No abstract

The objectives of this work were to evaluate the direct effects of diallysulfide (DAS) and diallyldisulfide (DADS), two major organosulfur compounds of garlic oil, on mitochondrial function and integrity, by using isolated mouse liver mitochondria in a cell-free system. DADS produced concentration-dependent mitochondrial swelling over the range 125–1000 μM, while DAS was ineffective. Swelling experiments performed with de-energized or energized mitochondria showed similar maximal swelling amplitudes. Cyclosporin A (1 μM), or ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA, 1 mM) were ineffective in inhibiting DADS-induced mitochondrial swelling. DADS produced a minor (12%) decrease in mitochondrial membrane protein thiols, but did not induce clustering of mitochondrial membrane proteins. Incubation of mitochondria with DADS (but not DAS) produced an increase in the oxidation rate of 2′,7′ dichlorofluorescein diacetate (DCFH-DA), together with depletion of reduced glutathione (GSH) and increased lipid peroxidation. DADS (but not DAS) produced a concentration-dependent dissipation of the mitochondrial membrane potential, but did not induce cytochrome c release. DADS-dependent effects, including mitochondrial swelling, DCFH-DA oxidation, lipid peroxidation and loss of mitochondrial membrane potential, were inhibited by antioxidants and iron chelators. These results suggest that DADS causes direct impairment of mitochondrial function as the result of oxidation of the membrane lipid phase initiated by the GSH- and iron-dependent generation of oxidants.

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Tetrahydrofurfuryl methacrylate (THFM) polymerizes at 60 0 C when initiated with potassium persulfate in three-component microemulsions made with Aerosol-OT (AOT) and water. The resulting monodisperse microlatex contains particles with mean diameters from 25 to 34 nm and polymer molecular weights of order 107. Each particle consists of approximately one polymer molecule in a collapsed state. Polymerization kinetics are followed by calorimetry, dilatometry, and internal reflectance infrared spectroscopy. Reaction rate curves show two intervals only: an interval of increasing rate immediately followed by an interval of decreasing rate. Weight-average molecular weight as measured by size-exclusion chromatography and particle size as measured by quasielastic light scattering increase during polymerization. Transmission electron microscopy (TEM) shows the in situ formation of lamellar and multilamellar structures when excess AOT from micelles depleted of monomer exceeds its solubility in water. These findings confirm that latex particles grow by recruiting monomer from uninitiated microemulsion droplets.