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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 36 (1980), S. 1317-1319 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A rapid silver nitrate impregnation of nerve fibres has been devised to maintain a histochemically detectable acetylcholinesterase activity at the motor end-plates.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 73 (1981), S. 33-37 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Silicotungstic acid (STA), an electron dense substance and a powerful precipitating agent of quaternary ammonium salts such as choline and acetylcholine, was employed on the frog motor end-plate in order to prove that STA reacts with diffusible substance(s) in nerve terminals. Thus, STA treatment and osmium tetroxide (OsO4) fixation were performed in three different ways. No reaction was detectable when STA treatment followed osmification, while simultaneous treatment with STA and OsO4 darkened both presynaptic and synaptic vesicle membranes. When STA was employed directly on fresh tissues which were subsequently fixed by OsO4, small black precipitates were observed in the synaptic vesicles and none on other synaptic structures. The possible reaction of STA with acetylcholine is discussed.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An osmium resistant, thermostable and electron dense precipitate was obtained from cuprous thiocholine iodide (Koelle's precipitate) by a joint interaction with phosphomolybdic acid and OsO4. No diffusion artifact due to the conversion of the primary precipitate to the secondary precipitate was observed, contrary to that seen after (NH4)2S or K3Fe+++ (CN)6 posttreatment of the cuprous thiocholine iodide. In addition, phosphomolybdic acid and OsO4 provided a counterstain effect on the ultrastructural background. By the present modification, Koelle's histochemical method becomes a useful cytochemical method for ultrastructural localization of acetylcholinesterase activity.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A new cytochemical technique is proposed for side by side localization of acetylcholine and of acetylcholinesterase activity of motor end-plate at ultrastructural level. The technique is based on the simultaneous “ionic fixation” of vesicular acetylcholine and of histochemical copper thiocholine precipitate with phosphomolybdic acid: the molybdic heteropolyanion forms insoluble salts with these two quaternary ammonium cations, providing in situ “acetylcholine phosphomolybdate” and “copper thiocholine phosphomolybdate”. Both of them are osmium resistant; the electron dense precipitates allow for a fine localization of acetylcholine and acetylcholinesterase activity at electron microscopic level.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 81 (1984), S. 453-455 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A fresh preparation of frog neuromuscle was fixed at low temperatures (0°–4°C) by means of an “ionic-fixation” procedure which is based on the precipitation of quaternary ammonium cations, such as choline and acetylcholine, with molybdic or tungstic heteropolyanions. A low temperature was used to slow down drastically the biological processus of vesicular exocytosis so that ionic fixation, the speed of which is only slightly influenced by temperature variation, could be performed efficiently. In addition to the conventional point-like precipitate in the synaptic vesicle which is considered to be vesicular acetylcholine, numerous spot-like precipitates were observed in the synaptic cleft. Most of these were contiguous to the active zone, and some were in a paired form and corresponded to the double rows of the synaptic vesicles in contact with active zones. It is concluded that these spot-like precipitates were acetylcholine-like cations of the synaptic vesicles which had been discharged into the synaptic cleft by exocytosis and captured by the ionic fixation procedure. The results are discussed in relation to the vesicular and non-vesicular hypothesis of acetylcholine release.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 72 (1981), S. 369-375 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An immunocytochemical method is proposed for the localization of synaptic acetylcholinesterase (AChE) on ultrathin frozen sections of the electric organ of the electric eel. The immune complex formed is amplified by a non-specific “sandwich” technique and visualized by negative staining. Definite white spots on synaptic cleft seem to correspond to basal lamina AChE molecules.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the original Karnovsky and Roots' method for the localization of acetylcholinesterase (AChE), thiocholine reduces the ferricyanide and cupric ions of this medium competitively, giving simultaneously cupric ferrocyanide (Karnovsky's precipitate) and cuprous thiocholine iodide (Koelle's precipitate) as histochemical products. We modified the method in order to promote the true Karnovsky's reaction, and to slow down the secondary Koelle's reaction by increasing the concentration of the ferricyanide ion from 0.5 mM to 5.0 mM and by decreasing the concentration of the cupric ion from 3.0 mM to 2.5 mM. The cupric ion, complexed with 5 mM sodium citrate in the original method, was further stabilized by the use of 0.1 M citrate buffer in order to prevent the interaction of cupric ion with increased ferricyanide. In order to suppress completely the residual Koelle's precipitate, we used acetylthiocholine chloride as a substrate, instead of acetylthiocholine iodide. The chloride salt of cuprous thiocholine is soluble, contrary to the iodide salt. In addition, the pH of the medium was lowered from 6.0 to 5.0 to avoid artefactual nuclear staining, appearing at a pH beyond 5.5. In this modified medium, Karnovsky's cupric ferrocyanide becomes the sole precipitate at the enzymatic site and this provides fine localization of acetylcholinesterase activity.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The treatment of neuromuscular junctions with phosphomolybdic acid (PMA) and silicotungstic acid (STA) heteropolyanions permits the visualization of electron dense precipitates in the synaptic vesicles of the cholinergic motor nerve terminals. At the light microscopic level, the uncolored molybdenum salt is visualized after reduction to molybdenum blue. The blue coloration is confined to the nerve terminals. Since PMA and STA are known as strong precipitating agents of quaternary ammonium compounds (cations) it is supposed that they have insolubilized in situ the acetylcholine (Ach) of the synaptic vesicles by means of a rapid ionic interaction. Furthermore, in spite of the strong acidity of PMA and STA solutions, the ultrastructure of the treated tissue is not significantly altered but on the contrary seems to be well preserved. The ionic insolubilization of Ach, added to the good preservation of the ultrastructure prompted us to use the term “ionic fixation”.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using a glutaraldehyde-fixed mouse neuromuscular junction, a fine precipitate of copper thiocholine was obtained with Koelle's medium prepared by a mixture of phosphate buffer (pH 5.6–5.9) and copper glycine solution (strongly acidic). The final pHs of these incubation media were very low, being situated between 3.8 and 4.2, respectively. It is well known that phosphate buffer, at such a low pH value, has no buffering effect on the acetic acid of enzymatic hydrolysis. This probably caused a sharp drop of the pH value in the vicinity of the enzymatic site and allowed a fine localization of copper thiocholine, the precipitation of which is pH dependent. Furthermore, the osmification of copper thiocholine in the same phosphate buffer provided a finely localized electron dense product. The chemical nature of the osmified copper thiocholine is discussed.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 68 (1984), S. 169-177 
    ISSN: 1432-2242
    Keywords: Alloplasmic triticale ; Male-sterile triticale ; Wheat cytoplasm ; Aegilops cytoplasm ; Cytoplasmic relationship
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The transfer of cytoplasms of various Triticum and Aegilops species to a hexaploid triticale (‘Rosner’) has been attempted using 30 alloplasmic lines and a euplasmic line of common wheat as cytoplasmic donors. The average rate of F1 hybrid production (seed setting rateXgermination rate) following an ordinary method of crossing is only 0.09%, whereas this rate is increased to 3.1% by use of embryo culture. The first backcross of the F1 plants with triticale pollen is again difficult, the hybrid production being 0.9%. Further backcrosses proceed smoothly in most cases. As a consequence, the following seven cytoplasms have been transferred to triticale: T. dicoccum, T. aestivum, Ae. squarrosa, Ae. cylindrica, Ae. juvenalis, Ae. ovata and Ae. speltoides. None of these alien cytoplasms causes more meiotic instability than does the triticale's own cytoplasm. Two cytoplasms of T. dicoccum and T. aestivum, both belonging to the B plasma type, have no effect upon any of triticale's characters. Two D type cytoplasms of Ae. squarrosa and Ae. cylindrica cause about 50% reduction of male fertility but exert no other remarkable effects. This fact suggests a partial functional compensation of the effect of a 1D chromosome upon interacting with D cytoplasm by a rye chromosome substituting for it in triticale. A D2 cytoplasm of Ae. juvenalis causes earlier heading and complete male sterility, accompanied by some reduction of growth vigor. An M0 type cytoplasm of Ae. ovata and an S type cytoplasm of Ae. speltoides cause a great heading delay, complete male sterility, and severe reduction of vigor. From the viewpoint of triticale breeding, none of these cytoplasms appears superior to the triticale's own cytoplasm. However, from the viewpoint of genetics, the hexaploid triticale is an effective tester for differentiating the B, S, and D plasma types.
    Type of Medium: Electronic Resource
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