GSH Solution Research Articles

Reduction of hexavalent chromium by ascorbic acid and glutathione with special reference to the rat lung

The reduction of 20 microM hexavalent chromium [chromium(VI)] by L-ascorbic acid (AsA) (0.06-2 mM) and/or glutathione (GSH) (2-15 mM) in buffer solutions, cell-free bronchoalveolar lavage fluids or soluble fractions of rat lungs was investigated at physiological pH (37 degrees C). The reduction in AsA solution was pseudo-first-order in a single phase with respect to chromium(VI), but that in GSH solution showed a two-phase process. The half-life of chromium(IV) ranged from seconds to hours. The reducing ability of AsA was markedly higher than that of GSH. Coexistence of equimolar GSH with AsA accelerated the reduction rate slightly, in comparison with that in the corresponding AsA solution. Lavage fluids containing 0.06 mM AsA showed pH-dependent reactions similar to those of the corresponding AsA solutions. The lung-soluble fractions reduced chromium(VI) in a process composed of phase I and phase II, characterized by the reducing ability of AsA-GSH cooperation and of AsA alone, respectively. Reduction in the former was 30-40% more rapid than in the latter. The biological half-life of chromium(VI) in the lung was estimated to be 0.6 min, on the basis of the reducing activity in the first phase. However, the apparent biological half-life of chromium(VI) was about 2 min in rat lungs after intratracheal injection of chromate, involving depletion of AsA, but no significant changes in GSH. The difference is discussed in terms of AsA-induced initiative reduction in the alveolar lining fluid and subsequent obstructive effects of the resulting trivalent species on trans-membrane permeability of chromate anions.(ABSTRACT TRUNCATED AT 250 WORDS)

Synergism of ascorbic acid and glutathione in the reduction of hexavalent chromium in vitro.

The reduction of 20 microM hexavalent chromium [chromium(VI)] in single-reductant solutions of 0.02-2 mM L-ascorbic acid (L-AsA) or 2 mM reduced glutathione (GSH), and in mixed solutions of 2 mM GSH containing L-AsA of the above-described concentrations was investigated at physiological pH (37 degrees C). The reduction of chromium(VI) in the L-AsA solutions of higher concentrations showed pseudo-first-order kinetics in a single phase with respect to chromium(VI). In the lower L-AsA concentrations, pseudo-first-order processes appeared only in an early stage of the reaction. The reduction in the GSH solution was characterized by a two-phase process. In the first phase, which appeared in very short duration, the reaction rate was much higher than that in the second, but resulted in a decrease of only 7% of the initial chromium(VI) level. The second phase showed the main process of the reduction. This indicated pseudo-first-order kinetics. The half-life values of chromium(VI) depended on the initial levels of the reductants and ranged from seconds to hours. The chromium(VI)-reducing ability of L-AsA was markedly higher than that of GSH. In the mixed solutions of L-AsA and GSH, synergistic effect on the reduction of chromium(VI) was observed, especially in earlier stages of the processes. The synergism was more conspicuous in the mixed solutions containing lower L-AsA levels. These results suggest that although AsA possesses higher reducing ability than GSH, their coexistence is of importance for the reduction of chromium(VI) in biological systems because of their synergism.

グルタチオンの安定性に及ぼす微量元素の影響と安定化

Glutathione (GSH) was combined with trace elements in infusion solution for total parenteral nutrition.The effects of the trace elements (copper, zinc and selenium) on the stability of GSH, and the stabilization of GSH by protamine sulfate (PT) and ascorbic acid (AC) were studied by reversed-phase high-perfomance liquid chromatography using 4-(amino-sulfonyl)-7-fluoro-2, 1, 3-benzoxadiazole (ABD-F).The contents of GSH decreased in the presence of zinc, copper, and selenium, in that order.In particular, 14%of GSH remained after 10 minutes at 25°Cin the presence of 5μM of selenium.The contents of GSH decreased with an increase in the concentration of selenium.GSH was stabilized by PT or AC in the presence of trace element.When 5μM of cupric sulfate was added to the GSH solution after 20 minutes, 39.5% of GSH remained.On the other hand, 70.6% of GSH remained under the same conditions in the presence of 10mg of AC per ml.

Redox modification of sodium-calcium exchange activity in cardiac sarcolemmal vesicles.

Na-Ca exchange activity in bovine cardiac sarcolemmal vesicles was stimulated up to 10-fold by preincubating the vesicles with 1 microM FeSO4 plus 1 mM dithiothreitol (DTT) in a NaCl medium. The increase in activity was not reversed upon removing the Fe and DTT. Stimulation of exchange activity under these conditions was completely blocked by 0.1 mM EDTA or o-phenanthroline; this suggests that the production of reduced oxygen species (H2O2, O2-.,.OH) during Fecatalyzed DTT oxidation might be involved in stimulating exchange activity. In agreement with this hypothesis, the increase in exchange activity in the presence of Fe-DTT was inhibited 80% by anaerobiosis and 60% by catalase. H2O2 (0.1 mM) potentiated the stimulation of Na-Ca exchange by Fe-DTT under both aerobic and anaerobic conditions; H2O2 also produced an increase in activity in the presence of either FeSO4 (1 microM) or DTT (1 mM), but it had no effect on activity by itself. Superoxide dismutase did not block the effects of Fe-DTT on exchange activity; however, the generation of O2-. by xanthine oxidase in the presence of an oxidizable substrate stimulated activity more than 2-fold. Hydroxyl radical scavenging agents (mannitol, sodium formate, sodium benzoate) did not attenuate the stimulation of activity observed with Fe-H2O2. Exchange activity was also stimulated by the simultaneous presence of glutathione (GSH; 1-2 mM) and glutathione disulfide (GSSG; 1-2 mM). Neither GSH nor GSSG was effective by itself and either 0.1 mM EDTA or o-phenanthroline blocked the effects on transport activity of the combination of GSH + GSSG. Treatment of the GSH and GSSG solutions with Chelex ion-exchange resin to remove contaminating transition metal ions reduced (by 40%) the degree of stimulation observed with GSH + GSSG. Full stimulating activity was restored to the Chelex-treated GSH and GSSG solutions by the addition of 1 microM Fe2+; Cu2+ was less effective than Fe2+ whereas Co2+ and Mn2+ were without effect. In the presence of 1 microM Fe2+, GSH alone produced a slight increase in transport activity, but this was markedly enhanced by the addition of Chelex-treated GSSG. The results indicate that stimulation of exchange activity requires the presence of both a reducing agent (DTT, GSH, O-.2, or Fe2+) and an oxidizing agent (H2O2, GSSG, and perhaps O2) and that the effects of these agents are mediated by metal ions (e.g. Fe2+).(ABSTRACT TRUNCATED AT 400 WORDS)

In vitro propagation of some olive ( Olea europaea sativa L.) cultivars with different root-ability, and medium development using analytical data from developing shoots and embryos

Short- and long-term objectives for research on tissue culture of the olive are described. Sterile shoots were obtained from single-node woody explants or buds of 3 olive cultivars (‘Frantoio’, ‘Dolce Agogia’ and ‘Moraiolo’) with different root-ability, collected from shoots having different degrees of juvenility (suckers, vigorous nonfruit-bearing and fruit-bearing shoots, which are easy, medium and difficult to root, respectively). Because many of the media tested did not give a satisfactory growth rate and good quality shoots, a new medium was formulated by comparing data from analysis of the main mineral elements found in the apical shoots (4–5 mm long) and in mature embryos in olive and almond. Olive tissues were characterized by a high content of Ca, Mg, S, Cu and Zn compared to almond, which is easy to propagate on MS medium. In this newly derived medium, characterized by a high content of these elements, multiplication rate (number of nodes formed per explant) was about 9× in 40 days. The shoots grew more rapidly and were more tender than when grown in other media. Washing of the explants in water or GSH (reduced glutathione) solution, before sub-culturing, improved quality and growth rate of the shoots. Explants, with 2 or 3 nodes, rooted easily in half-strength MS, in Bourgin and Nitsch, or in half Knop macro and Heller microelements, agar media, with 1 mg 1 −1 NAA and 2% sucrose. Rooting was not affected by the different degrees of juvenility of the original explants used. Hardening-off was achieved by growing plants in a 1:1 mixture of perlite and peat-moss in a transparent plastic chamber with saturated circulating air for 1 month. GA 3 sprayed on the leaves was found to be beneficial in stimulating growth resumption of plantlets.

A proton nuclear magnetic resonance study of the interaction of mercury with intact human erythrocytes

The binding of mercuric ion (Hg(II)) by small molecules in the intracellular region of intact human erythrocytes has been studied by 1H-NMR spectroscopy. HgCl 2 added to intact erythrocytes in saline-glucose suspension is found to cross the membrane and reach an equilibrium distribution among the molecules of the erythrocyte within 4 min. In the intracellular region Hg(II) reacts with GSH and hemoglobin to form the ternary mixed-ligand complex GSH-Hg(II)-hemoglobin. The analogous complex with ergothioneine is formed after all the GSH is complexed. 1H-NMR spectra show that the GSH-Hg(II)-hemoglobin complex also forms in simpler solutions containing HgCl 2, GSH and hemoglobin, whereas the complex Hg(GSH) 2 predominates in solutions of GSH and HgCl 2. The lifetime of the GSH in the GSH-Hg(II)-hemoglobin complex is shown to be less than 30 s, which provides direct evidence for the first time that Hg(II) complexes in biological systems are quite labile, even though their thermodynamic stability is large. The effectiveness of eight sulfhydryl-containing ligands, some of which have been used as antidotes for Hg(II) poisoning, for releasing GSH from its Hg(II) complex in hemolyzed erythrocytes was also studied. Dithiol ligands were found to be more effective than monothiols, with dithioerythritol the most effective of the dithiols.

Studies on the interaction of fungicides and plants. 2

In the previous paper, the author concluded that the detoxication of PMA by the rice leaf juice was due to the thiol group present in it. This paper deals with the stoichiometrical reaction of PMA with the known thiol compounds and thiol groups contained in the rice plant.The thiol group was determined by the amperometric titration method, by which SH in the range of 0.03-0.6μM was determined and 96per cent was recovered from glutathione (GSH).The SH contents of egg-albumin, yeast-extract, peptone, γ-globulin were 14.4, 1.23, 0.25, 0.1μM per gram respectively. The detoxication effect varied in this order.In the rice juice, from which protein had been removed, and in the yeast-extract, SH diminished more rapidly than in GSH solution. The SH in the rice juice decreased more slowly during the storage at 5°C than in GSH solution.The SH content was highest in the upper three leaves, about 300μM per 100g fresh weight, decreasing toward the lower leaves. The content was about 1/4 in the leaf still folded and below 1/10 in the leaf sheath, the stem and the root. The SH contents of these tissues varied in parallel with the protein contents. As the stage advanced from the vegetative growth to the reproductive, the SH content in the leaf decreased slowly but the SH became hardly extractable into the juice because of hardening of the tissues.The juice-SH reacted stoichiometrically with PMA at one to one mole ratio. When both PMA and the juice were added to the spore suspension of Cochliobolus miyabeanus, the spore germination was not inhibited until PMA exceeded the equal mole to the juice-SH. The elongation of germ tube was not inhibited until PMA exceeded the half mole of the juice-SH.When PMA dust is applied to the rice plant for the control of blast disease, the amount of PMA deposited on the rice leaves may be at most 1/100-1/1, 000, by mole, to that of SH present in leaves.The author concludes that the effectiveness of PMA for the blast disease is mainly due to the PMA present on the leaf surface or penetrated into the cell membrane, but not due to the PMA penetrated and diffused in the cell sap, because the latter PMA will easily be detoxified by the excessive amount of SH.

LACK OF DEPENDENCE OF THE FEEDING REACTION IN HYDRA ON REDUCED GLUTATHIONE

Previous articleNext article No AccessJournal ArticlesLACK OF DEPENDENCE OF THE FEEDING REACTION IN HYDRA ON REDUCED GLUTATHIONEHELEN FORRESTHELEN FORREST Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 122, Number 3June 1962 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.2307/1539235 Views: 58Total views on this site © 1962 Marine Biological LaboratoryPDF download Crossref reports no articles citing this article.

The production of hydrogen peroxide by high oxygen pressures.

Hydrogen peroxide is formed in solutions of glutathione exposed to oxygen. This hydrogen peroxide or its precursors will decrease the viscosity of polymers like desoxyribonucleic acid and sodium alginate. Further knowledge of the mechanism of these chemical effects of oxygen might further the understanding of the biological effects of oxygen. This study deals with the rate of solution of oxygen and with the decomposition of hydrogen peroxide in chemical systems exposed to high oxygen pressures. At 6 atmospheres, the absorption coefficient for oxygen into water was about 1 cm./hour and at 143 atmospheres, it was about 2 cm./hour; the difference probably being due to the modus operandi. The addition of cobalt (II), manganese (II), nickel (II), or zinc ions in glutathione (GSH) solutions exposed to high oxygen pressure decreased the net formation of hydrogen peroxide and also the reduced glutathione remaining in the solution. Studies on hydrogen peroxide decomposition indicated that these ions act probably by accelerating the hydrogen perioxide oxidation of glutathione. The chelating agent, ethylenediaminetetraacetic acid disodium salt, inhibited the oxidation of GSH exposed to high oxygen pressure for 14 hours. However, indication that oxidation still occurred, though at a much slower rate, was found in experiments lasting 10 weeks. Thiourea decomposed hydrogen peroxide very rapidly. When GSH solutions were exposed to high oxygen pressure, there was oxidation of the GSH, which became relatively smaller with increasing concentrations of GSH.