THE INFLUENCE OF LIGHT AND DARKNESS ON THE METABOLISM OF RADIOACTIVE GLUCOSE AND GLUTAMINE IN WHEAT LEAVES

1955 ◽  
Vol 33 (2) ◽  
pp. 189-196 ◽  
Author(s):  
R. G. S. Bidwell ◽  
G. Krotkov ◽  
G. B. Reed
Keyword(s):  
Carbon Dioxide ◽  
Staphylococcus Aureus ◽  
Ammonium Nitrate ◽  
Paper Chromatography ◽  
Pyruvic Acid ◽  
Krebs Cycle ◽  
Complete Oxidation ◽  
Glucose Carbon ◽  
Plant Constituents ◽  
Wheat Leaves

C14-Labelled glucose or glutamine was fed to wheat leaves in light or darkness, and several hours later the distribution of activity among the various plant constituents was determined following their separation by paper chromatography. From these data it was concluded that complete oxidation of glutamine to carbon dioxide proceeded at a greater rate in light than in darkness. In light glucose carbon was prevented from reaching pyruvic acid and the Krebs cycle to any great extent, but this block could be reversed by the application of ammonium nitrate to the leaves. Light or darkness had no effect on the respiration of glucose by Staphylococcus aureus.

Studies in the respiratory and carbohydrate metabolism of plant tissues - Experimental studies of the formation of carbon dioxide and of the changes in lactic acid, sucrose and in certain fractions of keto-acids in potato tubers in air following anaerobic conditions

1953 ◽  
Vol 141 (904) ◽  
pp. 321-337 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Lactic Acid ◽  
Pyruvic Acid ◽  
Experimental Studies ◽  
Krebs Cycle ◽  
Plant Tissues ◽  
Potato Tubers ◽  
Anaerobic Conditions ◽  
Co2 Output ◽  
Keto Acids

Barker A Saifl (1953 b ), suggested that the initial rapid increase and the subsequent slower decrease in the CO 2 output of potatoes in air after a peroid under anaerobic conditions might be partly related to a quick formation of pyruvic acid from the accumulated lactic acid and to the respiration of the Pyruvic acid via krebs cycle (krebs & johnson 1937; krebs 1952). Information bearing on the associated changes in pyruvic and α-ketoglutaric acid has now been obtained using a technique (Friedemann & Haugen 1943; Friedemann 1950) which while not fully specific gives values that are known to include true pyruvic acid and true α-ketoglutaric acid as well as non-pyruvic and non-α-ketoglutaric acid material respectively. Associated with the loss of Lactic acid in air after nitrogen and the accompanying increase followed by a decrease in the CO 2 output, Mentioned above, there was first a rapid increase in the content of 'pyruvic' and 'α-ketoglutaric acid' and then a prolonged decrease in these fractions. The analysis of the interrelation between the loss of lactic acid and the production of CO 2 and of the keto-acids, and between the changes in the rate of CO2 output and the changes in the concentration of the keto-acids and of sucrose, is taken up in the next paper in this series (Barker & Mapson 1953).

scholarly journals MECHANISM OF FIXATION OF CARBON DIOXIDE IN THE KREBS CYCLE

1941 ◽  
Vol 139 (1) ◽  
pp. 483-484
Author(s):  
H.G. Wood ◽  
C.H. Werkman ◽  
Allan Hemingway ◽  
A.O. Nier
Keyword(s):  
Carbon Dioxide ◽  
Krebs Cycle ◽  
Fixation Of Carbon Dioxide

THE ENZYMIC AND MORPHOLOGIC ORGANIZATION OF THE MITOCHONDRIA

PEDIATRICS ◽  
1960 ◽  
Vol 26 (3) ◽  
pp. 466-475
Author(s):  
Albert L. Lehninger
Keyword(s):  
Carbon Dioxide ◽  
Citric Acid Cycle ◽  
Krebs Cycle ◽  
Molecular Organization ◽  
Animal Tissues ◽  
Hydrogen Atoms ◽  
Common Pathway ◽  
Text Book ◽  
Acid Cycle ◽  
And Function

In This Paper I shall describe some of the information we have recently obtained regarding the enzymic and molecular organization of the mitochondria, which as you know are very small particulate organelles in the cytoplasm of all aerobic cells. These bodies have been found to catalyze one of the most fundamental activities of the cell, namely, the transformation of the energy yielded by oxidation of foodstuffs into the so-called phosphate-bond energy of adenosine triphosphate. This process of respiration and phosphorylation is extremely complex and involves the interaction of at least seventy different enzymes and coenzymes in an integrated fashion. The mitochondria have a characteristic ultrastructure in which these enzymes are embedded, and it is now possible to consider in some detail the intramitochondrial location and function of these important energy-transforming molecules. First, let us consider the organization of oxidative metabolism in purely biochemical terms. Figure 1 shows the usual text-book representation of the final common pathway of biologic oxidation in animal tissues. You will recall that all three of the major foodstuffs of the cell (carbohydrate, fat and protein) ultimately are degraded in the tissues to a two-carbon unit, namely, acetylcoenzyme A. The acetate group then undergoes oxidation by the Krebs citric acid cycle, and in this process the two carbon atoms of acetate become oxidized to carbon dioxide. The oxidation of acetate is finally completed when pairs of hydrogen atoms are removed from certain of the intermediates of the Krebs cycle by dehydrogenases. These hydrogen atoms, or their equivalent in electrons, pass along the respiratory chain via the cytochromes until they meet molecular oxygen and reduce it to form water.

Corrigendum - Effects of a water stress on the photosynthesis and respiration of wheat ears

1980 ◽  
Vol 31 (5) ◽  
pp. 857
Author(s):  
B Marshall ◽  
RH Sedgley ◽  
PV Biscoe
Keyword(s):  
Carbon Dioxide ◽  
Water Stress ◽  
Maximum Rate ◽  
Dark Respiration ◽  
Light Response ◽  
Grain Filling ◽  
Response Curves ◽  
Rectangular Hyperbola ◽  
Wheat Leaves ◽  
Days After Anthesis

An experiment was conducted on Huntsman winter wheat to investigate the effects of a water stress applied at anthesis on the carbon dioxide exchange of the ears during grain filling. The water stress was created by excluding rain from the soil, not the foliage, of plants growing in the field. Control plants were well watered throughout the period when the treatment was imposed. At intervals for 32 days after anthesis, detailed measurements were made of the photosynthetic rate of ears at different irradiances and rates of ear dark respiration. The measurements were analysed by using the photosynthesis-light response model developed by Marshall and Biscoe (1980) for wheat leaves with a modification for the pathway of respiration from the grains to the glumes. The model is a non-rectangular hyperbola and uses four parameters: Pn,max (maximum rate of net photosynthesis), Rd (rate of dark respiration), � (photochemical efficiency at low light), and F (ratio of physical to total resistance to diffusion of carbon dioxide). Analysis showed that in wheat ears during grain filling, photosynthesis can be treated as occurring predominantly in the glumes and respiration in the grains. The shape of the photosynthesis-light response curves for ears from both treatments were similar, but differed from those for wheat leaves because the maximum rates of photosynthesis were reached more gradually with increasing irradiance. However, the measured response curves were still better fitted by the model than a rectangular hyperbola which has often been used in the past. The water stress at anthesis decreased the maximum rate of ear photosynthesis by 0.8 g carbon dioxide m-2 h-1 throughout the grain-filling period. Initially, the rates of ear respiration were the same, but 32 days after anthesis the treatment had decreased ear respiration rate from 0.04 to 0.01 g carbon dioxide h-1/grain.

THE ROLE OF KETO ACIDS IN PHOTOSYNTHETIC CARBON DIOXIDE ASSIMILATION

1956 ◽  
Vol 34 (1) ◽  
pp. 511-519 ◽  
Author(s):  
G. H. N. Towers ◽  
D. C. Mortimer
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Sugar Beet ◽  
Aspartic Acid ◽  
Pyruvic Acid ◽  
Carbon Dioxide Assimilation ◽  
Free Air ◽  
Keto Acids ◽  
Photosynthetic Carbon

Of the keto acids identified in leaves of sugar beet and other plants exposed to C14O2, pyruvic acid was found to be the only one labelled in light periods up to 45 sec. α-Ketoglutaric and glyoxylic acids became radioactive after about 45 sec. Radioactive hydroxypyruvate was not identified under these conditions and labelled oxaloacetate was detected only in trace amounts after 60 sec. in Scenedesmus. In contrast glycine and serine were labelled after 10 sec. under comparable conditions and aspartic acid was appreciably labelled after 30 sec. The effect on the radioactivity of the keto acids of an additional period intracer-free air, with and without light, as well as the dark incorporation of C14O2 was studied. These results are discussed in relation to the role of the ketoacids in photosynthesis. It is concluded that the synthesis of amino acids such as glycine, serine, and aspartic acid may be effected by mechanisms other than transamination in green leaves in the light.

Enzymatic synthesis of pyruvic acid from acetaldehyde and carbon dioxide

2001 ◽  
pp. 1800-1801 ◽  
Author(s):  
Masaya Miyazaki ◽  
Mitsukuni Shibue ◽  
Kazuya Ogino ◽  
Hiroyuki Nakamura ◽  
Hideaki Maeda
Keyword(s):  
Carbon Dioxide ◽  
Pyruvic Acid ◽  
Enzymatic Synthesis

scholarly journals Biological synthesis of oxaloacetic acid from pyruvic acid and carbon dioxide

1940 ◽  
Vol 34 (10-11) ◽  
pp. 1383-1395 ◽  
Author(s):  
H. A. Krebs ◽  
L. V. Eggleston
Keyword(s):  
Carbon Dioxide ◽  
Pyruvic Acid ◽  
Biological Synthesis ◽  
Oxaloacetic Acid
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