ASPECTS OF DECOMPOSITION OF CELLULOSE IN CANADIAN SOILS: II. NITRATE NITROGEN LEVELS AND CARBON DIOXIDE EVOLUTION

1960 ◽  
Vol 6 (3) ◽  
pp. 317-323 ◽  
Author(s):  
H. T. Tribe

The effect of addition of cellulose film on the level of nitrate in a mull humus soil was studied over a period of 16 weeks. During the early stages of decomposition, nitrate was taken up from the soil, leaving it deficient in nitrate for up to 7 weeks. In later stages of decomposition, some of this nitrate was released again. Carbon dioxide was produced from the cellulose film over the whole experimental period. The results were broadly correlated with previous observations on the succession of microorganisms and fauna on cellulose film. The role of the fauna in nitrogen mineralization is discussed.

1959 ◽  
Vol 37 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Mary S. Spencer

The role of phosphorylation in fruit ripening was investigated by the introduction of a phosphorylation uncoupling agent, 2,4-dinitrophenol (DNP), into intact fruit. DNP produced a large increase in carbon dioxide evolution by mature green tomatoes, but not by tomatoes in earlier or later stages of maturity. In contrast to its effect on carbon dioxide production, DNP treatment of mature green tomatoes resulted in an immediate depression of ethylene evolution and in failure of the fruit to ripen normally. This suggests a requirement for oxidative phosphorylation for fruit ripening and ethylene production. It was also observed that cell walls of mature green tomatoes treated with the uncoupling agent became wavy and greatly thickened.


1973 ◽  
Vol 12 (2) ◽  
pp. 641-653
Author(s):  
M. J. DUNN ◽  
E. OWEN ◽  
R. B. KEMP

Trypsin-dissociated cells from the muscle tissue of 9-day-old chick embryos were employed to investigate the effects of cycloheximide and a puromycin-cycloheximide mixture on cell aggregation, protein synthesis and respiratory metabolism. Cycloheximide when introduced at a concentration of 10 µg/ml into a suspension of cells in Eagle's MEM inhibited aggregation by 25% at 24 h. At this time an inhibition of 40% was apparent in the presence of a mixture of cycloheximide and puromycin both at a concentration of 10 µg/ml. Both cycloheximide and the cycloheximide-puromycin mixture arrested protein synthesis of rotated cells by 90% within 15 min of introducing the antibiotics into cell suspensions. The antibiotics retained their inhibitory effects on protein synthesis for the 24-h period of rotation. Cycloheximide inhibited cellular oxygen uptake and carbon dioxide evolution of rotated cells by 25% at the end of the 24-h experimental period. At this time an inhibition of 30% was observed in the presence of the cycloheximide-puromycin mixture. The release of radioactive carbon dioxide by cycloheximide-treated cells was inhibited by 46% at 24 h. In the presence of the antibiotic mixture, 14CO2 release was inhibited by 30% at 4 h, but after 8 h very little further 14CO2 was evolved. As a control, puromycin (10 µg/ml) inhibited cell aggregation and respiration to an extent similar to that previously reported. The results are discussed in terms of puromycyl peptides producing a metabolic effect on cell aggregation. It is considered that this is additional to the effect of puromycin inhibiting aggregation through the arrest of protein synthesis.


1959 ◽  
Vol 37 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Mary S. Spencer

The role of phosphorylation in fruit ripening was investigated by the introduction of a phosphorylation uncoupling agent, 2,4-dinitrophenol (DNP), into intact fruit. DNP produced a large increase in carbon dioxide evolution by mature green tomatoes, but not by tomatoes in earlier or later stages of maturity. In contrast to its effect on carbon dioxide production, DNP treatment of mature green tomatoes resulted in an immediate depression of ethylene evolution and in failure of the fruit to ripen normally. This suggests a requirement for oxidative phosphorylation for fruit ripening and ethylene production. It was also observed that cell walls of mature green tomatoes treated with the uncoupling agent became wavy and greatly thickened.


ACS Catalysis ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 2121-2133
Author(s):  
Chao Zhang ◽  
Chenxi Cao ◽  
Yulong Zhang ◽  
Xianglin Liu ◽  
Jing Xu ◽  
...  

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