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  • Scanning electron microscopy  (77)
  • Drosophila melanogaster  (67)
  • Springer  (144)
  • Periodicals Archive Online (PAO)
  • 1975-1979  (144)
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  • 1
    Electronic Resource
    Electronic Resource
    Localization of cells capable of transdetermination in a specific region of the male foreleg disk ofDrosophila (1977)
    Springer
    Development genes and evolution 182 (1977), S. 69-74 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila melanogaster ; Male foreleg disk ; Capacity of transdetermination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the male foreleg disk ofDrosophila melanogaster the cells capable of transdetermination are clustered in a specific region within the upper half of the disk. Cells outside this region cannot transdetermine under any of the experimental conditions thus far applied. Transdetermination occurs when cells capable of transdetermination are stimulated to a certain extent of additional proliferation. This can be achieved either by exposing these cells at a wound surface of an intact fragment, or by dissociation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848088
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  • 2
    Electronic Resource
    Electronic Resource
    Localized synthesis of specific proteins during oogenesis and early embryogenesis inDrosophila melanogaster (1979)
    Springer
    Development genes and evolution 187 (1979), S. 151-165 
    Details
    ISSN: 1432-041X
    Keywords: Oogenesis ; Embryogenesis ; Two-dimensional gels ; Protein synthesis ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Protein synthesis in egg follicles and blastoderm embryos ofDrosophila melanogaster has been studied by means of two-dimensional gel electrophoresis. Up to 400 polypeptide spots have been resolved on autoradiographs. Stage 10 follicles (for stages see King, 1970) were labelled in vitro for 10 to 60 min with35S-methionine and cut with tungsten needles into an anterior fragment containing the nurse cells and a posterior fragment containing the oocyte and follicle cells. The nurse cells were found to synthesize a complex pattern of proteins. At least two proteins were detected only in nurse cells but not in the oocyte even after a one hour labelling period. Nurse cells isolated from stages 9, 10 and 12 follicles were shown to synthesize stage specific patterns of proteins. Several proteins are synthesized in posterior fragments of stage 10 follicles but not in anterior fragments. These proteins are only found in follicle cells. No oocyte specific proteins have been detected. Striking differences between the protein patterns of anterior and posterior fragments persist until the nurse cells degenerate. In mature stage 14 follicles, labelled in vivo, no significant differences in the protein patterns of isolated anterior and posterior fragments could be detected; this may be due to technical limitations. At the blastoderm stage localized synthesis of specific proteins becomes detectable again. When blastoderm embryos, labelled in vivo, are cut with tungsten needles and the cells are isolated from anterior and posterior halves, differences become apparent. The pole cells located at the posterior pole are highly active in protein synthesis and contribute several specific proteins which are found exclusively in the posterior region of the embryo. In this study synthesis of specific proteins could only be demonstrated at those developmental stages which are characterized by the presence of different cell types within the egg chamber, while no differences were detected when stage 14 follicles were cut and anterior and posterior fragments analyzed separately. The differences in the pattern of protein synthesis by pole cells and blastoderm cells indicate that even the earliest stages of determination are reflected by marked changes at the biochemical level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848268
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  • 3
    Electronic Resource
    Electronic Resource
    Genetic analysis of pattern-formation in the embryo ofDrosophila melanogaster (1977)
    Springer
    Development genes and evolution 183 (1977), S. 249-268 
    Details
    ISSN: 1432-041X
    Keywords: Pattern-formation ; Embryogenesis ; Maternal-effect mutants ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The mutationbicaudal (Bull, 1966) causes embryos to develop a longitudinal mirror image duplication of the posteriormost abdominal segments, while head and thorax are missing. These embryos occur with varying frequencies among eggs laid by mutant females, irrespective of the paternal genotype. Recombination and deletion mapping indicate thatbicaudal (bic) is a recessive, hypomorphic, maternal-effect mutation mapping at a single locus on the second chromosome ofDrosophila melanogaster close tovg (67.0±0.1). The frequency of bicaudal embryos depends on the age of the mother, her genetic constitution and the temperature at which she is raised. Best producers are very young females hemizygous forbic (bic/Df(2)vg B ) at 28° C. Under these conditions 80% to 90% of the eggs which differentiate can show the bicaudal embryo phenotype. Upon ageing of the mother the frequency of bicaudal embryos declines rapidly, and most of the eggs develop the normal body pattern. Temperature shift experiments suggest a temperature-sensitive period at the onset of vitellogenesis. The mutation causes several types of abnormalities in the segment pattern of theDrosophila embryo, which are interpreted as various degrees of expression of the mutant character. The most frequent abnormal phenotype is the symmetrical bicaudal embryo with one to five abdominal segments duplicated. Less frequent are asymmetrical types, in which the smaller number of segments is always in the anterior reversed part. Other phenotypes are embryos with missing or rudimentary heads, and embryos with irregular gaps in the segment pattern. In bicaudal embryos, the pole cells, formed at the posterior pole of the egg prior to blastoderm formation, are not duplicated at the anterior. The significance of thebicaudal phenotypes for embryonic pattern-formation inDrosophila is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00867325
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  • 4
    Electronic Resource
    Electronic Resource
    Detection of clones in the nervous system ofDrosophila melanogaster (1977)
    Springer
    Development genes and evolution 183 (1977), S. 165-169 
    Details
    ISSN: 1432-041X
    Keywords: Clones ; Nervous system ; Shibire ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitotic recombination was induced, by X-irradiation at the blastoderm stage, in flies heterozygous for one of the temperature-sensitive paralytic mutationsshibire andtp-2. The results show that these mutations can be used to detect the presence of clones in the central nervous system through the temperature-sensitive paralysis of individual legs. Mitotic recombination can also be used to examine the effects of these mutations in the peripheral nervous system; shibire is thus shown to affect the function of sensory neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848786
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  • 5
    Electronic Resource
    Electronic Resource
    Isozymic patterns and functional states of cell lines ofDrosophila melanogaster cultured in vitro. II (1976)
    Springer
    Development genes and evolution 180 (1976), S. 107-119 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila melanogaster ; Cell lines ; Isoenzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Our previous isoenzyme investigation ofDrosophila melanogaster cell lines in vitro has been completed with twelve further enzyme systems. The “enzyme profiles” seem to be in good agreement with a previous hypothesis concerning the precise origin of these cell lines (probably from imaginal discs or nervous tissues). Our results have been summarized with reference to the biochemical genetic map ofDrosophila melanogaster in order to consider a possible functional organization of the genome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848101
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  • 6
    Electronic Resource
    Electronic Resource
    A study of the female germ line in mosaics ofDrosophila (1978)
    Springer
    Development genes and evolution 184 (1978), S. 41-56 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila melanogaster ; Female germ line ; Mosaics ; Stem cell divisions ; Metafemale ; Sterility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Our report presents an analysis of the development and dynamics of the female germ line inDrosophila. Females were produced that were mosaic either for attached-X chromosomes $$(\widehat{XX})$$ and a ring-X (triplo-X-diplo-X), or for $$\widehat{XX}$$ and a marked Y-chromosome $$(\widehat{XX}/Y - \widehat{XX}/O)$$ . The germ-line and genitalia of these females were analysed by direct microscopic observation or by examination of the progeny. Eggs derived from triplo-X germ cells were hardly capable of supporting development, with most of the zygotes dying during embryonic development. The analysis of the germ line was therefore carried out mainly by direct observation of histochemically stained developing oocytes in the ovaries of mosaic females. The total germ cell population of both ovaries of a female was mosaic in 22–29% of the tested animals. From this frequency of mosaicism we estimated the number of functional primordial germ cells to be betwen 3 and 6 cells at the blastoderm stage. At this stage the cell lineages for the left and right ovary are not yet separated. The germ cell population of individual ovarioles was frequently mosaic which shows that the few stem cells in an ovariole are recruited as a group and are not clonal descendants of a single ancestor cell per ovariole. An analysis of the sequential pattern of oocyte-nurse cell cysts in mosaic ovarioles revealed that neighbouring cysts tend to be of the same genotype. This suggests that the stem cells of the adult ovaries preferentially divide in bursts, one of them giving rise to two, three and sometimes even more cystocytes in a row. In addition, the foci for lethality and sterility of the triplo-X condition were determined. Non-mosaic triplo-X females (metafemales) are hardly viable and invariably sterile. Using our mosaics, the focus forlethality could be mapped to a region very near the ventral prothoracic discs. The focus forsterility resides in the genitalia, since flies with triplo-X genitalia never laid any eggs, regardless of the genotype of their ovaries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848668
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  • 7
    Electronic Resource
    Electronic Resource
    Rudimentary mutants ofDrosophila melanogaster (1979)
    Springer
    Development genes and evolution 187 (1979), S. 167-177 
    Details
    ISSN: 1432-041X
    Keywords: Pyrimidine biosynthesis ; rudimentary mutants ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The X-linkedrudimentary (r) mutants ofDrosophila melanogaster are pyrimidine auxotrophs and require exogenous pyrimidines (Nørby, 1970; Falk, 1976). We have established a set ofrudimentary cell lines that are derived from embryos, homozygous for eitherr 1 orr 36. The enzymatic activities of the pyrimidine synthesizing enzymes were measured in the mutant lines. We have further investigated the nutritional requirements of the mutant cells in vitro by using a pyrimidine free culture medium. Ther 1 cell lines were found to express 3–7%dihydroorotase (DHOase) activity as compared to a wildtype cell line. Reducedaspartate transcarbamylase (ATCase) activity was measured in somer 1 cell lines whereas wildtypecarbamylphosphate synthetase (CPSase) activity is expressed in allr 1 cell lines. Ther 36 cell line expresses wildtype activity ofDHOase andCPSase. ATCase activity was found to be reduced to 10% of the wildtype activity. The mutant cell lines do not proliferate in pyrimidine free minimal medium and cell proliferation is obtained by the addition of crude RNA. Proliferation of ther 1 cells is restored by the supplementation of the minimal medium withdihydroorotate whereas proliferation of ther 36 cells is restored by supplementation with eitherdihydroorotate orcarbamylaspartate. The results demonstrate that therudimentary phenotypesr 1 andr 36 are expressed at the cellular level and that the two mutant cell types behave as cellular pyrimidine auxotrophs in vitro.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848269
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  • 8
    Electronic Resource
    Electronic Resource
    The effect of fat body on the differentiation in vitro of wing imaginal discs ofDrosophila melanogaster (1976)
    Springer
    Development genes and evolution 180 (1976), S. 73-77 
    Details
    ISSN: 1432-041X
    Keywords: Ecdysones ; Imaginal discs ; Fat body ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effect of suboptimal levels of α-ecdysone on the differentiation in vitro ofDrosophila melanogaster wing discs was enhanced by the addition of larval fat body to the cultures. However, similar experiments with β-ecdysome showed no enhancement. It is suggested that a partial conversion of α-ecdysone to β-ecdysone by the fat body may well account for these results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848885
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  • 9
    Electronic Resource
    Electronic Resource
    SEM analysis of amphibian mesodermal migration (1977)
    Springer
    Development genes and evolution 181 (1977), S. 31-40 
    Details
    ISSN: 1432-041X
    Keywords: Cell migration ; Mesoderm ; Gastrulation ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary At the end of gastrulation, the lateral mesoderm of amphibian embryos migrates ventrally between the ectoderm and the endoderm. The present study is an examination of the morphology of the leading cells of the mesodermal sheet and of the substratum over which they move (the inner surface of the ectoderm). The cells of the leading edge of the mesoderm are generally round, with very short and narrow flattened projections in the forward direction. These projections do not have a “ruffled” morphology, regardless of whether fixation is carried out before or after the ectoderm and mesoderm are dissected away from the endoderm. The inner surface of the ectoderm is covered with fine (450–500A) filamentous extracellular material and the ectoderm cells sometimes extend cytoplasmic processes (approx. 0.1 μ wide) onto the leading surface of the mesoderm or onto adjacent ectoderm cells. These studies indicate that the morphology of cell migration in amphibians is closer to that seen inFundulus than to that characteristic of chick or mammalian cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00857266
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  • 10
    Electronic Resource
    Electronic Resource
    Developmental potentials of the cells of the male foreleg disc ofDrosophila (1977)
    Springer
    Development genes and evolution 181 (1977), S. 309-320 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila melanogaster ; Male foreleg disc ; Pattern regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. The developmental potentials of the four quadrants of the male foreleg disc ofDrosophila melanogaster were analysed by culturing excised quadrants for 3 days and 10 days in adult hosts prior to metamorphosis. 2. The cultured pieces underwent different types of pattern regulation in a circular direction. The upper medial piece was able to regenerate the missing structures of the disc, thus confirming the findings of earlier reports. The three remaining pieces could undergo pattern duplication in mirror-image symmetry. The lower medial piece revealed in addition a slight capacity for regeneration from the vertical cut surface. 3. The duplicating pieces differed markedly in their frequencies of pattern duplication: duplications occurred with very high frequencies in lower medial pieces, with intermediate frequencies in upper lateral pieces, and with very low frequencies in lower lateral pieces. 4. Both lower lateral and upper lateral pieces underwent a progressive loss of most markers with increasing culture time. 5. Claws were regenerated solely by upper medial pieces. 6. Transdetermined structures, too, were encountered only in upper medial pieces. 7. The results are discussed with respect to the two major current models of pattern regulation in imaginal discs, the “gradient model” and the “clock model”. 8. It is suggested that the differences in the frequencies of pattern duplication reflect the unequal spacing of circular positional values within the three duplicating quadrants. Under this assumption the data indicate a progressive decrease in the density of circular positional values with increasing distance from the upper medial quadrant of the disc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848058
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  • 11
    Electronic Resource
    Electronic Resource
    Growth of embryonic chick tibiae in ovo and in vitro: A scanning electron microscope study (1979)
    Springer
    Calcified tissue international 27 (1979), S. 33-40 
    Details
    ISSN: 1432-0827
    Keywords: Chick embryo ; Bone ; Organ culture ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The study describes the ultrastructure of the mineralized portion of chick tibiae from 10 days in ovo to 2 days post-hatch. At 10 days a single mineralized cylinder surrounds the diaphysis. On its outer surface columnar trabeculae join to form ridges parallel to the long axis of the bone. These ridges are covered by another cylinder and form the haversian canals. At 11 days vascular invasion of the marrow cavity occurs and resorption of the endosteal surface begins. This type of periosteal deposition and endosteal resorption is repeated during and subsequent to embryonic development. The mineralized portion of 10-day chick tibiae cultured for 2 days in modified BGJ medium was compared with 10-, 11-, and 12-day tibiae in ovo. Cultured tibiae were similar in length and calcium content to 11-day tibiae in ovo. The form of mineral deposited in ovo and in culture was the same, namely, aggregates of spherical mineral clusters. Differences in culture included the following: (a) few concentric cylinders were deposited as compared with tibiae in ovo; (b) trabeculae were not arranged in rows and ridges in culture; (c) osteocytic lacunae were restricted to bases of trabeculae rather than uniformly distributed as in ovo; and (d) the endosteal surface of tibiae in culture appeared etched.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441158
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  • 12
    Electronic Resource
    Electronic Resource
    Correlation of freeze-fracture and scanning electron microscopy of epiphyseal chondrocytes (1978)
    Springer
    Calcified tissue international 26 (1978), S. 237-241 
    Details
    ISSN: 1432-0827
    Keywords: Epiphyseal chondrocytes ; Freezefracture ; Scanning electron microscopy ; Cell processes ; Membrane particles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Chondrocytes in epiphyseal cartilage were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) using freeze-fracture techniques. Freeze-fracture replicas showed large numbers of fingerlike, 0.11–0.15 μm diameter, projections from the chondrocyte surface, with numerous 95–180 Å diameter intramembranous particles associated with both the cell membrane surface and these projections. With SEM, these cytoplasmic projections were also obvious, but appeared collapsed into clusters of globular-shaped projections on the surface of the chondrocytes. With freeze-fracture techniques, in which shrinkage artifacts were essentially eliminated, the cytoplasmic projections were often seen in intimate contact with the extracapsular matrix. However, with chondrocytes prepared by both SEM and conventional TEM, there was evidence of shrinkage, the cytoplasmic projections having little contact with the extracapsular matrix. These findings show that the cytoplasmic processes are not artifacts of tissue processing and provide morphological evidence in support of the hypothesis that matrix vesicles are of cellular origin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013264
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  • 13
    Electronic Resource
    Electronic Resource
    Scanning electron microscopical study on the fluorosis of enamel in rats (1978)
    Springer
    Calcified tissue international 25 (1978), S. 75-83 
    Details
    ISSN: 1432-0827
    Keywords: Rat ; Fluorosis ; Enamel ; Scanning electron microscopy ; Low temperature incineration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Sixteen 58-day-old male rats of Wistar strain, with a mean body weight of 179 g, were divided into two equal groups. Each group of eight animals was maintained for 70 days on drinking water, ad lib., containing no fluorine (control group) and 100 ppm of fluorine (experimental group). All specimens examined were obtained from the incisal portions of the incisors. The following types of enamel specimens were prepared for scanning electron microscopy: (1) acid-etched specimens; (2) acid-etched specimens followed by low temperature microincineration; and (3) fractured specimens. The enamel formed during high fluoride exposure showed marked hypocalcification, that is, the crystallite density in the prism core and interprismatic region was lower than that of control animals. The organic substances appeared to increase in these regions. These changes were prominent in the outer and middle enamel layers. Such changes following fluoride administration appear to indicate an inhibition of enamel maturation, that is, an inhibition of the mineral deposition and/or an inhibition of organic matrix withdrawal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010754
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  • 14
    Electronic Resource
    Electronic Resource
    Structure and association of wall fibrils produced by regenerating tobacco protoplasts (1979)
    Springer
    Planta 146 (1979), S. 203-210 
    Details
    ISSN: 1432-2048
    Keywords: Cellulose ; Microfibrils ; Negative staining ; Nicotiana ; Protoplasts ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A study has been made of the wall fibrils produced by tobacco protoplasts, using scanning electron microscopy in conjunction with negative staining. It has been shown that the fibres seen in scanning electron microscopy correspond to aggregates of microfibrils. These aggregates are only visible where they are lifted clear of the protoplast surface. Negative staining of fixed protoplasts shows that the aggregation of microfibrils into the fibres visible in scanning electron microscopy is probably produced by air-drying. Gentle disruption of microfibrils produces both random broken fragments and bundles of short pieces of fibrillar material about 60 nm in length. This material is present in undisrupted young walls, but not in undisrupted older walls. The microfibrils in young walls seem much more fragile and liable to breakage than those in older walls. These results are discussed in terms of the interpretation of scanning electron microscope images and the mechanism of cellulose microfibril formation by higher plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388233
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  • 15
    Electronic Resource
    Electronic Resource
    Localization of α-galactomannan on the surface of Schizosaccharomyces pombe cells by scanning electron microscopy (1977)
    Springer
    Archives of microbiology 112 (1977), S. 123-126 
    Details
    ISSN: 1432-072X
    Keywords: Bandeiraea simplicifolia ; Schizosaccharomyces pombe ; Colloidal gold ; Cytochemistry ; α-Galactomannan-lectin ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Galactomannan was localized by scanning and transmission electron microscopy on the cells and cell walls of Schizosaccharomyces pombe. The markers were prepared from colloidal gold granules labelled with an α-galactopyranosyl-binding lectin isolated from the seeds of Bandeiraea simplicifolia. Part or all of this α-galactomannan was present in the outer layer of the cell wall and was uniformly distributed even on the fission scars.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429323
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  • 16
    Electronic Resource
    Electronic Resource
    Localization of mannan at the surface of yeast protoplasts by scanning electron microscopy (1976)
    Springer
    Archives of microbiology 109 (1976), S. 9-14 
    Details
    ISSN: 1432-072X
    Keywords: Candida utilis ; Saccharomyces cerevisiae ; Colloidal gold ; Cytochemistry ; Mannan ; Plasma membranes ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The β(1→3)glucanase of Basidiomycete QM 806 was used to prepare Saccharomyces cerevisiae and Candida utilis protoplasts. Plasma membranes isolated from S. cerevisiae contained a small amount of mannose and traces of glucose and ribose. Randomly distributed α-mannan was detected by scanning electron microscopy at the surface of prefixed protoplasts using colloidal gold labelled with Concanavalin A as a marker. C. utilis protoplasts were also marked with anti-mannan antibodies. Again the distribution of mannan was random. This experiment indicated also that plasma membrane mannan has the same immunochemical determinants as cell wall mannan. It is hypothesized that mannan is mainly located in the outer layer of plasma membranes.
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    URL: http://dx.doi.org/10.1007/BF00425106
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  • 17
    Electronic Resource
    Electronic Resource
    Mating in Chlamydomonas eugametos (1976)
    Springer
    Archives of microbiology 109 (1976), S. 31-35 
    Details
    ISSN: 1432-072X
    Keywords: Scanning electron microscopy ; Chlamydomonas ; Cell agglutination ; Cell fusion ; Flagella
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A technique has been developed by which mating gametes of Chlamydomonas eugametos can be studied in the Scanning Electron Microscope. A detailed description of the mating process, from the initial flagellar agglutination until the release of free vis-à-vis pairs, is presented. Flagella appear to agglutinate at random points on their surface. This is followed by a rapid increase of the contact area such that they “line-up” tip to tip. Flagella always exhibit a typical position prior to cell fusion. After cell fusion the flagella of a pair separate rapidly while the female have shortened about 33%. In a vis-à-vis pair the plasma bridge has contracted. The observations are interpreted in terms of a specific reorganization of the sexuale aggregate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00425109
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  • 18
    Electronic Resource
    Electronic Resource
    Nutritional control of xanthine dehydrogenase. II. Effects on xanthine dehydrogenase and aldehyde oxidase of culturing wild-type and mutant Drosophila on different levels of molybdenum (1975)
    Springer
    Biochemical genetics 13 (1975), S. 53-64 
    Details
    ISSN: 1573-4927
    Keywords: aldehyde oxidase ; xanthine dehydrogenase ; Drosophila melanogaster ; molybdenum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Two new mutants, deficient in aldehyde oxidase and xanthine dehydrogenase, have been isolated from a wild-type stock of Drosophila melanogaster and have been provisionally termed lxd c and lxd d, respectively, as both mutants appear to be allelic with lxd (low xanthine dehydrogenase). An analysis has been made of the effects of dietary molybdenum on lxd, lxd c, lxdd, lao (low aldehyde oxidase), mal (maroon-like eye color), and pac (Pacific) wild-type flies. On the lower dietary levels of 10 −3 M and 10 −2 M molybdenum, increases in specific activity of both enzymes were observed only in lxd. Furthermore, two- to three-fold increases in specific activity of both enzymes occurred in all strains, except mal, when cultured on 5×10 −2 M molybdenum. The lxd and lxd c strains failed to survive on this high concentration of the ion. Similar concentrations of molybdenum had no effect in vitro. An extra electrophoretic band of xanthine dehydrogenase was observed on polyacrylamide gel from extracts of wild-type flies cultured on certain levels of molybdenum, but its appearance was not always correlated with the increases in specific activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00486006
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  • 19
    Electronic Resource
    Electronic Resource
    The size of poly(A)-containing RNAs in Drosophila melanogaster embryos (1976)
    Springer
    Biochemical genetics 14 (1976), S. 357-371 
    Details
    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; poly(A)-containing RNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The size range of poly(A)-containing RNA from Drosophila melanogaster embryos has been estimated by hybridization with 3H-labeled poly(U) and subsequent fractionation on sucrose gradients. The median size of nuclear poly(A)-containing RNA is about 30 S (6000 nucleotides), and the median size of cytoplasmic poly(A)-containing RNA is about 17 S (1800 nucleotides). The relationship of these sizes to messenger RNA needed to code for protein and to the length of DNA contained in a chromomere is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00484774
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  • 20
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    Electronic Resource
    Partial purification and properties of guanosine triphosphate cyclohydrolase from Drosophila melanogaster (1976)
    Springer
    Biochemical genetics 14 (1976), S. 259-270 
    Details
    ISSN: 1573-4927
    Keywords: GTP cyclohydrolase ; Drosophila melanogaster ; pteridines ; dihydroneopterin triphosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The first enzyme (named GTP cyclohydrolase) in the pathway for the biosynthesis of pteridines has been partially purified from extracts of late pupae and young adults of Drosophila melanogaster. This enzyme catalyzes the hydrolytic removal from GTP of carbon 8 as formate and the synthesis of 2-amino-4-hydroxy-6-(d-erythro-1′,2′,3′-trihydroxypropyl)-7,8-dihydropteridine triphosphate (dihydroneopterin triphosphate). Some of the properties of the enzyme are as follows: it functions optimally at pH 7.8 and at 42 C; activity is unaffected by KCl and NaCl, but divalent cations (Mg2+, Mn2+, Zn2+, and Ca2+) are inhibitory; the K m for GTP is 22 μm; and the molecular weight is estimated at 345,000 from gel filtration experiments. Of a number of nucleotides tested, only GDP and dGTP were used to any extent as substrate in place of GTP, and these respective compounds were used only 1.8% and 1.5% as well as GTP.
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    The suppressor of forked mutation in Drosophila melanogaster: Interactions with the lozenge gene (1976)
    Springer
    Biochemical genetics 14 (1976), S. 611-617 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; phenol oxidases ; spectrophotometry ; electrophoresis ; suppression ; ribosomal proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract An interaction between the lozenge gene and the suppressor of forked gene of Drosophila melanogaster has been investigated both spectrophotometrically and electrophoretically. The nature of this interaction is such that certain lozenge alleles appear to be phenotypically suppressed while others are enhanced or unaffected, and the results reported demonstrate that the effect can clearly be observed at the biochemical level. Earlier observations have suggested that the suppressor of forked gene codes for a ribosomal protein, and this hypothesis is discussed.
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    Selection against homozygotes in the ADH polymorphic system of Drosophila melanogaster associated with the lethal factor l(2) Stm (1977)
    Springer
    Biochemical genetics 15 (1977), S. 93-100 
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    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase (ADH) ; genetic polymorphism ; selection ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In the natural populations +Tüb, +Prov, and +Rov, similar Adh F allele frequencies occur (q F=0.11, 0.18, and 0.08, respectively). However, there is a discrepancy in that the Adh F allele in +Tüb is closely linked to the lethal factor 1(2)Stm, which reduces relative fitness of the F phenotype to zero. In spite of this, polymorphism is maintained also in +Tüb, because the heterozygotes are superior to the homozygous S type (relative fitness=0.88). Under laboratory culture conditions, in +Tüb the relative fitness of the S genotype further decreases to 0.6. After outcrossing the lethal factor, relative fitnesses for S, FS, and F become 0.6, 1, and 0.48, respectively, implying that fitness for S remains the same. Relative values for S, FS, and F in +Prov, not affected by the lethal factor, are calculated by the maximum average fitness method to be 1, 1.2, and 0.2 under the assumption that heterozygous FS are similarly superior to S as in the natural +Tüb population and all allele frequencies found are stable equilibrium values.
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    Origin of α-glycerophosphate dehydrogenase isozymes in Drosophila melanogaster and their functional relationship in the α-glycerophosphate cycle (1977)
    Springer
    Biochemical genetics 15 (1977), S. 235-251 
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    ISSN: 1573-4927
    Keywords: l-glycerol-3-phosphate dehydrogenase (α-GPDH) ; isozymes ; development ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The basis for the differentiation of l-glycerol-3-phosphate dehydrogenase (α-GPDH) into larval and adult isozymes in Drosophila melanogaster was investigated by the correlation of a lack of appearance of each isozyme during development within Drosophila bearing α-GPDH “null” alleles and by the study of a putative conversion factor. Conversion studies indicate the presence of a heat-labile RNase-resistant conversion factor present in crude larval extracts with the ability to convert GPDH-1 to GPDH-2 and GPDH-3 but not vice versa. In addition, “null” mutations at the Gpdh locus obliterate all isozymatic species of α-GPDH in all developmental stages. These observations suggest that all α-GPDH isozymes are the product of a single structural gene and that the multiple forms of this enzyme arise during successive developmental stages through an epigenetic modification of the primary Gpdh + polypeptide. Finally, observations are reported which bear on the functional divergence of the α-glycerophosphate cycle in the adult and larval stage of development.
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    Isolation and genetic characterization of alcohol dehydrogenase thermostability variants occurring in natural populations of Drosophila melanogaster (1977)
    Springer
    Biochemical genetics 15 (1977), S. 971-988 
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    ISSN: 1573-4927
    Keywords: allozymes ; thermostability ; alcohol dehydrogenase ; Drosophila melanogaster ; natural populations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Drosophila melanogaster collected from natural populations were examined fo thermostability variants within electrophoretic mobility classes of two enzymes. In alcohol dehydrogenase, two discrete forms of the “slow” allozyme and three discrete forms of the “fast” allozyme were revealed by postelectrophoretic treatments ranging from 15 sec at 40 C to 40 sec at 43 C. All variants have been mapped to within 0.7 unit of the Adh locus. Results of a geographic survey indicate that two alleles giving rise to fast-moderate and slow-moderate allozymes are common everywhere; other variants have a collective frequency ranging from 0% to 7%. In a test of the possibility that the rare Adh alleles could be generated by intragenic recombination between the two common alleles, electrophoresis and heat treatment of progeny recombinant for flanking markers of Adh revealed no new allozymes. Among 27 stocks containing slow α-glycerophosphate dehydrogenase allozymes and 109 fast stocks, heat treatments revealed no additional variation.
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    Control of drosopterin synthesis in Drosophila melanogaster: Mutants showing an altered pattern of GTP cyclohydrolase activity during development (1978)
    Springer
    Biochemical genetics 16 (1978), S. 13-26 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; GTP cyclohydrolase ; development ; pteridine biosynthesis ; mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The reaction catalyzed by GTP cyclohydrolase is the first unique step of pteridine biosynthesis in Drosophila melanogaster and is therefore likely to be an important control point. GTP cyclohydrolase activity varies during development, showing two distinct peaks of activity—one at pupariation and a much larger peak at emergence. Most of the early pupal enzyme is located in the body region, whereas in late pupal and early adult life most of the activity is found in the head. Mixing experiments indicate that developmental changes in activity are not due to changes in the level of a direct effector of GTP cyclohydrolase. The mutants raspberry and prune show an increased GTP cyclohydrolase activity at pupariation relative to wild type, but a decreased enzyme activity at emergence. The changes in GTP cyclohydrolase activity are reflected in changes in pteridine levels in these mutants. Several lines of evidence suggest that neither locus is the structural gene for GTP cyclohydrolase. The raspberry and prune gene products may play a specific role in regulating GTP cyclohydrolase activity during development.
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    A genetic and developmental analysis of an acid deoxyribonuclease in Drosophila melanogaster (1978)
    Springer
    Biochemical genetics 16 (1978), S. 1113-1134 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; isozymes ; position effect ; segmental aneuploidy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A deoxyribonuclease, called DNase-1, that is active at acid pH in the presence of EDTA has been studied in Drosophila melanogaster. The locus for the enzyme maps genetically to 61.8 on the right arm of the third chromosome. Cytogenetically, DNase-1 has been localized to within five to ten bands between 90C-2 and 90E. This analysis utilizes both electrophoretic variants and the Y-autosome translocations of Lindsley et al. (1972). DNase-1 is present in all stages of the life cycle, and the paternal genome actively contributes DNase-1 to the embryo between 0 and 1 hr after fertilization.
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    Variation in amount of enzyme protein in natural populations (1978)
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    Biochemical genetics 16 (1978), S. 159-170 
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    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase ; allozyme properties and amounts ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Among strains of Drosophila melanogaster each derived from a single fertilized female taken from natural populations, there is variation in both alcohol dehydrogenase (ADH) activity and the amount of ADH protein. The correlation between ADH activity and number of molecules over all strains examined is 0.87 or 0.96 in late third instar larvae depending on whether the substrate is 2-propanol or ethanol. With respect to the two common electrophoretic allozymic forms, F and S, segregating in these populations, the FF strains on the whole have higher ADH activities and numbers of ADH molecules than the SS strains. Over all strains examined, enzyme extracts from FF strains have a mean catalytic efficiency per enzyme molecule higher than that of enzyme extracts from SS strains when ethanol is the substrate, and much higher when 2-propanol is the substrate. One FF strain had an ADH activity/ADH protein ratio characteristic of SS strains.
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    Alcohol metabolism in Drosophila melanogaster: Uselessness of the most active aldehyde oxidase produced by the Aldox locus (1978)
    Springer
    Biochemical genetics 16 (1978), S. 203-211 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; alcohol tolerance ; alcohol utilization ; alcohol dehydrogenase ; aldehyde oxidase ; allozymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Alcohol dehydrogenase is necessary for ethanol detoxification and metabolic utilization. It has been generally assumed that aldehyde oxidase (AO) produced by the Aldox locus (3–56.7) is necessary for a further transformation of acetaldehyde into acetate. We find that various mutant strains (ma-l or Aldox n) which do not produce an active enzyme show about the same tolerance to alcohol as do wild strains. This physiological paradox is probably to be explained by the discovery of another locus (not localized) which produced a small amount of AO in all tested strains. The adaptive significance of the genetically polymorphic Aldox locus is probably to be looked for in physiological pathways other than ethanol metabolism.
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    A simple approach for discovering common nonelectrophoretic enzyme variability: A heat denaturation study in Drosophila melanogaster (1978)
    Springer
    Biochemical genetics 16 (1978), S. 299-305 
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    ISSN: 1573-4927
    Keywords: nonelectrophoretic structural variability ; Drosophila melanogaster ; phosphoglucomutase ; genetic polymorphism ; heat denaturation study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A simple procedure is described to detect genetic heterogeneity within electrophoretic classes at a locus in Drosophila, based on electrophoresis and heat denaturation studies. Temperature-resistant (tr) and temperature-sensitive (ts) isoelectrophoretic alleles at the phosphoglucomutase locus (Pgm) are present at polymorphic frequencies in natural and in laboratory populations of Drosophila melanogaster.
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    Developmental changes of sepiapterin synthase activity associated with a variegated purple gene in Drosophila melanogaster (1979)
    Springer
    Biochemical genetics 17 (1979), S. 197-206 
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    ISSN: 1573-4927
    Keywords: sepiapterin synthase ; variegation ; purple ; Drosophila melanogaster ; pteridine eye pigments ; drosopterin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A variegated position effect on the autonomous gene, purple, has been studied enzymologically in Drosophila melanogaster. Sepiapterin synthase, the enzyme system associated with pr +, was examined for activity in different developmental stages of the fly. The results indicate that T(Y:2) pr c5, cn/prc4 cn flies (flies in which pr + has been translocated and which exhibit variegation) have a reduced amount of enzyme activity as compared with both Oregon-R and pr 1 flies. This reduction in activity was not found in larval stages, which suggests that the inactivation process probably occurs in late larval or early pupal stages. The phenotype of the variegated adult has white eyes with red-colored spots and patches where drosopterins occur. The phenotype of the fly carrying the translocation is modified by the presence of additional Y chromosomes. This extends the observation from other systems that extra heterochromatin acts to suppress the variegated position effect. The advantages of studying the variegation by measuring enzyme activity, as well as the phenotypic expression, are several; for example, the developmental time at which variegation occurs may be estimated even though drosopterin synthesis is not occurring.
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    Polymorphism at the G6pd and 6Pgd loci in Drosophila melanogaster. III. Developmental and biochemical aspects (1979)
    Springer
    Biochemical genetics 17 (1979), S. 1131-1144 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; enzyme polymorphism ; G6PD ; 6PGD ; enzyme activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The electrophoretic variants of G6PD and 6PGD isolated from the Bogota Drosophila melanogaster population were characterized developmentally and biochemically. Changes in in vitro enzyme activity during development were comparable to those found for other dehydrogenases: an increase in the larval and adult stage and a decrease in the pupal stage. During the whole life cycle the “S” enzyme of both loci showed a higher activity than the “F” enzyme. MgCl2 had a stimulating effect on the activity of both enzymes whereas their heat stability was decreased. The allozymes of 6PGD had different Vmax's but were comparable with respect to Km values, pH optimum, and stability at 45 C. the allozymes of G6PD showed different Vmax's and differed in stability at 35 C, but had similar Km values and pH optima. As the difference in stability was probably due to differences in molecular structure of the allozymes, the differences in activity found at high pH and high MgCl2 concentration were most probably due to this difference in stability.
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    Transport defects as the physiological basis for eye color mutants of Drosophila melanogaster (1975)
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    Biochemical genetics 13 (1975), S. 603-613 
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    ISSN: 1573-4927
    Keywords: transport mutants ; eye color mutants ; kynurenine ; Drosophila melanogaster ; Malpighian tubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Kynurenine-H 3 transport and conversion to 3-hydroxykynurenine were studied in organ culture using the Malpighian tubules and developing eyes from wild type and the eye color mutants w, st, 1td, ca, and cn of Drosophila melanogaster. Malpighian tubules from wild type have the ability to concentrate kynurenine and convert it to 3-hydroxykynurenine. The tubules from w, st, 1td, and ca are deficient in the ability to transport kynurenine, as are the eyes of the mutants w, st, and 1td. This defect in kynurenine transport provides a physiological explanation for the phenotypic properties of the mutants. The relationship of these measurements to previous observations on these eye color mutants is discussed and the transport defect hypothesis is consistently supported. We have concluded that several of the eye color mutants in Drosophila are transport mutants.
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    Correlation of guanosine triphosphate cyclohydrolase activity and the synthesis of pterins in Drosophila melanogaster (1976)
    Springer
    Biochemical genetics 14 (1976), S. 271-280 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; GTP cyclohydrolase ; pteridine biosynthesis ; development ; mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The enzyme guanosine triphosphate cyclohydrolase (GTP cyclohydrolase), which in bacteria is known to be the first enzyme in the biosynthetic pathway for the synthesis of pteridines, has been discovered in extracts of Drosophila melanogaster. Most of the enzyme (80%) is located in the head of the adult fly. An analysis of enzyme activity during development in Drosophila has revealed the presence of a relatively small peak of activity at pupariation and a much larger peak that appears at about the time of eclosion. Enzyme activity declines rapidly as the fly ages. Analyses for the production of the typical pteridine pigments of Drosophila have indicated that the small peak of GTP cyclohydrolase activity evident at pupariation coincides with the appearance of isoxanthopterin, sepiapterin, and pterin, and the larger peak at eclosion roughly corresponds to the accumulation of drosopterin as well as to the appearance in larger amounts of pterin and sepiapterin. These observations strongly suggest that in Drosophila, like bacteria, GTP cyclohydrolase is involved in the biosynthesis of pteridines. Analyses of a variety of zeste mutants of Drosophila melanogaster have shown that these mutants all contain GTP cyclohydrolase equal approximately to the amount found in the wild-type fly. These observations do not support the suggestions made by Rasmusson et al. (1973) that zeste is the structural locus for GTP cyclohydrolase.
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    Genetics and physiological expression of β-hydroxy acid dehydrogenase in Drosophila (1978)
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    Biochemical genetics 16 (1978), S. 333-342 
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    ISSN: 1573-4927
    Keywords: β-hydroxy acid dehydrogenase ; chromosome ; dosage compensation ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A mutant Had nl was induced in Drosophila melanogaster and found to be deficient in β-hydroxy acid dehydrogenase. This mutation was utilized to study the genetics and physiological expression of Had +. Had+ was mapped to the X chromosome at 54.4 and seems to be the structural gene for the enzyme. Enzyme activity in male and female flies indicates that the gene shows both dosage compensation independent from dose effect and differential activity during ontogeny. Electrophoretic mobility data indicate that the enzyme is a dimer which forms by random association of subunits. The fact that the mutant shows no detrimental effect implies that the enzyme is dispensable, at least under laboratory conditions. The biological and technical implications of this gene-enzyme system are discussed.
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    Dietary rescue of a lethal “null” activity allele of 6-phosphogluconate dehydrogenase in Drosophila melanogaster (1978)
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    Biochemical genetics 16 (1978), S. 469-475 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; 6-phosphogluconate dehydrogenase ; Pgd n lethal alleles ; rescue by dietary supplements ; hexose monophosphate shunt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The genetic rescue of Pgd n lethal alleles, accomplished by combining them with mutations lacking glucose-6-phosphate dehydrogenase activity, has led to the hypothesis that Pgd n lethality may be due to the accumulation of 6-phosphogluconate. In this article we report the rescue of Pgd n /Y males by dietary supplements (fructose and linolenate) designed to minimize 6-phosphogluconate production.
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    Biochemical properties of esterase 6 in Drosophila melanogaster (1979)
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    Biochemical genetics 17 (1979), S. 1-22 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; esterase 6 ; allozymes ; biochemical properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Biochemical properties of esterase 6 in Drosophila melanogaster were investigated using partially purified preparations from three genotypes, 1/1, 1/2, and 2/2. The molecular weight of the enzyme is estimated to be about 90,000, and treatment with sodium dodecylsulfate cleaves the enzyme into four units with a molecular weight of about 22,000. The activity toward 28 naturally occurring esters was assayed and shown to vary considerably with substrate, the 1/1 preparation having in general higher activity than 1/2 and 2/2, which were very similar. Heat sensitivity, the effect of metal ions, and the effects of the presence or absence of an end product were also studied. The differences demonstrated between allozymes would allow considerable scope, under appropriate conditions, for differential selection to operate between genotypes.
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    Properties of the two common electrophoretic variants of phosphoglucomutase in Drosophila melanogaster (1979)
    Springer
    Biochemical genetics 17 (1979), S. 825-836 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; phosphoglucomutase ; polymorphism ; enzyme kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Phosphoglucomutase (PGM) of adult stage in Drosophila melanogaster has been characterized by gel filtration, ion-exchange chromatography, and isoelectric focusing. The two common electrophoretic variants, PGMA and PGMB, differ with respect to their kinetic and stability parameters. PGMA is more thermostable than PGMB but shows the same pH optimum, equal dependence on Mg2+, and identical molecular weight. There is no significant kinetic difference between the two allozymes at the optimum pH value, but at pH 6.0 the K m value for glucose-1,6-diphosphate of PGMB is significantly higher than that of PGMA. This difference might explain the observed selective advantage of the Pgm A allele in population studies.
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    Biological role of alcohol dehydrogenase in the tolerance of Drosophila melanogaster to aliphatic alcohols: Utilization of an ADH-null mutant (1976)
    Springer
    Biochemical genetics 14 (1976), S. 989-997 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; alcohol dehydrogenase ; enzyme biological activity ; toxicity of alcohols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The toxicity of the first eight primary alcohols and of four secondary alcohols was compared in a wild-type strain (having active ADH) and an ADH-negative mutant. Differences between lc 50 measured in the two strains allowed an evaluation of the biological activity of the enzyme. In vitro, ADH is mainly active on secondary alcohols, while in vivo its main role is the detoxification and metabolism of ethanol. These observations suggest that originally ADH was involved in unknown metabolic pathways and that its utilization in ethanol metabolism could be a recent event.
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    Preparation of specific antisera to Drosophila acid phosphatase without rigorous protein purification (1976)
    Springer
    Biochemical genetics 14 (1976), S. 237-243 
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    ISSN: 1573-4927
    Keywords: null alleles ; antibody purification ; Drosophila melanogaster ; immunological methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Extracts from an acid phosphatase CRM− null mutant of Drosophila melanogaster were used to eliminate contaminating antibodies in a nonspecific preparation of anti-acid phosphatase serum. This method of producing specific antisera makes unnecessary the rigorous purification of an antigen prior to immunization attempts in those cases where CRM− null mutants of the antigen are available. Antisera so prepared could be used for a wide variety of purposes.
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    Association and the Adh locus with a lethal factor (l(2) Stm) in Drosophila melanogaster (1976)
    Springer
    Biochemical genetics 14 (1976), S. 299-308 
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    ISSN: 1573-4927
    Keywords: allozymes ; alcohol dehydrogenase ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Keeping Drosophila cultures at 28 C results in elimination of all minor multiple ADH bands, thought to be due to conformational change. Thus in diploid and triploid adults heterozygous for the Adh F and Adh Salleles, relative staining intensities are found for the three bands which were in conformity with the assumption that both alleles are equally expressed. Among all polymorphic strains derived from natural Central European and Mediterranean populations, the strain +Tüb is unique in that its Adh Fallele is closely linked to a new recessive lethal factor, named 1(2)Stm. All Adh F 1/AdhF 1 pupae are unable to emerge, and die. The lethal effect is obvious 50 hr earlier by retarded eye, bristle, and body wall pigmentation. Although all pupae of the phenotype F die, Adh F allele frequency scarcely seems to be lowered in this natural population.
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    Further evidence of thermostability variation within electrophoretic mobility classes of enzymes (1976)
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    Biochemical genetics 14 (1976), S. 383-387 
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    ISSN: 1573-4927
    Keywords: allozymes ; thermostability ; alcohol dehydrogenase ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Two Drosophila melanogaster strains, each heterozygous for “fast” and “slow” alleles at the Adh locus, and each having balanced second chromosomes, were found to differ in the apparent thermostability of the slow allozyme. The two strains were crossed, and F1heterozygotes were separated on the basis of the origin of the slow allele. After electrophoresis, the cellulose acetate strips were treated 1 1/2 min at 35 C. The putatively more sensitive allozyme showed a strikingly greater response to heat. These findings further support the conclusion that electrophoretically cryptic allelic differences exist which are expressed in thermostability differences. Further application of this approach has revealed one similar sensitive slow allozyme and three cases of a relatively resistant fast ADH allozyme in wild-caught flies.
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    Demonstration of 6-phosphogluconolactonase activity in Drosophila melanogaster using a null allele of 6-phosphogluconate dehydrogenase (1978)
    Springer
    Biochemical genetics 16 (1978), S. 1023-1029 
    Details
    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; 6-phosphogluconolactonase ; hexose monophosphate shunt ; Pgd n Zw n mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Using a double mutant strain, Pgd n Zw n , we have developed an assay for 6-phosphogluconolactonase activity and have demonstrated its occurrence in adult Drosophila melanogaster.
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    Enumeration of Drosophila form II DNA-dependent RNA polymerase initiation sites on Drosophila DNA (1979)
    Springer
    Biochemical genetics 17 (1979), S. 97-104 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; form II RNA polymerase initiation sites ; chromomeres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The in vitro incorporation of γ-32P-labeled nucleoside triphosphates into RNA by Drosophila melanogaster form II RNA polymerase from template sites which afford protection from the initiation inhibitor, polyriboinosinic acid (poly [I]), is used as a method for enumerating a specific class of transcription initiation sites on D. melanogaster DNA. Such sites number about 4000 per haploid genome for D. melanogaster. This value is in good agreement with the number of functional genetic units in the D. melanogaster genome as determined by classical cytogenetics.
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    Purine transport by Malpighian tubules of pteridine-deficient eye color mutants of Drosophila melanogaster (1979)
    Springer
    Biochemical genetics 17 (1979), S. 565-573 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; Malpighian tubules ; purine transport ; eye color mutants ; riboflavin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Uptakes of guanine into Malpighian tubules of wild-type Drosophila and the eye color mutants white (w), brown (bw), and pink-peach (p p) have been compared. Tubules for each of these mutants are unable to concentrate guanine intracellularly. The transport of xanthine and riboflavin is also deficient in w tubules. The transport of guanosine, adenine, hypoxanthine, and guanosine monophosphate is similar in wild-type and white Malpighian tubules. These data and other information about these mutants make it likely that these pteridine-deficient eye color mutants do not produce pigments because of the inability to transport a pteridine precursor. This view supports the hypothesis that mutants which lack both pteridine and ommochromes do so because precursors to both classes of pigments share a common transport system.
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    Variants of α-glycerophosphate dehydrogenase in diploids and triploids of Drosophila melanogaster (1975)
    Springer
    Biochemical genetics 13 (1975), S. 263-271 
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    ISSN: 1573-4927
    Keywords: allozymes ; α-glycerophosphate dehydrogenase ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract On the basis of band staining intensities in electrophoretic runs of single flies homozygous and heterozygous for two alleles at the autosomal locus for GPDH, F allele activity is believed to be 8% lower than S allele activity. Indeed, the intensity distribution in the patterns of FSS and FFS triploid females shows that both are not equally expressed. On a per fly or live weight basis, females with two and three doses of the Gpdh gene show bands with equal staining intensity, thus exhibiting a dosage effect when GPDH activity is estimated on a per cell basis.
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    Variation between electrophoretically identical alleles at the alcohol dehydrogenase locus in Drosophila melanogaster (1975)
    Springer
    Biochemical genetics 13 (1975), S. 721-731 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; enzyme variation ; alcohol dehydrogenase ; electrophoretically identical alleles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A new variant of alcohol dehydrogenase (ADH 71k) was found in a laboratory stock of Drosophila melanogaster. ADH in this stock had the same electrophoretic mobility as the F variant both on acrylamide and on agar. Activity levels were similar to the levels in F flies at temperatures between 15 and 25 C. But while ADH F enzyme is inactivated rapidly at 40 C, ADH 71k is still active. Also, ADH S is not inactivated at this temperature, but has a far lower activity per fly than ADH 71k. Genetic analysis showed that the new variant is an allele of the Adh locus.
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    Isozyme variability in species of the genus Drosophila. VIII. The alcohol dehydrogenase polymorphism in north carolina populations of D. melanogaster (1976)
    Springer
    Biochemical genetics 14 (1976), S. 47-58 
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    ISSN: 1573-4927
    Keywords: electrophoresis ; alcohol dehydrogenase ; Drosophila melanogaster ; isozymes ; genetic variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Adult Drosophila melanogaster flies collected from populations broadly dispersed over ecological and geographic strata of North Carolina, and over a period of 4 years, were analyzed for alcohol dehydrogenase phenotypes by gel electrophoresis. Gene frequencies in spring-summer-fall field collections were remarkably stable over all strata. Two winter collections exhibited contrasting gene frequency changes. In one case the results are interpreted in terms of long-distance migration from Florida, while the other is explicable by assignment of a causal role to environmental factors which accompany the winter season.
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    Heat stability studies at the α-glycerophosphate dehydrogenase locus in populations of Drosophila melanogaster (1978)
    Springer
    Biochemical genetics 16 (1978), S. 769-775 
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    ISSN: 1573-4927
    Keywords: hidden variation ; α-GPDH ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The level of hidden variation in populations of Drosophila melanogaster at the Gpdh + locus was determined by thermal stability studies of the protein. The results indicate a lack of variation using these methods both in and between the two common electrophoretic variants. It is suggested that α-GPDH is conserved in primary structure, which may be related to its critical role in flight muscle metabolism.
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    Mutagenesis at the cinnabar locus in Drosophila melanogaster (1978)
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    Biochemical genetics 16 (1978), S. 855-865 
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    ISSN: 1573-4927
    Keywords: kynurenine hydroxylase ; cinnabar locus ; EMS mutagenesis ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A study was undertaken to isolate mutations affecting the temporal appearance of kynurenine hydroxylase in Drosophila melanogaster. Such mutations, lacking or having reduced enzyme activity at the larval or pupal stage only, could represent changes in regulatory functions. Mutagenesis was carried out using EMS. Potential mutations were isolated from mass F1 cultures. The screening of large numbers of individuals was made possible by the use of the mutant red, which allowed visual classification for the presence or absence of the enzyme at both stages. From a series of six mutagenesis experiments 111,561 chromosomes were tested, and 122 phenotypically mutant F1 individuals were found. From these, 38 inheritable mutations were isolated which, by phenotypic observation, lacked or had reduced enzyme activity at the larval and pupal stages. Assay of enzyme activity levels in several of the mutants confirmed the phenotypic data. All of the 27 mutations that could be tested further are recessive and behave as cinnabar alleles. Complementation tests were performed between these 27 mutant stocks, and no complementation in the production of eye color has been seen between the mutants examined. When extended collection periods were used, a significantly higher percentage of inheritable mutations was isolated from the first 3 days of the screen. Over 80% of the F1 phenotypic mutants could be classified as mosaics, which indicates that cinnabar can be autonomous under certain conditions. The failure to isolate mutations in possible regulatory function is discussed.
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    Isolation and biochemical analysis of a temperature-sensitive scarlet eye color mutant of Drosophila melanogaster (1979)
    Springer
    Biochemical genetics 17 (1979), S. 149-158 
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    ISSN: 1573-4927
    Keywords: xanthommatin synthesis ; scarlet mutants ; Drosophila melanogaster ; temperature-sensitive mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Six new EMS-induced scarlet mutants were selected. Four of these were partially pigmented, with xanthommatin levels ranging from 12% to 45% of normal. In one (st 754ts), pigment production was temperature sensitive; the level of xanthommatin changed from less than 10% of normal at 29 C to more than 70% at 18 C. In all of the new mutants tested, the level of early pupal 3-hydroxykynurenine was as low as low as that in st 1. Thus reduced larval accumulation of this metabolite also appears to be a characteristic feature of scarlet mutants. Temperature-pulse and temperature-shift experiments were carried out with st 754ts to determine the temperature-sensitive period for the scarlet gene during development. The major sensitive period commenced prior to the onset of pigmentation and was over before adult emergence. Thus the initiation of xanthommatin synthesis is not brought about by the activation of the scarlet gene. In similar experiments carried out with a temperature-sensitive white mutant (w bl), a similar temperature-sensitive period was obtained.
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    Partial purification and some properties of biopterin synthase and dihydropterin oxidase from Drosophila melanogaster (1979)
    Springer
    Biochemical genetics 17 (1979), S. 351-369 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; biopterin synthesis ; oxidation of dihydropterins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract An enzyme which has been named “biopterin synthase” has been discovered in Drosophila melanogaster. This enzyme, which has been purified 200-fold from extracts of Drosophila, catalyzes the conversion of sepiapterin to dihydrobiopterin, or oxidized sepiapterin to biopterin. The K m values for the two substrates are 63 µm for sepiapterin and 10 µm for oxidized sepiapterin. NADPH is required in this enzymatic reaction. An analysis of enzyme activity during development in Drosophila indicates a correlation between enzyme activity and biopterin content at various development stages. Another enzyme, called “dihydropterin oxidase,” was also discovered and partially purified. This enzyme catalyzes the oxidation of dihydropterin compounds to the corresponding pterin compounds. For example, sepiapterin (a dihydropterin) is oxidized to oxidized sepiapterin in the presence of this enzyme. The only dihydropterin that has been tested that is not a substrate for this enzyme is dihydroneopterin triphosphate, the compound thought to be a precursor for all naturally occurring pterins and dihydropterins. Since the action of dihydropterin oxidase is reduced significantly when the concentration of oxygen is very low, it is likely that this enzyme uses molecular oxygen as the oxidizing agent during the oxidation of dihydropterins. Neither NAD+ or NADP+ is required. In the presence of the two enzymes dihydropterin oxidase and biopterin synthase, sepiapterin is converted to biopterin. However, in the presence of biopterin synthase alone, sepiapterin is converted to dihydrobiopterin.
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    Structural and functional analysis of the scute locus in Drosophila melanogaster (1979)
    Springer
    Theoretical and applied genetics 55 (1979), S. 231-238 
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    ISSN: 1432-2242
    Keywords: Drosophila melanogaster ; Scute locus ; Maps ; Operon-like model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The functional expression of 12 scute alleles in homozygotes and compounds of Drosophila melanogaster at 14°, 22°, 30°C is analysed. Based on the data obtained, linear maps for bristles and mutations are built. The basic features of the maps, clustering and polarity, are invariable with respect to temperature, scute gene dosage and cross direction. In addition local dominance of the norm over bristle reduction was produced by the scute mutation; different types of complementation reactions were established for each bristle. The gene scute is treated as an operon-like system, composed of 3–4 cistrons with each controlling the formation of bristles on a particular region of the fly's body. This model argues well with the structure of maps constructed and implies a post-translational level of initial events of bristle-formation process.
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    The surface of the pecten oculi in the pigeon (1975)
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    Cell & tissue research 157 (1975), S. 457-465 
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    ISSN: 1432-0878
    Keywords: Pecten oculi ; Pigeon ; Surface ; Function ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A scanning electron microscopic study of the pecten reveals the rib-like character of the pectinal folds, the nature of their connections with the base and bridge of the pecten as well as the presence of interconnections between the bundles of superficial collagenous fibres. It has been suggested that the pecten may have a mechanical significance, namely protection of the retina from the excessive movements of the vitreous humour. The relationship between the superficial membrane of the folds which is continuous, the intercellular spaces and the process of diffussion has also been discussed.
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    Scanning electron microscopic studies on the development of the chick retina (1976)
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    Cell & tissue research 170 (1976), S. 145-159 
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    ISSN: 1432-0878
    Keywords: Neurogenesis ; Retina ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Fixed retinae of chick embryos and chicks of the first week after hatching were fractured and examined with the scanning electron microscope. The matrix cells of the retina proliferate up to the beginning of the second week. The migrating cells are oriented in cell cords. This columnar organization prevails up to the development of the plexiform layers formed as a consequence of the outgrowth of the dendritic and axonal cell processes. Special attention was paid to the differentiation of the ganglion, bipolar and receptor cells, and the radial fibers (Müller cells). Two main morphological patterns are significant for the organization of the retina during neurogenesis: a) the cell to cell contacts of migrating cells and b) the spatial arrangement of Müller cells which could provide guidelines for migration of neuronal elements.
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    Osteoblasts and collagen orientation (1975)
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    Cell & tissue research 159 (1975), S. 73-80 
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    ISSN: 1432-0878
    Keywords: Osteoblasts ; Collagen orientation ; Parietal bone ; Rat, Rhesus monkey ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Bone was removed from the calvaria of anaesthetized 70 g rats or freshly killed young monkeys and the fibrous periosteum dissected off the inner, formative surface under 0.15 M cacodylate buffer. The bone and undisturbed osteoblasts were fixed in 3% glutaraldehyde in the same buffer for 24 to 48 hours, critical point dried and coated with evaporated carbon and gold for scanning electron microscopy (SEM). Fields of osteoblasts were photographed and chosen cells dissected off the osteoid using a tungsten needle. The control of the dissection was made possible by the use of a system of real-time stereo TV-speed SEM. The fields were rephotographed and the orientations of the osteoblasts were compared with that of the underlying collagen fibres. 62% of all osteoblasts lay with their long axes within 15° of the collagen fibre orientation below and 80% within 30°. Montages of large areas of osteoblasts were also made, and then compared with ones of the same area after the cells had been stripped off on adhesive tape. In general, the orientation of the collagen tended to be the same as the cell that formed it. Collagen fibres below cells at the periphery of a domain sometimes had the orientation of the cells in the adjacent patch. It is not possible to determine whether the cells controlled the orientation of the collagen, or vice versa, from this experiment, but other SEM evidence suggests that the collagen orientation in hard tissue matrices depends on the freedom of cells to move with respect to the matrix surface.
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    Scanning electron microscopic studies of the rat incisor odontoblastema (1975)
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    Cell & tissue research 159 (1975), S. 233-243 
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    ISSN: 1432-0878
    Keywords: Odontoblasts ; Predentine ; Dentine ; Calcification ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A scanning electron microscopic technique was used to investigate the surface structure of dentinogenically active odontoblasts. Thin pieces of rat incisors were fixed, rapidly frozen, freezedried at -70° C and fractured to expose new surfaces prior to examination in the SEM. Differences in the appearance of odontoblastic cell surfaces were seen, with the most extensive ridge formations at the distal part of the sides of the odontoblasts. The predentine area displayed a spongy structure which contrasted to the compact appearance of dentine. Results are discussed in relation to previous studies at the light microscopic and transmission electron microscopic levels.
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    Electron microscopic studies of the lung of the frog (1975)
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    Cell & tissue research 160 (1975), S. 399-410 
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    ISSN: 1432-0878
    Keywords: Lung ; Frog ; Alveolar epithelium ; Mucus layer ; Scanning electron microscopy ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scanning and transmission electron microscopy were used to study the inner architecture of the frog lung. In some specimens the alveolar surface mucus layer was removed to permit the examination of underlying features. The inner surface of the frog's lung is covered by a layer of microvilli belonging to only one type of epithelial cells. The boundaries of these epithelial cells are demarcated by small ridges. Different degrees of lung expansion cause variations of the surface topography. The morphology of certain surface features is examined in detail. Several methods of drying the specimens are compared.
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    Comparative scanning electron microscope study of boar, bull and ram spermatozoa (1975)
    Springer
    Cell & tissue research 161 (1975), S. 329-341 
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    ISSN: 1432-0878
    Keywords: Spermatozoa ; Boar, bull, ram ; Surface ultrastructure ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé La morphologie comparée des spermatozoïdes éjaculés de Verrat, Taureau et Bélier a été étudiée au microscope à balayage. Le sperme lavé est fixé dans le glutaraldéhyde ou le mélange acide picrique-formaldéhyde-glutaraldéhyde. Les échantillons sont le plus souvent désséchés par la méthode du point critique (Fréon) sur un filtre et aussi dans l'air sur une lamelle de verre. La tête des spermatozoïdes de ces trois espèces présente la même forme en pagaie aplatie formée de trois régions principales: les deux segments, antérieur, entouré d'un épaississement marginal, et équatorial de l'acrosome et la région postacrosomique. La plupart des differentiations de la lame postacrosomique décrites en microscopie électronique à transmission sont visibles à travers la membrane plasmique, particulièrement après dessication à l'air. La morphologie superficielle du cou et des différentes parties du flagelle est aussi observable. Des différences spécifiques sont mises en évidence: chez le verrat seulement, par exemple, la surface de l'acrosome apparaît granuleuse, et aucune bordure antérieure dentelée de la lame postacrosomique n'est visible. La microscopie à balayage permet d'observer les grands traits et de fins détails de la morphologie superficielle d'un échantillon de sperme et aussi d'étudier les effects de traitements sur des spermatozoïdes (congélation, extraction de l'acrosome).
    Notes: Summary The comparative ultrastructure of ejaculated boar, bull and ram spermatozoa is studied by scanning electron microscopy. After washing, the spermatozoa are fixed in glutaraldehyde or in picric acid-formaldehyde-glutaraldehyde mixture. Samples are prepared either by critical point drying (Freon) on Millipore filters or by air drying on glass cover slips. In all the species studied, three regions may be distinguished in the paddle-shaped head of the sperm: an anterior segment (surrounded by the marginal thickening) and an equatorial segment constituting together the acrosome, and the postacrosomal region. Most of the feature of the postacrosomal lamina described in transmission electron microscopy are visible through the plasma membrane, particularly after air drying. The surface morphology of the neck and of the different segments of the flagellum is also evident. Some species differences are encountered, e.g. rough surface of acrosome and absence of serrations in postacrosomal lamina of boar spermatozoa only. The techniques employed result in good general morphology and fine resolution of surface detail of the sperm samples; they also permit analysis of spermatozoa treated by freezing or submitted to acrosomal extraction.
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    A combined scanning and transmission electron microscopic study and electron probe microanalysis of human pineal acervuli (1976)
    Springer
    Cell & tissue research 174 (1976), S. 129-137 
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    ISSN: 1432-0878
    Keywords: Pineal organ, human ; Acervuli ; Scanning electron microscopy ; Transmission electron microscopy ; Electron probe microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Untreated, decalcified and trypsinized acervuli from human pineal bodies were studied with the scanning and transmission electron microscope as well as by electron probe microanalysis. The mulberry-like acervuli are composed of a various number of spherical lobes (135–800 μm) between which clustered groups of globuli (4–14 urn in diameter) are observed. The acervular lobes are very probably formed by an aggregation of these globuli. Small round particles 125–500 Å in diameter are observed on the surface of the pineal concretions. These are not influenced by either decalcification or trypsin treatment. The acervular mineral corresponds morphologically to hydroxyapatite. The electron probe microanalysis reveals the existence of calcium and phosphorus as main components of the acervuli. Small quantities of magnesium and strontium were also detected.
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    Scanning electron microscopy of dissociated pancreatic acinar cell surfaces (1977)
    Springer
    Cell & tissue research 176 (1977), S. 493-504 
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    ISSN: 1432-0878
    Keywords: Pancreas ; Acinar cells ; Cell surface ; Dissociation ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pancreatic acinar cell surfaces have been studied by SEM with a dissection technique and correlated with results obtained by TEM. The SEM results demonstrate characteristic arrangement of microplicae which in some areas are densely packed. In many areas, the microplicae are distributed in such a manner that they create zones with typical geometrical shapes and show a relatively smooth surface. These smooth areas may coincide, as indicated by correlated TEM results, with the limits of intimate contact between adjacent acinar cells which, in turn, represent part of the junctional complex. Another aspect revealed by these SEM preparations concerns the presence of groups of densely packed microplicae, arranged in regular rows and distributed along some grooves and/or infoldings of the cellular surface. On the basis of SEM and TEM information, it is likely that these structures correspond to intercellular (and possibly, in some cases, intracellular) canaliculi which topographically form a kind of extensive microlabyrinthine arrangement running along all the cell sides. One final point revealed by fractured samples concerns the finding of spherical zymogen droplets within the vesicles of the Golgi complex. Because in many scanning images these vesicles appear connected by small openings, it is suggested that they may represent a system of intercommunicating chambers (vacuoles) through which the zymogen droplets can be continuously accumulated and discharged into the acinar lumen.
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    The third ventricle of monkeys (1977)
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    Cell & tissue research 177 (1977), S. 307-316 
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    ISSN: 1432-0878
    Keywords: Third ventricle ; Mature monkeys ; Scanning electron microscopy ; Ependyma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Surface features of the ependymal lining of the third ventricle in mature male and female monkeys have been investigated with scanning electron microscopy (SEM). Broad aspects of third ventricular morphology from three species of monkey are similar regardless of sex. The lateral walls are heavily ciliated whereas the ventral floor and most ventral parts of the lateral walls are not. Clumps of cilia on the lateral walls are so dense that underlying surface details are usually obscured. There is a transition zone between the ciliated lateral wall and nonciliated ventral floor. The floor and lower part of the lateral walls of the third ventricle exhibit a characteristic polygonal pattern upon which surface specializations such as microvilli, blebs and polymorphous membrane protrusions are superimposed. Ependyma of the choroid plexus of the third ventricle also display membrane specializations. Supraependymal cells are more visible in nonciliated regions.
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    The surface fine structure of the bovine subcommissural organ (1975)
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    Cell & tissue research 163 (1975), S. 125-132 
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    ISSN: 1432-0878
    Keywords: Bovine subcommissural organ ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The bovine subcommissural organ was studied by using scanning electron microscopy. The most prominent finding was the existence of protruded and dilated endings of the ependymal cells. The majority of these cells were ciliated with two or more cilia; only a few unciliated cells were seen. Some pore-like structures were also seen on the surface. From the functional point of view, the most interesting finding was an amorphous heterogeneous material on the subcommissural ependyma. Especially in the caudal part of the organ this material accumulated in abundance. No real filamentous structures such as Reissner's fibre could be seen, however, it was assumed that the heterogeneous material corresponds to this formation. No supraependymal neurones were demonstrated.
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    Neuronal migration during the early development of the cerebral cortex (1975)
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    Cell & tissue research 163 (1975), S. 313-325 
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    ISSN: 1432-0878
    Keywords: Neurogenesis ; Cerebral cortex ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Fixed cerebral vesicles of mouse foetuses were fractured and examined with the scanning electron microscope. This method provides a study of the three dimensional developmental features of the pseudostratified columnar epithelium up to the formation of the early cortex plate. Matrix cells are a cell population of homogeneous shape, however, mitotic cells are easily identified by their spherical form. The external surface of the brain is formed by the closely packed end feet of these cells covered by a basal membrane. The formation of the cortical plate is the result of a continuous cell migration in columnar arrangement towards the pia. Glioependymal cells extend along the whole brain wall and most likely provide guidance for the migrating cell cords. The formation of the so-called migratory zone is a consequence of the growth of the basal and the horizontal prolongations of emigrating cells. The significance of the cell to cell contacts for the neuronal migration processes is discussed.
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    Morphology, morphometry and electron microscopy of HeLa cells infected with bovine Mycoplasma (1976)
    Springer
    Cell & tissue research 170 (1976), S. 1-16 
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    ISSN: 1432-0878
    Keywords: Tissue culture cells ; Mycoplasma ; Light microscopy ; Transmission electron microscopy ; Scanning electron microscopy ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The host-parasite relationship of HeLa M cells artificially infected with a bovine species of Mycoplasma was studied by light microscopy, transmission electron microscopy and scanning electron microscopy. The use of morphometry to quantitate some of the findings was explored. The parasites were seen in locations extracellular to the cell surface. The detection of small numbers of organisms by light microscopy was well demonstrated by use of the fluorescent antibody technique. Scanning electron microscopy proved to be an excellent method for revealing the surface details of cell-parasite morphology. Ultra-thin sections showed that the parasites are aligned mostly parallel to the plasma membrane of the host cell but separated by a gap of 10 nm. Morphometry indicated an average of 69 organisms per cell surface occupying 1.7% of the surface area. An increase of 26% in diameter of the HeLa cells, possibly as a result of infection, was observed.
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    URL: http://dx.doi.org/10.1007/BF00220107
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    A scanning electron microscope study of the development of free axonal sprouts at the cut ends of dorsal spinal nerve roots in the rat (1976)
    Springer
    Cell & tissue research 170 (1976), S. 507-513 
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    ISSN: 1432-0878
    Keywords: Axons ; Scanning electron microscopy ; Neurones, afferent ; Nerve regeneration ; Spinal nerve roots
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat dorsal spinal nerve roots were cut and the tip on the ganglionic side of the cut was examined by scanning electron microscopy at 0, 7, 20 and 48 h after operation. Seven hours after cutting, free axonal sprouts had started to protrude from the cut end of the nerve. After 20 h the free sprouts were more profuse than at 7 h but were smaller and had a rougher surface. At both 7 and 20 h many of the sprouts consisted of a stalk 2–7 μm in diameter with a bulbous end 5–20 μm in diameter. A few branching sprouts were seen. At 48 h the sprouts were shrunken with a deeply furrowed surface. The significance of the surface structure of the sprouts is discussed.
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    URL: http://dx.doi.org/10.1007/BF00361708
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    Effects of castration and androgen-substitution on the morphology of the epididymal epithelium of the Japanese monkey, Macacus fuscatus, as revealed by scanning electron microscopy (1976)
    Springer
    Cell & tissue research 170 (1976), S. 515-521 
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    ISSN: 1432-0878
    Keywords: Epididymal epithelium ; Castration ; Androgen-substitution ; Japanese monkey ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The caput epididymidis from castrated and androgen-supplemented, castrated Japanese monkeys was observed with the scanning electron microscope. The experimental findings were compared with the normal structures in control animals. The epididymal lumen of control animals was lined by a tall, pseudostratified columnar epithelium possessing long, slender stereocilia which were densely arranged in a tuft-like form. After castration, the epididymal epithelium was decreased in height to one-fifth of controls. The stereocilia were also considerably reduced in length and in number, resulting in a flattened epithelial surface with polygonal boundaries. Frequent projection of a long, single cilium from an epithelial cell into the lumen was also a prominent feature in the epididymal ducts of the castrated animals. Administration of testosterone to the castrated animals resulted in almost complete recovery of the epididymal epithelium as well as regeneration of the stereocilia which regained a tuft-like arrangement.
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    The distal ommatidium of the compound eye of the housefly (Musca domestica): A scanning electron microscope study (1975)
    Springer
    Cell & tissue research 159 (1975), S. 379-385 
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    ISSN: 1432-0878
    Keywords: Compound eye ; Musca domestica ; Ommatidium ; Distal retinula ; Scanning electron microscopy ; Corneal lens ; Corneal pigment cell ; Pseudocone ; Semper cell ; Basement membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distal aspect of the housefly ommatidium was surveyed by the scanning electron microscope. Attention was directed to the somal eminence of the superior central cell and the lens to large pigment cell junction. The underside of each lens facet exhibits six hexagonally arranged incisures. Into each of these indentations are fitted several large pigment cells. This hexagonal indentation appears to be a tenacious anchorage. Two corneal pigment cells laterally encircle the pseudocone and at their proximal extension they enclose the Semper cells and neck of the retinula. The somal eminence of the superior central cell is about 10 μm from the base of the corneal pigment cell enclosure. Micrographs were used to construct a diagram of the ommatidium above the basement membrane. Suggestions are made as to the functional correlates of the observed ommatidial structures.
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    The aesthetes of chitons (1976)
    Springer
    Cell & tissue research 172 (1976), S. 379-388 
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    ISSN: 1432-0878
    Keywords: Chitons ; Receptors ; Shell surface ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The shells of the chitons Lepidochitona cinereus, Sypharochiton pelliserpentis, Amaurochiton glaucus and Onithochiton neglectus were examined by scanning electron microscopy. In all species the surface terminations of the megalaesthete and micraesthete organs could be identified lying flush with the shell surface, as well as, lenses of the shell eyes in O. neglectus. Periostracal debris and encrusting diatoms were a usual feature of the shell surfaces. The micraesthete subsidiary caps normally appear featureless, but the megalaesthete apical caps sometimes appear to be perforated. The reasons for this perforate appearance are discussed and it is concluded that it provides no evidence for the normal passage of substances out of or into the megalaesthete.
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    URL: http://dx.doi.org/10.1007/BF00399520
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    Light- and scanning electron microscopical studies of the hypothalamo-adenohypophysial portal vessels of the toad Bufo bufo (L.) (1975)
    Springer
    Cell & tissue research 162 (1975), S. 131-139 
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    ISSN: 1432-0878
    Keywords: Hypothalamo-adenohypophysial region Bufo bufo (L.) ; Portal vessels ; Methyl-methacrylate casts ; Light microscopy ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vascularization of the hypothalamo-adenohypophysial region of the toad Bufo bufo (L.) (Amphibia, Anura) was studied by means of light- and scanning electron microscopy. Special attention was given to the portal vascular system of the median eminence and the pars distalis. Course and arrangement of these vessels are described.
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    URL: http://dx.doi.org/10.1007/BF00223268
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    Surface fine structure of the globiferous pedicellariae of the regular echinoid, Psammechinus miliaris gmelin (1975)
    Springer
    Cell & tissue research 162 (1975), S. 377-385 
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    ISSN: 1432-0878
    Keywords: Globiferous pedicellariae ; Psammechinus miliaris ; Microvilli ; Chemoreceptor ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The globiferous pedicellariae of Psammechinus miliaris are described. Two fixation methods giving minimal distortion and rapid tissue hardening were adapted for soft tissue preparation for scanning electron microscopy. The pedicellarial valves are covered by a microvillous epithelium. The outer valve epithelial microvilli overlying red spherulocytes in the epidermis are characterized by a filament matrix radiating out from each microvillus. These microvilli may function in epidermal absorption of organic solutes. The inner valve microvilli are more densely packed and the filament matrix is absent. Ciliation is confined to the inner valve surface where the cilia are concentrated to form a distal sensory pad and sensory hillock. Behavioural evidence suggests a chemo- and mechanosensory role for the inner valve surface.
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    A scanning electron microscopic study of the rat liver sinusoid (1975)
    Springer
    Cell & tissue research 164 (1975), S. 371-385 
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    ISSN: 1432-0878
    Keywords: Kupffer cell ; Endothelial cell ; Sinusoid ; Liver ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The surface ultrastructure of Kupffer cells in the rat liver has been studied by scanning electron microscopy (SEM). The results demonstrate that Kupffer cells are both significantly different and clearly distinct from endothelial cells. Kupffer cells have neither pores (and/or “sieve plates”) nor fenestrations, all of which are present in endothelial cells. They possess a stellate shape, and only indirectly, with slender and irregular evaginations, contribute to the lining of the sinusoidal wall. Furthermore, the luminal surface in some areas contains a large population of short microvilli, microplicae and invaginations. These elements form a kind of microlabyrinth which may correspond to the “worm-like” structures described by transmission electron microscopy (TEM). In the present study, transition forms between endothelial and Kupffer cells were never found. On the contrary, considering the highly fenestrated nature of the endothelial cells, the Kupffer cells may, by ameboid movements, easily cross the overlapping barrier of the sinusoid and protrude into the lumen. Thus, acting as activated macrophages, the Kupffer cells might function to prevent the entrance of foreign material into the tissues of the liver through the fragile and highly fenestrated endothelium. Finally, the topographical reconstruction of the sinusoid by correlated SEM and TEM studies demonstrates that Kupffer cells, with their protruding cytoplasm and ability to extend into the lumen of the sinusoid, may actually change the caliber of the vessel, and thus function as a “sphincter” which causes a temporary arrest of the blood flow when the diameter of the sinusoidal lumen is reduced.
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    Scanning electron microscope observations on the muscle innervation of Oikopleura dioica fol (appendicularia, tunicata) with notes on the arrangement of connective tissue fibres (1975)
    Springer
    Cell & tissue research 164 (1975), S. 357-369 
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    ISSN: 1432-0878
    Keywords: Neuromuscular junctions ; Appendicularia (Oikopleura dioica) ; Connective tissue fibrils ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Critical point dried and fractured appendicularia of the species Oikopleura dioica have been examined in the scanning electron microscope. The dorsal nerve cord with ganglion cells and peripheral nerve fibres could easily be observed. Thick peripheral nerve fibres leave the nerve cord as bilateral pairs at constant intervals along the tail. Most of these fibres branch from the naked nerve cord, but some evidently originate in ganglion perikarya bulging out from the nerve cord itself. These paired peripheral nerves always have elaborate end-arborizations on the medial surface of the lateral muscle cells. They are accordingly interpreted as motor axons. Some thinner peripheral nerve fibres originate at irregular intervals from both the nerve cord and the ganglion cells. Due to the numerous extracellular fibrils that connect the bilateral layers of the epidermal fins and the muscle cells to each other, these thin nerve fibres can seldom be traced to their termination. A few ones can, however, be traced ventrally between the notochord and the muscle cells and seem to end in singular bulb-like expansions. Clusters of synaptic vesicles are present in transmission electron micrographs of such nerves, and they are accordingly believed to carry efferent impulses. The extracellular fibrils are arranged in a highly ordered pattern with thick bundles crossing the gap between the structures to be interconnected and with numerous radiating insertions on the surface of the tissues.
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    Scanning electron microscopy of bone cells in culture (1976)
    Springer
    Cell & tissue research 166 (1976), S. 65-70 
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    ISSN: 1432-0878
    Keywords: Collagen ; Bone ; Cell culture ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Embryonic and young rat bone cells have been grown in culture and examined in the scanning electron microscope (SEM). Compared with cells fixed in situ and taken directly from the animal, the cultured osteoblastic cells were smoother, flatter and more extensive and showed tighter intercellular contacts. Some matrix is formed in culture and undergoes at least partial mineralization as judged by the accumulation of Ca and P measured by energy dispersive x-ray analysis. Findings concerning the morphology of the collagen arrangement were indecisive. Some superficial cells, free of surrounding matrix, resembled osteocytes in normal in vivo bone. This may indicate that a proportion of the extracellular matrix produced by the cultured cells failed to polymerise into recognizable bone matrix, and that osteocytic morphology is not dependent upon the physical characteristics of the bone matrix.
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    Interaction of rabbit sperm and egg (1976)
    Springer
    Cell & tissue research 169 (1976), S. 277-287 
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    ISSN: 1432-0878
    Keywords: Rabbit gametes ; Cryofractography ; Scanning electron microscopy ; Transmission electron microscopy ; Zona pellucida
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rabbit ova fertilized in vitro were prepared for scanning electron microscopy by ethanol-cryofracturing and critical-point drying methods and were also embedded and sectioned for transmission electron microscopy. Study of a region of interaction between sperm and zona pellucida with scanning electron microscopy reveals the latter to be composed of a complex network of fibers interspersed with numerous pores. Transmission electron microscopy of the same region reveals a “typical” homogeneous composition of the zona pellucida. Ultrastructural observations of thin sections passing through the region of sperm-egg interactions or through other regions of the ovum or its investments reveals very little methodological distortion of the various intracellular organelles or matrix. Application of the procedures described provides not only an elucidation of surface detail but also reveals intracellular cytoplasmic information about the same specimen during in vitro fertilization.
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    Experimental study of changes in osteoblastic shape induced by calcitonin and parathyroid extract in an organ culture system (1976)
    Springer
    Cell & tissue research 169 (1976), S. 449-465 
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    ISSN: 1432-0878
    Keywords: Bone ; Osteoblasts ; Cell surface ; Cell shape ; Calcitonin ; Parathyroid extract ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neonate rat endocranial osteoblasts were cultured on their bone surfaces in control medium (CC) or medium to which either parathyroid extract (PTE) or calcitonin (CT) had been added for 2, 4, 8 or 24 h. Some were cultured for 24 h in CC, then for 2, 4, 8 or 24 h in either CT or PTE medium; or for 24 h in PTE, then for 2, 4, 8 or 24 h in either CC or CT; or 24 h in CT and 2, 4, 8 or 24 h in CC. The dorsal ruffling of the cells in CC was found to be suppressed by later culturing with PTE and the disoriented cells reorganized to form arrays of parallel cells. The effects of PTE were also reversed by CC or CT: the osteoblasts in the second culture (CC) lost elongation and order, and proceeded through a proliferative phase before exhibiting the ruffling form similar to a single CC 24 h culture. PTE-cultured osteoblasts showed an increase in cell overlap and contact so that a more competent barrier was formed separating the bone from the medium. In control or CT medium, however, intercellular gaps were greater than in vivo.
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    The Surface structure of isolated pancreatic islet cells (1975)
    Springer
    Cell & tissue research 164 (1975), S. 467-471 
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    ISSN: 1432-0878
    Keywords: Pancreas ; Islets ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The surfaces of isolated pancreatic islet cells were studied with the scanning and transmission electron microscopes. Islets were isolated from the pancreas of Wistar rats by collagenase treatment and were incubated either in glucose-free medium or in 300 mg% glucose for one hour. Immunoreactive insulin (IRI) in the media of both control and experimental preparations was assayed. Islets were then transferred to 4% glutaraldehyde, buffered with cacodylate, pH 7.4, and prepared for scanning and transmission electron microscopy. Cell masses average 200 μ in diameter. Alpha cells appear pyramidal in shape, are about 8 μ in diameter and appear in groups. Beta cells are round or oval in shape and have an average diameter of 10 μ. Glucose stimulation raised the IRI value tenfold and increased the number of blebs and other surface irregularities per unit area of beta cell surface. Comparison with transmission electron micrographs suggests that the blebs are related to the process of emiocytosis.
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    A critical reevaluation of the structure of the rat uriniferous tubule as revealed by scanning electron microscopy (1976)
    Springer
    Cell & tissue research 166 (1976), S. 91-100 
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    ISSN: 1432-0878
    Keywords: Kidney (rat) ; Uriniferous tubule ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of luminal surface of clearly identified portions of uriniferous tubules has been studied by scanning electron microscopy to elucidate some controversies concerning the topography of certain surface formations. The results show a characteristic pattern of the luminal surface in the region of Henle's loop, which was assumed by previous authors, to belong to the collecting tubule. Furthermore it is demonstrated that no cilia are present within the terminal portion of the collecting tubules.
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    Aggregation-induced alterations in fibroblast morphology (1976)
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    Cell & tissue research 174 (1976), S. 499-518 
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    ISSN: 1432-0878
    Keywords: Fibroblast ; Human ; Transmission electron microscopy ; Scanning electron microscopy ; Aggregation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The different stages during aggregation of diploid human skin fibroblasts have been examined by transmission and scanning electron microscopy. As a result of aggregation, fibroblasts form a complex tissue configuration. Numerous intercellular junctions can be observed, while the cells remain polygonal and do not develop an organised intracellular cytoskeleton. Cell division occurs only rarely. After aggregation, signs of progressive auto-digestion develop. Adhesion to a substrate results in outgrowth of the cells and monolayer formation, even when extensive cell damage had occurred. The morphology of fibroblasts in aggregates and in the monolayers, from which they were derived, is compared and the contribution of the aggregate system to the study of fibroblast behavior is discussed.
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    Scanning electron microscopy of the glomerular filtration membrane in the rat kidney (1976)
    Springer
    Cell & tissue research 166 (1976), S. 299-314 
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    ISSN: 1432-0878
    Keywords: Renal glomerulus (Rat) ; Endothelial cells ; Blood capillaries ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The rat kidney was perfused with saline and glutaraldehyde, treated with Murakami's tannin-osmium impregnation method, ethanol-freeze cracked and dried by the critical point method. Gold-palladium evaporated specimens were observed in a field-emission scanning electron microscope. The glomerular filtration membrane, fractured in different planes was observed with the following results: 1. Adjacent pedicles originate from different podocytes. No interpedicular bridges of apparent cytoplasmic nature could be found. 2. The basement membrane, in grazing fractures shows a horizontally layered architecture. 3. The attenuated endothelial sheet (lamina fenestrata) is divided into compartments, which we suggest should be called “areolae fenestratae”, by cytoplasmic crests radiating from the nucleated portion of the endothelial cell. A crest also occurs along the cell margin, which contacts a similar crest at the margin of the adjacent cell. 4. The pores in the areolae fenestratae are variable in size (30−150 nm diameter). A knob-like projection from the apparently naked basement membrane is found in a portion of the pores. 5. Numerous microvilli may occur on the endothelium. Some of them anastomose and fuse with one another to form a net whose meshes appear identical with the endothelial pores. Domes and shelves formed of a fenestrated cytoplasmic sheet also occur above the ordinary level of the endothelial lining. A hypothesis implicating microvilli in partial renewal of the endothelial sheet is proposed. This study was assisted by Mr. K. Adachi of the SEM Laboratory at the Niigata University School of Medicine.
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    Three-dimensional development of luminal projections and junctional complexes in the developing central nervous system blood vessels of the rat (1977)
    Springer
    Cell & tissue research 175 (1977), S. 541-549 
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    ISSN: 1432-0878
    Keywords: Blood vessels ; High voltage electron microscopy ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The luminal surface features and Junctional complexes from developing blood vessels in the rat central nervous system have been studied by high-voltage electron microscopy and scanning electron microscopy. Developing blood vessels exhibit three types of luminal projections; marginal folds or ridges at Junctional complexes, ridges not at Junctional complexes and microvilli. Both types of ridges are associated with troughs or depressions in the luminal surface of the endothelial cell. Those ridges not associated with Junctional complexes take part in the production of enclosed tunnels in the endothelial cell cytoplasm. Fusion of the external leaflets of Junctional complexes between adjacent endothelial cells occurred, initially, near the luminal surface of the blood vessel with other small fusion sites forming in the direction of the basal lamina secondarily. Further fusion activity to produce the zonula occludens type junction appeared to spread outwards from the smaller fusion sites.
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    Classification of human placental villi (1979)
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    Cell & tissue research 200 (1979), S. 409-423 
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    ISSN: 1432-0878
    Keywords: Human placenta ; Classification of villi ; Histology ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The classification of human placental villi was reviewed on the basis of material prepared by means of special methods. The material from in situ normal-term placentae was biopsied by aspiration into glutaraldehyde. The classification was made on the basis of light-microscopic observations of semithin sections, reconstructions from serial sections, and scanning-electron micrographs. The peripheral villous tree is roughly divided into stem (ramuli), intermediate and terminal villi. The intermediate villi may be further subdivided as mature and immature types, which are found between the stem and terminal villi. Some of the terminal villi possess a local specialization described as the neck region. The histological characteristics and the branching pattern of each type are described, and the basis of the proposed classification is discussed.
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    A scanning electron microscopic study of rabbit spermatozoa in the female reproductive tract following coitus (1975)
    Springer
    Cell & tissue research 163 (1975), S. 29-44 
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    ISSN: 1432-0878
    Keywords: Spermatozoa ; Capacitation ; Uterus ; Acrosome Reaction ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The surface morphology of rabbit spermatozoa, fixed in situ (female reproductive tract) and prepared for scanning electron microscopy by critical point drying, was studied for as many as 36 hours post coitum. The findings demonstrate that 1) spermatozoa in the reproductive tract following coitus exist as a heterogenous, morphological population and 2) with time, shifts within this population from one predominant morphology to another take place. In the fresh ejaculate, most spermatozoa have intact surfaces free of membranous disruptions. With time, a process of labilization (denudation) of the membranes covering the acrosomal region occurs in a progressively larger proportion of spermatozoa. The labilization originates by a process of vesiculation and/or vacuolation and leads to the appearance of a series of small fenestrations or perforations of the surface membranes. The perforations coalesce, and gradually larger areas of the surface membranes are eroded such that by 15 hours post coitum, the outer acrosomal membrane, as well as other acrosomal areas, are to varying degrees, directly exposed to the uterine milieu. Secretory granules, picked up by cilia and transferred to the spermatozoa become localized over the acrosomal region shortly after coitus. The possible significance of these time-dependent, morphological events with the phenomena of capacitation and the “true” and “false” acrosome reactions are discussed.
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    URL: http://dx.doi.org/10.1007/BF00218589
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    The reality of arthropod cuticular laminae (1975)
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    Cell & tissue research 163 (1975), S. 411-413 
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    ISSN: 1432-0878
    Keywords: Cuticle ; Laminae ; Arthropod ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Examination of etched pyramids of decapod crustacean cuticles with the scanning electron microscope indicates that laminae are continuous around the angles of the pyramids. This observation is in direct contrast to the result expected on Bouligand's (1965, 1971) hypothesis and suggests that laminae may be real structures.
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    Photoreceptor-like outer segments in the pineal organ of the lovebird, Uroloncha domestica (Aves: Passeriformes) (1977)
    Springer
    Cell & tissue research 182 (1977), S. 139-143 
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    ISSN: 1432-0878
    Keywords: Pineal organ ; Uroloncha domestica (Aves, Passeriformes) ; Photoreceptor-like cells ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the pineal organ of the lovebird, Uroloncha domestica, bulbous, cup-shaped and elongated outer segments of photoreceptor-like pinealocytes are demonstrated by scanning electron microscopy. These scarce outer segments, 4–11 μm in length, extend into the pineal lumen. The present structural observations speak in favor of photosensitive pinealocytes in the pineal organ of Uroloncha domestica. The relation of the photoreceptor-like pinealocytes to acetylcholinesterase-positive nerve cells and a nervous connection between the pineal and the brain indicate that the pineal organ of this passeriform species may be the site of neuroendocrine and photoreceptive functions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222062
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    Surface morphology of lens fibers from eyes of normal and microphthalmic (Browman) rats (1976)
    Springer
    Cell & tissue research 167 (1976), S. 425-438 
    Details
    ISSN: 1432-0878
    Keywords: Scanning electron microscopy ; Crystalline lens ; Microphthalmos
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The surface features of cortical fibers from lenses of normal adult rats and microphthalmic rats of the Browman strain have been studied by scanning electron microscopy. In the normal lenses, superficial cortical fibers follow a straight course from inner to outer pole whereas the deeper cortical fibers, while straight near the poles, pursue an undulating or zig-zag course at and near the equator. Almost all of the fibers are hexagonal in cross section and all fibers throughout their entire length are bound by interdigitating processes at each corner of the hexagon to corners of two adjacent fibers. Some fibers are also affixed by a single row of ball and socket junctions located on their broad outer and inner surfaces. Lens fibers from Browman rats display both minor and major abnormalities. These included segmentation, formation of incisures and lateral protrusions, corrugation and villous-like alteration of the broad fiber surface and development of parallel ridges on broad surfaces in a basket-weave pattern.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215175
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    Scanning electron microscopy of photoreceptor cells in the light- and dark-adapted retina of Haplochromis burtoni (Cichlidae, Teleostei) (1976)
    Springer
    Cell & tissue research 175 (1976), S. 123-130 
    Details
    ISSN: 1432-0878
    Keywords: Retina ; Haplochromis burtoni ; Photoreceptor cells ; Light-adaption, dark-adaption ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The photoreceptor layer in the retina of Haplochromis burtoni (Cichlidae, Teleostei) was studied by scanning electron microscopy. Three types of receptors were identified: rods, single-cones and double-cones. The three-dimensional arrangement of these photoreceptors is described in the light- and dark-adapted retina. The surface of the inner segment of the photoreceptor cells displays fine vertical fissures which give rise to slender processes. These so called calycal processes which are of different lengths in rods and cones, surround the beginning of the smooth-surfaced outer segment. The myoid, the contractile part of the receptor, which is located beneath the ellipsoid, was examined in the single-cones of the dark-adapted retina. It is a slender structure with surface infoldings. The myoid, studied by transmission electron microscopy, contains bundles of parallel myofilaments, which are thought to be contractile.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220828
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    The salivary glands of the cockroach Nauphoeta cinerea (Olivier) (1978)
    Springer
    Cell & tissue research 187 (1978), S. 525-534 
    Details
    ISSN: 1432-0878
    Keywords: Salivary glands ; Insects ; Innervation ; Light microscopy ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the salivary gland of the cockroach Nauphoeta cinerea (Olivier) has been investigated with the use of light and scanning electron microscopy. Light microscopy of methylene blue stained glands reveals the presence of a dual innervation arising from the ventral nerve cord and the stomodeal nervous system; the principal innervation is that from the ventral nerve cord which passes to the gland via the reservoir ducts. Branches of these nerves form a plexus on the acinar surface, the axons of which exhibit swelling at irregular intervals. The presence of this surface plexus and the axonal swellings was confirmed by scanning electron microscopy both in normal glands and in those in which the basal lamina had been removed by means of an HCl-collagenase digestion method. No acinar plexus was seen to be formed by branches of the stomatogastric nerve that were associated with the gland. However, other branches of this nerve were clearly connected with a complex network of multipolar neurones on the surfaces of the anterior regions of both salivary reservoirs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229617
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    The human rete testis (1978)
    Springer
    Cell & tissue research 189 (1978), S. 409-433 
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    ISSN: 1432-0878
    Keywords: Rete testis ; Human ; Histophysiology ; Chordae retis ; Scanning electron microscopy ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The human rete testis was examined with regard to 1) the number and distribution of entrances of seminiferous tubules, 2) the light microscopic topography and 3) details of the passages as revealed by scanning and transmission electron microscopy. In a newborn 1474 entrances were counted, approximately 50 % entering from the right and 50 % from the left of the central long axis. Three major subdivisions of the rete were distinguished and described: a septal (or interlobular) part represented by tubuli recti, a tunical (or mediastinal) part which is a true network of channels, and an extratesticular part characterized by dilatations (up to 3 mm wide) which we have called bullae retis. In SEM, cylindrical strands running from wall to wall in the tunical and extratesticular rete spaces are a prominent feature. We have called these chordae retis. They are covered by epithelium and are 5–40 μm wide and 15 to more than 100 μm long. They contain a peculiar tissue consisting of central myoid cells in a fibroelastic matrix. The smaller chordae are avascular. In the light of these findings the rete is interpreted as a highly complex myoelastic sponge. Its function is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209130
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    Model of skin vascularization in Rana esculenta L.: Scanning electron microscopy of microcorrosion casts (1978)
    Springer
    Cell & tissue research 191 (1978), S. 539-548 
    Details
    ISSN: 1432-0878
    Keywords: Frog skin ; Respiratory capillaries ; Capillary networks ; Microcorrosion casts ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Microcorrosion casts of blood vessels in the skin of Rana esculenta L. were examined by means of scanning electron microscopy with particular reference to the subepidermal network of respiratory capillaries. Due to the fact that arteries and veins lie in the deeper layers of the stratum spongiosum of the corium, the respiratory vessels form a morphologically homogeneous network. Functionally, however, this network is subdivided into small areas with a centripetal direction of blood flow. The deep capillary net, situated at the base of the stratum compactum of the corium, is not so dense as the respiratory network and does not directly communicate with it. Alveolar glands of the skin have no effect on the distribution of capillaries in the two networks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219816
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    Scanning electron microscopy of peripheral blood leukocytes of the chicken (1979)
    Springer
    Cell & tissue research 204 (1979), S. 147-153 
    Details
    ISSN: 1432-0878
    Keywords: Granulocytes ; Lymphocytes ; Monocytes ; Scanning electron microscopy ; Chicken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Polymorphonuclear leukocytes, e.g., neutrophilic granulocytes, were enriched from heparinized blood by a Ficoll-step-gradient centrifugation procedure. Scanning electron microscopy (SEM) revealed a surface morphology of narrow ridge-like profiles and small ruffles with occasional microprocesses. Mononuclear leukocytes were isolated by centrifugation over a Ficoll-Metrizoat gradient. The lymphocytes showed varying numbers of microvilli of different length, size and shape. B lymphocytes, characterized by their capability of “sheep red blood cell (SRBC)-rosette formation”, displayed a similar surface morphology. Completely smooth lymphocytes, described in the literature as T lymphocytes, could not be detected, although many lymphocytes with few microprocesses were observed. Thus, SEM is not a useful tool for distinguishing between B and T lymphocytes in the peripheral blood of chickens. Monocytes were characterized by prominent membrane-like ruffles, but in some cases they closely resembled granulocytes. An influence of the various separation media on the surface morphology of the isolated cells could not be detected when compared with cells isolated by the buffy-coat method.
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    URL: http://dx.doi.org/10.1007/BF00235171
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    Scanning electron microscopy of the renal corpuscle of the mesonephros in the lamprey, entosphenus japonicus martens (1978)
    Springer
    Cell & tissue research 187 (1978), S. 105-113 
    Details
    ISSN: 1432-0878
    Keywords: Mesonephros ; Lamprey ; Renal corpuscle ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The renal corpuscle of the lamprey mesonephros was studied under the scanning electron microscope. Bowman's capsules with individual spaces are chockshaped sacs closely packed together along a medial artery. The lateral walls of the capsules are apposed to those of neighbouring capsules. Glomerular capillaries from the medial artery extend radially between the apposed walls of neighbouring Bowman's capsules. Bulgings of capillaries into the capsular space are associated with mesangial folds of the capsular epithelium. The transitional zone of the visceral layer with podocytes and the parietal layer of squamous epithelium is bounded by linearly arranged rod-shaped epithelial cells. Apertures of the urinary tubule are lined by cells equipped with a fascicle of cilia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220622
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    Cytochalasin B and water transport (1978)
    Springer
    Cell & tissue research 188 (1978), S. 375-388 
    Details
    ISSN: 1432-0878
    Keywords: Urinary bladder ; Skin ; Toad, frog ; Water flow ; Na transport ; Vasopressin ; Cytochalasin B ; Microfilaments ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A morpho-functional study of the effects of cytochalasin B (CB) on Na and water transport was made in amphibian epithelia. The functional studies confirmed the dissociation of the natriferic and hydrosmotic effects of vasopressin in toad urinary bladders exposed to CB and showed in addition that the block of the hydrosmotic effect was reversible and could still be induced in epithelia maximally stimulated with the hormone. Scanning electron microscopy revealed that CB, per se, did not alter the apical surface of the bladders. An almost total loss of microvilli of granular cells was seen, however, if CB was associated with vasopressin and an osmotic gradient. The results suggest two points: a) the block of the hydrosmotic flow induced by CB is due to factors beyond the apical membrane; b) microfilaments may be important mechanochemical transducers in the chain of events leading to the hydrosmotic effect of vasopressin.
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    URL: http://dx.doi.org/10.1007/BF00219779
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    On the development of midpiece mitochondria of mouse spermatozoa (1979)
    Springer
    Cell & tissue research 199 (1979), S. 349-352 
    Details
    ISSN: 1432-0878
    Keywords: Spermatozoa ; Mitochondria ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary As seen by scanning electron microscopy, the mitochondrial helix in the developing midpiece of mouse testicular spermatozoa is dextral in direction and consists of spherical mitochondrial units arranged in an orderly array of four units per gyre: three appearing in face view and a fourth hidden from view at the back of the gyre. As the spermatozoa mature, the dextral helix is transformed into a sinistral helix. Its constituent spherical mitochondria either change direction abruptly without changing shape; or having first become semilunar or diamond-shaped, they change direction gradually. Mitochondrial division follows the change in helical pitch producing a double sinistral helix. The spherical (or semilunar/diamond-shaped) mitochondria presumably elongate to form the units of the mature midpiece.
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    URL: http://dx.doi.org/10.1007/BF00236144
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    Scanning electron microscopic study of the freeze-fractured pineal body of the rat (1979)
    Springer
    Cell & tissue research 201 (1979), S. 129-135 
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    ISSN: 1432-0878
    Keywords: Pineal body ; Freeze-fracturing ; Scanning electron microscopy ; Wistar rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The three-dimensional ultrastructure of the pineal body of the rat is described on the basis of freeze-fractured preparations. The pineal capsule consists of irregular cells with very flat and perforated processes. Through these openings, extremely branched canaliculi, extending to almost every pineal cell, communicate with the tissue compartment outside the organ. The pericapillary spaces contain, in juxtaposition with capillaries of the fenestrated type, nerve fibers as well as a flocculent granular and filamentous material of unknown origin and chemical nature.
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    URL: http://dx.doi.org/10.1007/BF00238052
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    Scanning electron microscopy of the wall of the third ventricle in the brain of Rana temporaria. Part IV. (1979)
    Springer
    Cell & tissue research 203 (1979), S. 53-64 
    Details
    ISSN: 1432-0878
    Keywords: Brain ; Third ventricle ; Rana temporaria ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The surface specializations of the wall of the third cerebral ventricle of Rana temporaria were investigated with the scanning electron microscope. These specializations can be divided into three types: cilia, large bulbous protrusions, and microvillus-like protrusions. Most parts of the ventricular surface are densely ciliated. In contrast, other regions are either scantily ciliated or devoid of cilia. Four areas of the ventricular surface are studded with numerous large bulbous protrusions. These large protrusions can be divided into two types: One type consists of intraventricular end bulbs of dendrites of secretory neurons. The other type is represented by large cytoplasmic extensions of ependymal cells. In the third ventricle of Rana, microvillus-like surface specializations of ependymal cells are ubiquitous structures. Generally, filiform protrusions of varying length are the predominant type. The microvillus-like specializations are transient structures, the number of which varies according to different physiological states of the ependymal cells.
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    URL: http://dx.doi.org/10.1007/BF00234328
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    The surface fine structure of the ependymal lining of the lateral ventricle in rats with hereditary hydrocephalus (1977)
    Springer
    Cell & tissue research 179 (1977), S. 121-129 
    Details
    ISSN: 1432-0878
    Keywords: Lateral ventricle, rat ; Hydrocephalus ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ependyma of the lateral ventricle of rats with hereditary hydrocephalus was studied using scanning electron microscopy. Normal rats from the same litters were used as control animals. The surface morphology of the lateral ventricle of normal rats corresponded to results reported by other authors. The most prominent changes in the surface morphology of the ependyma of the hydrocephalic rats were seen in the cilia. They were shortened, fewer in number and clumped or matted. The surface of the ependymal cells was flattened and contained small, irregular projections. The number of large supraependymal cells, regarded as neurons, appeared to have diminished in the hydrocephalic rats. The number of supraependymal macrophages was greatly increased in these rats, suggesting the existence of an ependymitis.
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    URL: http://dx.doi.org/10.1007/BF00278467
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    Ciliary function of the frog oro-pharyngeal epithelium (1977)
    Springer
    Cell & tissue research 178 (1977), S. 267-278 
    Details
    ISSN: 1432-0878
    Keywords: Ciliated epithelium, frog ; Cilia ; Coordination ; Mucous transport ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The palate epithelium of the frog was examined by scanning electron microscopy, light microscopy and high speed cine micrography. The cilia remain stationary for much of the time in the end-of-effective stroke position. Each beat cycle begins with a forwardly-directed recovery stroke lasting about 60 ms, followed by an effective stroke towards the oesophagus lasting about 12 ms. Activity can often be correlated with the presence of mucus, which is carried as strands on the tips of the ciliary effective strokes whilst the recovery strokes move beneath the mucus. Coordination of ciliary activity was very variable; local antiplectic metachrony of the recovery strokes could almost always be seen, and on very active epithelia effective strokes were associated with approximately diaplectic waves (either to left or right), but any particular pattern of coordinated activity was transient and quickly transformed to another pattern. Beating and coordination of these short cilia were compared with those of cilia propelling water.
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    URL: http://dx.doi.org/10.1007/BF00219053
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    Surface morphology of taste buds in catfish barbels (1977)
    Springer
    Cell & tissue research 178 (1977), S. 375-384 
    Details
    ISSN: 1432-0878
    Keywords: Taste buds ; Fishes ; Neuroepithelium ; Microvilli ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary External taste buds abound on barbels of the adult catfish Corydoras arcuatus. When examined by scanning electron microscopy, they are visualized as a series of punctate, conical elevations projecting from the general surface epithelium. All taste buds were found to be of one type. Both their external and internal surface features could be clearly elucidated on intact barbels and in barbels fractured transversely at various positions along their length. An extensive nerve terminal network penetrates the base of each taste bud. Two populations of elongated cells bearing prominent microvilli project through the central pore at the tip of each bud. One set of microvilli is thicker, longer and more club-shaped than its counterpart. While both are randomly distributed within each central pore, the small, short microvilli appear to outnumber the larger ones. A third population of cells, devoid of any apical microvilli, was also seen in some of the taste buds examined internally. These cells do not project to the external surface and are interpreted as “basal” cells described in previous light and transmission electron microscope studies of taste buds in other vertebrate species. The functional significance of some of these morphological findings is discussed.
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    URL: http://dx.doi.org/10.1007/BF00218701
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    Vascularization of the pars distalis of the hypophysis in the toad, Bufo bufo (L.) (Amphibia, Anura) (1977)
    Springer
    Cell & tissue research 179 (1977), S. 1-10 
    Details
    ISSN: 1432-0878
    Keywords: Hypophysis, pars distalis ; Bufo bufo (L.) ; Vascularization ; Corrosion casts ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vascularization of the pars distalis of the hypophysis of the toad, Bufo bufo (L.), was studied by the traditional method of injecting a mixture of India-ink and gelatine into the circulatory system of the head via the arteria carotis communis. Further, methyl-methacrylate corrosion casts of the brains were made; the hypothalamo-adenohypophysial region of these corrosion casts was studied with the scanning electron microscope. The results showed that the portal vessels which arise from the median eminence do not supply distinct areas in the pars distalis as is supposed by the point-to-point-hypothesis. The portal vessels enter the ventro-median region of the pars distalis and branch off into a three-dimensional network of the secondary capillary plexus of the pars distalis. The plexus is made up mostly by four- to six-sided meshes. This angioarchitecture guarantees an optimal supply of the glandular cells of the pars distalis with nutritional factors and releasing hormones, on the one hand, and facilitates the removal of the hormones which are released by these cells, on the other hand. The venous drainage of the pars distalis is exerted mainly by two large veins, which bilaterally leave the dorso-lateral region (venous pole) of the pars distalis and by a few small veins, which drain into the wide, sinus-like vessel, which curves around the dorso-caudal region of the pars distalis and joins bilaterally the vena hypophysea transversa.
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    URL: http://dx.doi.org/10.1007/BF00278459
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    A scanning electron microscopic survey of the brain ventricular system of the female armadillo (1977)
    Springer
    Cell & tissue research 183 (1977), S. 531-539 
    Details
    ISSN: 1432-0878
    Keywords: Brain ventricles ; Armadillo ; Ependyma ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The scanning electron microscope was used to survey the brain ventricular system of the female armadillo (Dasypus novemcinctus) with emphasis on the third ventricle. The walls of the lateral ventricles, aqueduct, and fourth ventricle are covered by long cilia. In the lateral ventricle, the cilia are arranged in groups; but in the aqueduct and fourth ventricle, they are evenly placed over the cellular surfaces. The ependymal cells of the third ventricle are densely ciliated except for the organum vasculosum and infundibular recess. The non-ciliated luminal surface of these areas has a pebblestone appearance punctuated by numerous microvilli and two types of supraependymal cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225665
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