diamide and cumene-hydroperoxide

Elemental uptake and export of the cell are tightly regulated thereby maintaining the ionomic homeostasis. This equilibrium can be disrupted upon exposure to exogenous reactive oxygen species (ROS), leading to reduction or elevation of the intracellular metal ions. In this study, the ionomic composition in the eukaryotic model organism Saccharomyces cerevisiae was profiled using the inductively-coupled plasma optical emission spectrometer (ICP-OES) following the treatment with individual ROS, including hydrogen peroxide, cumen hydroperoxide, linoleic acid hydroperoxide (LAH), the superoxide-generating agent menadione, the thiol-oxidising agent diamide [diazine-dicarboxylic acid-bis(dimethylamide)], dimedone and peroxynitrite. The findings demonstrated that different ROS resulted in distinct changes in cellular metal ions. Aluminium (Al(3+)) level rose up to 50-fold after the diamide treatment. Cellular potassium (K(+)) in LAH-treated cells was 26-fold less compared to the non-treated controls. The diamide-induced Al(3+) accumulation was further validated by the enhanced Al(3+) uptake along the time course and diamide doses. Pre-incubation of yeast with individual elements including iron, copper, manganese and magnesium failed to block diamide-induced Al(3+) uptake, suggesting Al(3+)-specific transporters could be involved in Al(3+) uptake. Furthermore, LAH-induced potassium depletion was validated by a rescue experiment in which addition of potassium increased yeast growth in LAH-containing media by 26% compared to LAH alone. Taken together, the data, for the first time, demonstrated the linkage between ionomic profiles and individual oxidative conditions.

Topics: Aluminum; Benzene Derivatives; Copper; Cyclohexanones; Diamide; Hydrogen Peroxide; Ions; Linoleic Acids; Lipid Peroxides; Magnesium; Manganese; Models, Molecular; Oxidants; Oxidative Stress; Peroxynitrous Acid; Potassium; Reactive Oxygen Species; Saccharomyces cerevisiae; Vitamin K 3

Exposure of Agrobacterium tumefaciens to menadione, cumene hydroperoxide, and diamide strongly induced trxA expression. The trxA mutant showed a reduction in the aerobic growth rate and plating efficiency and was cytochrome c oxidase negative. Atypically, the mutant has decreased resistance to menadione but an increased H2O2 resistance phenotype.

Topics: Agrobacterium tumefaciens; Bacterial Proteins; Benzene Derivatives; Diamide; Gene Expression Regulation, Bacterial; Oxidants; Thioredoxins; Vitamin K 3

A Bacillus subtilis sigM null mutant, lacking the extracytoplasmic function sigma(M) protein, was sensitive to paraquat (PQ), a superoxide-generating reagent, but not to the redox stress-inducing compounds hydrogen peroxide, cumene hydroperoxide, t-butyl hydroperoxide, or diamide. Surprisingly, a sigM mutant was only sensitive to superoxide-generating compounds with a dipyridyl ring such as PQ, ethyl viologen, benzyl viologen, and diquat but not to menadione, plumbagin, pyrogallol, or nitrofurantoin. Mutational analysis of candidate sigma(M)-regulated genes revealed that both YqjL, a putative hydrolase, and BcrC, a bacitracin resistance protein, were involved in PQ resistance. Expression of yqjL, but not bcrC, from a xylose-inducible promoter restored PQ resistance to the sigM mutant.

Topics: Anti-Bacterial Agents; ATP-Binding Cassette Transporters; Bacillus subtilis; Bacterial Proteins; Benzene Derivatives; Diamide; Diquat; DNA Mutational Analysis; Drug Resistance, Bacterial; Hydrogen Peroxide; Hydrolases; Mutation; Naphthoquinones; Nitrofurantoin; Paraquat; Pyrogallol; Sigma Factor; tert-Butylhydroperoxide; Viologens; Vitamin K 3

The different mechanisms for glutathione-dependent inactivation of a number of oxidizing compounds and other xenobiotics were studied using isolated round spermatids from rats. For the estimation of cellular GSH a flow cytometric assay was used. The cells were exposed to the oxidizing compounds cumene hydroperoxide and diamide, to study the activity of the GSH redox cycle. Incubation of the isolated cells with these compounds showed that the cells had a limited capacity to withstand the oxidative stress associated with their inactivation. The GSH level of the spermatids was maintained during 18 h of incubation in the presence of low concentrations of cumene hydroperoxide and diamide, whereas spermatids exposed to higher concentrations showed a loss of both GSH and ATP. No partial loss of GSH from individual cells was observed. Diethyl maleate and 1,2-epoxy-p-(nitrophenoxy)propane (ENPP) were used to study the effect of glutathione S-transferase-catalysed GSH conjugation on the GSH content of spermatids. Exposure of the cells to low concentrations of diethyl maleate and ENPP resulted in a decrease in GSH content. The flow cytometric analysis showed that this was a partial loss of GSH from all cells, rather than GSH depletion in a part of the cell population. This diminution of the cellular GSH pool, however, did not affect the ATP content and viability of the cells. The present results indicate that spermatids can utilize GSH-dependent defence mechanisms against a number of model compounds.

Topics: Adenosine Triphosphate; Animals; Benzene Derivatives; Diamide; Glutathione; Glutathione Transferase; Inactivation, Metabolic; Male; NADH, NADPH Oxidoreductases; Pentose Phosphate Pathway; Rats; Rats, Inbred Strains; Sertoli Cells; Spermatids; Spermatocytes; Testis; Xenobiotics

lipid peroxidation was initiated and facilitated in isolated adult heart cells by treating the cells with different concentrations of either diamide or cumene hydroperoxide. Both reagents can lower the cellular level of reduced glutathione, diamide, by oxidizing preferentially the -SH groups and cumene hydroperoxide by acting as a substrate for glutathione peroxidase and/or initiating lipid peroxidation. Examination by electron microscopy revealed that 2 x 10(-4) diamide or 0.1 mM cumene induced severe ultrastructural changes within 1 hour of treatment. The most prominent changes were contraction, severe blebbing of the plasma membrane, and the presence of mitochondrial inclusions. A severe decline in intracellular ATP accompanied these ultrastructural changes. Diene conjugation, as an index of lipid peroxidation, demonstrated that peroxidation of cellular lipids did not occur in all cell samples treated (diamide greater than cumene). Treatment of these cells with lipid peroxides produced enzymatically in liver microsome membranes gave additional confirmation that heart cells are particularly sensitive to this treatment and that lipid peroxidation could have an important role in myocardial damage.

Topics: Adenosine Triphosphate; Animals; Azo Compounds; Benzene Derivatives; Diamide; Heart; Lipid Metabolism; Male; Microscopy, Electron; Microscopy, Fluorescence; Microsomes; Microsomes, Liver; Mitochondria, Heart; Myocardium; Rats