scholarly journals Disulfiram Metabolism in Isolated Mesophyll Cells and Inhibition of Photosynthesis and Cyanide-Resistant Respiration

1984 ◽  
Vol 76 (3) ◽  
pp. 846-848 ◽  
Author(s):  
Alan W. Bown ◽  
John Pullen ◽  
Nancy M. Shadeed
Keyword(s):  
Mesophyll Cells ◽  
Isolated Mesophyll Cells ◽  
Cyanide Resistant Respiration

Cyanide-resistant respiration in isolated Asparagus mesophyll cells

1984 ◽  
Vol 62 (6) ◽  
pp. 1122-1126 ◽  
Author(s):  
Nancy M. Shadeed ◽  
Alan W. Bown
Keyword(s):  
Alternative Pathway ◽  
Potassium Cyanide ◽  
Antimycin A ◽  
Mesophyll Cells ◽  
Atp Levels ◽  
Energy Conserving ◽  
Sequential Addition ◽  
Tetraethylthiuram Disulfide ◽  
Energy Dependent ◽  
Cyanide Resistant Respiration

The inhibitors of oxidative phosphorylation antimycin A (0.5 μg/mL), oligomycin (0.01 mg/mL), and sodium azide (3 mM) eliminated energy-dependent H+ efflux from isolated Asparagus mesophyll cells. Antimycin A and oligomycin also reduced ATP levels by 60% or more. In contrast the same concentrations of inhibitors had little or no effect on respiratory O2 consumption. The sequential addition of potassium cyanide to give a final concentration of 5.2 μM resulted in a 60% maximum inhibition of O2 consumption. Subsequent addition of 0.2 mM disulfiram (tetraethylthiuram disulfide), a potent inhibitor of cyanide-resistant respiration, resulted in a further reduction of the oxygen consumption rate. In the absence of cyanide, 0.2 mM disulfiram inhibited O2 consumption by 40 to 80%, depending on the suspension medium. Disulfiram had little or no effect on the ATP levels which varied between 0.7 and 2.2 nmol ATP/106 cells. The results indicate that disulfiram inhibits a non-energy-conserving cyanide-resistant alternative pathway in Asparagus mesophyll cells.

Comparison between tracheary element lignin formation and extracellular lignin-like substance formation during the culture of isolated Zinnia elegans mesophyll cells

Biologia ◽  
2011 ◽  
Vol 66 (1) ◽  
Author(s):  
Yasushi Sato ◽  
Youko Yajima ◽  
Naohito Tokunaga ◽  
Ross Whetten
Keyword(s):  
Peroxidase Activity ◽  
Cell Walls ◽  
Vascular Plants ◽  
Culture Media ◽  
Tracheary Element ◽  
Zinnia Elegans ◽  
Tracheary Elements ◽  
Mesophyll Cells ◽  
Isolated Mesophyll Cells ◽  
Lignin Deposition

AbstractLignin is synthesized not only during morphogenesis of vascular plants but also in response to various stresses. Isolated Zinnia elegans mesophyll cells can differentiate into tracheary elements (TEs), and deposit lignin into cell walls in TE-inductive medium (D medium). Meanwhile isolated mesophyll cells cultured in hormone-free medium (Co medium) accumulate stress lignin-like substance during culture. Therefore this culture system is suitable for study of lignin and lignin-like substance formation.In D medium lignin was deposited in TEs, but in Co medium, extracellular lignin-like substance accumulated. Analysis of the culture media indicated the presence of dilignols in D culture, but not in Co culture. To investigate the fate of lignin precursors, we added coniferyl alcohol (CA) in each culture. In Co medium, CA was polymerized into dilignols rapidly but they were present only temporarily, and in D medium CA was polymerized into dilignols relatively slowly but their content increased continually.Meanwhile, in Co culture, peroxidase activity in the medium was much higher than the peroxidase activity bound ionically to the cell walls. In D culture, ionically bound peroxidase activity was higher than that in the medium. These results may suggest that lignin deposition in TEs is related to ionically bound peroxidases in D culture, and lignin-like substance deposition in the medium is related to peroxidases in the medium in Co culture.

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