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  • 1
    Digitale Medien
    Digitale Medien
    Heterogeneity of the calcium-induced permeability transition in isolated non-synaptic brain mitochondria (2002)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 83 (2002), S. 0 
    Details
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Calcium overload of neural cell mitochondria plays a key role in excitotoxic and ischemic brain injury. This study tested the hypothesis that brain mitochondria consist of subpopulations with differential sensitivity to calcium-induced inner membrane permeability transition, and that this sensitivity is greatly reduced by physiological levels of adenine nucleotides. Isolated non-synaptosomal rat brain mitochondria were incubated in a potassium-based medium in the absence or presence of ATP or ADP. Measurements were made of medium and intramitochondrial free calcium, light scattering, mitochondrial ultrastructure, and the elemental composition of electron-opaque deposits within mitochondria treated with calcium. In the absence of adenine nucleotides, calcium induced a partial decrease in light scattering, accompanied by three distinct ultrastructural morphologies, including large-amplitude swelling, matrix vacuolization and a normal appearance. In the presence of ATP or ADP the mitochondrial calcium uptake capacity was greatly enhanced and calcium induced an increase rather than a decrease in mitochondrial light scattering. Approximately 10% of the mitochondria appeared damaged and the rest contained electron-dense precipitates that contained calcium, as determined by electron-energy loss spectroscopy. These results indicate that brain mitochondria are heterogeneous in their response to calcium. In the absence of adenine nucleotides, approximately 20% of the mitochondrial population exhibit morphological alterations consistent with activation of the permeability transition, but less than 10% exhibit evidence of osmotic swelling and membrane disruption in the presence of ATP or ADP.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1471-4159.2002.01238.x
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  • 2
    Digitale Medien
    Digitale Medien
    Myelin-like sheaths in copepod axons (1999)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 398 (1999), S. 571-571 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Copepods, the small planktonic crustaceans that are the most abundant metazoans in the oceans, are so successful partly because they have an escape response that accelerates them to 200 body lengths per second within milliseconds. We find that nerve fibres of many copepods seem to be designed ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/19212
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  • 3
    Digitale Medien
    Digitale Medien
    Methane oxidation by an extremely acidophilic bacterium of the phylum Verrucomicrobia (2007)
    [s.l.] : Nature Publishing Group
    Nature 450 (2007), S. 879-882 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Aerobic methanotrophic bacteria consume methane as it diffuses away from methanogenic zones of soil and sediment. They act as a biofilter to reduce methane emissions to the atmosphere, and they are therefore targets in strategies to combat global climate change. No cultured methanotroph grows ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/nature06411
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  • 4
    Digitale Medien
    Digitale Medien
    Ultrastructural changes associated with K+-evoked peptide secretion from a neurohemal organ of the crab, Cardisoma carnifex (1985)
    Springer
    Cell & tissue research 242 (1985), S. 67-73 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Neurosecretion ; Sinus gland ; Ultrastructure ; Potassium stimulation ; Crustacea ; Hormone release
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Electron-microscopic comparison of K+-stimulated and unstimulated crab sinus glands reveals significant differences in neurosecretory terminal morphology. Sinus glands exposed to elevated K+ saline for increasing periods of time show increasing numbers of exocytotic release profiles, vacuoles, and multilamellate bodies, and a decrease in the number of microvesicles within 10 μm of release sites. These morphological changes are well correlated with secretion of red-pigment-concentrating hormone, as determined by bioassay of perfusate from the individual preparations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00225564
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  • 5
    Digitale Medien
    Digitale Medien
    Ultrastructural changes in isolated peptidergic nerve terminals induced by digitonin permeabilization and K+ stimulation in the sinus gland of the crab, Cardisoma carnifex (1986)
    Springer
    Cell & tissue research 246 (1986), S. 365-371 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Neurosecretion ; Sinus gland ; Isolated nerve endings ; Potassium stimulation ; Digitonin permeabilization ; Cardisoma carnifex
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The preparation of isolated peptidergic nerve terminals from the sinus gland (a neurohemal organ) of the crab (Cardisoma carnifex) is described. In this species the nerve endings can have diameters up to 30 μm. They release neurosecretory material as judged by the decrease in the volumetric density of granules upon depolarization with potassium. Similar results were obtained after permeabilization of the nerve terminals with digitonin, but only in the presence of micromolar concentrations of calcium. This preparation should prove useful in correlating electrical events with other cellular processes involved in stimulus-secretion coupling.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00215899
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  • 6
    Digitale Medien
    Digitale Medien
    Developmental changes in structure and polypeptide profile of the androgenic gland of the freshwater prawn Macrobrachium rosenbergii (2000)
    Springer
    Aquaculture international 8 (2000), S. 327-334 
    Details
    ISSN: 1573-143X
    Schlagwort(e): androgenic gland ; androgenic hormone ; freshwater prawn ; light and transmission electron microscopy ; (Macrobrachium rosenbergii) ; male morphotypes ; sex-differentiation sodium dodecyl sulfate polyacrylamide gel electrophoresis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Although the mechanism of sex-differentiation in crustaceans has yet to be defined, the androgenic gland (AG) is thought to be the exclusive organ that produces the androgenic hormone (AH) which induces male sexual development. This paper presents results of light and transmission electron microscopy and total protein analysis of androgenic glands from three male morphotypes (orange-claw, orange-blue-claw and blue-claw) of the freshwater prawn, Macrobrachium rosenbergii. Highest protein content (76 µg//AG) was found in the blue-claw morphotype as compared to the orange-blue-claw (45 µg/AG) and the orange-claw morphotype (19 µg/AG). Sodiumdodecyl sulfate polyacrylamide gel electrophoresis (SDS-page) analysis of the cell free extract of the AG from the three morphotypes revealed four polypeptides (∼16, ∼18, ∼23 and ∼26 Kd) which quantitatively increase from the sexually immature orange-claw to the sexually mature blue-claw morphotype. The 16 and 18 Kd polypeptides could be the AHs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009205027360
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  • 7
    Digitale Medien
    Digitale Medien
    Ultrastructural study of the sinus gland of the crab, Cardisoma carnifex (1981)
    Springer
    Cell & tissue research 220 (1981), S. 293-312 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Neurosecretion ; Sinus gland ; Ultrastructure ; Crustacea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The sinus gland of Cardisoma carnifex was examined by light and transmission electron microscopy. This neurohemal organ is composed primarily of enlarged, branching axon terminals with numerous finger-like projections, which act as storage and release sites for neurohormones that are assumed to be contained in membrane-bound, electron-dense neurosecretory granules. Also present in the sinus gland are glial cells with cytoplasmic processes which form elaborate wrappings around neurosecretory terminals, and an acellular fibrillar lining of the branching blood sinus. Six types of neurosecretory terminals are identified on the basis of granule size, granule density, and density of the axoplasmic matrix. Images supporting the hypothesis of release of neurosecretory material by exocytosis from terminals abutting the blood sinus lining are found. Large multilamellate bodies appear in terminals depleted of neurosecretory granules and may be involved in the recycling of granule membrane.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00210510
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