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  • Electron microscopy  (46)
  • Drosophila  (22)
  • Springer  (68)
  • American Institute of Physics (AIP)
  • Blackwell Publishing Ltd
  • 1980-1984  (68)
  • 1980  (68)
Collection
Keywords
Publisher
  • Springer  (68)
  • American Institute of Physics (AIP)
  • Blackwell Publishing Ltd
  • Wiley-Blackwell  (2)
Years
  • 1980-1984  (68)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Adaptation ofDrosophila enzymes to temperature. III. Evolutionary conservatism in mitochondrial enzymes (1980)
    Springer
    Journal of molecular evolution 16 (1980), S. 37-46 
    Details
    ISSN: 1432-1432
    Keywords: Evolution ; Drosophila ; Temperature ; Mitochondrial enzymes ; Kinetic properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The evolutionary behavior of two mitochondrial enzymes (L-glycerol 3-phosphate:cytochrome c oxidoreductase E.C.1.1.1.95,αGPO, and L-malate: NAD+ oxidoreductase, E.C.1.1.1.37, m-MDH) obtained from several temperate and tropicalDrosophila species was examined by comparing their catalytic properties, which related to temperature (Km-Ea-Q10-Thermostability). MitochondrialαGPO or m-MDH obtained either from temperate or from tropical species was found to exhibit similar catalytic properties while for both cytosolic enzymes, theαGPDH and s-MDH, Km patterns were similar among species from the same thermal habitat and different between thermal habitats. In combination with other observations reported in the literature these facts support the view that the function, and probably the structure, of mitochondrial enzymes are better conserved in evolution than those of the corresponding enzymes found in the cytosol. It is proposed that the relative invariance of the mitochondrial enzymes structure is probably linked to a necessary relative invariance of molecular interactions inside the mitochondrion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01732068
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  • 2
    Electronic Resource
    Electronic Resource
    The effect of temperature onshibire ts cell clones in the compound eye ofDrosophila melanogaster (1980)
    Springer
    Development genes and evolution 188 (1980), S. 55-63 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Compound eye ; shibire ts ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have analysed the effect of temperature on both developing and adult eye cell clones homozygous forshi ST139, a temperature-sensitive mutant ofDrosophila melanogaster. The mutant gene, autonomous in its cellular expression, causes structural modifications of ommatidial cells when adult clones of cells are exposed to the restrictive temperature (29°C) for several days. However, the mutant phenotype reverses to normal within 4 days at the permissive temperature (20°C). The results of pulse, shift-up and shift-down experiments show that the temperaturesensitive period for developing compound eye cells is from the late second instar up to the early pupa. Cytodifferentiation of compound eye cells is blocked by restrictive temperature treatment during this period, whereas cell proliferation does not seem to be directly affected. These results are discussed with regard to the other known aspects of the phenotype observed in mutant individuals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848610
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  • 3
    Electronic Resource
    Electronic Resource
    Morphogenesis in the embryo ofDrosophila melanogaster — Germ band extension (1980)
    Springer
    Development genes and evolution 188 (1980), S. 163-177 
    Details
    ISSN: 1432-041X
    Keywords: Yolk sac ; Ultrastructure ; Embryogenesis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Changes at the ultrastructural level during germ band extension in the embryo ofDrosophila melanogaster are described. Cytoplasmic connections between cells and the yolk sac are present during initial cellular movements. At this time, a continuous system of microfilaments is present adjacent to the membranes in the connections and at the periphery of the yolk sac. As germ band extension progresses, this system becomes discontinuous, and microfilaments are apparent only in the immediate vicinity of the connections. Cytoplasmic connections are disassembled at approximately the midpoint of extension; at the same time, extensive membrane associations develop between germ band cells and between these cells and adjacent yolk sac membranes. Positioning and orientation of cytoplasmic connections suggest that the yolk sac, via these connections, is actively involved in the cellular movements of early germ band extension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00849045
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  • 4
    Electronic Resource
    Electronic Resource
    Developmental studies on two ecdysone deficient mutants ofDrosophila melanogaster (1980)
    Springer
    Development genes and evolution 189 (1980), S. 57-67 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Ecdysone deficient mutants ; Ecdysteroid titer ; Ring gland ; Fine structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This paper describes two ecdysone-deficient, recessive-lethal mutants,lethal(1)giant ring gland (grg) andlethal(1)suppressor of forked mad-ts (mad-ts: Jürgens and Gateff 1979) and compares their ecdysteroid titers with that of the wild-type. Mutant larvae show a much reduced ecdysteroid content, amounting to 1/10 to 1/30 of the wild-type values, but never a true titer peak. They fail to pupate and die after 1–3 weeks. Ecdysteroid feeding elicits different responses in the larvae of the two mutants.mad-ts larvae pupate within 24 h, thus showing that their low ecdysteroid titer is directly connected to their inability to pupate.mad-ts resembles the mutantlethal (3)ecdysone-1 ts (Garen et al. 1977). Thegrg mutant larvae, on the other hand, fail to pupate after 20-hydroxyecdysone feeding as well as injection. The primary defect of thegrg mutant is not entirely clear. Thegrg larval salivary gland cells appear to possess normal ecdysteroid receptors. Furthermore, the low ecdysteroid titer ingrg is not the result of an increased ecdysteroid catabolism. The primary defect in the mutant may lie in the malfunctioning neurosecretory cells which do not show neurosecretion in histological preparations. Further support for this notion comes from electronmicrographs of the enlargedgrg ring glands which, in contrast to the wild-type, do not possess nerve endings. In the wild-type three ecdysteroid peaks were found: one shortly before puparium formation, the second at approximately 12 h and the third at about 30 h after pupation. The ecdysteroid titer peak in late third instar, wild-type larvae is mainly due to the presence of 20-dydroxyecdysone as shown by radioimmunoassays after thin layer chromatography and derivatization followed by gas liquid chromatography and mass spectroscopy. In addition, a number of unidentified polar and apolar metabolites were also present.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848567
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  • 5
    Electronic Resource
    Electronic Resource
    Compartments and distal outgrowth in theDrosophila imaginal wing disc (1980)
    Springer
    Development genes and evolution 188 (1980), S. 157-161 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; Compartments ; Distal outgrowth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Peripheral tissue of the imaginal wing disc gives rise to the proximal mesothoracic structures of the adult. Pieces of peripheral tissue, which have no regenerative capacity when cultured as intact fragments, are capable of distal outgrowth (regeneration) after dissociation and reaggregation. This ability depends on the region of the disc periphery from which the fragment is taken. Extensive distal outgrowth occurs in reaggreages of a fragment containing equal proportions of tissue from anterior and posterior developmental compartments. The extent of outgrowth decreases as the proportion of posterior tissue is reduced, so that a fragment containing only anterior tissue shows no regeneration after dissociation. Limited distal outgrowth occurs in reaggregates of a wholly posterior fragment, but the regenerative capacity is increased greatly when a small amount of anterior tissue is included. It is concluded that distal outgrowth in the wing disc requires an interaction between cells of the anterior and posterior compartments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848808
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  • 6
    Electronic Resource
    Electronic Resource
    Is regeneration inDrosophila the result of epimorphic regulation? (1980)
    Springer
    Development genes and evolution 189 (1980), S. 91-96 
    Details
    ISSN: 1432-041X
    Keywords: Epimorphic regulation ; Drosophila ; Imaginal discs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary It has been known for many years that when a wing disc ofDrosophila is bisected, and the fragments cultured in adult females, regulation occurs and either a complete disc is regenerated or the fragment is duplicated. We have investigated how this regeneration process occurs. To establish which cells contribute to the regenerate, and thus determine if regeneration is the result of epimorphic regulation, fragments of discs, after culture in an adult for one to five days, were exposed to3H-thymidine to label replicating cells. Imaginal discs, both whole and as regenerating fragments, undergo some DNA replication which is distributed throughout the disc, but cut discs frequently show clusters of labelled cells around the wound, indicating that regeneration is probably epimorphic.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848497
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  • 7
    Electronic Resource
    Electronic Resource
    Embryogenesis inDrosophila: Can a single mechanism explain the developmental segregation of germ-line and somatic cells and their subsequent determination? (1980)
    Springer
    Development genes and evolution 188 (1980), S. 179-185 
    Details
    ISSN: 1432-041X
    Keywords: Determination ; Germ-line ; Somatic cells ; Inhibitor gradient hypothesis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A hypothesis is presented which explains the segregation of germ cells from somatic cells, and the subsequent determination of both cell types with a single mechanism. This hypothesis is in part based on that of Meinhardt (1977) and can be summarized as follows: In the newly fertilized egg, the action of a sink in the pole plasm leads to the formation of an anterior-posterior gradient of an inhibitor. The concentration of this inhibitor in the posterior 20% of the egg is below that needed to repress synthesis of an activator. When, during the nuclear division stage, nuclei enter this posterior region, synthesis of the activator begins. As the activator is autocatalytic, this leads to the formation of a peak of activator in this region; and since the activator also catalyses the synthesis of the inhibitor, a peak of inhibitor is formed in the same place. The inhibitor then diffuses anteriorly through the periplasm, forming a posterior-anterior gradient. The presence of this inhibitor in the periplasm causes the nuclei that enter the periplasm to form blastoderm cells and to take up particular segmental states appropriate to their position, while those that remain in the yolk-containing plasm develop into vitellophages. The action of the sink in the pole plasm is postulated to result in the formation of the pole cells, and subsequently to direct some of these into forming cells of the germ-line.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00849046
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  • 8
    Electronic Resource
    Electronic Resource
    The morphological response of Kc-H cells to ecdysteroids: Hormonal specificity (1980)
    Springer
    Development genes and evolution 189 (1980), S. 1-15 
    Details
    ISSN: 1432-041X
    Keywords: Cell line ; Drosophila ; Ecdysone ; Ecdysterone ; Hormones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cells of the line Kc, derived fromDrosophila melanogaster embryos, extend long processes when exposed to ecdysteroid hormones. We have devised a quantitative assay for this morphological response, using the subline Kc-H. The assay was used to characterize the conditions required for the response. A halfmaximal response is elicited by approximately 10−8M 20-hydroxyecdysone; the response is saturated by 10−7M 20-hydroxyecdysone, which causes detectable elongation within a few hours, and a maximal response after 2–3 days. The response occurs substantially normally in the absence of serum, during growth in suspension, and in over-crowded cultures. It is not elicited by cyclic nucleotides, vertebrate growth factors, or a variety of other non-ecdysteroid reagents. Of 60 ecdysteroid compounds tested, only those which were active in other insect test systems elicited the response, and the concentrations required were approximately proportional to the concentrations active in other in vitro systems. We conclude that the response of Kc cells to 20-hydroxyecdysone retains basic features of the ecdysteroid response of intact tissues and therefore that Kc cells are a useful model system for studying ecdysteroid action.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848562
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  • 9
    Electronic Resource
    Electronic Resource
    Crosslinking of theDrosophila chorion involves a peroxidase (1980)
    Springer
    Development genes and evolution 189 (1980), S. 187-196 
    Details
    ISSN: 1432-041X
    Keywords: Eggshell ; Chorion ; Peroxidase ; Crosslinking ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary TheDrosophila chorion contains an endogenous peroxidase activity which remains inactive until late stage 14 when it catalyzes the crosslinking of the chorionic proteins. Using explanted follicles developing in vitro, premature, but otherwise normal crosslinking can be induced with hydrogen peroxide and normal crosslinking can be prevented with peroxidase inhibitors. Inhibition or premature activation of the shell peroxidase allows characterization of chorionic filament specific proteins and establishes new criteria for the identification of eggshell components.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00868677
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  • 10
    Electronic Resource
    Electronic Resource
    Expression of the zygotic genome in blastoderm stage embryos ofDrosophila: Analysis of a specific protein (1980)
    Springer
    Development genes and evolution 188 (1980), S. 153-156 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Embryogenesis ; mat (3) 1 mutation ; Two-dimensional gels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The synthesis of a protein which has been detected in blastoderm cells but not in pole cells (Gutzeit and Gehring 1979) has been studied further by means of two-dimensional gel electrophoresis. This protein could not be detected at the nuclear multiplication stage. The protein is translated from mRNA which is transcribed at the blastoderm stage since it is not synthesized in detectable amounts when embryos are injected with α-amanitin prior to the blastoderm stage. Also the protein could not be detected when RNA from freshly laid eggs was translated in vitro. Embryos from females which are homozygous for the mutationmat (3) 1 form pole cells but no blastoderm cells (Rice and Garen 1975). Thesemat (3) 1 embryos, as we will call them in this report, express the protein if aged for a period of time sufficient for completion of blastoderm cell formation in control wild-type embryos.mat (3) 1 embryos and embryos injected with α-amanitin show the same syndrome of visible developmental anomalies; however, the studied protein could only be detected inmat (3) 1 embryos but not in α-amanitin injected embryos.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848807
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  • 11
    Electronic Resource
    Electronic Resource
    Characterization by isoelectric focusing of chorion protein variants inDrosophila melanogaster and their use in developmental and linkage analysis (1980)
    Springer
    Development genes and evolution 189 (1980), S. 17-24 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Geographic strains ; Chorion proteins ; Electrophoretic variants ; Chorion gene linkage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Drosophila melanogaster chorion proteins are characterized on one-dimensional isoelectric focusing (IF) gels. The six major chorion components previously identified on SDS gels are shown to resolve into at least 11 components in our IF system. IF screening of 102 geographic strains ofDrosophila melanogaster revealed seven cases of variation in major chorion components. Two strains, Crimea and Falsterbo, which were monomorphic for a variant B1 protein and two strains, Skafto and Lausanne, which were monomorphic for a variant C1 protein, were chosen for further study. After IF developmental analysis of F1 hybrids had indicated that the sources of the variation resided in the structural genes for these proteins, each variant was crossed to a multiply marked and inverted strain (BLT) to determine the linkage group of the variant gene. To localize genes to more specific sites multiply marked 3rd (SKERO) or X-chromosomal (CB1) (X-PLE) mapping strains were used. In both Crimea and Falsterbo the gene for the B1 protein is located near map location 26 on the 3rd chromosome. In both Lausanne and Skafto the C1 gene is located on the X chromosome. Hence, for the first time, we have demonstrated genetically the non-linkage of two chorion genes, B1 and C1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848563
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  • 12
    Electronic Resource
    Electronic Resource
    Timing and heritability of theNasobemia transformation inDrosophila (1980)
    Springer
    Development genes and evolution 189 (1980), S. 147-153 
    Details
    ISSN: 1432-041X
    Keywords: Homeotic mutant ; Drosophila ; Clonal analysis ; Timing of gene action ; Determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nasobemia (Ns) is a dominant homeotic mutant ofDrosophila melanogaster which converts parts or all of the antenna to mesothoracic leg.Ns has a temperature sensitive period between 48 and 60 h. The hypothesis thatNs acts during this period and is not required thereafter to maintain the homeotic transformation to leg was tested by removingNs fromNs/+ cells at different stages of development through X-ray induced somatic recombination. The expression of theNs homeotic transformation in recombinant wild type (+/+) cells increased sharply between 48 and 65 h. In clones induced after 65 h the expression of the leg transformation was equal in large and small +/+ clones. We interpret these results as supporting the hypothesis that transient action ofNs between 48 and 65 h switches antennal cells to a clonally stable leg determined state whose maintenance does not require futherNs action.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848503
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  • 13
    Electronic Resource
    Electronic Resource
    A scanning electron microscopic investigation of in vitro osteogenesis (1980)
    Springer
    Calcified tissue international 30 (1980), S. 43-50 
    Details
    ISSN: 1432-0827
    Keywords: Osteogenesis ; In vitro ; Electron microscopy ; Mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Chick limb mesenchymal cells differentiate into muscle, cartilage, fibrous, and bone tissue. Previous reports show that when stage 24 limb mesenchymal cells are cultured in vitro, chondrocytes, myocytes, fibrocytes, and osteoblasts can be identified on the basis of morphological and biochemical parameters. The study reported here demonstrates that phenotypic expression in culture seems to be dependent on the initial plating density, Scanning electron microscopic observations indicate that when stage 24 limb mesenchymal cells are initially seeded at high densities (5 × 106 cells per 35 mm culture dish), mounds of cells appear in culture. These mounds represent cartilage nodules composed of a fine fibrous matrix and chondrocytes, surrounded by a loose fibrous connective tissue matrix. Cultures initially plated at intermediate densities (2.0–2.5 × 106 cells/35 mm culture dish) produce a flattened layer of fibrocytes overlying a matrix of collagen fibers and calcium phosphate deposits as determined by electron-microprobe analysis; these observations are indicative of osteoblast expression. Cells seeded at this intermediate density appear larger and possess greater surface area than cells seeded at high density. It is suggested that conditions that permit such increased cell surface area coupled with a relative compaction due to cell crowding may provide conditions permissive for osteogenesis. Based on morphological criteria, it appears that chick limb mesenchymal cell osteogenesis in vitro is not associated with chondrogenesis but represents a separate route of phenotypic expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408605
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  • 14
    Electronic Resource
    Electronic Resource
    Fine structure of fetal rat calvarium; provisional identification of preosteoclasts (1980)
    Springer
    Calcified tissue international 31 (1980), S. 21-28 
    Details
    ISSN: 1432-0827
    Keywords: Rat ; Calvarium ; Electron microscopy ; Preosteoclasts ; Osteoclasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary This is a study of the fine structure of cells of the 20-day fetal rat calvarium. Special attention is given to identifying and characterizing preosteoclasts. These cells are relatively common and located largely, but not exclusively, at the endocranial bone surface. The preosteoclasts are characterized by abundant mitochondria, an incomplete perinuclear Golgi apparatus, and variable-shaped dense granules. The dense granules are unique in appearance in that they contain an internal dense matrix surrounded by a clear halo. Most granules are circular in shape but some are elongate or tubular in form. Granules with identical appearance are observed in osteoclasts. The preosteoclasts are mononucleate, or occasionally binucleate. It is suggested that because preosteoclasts are morphologically distinctive and relatively abundant, it should be feasible to separate these cells from a heterogeneous cell isolate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02407163
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  • 15
    Electronic Resource
    Electronic Resource
    Effects of demineralization in an ethanolic solution of triethylammonium EDTA on solubility of bone matrix components and on ultrastructural preservation (1980)
    Springer
    Calcified tissue international 32 (1980), S. 175-179 
    Details
    ISSN: 1432-0827
    Keywords: Decalcification ; Electron microscopy ; Bone matrix ; Bone glycoproteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A solution of triethylammonium EDTA in 80% ethanol was evaluated as a demineralizing reagent for bone in comparison with aqueous solutions of EDTA. Biochemical analysis and acrylamide gel electrophoresis of extracts of finely powdered bovine bone showed that most of the macromolecular components of the organic matrix extractable in aqueous EDTA were retained when the triethylammonium EDTA reagent was used. Ultrastructural examination of chick tibias decalcified with the reagents showed a better preservation of cellular morphology, especially the membranous components, and more uniformly distributed ground substance, though slightly less in quantity, when the aqueous reagent was used. Use of the two reagents appears to be complementary, the alkylammonium reagent being more appropriate for use in studies of the organic matrix of bone, including immunohistochemical studies of bone glycoproteins. The aqueous reagent is more appropriate for use in studies of cellular ultrastructure.
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    URL: http://dx.doi.org/10.1007/BF02408537
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  • 16
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    The ultrastructure of cell wall formation and of gamma particles during encystment of Allomyces macrogynus zoospores (1980)
    Springer
    Archives of microbiology 128 (1980), S. 179-189 
    Details
    ISSN: 1432-072X
    Keywords: Allomyces ; Zoospores ; Cell wall ; Chitin ; Gamma particle ; Encystment ; Electron microscopy ; Calcofluor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Structural changes during cell wall formation by populations of semisynchronously germinating zoospores were studied in the water mold Allomyces macrogynus. Fluorescence microscopy using Calcofluor white ST (which binds to β-1,4-linked glycans) demonstrated that Calcofluor-specific material was deposited around most cells between 2–10 min after the induction of encystment (beginning when a wall-less zoospore retracts its flagellum and rounds up). During the first 15 min of encystment there was a progressive increase in fluorescence intensity. Ultrastructural analysis of encysting cells showed that within 2–10 min after the induction of encystment small vesicles 35–70 nm diameter were present near the spore surface, and some were in the process of fusing with the plasma membrane. The fusion of vesicles with the zoospore membrane was concomitant with the appearance of electron-opaque fibrillar material outside the plasma membrane. Vesicles similar to those near the spore surface were found within the gamma (γ) particles of encysting cells. These particles had a crystalline inclusion within the electron-opaque matrix. During the period of initial cyst cell wall formation numerous vesicles appeared to arise at the crystal-matrix interface. Approximately 15–20 min was required for the cell wall to be formed. We suggest that the initial response of the zoospore to induction of encystment is the formation of a cell wall mediated by the fusion of cytoplasmic vesicles with the plasma membrane.
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    URL: http://dx.doi.org/10.1007/BF00406156
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  • 17
    Electronic Resource
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    Evidence for supercoiling in the DNA of bacteriophage heads (1980)
    Springer
    Archives of microbiology 126 (1980), S. 277-283 
    Details
    ISSN: 1432-072X
    Keywords: Bacteriophage ; Myxococcus ; λ ; Superooiled DNA ; Cross-linking ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract DNA was partially released from the heads of myxococcus phages and also coliphage λ and examined by electron microscopy by a modification of the Kleinschmidt technique, in which water was used as hypophase. DNA emerged from the heads in patterns suggestive of newly relaxed supercoils. The unreleased DNA appeared to occupy discrete regions in the head. Some closed circles were released from λ heads. When NaCl solution was used as hypophase, the DNA was observed either released from the tail or from the head, in the latter case, supercoiled regions were observed. When NH4OAc solution was used as hypophase, tightly wound structures were released from λ heads; these fields also contained supercoiled circles. The presence of constrained supercoiled domains in newly released phage DNA was confirmed by observing the effects of ethidium bromide on its conformation. Treatment of phage with nitrogen mustard, a bifunctional alkylating agent, preserved supercoiled domains, even when the phage were lysed over water as hypophase. Further experiments suggested that phage inactivation by nitrogen mustard is largely due to restraint of the supercoiled, native, tertiary structure and that DNA-protein cross-linking may be involved in this reaction. The implications of these findings for the conformation of phage DNA in vivo are discussed and a new model for the winding of DNA in phage heads is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00409932
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  • 18
    Electronic Resource
    Electronic Resource
    Immunoferritin labeling of respiratory nitrate reductase in membrane vesicles of Bacillus licheniformis and Klebsiella aerogenes (1980)
    Springer
    Archives of microbiology 127 (1980), S. 39-46 
    Details
    ISSN: 1432-072X
    Keywords: Immunoferritin labeling ; Electron microscopy ; Membrane vesicles ; Nitrate reductase ; Bacillus licheniformis ; Klebsiella aerogenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The indirect immunoferritin labeling method was used to localize the membrane-bound respiratory nitrate reductase in membrane vesicles and protoplasts or spheroplasts of Bacillus licheniformis and Klebsiella aerogenes, respectively. For a comparison of the labeling of the various vesicle preparations, which differed not only in size but also in the percentage of inside-out orientation, a quantification of the results was needed to circumvent the problem of non-specifically bound ferritin. From the results the sidedness of the nitrate reductase in the cytoplasmic membrane of the abovementioned bacteria was determined as being cytoplasmic in B. licheniformis and as transmembranous in K. aerogenes.
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    URL: http://dx.doi.org/10.1007/BF00414353
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  • 19
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    Chemical composition and ultrastructure of cellular and extracellular Moraxella glucidolytica lipopolysaccharides (1980)
    Springer
    Archives of microbiology 128 (1980), S. 12-18 
    Details
    ISSN: 1432-072X
    Keywords: Moraxella glucidolytica ; Electron microscopy ; Lipopolysaccharide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cellular (LPS I) and extracellular (LPS II) lipopolysaccharide were isolated from Moraxella glucidolytica cells grown on ethanol and from the culture fluid, respectively. Both LPS were toxic when injected to mice and chick embryos. These LPS contained glucose, galactose, glucosamine, galactosamine, 2-keto-3-deoxyoctonate and lipids. By permethylation studies, glucose was found to be linked (1→6) and (1→3) in LPS I and only (1→6) in LPS II. Galactose was the terminal non-reducing sugar. Branching occurred at positions 3 and 4 of galactose residues. LPS I was rich in α- and β-hydroxylauric and α-hydroxymyristic acids and LPS II contained mainly stearic and α-hydroxymyristic acids. LPS I was detoxified by mild acid and alkaline treatments. It was also dissociated by sodium deoxycholate and chromatographed on Sephadex G-75. The main fraction was reassociated by removing the surfactant by dialysis. The morphology of LPS I and LPS II was examined by electron microscopy. LPS I (original and reassociated fractions) consisted exclusively of ribbons while LPS II contained ribbons and vesicles.
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    URL: http://dx.doi.org/10.1007/BF00422299
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  • 20
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    Ultrastructure of Ascodichaena rugosa on beech bark (1980)
    Springer
    Archives of microbiology 126 (1980), S. 87-95 
    Details
    ISSN: 1432-072X
    Keywords: Ascodichaena ; Beech bark ; Electron microscopy ; Host-fungus relationship
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ascodichaena rugosa Butin is a corkinhabiting fungus, found frequently on the bark of Fagus sylvatica L. The hyphae of the fungus are distributed solely in the phellem cells, stopping their growth in the last-formed cork cell layer. The cell to cell invasion is effected by penetration hyphae, causing no extensive dissolution of the cork wall. Electron microscopical observations revealed fine structural details of the fruit bodies and of the intracellular hyphae. Of special interest were the finger-like hyaline hyphae in the last-formed layer of cork cells, which are interpreted as haustoria on the basis of the fine structure both of hyphae and host cells. This situation is considered as reflecting a parasitic relationship of Ascodichaena to beech bark. The activity of the fungus led also to the increased production of cork cells, perhaps related to the nutrient supply of the fungus.
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    Functional significance of amylase polymorphism in Drosophila melanogaster. III. Ontogeny of amylase and some α-glucosidases (1980)
    Springer
    Biochemical genetics 18 (1980), S. 51-63 
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    ISSN: 1573-4927
    Keywords: Drosophila ; ontogeny ; amylase ; α-glucosidases ; functional significance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Changes in amylase (E.C. 3.2.1.1), maltase (E.C. 3.2.1.20), sucrase, and PNPGase activities in relation to changes in wet weight and protein content were studied during the development of larvae and adult flies from two strains of Drosophila melanogaster, homozygous for different amylase alleles. All α-glucosidase activities increase exponentially during a large part of larval development, parallel to the increase in weight, and drop at the end of the third instar. Amylase activity of the Amy 1 strain follows the same pattern. In contrast, amylase activity of the Amy 4,6 strain continues its exponential increase longer. In the third larval instar amylase activity in the Amy 4,6 strain becomes much higher than in the Amy 1 strain. During the first hours of adult life amylase activity of the two strains does not differ. Then Amy 4,6 activity starts to rise and becomes much higher (4–5 times) than Amy 1 amylase activity, which remains approximately constant. All adult enzyme activities are much higher than in larvae. Comparison of enzyme activity of amylase and α-glucosidases in larvae and adults confirms that differences in amylase activities can become important only when starch is a limiting factor in the food.
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    Variation in Drosophila acetylcholinesterase (1980)
    Springer
    Biochemical genetics 18 (1980), S. 439-454 
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    ISSN: 1573-4927
    Keywords: Drosophila ; acetylcholinesterase ; insecticide resistance ; electrophoretic variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We examined the Canton-S strain of Drosophila melanogaster for electrophoretic variation of the enzyme acetylcholinesterase. The pattern of bands obtained (stained with acetylthiocholine) depended on age, sex, and tissue (i.e., head vs. body part and hemolymph). However, through mixing experiments, it was concluded that most of these apparent differences were due to modification of the enzyme by unknown substances located in the fly's body. The electrophoretic pattern of head acetylcholinesterase was altered so that it became characteristic of the body which was present during extraction. For example, when heads of D. melanogaster were homogenized in an extract from D. lebanonensis bodies, the characteristic AChse bands of melanogaster were absent and instead the bands of lebanonensis were found. it was found that extraction of adult heads in 0.1 M potassium phosphate buffer alone or with a 2-min exposure to 1 mg/ml trypsin at 20 C gave the most reproducible results, independent of age and sex. Using these conditions, 25 strains of D. melanogaster and 30 strains of D. pseudoobscura were examined without finding any reproducible electrophoretic variant of acetylcholinesterase. In addition, 53 strains from 39 other Drosophila species produced a total of only six electrophoretic forms of the head enzyme. Additional electromorphs were found when whole flies were used, but these were not studied in detail because of the possibility that they could be due to postextraction modification.
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    Biochemical and genetic basis of the response to 5-fluorouracil in Drosophila melanogaster (1980)
    Springer
    Biochemical genetics 18 (1980), S. 717-726 
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    ISSN: 1573-4927
    Keywords: Drosophila ; 5-fluorouracil ; drug response ; thymidylate synthetase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Mutant strains sensitive and resistant to the drug 5-fluorouracil (FU) have been isolated from the wild-type Pac strain of Drosophila melanogaster. The resistant strain, termed flur, is resistant to at least 0.0035%FU (2.7 × 10−4 m) in the food media and exhibits cross-resistance to 5-fluorodeoxyuridine (FUdR) but not to 5-fluorouridine (FUR). The sensitive strain termed flu S , exhibits over 90% mortality on 0.0008% FU (6 × 10−5 m). Genetic analysis indicates that the flu gene is located on the third chromosome, which agrees with results of previous workers. An analysis of the enzyme thymidylate synthetase from the selected sensitive and resistant strains indicates that the resistant strain enzyme possesses an elevated specific activity. Levels 4 times that of the sensitive strain were observed when the enzymes were assayed at 20 C. This increase is apparently not due to induction by FU in the food media. It is suggested that the enzyme thymidylate synthetase may be involved in the resistance process.
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    Developmental regulation of phenylalanine hydroxylase activity in Drosophila melanogaster (1980)
    Springer
    Biochemical genetics 18 (1980), S. 781-791 
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    ISSN: 1573-4927
    Keywords: Drosophila ; phenylalanine hydroxylase ; developmental regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Herein we demonstrate that Drosophila larvae possess a synthetic activity capable of converting phenylalanine to tyrosine. This system is readily extractable and displays many characteristics of phenylalanine hydroxylase systems described in other organisms, the most notable being that a tetrahydropteridine is required for full expression of activity. The level of phenylalanine hydroxylase activity present in the organism varies with the stage of development: from an undetected level of activity at the first larval instar, there is a rapid increase in phenylalanine hydroxylase activity which reaches a peak at the time of puparium formation, after which there is a rapid decrease again to an undetected level.
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    Genetics of male-specific glucose oxidase and the identification of other unusual hexose enzymes in Drosophila melanogaster (1980)
    Springer
    Biochemical genetics 18 (1980), S. 929-937 
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    ISSN: 1573-4927
    Keywords: glucose oxidase ; glucose metabolism ; Drosophila ; sex specific
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A glucose oxidase (GO) has been identified in the ejaculatory duct of male Drosophila melanogaster. Evidence is given that this enzyme was previously misidentified as HEX-1. Genetic analysis indicates that the Go structural gene is located on the third chromosome at 48 ± 0.5 cm. Go is polymorphic in males in populations of D. melanogaster and D. simulans located in Athens, Georgia. Two other hexose enzymes have also been tentatively identified for the first time in Drosophila. These are NAD(P)-glucose dehydrogenase (GODH) and NAD-gluconate dehydrogenase (GNDH). GODH and GNDH are found in both males and females and may circumvent the initial steps in the pentose shunt.
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    Sexual isolation among widely distributed populations ofDrosophila immigrans (1980)
    Springer
    Behavior genetics 10 (1980), S. 401-407 
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    ISSN: 1573-3297
    Keywords: sexual isolation ; Drosophila ; geographic distance ; isolation index ; resource utilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Six strains of the cosmopolitan speciesD. immigrans from the Australian life zone plus one from the USA, show weak sexual isolation and more rarely sexual selection. Levels of sexual isolation cannot be related to geographic distances. Assortative mating may have evolved as a byproduct of ecological divergence.
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    Adaptive strategies in natural populations of Drosophila (1980)
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    Theoretical and applied genetics 57 (1980), S. 257-266 
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    ISSN: 1432-2242
    Keywords: Drosophila ; Ethanol ; Climatic races ; Desiccation ; Development times
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Adult tolerance of ethanol vapour in a closed system containing 12% ethanol in solution, decreases in a cline from southern to northern Australia. However a Darwin population is more tolerant than predicted from its latitude. Ethanol tolerance races in Australia have almost certainly evolved within the last 100–150 years, because of resource unavailability prior to that time. Within populations, variation among isofemale strains is lowest in the climatically extreme southern Melbourne (37°S) and northern Darwin and Melville I. (11–12°S) populations. This suggests low resource diversity within extreme populations compared with the climatically less extreme Brisbane (28°S) and especially Townsville (19°S) populations. For desiccation resistance, the population rankings are: Darwin Melbourne 〉 Townsville 〉 Brisbane Melville I. and for development time, rankings are similar: Darwin Melbourne 〈 Townsville 〈 Brisbane Melville I. Therefore resource utilization heterogeneity is greatest in populations not greatly stressed by desiccation and where development times are extended. In total therefore, the utilization of a diversity of resources is a feature of populations tending somewhat towards a K-strategy; this is emphasized by the relative heterogeneity among isofemale strains of these populations for desiccation resistance and to a lesser extent development times. The D. melanogaster gene pool can be viewed as made up of climate-associated races. Since the ethanol tolerances of adjacent (and climatically similar) Darwin and Melville I. are very different, resource utilization races may occur within climatic races. Such a mosaic of resource utilization races are more likely in climatically extreme than in optimal habitats.
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    Phagocytosis of spermatozoa by the ovum of the domestic fowl, Gallus gallus at the time of fertilization (1980)
    Springer
    Cell & tissue research 206 (1980), S. 55-63 
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    ISSN: 1432-0878
    Keywords: Phagocytosis ; Spermatozoa ; Ovum ; Fertilization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Spermatozoa with intact acrosomes, as well as those coming into contact with the ovum at a smaller angle, and morphologically abnormal spermatozoa reach the plasma membrane of the ovum via an extensively dissolved zone of the inner layer of the vitelline membrane. This zone is assumed to be formed by overlapping of two or more tunnels formed by spermatozoa that had previously come into contact with the ovum. When a spermatozoon comes into contact with the plasma membrane of the ovum, many cytoplasmic processes extend outwards and cover it. Thereafter, the plasma membranes of the processes fuse, thereby phagocytizing the spermatozoon. It is assumed that the phagocytized spermatozoa cannot undergo transformation into male pronuclei and that they degenerate soon after phagocytosis.
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    Ca++-induced structural changes in photoreceptor microvilli of diptera (1980)
    Springer
    Cell & tissue research 206 (1980), S. 225-232 
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    ISSN: 1432-0878
    Keywords: Compound eye ; Photoreceptor membrane ; Electron microscopy ; Calcium-induced changes ; Artefacts ; Diptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When the compound eyes of the fly Lucilia are fixed for electron microscopy with glutaraldehyde in common buffer solutions, artefactual whorls are liable to be formed from the photoreceptor microvilli. The whorls result from two factors: (i) a prolonged time interval prior to osmication, such as the “overnight” primary fixation or wash at 4° C commonly used in studies of compound eyes; (ii) as little as 1–2 mM Ca++ in the primary fixative and wash solutions. Osmication after short (1 h) glutaraldehyde fixation at 4° C, or omission of Ca++ and addition of 2 mM EGTA, prevent whorl-formation. In the tipulid fly Ptilogyna, similar artefacts are produced, but are confined to the distal zone of the microvilli that sheds during turnover.
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    Scanning and transmission electron microscopic observations of the cloacal epithelia of the domestic fowl (1980)
    Springer
    Cell & tissue research 211 (1980), S. 83-93 
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    ISSN: 1432-0878
    Keywords: Epithelium ; Cloaca ; Electron microscopy ; Hen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithela of the three divisions (coprodaeum, urodaeum, proctodaeum) of the cloaca of the hen, and of the excretory ducts (colon, ureter, vagina) which join the divisions, are described using light microscopy, and scanning and transmission electron microscopy. Each region of the cloaca has its typical epithelium. Special attention is focussed in this study on the boundaries between the different epithelia. The coprodaeal epithelium does not differ considerably from that of the colon; a transitional zone is not visible. Distinct border zones, however, are observed between the other regions (ureter — urodaeum; vagina — urodaeum and proctodaeum; urodaeum-proctodaeum; proctodaeum — cutis). Although the vaginal opening is generally thought to lie in the urodaeum, our investigations show that at the vaginal opening into the cloaca the ciliated epithelium changes, on one border to a secretory epithelium characteristic of the urodaeum and on the other border to that characteristic of the proctodaeum. These observations are discussed in relation to functional aspects.
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    Ultrastructural alterations of the pancreatic D cell in the domestic fowl following vagotomy (1980)
    Springer
    Cell & tissue research 211 (1980), S. 171-174 
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    ISSN: 1432-0878
    Keywords: Pancreatic D cell ; Neural control ; Vagotomy ; Electron microscopy ; Fowl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an attempt to determine the neural control of pancreatic D cells, the pancreatic islets of the domestic fowl were examined electron microscopically from 1 to 28 days after abdominal vagotomy. Exocytotic release of many secretory granules from D cells occurred one day after vagotomy. Rough endoplasmic reticulum developed and formed an arrangement of concentric whorls in the cytoplasm of D cells after axotomy. The altered D cells were also characterized by the occurrence of many peculiar dense bodies in the apical cytoplasm at all time periods studied. These bodies varied in shape and size, containing several round vesicles. The D cells were extensively depleted of granules after the longer time periods following vagotomy. The present results provide new morphological evidence for the vagus-nerve control of D cells, which may regulate the activity of islet cells.
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    Fetal hypothalamic transplants in the third ventricle of the adult rat brain (1980)
    Springer
    Cell & tissue research 211 (1980), S. 191-206 
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    ISSN: 1432-0878
    Keywords: Hypothalamus ; Transplants ; Vasopressin ; Median eminence ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Blocks of anterior hypothalamus were transplanted from 19 day-old fetuses of Wistar/Lewis rats into the third ventricle of adult male Brattleboro rats. Physiological changes in graft recipients and in sham-operated animals were monitored daily. Twenty days after surgery, the graft recipients and shamoperated animals were killed and their brains examined by correlative scanning and transmission electron microscopy. Host animals that exhibited both decreased polydipsia and increased urine concentration were found to have viable grafts within the third ventricle. The observed physiological changes suggested that synthesis and release of vasopressin occurred in the transplanted neurons. Grafts were well vascularized by vessels arising from the host hypothalamus. Neurons, with perikarya ranging from 8 to 30 μm in diameter, glial cells, and neurites were located throughout the transplants. A neurohemal contact zone, similar to that normally seen in the median eminence, could not be demonstrated in the grafts. The absence of complete glial and ependymal barriers indicates a relatively close association between cells in the transplants and the cerebrospinal fluid. A large increase in supraependymal neurons and their processes, including an eruption of neurons through the floor of the third ventricle in one animal, was observed in graft recipients but not in shamoperated animals.
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    Fine structure of ependymal cysts in and around the area postrema of the rat (1980)
    Springer
    Cell & tissue research 206 (1980), S. 303-318 
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    ISSN: 1432-0878
    Keywords: Area postrema, rat ; Ependyma ; Cyst ; Circumventricular organs ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Peculiar cells forming cysts were observed in the area postrema and sometimes also in the choroid plexus and the tela chorioidea near the area postrema, and were studied in detail by electron microscopy. The cytological features of the cyst cell and its junctional relationship to neighboring cells imply that cyst cells are derived from ependymal and choroid epithelial cells. The cyst cells usually contact directly the perivascular spaces of postremal, choroidal or pial capillaries, where the cytoplasm is often considerably attenuated. The cystic lumen is commonly filled with a flocculent material. The limiting membrane of the cystic lumen, which frequently bears cilia and microvilli, has the same thickness as the surface cell membrane. In many cases, the cyst is surrounded by the cytoplasm of a single cell. In some cases, however, two cells participate in the formation of the cyst, although one is only a slender process and joined by a zonula occludens with the main cyst cell. Horseradish peroxidase (HRP) injected into the cerebrospinal fluid (CSF) space failed to enter the cystic lumen. A possible significance of the cyst in relation to the CSF and blood circulation was considered.
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    Incorporation of 3H-oleic acid by the proximal convoluted tubule cells of the chick (Gallus domesticus) (1980)
    Springer
    Cell & tissue research 210 (1980), S. 447-459 
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    ISSN: 1432-0878
    Keywords: Lipid ; Kidney tubules, proximal ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Lipid metabolism in the cells of the renal proximal convoluted tubules (PCT) was investigated in healthy fowls and in fowls with the Fatty Liver and Kidney Syndrome (FLKS). The tissue was fixed at 10–25 min intervals after intravenous injection of 3H-oleic acid. The distribution of autoradiographic grains was analysed by the “circle method”. In normal cells most of the silver grains were associated with the cytoplasmic organelles. Lipid droplets and Golgi elements had the highest specific activity relative to the nuclear activity, which was little above background level. Lysosome-like bodies and mitochondria had lower values. In the cells of the FLKS-affected birds a large proportion of the grains was located over the lipid droplets, which are abundant in this condition. The specific activity of the cytoplasmic organelles was barely 2-fold higher than the nuclear activity. The results suggest that there is a diminished incorporation of esterified fatty acids by the organelles of these cells and that the excess is transferred to the lipid droplets. The identity of low electron density particles observed in the PCT cells of severely affected birds is discussed.
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    Gut hormones in Salamandra salamandra (1980)
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    Cell & tissue research 211 (1980), S. 331-343 
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    ISSN: 1432-0878
    Keywords: Gut hormones ; Endocrine cells ; Electron microscopy ; Immunocytochemistry ; Peptidergic innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histological, cytochemical and immunocytochemical methods were used in light and electron microscopical studies to demonstrate the presence of a neuroendocrine system in the gut of the urodele, Salamandra salamandra. Cytochemical stains capable of detecting peptide-producing endocrine cells demonstrate cells reacting with Masson's silver (argentaffin) method, Grimelius' argyrophil silver method, masked metachromasia method and the lead haematoxylin stain. Using antisera raised to a variety of mammalian gut peptides, cells containing bombesin-, gastrin-, somatostatin-, substance P- and glucagon-like immunoreactivity were identified; vasoactive intestinal polypeptide- and substance P-like immunoreactivities were found in nerve fibres in the submucous and myenteric plexus. No immunoreactivity was detected for motilin, gastric inhibitory polypeptide, cholecystokinin or secretin. The ultrastructure of the immunoreactive cells and nerves was revealed by the semithin/thin method. All the cells identified contained numerous electrondense secretory granules, which varied in their chracteristic morphological structure from one cell type to another. The evidence collected in this study indicates that a complex neuroendocrine system regulating gut function is present in this amphibian and may have developed prior to the emergence of the phylum.
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    Monoaminergic neurons of the mudpuppy retina (1980)
    Springer
    Cell & tissue research 210 (1980), S. 269-282 
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    ISSN: 1432-0878
    Keywords: Monoaminergic neurons ; Retina ; Amacrine cells ; Neurotoxins ; Mudpuppy, Necturus maculosus ; Neurotransmitters ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The mudpuppy retina was investigated with the histofluorescence method of Falck and Hillarp in normal animals and in animals injected intraocularly with α-methylnoradrenaline, 5,6-dihydroxytryptamine, or a combination of the two drugs. Catecholaminergic amacrine cells were found to form a thin layer of terminals at the border between the inner nuclear and the inner plexiform layers. Catecholaminergic interplexiform cells were not found. Indoleamine-accumulating amacrine cells were also observed. They are fifteen to twenty times more numerous than the catecholaminergic cells, and their terminals occur diffusely throughout the inner plexiform layer. In a number of eyes the majority of the indoleamine-accumulating terminals were eliminated with intraocular injections of the neurotoxin, 5,7-dihydroxytryptamine, but the reproducibility of this effect was not consistent. Intravitreal injections of 5,6-dihydroxytryptamine were used to label both types of neurons for electron microscopy. They were found to make conventional type synapses on amacrine cells and, less frequently, on bipolar cells.
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    Merkel cells and nerve endings in the labial epidermis of a lizard (1980)
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    Cell & tissue research 210 (1980), S. 353-357 
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    ISSN: 1432-0878
    Keywords: Merkel cells (reptiles) ; Epidermis ; Lizard ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Examination of the labial epidermis of the lizard Lacerta sicula revealed cells displaying all features of Merkel cells. These cells are located in the stratum basale of epidermal pegs and are arranged in clusters.
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    Ultrastructural changes in Paneth cells during hibernation in the ground squirrel Spermophilm lateralis (1980)
    Springer
    Cell & tissue research 211 (1980), S. 293-301 
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    ISSN: 1432-0878
    Keywords: Paneth cell ; Hibernation ; Intestine ; Hypothermia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Paneth cells from jejuno-ileal segments of the small intestine of the ground squirrel, S. lateralis, was examined under normal euthermic conditions and during the profoundly depressed metabolic conditions of natural hibernation. Paneth cells obtained from hibernating animals gave evidence of markedly reduced activity when compared to Paneth cells from euthermic animals. In hibernating animals, the nuclei were smaller, with less prominent nucleoli and with an increased proportion of heterochromatin. In hibernating animals, the rough endoplasmic reticulum was fragmentary and poorly organized, in contrast to the typical arrangement of concentric lamellae seen in euthermic animals. Although the total number of ribosomes was decreased in hibernating animals, there were proportionally more free ribosomes than in euthermic animals. Paneth cells from hibernating animals also contained a greater number of apical secretory granules which were smaller and more variable in electron density than granules from control animals. These ultrastructural features indicate that during hibernation the Paneth cell is relatively quiescent.
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    Effect of testosterone on the female hamster harderian gland pigmentation and ultrastructure (1980)
    Springer
    Cell & tissue research 207 (1980), S. 511-517 
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    ISSN: 1432-0878
    Keywords: Female hamster ; Harderian gland ; Testosterone ; Tubular clusters ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Distinct differences occur in the pigmentation and ultrastructural features of the Harderian glands in male and female hamsters. The results of a study on the effect of testosterone on the fine structure of the female Harderian glands are presented here. Glands from three groups of hamsters were examined at intervals up to 49 days: (1) testosterone injected, receiving 2mg testosterone propionate in 0.1 ml sesame oil per day; (2) sham-injected, receiving 0.1 ml sesame oil per day; (3) untreated controls. Testosterone injections caused a reduction in the number of dark-brown pigment granules in the acinar cells starting on the 6th day, whereas clusters of tubules, typical of adult male glands, appeared on the 4th day and increased in number thereafter. Lamellar structures, normally present in the female gland, decreased in testosterone treated specimens. These changes reversed after cessation of testosterone treatment. It is concluded that exogenous testosterone administered to female hamsters modifies the pigmentation and ultrastructure of their Harderian glands towards the male type and that this is a reversable phenomenon. There also appears to be an inverse relationship between the presence of tubular clusters in the acinar cells, and the degree of pigmentation.
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    Microtubules, dendritic spines and spine apparatuses (1980)
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    Cell & tissue research 208 (1980), S. 171-181 
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    ISSN: 1432-0878
    Keywords: Microtubules ; Dendritic spine apparatus ; Synapse ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using techniques for enhanced microtubular preservation, including albumin pretreatment (Gray, 1975), occipital cortex of rats was studied electron microscopically at various ages of development. A close structural relationship was seen between microtubules, sacs of SER and the postsynaptic “thickening” in primordial spines and with the dense “plate” material of spine apparatuses. Stereoscopic preparations in addition show a more complicated substructure than previously described for the “plate”. Microtubules may contribute to the formation of the “plate” of the spine apparatus which in turn is associated with the postsynaptic “thickening” of the mature spine. Possible functional correlates are discussed.
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    Survival of satellite cells following exposure to the local anesthetic bupivacaine (Marcaine) (1980)
    Springer
    Cell & tissue research 209 (1980), S. 131-135 
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    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Bupivacaine ; Degeneration ; Satellite cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat lumbrical muscles were incubated in a concentration of 10-2 M bupivacaine for 5 or 15 min and examined after further incubation in the absence of the drug for periods totalling 1, 2, and 3h. Electron microscopy showed that muscle fibers and their component organelles and myonuclei underwent a series of irreversible degenerative changes. However, satellite cells retained their normal morphology under similar conditions. It is concluded that satellite cells are responsible for the rapid regeneration of muscles that follows degeneration induced by bupivacaine. The role of satellite cells in muscle regeneration is discussed.
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    URL: http://dx.doi.org/10.1007/BF00219929
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    Ultrastructural changes in the urophysis of Mollienesia sphenops following adaptation to seawater (1980)
    Springer
    Cell & tissue research 207 (1980), S. 135-142 
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    ISSN: 1432-0878
    Keywords: Caudal neurosecretory system ; Poeciliidae ; Electron microscopy ; Salinity changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The urophysis or neurohemal contact site of the caudal neurosecretory system of Mollienesia sphenops, the black molly, was studied in animals adapted to an artificial seawater environment. This species of fish was chosen for these studies because of its known ability to osmoregulate and its adaptability to the laboratory aquarium. The urophysis of freshwater acclimated mollys contained an abundance of neurosecretory granules. However, in fish subjected to a seawater environment for one week the number of neurosecretory granules was significantly decreased. In addition, there was an increase in blood cell infiltration of the urophysis.
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    Studies on the juxtaglomerular apparatus VI. Sympathetic innervation, catecholamines and the renin-angiotensin-system in rats and tree-shrews (Tupaia belangeri) (1980)
    Springer
    Cell & tissue research 212 (1980), S. 375-382 
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    ISSN: 1432-0878
    Keywords: Juxtaglomerular apparatus ; Sympathetic innervation ; Renin-angiotensin system ; Electron microscopy ; Fluorescence microscopy ; Tupaia belangeri ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary It has previously been reported that the primitive primate Tupaia belangeri develops a renal failure when exposed to psychosocial stress. In order to learn if this high susceptibility to stress of the Tupaia kidney can be correlated with morphological and functional parameters of the Juxtaglomerular apparatus (JGA) and the renin-angiotensin system, comparative experiments were performed on Tupaia and rat. Our results reveal an outstandingly high potency of the JGA and the renin-angiotensin system in Tupaia as evident from the following findings: The Tupaia JGA contains a great number of epithelioid cells abounding in renin granules (electron microscopy). The renin content of the Tupaia kidney is considerably higher than in the rat (radio-immunoassay). The sympathetic innervation of the kidney and especially of the JGA is abundant in Tupaia (fluorescence and electron microscopy). Catecholamine contents of the kidney and other organs are significantly higher in Tupaia than in rats (spectrophotofluorometry). Our results support the previously developed concept of a potent intrarenal neuroendocrine interaction at the JGA level favouring, under certain conditions of social stress, the development of acute renal failure in Tupaia belangeri.
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    URL: http://dx.doi.org/10.1007/BF00236504
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    Electron microscopic study of the paracortical postcapillary “high endothelial venules” in lymph nodes of the normal calf (1980)
    Springer
    Cell & tissue research 212 (1980), S. 465-474 
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    ISSN: 1432-0878
    Keywords: Postcapillary venules ; Calf ; Lymph nodes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the postcapillary “high endothelial venules” (HEV) of lymph nodes in calves was studied light and electron microscopically. These venules were detected light microscopically in the paracortical zone by their high cuboidal endothelium, a distinct basal lamina, the migration of lymphocytes through the vessel wall, and the dominance of lymphoid cells in the lumen, often completely obliterating the latter. Ultrastructurally, the endothelial cells (HEC) of the HEV were characterized by a prominent Golgi complex including many small vesicles, a few lysosome-like bodies, and a specific association between mitochondria and rough endoplasmic reticulum (MER). The HEC are connected by desmosomes, whereas the intimate contact points between migrating lymphocytes and endothelial cells could not be classified according to the well-defined junctional types. Lymphocyte migration occurred predominantly intercellularly, i.e., between endothelial cells. Although the overall appearance of the described vessel type in bovines bears resemblance to HEV in other investigated species, several differences occur that most probably are related to species variation.
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    Mutant fs(1) 1163 of Drosophila melanogaster alters yolk protein secretion from the fat body (1980)
    Springer
    Molecular genetics and genomics 180 (1980), S. 411-418 
    Details
    ISSN: 1617-4623
    Keywords: Drosophila ; Vitellogenin ; Female-sterile mutant ; Protein processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The mutant fs(1) 1163 of Drosophila melanogaster, which was isolated by Gans et al. (1975) is a recessive homozygous female sterile at 18°C and a dominant female — sterile at 29°C. We reported previously that there are reduced quantities of the largest of the three yolk polypeptides in Drosophila melanogaster in the haemolymph and eggs of this mutant at 29°C (Bownes and Hames 1978 a). In this paper we show that the yolk protein defect maps within approximately 2.5 recombination units of the female sterility at 21±2.5 map units on the X-chromosome. The temperature-sensitive period of the yolk protein defect is after emergence. In vitro labelling of fs(1) 1163 ovaries and fat bodies showed that they were able to synthesise yolk polypeptide 1. Interestingly, studies on the proteins present in the various tissues indicate that the fat body tends to accumulate all three yolk polypeptides in the mutant. This phenotype is partially co-dominant in that an effect is seen in heterozygotes as well as homozygotes and is enhanced by increased temperature. This mutant could therefore have a defect (a) in the structural gene for yolk polypeptide 1, (b) in the processing and secretion enzyme systems; (c) in the fat body or all tissues leading to altered secretion properties. Mutants like fs(1) 1163 which alter specific steps in vitellogenesis should be of value for analysing the genetic and biochemical control of the synthesis, transport and sequestering of the yolk polypeptides during oogenesis.
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    Relationship between ADH activity and behavioral response to environmental alcohol inDrosophila (1980)
    Springer
    Behavior genetics 10 (1980), S. 237-249 
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    ISSN: 1573-3297
    Keywords: Drosophila ; behavior ; ADH activity ; adaptation ; evolution ; alcohol avoidance ; Adh genotypes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Three alcohol dehydrogenase genotypes, homozygous for either the electrophoretically fast, slow, or null allele at theAdh locus inD. melanogaster, were tested for relative larval alcohol preference behavior (APB) over a range of ethanol concentrations. Differences in behavior between genotypes were not significant at concentrations below 10%. At concentrations greater than 10%, avoidance behavior was negatively correlated with the relative ADH activity levels of the genotypes tested. A model based on the differential buildup of toxic acetaldehyde is proposed to explain the avoidance response.
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    Some observations onHaemohormidium cotti Henry 1910, from the marine fishCottus bubalis euphrasen (1980)
    Springer
    Parasitology research 62 (1980), S. 31-38 
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    ISSN: 1432-1955
    Keywords: Haemohormidium cotti ; Light microscopy ; Electron microscopy ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Haemohormidium cotti, an organism of uncertain status, is redescribed from one of its type hosts, the marine fish,Cottus bubalis. The parasite occurs as irregularly round, oval, or elongate, intraerythrocytic bodies within blood and tissue preparations. Electron micrographs show features which suggest thatH. cotti may, as previously suspected, belong with the Piroplasmasida but no firm evidence of this is established. Possible division stages are identified in both light and electron micrographs. The taxonomic position ofHaemohormidium is discussed.
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    Babesia microti (Apicomplexa: Piroplasmida): Electron microscope detection in salivary glands of the tick vectorIxodes ricinus (Ixodoidea: Ixodidae) (1980)
    Springer
    Parasitology research 64 (1980), S. 113-115 
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    ISSN: 1432-1955
    Keywords: Babesia microti ; Electron microscopy ; Ticks ; Ixodes ricinus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1007/BF00927061
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    Pancreatic polypeptide (PP)- and glucagon cells in the pancreatic islet of Xiphophorus helleri h. (Teleostei) (1980)
    Springer
    Cell & tissue research 205 (1980), S. 187-198 
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    ISSN: 1432-0878
    Keywords: Pancreatic polypeptide (PP) ; Glucagon ; Pancreatic islet ; Xiphophorus helleri ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'étude immunohistochimique de l'îlot pancréatique du poisson téléostéen Xiphophorus helleri, à l'aide de sérums anti-polypeptide pancréatique (PP) et anti-glucagon a permis de montrer que deux populations cellulaires distinctes sont responsables de la sécrétion de ces hormones. L'observation comparée de coupes sériées, ultrafines et semifines, traitées par la technique immunohistochimique, a démontré que les cellules à PP correspondent aux cellules qui avaient été précédemment définies, dans cette espèce, comme “cellules A2 à grains ronds” et que les cellules sécrétrices de glucagon sont les “cellules A2 à grains cristallins”. L'hypothèse de l'existence de deux catégories de cellules à glucagon chez les téléostéens est abandonnée.
    Notes: Summary Correlative immunohistochemical and electron microscopical studies on the pancreatic islet of the teleost fish Xiphophorus helleri using antibodies to pancreatic polypeptide (PP) and glucagon show that separate cell types are responsible for the production of these peptides. The PP-cells correspond to the previously described “A2-cells with round granules”, while the “A2-cells with crystalline granules” are the true glucagon cells. An earlier suggestion that there are two types of glucagon cells in teleost islets is therefore withdrawn.
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    The number and arrangement of elements in the lamina cartridge of the dragonfly Sympetrum rubicundulum (1980)
    Springer
    Cell & tissue research 206 (1980), S. 395-401 
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    ISSN: 1432-0878
    Keywords: Dragonfly visual system ; Lamina ganglionaris ; Monopolar cells ; Optic neuropile ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Five monopolar cells and two long visual fibres are a consistent component of the lamina cartridge of the ventral half of the eye of the dragonfly Sympetrum rubicundulum. They communicate with the chiasm via a cartridge axon bundle comprising a minimum of ten fibres. The arrangement of these elements is documented with respect to the ommatidial photoreceptor axon bundle innervating them. These relationships are described both within the lamina cortex and in the cross-section of the underlying cartridge.
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    Lactate sensitive cells in newt kidneys (1980)
    Springer
    Cell & tissue research 207 (1980), S. 233-239 
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    ISSN: 1432-0878
    Keywords: Kidney ; Triturus cristatus carnifex ; Erythropoiesis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Specimens of Triturus cristatus carnifex (Laurenti), raised in 3.2 g/l solution of sodium lactate, presented hypertrophy of “lactate sensitive cells” (LSC) clustered at the vascular pole of each renal corpuscle. As seen under both the light and electron microscopes, these are specialized cells of the Bowman's capsule located at the junction between its visceral and parietal layers. The structure formed by the cells, heretofore unknown, is topographically associated with the juxtaglomerular apparatus. As lactate stimulates erythropoiesis even in normal oxygenated specimens and hypoxia induces hypertrophy of LSC in newts, it is hypothesized that the LSC are the site of erythropoietin (ESF) synthesis. A scheme of ESF biogenesis in newts, integrating the above principles, concludes the paper.
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    Ontogeny and organization of the stationary non-lymphoid cells in the human thymus (1980)
    Springer
    Cell & tissue research 207 (1980), S. 287-306 
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    ISSN: 1432-0878
    Keywords: Fetal human thymus ; Epithelial cells ; Development and differentiation ; Mesenchymal reticulum cells ; T lymphocytes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ontogenetic differentiation of the human thymus was investigated in 50 embryos by means of light and electron microscopic methods in an attempt to clarify the morphogenesis of the complicated microecology of thymic tissue. At the 8th gestational week (g.w.), the primordium of the thymus contains almost exclusively undifferentiated epithelial cells. At the 10th g.w., the epithelial cells in the central part are spindle-shaped. During the subsequent weeks the cortical region of the thymus becomes separated into lobes by mesenchymal septa containing hemopoietic precursor cells and large electronlucent cells with irregularly shaped nuclei. The latter cells are also found in the deeper presumptive medullary regions of the thymus; they differentiate into interdigitating reticulum cells (IDC). The permeation of the medulla of the thymus by non-epithelial IDC occurs concurrently with the formation of cortical and medullary epithelial cells. Between the 12th and 14th g.w. the cortical and medullary differentiation is completed. At this time-stage cortical small lymphocytes differ in morphological shape from medullary lymphocytes, the latter acquiring the appearance of immunocompetent T cells and establishing intimate contact with the IDC. These findings indicate that the thymic cortex and medulla contain different epithelial cells. In addition, the thymic medulla displays cells characterized by the morphology of typical interdigitating reticulum cells of peripheral lymphoid tissue. The structural pattern of the thymus is correlated to morphologically differing lymphoid cell populations in the cortical and medullary regions.
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    Scanning and transmission electron microscopic study of the supraependymal macrophages in the lateral ventricles of the toad brain (1980)
    Springer
    Cell & tissue research 207 (1980), S. 321-329 
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    ISSN: 1432-0878
    Keywords: Supraependymal cells ; Macrophages ; Electron microscopy ; Lateral ventricles ; Amphibian brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Transmission and scanning electron microscopy of the lateral ventricles of the toad brain revealed the presence of supraependymal cells that have the features of macrophages. Based solely on their surface morphology three different cell forms could be identified. The most frequently observed cells are flat and multipolar, and have a smooth or ruffled surface. The second type is spherical with a ruffled surface and occurs either singly, in which case it lacks processes, or in clusters from which processes radiate. The third type has surface blebs and numerous thin, smooth processes. However, when specimens that had been examined in the scanning electron microscope are viewed in the transmission electron microscope, all cells appear to belong to a single cell type. All cells viewed closely resemble macrophages in that they contain nuclei with clumped chromaffin, single cisternae of rough endoplasmic reticulum, numerous dense bodies, and many Golgi complexes. In addition, when horseradish peroxidase (HRP) was perfused into the ventricles, reaction product was found a short time thereafter within cytoplasmic vacuoles, and after a longer period within dense bodies. Because of their ultrastructural resemblance to macrophages and their capacity to ingest HRP, we suggest that these cells function as phagocytes and, as such, act to remove foreign materials from the cerebrospinal fluid.
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    Organ culture of the islets of Langerhans from young and senescent rats (1980)
    Springer
    Cell & tissue research 207 (1980), S. 429-448 
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    ISSN: 1432-0878
    Keywords: Islet of Langerhans ; Aging ; Insulin-secreting cells ; Organ culture ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The B-cells of the endocrine pancreas constitute an adequate model for in vitro study of the aging process in highly differentiated cells. In the present study, collagenase-isolated islets of Langerhans from young and senescent rats were cultured up to 28 days. The response of the B-cells to the stimulatory conditions of the culture medium involved the nucleus, ribosomes, endoplasmic reticulum, Golgi apparatus, and secretory granules. Correlated data from light microscopy, electron microscopy, and insulin radioimmunoassay show that the differentiation and function of senescent B-cells are maintained in culture, as it has been proven for the B-cells of younger animals. On the other hand, signs of cytological deficiency not directly concerned with the specific function of B-cells were observed: abnormal mitochondria and lysosomes are more numerous in the senescent B-cells. The proliferative capacity of the B-cells of aged rats is reduced.
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    An electron microscopic study of the salivary gland of Rhynchosciara angelae (1980)
    Springer
    Cell & tissue research 207 (1980), S. 449-461 
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    ISSN: 1432-0878
    Keywords: Rhynchosciara angelae ; Salivary gland ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the salivary gland of the dipteran insect Rhynchosciara angelae in a defined stage of the larval development, characterized by the synthesis and storage of secretion product, is described. Observations were made with both Nomarski optics and electron microscopy. Filiform projections extending into the lumen of the gland were observed in the apical portion of the cells. At the basal region junctions, characterized as hemidesmosomes, were observed between the membrane of the cell and the basal lamina. The plasma membrane presents numerous infoldings into the cell increasing considerably the surface area at this region. Throughout the cytoplasm of the gland cells numerous mitochondria, Golgi complexes, microtubules, profiles of endoplasmic reticulum, secretion granules and glycogen granules were observed. Carbohydrates were detected on ultrathin sections by using the periodic acid-silver methenamine and the periodic acid-thiosemicarbazide-silver proteinate techniques.
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    Fibre types in the locomotory muscles of an antarctic teleost, Notothenia rossii (1980)
    Springer
    Cell & tissue research 208 (1980), S. 143-164 
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    ISSN: 1432-0878
    Keywords: Locomotory muscle ; Fibre types ; Antarctic fish (Notothenia rossii) ; Histochemistry ; Electron microscopy ; Energy metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The metabolic and structural differentiation of locomotory muscles of Notothenia rossii has been investigated. In this species sustained locomotion is achieved by sculling with enlarged pectoral fins (labriform locomotion), whilst the segmental myotomal muscle is reserved for burst activity. Red, white and subepidermal fibres can be distinguished in the trunk by histochemical and ultrastructural criteria. The main pectoral muscle (m. adductor profundus) consists entirely of red fibres. These three main fibres types show differences in histochemical staining profiles, capillarization, myofibril shape and packing, and lipid and mitochondrial content. The fractional volume of mitochondria amounts to 38% for pectoral, 30% for red myotomal and 1.9% for white myotomal fibres. Enzyme activities of red pectoral muscle are consistent with a higher potential for aerobic glucose and fatty acid oxidation than for the red myotomal fibres. Mg2+ Ca2+ -myofibrillar ATPase activities are similar for red pectoral and myotomal muscles and approximately half of those white fibres. Specialisations of N. rossii muscles associated with labriform swimming and locomotion at Antarctic temperatures are discussed.
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    The fine structure of the stomach mucosa of the llama (Llama guanacoe) (1980)
    Springer
    Cell & tissue research 208 (1980), S. 207-228 
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    ISSN: 1432-0878
    Keywords: Hind stomach ; Fundic glands ; Electron microscopy ; Histochemistry ; Endocrine cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithelium of the fundic region mucosa of the hind stomach in the Llama guanacoe has been studied using morphological and histochemical methods. Morphology suggests that solute and water absorption may occur in the epithelium of the surface and of the foveolae, although this absorption can not be estimated because of the extensive secretion of the gastric glands. The same cells of the surface and foveolar epithelium show numerous secretory granules. The glands reveal neck cells, chief cells, a large number of oxyntic cells, four types of endocrine cells (A-like, ECL, D and EC), brush cells and wandering cells. PAS and Alcian blue reactions for light microscopy suggest a secretion of neutral and acidic mucosubstances in the surface and foveolar epithelium, of neutral mucosubstances only in the neck cells. Periodic acid-thiocarbohydrazide silver proteinate (PA-TCH-SP) reaction for electron microscopy confirms the presence of neutral mucosubstances within the secretory granules of the surface, foveolar and neck epithelial cells. In all these cells, the reaction product is also evident within sacculi and vesicles of the maturing surface of the Golgi apparatus. A positive PA-TCH-SP reaction also occurs on the membrane (and not on the contents) of the Golgi apparatus (maturing surface) and of the secretory granules of the chief cells as well as on the membrane of the Golgi apparatus and of apical vesicles and tubules of the oxyntic cells. In addition, silver granules slightly enhance the electron density of the contents of the secretory granules in the endocrine cells. Morphological and histochemical findings are discussed and compared with results described by others for monogastric mammals.
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    The synaptic organization of visual interneurons in the lobula complex of flies (1980)
    Springer
    Cell & tissue research 208 (1980), S. 371-387 
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    ISSN: 1432-0878
    Keywords: Lobula complex ; Visual interneurons ; Ultrastructure ; Cobalt-impregnations ; Electron microscopy ; Diptera (Calliphora erythrocephala)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The synaptic organization of three classes of cobalt-filled and silver-intensified visual interneurons in the lobula complex of the blowfly Calliphora (Col A cells, horizontal cells and vertical cells) was studied electron microscopically. The Col A cells are regularly spaced, columnar, small field neurons of the lobula, which constitute a plexus of arborizations at the posterior surface of the neuropil and the axons of which terminate in the ventrolateral protocerebrum. They show postsynaptic specializations in the distal layer of their lobula-arborizations and additional presynaptic sites in a more proximal layer; their axon terminals are presynaptic to large descending neurons projecting into the thoracic ganglion. The horizontal and vertical cells are giant tangential neurons, the arborizations of which cover the anterior and posterior surface of the lobula plate, respectively, and which terminate in the perioesophageal region of the protocerebrum. Both classes of these giant neurons were found to be postsynaptic in the lobula plate and pre- and postsynaptic at their axon terminals and axon collaterals. The significance of these findings with respect to the functional properties of the neurons investigated is discussed.
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    The pineal complex of the three-spined stickleback, Gasterosteus aculeatus L. (1980)
    Springer
    Cell & tissue research 209 (1980), S. 11-28 
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    ISSN: 1432-0878
    Keywords: Epiphysis cerebri ; Parapineal organ ; Fluorescence histochemistry ; Electron microscopy ; Gasterosteus aculeatus L ; Teleostei
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pineal complex of the three-spined stickleback (Gasterosteus aculeatus L.) was investigated by light and electron microscopy, as well as fluorescence histochemistry for demonstration of catecholamines and indolamines. The pineal complex of the stickleback consists of a pineal organ and a small parapineal organ situated on the left side of the pineal stalk. The pineal organ, including the entire stalk, is comprised mainly of ependymal-type interstitial cells and photoreceptor cells with well-developed outer segments. Both unmyelinated and myelinated nerve fibres are present in the pineal organ. Nerve tracts from the stalk enter the habenular and posterior commissures. A small bundle of nerve fibres connects the parapineal organ and the left habenular body. The presence of indolamines (5-HTP, 5-HT) was demonstrated in cell bodies of both the pineal body and the pineal stalk, and catecholaminergic nerve fibres surround the pineal complex.
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    Lipid droplets in the visceral yolk sac endodermal cells of the postimplantation rat embryo: Application of malachite green-glutaraldehyde fixative (1980)
    Springer
    Cell & tissue research 209 (1980), S. 29-41 
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    ISSN: 1432-0878
    Keywords: Visceral yolk sac ; Lipid droplets ; Malachite green-glutaraldehyde fixative ; Rat embryo ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the visceral yolk sac (VYS) of the rat embryo at day 9.5 of gestation was examined after fixation with either Karnovsky's glutaraldehyde-paraformaldehyde solution or malachite green-containing glutaraldehyde (MGA) solution. Fixation with MGA retained homogeneously electron-dense droplets in the cytoplasm and the nucleus of endodermal cells, both of which were lost in the specimens prepared by Karnovsky's fixation method. The cytoplasmic MGA-positive droplets were frequently associated with other cytoplasmic organelles such as rough endoplasmic reticulum, mitochondria and membrane-delineated inclusion bodies, but these cytoplasmic organelles never incorporated MGA-positive materials, whereas Golgi apparatus contained intracisternal MGA-positive droplets. Extracellular MGA-positive droplets were also encountered at the apical surface of endodermal cells and in the intercellular space between endodermal cells and the underlying mesodermal cells. These MGA-positive droplets were considered to be lipid in nature, and their origin in the endodermal cells of VYS is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219920
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    Hypothalamo-hypophysial function following the lesion of tanycytes in the median eminence of the rat (1980)
    Springer
    Cell & tissue research 209 (1980), S. 225-238 
    Details
    ISSN: 1432-0878
    Keywords: Tanycytes ; Median eminence ; Electron microscopy ; Rat ; Serum LH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The transport of hormones from the cerebrospinal fluid to the adenohypophysis by the tanycytes of the median eminence was examined in male rats. Electron microscopy revealed that all ependymal cells including the tanycytes disappear or degenerate in rats subjected to electric cauterization of the ependymal layer lining the third ventricle. However, the granular axons in the palisade layer of the median eminence remain intact. In rats subjected to electric lesion, no significant change was found in either the serum-LH level or in the weight of the adenohypophysis, testes, adrenal and thyroid glands. It is concluded that the tanycytes do not participate in the hypothalamic regulation of hypophysial function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237628
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    Induction of intranuclear microtubules in chick embryo fibroblasts by frog virus 3 (1980)
    Springer
    Cell & tissue research 209 (1980), S. 271-277 
    Details
    ISSN: 1432-0878
    Keywords: Intranuclear microtubules ; Chick embryo fibroblasts ; Frog Virus 3 ; Electron microscopy ; Tubulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intranuclear microtubules appear in chick embryo fibroblasts upon infection with Frog Virus 3 (FV 3). Both the diameter and the annular shape of the microtubule profiles, established from electron microscopic observations using a goniometer, suggest that they are identical to naturally occurring cytoplasmic microtubules. Furthermore, the use of vinblastine allowed demonstration of the tubulin composition of the intranuclear microtubules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237631
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    The origin of the dendritic reticulum cell (1980)
    Springer
    Cell & tissue research 209 (1980), S. 279-294 
    Details
    ISSN: 1432-0878
    Keywords: Germinal center reaction ; Dendritic reticulum cell ; Rabbit spleen ; Enzyme histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To obtain more information concerning the origin of dendritic reticulum cells, the development of germinal centers in the spleens of rabbits was investigated by conventional light microscopy, enzyme histochemistry, and electron microscopy. Washed sheep erythrocytes were used as antigen. Splenic tissue was examined on the 13th, 18th, 21st, 27th and 48th day after antigen administration. Electron microscopic investigations revealed transitional forms between typical fibroblastic reticulum cells, which formed the framework of the entire splenic white pulp, and typical dendritic reticulum cells. During this transformation, the enzyme histochemical pattern of alkaline phosphatase disappeared and a positive alpha-naphthyl acetate esterase reaction appeared in the transformed cells. On the basis of these findings, it is highly likely that dendritic reticulum cells develop through transformation of fibroblastic reticulum cells during the development of germinal centers in rabbit spleens. The characteristic folding of the surface membrane of dendritic reticulum cells is probably caused by the conspicuous increase in size of the Golgi apparatus, the detachment of vesicles, and the uptake of such vesicles by the cell membrane observed electron microscopically during the cellular transformation. Receptors that are of significance in antigen trapping might reach the cell surface in this manner, i.e., with the Golgi vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237632
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    Mapping stimulus-induced nervous activity in small brains by [3H]2-deoxy-D-glucose (1980)
    Springer
    Cell & tissue research 211 (1980), S. 51-64 
    Details
    ISSN: 1432-0878
    Keywords: Cerebral glucose utilization ; Deoxyglucose method ; Dry autoradiography ; Insect brain ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Nervous activity may be localized in anatomical sections of brain tissue by the autoradiographic deoxyglucose technique. The method provides sufficient structural preservation and spatial resolution for detailed functional investigation of complex but small-sized nervous systems when the original technique is modified as follows: (i) use of 3H instead of 14C as radioactive label, (ii) application of labeled deoxyglucose in concentrations close to physiological glucose levels rather than in trace amounts, (iii) stimulation for 4–9 h after deoxyglucose application instead of 20–45 min, (iv) subsequent preparation avoiding aqueous phases at all stages from fixation to autoradiography, and (v) plastic embedding of the tissue such that serial semithin sections of good structural preservation may be routinely cut. Brief aqueous fixation and dehydration at room temperature as has been described for vertebrates apparently cannot preserve stimulus-induced distribution of radioactive label in the brain of the fly Drosophila melanogaster. Aspects of the results that illustrate the potential and some limitations of the present technique are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233722
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    Dense material associated with apparent presynaptic elements in cell cultures of the CNS (1980)
    Springer
    Cell & tissue research 211 (1980), S. 95-103 
    Details
    ISSN: 1432-0878
    Keywords: Synapse ; Synaptogenesis ; Cell culture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In cell cultures of the rat cerebellum, electron-dense material has been found occasionally between adjacent cells. More often than not, presynaptic elements on one side of the dense material faced either neuronal or nonneuronal cells on the other side. The 20 nm thick material was stained either with the osmium-uranyl-lead (OsUL) procedure or with the ethanolic phosphotungstic acid (E-PTA) procedure. To determine the source of the dense material, various compounds were added to cultures at 7 days in vitro. Only a crude nuclear fraction was able to duplicate the appearance of the dense material associated with the apparent presynaptic elements. It was concluded that apparent presynaptic elements were associated with the polybasic dense material and that this type of association may duplicate an interaction in the normal development of synaptic contacts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233726
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    The tight junctions of renal tubules in the cortex and outer medulla (1980)
    Springer
    Cell & tissue research 212 (1980), S. 395-413 
    Details
    ISSN: 1432-0878
    Keywords: Kidney ; Distal tubule ; Collecting duct ; Electron microscopy ; Thin sections ; Freeze fracturing ; Tight junctions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Quantitative aspects of tight junction morphology were systematically studied in the cortical and outer medullary segments of the distal urinary tubules of rat, hamster, rabbit, cat, dog and the primitve primate Tupaia belangeri. Only minor differences in junctional architecture were found between straight and convoluted portions of the distal tubule. In contrast, the collecting duct in cortex and outer medulla, in all species, exhibits the most elaborate tight junctions observed along the uriniferous tubule. The present and previous findings from this laboratory indicate that increasing “tightness” of the junctional complexes is apparent along the course of the nephron in all species studied. The proposed relationship between quantitative aspects of the zonula occludens and presently available values for transepithelial electrical resistance was re-examined for the renal tubules. It was found that for the mammalian kidney a satisfactory correlation exists between the tight junction morphology and presently known functional parameters. This relationship is the more evident the more additional dimensional characteristics of the intercellular clefts are taken into consideration. It may therefore be concluded that, at least for the mammalian kidney, the assumption of differences in the molecular organization of the tight junctions is not needed to explain so far unresolved discrepancies between tubular morphology and function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236506
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    An electron microscopic study on stellate cells in the rabbit adenohypophysis under various endocrine conditions (1980)
    Springer
    Cell & tissue research 213 (1980), S. 237-246 
    Details
    ISSN: 1432-0878
    Keywords: Stellate cell ; Nongranulated cell ; Adenohypophysis ; Rabbit ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Stellate cells in the rabbit adenohypophysis were observed electron microscopically under normal and experimental conditions such as lactation, thyroidectomy, adrenalectomy, or castration. In control animals stellate cells had a scanty cytoplasm surrounding the nucleus and possessed slender processes extending between granulated cells. The processes were interconnected by desmosomes to form a meshwork. In the cytoplasm, abundant microfilaments were present as well as ill-developed ordinary cell organelles, but secretory granules were absent. In the adenohypophysis of experimental groups, in which the granulated cells underwent characteristic changes, stellate cells also showed remarkable morphological alterations which were similar in all groups. In general, they became hypertrophied, and contained a well-developed Golgi apparatus and rough-surfaced endoplasmic reticulum. Lysosomes or lipid droplets were frequently encountered. Between adjacent stellate cells, intercellular canals were markedly developed and many microvilli were noticed. Based on the above data, it is suggested that the stellate cells are not only sustentacular elements, but play an important role in the function of the adenohypophysis, such as the supply of materials to granulated cells or the disposal of waste products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234784
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    The programming of silk-gland development in Bombyx mori (1980)
    Springer
    Cell & tissue research 213 (1980), S. 311-324 
    Details
    ISSN: 1432-0878
    Keywords: Bombyx ; Silk-gland ; Starvation ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cytological development of the silk gland has been studied by light and electron microscopy in silkworms experimentally starved at different periods of the natural feeding stage during the fifth instar. When newly molted animals are not provided with food, no sign of growth is observed. Starvation initiated early during the obligatory feeding period, stops cell growth and development of the organelles involved in protein synthesis and secretion, whereas it induces the appearance of organelles concerned with autolysis. These effects are reversible if starvation is not prolonged beyond two days. Starvation during the facultative feeding period, at the time of massive fibroin production, results in quantitative and qualitative modifications of organelles related to the decrease of fibroin production and the onset of autolysis. Rough endoplasmic reticulum, responsible for fibroin synthesis, forms transitory whorls. Fibroin transport via the Golgi apparatus and secretion of the protein into the gland lumen decrease parallel to fibroin synthesis, so that no fibroin storage can be detected in any organelle. After food deprivation, autophagosomes and secondary lysosomes rapidly develop in the cytoplasm, and if starvation continues portions of the cytoplasm are sequestered and completely destroyed. If animals are refed, fibroin production is resumed and autolysis declines. These ultrastructural alterations of the silk gland during experimental starvation are very similar to those observed during the periods of physiological starvation (molt and cocoon spinning) and generally considered to be under hormonal control. Our results raise the question of the nature of interactions between alimentary and hormonal factors which control silk-gland development.
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    URL: http://dx.doi.org/10.1007/BF00234790
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