scholarly journals Influence of temperature acclimatization on the temperature-dependence and ouabain-sensitivity of goldfish intestinal adenosine triphosphatase

1967 ◽  
Vol 105 (1) ◽  
pp. 65-71 ◽  
Author(s):  
M W Smith
Keyword(s):  
Temperature Dependence ◽  
Intestinal Mucosa ◽  
Membrane Fraction ◽  
Adenosine Triphosphatase ◽  
Differential Centrifugation ◽  
Na Transport ◽  
Influence Of Temperature ◽  
Ouabain Sensitivity ◽  
Incubation Temperatures ◽  
Environmental Temperatures

1. Homogenates of goldfish intestinal mucosa were separated into various fractions by differential centrifugation. Both adenosine-triphosphatase and β-glycerophosphatase activities were found to be concentrated mainly in a membrane fraction which sedimented after 1200000g-min. 2. This membrane adenosine-triphosphatase system was activated by Na++K+ and inhibited by ouabain. 3. The ouabain-sensitive adenosine-triphosphatase activity was high and the ouabain-insensitive activity low in membrane fractions prepared from fish acclimatized previously to 8°. The opposite was true for fish acclimatized to 30°. 4. The Arrhenius plots of ouabain-sensitive and ouabain-insensitive adenosine-triphosphatase activities, measured from 5° to 30°, showed discontinuities at incubation temperatures that varied with the previous acclimatization temperature of the fish. 5. It is considered that modification of the membrane adenosine-triphosphatase system in goldfish intestinal mucosa may serve to regulate Na+ transport at different environmental temperatures.

scholarly journals Influence of temperature acclimatization on the ionic activation of goldfish intestinal adenosine triphosphatase

1968 ◽  
Vol 107 (5) ◽  
pp. 691-698 ◽  
Author(s):  
M W Smith ◽  
V. E. Colombo ◽  
E A Munn
Keyword(s):  
Adenosine Triphosphatase ◽  
Environmental Temperature ◽  
Membrane System ◽  
Density Gradients ◽  
Differential Centrifugation ◽  
Influence Of Temperature ◽  
Anterior Intestine ◽  
Environmental Temperatures

1. An adenosine triphosphatase membrane system, dependent on Mg2+ and activated further by Na++K+, was prepared from goldfish anterior intestine by differential centrifugation of homogenized intestinal scrapings. 2. The affinity of this preparation for Na+ in the presence of K++Mg2+, for K+ in the presence of Na++Mg2+ and for Mg2+ alone, measured at 37°, did not depend on the previous environmental temperature of the fish. When Na++K+ were added to preparations from 8°-acclimatized fish the affinity for Mg2+ increased; this was not seen with preparations from 30°-acclimatized fish. 3. Part of the Mg2+-activated adenosine triphosphatase was inhibited by Na+ and the amount of inhibition appeared to increase at high acclimatization temperatures. 4. This Na+-inhibited adenosine triphosphatase was separated from the (Na++K+)-activated enzyme by centrifugation on sucrose density gradients. 5. Preparations from 8°-acclimatized fish contained less Mg2+-activated and more (Na++K+)-activated adenosine triphosphatase than did similar fractions from 30°-acclimatized fish. 6. Acclimatization to different environmental temperatures might involve one form of adenosine triphosphatase changing to another. The origin of various membranes seen in microsomal fractions must, however, be established before this hypothesis can be tested further.

Cl- -HCO3- -stimulated ATPase in intestinal mucosa of Aplysia

1985 ◽  
Vol 248 (2) ◽  
pp. R241-R248 ◽  
Author(s):  
G. A. Gerencser ◽  
S. H. Lee
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Intestinal Mucosa ◽  
Membrane Fraction ◽  
Transport Mechanism ◽  
Plasma Membranes ◽  
Sucrose Density Gradient ◽  
Disulfonic Acid ◽  
Differential Centrifugation ◽  
Optimum Ph

The serosa negative transepithelial potential difference across Aplysia intestine is generated by a Na+-independent, active electrogenic Cl- absorptive mechanism. In an attempt to clarify the Cl- absorptive mechanism an anion-stimulated ATPase was prepared from plasma membranes from Aplysia enterocytes utilizing differential centrifugation and sucrose density gradient techniques. ATPase activity, which could be activated by either Cl- or HCO3-, was found in the plasma membrane fraction. Maximal anion-ATPase activity was achieved with either 25 mM Cl- or 25 mM HCO3-. The apparent Km for Cl- activation of the ATPase was 10.3 mM, whereas apparent Km for HCO3- was 9.7 mM. ATP was the most effective nucleotide substrate for both HCO3- and Cl- -ATPase activities, whereas optimum pH for both activities was 7.8. These enzyme activities were inhibited more than 30% by thioacyanate (10 mM). Acetazolamide and vanadate were also found to strongly inhibit both Cl- and HCO3- -ATPase activities, whereas 10 microM 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid, 1 mM furosemide, or 1 mM ouabain had little or no effect. These results are consistent with the hypothesis that the active Cl- transport mechanism in Aplysia intestine could be a Cl- -HCO3- -stimulated ATPase found in the enterocyte plasma membrane.

scholarly journals STUDIES OF L FORMS AND PROTOPLASTS OF GROUP A STREPTOCOCCI

1963 ◽  
Vol 117 (3) ◽  
pp. 377-399 ◽  
Author(s):  
Earl H. Freimer
Keyword(s):  
Cell Wall ◽  
Membrane Fraction ◽  
Group A Streptococci ◽  
Differential Centrifugation ◽  
Bacterial Membranes ◽  
Group A ◽  
Antigenic Material ◽  
A Cell ◽  
Membrane Antigens ◽  
Gram Positive Cocci

Intact bacterial membranes have been isolated from protoplasts prepared from Group A streptococci by a cell wall-dissolving enzyme. A membrane fraction with identical chemical and serological properties has been obtained by differential centrifugation of mechanically disrupted streptococci. The membrane is chemically distinct from the cell wall and is composed of 72 per cent protein, 26 per cent lipid, and 2 per cent carbohydrate. Capillary precipitin tests and analysis by microdiffusion have demonstrated that the membrane contains antigens distinct from those of the cell wall and from those of the cytoplasm which it envelops. Evidence is presented which demonstrates that this antigenic material is common to the membranes of Group A streptococci, and that it can be distinguished by immunodiffusion from related antigenic substances present in membranes of several other serological groups of hemolytic streptococci. This antigenic material does not cross-react with the membrane antigens of other Gram-positive cocci.

scholarly journals ADENOSINE TRIPHOSPHATE-LINKED CONCENTRATION OF CALCIUM IONS IN A PARTICULATE FRACTION OF RABBIT MUSCLE

1962 ◽  
Vol 14 (3) ◽  
pp. 389-400 ◽  
Author(s):  
Setsuro Ebashi ◽  
Fritz Lipmann
Keyword(s):  
Skeletal Muscle ◽  
Endoplasmic Reticulum ◽  
Electron Micrographs ◽  
Calcium Ions ◽  
Calcium Ion ◽  
Membrane Fraction ◽  
Ion Concentration ◽  
Rabbit Muscle ◽  
Differential Centrifugation ◽  
Calcium Ion Concentration

ATPase and ATP-dependent calcium ion concentration was studied with a membrane fraction isolated from homogenized rabbit skeletal muscle by differential centrifugation. Electron micrographs of the fraction indicate that it consists mainly of resealed tubules and vesicles of the endoplasmic reticulum. The up-to-1400-fold concentration of calcium in this fraction might be explained by proposing the existence of an energy-requiring system for the transport of calcium ions into the tubules or vesicles.

scholarly journals Temperature dependence of the indentation size effect

2010 ◽  
Vol 25 (7) ◽  
pp. 1225-1229 ◽  
Author(s):  
Oliver Franke ◽  
Jonathan C. Trenkle ◽  
Christopher A. Schuh
Keyword(s):  
High Temperature ◽  
Size Effect ◽  
Temperature Dependence ◽  
Thermal Activation ◽  
Indentation Size Effect ◽  
Inert Atmosphere ◽  
Length Scale ◽  
Indentation Size ◽  
Influence Of Temperature ◽  
Influence Of Temperature On

The influence of temperature on the indentation size effect is explored experimentally. Copper is indented on a custom-built high-temperature nanoindenter at temperatures between ambient and 200 °C, in an inert atmosphere that precludes oxidation. Over this range of temperatures, the size effect is reduced considerably, suggesting that thermal activation plays a major role in determining the length scale for plasticity.

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