Mitochondrial membranes lipid phase

Hackenbrock CR, Hochh M, Chan RM. Calorimetric and freeze fractnre analysis of lipid phase transitions and lateral translational motion of intramembrane particles in mitochondrial membranes. Biochim. Biophys. Acta 1976 455 466 84. 

Madden TD, Vigo C, Bmckdorfer KR, Chapman D. The incorporation of cholesterol into mitochondrial membranes and its effect on lipid phase transition. Biochim. Biophys. Acta 1980 599 528-537. 

Whereas inhibition of chloroplast electron transport has been correlated with binding to a protein(s), the sites and mechanisms through which herbicides interfere with mitochondrial and chloroplast mediated phosphorylations remain to be identified. When lipophilic herbicides partition into the lipid phases of membranes, they could perturb lipid-lipid, lipid-protein, and protein-protein interactions that are required for membrane functions such as electron transport, ATP formation, and active transport. Evidence for general membrane perturbations caused by chlorpropham, 2,6-dinitroanilines, perfluidone, and certain phenylureas have been reported previously (8-11). 

Apart from the protein matrix, where it is possible for protons to move effectively in keeping with a mechanism somewhat similar to that proposed for the motion of protons in ice there is another path for protons through hydrophobic barrier of which the membrane is an example. This transition is based on the observations of phase transitions in a bilayer by X-ray diffraction methods. In this mechanism developed for mitochondria the main role falls to cardiolipin, which accounts for 33% of the total amount of lipids in the mitochondrial membrane.146 The protonation of the head groups of cardiolipin contained in the membranes of mitochondria caused a phase transition of the bilayer into an inverted hexagonal phase.147 This process is promoted by calcium ions whose reactions with the head groups of lipids favor neutralization of the membrane charge and effective dehydration of the polar heads. 

Thus, under condition of IW, MF decreased the intensity of LPO in mitochondrial membranes. As a result, the pool of unsaturated fatty acids containing 18 and 20 carbon atoms in the lipid phase of mitochondrial membranes remained unchanged. The prevention of changes in fatty acid composition of mitochondrial membranes affected the bioenergetic indices there was maintained a high activity of the NADH-dehydro-genase complex of the respiratory chain of mitochondria. 

NAD-dependent substrate oxidation. At the same time, mitoehondria of storage organs and seeds ate eharaeterized by relatively low rates of oxidation of NAD-dependent substrates. The result of maintenance high activity of NAD-dependent dehydrogenases is the support the energy processes in cell that promotes the resistance of plant to varying envirorunental conditions. Under conditions of IW, protective effect of MF is apparently determined by maintenance in the content of unsaturated fatly acids with 18 and 20 carbon atoms in lipid phase of mitochondrial membranes. 

From the experimental point of view it was shown that, in mice to which aqueous solutions of trecresan and mival (5 mg/L) were administered for 20 days, DNA and RNA content in live animals rose to 110.5 and 134.2 respectively against 98.6 in the test group. Use of trecresan in the partial hepatoectomy experiments in rats results in intensification of hepatocyte regeneration, a rise in macroergons and acceleration of individual phases of the mitotic cycle. These processes occur simultaneously with suppression of lipid peroxide oxidation in the hepatocytes and a decrease in oxygen transfer rate through mitochondrial membranes. Similar tests for the analysis of the... 

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