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2001 (1)
1982 (2)
1980 (1)
1Author    Helga Sittertz-BhatkarRequires cookie*
 Title    Oral Cleansing in Spiders is Gland Mediated!  
 Abstract    Histochemical and micromorphological investigations of the gnathocoxal gland in spiders brought out its uniquely adaptive cleansing function. The prey particulates, caught in the oral mi­ crostructures, are bound with mucopolysaccharides or glyco-muco-proteins from the glandular se­ cretions in Araneus and Theridion species into a bolus, and are expelled following each food up­ take. 
  Reference    Z. Naturforsch. 35c, 669—673 (1980); received October 20 1979 
  Published    1980 
  Keywords    Oral Cleansing, Spiders, Gnathocoxal Gland, Histochemistry, Micromorphological Investigations 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0669.pdf 
 Identifier    ZNC-1980-35c-0669 
 Volume    35 
2Author    Walter Feucht3, Jürgen PolsterRequires cookie*
 Title    Nuclei of Plants as a Sink for Flavanols  
 Abstract    Onion cepa (L.) and Tsuga canadensis (L.) Carr, were investigated histochemically on the association of flava­ nols to nuclei. The young roots of Onion cepa are totally devoid of flavanol structures. Therefore, the excised roots tips were directly incubated into different solutions of flavanols. A fter 3 h of incubation a flavanol binding on the nuclei was recognizable, as seen by a yellowish-brown tanning reaction. Still to ensure the presence of flavanols on the nuclei, subsequent staining with the p-dimethylaminocinnamaldehyde reagent (DM ACA) re­ sulted in an intense blue colouration. Tsuga canadensis has significant amounts of vacuolar flavanol deposits in all parts of the tree as indicated by the DM ACA rea­ gent. It is obvious that also the nuclei were associated strongly with flavanols which can be dem onstrated par­ ticularly elegant in the cells of the seed wings by histo-chemical methods. However, the mode of flavanol re­ lease from the original deposits is not yet clear. 
  Reference    Z. Naturforsch. 56c, 479—481 (2001); received November 21 2000/March 12 2001 
  Published    2001 
  Keywords    Flavanols, Nucleus, Histochemistry, DM ACA Reagent 
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 TEI-XML for    default:Reihe_C/56/ZNC-2001-56c-0479_n.pdf 
 Identifier    ZNC-2001-56c-0479_n 
 Volume    56 
3Author    R. Meyer, M. Schmitz, W. Stockem, H. G. HaasRequires cookie*
 Title    Localization of Ca2+ at the Plasma Membrane of Bullfrog Myocardial Cells  
 Abstract    Cellular distribution and localization of Ca2+ in bullfrog myocardial cells was investigated on the light and electron microscopical level using different preparation procedures. Fixation and dehydration in glutaraldehyde and ethanol solutions containing increased amounts of Ca2+ (5-25 m M) cause the formation of numerous electron-dense deposits at the external face of the sarcolemma. X-ray microanalysis demonstrates that the deposits are mainly composed of calcium. Similar results were obtained in cryopreparations by quick-freezing of fresh myocardial tissue. Granules with a diameter of 16.6 nm, which clearly exceed all other cell constituents in contrast, are found at the entire myocardial cell surface. Besides an increased amount of calcium the granules contain potassium and phosphorus. Fluorescence microscopy on single cells obtained from bullfrog atrium by treatment with digestive enzymes and stained with chlorotetra-cycline (CTC) as a fluorescent probe for membrane-bound Ca2+ clearly support the observations made on the fine structural level. A strong fluorescence signal depending on the CTC-and Ca2+-concentration of the incubation medium is observed at the sarcolemma and can be inhibited by addition of La3+. The results of the present investigation suggest that the surface coat of the sarcolemma of myocardial cells represents an important compartment for accumulation and release of external Ca2+. The external lamina which partly covers the surface of myocardial cells seems not to be involved in the Ca2+ exchange. 
  Reference    Z. Naturforsch. 37c, 1180—1190 (1982); received August 12 1982 
  Published    1982 
  Keywords    Bullfrog Myocardial Sarcolemma, Histochemistry, Cryofixation, X-ray Microanalysis, Ca2+-Binding Sites 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-1180.pdf 
 Identifier    ZNC-1982-37c-1180 
 Volume    37 
4Author    R. Meyer, W. Stockem, M. Schmitz, H. G. HaasRequires cookie*
 Title    Histochemical Demonstration of an ATP-Dependent Ca2+-Pump in Bullfrog Myocardial Cells  
 Abstract    In the present investigation different finestructural and histochem ical procedures were employed to demonstrate normal morphology and Ca2+-transport m echanism in bullfrog atrial myocardium. For normal morphology specim ens were fixed in 1% 0 s 0 4, 2.5% glutaraldehyde or liquid propane at -1 8 5 ° C before they were prepared for conventional em bedding and freeze-etching, respectively. Special interest was focussed on the caveolae system, which is com posed o f single, spherical membrane invaginations (diam eter, 85 nm), randomly distributed at the entire cell periphery. The caveolae enlarge the cell surface by 24.5% and occupy 8.5% o f the cellular volume. The caveolae m embrane contains a few intram em braneous particles with a diam eter o f 8.4 nm comparable to the size o f ATPases as found in other cells. For histochemistry the specimens were first stabilized by treatment with 50% glycerol, 0.025% glutaraldehyde or 0.15% formaldehyde and then incubated in a m edium containing 4 mM CaCl2, 4 mM EGTA, 5 mM MgCl2, 5 mM K 2C?0 4, 5 mM A TP and 20 mM histidine at pH 7.0. This incuba­ tion always succeeded in the formation o f electron-dense deposits with elliptical shape, m ea­ suring 1 0 0 -2 0 0 nm in length and 1 0 -3 0 nm in diam eter. According to X-ray spectra they deliver a characteristic calcium-peak and can be found within two different cellular compartments: in small invaginations o f the sarcolemma, i. e. the caveolae-system , and in the intrafibrillar sarcoplasmic reticulum. The elliptical deposits can be clearly distinguished from round electron-dense granules measuring 16 nm in diameter, which are located within random ly distributed small vesicles and composed o f potassium and phosphate. Contrary to the elliptical deposits the round granules are also present in controls and seem to be identical with the so-called atrial granules. In comparison to observations obtained with the sam e m ethod in other muscular systems and derived from various control experim ents the results o f this study favour the existence o f an ATP-dependent Ca2+-pumping mechanism in frog atrial m uscle bound to both, the sarco­ plasmic reticulum and the caveolae system. 
  Reference    Z. Naturforsch. 37c, 489 (1982); received February 5 1982 
  Published    1982 
  Keywords    Bullfrog Myocardium, Histochemistry, Freeze-Etching, C aveolae-System, C a2+-Pum p 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0489.pdf 
 Identifier    ZNC-1982-37c-0489 
 Volume    37