The effect of hydrogen ion concentration on the uptake and metabolism of glucose-U-14C by auxin-treated pea root tips

1968 ◽  
Vol 46 (7) ◽  
pp. 945-947
Author(s):  
W. K. Kim ◽  
R. G. S. Bidwell
Keyword(s):  
Marked Effect ◽  
Hydrogen Ion ◽  
Intermediary Metabolism ◽  
Ion Concentration ◽  
Root Tips ◽  
Hydrogen Ion Concentration ◽  
Specific Effects ◽  
Inhibition Of Growth ◽  
Pea Root ◽  
Uptake And Metabolism

Hydrogen ion concentration has been found to have a marked effect on the response of pea root tips to auxins. In addition, auxins have been shown to exert certain specific effects on the metabolism of 14C-labelled glucose and related metabolites. The present experiments show that varying the pH modifies the auxin effects on intermediary metabolism and growth in entirely different ways. It is concluded that the auxin inhibition of growth must operate through a different mechanism than the effect on inter mediary metabolism of glucose.

scholarly journals A Colorimetric Method for Studying the Dissociation of Oxyhæmocyanin suitable for Class Work

1925 ◽  
Vol 13 (4) ◽  
pp. 970-980 ◽  
Author(s):  
C. F. A. Pantin ◽  
Lancelot T. Hogben
Keyword(s):  
Marked Effect ◽  
Colorimetric Method ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Dissociation Curve ◽  
Hydrogen Ion Concentration ◽  
Laboratory Class ◽  
Wide Range ◽  
Increasing Temperature ◽  
Limits Of Error

1. A simple colorimetric method for plotting the dissociation curve of haemocyanin is indicated. The limits of error are within 5 per cent. The simplicity of the method commends it for laboratory class work.2. The effect of hydrogen ion concentration on the dissociation of the hsemocyanins of the crustacean Palinurus and the pulmonate Helix have been compared. In the snail change of hydrogen ion concentration over a wide range was not found to affect the dissociation of the hsemocyanin: in 'the crustacean there is a marked effect similar to that seen in the dissociation of hæmoglobin.3. The similarity of crustacean hsemocyanin to haemoglobin is also seen in that increasing temperature depresses the dissociation curve. The effects of certain salts upon haemocyanin. have also been recorded.

scholarly journals ION SERIES AND THE PHYSICAL PROPERTIES OF PROTEINS

1921 ◽  
Vol 3 (3) ◽  
pp. 391-414 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Physical Properties ◽  
Osmotic Pressure ◽  
Opposite Sign ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Depressing Effect ◽  
Protein Solution ◽  
Hydrogen Ion Concentration ◽  
Specific Effects ◽  
Protein Ions

1. Ions with the opposite sign of charge as that of a protein ion diminish the swelling, osmotic pressure, and viscosity of the protein. Ions with the same sign of charge as the protein ion (with the exception of H and OH ions) seem to have no effect on these properties as long as the concentrations of electrolytes used are not too high. 2. The relative depressing effect of different ions on the physical properties of proteins is a function only of the valency and sign of charge of the ion, ions of the same sign of charge and the same valency having practically the same depressing effect on gelatin solutions of the same pH while the depressing effect increases rapidly with an increase in the valency of the ion. 3. The Hofmeister series of ions are the result of an error due to the failure to notice the influence of the addition of a salt upon the hydrogen ion concentration of the protein solution. As a consequence of this failure, effects caused by a variation in the hydrogen ion concentration of the solution were erroneously attributed to differences in the nature of the ions of the salts used. 4. It is not safe to draw conclusions concerning specific effects of ions on the swelling, osmotic pressure, or viscosity of gelatin when the concentration of electrolytes in the solution exceeds M/16, since at that concentration the values of these properties are near the minimum characteristic of the isoelectric point.

The Absorption of Oxygen by Plaice Eggs

1928 ◽  
Vol 5 (3) ◽  
pp. 177-184
Author(s):  
S. T. BURFIELD
Keyword(s):  
Carbon Dioxide ◽  
Large Volume ◽  
Marked Effect ◽  
Sea Water ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Oxygen Absorption ◽  
Closed Volume ◽  
Hydrogen Ion Concentration ◽  
Rate Of Absorption

1. The rate of oxygen absorption by plaice eggs, contained in a closed volume of sea water, falls when the eggs and water are allowed to remain relatively quiescent. This fall takes place even when a large volume of water is used. 2. It has been shown that small changes in the partial pressure of dissolved oxygen do not appreciably affect the rate of absorption, so that this is not the factor concerned in the fall. 3. The rate of oxygen absorption in a closed volume of sea water does not fall if the eggs be frequently moved. 4. The removal of eggs to a closed volume of fresh sea water at the end of a period prevents the rate of absorption from falling during a second equal period. 5. The removal of eggs to a closed volume of "used" sea water at the end of a period causes the rate of absorption to fall during a second equal period. 6. The addition of urea in small quantities to the sea water has no effect on oxygen absorption. 7. The addition of carbon dioxide to the sea water has a marked effect in lowering the rate of oxygen absorption, and the accumulation of excreted carbon dioxide is probably the factor causing the fall in absorption mentioned under paragraphs 1 and 5. 8. This effect is possibly directly due to the alteration in the hydrogen ion concentration produced by the carbon dioxide. 9. The Respiratory Quotient of young plaice eggs is about .75.

scholarly journals FACTORS AFFECTING THE PRODUCTION OF CHROMOSOME ABERRATIONS BY CHEMICALS

1956 ◽  
Vol 2 (5) ◽  
pp. 543-555 ◽  
Author(s):  
B. A. Kihlman
Keyword(s):  
Oxygen Tension ◽  
Chromosome Aberrations ◽  
Maleic Hydrazide ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Root Tips ◽  
Hydrogen Ion Concentration ◽  
Factors Affecting ◽  
Influence Of Temperature

In the present paper, the results of a study on the influence of temperature, hydrogen ion concentration, and oxygen tension on the production of chromosome aberrations in Vicia root tips by maleic hydrazide (MH), di-(2, 3-epoxypropyl)ether (DEPE), and 8-ethoxycaffeine (EOC), are described. Variations in the hydrogen ion concentration of the treatment solutions did not significantly influence the effect of EOC and DEPE. In contrast, the MH effect was considerably diminished by raising the pH from 4.7 to 7.3. A marked increase in the frequencies of aberrations produced by DEPE and MH was obtained by raising the temperature from 3° to 25°C. The effect of EOC increased with rising temperature up to 12°C. With a further rise in temperature the effect of EOC decreased, so that at 25°C. it was of about the same magnitude as at 3°C. The effect of EOC was completely inhibited, and that of MH partly so, when during the treatment (1) oxygen was excluded from the solution, (2) respiration was inhibited by azide or cyanide, or (3) phosphorylation was uncoupled from respiration by 2, 4-dinitrophenol (DNP). Pretreatments with DNP had a similar effect, but posttreatments did not influence the frequencies of aberrations. The effect of DEPE was unchanged by anoxia. Pre- or posttreatments with DNP did not change the total number of aberrations produced by DEPE, but the appearance of the effect was considerably delayed. The results are discussed.

scholarly journals THE INFLUENCE OF HYDROGEN ION CONCENTRATION ON THE INACTIVATION OF PEPSIN SOLUTIONS

1920 ◽  
Vol 2 (5) ◽  
pp. 465-470 ◽  
Author(s):  
John H. Northrop
Keyword(s):  
Marked Effect ◽  
Strong Acid ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Slow Increase ◽  
Hydrogen Ion Concentration ◽  
Optimum Range ◽  
Enzyme Solution

1. Pepsin in solution at 38°C. is most stable at a hydrogen ion concentration of about 10–5 (pH 5.0). 2. Increasing the hydrogen ion concentration above pH 5.0 causes a slow increase in the rate of destruction of pepsin. 3. Decreasing the hydrogen ion concentration below pH 5.0 causes a very rapid increase in the rate of destruction of the enzyme. 4. Neither the purity of the enzyme solution nor the anion of the acid used has any marked effect on the rate of destruction or on the zone of hydrogen ion concentration in which the enzyme is most stable. 5. The existence of an optimum range of hydrogen ion concentration for the digestion of proteins by pepsin cannot be explained by the destruction of the enzyme by either too weak or too strong acid.

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