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|Title:||Ion Transport Processes in Isolated Corn (Zea Mays L.) Mitochondria (Dibucaine, Methomyl, Phospholipids)|
|Author(s):||Klein, Robert Richard|
|Department / Program:||Agronomy|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||Studies examining the effects of the local anesthetic dibucaine and the effects of Bipolaris maydis (race T) (BmT) toxin on the in vitro ion- and electron-transport activity of corn mitochondria were conducted. In conjunction with these studies was a comparison of the mode of action of BmT toxin and the insecticide methomyl in uncoupling T cytoplasm corn mitochondria. Further, the phospholipid and fatty acid compositions of corn mitochondrial membranes were determined.
The local anesthetic dibucaine inhibited K('+) efflux through blockage of the K('+)/H('+) antiport. Blockage of the K('+)/H('+) antiport is attributable to decreased cation conductance by the inner membrane. Dibucaine further inhibited proton conductance facilitated by the ATPase complex and by protonophores.
BmT toxin and the insecticide methomyl uncouple T mitochondria by decreasing the resistance of the inner membrane to protons and ions. BmT toxin and methomyl induce irreversible swelling and cause the loss of osmotic volume regulation. Direct comparison of the model of action of methomyl and BmT toxin clearly demonstrates that they act in a similar manner.
The phospholipid and fatty acid compositions of corn mitochondrial membranes were determined. Phosphatidylcholine (42%) and phosphatidylethanolamine (39%) were the major phospholipids of the inner membrane. Compared to the inner membrane, the outer mitochondrial membrane contained a higher percentage of phosphatidylcholine (62%) and a lower percentage of phosphatidylethanolamine (21%). Other minor differences in the phospholipid composition of the inner and outer mitochondrial membranes were detected. The inner mitochondrial membrane was characterized by a higher degree of fatty acid unsaturation compared to the outer membrane. Linoleic acid (C(,18:2)) was the major fatty acid (61%) of the inner membrane while palmitic (C(,16:0)) and stearic (C(,18:0)) acids comprised 66% of the fatty acids of the outer membrane.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984.
|Date Available in IDEALS:||2014-12-16|