scholarly journals Cytochemical localization of ecto-ATPases in rat neurohypophysis.

1996 ◽  
Vol 44 (2) ◽  
pp. 103-111 ◽  
Author(s):  
S Thirion ◽  
J D Troadec ◽  
G Nicaise
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Atpase Activity ◽  
Outer Surface ◽  
Nerve Endings ◽  
Glutaraldehyde Fixation ◽  
Cytochemical Localization ◽  
Cytochemical Method ◽  
Ca Pump ◽  
Dependent Atpase

We studied the distribution of Ca(2+)- or Mg(2+)-dependent ATPase activity in rat neurohypophysis using the lead cytochemical method of Ando et al. In electron microscopy, precipitates were found lining the outer surface of the plasma membrane surrounding nerve endings and pituicytes. These precipitates were believed to represent the activity of ecto-ATPases (as opposed to Ca pump ATPases) for the following reasons: there was equal activation by Ca2+ in the absence of Mg2+ or Mg2+ in the absence of Ca2+; the effects of the two ions were not additive; there was activation by ATP or GTP; and there was resistance to glutaraldehyde fixation, to high (10 mM) Ca2+ concentrations, and to various inhibitors such as NEM, vanadate, oligomycin, quercetin, p-chloromercuribenzoate, ouabain, and levamisole. Cytosolic activity observed in certain nerve endings in the same conditions of incubation but more sensitive to NEM is also described and discussed.

Immunological evidence for the presence of latent Ca2⊕ dependent ATPase and carboxydismutase on the thylakoid surface

1970 ◽  
Vol 25 (6) ◽  
pp. 613-618 ◽  
Author(s):  
C. Gamini Kannangara ◽  
Doris van Wyk ◽  
Wilhelm Menke
Keyword(s):  
Electron Microscopy ◽  
Acetic Acid ◽  
Nicotiana Tabacum ◽  
Atpase Activity ◽  
Enzymatic Activity ◽  
Outer Surface ◽  
Coupling Factor ◽  
Ethylene Diamine ◽  
Cross Reactions ◽  
Dependent Atpase

Antibodies were prepared against carboxydismutase and latent Ca2⊕ dependent ATPase (coupling factor) purified from Nicotiana tabacum. The antibodies against carboxydismutase inhibit the enzymatic activity of the purified protein, while those against coupling factor inhibit the Ca2® dependent ATPase activity of the protein as well as the photophosphorylation of the chloroplasts. The antisera against these two proteins agglutinate the isolated lamellar systems of chloroplasts. The lamellar systems after repeated washes with ethylene diamine tetra-acetic acid loose their capacity to agglutinate with the antibodies. So treated lamellar systems regain their capacity to agglutinate when preincubated with purified coupling factor and carboxydismutase. It is concluded that coupling factor and carboxydismutase molecules are present on the outer surface of the thylakoids. The antisera against the proteins isolated from Nicotiana show cross reactions with preparations of Antirrhinum. Coupling factor and carboxydismutase are non-uniformly distributed on the surface of thylakoids. Electron microscopy shows no evidence that coupling factor represent knobs attached to the surface of the thylakoids.

scholarly journals ELECTRON MICROSCOPIC STUDY OF THE ATPASE ACTIVITY OF THE BAI STRAIN A (MYELOBLASTOSIS) AVIAN TUMOR VIRUS

1962 ◽  
Vol 15 (3) ◽  
pp. 451-462 ◽  
Author(s):  
Alex B. Novikoff ◽  
Guy de Thé ◽  
D. Beard ◽  
J. W. Beard
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Atpase Activity ◽  
Light Microscopy ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Frozen Sections ◽  
Electron Microscopic ◽  
Tumor Virus

Thymus glands of chicks with leukemia induced by BAI strain A (myeloblastosis) virus were fixed in cold 4 per cent formaldehyde-sucrose. Frozen sections were incubated in the ATPase medium of Wachstein and Meisel and studied by light microscopy and electron microscopy. The ATPase activity of the virus is localized to the outermost membrane of the virus. The membrane of the blast-like cells of the thymus cortex from which the virus emerges, by budding, also possesses such activity. It appears likely that the outermost membrane of the virus is derived from the plasma membrane of these cells.

scholarly journals THE FINE STRUCTURAL LOCALIZATION OF ACETYLCHOLINESTERASE AT THE MYONEURAL JUNCTION

1962 ◽  
Vol 12 (2) ◽  
pp. 247-262 ◽  
Author(s):  
Russell J. Barrnett
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Axon Terminal ◽  
Myoneural Junction ◽  
Cytochemical Localization ◽  
Structural Localization ◽  
Terminal Axon ◽  
Esterolytic Activity ◽  
Relationship Of ◽  
The Relationship

A study of the cytochemical localization of acetylcholiriesterase activity, combining histochemistry with electron microscopy, showed that the final product of the reaction, which was deposited at or near enzyme sites, occurred at four places in the myoneural junction. These included: plasma membrane of the muscle covering the junctional folds, the primary and secondary synaptic clefts, parts of the plasma membrane covering the axon terminal, and vesicular structures in the terminal axoplasm. No reaction occurred in the presence of 10-4 eserine or DFP, whereas 10-5 DFP inhibited the reaction at all sites except in the vesicles of the terminal axon. These findings are discussed with reference to the histochemical method used and to the occurrence of esterolytic activity in the vesicles, as well as to some of the current hypotheses concerning the relationship of the site of acetylcholinesterase and synaptic transmission.

scholarly journals Inhibitory antibodies to plasmalemmal Ca2+-transporting ATPases. Their use in subcellular localization of (Ca2+ + Mg2+)-dependent ATPase activity in smooth muscle

1985 ◽  
Vol 231 (3) ◽  
pp. 737-742 ◽  
Author(s):  
J Verbist ◽  
F Wuytack ◽  
L Raeymaekers ◽  
R Casteels
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Muscle ◽  
Plasma Membrane ◽  
Atpase Activity ◽  
Membrane Fraction ◽  
Transport Atpase ◽  
Calmodulin Binding ◽  
Dependent Atpase ◽  
Inhibitory Antibodies ◽  
Stimulation Of

Antibodies directed against the purified calmodulin-binding (Ca2+ + Mg2+)-ATPase [(Ca2+ + Mg2+)-dependent ATPase] from pig erythrocytes and from smooth muscle of pig stomach (antral part) were raised in rabbits. Both the IgGs against the erythrocyte (Ca2+ + Mg2+)-ATPase and against the smooth-muscle (Ca2+ + Mg2+)-ATPase inhibited the activity of the purified calmodulin-binding (Ca2+ + Mg2+)-ATPase from smooth muscle. Up to 85% of the total (Ca2+ + Mg2+)-ATPase activity in a preparation of KCl-extracted smooth-muscle membranes was inhibited by these antibodies. The (Ca2+ + Mg2+)-ATPase activity and the Ca2+ uptake in a plasma-membrane-enriched fraction from this smooth muscle were inhibited to the same extent, whereas in an endoplasmic-reticulum-enriched membrane fraction the (Ca2+ + Mg2+)-ATPase activity was inhibited by only 25% and no effect was observed on the oxalate-stimulated Ca2+ uptake. This supports the hypothesis that, in pig stomach smooth muscle, two separate types of Ca2+-transport ATPase exist: a calmodulin-binding ATPase located in the plasma membrane and a calmodulin-independent one present in the endoplasmic reticulum. The antibodies did not affect the stimulation of the (Ca2+ + Mg2+)-ATPase activity by calmodulin.

scholarly journals Effects of detergents on Na+ + K+-dependent ATPase activity in plasma-membrane fractions prepared from frog muscles. Studies of insulin action on Na+ and K+ transport

1987 ◽  
Vol 246 (3) ◽  
pp. 583-588 ◽  
Author(s):  
M Omatsu-Kanbe ◽  
H Kitasato
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Skeletal Muscles ◽  
Rana Catesbeiana ◽  
Insulin Binding ◽  
Maximum Activity ◽  
Detergent Concentration ◽  
Control Value ◽  
Dependent Atpase ◽  
K Transport

The increase in Na+/K+ transport activity in skeletal muscles exposed to insulin was analysed. Plasma-membrane fractions were prepared from frog (Rana catesbeiana) skeletal muscles, and examination of the Na,K-ATPase (Na+ + K+-dependent ATPase) activity showed that it was insensitive to ouabain. In contrast, plasma-membrane fractions prepared from ouabain-pretreated muscles, by the same procedures, showed extremely low Na,K-ATPase activity. On adding saponin to the membrane suspension, the Na,K-ATPase activity increased, according to the detergent concentration. The maximum activity was about twice the control value, at 0.33 mg of saponin/mg of protein. Thus saponin makes vesicle membranes leaky, allowing ouabain in assay solutions to reach receptors on the inner surface of vesicles. Addition of insulin to saponin-treated membrane suspensions had no effect on the Na,K-ATPase activity, whereas the maximum activity of Na,K-ATPase in whole muscles was stimulated by exposure to insulin. The results show that the stimulation of Na+/K+ transport by insulin is not directly due to insulin binding to receptors on the cell surface, but rather support the view that the increase in the Na,K-ATPase induced by insulin requires an alteration of intracellular events.

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