NITRIFICATION UNDER AND AFTER ALFALFA, BROME, TIMOTHY, AND WESTERN RYE GRASS: IV. OXIDATION-REDUCTION POTENTIALS AND CARBON DIOXIDE PRODUCTION

1940 ◽  
Vol 18c (4) ◽  
pp. 142-150
Author(s):  
J. G. Malloch ◽  
R. S. Young
Keyword(s):  
Carbon Dioxide ◽  
Crop Residues ◽  
Carbon Dioxide Production ◽  
Redox Potentials ◽  
Initial Value ◽  
Forage Plants ◽  
Reduction Potentials ◽  
Oxidation Reduction ◽  
Micro Organisms ◽  
Decomposing Residues

Changes in the redox potentials of the soils and crop residues were caused mainly by the action of micro-organisms. No relation between the potential measurements and the yield or composition of the crops in the field could be demonstrated. All four forage plants have some fraction that was responsible for a marked drift in potential, but which disappeared early in the process of decomposition.The greatest production of carbon dioxide occurred in soils under the hay crops, and it decreased with lapse of time after breaking. The production was greatest under and after alfalfa followed by brome. When the composition of the crop residues is taken into account, a relation between the carbon dioxide production and nitrate production can be demonstrated. The carbon dioxide production of decomposing residues decreases rapidly from a high initial value, giving further evidence of the presence of a readily decomposable constituent.

THE AEROBIC DECOMPOSITION OF GLUCOSE IN PODSOL SOILS

1939 ◽  
Vol 17c (4) ◽  
pp. 109-124 ◽  
Author(s):  
P. H. H. Gray ◽  
C. B. Taylor
Keyword(s):  
Carbon Dioxide ◽  
Biological Activity ◽  
Carbon Dioxide Production ◽  
Potassium Nitrate ◽  
Food Material ◽  
Early Stages ◽  
Aerobic Decomposition ◽  
Micro Organisms

The decomposition of glucose in samples from cultivated podsol soils of the Appalachian upland region of Quebec Province was effected rapidly by aerobic micro-organisms without the aid of added nitrogen. Potassium nitrate stimulated the rate of carbon dioxide production from glucose added to soil; the rate increased chiefly during the early stages while glucose was still present, and bacterial numbers were rising. Fungi developed high numbers later than the bacteria; they developed especially in soil to which glycine was added with the glucose. Biological activity was stimulated in soils in which glucose had previously been decomposed. The decomposition of the glucose appears to release other sources of available food material.

scholarly journals Oxidation--reduction potentials of turkey liver xanthine dehydrogenase and the origins of oxidase and dehydrogenase behaviour in molybdenum-containing hydroxylases

1977 ◽  
Vol 163 (2) ◽  
pp. 279-289 ◽  
Author(s):  
M J Barber ◽  
R C Bray ◽  
R Cammack ◽  
M P Coughlan
Keyword(s):  
Uric Acid ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Xanthine Dehydrogenase ◽  
Resonance Spectroscopy ◽  
Redox Potentials ◽  
Paramagnetic Resonance ◽  
Reduction Potentials ◽  
Oxidation Reduction ◽  
Temperature Electron ◽  
Full Reduction

Redox potentials for the various centres in the enzyme xanthine dehydrogenase (EC 1.2.1.37) from turkey liver determined by potentiometric titration in the presence of mediator dyes, with low-temperature electron-paramagnetic-resonance spectroscopy. Values at 25 degrees C in pyrophosphate buffer, pH 8.2, are: Mo(VI)/Mo(V)(Rapid),-350 +/- 20mV; Mo(V) (Rapid)/Mo(IV), -362 +/- 20mV; Fe-S Iox./Fe-S Ired., -295 +/- 15mV; Fe-S IIox./Fe-S IIred., -292 +/- 15mV; FAD/FADH,-359+-20mV; FADH/FADH2, -366 +/- 20mV. This value of the FADH/FADH2 potential, which is 130mV lower than the corresponding one for milk xanthine oxidase [Cammack, Barber & Bray (1976) Biochem. J. 157, 469-478], accounts for many of the differences between the two enzymes. When allowance is made for some interference by desulpho enzyme, then differences in the enzymes' behaviour in titration with xanthine [Barber, Bray, Lowe & Coughlan (1976) Biochem. J. 153, 297-307] are accounted for by the potentials. Increases in the molybdenum potentials of the enzymes caused by the binding of uric acid are discussed. Though the potential of uric acid/xanthine (-440mV) is favourable for full reduction of the dehydrogenase, nevertheless, during turnover, for kinetic reasons, only FADH and very little FADH2 is produced from it. Since only FADH2 is expected to react with O2, lack of oxidase activity by the dehydrogenase is explained. Reactivity of the two enzymes with NAD+ as electron acceptor is discussed in relation to the potentials.

STUDIES ON THE METABOLISM OF CEREAL GRAINS: III. THE INFLUENCE OF ATMOSPHERIC HUMIDITY AND MOULD INFECTION ON THE CARBON DIOXIDE OUTPUT OF WHEAT

1944 ◽  
Vol 22c (4) ◽  
pp. 150-161 ◽  
Author(s):  
William Leach
Keyword(s):  
Carbon Dioxide ◽  
Relative Humidity ◽  
Carbon Dioxide Production ◽  
Cereal Grains ◽  
Atmospheric Humidity ◽  
Experimental Procedure ◽  
Carbon Dioxide Output ◽  
Micro Organisms

Under the experimental procedure used in these researches it was found that wheat, when kept at 25 °C. in atmospheres of relative humidities between approximately 92 and 100%, showed a continuously accelerating rate of carbon dioxide output. This acceleration of rate increased as the relative humidity of the surrounding air was increased and was more pronounced in wheat from which the germs had been removed than in undamaged wheat. Where unlimited absorption of water and germination of the wheat are prevented, the carbon dioxide production by the grain is due almost entirely to the respiration of micro-organisms that infect it.

scholarly journals Studies on the Oxidation-Reduction Potentials of Heme Proteins

1965 ◽  
Vol 240 (8) ◽  
pp. 3317-3324
Author(s):  
Maurizio Brunori ◽  
Jeffries Wyman ◽  
Eraldo Antonini ◽  
Alessandro Rossi-Fanelli
Keyword(s):  
Heme Proteins ◽  
Reduction Potentials ◽  
Oxidation Reduction
Sign in / Sign up

Export Citation Format

Share Document