Karl Heinz Körtje

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Characteristic calcium signals were analyzed in structures of three cell types of the root cap of cress: statocytes, meristematic cells and secretion cells. Twenty-four hour-old roots were fixed with glutaraldehyde (postfixed with osmiate/potassium bichromate) or with potassium permanganate. No visible precipitates were formed, but calcium signals typical(More)
High-affinity Ca2(+)-ATPase activity in the optic tectum of the brain of cichlid fish was cytochemically localized using cerium ions to precipitate phosphate. Activation of the enzyme with micromolar instead of millimolar calcium concentrations (i.e., physiological cytoplasmic instead of extracellular concentrations) resulted in intracellular localization(More)
Energy-filtering transmission electron microscopy has been applied to the quantification of area fractions of calcium-containing cytochemical reaction products in central nervous tissue and the retina of fish. The method of electron spectroscopic imaging using electrons with an energy loss of 250 eV produces images with a very high, structure-sensitive(More)
On the basis of quantitative disturbances of the swimming behaviour of aquatic vertebrates ("loop-swimming" in fish and frog larvae) following long-term hyper-g-exposure the question was raised whether or not and to what extent changes in the gravitational vector might influence the CNS at the cellular level. Therefore, by means of histological,(More)
Electron microscopy of nervous tissue requires on the one hand nanometre resolution for the analysis of fine structures of nerve cell contacts, for instance synaptic vesicles, synaptic membranes and associated organelles. On the other hand, the visualization of the three-dimensional organization of nervous tissue on the level of dendrites and neurites is(More)
Two different modes of energy-filtering transmission electron microscopy (EFTEM) are often used for element microanalysis: electron energy-loss spectroscopy (EELS) and electron spectroscopic imaging (ESI). A new approach was developed which we call Image-EELS. This procedure was realized with the commercially available standard equipment of the(More)
Four different methods for calcium precipitation are compared in the optic tectum and the inner ear of the cichid fish, Oreochromis mossambicus. Several parameters are investigated concerning their influences on the reaction product. Three procedures (bichromate, fluoride, and oxalate-pyroantimonate) produce fine-grained deposits, often flocculent in the(More)
The routes calcium might take across the mantle to the shell have been investigated with various electron-microscopical techniques in the freshwater snailBiomphalaria glabrata (Planorbidae, Basommatophora). In chemically-fixed tissue, calcium was precipitated with a tannic acid-antimonate technique in predominantly the intercellular spaces of the outer(More)
The energy-filtering electron microscopical modes of electron energy-loss spectroscopy (EELS) and electron spectroscopic imaging (ESI) have been applied to the cytochemical detection of Ca(2+)-ATPase activity in synaptic terminals in the brain of a cichlid fish. Using a recently developed modification of an enzyme-histochemical method, cerium phosphate was(More)