptic exocytosis of dense-core vesicles in blue crab (Callinectes sapidus) stomach muscles (1997)
    Springer
    Cell & tissue research 289 (1997), S. 517-526 
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    ISSN: 1432-0878
    Keywords: Key words: Neuromuscular junction ; Synaptic vesicles ; Vesicle fusion ; Electron microscopy ; Callinectes sapidus (Crustacea)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Neuromuscular terminals of a single motoneuron to four muscles (CPV7a, GM5a, CV2, and CV3) in the stomach of the blue crab Callinectes sapidus showed structural evidence for the exocytotic release of dense-core vesicles exclusively at synapses. The primary evidence was the appearance of dense cores in the synaptic cleft, accompanied by indentations of the presynaptic or postsynaptic membrane. In their simplest form, these consisted of an omega-shaped figure of the presynaptic membrane enclosing one dense core, denoting release of a single dense-core vesicle. A larger indentation of the presynaptic membrane enclosing several dense cores denoted multiple release. A more complex form of multiple release was where the presynaptic membrane was normal, but the postsynaptic membrane elaborated into a sac projecting into the granular sarcoplasm and filled with dense cores. The postsynaptic sac in some instances was compressed into a thin, fingerlike extension, which lacked dense cores and, at its distal end, separated into small cisternae, suggesting a mechanism for membrane recycling. Profiles depicting single and multiple releases of dense-core vesicles were found more frequently at neuromuscular terminals that release relatively large amounts of transmitter with a single stimulus, such as CV2 and CV3, compared to those releasing smaller amounts, such as CPV7a and GM5a. The disparity in release sites among the four muscles of this single motor unit and the fact that many of the multiple-release figures were closely adjacent to the active zones for transmitter release suggest a possible modulatory role for dense-core vesicles in synaptic transmission. Such modulation may be long lasting, as implied by the postsynaptic sacs, which may permit prolonged release of the contents of their dense cores into the synaptic cleft. This is in keeping with the functional role of these stomach muscles, which is to be continuously active for long periods of time.
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    URL: http://dx.doi.org/10.1007/s004410050897
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    Nerve-purkinje fiber relationship in the moderator band of bovine and caprine heart (1978)
    Springer
    Cell & tissue research 188 (1978), S. 11-18 
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    ISSN: 1432-0878
    Keywords: Purkinje fibers (Ox, goat) ; Axons ; Nerve endings ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The moderator band in the heart of the ox and goat contains bundles of Purkinje fibers and nerve fibers separated by connective tissue. The axons are mostly unmyelinated and embedded in the cytoplasm of Schwann cells. Small bundles of axons run close to the Purkinje fibers. The axons dilate into varicosities 0.5 to 1.6 μ in diameter (mean 0.95 μ), containing three types of vesicles: 1) agranular vesicles with a diameter of 400–500 Å, 2) large dense-cored vesicles with a diameter of 800–1200 Å, 3) small dense-cored vesicles with a diameter of 500 Å. Most varicosities contain agranular vesicles together with a few large dense-cored vesicles. The gap between the varicosities and the nearest Purkinje fiber is unusually wide and normally varies between 0.3 μ and 0.8 μ. No intimate nerve-Purkinje fiber contacts, with a cleft of 200 Å, were observed.
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    URL: http://dx.doi.org/10.1007/BF00220511
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    On T-tubule openings at the sarcolemma of white fast-twitch muscle fibres in fish and frog (1978)
    Springer
    Cell & tissue research 188 (1978), S. 265-272 
    Details
    ISSN: 1432-0878
    Keywords: Muscles ; T-system ; Fish ; Frog ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In “white” muscle fibres of a teleost fish T-tubule openings may occur regularly at all Z-disc levels between adjacent peripheral myofibrils, the T-tubule openings thus occurring at a density of ca. 0.9 μm-2. In frog “white” fibres, T-tubule openings are infrequently seen in material fixed like the fish material. In material prepared according to the albumin method of Gray (1975, 1976 a, b) which renders the muscle fibres swollen, straight tubules or sometimes chains of vesicles instead are seen opening at the sarcolemmal surface. Such tubules occur at a higher density than expected from experiments with local activation of contraction. Lability and dynamics within the T-system normally and during fixation are discussed.
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    URL: http://dx.doi.org/10.1007/BF00222636
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    Parenchymal fine structure of the subfornical organ in the Japanese quail, Coturnix coturnix japonica (1978)
    Springer
    Cell & tissue research 191 (1978), S. 405-419 
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    ISSN: 1432-0878
    Keywords: Subfornical organ ; Japanese quail, Coturnix coturnix japonica ; Monoaminergic innervation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The parenchyma of the subfornical organ (SFO) of the Japanese quail was studied by light and electron microscopy. The SFO consists of ependymal, intermediate, and basal (perimeningeal) layers. In the intermediate layer, neurons, glial cells, and their processes are found. Axons containing dense core granules approximately 80 nm in diameter are numerous, some of which make synaptic contact with the neuronal perikarya or dendrites. Synaptic vesicles in some axons contain a dense dot in the interior after treatment with 5-hydroxydopamine. The activity of the SFO, which is probably concerned with elicitation of drinking by angiotensin II, may be regulated at least partly by afferent monoaminergic axons. Capillaries with a non-fenestrated endothelium are occasionally found in the parenchyma. The basal layer is occupied by glial processes abutting on the digitating layer of perivascular connective tissue of meningeal vessels. The endothelium of these vessels is occasionally fenestrated. Trypan blue injected systemically accumulated in the SFO, but not in the deeper areas of the brain. The absence of a blood-brain barrier is suggested in the SFO.
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    URL: http://dx.doi.org/10.1007/BF00219805
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    Sequential differentiation of intestinal endocrine cells in the fetal mouse (1978)
    Springer
    Cell & tissue research 192 (1978), S. 267-276 
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    ISSN: 1432-0878
    Keywords: Endocrine glands ; Mouse small intestine ; Mouse embryo ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The duodenum and ileum of 15 to 18-day old Swiss ICR mouse embryos were studied with the electron microscope to follow the differentiation of endocrine cells. Endocrine cells were classified on purely morphological characteristics. EC cells appeared at 16 days of gestation in both segments. At the same stage G cells were seen in the duodenum and K cells in the ileum. ECL, and S cells were identified in the duodenum at 17 days. Finally, D cells were seen at 18 days of gestation in the duodenum and ileum. With the electron microscope, endocrine cells were not identified in the small intestine of the mouse before the formation of villi.
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    URL: http://dx.doi.org/10.1007/BF00220744
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    Immunoreactive excitatory amino acids in the parietal eye of lizards, a comparison with the pineal organ and retina (1997)
    Springer
    Cell & tissue research 287 (1997), S. 275-283 
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    ISSN: 1432-0878
    Keywords: Key words: Parietal eye ; Pineal organ ; Retina ; Glutamate ; Aspartate ; Immunocytochemistry ; Electron microscopy ; Lacerta muralis ; Lacerta agilis ; Lacerta viridis (Lacertilia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The fine structure of the organ and the localization of the excitatory amino acids glutamate and aspartate were studied in the parietal eye of lizards by postembedding immunoelectron microscopy. The parietal eye contains cone photoreceptor cells, secondary neurons, and ependymal and lens cells. The photoreceptors form long inner and outer segments, some of them being paired as ”twin-photoreceptors” by zonulae adherentes. Perikarya of neurons bear sensory cilia (containing 9×2+0 pairs of tubules) extending into the intercellular space. No neurohormonal terminals are present in the parietal eye. A higher immunoreactivity to glutamate than to aspartate is found in the photoreceptors and in the secondary neurons of the parietal eye. Glutamate immunogold labeling is more intense in the axonal processes of photoreceptors and neurons and in most of the nerve fibers of the parietal nerve running to the brain stem. Weak aspartate and glutamate immunoreactivity can be detected in the ependymal and lens cells. A similar distribution of immunoreactive amino acids is found in the photoreceptors, secondary neurons, and ependymal glial elements of the pineal organ, and retina of the lateral eye of the same animals. Immunoreactive glutamate accumulates in the axons of photoreceptors and secondary neurons of the parietal eye suggesting that this excitatory amino acid acts as a synaptic mediator in the neural efferentation of the organ. Thus, the efferent light-conducting pathway of the parietal organ is similar to that of the pineal organ and lateral eye retina. As the Mullerian cells of the retina, the ependymal and lens cells of the parietal eye and the ependymal-glial cells of the pineal organ may play a role in the metabolism and/or elimination of excitatory amino acids released by photoreceptors.
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    URL: http://dx.doi.org/10.1007/s004410050752
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    Expression of basic fibroblast growth factor-like immunoreactivity in the nuclei of regenerating hepatocytes (1997)
    Springer
    Cell & tissue research 288 (1997), S. 517-527 
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    ISSN: 1432-0878
    Keywords: Key words: Liver ; Subcellular fractions ; Immunohistochemistry ; Electron microscopy ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. This study, utilizing rats subjected to two-thirds partial hepatectomy or sham operation, was designed (1) to investigate the content of basic fibroblast growth factor (bFGF) in the subcellular fractions of regenerating and sham-operated rat livers by immunoblot experiments and enzyme-linked immunosorbent assay (ELISA), (2) to show that bFGF immunoreactivity and proliferating cell nuclear antigen (PCNA) immunoreactivity are markers for hepatocellular mitosis before and after partial hepatectomy, and (3) to observe the location and fine structure of the bFGF immunoreaction within the regenerating liver with special attention to bFGF immunoreactivity in the nuclei of regenerating hepatocytes. Immunoblot experiments and ELISA showed a transient increase in high-molecular-weight forms of bFGF in the nuclear subcellular fraction of regenerating liver 48 h after partial hepatectomy. By light microscopy, bFGF and PCNA immunoreactivities were detected in the nuclei of regenerating hepatocytes. Electron microscopy demonstrated bFGF-like immunoreactivity mainly in the nuclear euchromatin and rarely in the heterochromatin or nucleoli of regenerating hepatocytes. The transient increase in high-molecular-weight forms of bFGF in the nuclear euchromatin of regenerating hepatocytes, together with the concomitant expression of PCNA in the regenerating liver, suggests an important role of the high-molecular-weight forms of bFGF in hepatocyte proliferation and/or mitosis, although authentic bFGF with a molecular form of 18 kDa is not considered to be involved in hepatic regeneration.
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    URL: http://dx.doi.org/10.1007/s004410050837
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    Variable patterns of actin filaments in mammalian skeletal muscle (1977)
    Springer
    Cell & tissue research 185 (1977), S. 285-288 
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    ISSN: 1432-0878
    Keywords: Striated muscle (mammalian) ; Myofilaments ; Actin filaments ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural organization of myofilaments in skeletal muscle was studied in four mammalian species (mouse, rat, hamster, goat). In all these species, myofibrils showing irregularly distributed arrays of a variable number of actin filaments (from 6 to 11) were observed. The proportion of such myofibrils and the predominant patterns of actin filaments varied from one species to another. These results are in agreement with those previously reported for human skeletal muscle.
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    URL: http://dx.doi.org/10.1007/BF00220672
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    The effects of aging on satellite cells in skeletal muscles of mice and rats (1977)
    Springer
    Cell & tissue research 185 (1977), S. 399-408 
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    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Satellite cells ; Aging ; Regeneration ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Myosatellite cells were examined and quantified at the fine structural level of resolution during aging of skeletal muscles in mice and rats. Satellite cells in the soleus and gastrocnemius muscles of animals between eight and 30 months of age appeared, according to morphological criteria, metabolically less active than those examined in immature muscles. In the soleus muscle of the mouse, satellite cells decreased in number from 4.6% at eight months of age to 2.4% at 30 months. This decrease appeared to be due to the passage of some satellite cells into the interstitial space as a result of the formation of external lamina material around the entire satellite cell surface.
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    URL: http://dx.doi.org/10.1007/BF00220299
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    “Sunbursts” and “christiesomes”: Cellular fragments in normal cow and goat milk (1977)
    Springer
    Cell & tissue research 185 (1977), S. 535-545 
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    ISSN: 1432-0878
    Keywords: Milk (goat, cow) ; Cell fragments ; Origin ; Triglyceride synthesizing capacity ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Goats' milk includes numerous cell fragments (“christiesomes”) which originate from the mammary secretory cells, contain well preserved endoplasmic reticulum, mitochondria and lipid droplets, and are responsible for the considerable triglyceride synthesising capacity of fresh goat milk. Cows' milk shows a few such particles only after repeated oxytocin-aided milkings. Cows' milk does contain quite different particles which have a dense content with a few small vesicles and numerous microvillus-like protrusions on one side (“sunbursts”). These have not been found in goats milk. Cytoplasmic particles similar to sunbursts have been found on the surface of the mammary secretory epithelium. It is suggested that they are residues of dead cells.
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    URL: http://dx.doi.org/10.1007/BF00220657
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    The myelination of the cerebellar cortex in the cat (1978)
    Springer
    Cell & tissue research 188 (1978), S. 509-520 
    Details
    ISSN: 1432-0878
    Keywords: Cerebellar cortex (Cat) ; Postnatal development ; Myelination of efferent and afferent fiber systems ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The myelination of the cerebellar cortex of the cat was investigated in 61 cats aged from 3 hrs post partum to two and a half years. The first myelinated fibers appear at the time of birth in the central medullary ray. Before the onset of myelination, all fibers reach a critical diameter of about 1 μm. About the 14th day of life the number of oligodendrocytes in the prospective white matter increases markedly. Thereafter, the oligodendrocytes invade the inner granular layer. It therefore seems that the myelination of the cerebellar cortex proceeds from the central medullary ray towards the granular layer. At the 60th day of postnatal life, most of the afferent and efferent fiber systems are myelinated. These findings are discussed in relation to the development of function and the maturation of the electrical activity of the cerebellar circuit.
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    URL: http://dx.doi.org/10.1007/BF00219788
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    The interstitial cells in the renal medulla of rat, rabbit, and gerbil in different states of diuresis (1978)
    Springer
    Cell & tissue research 189 (1978), S. 1-18 
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    ISSN: 1432-0878
    Keywords: Kidney medulla ; Rat, rabbit, gerbil ; Interstitial cells ; Lipid droplets ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The inner zone of the renal medulla of rats, gerbils, and rabbits was investigated to determine whether or not there are any characteristic ultrastructural differences between the interstitial cells of these species. The effects on the interstitial cells of water deprivation and water loading were also investigated. In all three species, the Type 1 interstitial cells, the lipid containing cells, were abundant and their distribution and topographical relations as well as their general ultrastructure were similar. The previously reported significantly higher frequency in desert rats could not be confirmed. Although the lipid droplets of the interstitial cells were smaller in gerbils and rabbits when compared to rats, their fine structure was similar. Their electron dense outer zone was sometimes associated with a granular material and/or a lamellar material with a periodicity of about 40 Å resembling phospholipid “myelin figures”. Water-loaded rats showed a considerable increase in the number of lipid droplets when compared to dehydrated or untreated animals. In contrast, the interstitial cells of waterloaded gerbils and rabbits were depleted of lipid droplets.
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    URL: http://dx.doi.org/10.1007/BF00223117
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    Osmoregulatory mutants that affect the function of the contractile vacuole inChlamydomonas reinhardtii (1997)
    Springer
    Protoplasma 200 (1997), S. 99-111 
    Details
    ISSN: 1615-6102
    Keywords: Chlamydomonas reinhardtii ; Contractile vacuole ; Electron microscopy ; Videomicroscopy ; Osmoregulation ; Osmoregulatory mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Four independent osmoregulatory mutants,osml, osm3,osm4, and osm7, were isolated on the basis of their requirement for growth medium of high osmotic strength. In normal low-osmoticstrength medium, in contrast to wild-type cells, the mutants grow poorly or not at all; in distilled water mutant cells are immobilized and eventually swell and burst. The mutants were examined by ordinary brightfield and phase-contrast microscopy, videomicroscopy, and electron microscopy. The four mutants showed different defects in the contractile vacuole (CV) cycle. Timing of various stages of the CV cycle showed thatosm1 was affected primarily in the early stage of the cycle when the CV begins to grow,osm3 primarily in midcycle when vacuoles fuse to form the CV proper,osm7 at a late stage of the cycle at docking and fusion of the CV with the plasma membrane, andosm4 during contraction of the CV. At the electron microscopic level, in dilute medium, mutant cells by comparison with wild-type cells had large autophagosomes, swollen mitochondria, and dilated ER cisternae. Although electron microscopy showed general abnormalities of the contractile vacuoles consistent with the videomicroscopic observations of living cells, no obvious vacuole membrane abnormalities were seen which would explain the mutational defects. The mutations help define the separate processes that contribute to the coordinated CV cycle inChlamydomonas, and open the way to eventual isolation of some of the genes responsible for CV function.
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    Structure and behavior of contractile vacuoles inChlamydomonas reinhardtii (1997)
    Springer
    Protoplasma 198 (1997), S. 73-84 
    Details
    ISSN: 1615-6102
    Keywords: Chlamydomonas reinhardtii ; Contractile vacuole ; Osmoregulation ; Videomicroscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The contractile vacuole (CV) cycle ofChlamydomonas reinhardtii has been investigated by videomicroscopy and electron microscopy. Correlation of the two kinds of observation indicates that the total cycle (15 s under the hypo-osmotic conditions used for videomicroscopy) can be divided into early, middle, and late stages. In the early stage (early diastole, about 3 s long) numerous small vesicles about 70–120 nm in diameter are present. In the middle stage (mid-diastole, about 6 s long), the vesicles appear to fuse with one another to form the contractile vacuole proper. In the late stage (late diastole, also about 6 s long), the CV increases in diameter by the continued fusion of small vesicles with the vacuole, and makes contact with the plasma membrane. The CV then rapidly decreases in size (systole, about 0.2 s). In isosmotic media, CVs do not appear to be functioning; under these conditions, the CV regions contain numerous small vesicles typical of the earliest stage of diastole. Fine structure observations have provided no evidence for a two-component CV system such as has been observed in some other cell types. Electron microscopy of cryofixed and freeze-substituted cells suggests that the irregularity of the profiles of larger vesicles and vacuoles and some other morphological details seen in conventionally fixed cells may be shrinkage artefacts. This study thus defines some of the membrane events in the normal contractile vacuole cycle ofChlamydomonas, and provides a morphological and temporal basis for the study of membrane fusion and fluid transport across membranes in a cell favorable for genetic analysis.
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    URL: http://dx.doi.org/10.1007/BF01282133
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    Selective UV-induced damage to short-wavelength receptor cells in the butterflyPapilio xuthus (1997)
    Springer
    Protoplasma 200 (1997), S. 112-115 
    Details
    ISSN: 1615-6102
    Keywords: Electron microscopy ; UV-induced cell damage ; Photoreceptor ; Eye ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A technique that allows the specific inactivation of short-wavelength-sensitive photoreceptive cells has been needed for a long time. Such a technique could be useful in studies on the role(s) of UV-receptors in circadian rhythmicity, recognition of floral patterns, homing behaviour, and mate selection in arthropods. We provide ultrastructural evidence that short-wavelength receptor cells can be selectively damaged without affecting other spectral-cell types. Since the method does not require the killing of the experimental animal, the latter can be used in behavioural or other follow-up tests.
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    URL: http://dx.doi.org/10.1007/BF01280739
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    Chrysosphaerella (Pseudochrysosphaerella)solitaria, spec. nova (Chrysophyceae) (1978)
    Springer
    Plant systematics and evolution 129 (1978), S. 135-142 
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    ISSN: 1615-6110
    Keywords: Algae ; Chrysophyceae ; Chrysosphaerella solitaria ; Electron microscopy ; phytoplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new unicellular species of the genusChrysosphaerella (Chrysophyceae) was found in fresh-water ponds in Switzerland, Japan, and the U.S.A. It is described asC. solitaria. The genus is divided into two subgenera:Chrysosphaerella, comprising the colonial species, andPseudochrysosphaerella, the unicellular ones.
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    URL: http://dx.doi.org/10.1007/BF00988987
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    Fine structure and metabolic adaptation of red and white muscles in tuna (1978)
    Springer
    Environmental biology of fishes 3 (1978), S. 185-191 
    Details
    ISSN: 1573-5133
    Keywords: Euthynnus affinis ; Electron microscopy ; Kawakawa tuna ; Red fibres ; White fibres ; Muscle size ; Activity ; Thermogenesis ; Thermal inertia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis An electron microscopic study of the red and white muscle fibres in the trunk musculature of the Kawakawa tuna (Euthynnus affinis) was carried out with a view to correlating their structure with metabolic adaptation. The red fibres which are considerably smaller in diameter (34.58 μm ± 6.16 S.D.) are characterized by their high content of myoglobin, mitochondria, lipid droplets and glycogen granules. The white fibres which are relatively larger in diameter (66.03 μm ± 11.59 S.D.) are characterized by their lack of myoglobin, low mitochondria) density, high content of glycogen granules and the conspicuous absence of lipid droplets. The characteristics in fine structure of the two fibre types are discussed in the light of their metabolic adaptation, the red fibres as being adapted for long term cruising movement utilizing lipid as the main source of energy and the white fibres for short bursts of activity metabolizing glycogen as the chief fuel. The tuna, with the acquisition of the counter-current heat exchange system which provides for the retention of the heat generated from high substrate oxidation in the red muscle and an efficient respiratory system, it is postulated, is well adapted for high speed sustained swimming.
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    URL: http://dx.doi.org/10.1007/BF00691942
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    Stereological and biochemical analysis of prolactin and growth hormone secreting rat pituitary cells in culture (1977)
    Springer
    Cell & tissue research 184 (1977), S. 169-178 
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    ISSN: 1432-0878
    Keywords: Pituitary cell cultures (rat) ; Prolactin ; Electron microscopy ; Stereology ; Non-parametric statistics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The secretion of prolactin is increased by treatment of prolactin producing rat pituitary cells with the hypothalamic tripeptide thyroliberin. To investigate the underlying mechanisms we used three closely related rat pituitary tumor cell strains (GH12C1, GH3 and GH4C1), which synthesize and spontaneously secrete prolactin and/or growth hormone. Growth hormone and prolactin released into the culture medium over a period of 24 h were measured by radioimmunoassay. Initial rates of synthesis were measured by immunoprecipitation of intracellular growth hormone and prolactin after incubation of cell cultures with 3H-leucine. The observed increase in prolactin synthesis and release was correlated with morphological effects of thyroliberin treatment. The volume density of Golgi complexes and the volume and surface densities of rough endoplasmic reticulum were compared in untreated cells and thyroliberin treated cells. As normal distribution could not be assumed, the non-parametric rank test of Wilcoxon was used whereby the densities calculated for each cell section were ranked. Alle three morphological parameters increased after thyroliberin treatment in cells secreting prolactin only (GH4C1), implying that the increase of prolactin secretion, at lest in part, is due to increased prolactin synthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223066
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    A possible role for placental lysosomes in the formation of villous syncytiotrophoblast (1977)
    Springer
    Cell & tissue research 178 (1977), S. 411-419 
    Details
    ISSN: 1432-0878
    Keywords: Human placenta ; Lysosomes ; Differentiation of cytotrophoblast ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An ultrastructural and ultrahistochemical study of first trimester human placentae confirms previous reports that the cytotrophoblastic cells show a spectrum of differentiation, that dissolution of the limiting membrane of the cytotrophoblastic cells occurs and that fragments of free membrane can be found in the syncytiotrophoblast. There is an aggregation of primary lysosomes in the region of approximation of the cytotrophoblast to the syncytiotrophoblast, free lysosomal enzymes are found in the space between the two trophoblastic components, secondary lysosomes have been noted in the vicinity of fragmenting cytotrophoblastic cell membrane and the incorporation of a segment of free membrane into a vesicular structure has been noted. It is suggested that placental lysosomes mediate the dissolution of the cytotrophoblastic cell membranes that is a necessary prerequisite for their full differentiation into syncytiotrophoblast and it is further suggested that one of the principal roles of placental lysosomes is in the structural refashioning of the organ that occurs during the first trimester.
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    URL: http://dx.doi.org/10.1007/BF00218704
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  • 85
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    Postnatal development of the suprachiasmatic hypothalamic nucleus of the rat (1977)
    Springer
    Cell & tissue research 178 (1977), S. 463-475 
    Details
    ISSN: 1432-0878
    Keywords: Hypothalamus (Rat) ; Visual pathways ; Synapses ; Electron microscopy ; Circadian rhythms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Light and electron microscopy of newborn, four day, one, two, three and five week old rats revealed principally a progressive increase in the diversity and number of synaptic contacts in the suprachiasmatic nucleus (SCN). The major increase in synaptic diversity occurred between four days and one week of age. Correlation between this finding and the adult synaptic morphology of SCN (Güldner, 1976) on the one hand, and the ontogeny of circadian rhythms on the other were made. This suggested that the retinal afferents arriving on day four form asymmetrical contacts with dendrites. While increase in synaptic number was progressive, it was most marked between three and five weeks of age. By five weeks, most features of the adult SCN were present. No significant morphological effects were evident as a result of neonatal retinal lesions.
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    URL: http://dx.doi.org/10.1007/BF00219568
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  • 86
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    Electron microscopic study on the early histogenesis of thymus in the toad, Xenopus laevis (1977)
    Springer
    Cell & tissue research 179 (1977), S. 87-96 
    Details
    ISSN: 1432-0878
    Keywords: Thymus ; Histogenesis ; Electron microscopy ; Xenopus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sequential electron microscopic observations of thymic histogenesis in the toad, Xenopus laevis, reveal that the thymus arises as epithelial buddings of the visceral pouches at Nieuwkoop-Faber stage 40, and acquires its basic histological features at stages 48–49. In the rudiments and the surrounding mesenchyme at stages 43–45, there are non-epithelial cells with pseudopodia, abundant ribosomes, and marginated heterochromatin. These cells, possible precursor cells of thymic lymphocytes, are frequently observed to attach and pass through the basal lamina which coats the thymic rudiment. The proliferation and differentiation of large lymphocytes are evident at stage 47. During stages 48–49 the small lymphocytes, lymphoid cortex and epithelial medulla including the thymic cysts, differentiate, and vascularization occurs. The results provide an ultrastructural basis for recent experimental evidence that the thymus exerts its essential function at stages 47–48. The possibility of non-epithelial derivation of thymic lymphocytes is discussed.
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    URL: http://dx.doi.org/10.1007/BF00278464
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  • 87
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    Fine structure of rabbit ear chondrocytes in vitro and after autotransplantation (1977)
    Springer
    Cell & tissue research 180 (1977), S. 341-356 
    Details
    ISSN: 1432-0878
    Keywords: Ear chondrocytes (rabbit) ; Cell culture ; Transplantation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Chondrocytes were isolated enzymatically from rabbit ear cartilage, grown in vitro or as autotransplants for 1, 2 or 5 weeks and then examined by transmission electron microscopy. A confluent monolayer formed rapidly in vitro and the cells later grew in multiple overlapping layers, producing thick sheets of cartilaginous tissue. The cells retained a normal structure throughout the period of observation and, like the chondrocytes in intact cartilage, showed numerous microfilaments, an extensive granular endoplasmic reticulum and a prominent Golgi complex. Large amounts of intercellular matrix were laid down in vitro consisting of thin collagen fibrils, small rounded or polygonal granules believed to represent proteoglycans and patches and fibres of elastin. Chondrocytes in intramuscular autotransplants reconstituted an elastic cartilage. The exogenous origin of the cells in the transplants was verified by labeling of the lysosomes by exposure of the cells to colloidal thorium dioxide particles prior to injection. Structurally, the cells and the matrix of the transplants conformed to the above description. Accumulations of elastin-like material were sometimes observed in the Golgi vacuoles of the cells. Extracellularly, such conglomerates aggregated in connection with bundles of microfibrils, building up mature elastic fibres with a dense amorphous structure. The culture and transplant systems characterized here provide suitable experimental models for studies on development, growth and aging of elastic cartilage, including various aspects of the formation and turnover of elastic fibres and other macromolecular matrix components.
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    URL: http://dx.doi.org/10.1007/BF00227600
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  • 88
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    Role of zinc and calcium in the formation and storage of insulin in the pancreatic β-cell (1978)
    Springer
    Cell & tissue research 188 (1978), S. 107-118 
    Details
    ISSN: 1432-0878
    Keywords: Pancreatic β-cells (mouse) ; Formation and storage of insulin ; Role of zinc and calcium ; Culture of islets ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The effects of culture of isolated mouse islets of Langerhans for up to 9 days in media which had been depleted of zinc electrochemically or with the chelating agent Tris-(2-aminoethyl) amine, or of calcium, have been compared. 2. An 83% reduction of extracellular zinc concentration did not adversely affect proinsulin biosynthesis, conversion of proinsulin to insulin, or the ability of cells to store newly formed insulin in granules. When incubation media were depleted of both zinc and calcium the β-cells produced abnormally large electron-lucent granules, consistent with the failure of insulin to crystallise within the granule sac. 3. Very similar results, with formation of large electron lucent granules, were obtained after culture of islets in the absence of calcium but in the presence of normal concentrations of zinc. 4. It is suggested that zinc may play a less critical role in the biosynthesis of proinsulin and its conversion to insulin, while calcium may have a more important function in insulin storage, than has sometimes previously been supposed.
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    URL: http://dx.doi.org/10.1007/BF00220518
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  • 89
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    Electron microscopic immunocytochemical demonstration of separate mesotocinergic and vasotocinergic nerve fibres in the pars intermedia of the amphibian hypophysis (1977)
    Springer
    Cell & tissue research 178 (1977), S. 175-181 
    Details
    ISSN: 1432-0878
    Keywords: Pars intermedia of hypophysis ; Rana temporaria ; Mesotocinergic and vasotocinergic fibres ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary With the use of the unlabeled antibody peroxidase-antiperoxidase (PAP) method at the electron microscopic level, it has been shown that the pars intermedia of the hypophysis of Rana temporaria contains a diffuse intercellular network of separate mesotocinergic and vasotocinergic nerve fibres.
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    URL: http://dx.doi.org/10.1007/BF00219045
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    Electron microscopic studies on the development of the chorion of the viviparous teleost Dermogenys pusillus (Hemirhamphidae) (1977)
    Springer
    Cell & tissue research 179 (1977), S. 255-270 
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    ISSN: 1432-0878
    Keywords: Chorion formation ; Viviparity ; Dermogenys pusillus ; Teleosts ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Eight stages in the oogenesis of Dermogenys pusillus were selected in order to demonstrate the formation of the egg membrane. In young oocytes (stages 1 and 2) the contact between oocyte and follicular cells is rather close. During stage 3 microvilli arise from the oocyte, and the follicular cells protrude lobopodia-like cell processes. When the microvilli have become arranged more regularly, the homogeneous material of the zona radiata externa is deposited between them (stage 4). During the subsequent stage (5) the inhomogeneous zona radiata interna appears. It attains its greatest thickness and its characteristic fine structure during stage 6. It then consists of cross-banded fibrillae and lamellae. Later on (stage 7) the egg membrane flattens, and finally it is a compact chorion consisting perhaps of very fine fibrils. Because of this development and of its complex fine structure the egg membrane of Dermogenys like that of Zoarces resembles that of oviparous teleosts but remains considerably thinner. The eight stages of oogenesis in Dermogenys are compared with those described by Arndt (1956) in several limnetic teleosts.
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    URL: http://dx.doi.org/10.1007/BF00219800
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  • 91
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    Changes in the morphology of ribosomes in uterine epithelial cells under various hormonal conditions (1977)
    Springer
    Cell & tissue research 179 (1977), S. 517-530 
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    ISSN: 1432-0878
    Keywords: Ribosomes ; Uterine epithelium ; Estradiol ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural morphology of “free” cytoplasmic ribosomes of rat uterine epithelial cells was studied during diestrus, estrus, after ovariectomy, and after estradiol-17β administration to rats that were ovariectomized 1 to 25 weeks before hormone treatment. A change in size and contrast of ribosomes was observed concomitant with a transition from pre-existing monosomes to polysomes depending on the dose of estradiol and its route of application. In 3 weeks ovariectomized rats these changes in ribosomal granules take place at approximately the same time (30–45 min) when synthesis of “induced protein” was described biochemically. The morphological events after estradiol administration are discussed with respect to a primary site of estrogen action.
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    URL: http://dx.doi.org/10.1007/BF00219853
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  • 92
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    Electron microscopic study on the innervation of the pancreas of the domestic fowl (1977)
    Springer
    Cell & tissue research 180 (1977), S. 453-465 
    Details
    ISSN: 1432-0878
    Keywords: Pancreas ; Fowl ; Innervation ; Synaptic vesicles ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the pancreas of the domestic fowl was studied electron microscopically. The extrapancreatic nerve is composed mostly of unmyelinated nerve fibers with a smaller component of myelinated nerve fibers. The latter are not found in the parenchyma. The pancreas contains ganglion cells in the interlobular connective tissue. The unmyelinated nerve fibers branch off along blood vessels. Their synaptic terminals contact with the exocrine and endocrine tissues. The synaptic terminals can be divided into four types based on a combination of three kinds of synaptic vesicles. Type I synaptic terminals contain only small clear vesicles about 600 Å in diameter. Type II terminals are characterized by small clear and large dense core vesicles 1,000 Å in diameter. Type III terminals contain small clear vesicles and small dense core vesicles 500 Å in diameter. Type IV terminals are characterized by small and large dense core vesicles. The exocrine tissue receives a richer nervous supply than the endocrine tissue. Type II and IV terminals are distributed in the acinus, and they contact A and D cells of the islets. B cells and pancreatic ducts are supplied mainly by Type II terminals, the blood vessels by Type IV terminals.
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    URL: http://dx.doi.org/10.1007/BF00220168
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  • 93
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    Neuritic growth cone and ependymal gap junctions in the feline subfornical organ during early development (1977)
    Springer
    Cell & tissue research 181 (1977), S. 27-36 
    Details
    ISSN: 1432-0878
    Keywords: Central nervous system (Subfornical organ) ; Gap junctions ; Neuritic growth cones ; Ependyma ; Electron microscopy ; Freezeetching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intercellular contacts in the subfornical organ (SFO) of kittens 3, 16, and 29 days old were studied in thin sections and by the freeze-etch method. Gap junctions appeared between growing nerve processes and target cells. The junctions were interspersed between immature synapses lacking mitochondria as well as full preand postsynaptic membrane specializations. Gap junctions were seen on filopodia as well as on more mature processes. The morphology of these junctions was typical of those described earlier but they were of small size (0.2–0.3 μm). Gap junctions of peculiar form were also seen between ependymal elements in the SFO at 16 days. These were of large size (0.5–0.8 μm) and were often of segmented character. This segmentation consisted of bands 3–4 particles in width with a center-to-center spacing of 90 nm with particle free corridors between corresponding to the width of about two rows of particles. The margin of the group might be circumscribed by a row of particles. Although gap junctions of large size were seen between ependymal cells in thin section, features corresponding to the particle free corridors have not been observed to date.
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    URL: http://dx.doi.org/10.1007/BF00222772
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    Tubules invaginating from the sarcolemma in the subneural region of muscle fibers (1977)
    Springer
    Cell & tissue research 181 (1977), S. 73-79 
    Details
    ISSN: 1432-0878
    Keywords: Muscles ; Neuromuscular junction ; T-system ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sarcoplasmic tubules invaginating from the sarcolemma of the subneural region of muscle fibers are described in Atlantic hagfish and rat. In rat, the tubules invaginate from the bottoms of the secondary synaptic clefts. The density of tubule openings may be higher than the density of T-tubule openings elsewhere along muscle fibers.
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    URL: http://dx.doi.org/10.1007/BF00222775
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  • 95
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    Granular cells in the connective tissue of Helix pomatia L. (Gastropoda, Pulmonata) (1977)
    Springer
    Cell & tissue research 181 (1977), S. 91-103 
    Details
    ISSN: 1432-0878
    Keywords: Granular cells ; Helix pomatia ; Electron microscopy ; Electrophoresis ; Secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Granular cells (cells crowded with colourless granules staining with paraldehyde fuchsin according to Gomori-Gabe and not containing calcium) are independent cells in the connective tissue of Helix pomatia. Histochemical data suggest that the granules are rich in sulfhydryl-containing proteins, but lack biogenic monoamines. Electron microscopic investigations confirm the supposed secretory activity of the granular cells. Secretory proteins are presumed to be synthetized in the endoplasmic reticulum and condensed in the Golgi apparatus giving rise to the granules. Extrusion occurs by exocytosis. Electrophoresis of homogenates, prepared from tissues containing numerous granular cells, results in the separation and identification of a secretory protein from the granular cells. An electrophoretically homologous protein is recognized in the hemolymph, but in very small quantities. Our findings and the work of others suggest the involvement of granular cells in neuroendocrine events.
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    URL: http://dx.doi.org/10.1007/BF00222777
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    Secretion in the rat coagulating gland (Anterior Prostate) after copulation (1977)
    Springer
    Cell & tissue research 181 (1977), S. 519-529 
    Details
    ISSN: 1432-0878
    Keywords: Rat prostate ; Copulation ; Secretion ; Cytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of copulation on the rat coagulating gland (anterior prostate) was studied. At 4 to 6 h after the beginning of copulation the coagulating glands of rats that had produced copulatory plugs were nearly empty of secretion. Ultrastructurally, the coagulating gland has large cisternae of rough endoplasmic reticulum (RER) and few condensing vacuoles or secretion granules. After copulation the number of secretion granules and the frequency of their expulsion into the lumen increased. Also in the lumen were “fragmentation” vesicles (50–100 nm diameter) that were bounded by a unit membrane and appeared to arise from microvilli. At 4, 6, and 7h after the beginning of copulation there was an increase in apical blebbing. Blebbing was found in both perfusion and immersion-fixed tissue. Also, after copulation there was an increase in “light cells” that were characterized by reduced RER cisternae, an electron lucent cytoplasm, and atrophic Golgi apparatus. The luminal ground substance, secretion granules, and some Golgi elements, contained polysaccharides as seen with the periodic acid-thiocarbohydrazide-silver proteinate method.
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    URL: http://dx.doi.org/10.1007/BF00221773
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    DNA-synthesizing cells in human fetal thymus (1977)
    Springer
    Cell & tissue research 178 (1977), S. 333-339 
    Details
    ISSN: 1432-0878
    Keywords: Thymus, Human fetus ; Lymphocytes ; DNA synthesis ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Fragments and suspensions of human fetal thymus were incubated in the presence of 3H-TdR to permit study of the distribution and morphology of DNA-synthesizing cells. Results of light and EM autoradiography showed that 1. although DNA-synthesizing cells were present in the medulla, the vast majority of these cells were localized in the thymic cortex, 2. cells with the typical EM appearance of small lymphocytes and lymphoid blast cells both synthesized DNA, and 3. cells in S-phase were predominantly 8 to 12 μm in size.
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    URL: http://dx.doi.org/10.1007/BF00218698
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  • 98
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    Penetration of spermatozoon into the ovum and transformation of the sperm nucleus into the male pronucleus in the domestic fowl, Gallus gallus (1978)
    Springer
    Cell & tissue research 190 (1978), S. 89-98 
    Details
    ISSN: 1432-0878
    Keywords: Fertilization ; Membrane fusion ; Male pronucleus ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The apex of the sperm head which has undergone the acrosome reaction comes in contact with the plasma membrane of the ovum. After the entire surface of the inner acrosomal membrane has come into close contact with the plasma membrane of the ovum, the two membranes fuse to form a continuous membrane. All parts of the spermatozoon that are devoid of plasma membrane penetrate into the ooplasm. As the head of the spermatozoon moves deeper into the ooplasm, the chromatin begins to disperse, and the head of spermatozoon is transformed into a large spherical nucleus with low electron density. At a later stage of the transformation, many small vesicles appear around the nucleus and subsequently fuse to form two continuous membranes. These membranes represent the male pronuclear envelope. The condensation of the chromatin occurs in places in the nucleus, so that the male pronucleus is formed. During the course of the formation of the male pronucleus, the subacrosomal rod and tail become detached from the head and disintegrate.
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    URL: http://dx.doi.org/10.1007/BF00210039
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  • 99
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    On the ampullary organs of the South-American paddle-fish Sorubim lima (Siluroidea, Pimelodidae) (1978)
    Springer
    Cell & tissue research 190 (1978), S. 357-369 
    Details
    ISSN: 1432-0878
    Keywords: Ampullary organs ; Siluroidea ; Sensory cells ; Synaptic junctions ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ampullary organs were found in the epidermis of the paddle-fish Sorubim lima; they are distributed all over the skin surface of the fish but are particularly densely grouped in the head region and on the dorsal surface of the paddle. Histological and electron microscopical observations show that their structure is similar to the type of cutaneous ampullary organs characteristic of other Siluroidea. Composed of a relatively large mucus-filled ampulla, the organ possesses a short and narrow canal which leads to the outer epidermal surface. The wall of the ampulla is formed of several layers of flat epidermal cells. In general four sensory cells, each one surrounded by supporting cells, compose the sensory epithelium at the bottom of the ampulla. The inner surface of the sensory cells in contact with the ampullary mucus bears only microvilli. The contact between the nerve endings and the sensory cells show the characteristic structure of an afferent neuro-sensory junction. Two ampullae are innervated in some cases by the same afferent nerve fibre.
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    URL: http://dx.doi.org/10.1007/BF00218181
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  • 100
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    The ultrastructure of the male and female prostate of Praomys (Mastomys) natalensis (1978)
    Springer
    Cell & tissue research 190 (1978), S. 539-552 
    Details
    ISSN: 1432-0878
    Keywords: Prostate ; Praomys natalensis ; Castration ; Changes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Male ventral and female prostates of Praomys (Mastomys) natalensis were examined with the electron microscope. The findings support and add to information obtained with the light microscope on tissues from normal, castrated and ovariectomised animals. Our results indicate that although the female prostate may be considered a homologue of the male ventral prostate anatomically and histologically, there are differences in sub-cellular morphology and hormone dependence. Cells of the intact ventral prostate of the male are characterised by prominent dilated Golgi vesicles and electron-dense “mature secretory granules” seen in the apical region of the cell. In the cells of the female prostate these features are absent. These morphological differences reflect the influence of hormones upon the cells, as shown by the reduction of the dilated Golgi vesicles in the castrated male and conversely, their occasional presence in the cells of the oestrous female. Comparison of castrated and ovariectomised animals shows that the male ventral prostate is much more dependent on androgens than the female is on ovarian hormones. There are several modes of secretion in the male ventral and the female prostate. These are by acellular and cellular blebbing, by a variety of secretory vesicles into the acinar lumina, and by a system of “double walled” vesicles not previously described.
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    URL: http://dx.doi.org/10.1007/BF00219563
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