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  • 1
    Electronic Resource
    Electronic Resource
    Scanning Electron Microscopy of Developmental Stages of Malpighamoeba mellificae Prell in the Honey Bee (1985)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 32 (1985), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Primary trophozoites of Malpighamoeba mellificae Prell in the process of penetrating the cell membrane were found among the brush border of epithelial cells of the midgut of Apis mellifera L. They were long and slender with an average diameter of 3.68 μm. Their surfaces had some wrinkles and the cytoplasm contained some vesicles. Secondary trophozoites were found in the lumen of Malpighian tubules. Their size was variable and their shapes were highly irregular; some had pseudopodia. The smooth surface of trophozoites possessed numerous small protrusions and pits. Mature cysts were small and oval-shaped; they measured from 2.65 times 3.62-3.4 times 4.6 μm. Their surface was usually smooth but some had wrinkles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1985.tb03027.x
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructural Architecture and Organization of the Spore Envelope during Development in Thelohania bracteata (Strickland, 1913) after Freeze-Etching (1973)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 20 (1973), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: An ultrastructural study was made of the spore envelope during development in the microsporidan, Thelohania bracteata. The frozen-etched outer (convex) face of the relatively thin spore coat in the earliest immature stage of development has a granular structure in regular array. The inner (concave) face bears particles as well as depressions arranged in a net-like pattern. The mature spore coat has a substructure of numerous microfibers, ∼8 nm in diameter, arranged in a matrix and forming thin layers which run parallel to the spore surface. The mature spore coat possesses both outer and inner limiting layers. The outer (convex) face of the outer limiting layer is granular. The convex face of inner limiting layer bears many particles as well as many long, narrow depressions. The concave face of the inner limiting layer carries many stud-like projections, ∼40 nm long and 30 nm high, which are complementary to the depressions observed on the convex face. In addition, the concave face has subunits ∼15 nm in diameter, apparently arranged in a hexagonal pattern with a center to center distance of ∼18 nm. The change in size of these projections, depressions, and subunits presumably is related to spore maturation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1973.tb03586.x
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  • 3
    Electronic Resource
    Electronic Resource
    Fine Structure of Developing Spores of Thelohania bracteata (Strickland, 1913) (Microsporida, Nosematidae) Emphasizing Polar-Filament Formation (1972)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 19 (1972), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. In the microsporidian, Thelohania bracteata, the polar filament, as it starts to develop in the sporoblast, apparently receives material synthesized by the granular endoplasmic reticulum and Golgi vesicles. In immature spores many dilated sacs are observed in areas where there is less endoplasmic reticulum. These sacs, that persist into the almost mature spore, are probably Golgi-type vesicles and may be related to the formation of the spore coat. The polar filament of the mature spore possesses 8 coils and in cross section or cross-fractured face the electron-dense central portion of the polar filament contains a tubular structure, ringed by 12–14 cylindrical structures. In thin sections, an electron-lucid zone is observed between the core and membrane of the polar filament. The polar filament runs through the highly laminated polaroplast which occupies the anterior portion of the spore. In cross-fractured face the lamellae of the polaroplast are arranged like the petals of a flower. The basal portion of the polar filament is enlarged, appearing arrow-shaped in thin sections and pear-shaped in frozen-etched preparations. Frozen-etched membranes differ in the size and distribution of the surface particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1972.tb03502.x
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  • 4
    Electronic Resource
    Electronic Resource
    Preliminary Observations on the Fine Structure of the Pansporoblast of Thelohania bracteata (Strickland, 1913) (Microsporida, Nosematidae) as Revealed by Freeze-Etching Electron Microscopy (1971)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 18 (1971), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. The ultrastructure of a microsporidan pansporoblast was observed with freeze-etching electron microscopy. The cross-fractured face of ovoid mature spores, with the upper part of the spore coat fractured off, revealed the spore membrane; the convex face had many small depressions and the concave face bore fine particles. In cross-section the spore-coat was highly laminated and about 0.5 μ in diameter.In the cytoplasm of the pansporoblast, fluid-filled and finger-print-life profiles of vesicles were observed. The vesicles were approximately 180 nm in diameter and laminated, each lamella being about 15–18 nm thick. In addition to these vesicles, a population of elevations, each with an average diameter of 40 nm, was evenly distributed in the pansporoblast among the spores. No other cytoplasmic organelles were observed within the pansporoblast. The pansporoblast wall was about 15–19 nm thick with particles 15–18 nm in diameter on its outer surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1971.tb03380.x
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  • 5
    Electronic Resource
    Electronic Resource
    An autoradiographic and ultrastructural study of glycogen metabolism and function in the adult fat body of a black-fly during oögenesis (1972)
    Springer
    Entomologia experimentalis et applicata 15 (1972), S. 265-273 
    Details
    ISSN: 1570-7458
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Wie im Elektronenmikroskop zu sehen ist, führen einen Tag alte Weibchen der autogenen, nordamerikanischen Kriebelmücke, Simulium vittatum Zett., in den Zellen des Fettkörpers reichlich Glykogen. Obwohl der Glykogengehalt während der nächsten zwei Tage der Oogenese rasch abnimmt, behält der Fettkörper unvermindert die Fähigkeit zur Glykogensynthese, wie der rasche Einbau von 14C-Glukose in vivo beweist. Bei Zugabe von Trägerglukose wurde mehr 14C-Glukose als ohne diese eingebaut. Jedoch war der Prozentsatz diastaseresistenter Partikel höher, wenn 14C-Glukose ohne Carrier injiziert wurde, wie autoradiographisch zu erkennen war. Die Häufigkeit dieser diastaseresistenten Partikel und das in den Golgi-Bläschen eingeschlossene elektronendichte Material sowie die zahlreichen Golgi-Komplexe in enger Nachbarschaft der “Glykogen-Region” und das wohlentwickelte endoplasmatische Retikulum lassen vermuten, daß Glykogen in den Fettkörperzellen das Kohlenwasserstoff-Reservoir für die Glykoprotein-Synthese und-Lieferung darstellt. Die ausschließliche Verbreitung von Mitochondrien in der “Glykogen-Region”, welche ebenfalls eng mit dem endoplasmatischen Retikulum verbunden ist, dürfte darauf hinweisen, daß Glykogen außerdem die endogene Energiequelle für den Stoffwechsel in den Fettkörperzellen darstellt.
    Notes: Abstract Glycogen was abundant in fat-body cells of 1-day-old autogenous black-flies (Simulium vittatum Zett.) as seen by electron-microscopy, and decreased during the next 2 days. However, the ability of the fat body to synthesize glycogen remained undiminished. More C14-glucose was incorporated in vivo with added carrier glucose than without. The percentage of “diastase-resistant” particles, as seen by autoradiography, was higher when C14-glucose was injected without the carrier. Along with the abundance of diastase-resistant radioactive particles, the dense material enclosed in the Golgi vesicles, plus the well-developed endoplasmic reticulum and numerous Golgi complexes, suggested that glycogen in the fat-body cell provides carbohydrates for glycoprotein synthesis and export, as well as for an endogenous energy source.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428291
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  • 6
    Electronic Resource
    Electronic Resource
    In vitro activity of 15-azasterol (A25822B) against chalkbrood pathogen Ascosphaera apis in the honey bee (1991)
    Springer
    Mycopathologia 115 (1991), S. 175-184 
    Details
    ISSN: 1573-0832
    Keywords: Apis mellifera L. ; Ascosphaera apis ; honey bees ; chalkbrood ; 15-azasterol ; A25822B ; ultrastructure ; lipid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The antifungal agent 15-azasterol A25822B was examined for effects on the growth and development of Ascosphaera apis. The minimum inhibition concentration (MIC) of azasterol against A. apis was 1 μm. Growth and development of A. apis was completely controlled at this concentration. At a concentration of 0.01 μm growth of A. apis was retarded and although sporocysts were formed developing spores were not be able to reach maturation. A major effect of azasterol at this low concentration was the accumulation of lipid in the hyphae, sporocysts and immature spores. In addition it caused a conformational change in mitochondria and damage to the spore membrane structure. On the basis of these results, further investigations of azasterol for the treatment of chalkbrood disease in the honey bee are warranted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00462222
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  • 7
    Electronic Resource
    Electronic Resource
    Fine structure of the sporocysts of Ascosphaera apis during development as revealed by the scanning electron microscope (1987)
    Springer
    Mycopathologia 100 (1987), S. 155-158 
    Details
    ISSN: 1573-0832
    Keywords: Ascosphaera apis ; sporocysts ; spore ball ; Chalkbrood disease ; honey bee
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The fine morphology of the sporocysts of Ascosphaera apis (Maassen ex Claussen) Olive & Spiltoir, an entomopathogenic fungus of the immature honey bee has been studied using the scanning electron microscope. During the third day of mycelial growth in the culture medium, numerous short, branched hyphae were formed. The tip of the branch-hypha gradually expanded to form immature sporocysts. The immature sporocysts contained a large number of globules of varying sizes. The walls of the immature sporocysts were finely wrinkled, becoming smooth as the sporocyst matured. Both exterior and interior surfaces of the sporocyst wall possessed numerous papillae. Some globules in the developing sporocyst began to form immature spores which aggregated to form spore balls. The fully formed spore balls were not enveloped by a membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00437041
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of itraconazole on the sporocysts wall of the entomopathogenic fungi Ascosphaera apis as revealed by the scanning electron microscope (1988)
    Springer
    Mycopathologia 103 (1988), S. 75-80 
    Details
    ISSN: 1573-0832
    Keywords: Ascosphaera apis ; Chalkbrood disease ; honey bee ; itraconazole ; sporocysts wall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The young sporocysts had a wrinkled sporocyst wall, numerous papillae on the wall surface and the wall was granular and porous. In the itraconazole-treated culture, the walls of the young sporocysts were also wrinkled, but the characteristic papillae were replaced by larger lumps which were densely packed and coated the entire surface of the sporocyst wall. The mature sporocysts walls were smooth and possessed numerous papillae. In the itraconazole-treated culture, the walls of mature sporocysts walls were also smooth but possessed densely packed larger lumps instead of papillae. At higher magnification, each of the lumps were found to consist of numerous globules. No pores were observed as they were in the normal sporocyst wall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00441261
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  • 9
    Electronic Resource
    Electronic Resource
    Ultrastructural changes in the spore and mycelia of Ascosphaera apis after treatment with benomyl (Benlate 50 W) (1991)
    Springer
    Mycopathologia 116 (1991), S. 23-28 
    Details
    ISSN: 1573-0832
    Keywords: Ascosphaera apis ; hyphae spore ; honey bees ; chalkbrood disease ; Benomyl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In Ascosphaera apis, after 8 days growth in darkness at 28° C, numerous sporocysts were observed, within which mature spores were seen aggregated into a spore ball. The mature spore of A. apis had a thick spore wall with an electron-opaque outer layer, a spore membrane with many depressions, and sporoplasm containing numerous ribosomes and mitochondria. In the cytoplasm of the mycelium, mitochondria with well-defined cristae and numerous ribosomes were observed. At a concentration of 1 μg/ml of culture medium, benomyl appeared to inhibit colony growth of A. apis, but some sporocysts containing deformed spores were found. Deformed spores possessed a thick spore wall with a grainy matrix, and depressions were no longer detected in the spore membrane. Ribosomes were lacking in the sporoplasm and mitochondria appeared degenerate. The mycelium from the treated culture contained mitochondria with an electron-lucid matrix and no well defined cristae, while ribosomes were completely depleted. The significance of these observations in relation to the use of benomyl to control chalkbrood disease in the honey bee is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00436086
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  • 10
    Electronic Resource
    Electronic Resource
    Nonlinear stability and instability of transonic flows through a nozzle (1982)
    Springer
    Communications in mathematical physics 83 (1982), S. 243-260 
    Details
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract We study transonic flows along a nozzle based on a one-dimensional model. It is shown that flows along the expanding portion of the nozzle are stable. On the other hand, flows with standing shock waves along a contracting duct are dynamically unstable. This was conjectured by the author based on the study of noninteracting wave patterns. The author had shown earlier that supersonic and subsonic flows along a duct with various cross sections are stable. Basic to our analysis are estimates showing that shock waves tend to decelerate along an expanding duct and accelerate along a contracting duct.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01976043
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