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Soluble Antioxidants (soluble + antioxidant)
Selected AbstractsInfluence of the SCGE protocol on the amount of basal DNA damage detected in the Mediterranean mussel, Mytilus galloprovincialisENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 8 2006Nicola Machella Abstract Genotoxicity studies using the single cell gel electrophoresis (SCGE) assay indicate that basal levels of DNA strand breaks (SBs) in marine invertebrates are higher and more variable than those in marine vertebrates. This elevated level of DNA damage was attributed to a large number of alkali-labile sites, which are characteristic of the tightly-packaged DNA in invertebrate cells. To investigate if altering the SCGE protocol can artificially modulate high levels of SBs, SCGE experiments were performed on haemocytes from the Mediterranean mussel (Mytilus galloprovincialis) using proteinase K (PK) digestion in combination with assay buffers containing various concentrations of EDTA. In addition, the effects of Trolox® (soluble antioxidant) and aurintricarboxylic acid (ATA; inhibitor of Ca2+/Mg2+ -dependent nucleases) also were tested. The levels of SBs in M. galloprovicialis cells were compared with SBs in cells from a terrestrial mollusk (the snail Helix aspersa), and a teleost fish (the seabass Dicentrarchus labrax). The integrity of M. galloprovincialis DNA isolated with phenol extractions using EDTA, Trolox, and ATA was further assayed by gel electrophoresis. High SBs in mussel cells were reduced by combining EDTA with PK digestion, or using Trolox® or ATA during cell processing for the SCGE assay. Snails and seabass had lower levels of SBs in the SCGE assay, and the levels were not affected by the protocol modifications. Adding EDTA, Trolox®, or ATA to phenol extractions of M. galloprovincialis genomic DNA also reduced the extent of DNA fragmentation. These results suggest that the internal fluids of M. galloprovincialis may increase the basal levels of DNA SBs through oxidative and/or enzyme-mediated pathways. M. galloprovincialis is used extensively as a sentinel species for assessing the genotoxic hazard of marine pollutants. Our data suggest that the SCGE protocol should be carefully considered when assessing DNA damage in these species. Environ. Mol. Mutagen., 2006. © 2006 Wiley-Liss, Inc. [source] Nanoparticle formation of organic compounds with retained biological activityJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 6 2010Gunilla B. Jacobson Abstract Many pharmaceuticals are formulated as powders to aid drug delivery. A major problem is how to produce powders having high purity, controlled morphology, and retained bioactivity. We demonstrate the use of supercritical carbon dioxide as an antisolvent for meeting this need for two model drug systems, quercetin, a sparingly soluble antioxidant, and short interfering RNA (siRNA), which can silence genes. In both cases we achieve retention of bioactivity as well as a narrow particle size distribution in which the particles are free of impurities. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 2750,2755, 2010 [source] Current Opinions on the Functions of Tocopherol Based on the Genetic Manipulation of Tocopherol Biosynthesis in PlantsJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 9 2008Yin Li Abstract As a member of an important group of lipid soluble antioxidants, tocopherols play a paramount role in the daily diet of humans and animals. Recently, genes required for tocochromanol biosynthesis pathway have been identified and cloned with the help of genomics-based approaches and molecular manipulation in the model organisms: Arabidopsis thaliana and Synechocystis sp. PCC 6803. At the basis of these foundations, genetic manipulation of tocochromanol biosynthesis pathway can give rise to strategies that enhance the level of tocochromanol content or convert the constitution of tocochromanol. In addition, genetic manipulations of the tocochromanol biosynthesis pathway provide help for the study of the function of tocopherol in plant systems. The present article summarizes recent advances and pays special attention to the functions of tocopherol in plants. The roles of tocopherol in the network of reactive oxygen species, antioxidants and phytohormones to maintain redox homeostasis and the functions of tocopherol as a signal molecule in chloroplast-to-nucleus signaling to regulate carbohydrate metabolism are also discussed. [source] Photobleaching of Melanosomes from Retinal Pigment Epithelium: I. Effects on Protein OxidationPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2007Janice M. Burke ABSTRACT Melanin in the long-lived melanosomes of the retinal pigment epithelium (RPE) may undergo photobleaching with aging, which appears to diminish the antioxidant function of melanin and could make photobleached melanosomes less efficient in protecting biomolecules from oxidative modification. Here we analyzed whether photobleaching of melanosomes affects their ability to modify the oxidation state of nearby protein. As conventional methods developed to study soluble antioxidants are not well suited for analysis of granules such as melanosomes, we developed a new analytic method to focus on particle surfaces that involves experimentally coating granules with the cytoskeletal protein ,-actin to serve as a reporter for local protein oxidation. Isolated porcine RPE melanosomes were photobleached with visible light to simulate aging, then photobleached melanosomes, untreated melanosomes and control particles (black latex beads) were actin coated and illuminated in a photosensitized cell free system. Protein was re-stripped from particles and analyzed for carbonylation by Western blotting. Quantitative densitometry showed no reproducible differences for protein associated with untreated melanosomes when compared with control particles. Melanin has both anti- and pro-oxidant functions when light irradiated, but neither of these functions predominated in the protein oxidation assay when untreated melanosomes were used. However, protein extracted from photobleached melanosomes showed markedly increased carbonylation, both of associated actin and of endogenous melanosomal protein(s), and the effect increased with extent of granule photobleaching. Photobleaching of RPE melanosomes therefore changes the oxidation state of protein endogenous to the organelle and reduces the ability of the granule to modify the oxidation of exogenous protein near the particle surface. The results support the growing body of evidence that photobleaching of RPE melanosomes, which is believed to occur with aging, changes the physicochemical properties of the organelle and reduces the likelihood that the granules perform an antioxidant function. [source] Prospects for enhancement of the soluble antioxidants, ascorbate and glutathioneBIOFACTORS, Issue 2-4 2001Christine H. Foyer Ascorbic acid (vitamin C) and the tripeptide thiol, glutathione , -glutamyl cysteinyl glycine (glutathione) are the major low molecular weight soluble antioxidants in plant cells. The pathway of glutathione biosynthesis is similar in animals and plants while that of ascorbate biosynthesis differs considerably between the two kingdoms. The potential for obtaining substantial constitutive changes in the tissue contents of these antioxidants by manipulation of the biosynthetic enzymes has been demonstrated. Moreover, the concentrations of ascorbate and glutathione are greatly modified in response to a variety of environmental triggers, particularly those that cause increased oxidative stress. It is essential that the signals and associated signal transduction pathways that trigger enhanced antioxidant accumulation are elucidated as these offer an important alternative means of achieving greater nutritional value in edible plant organs. [source] | ||||||||||