Elektronenmikroskopische Untersuchungen zur funktionellen Morphologie des Ionentransportes in der Salzdr�se von Larus argentatus

Komnick, Hans; Komnick, Ute

doi:10.1007/bf00350475

Cited by 112 publications

(35 citation statements)

References 20 publications

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“…By introduction of the ultracytochemical pyroantimonate technique 12 it was possible to study calcium in its subcellular sphere of action. 13 The method was shown to precipitate calcium in a number of tissues with secretory activity.…”

mentioning

confidence: 99%

Ultracytochemical Calcium Distribution in B Cells in Relation to Biphasic Glucose-stimulated Insulin Release by the Perfused Rat Pancreas

Klöppel

1979

Diabetes

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Calcium distribution in B cells of the isolated perfused rat pancreas was examined by the pyroantimonate precipitation technique in relation to the insulin secretory pattern of the perfused pancreas in response to 3 mM or 20 mM D-glucose or 20 mM D-glucose in calcium-depleted ethylene glycol tetra-acetic acid (EGTA) medium. Perfusion fixation after various time intervals from 3 to 30 min allowed appropriate relation to secretory phases. Qualitative and quantitative evaluation of the precipitation patterns revealed a significant increase in cell membrane associated percipitates after 3--5 min of perfusion with 20 mM glucose compared with the results after perfusion with 3 mM glucose. After 10--30 min of perfusion with 20 mM glucose there was an additional significant increase in precipitates located in the cytoplasm and the halos of the secretory granules. Perfusion with 20 mM glucose in calcium-deprived EGTA medium strongly reduced the number of precipitates within the B cells. The results suggest that cell membrane associated calcium may be involved in exocytosis, and by its sudden increase may trigger the first phase of insulin secretion. The calcium stores in the cytoplasm and the granules may be of importance for long-term regulation of insulin release.

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mentioning

confidence: 99%

Ultracytochemical Calcium Distribution in B Cells in Relation to Biphasic Glucose-stimulated Insulin Release by the Perfused Rat Pancreas

Klöppel

1979

Diabetes

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“…In order to detect intracellular Ca, the fiber bundles were treated in a relaxed state with unbuffered 1% OsO4 containing 2% potassium pyroantimonate, K [Sb(OH)6] ( KOMNICK and KOMNICK, 1963). The pH of the solution was ultimately adjusted to about 6.0, 6.6 or 7.2 with 0.01N acetic acid or KOH.…”

Section: Methodsmentioning

confidence: 99%

“…Since KOMNICK and KOMNICK (1963) first demonstrated that K-pyroantimonate formed electron opaque precipitate with tissue sodium, this technique has been widely used to detect certain cations such as Na, Ca and Mg in the tissue; control experiments are necessary because pyroantimonate is known to combine with several in Mytilus Smooth Muscle 253 cations (KOMNICK and KOMNICK, 1963;BULGER, 1969;TORACK and LAVALLE, 1970;SHIINA et al, 1970;TANDLER et al, 1970;KIERSZENBAUM et al, 1971;KLEIN et al, 1972;GARFIELD et al, 1972). LEGATO and LANGER (1969) and YAROM and MEIRI (1971 have suggested the possibility that the precipitate with PAO was due to Ca-pyroanti monate in heart and skeletal muscles, respectively.…”

Section: Identification Of the Precipitatementioning

confidence: 99%

Sarcoplasmic Reticulum and Intracellular Calcium Localization at Rest and during Contraction in <i>Mytilus</i> Smooth Muscle

Atsumi

1978

Arch. Histol. Jap., Arch. Histol. Jpn

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“…In order to obtain optimal preservation of biological samples, including ion content, several cytochemical reactions have been tried in the past (Borges et al, 1977;Komnick and Komnick, 1963;Simson andSpicer, 1975, Mata et al, 1987). It is well known that chemical fixation interferes with diffusion properties of the cell membranes and causes shrinkage and loss of diffusible ions (Studer et al, 1989).…”

Section: Introductionmentioning

confidence: 99%

Contribution of cryofixation and freeze‐substitution to analytical microscopy: A study of Tritrichomonas foetus hydrogenosomes

Ribeiro

Benchimol

Farina

2001

Microscopy Res & Technique

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The hydrogenosome, an organelle that produces molecular hydrogen and ATP from the oxidation of pyruvate or malate under anaerobic conditions, presents some characteristics common to mitochondria. It is found in several trichomonad species, protists living in oxygen-poor environments, as well as certain free-living ciliates, rumen ciliates, and some fungi. We performed a comparative microanalytical study (energy dispersive X-ray analysis and electron spectroscopic imaging) of different fixation methods for electron microscopy analyzing hydrogenosomes of the bovine parasite Tritrichomonas foetus. The study included the elemental composition and the mapping of calcium, phosphorus, and oxygen. A preparation of T. foetus cells, based on cryoimmobilization by high-pressure freezing and freeze-substitution, was compared to a second preparation based on chemical fixation followed by dehydration and routine processing. The ultrastructural preservation achieved by the cryotechnique was far superior to the chemical fixation, since it allowed the successful cryoimmobilization of intracellular ion contents. The detection of several cations (Al, Mg, Co, Ca, Fe) by X-ray microanalysis inside the peripheral vesicle of the hydrogenosome was only possible in cryofixed cells. The presence of aluminum and cobalt ion in the hydrogenosomal vesicle was established for the first time. Electron-spectroscopic images of calcium showed that this element, in addition to the vesicle compartment, is present in the hydrogenosome's membrane in varying concentrations, which might reflect changes in the physiology of this organelle.

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Elektronenmikroskopische Untersuchungen zur funktionellen Morphologie des Ionentransportes in der Salzdr�se von Larus argentatus

Cited by 112 publications

References 20 publications

Ultracytochemical Calcium Distribution in B Cells in Relation to Biphasic Glucose-stimulated Insulin Release by the Perfused Rat Pancreas

Ultracytochemical Calcium Distribution in B Cells in Relation to Biphasic Glucose-stimulated Insulin Release by the Perfused Rat Pancreas

Sarcoplasmic Reticulum and Intracellular Calcium Localization at Rest and during Contraction in <i>Mytilus</i> Smooth Muscle

Contribution of cryofixation and freeze‐substitution to analytical microscopy: A study of Tritrichomonas foetus hydrogenosomes

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