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  • Chemistry  (6)
  • Electron microscopy  (3)
  • House fly  (3)
  • 1
    Digitale Medien
    Digitale Medien
    Effect of dietary cholesterol on the pattern of osmium deposition in the symbiote-containing cells of the pea aphid (1977)
    Springer
    Cell & tissue research 176 (1977), S. 191-203 
    Details
    ISSN: 1432-0878
    Schlagwort(e): OsO4 ; Cholesterol ; Symbiotes ; Aphids ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Pea aphids left for 48 h in unbuffered osmium tetroxide show heavy staining of many organelles in the symbiote-containing cells (mycetocytes and sheath), embryos and oenocytes very similar to that characteristic of mammalian sterol-synthesizing cells. However, the staining of the pea-aphid cells is, to a large extent, dependent on the presence of cholesterol benzoate, or free cholesterol, in the aphid's diet. In aphids cultured in vitro with 3H mevalonate in the presence of added cholesterol, the incorporation of label into the cholesterol and lanosterol fractions is significantly reduced. If the dietary cholesterol effects a similar inhibition in vivo, the cholesterol-dependent osmium staining could be due to precursors(s) of cholesterol accumulating in the intracellular sites described. There is also osmium staining of large (normally electron-transparent) vacuoles in mycetocytes, gut and fat body, irrespective of dietary cholesterol.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00229462
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  • 2
    Digitale Medien
    Digitale Medien
    Membrane specializations in the peripheral retina of the housefly Musca domestica L. (1979)
    Springer
    Cell & tissue research 198 (1979), S. 501-520 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Peripheral retina ; Transmission electron microscopy ; House fly ; Membrane specializations and pigment cells ; Photoreceptor cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Membrane specializations of the peripheral retina of the housefly (Musca domestica) are revealed in thin sections and freeze fracture/etch replicas. Septate junctions are abundant in corner areas of the pseudocone enclosure bonding: between homologous corneal pigment cells (CPC); between homologous large pigment cells (LPC); between CPC-LPC; between Semper cells (SC); between SC-CPC. Spot desmosomes are present between Semper cells. It is likely that septate junctions function as strengthening adhesions in this area. A new membrane specialization similar to a continuous junction was observed between retinular cells of the same or adjacent ommatidium. This junction has indistinct septa in the 115Å intermembrane cleft and is intermittent in character. When this junction is absent, the apposed cells gape apart. In freeze fracture studies, this junction is characterized by bridges composed of fused membrane particles and randomly arranged particles on the P face, and non-corresponding grooves on the E face. The ridges are elongate and roughly parallel and sometimes they form enclosures. Mitochondria line up along these junctions, often within 90Å of the unit membrane. This membrane specialization has characteristics of tight and continuous junctions. In line with previous findings, we suggest that this junction assists in retinular cell orientation, possibly in enforcing the ommatidial twist and in maintaining localized ionic concentration gradients between retinular cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234194
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  • 3
    Digitale Medien
    Digitale Medien
    Pulsed discharge photoionization detector: Application to analysis of chloro alkanes/alkenes (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 85-90 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A windowless pulsed discharge photoionization detector (PDPID) is described which uses the emission spectra from the discharge in helium and Ar/Kr doped helium. The emission from helium is a continuum ranging from 13.5-17.7 eV which ionizes all compounds except neon. The emission from 5.4% Ar/He ranges from 9.3-11.8 eV and ionizes most organic compounds and many inorganic compounds. The emission from 1.36% Kr/He consists principally of the resonance lines at 10.6 and 10.1 eV. These PDPIDs are used to analyze a 12 component mixture containing principally chloro alkane/alkene. The relative responses of the PDPID combined with the relative retention time can be used to qualitatively identify the chloro compounds.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190205
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  • 4
    Digitale Medien
    Digitale Medien
    The large pigment cell of the compound eye of the house fly Musca domestica (1976)
    Springer
    Cell & tissue research 170 (1976), S. 77-88 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Compound eye ; House fly ; Large pigment cells ; Corneal pigment cells ; High voltage and conventional electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fine structure and cellular associations of the large pigment cells (LPC's) of the compound eye of the house fly were studied with high voltage and conventional electron microscopy. Depending on the sector of the compound eye, the facets are either rectangular or hexagonal. The underside of each facet has indentations exactly aligned with those on top into which inserts an angulated sleeve of LPC's. Under the rectangular lens facet 6 or 8 small compact (in cross section) LPC's join four elongate LPC's. Clusters of compact cells alternate in this ring with elongate ones. Compact cells compress together and become quadrangular (in cross section) several microns below their insertion into the lens and form “building block” corners while elongate cells form “side rails” for the rectangular type of distal pseudocone enclosure. Beneath hexagonal facets all LPC's are rather elongate with out corner cells. In both facet types LPC's enclose the pseudocone for a longitudinal distance of 4 μm and then are displaced as bordering cells by a sleeve of two corneal pigment cells (CPC's), each of which encloses half of the proximal pseudocone. For the following 6 μm of longitudinal distance these concentric sleeves of CPC's and LPC's form a double layer around the pseudocone. At about 10 μm below lens base the two sleeves separate; LPC's become attenuated and extend cable-like to the basement membrane and CPC's enclose the proximal pseudocone, Semper cells and distal retinula. The junction between lens and LPC's has critical structural value in that (1) this is the sole anchorage to the lens by the lengthy remainder of the ommatidium, and (2) LPC's enclose the semiliquid pseudocone in the most distal portion of the pseudocone. In addition to vertical support, the LPC's send out numerous lateral processes that make structural contact among themselves, with the corneal pigment cells and the photoreceptor cells. The structural features of this array are discussed relative to possible physiological roles.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220111
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  • 5
    Digitale Medien
    Digitale Medien
    Effects of antibiotics on intracellular symbiotes in the pea aphid, Acyrthosiphon pisum (1974)
    Springer
    Cell & tissue research 148 (1974), S. 287-300 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Symbiotes ; Aphids ; Antibiotics ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effects of penicillin and chlortetracyline HCl on the fine structure of the intracellular symbiotes of the pea aphid were studied in an attempt to remove the symbiote population. High penicillin concentrations, 1% and 0.1%, caused symbiote breakdown but were toxic and/or repellent to the aphids; at 0.1% specific effects were observed on the symbiotes' cell walls. After the use of 0.01% penicillin in the aphid diet, the symbiotes had abnormal cell walls and were abnormally dilated; however, symbiote division and transmission from one aphid generation to the next seemed unaffected and the aphids appeared normal. Aphids fed 0.1% chlortetracycline failed to reproduce. After 7 days, their symbiotes were found to break down at a high rate but aphid mitochondria were also adversely affected at this stage. Following 0.002% chlortetracycline, the aphids produced aposymbiotic progeny with apparently normal mitochondrial populations; these larvae failed to develop.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00224257
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  • 6
    Digitale Medien
    Digitale Medien
    High voltage electron microscopy of the optic neuropile of the housefly, Musca domestica (1976)
    Springer
    Cell & tissue research 167 (1976), S. 537-545 
    Details
    ISSN: 1432-0878
    Schlagwort(e): House fly ; Retinular axons ; Interneurons ; Lamina ganglionaris ; High voltage electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Synaptic cartridges of the first optic neuropile (lamina ganglionaris) of the housefly were examined by high voltage electron microscopy (HVEM). Stereo pairs (from thick, i.e., 0.25 μm, sections viewed at 1,000 kV) provided a three dimensional representation of cartridge neurons and clearly revealed the lateral spread, bifurcation and some functional associations of Type I (L1, L2) monopolar interneurons. Slightly proximal to cartridge neck level, pairs of retinular (R) axons made contact with each other and it appeared that R processes projected through the cleft between the Type I interneurons. No junctional modifications were seen between contiguous R axon terminals. The speculation was made that functional contact might exist between neighboring R axons prior to their extensive synapses with principal first order interneurons. Such alleged coupling between R axons would account for several electrophysiological findings from other laboratories. Modifications in EM technique applicable for HVEM were detailed. The value of obtaining thick serial sections and the use of the HVEM in expediting three dimensional reconstructions of neuropile were demonstrated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00215183
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  • 7
    Digitale Medien
    Digitale Medien
    Ultrastructure of pea aphid mycetocytes: Evidence for symbiote secretion (1975)
    Springer
    Cell & tissue research 159 (1975), S. 351-367 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Symbiotes ; Aphids ; Vesicles ; Organelles ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A detailed investigation into the ultrastructure of the pea aphid mycetocytes and their contained symbiotes and organelles was carried out with the transmission electron microscope. The most striking observation was the presence of small vesicles in the space between the primary symbiote cell wall and membrane envelope (outer membrane space). The vesicles appear to form by a budding process at the outer cell wall layer. Subsequently, the vesicles, we suggest, may move out into the mycetocyte cytoplasm via a similar budding of the membrane envelope. The Golgi apparatus was found to be an important structural component of the primary mycetocyte; it is continuous with the rough endoplasmic reticulum and the latter, in turn, appears to be closely connected to the primary symbiote membrane envelope. This may be of functional significance. A number of other organelles not previously described in mycetocytes were found, including transparent vacuoles, granular bodies, multivesicular bodies and microfilaments. The chemical composition of the various vesicles and organelles is unknown at present.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00221782
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  • 8
    Digitale Medien
    Digitale Medien
    Effect of non-complementary nucleotides on the rate of helix formation: Kinetics of formation of poly (I)·poly (C,I) and poly (I)·poly (C,U) complexes (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 1613-1620 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Apparent second-order rate constants for complex formation between poly (I) and poly (C) and copolymers of C containing non-complementary I or U residues have been determined spectrophotometrically. The rate constants decrease as the concentration of either I or U in the C strands increases-the effect seems insensitive to the species of residue involved, when differences in the thermal stabilities of the poly (I) poly (C,I) and poly (I). poly (C,U) complexes are taken into account. These results suggest that low concentrations of relatively stable defects can alter the apparent kinetic “complexity” of polynucleotides as determined by hybridization methods (C0t analysis).
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1972.360110808
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  • 9
    Digitale Medien
    Digitale Medien
    Studies on Antifungal Agents. Part 22. 3-aryl-5-[(aryloxy)alkyl]-3-[(1H-imidazol-1-yl)methyl]-2-methylisoxazolidines and related derivatives (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 718-732 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The synthesis and antifungal activity of a novel series of 3-aryl-5-[(aryloxy)alkyl]-3-[(1H-imidazol-1-yl)-methyl]-2-methylisoxazolidines and related compounds, are discussed. The synthesis of the title compounds was accomplished via a 1,3-dipolar cycloaddition of α-substituted ketonitrones with l-alkenyl phenyl ethers (Scheme 2 and 3). The compounds were evaluated for in vitro antifungal activity in solid agar cultures against a broad variety of yeast and systemic mycoses and dermatophytes. While antifungal activity was evident throughout the series, in general, derivatives having halogen atom(s) in either or both aryl rings demonstrated the highest potency, especially against Trichophyton rubrum and Candida albicans. The dichloro analog 20 (PR 967-248) was found to possess the most useful activity. Its minimum inhibitory concentration (MIC) values ranged between 0.2 and 2.0 μg/ml, as compared to 0.2-20.0 μg/ml for the standard drug ketoconazole (4).
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19880710406
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  • 10
    Digitale Medien
    Digitale Medien
    Studies on Antifungal Agents. Part 25. 1-[(3,5-Bisaryl-2-methylisoxazolidin-3-yl)methyl]-1H-1,2,4-triazoles (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1622-1629 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The synthesis and antifungal activity of a novel series of 1-[(3,5-bisaryl-2-methylisoxazolidin-3-yl)methyl]-1H-1,2,4-triazoles 6 and 7 (i.e. 8-19) are discussed. The preparation of 8-19 was straightforward and highlighted by a regiospecific 1,3-dipolar cycloaddition of α-substituted (E)-ketonitrones 4 with appropriate atyrene derivatives 5 that led to a cis/trans-diastereoisomeric mixture of the corresponding triazoles (Scheme). The title compounds were evaluated for in vitro antifungal activity in solid agar cultures against a broad array of yeast and systemic mycoses and dermatophytes. The in vivo activity was determined in an immune-compromised mouse model of systemic candidiasis. While the in vitro activity was evident throughout the series, it was moderate in potency. However, some of the triazole derivatives demonstrated a potent in vivo activity comparable to that of the standard drug ketoconazole. Analogue 12 (PR 988-399) emerged as the best overall compound demonstrating potent antifungal activity in both in vitro and in vivo assays.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19880710706
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