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An efficient method for the catalytic thiomethylation of regioisomeric aminobenzamides with bis(N,N-dimethylamino)methane (formaldehyde) and H2S (Na2S · 9H2O, NaHS) leading to acyclic S-containing aminobenzamide derivatives or N,S-heterocycles has been developed. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) have caused large challenges in clinical tests and biomedical applications due to their potential toxicity from nanosize effects and heavy metal components. In this study, the physiological responses of Phanerochaete chrysosporium (P. chrysosporium) to CdSe/ZnS QDs with either an inorganic sulfide NaHS or an organic sulfide cysteine as antidote have been investigated. Scanning electron microscope analysis showed that the hyphal structure and morphology of P. chrysosporium have obviously changed after exposure to 100 nM of COOH CdSe/ZnS 505, NH2 CdSe/ZnS 505, NH2 CdSe/ZnS 565, or NH2 CdSe/ZnS 625. Fourier transform infrared spectroscopy analysis indicated that the existence of hydroxyl, amino, and carboxyl groups on cell surface could possibly conduct the stabilization of QDs in an aqueous medium. However, after NaHS or cysteine treatment, the cell viability of P. chrysosporium exposed to CdSe/ZnS QDs increased as compared to control group, since NaHS and cysteine have assisted P. chrysosporium to alleviate oxidative damage by regulating lipid peroxidation and superoxide production. Meanwhile, NaHS and cysteine have also stimulated P. chrysosporium to produce more antioxidant enzymes (superoxide dismutase and catalase), which played significant roles in the defense system. In addition, NaHS and cysteine were used by P. chrysosporium as sulfide sources to promote the glutathione biosynthesis to relieve CdSe/ZnS QDs-induced oxidative stress. This work revealed that sulfide sources (NaHS and cysteine) exerted a strong positive effect in P. chrysosporium against the toxicity induced by CdSe/ZnS QDs. [ABSTRACT FROM AUTHOR]

The subject of study was the Safyanovskaya Med company's acidic underspoil water containing 0.17 g/liter of copper and 1.8 g/liter of zinc (pH 2.8–2.9). The goal was to study and develop a technology of cleaning water of impurities (copper, zinc, aluminum, iron, manganese), accompanied by extraction of copper and zinc in the form of commercial products. Copper extraction by cementation with metallic iron was studied. It was shown that this method could allow extracting 94–95% copper into a concentrate. The role of resolution processes of precipitated copper in cementation was established. To reduce the consumption of iron and to improve the quality of precipitated copper, it is proposed to carry out cementation in a washbox. The copper content in the concentrate was 27–28%, while the specific consumption of iron was 7.0–7.5 kg/kg of copper. During the studies of material composition of copper precipitate, the formation of cuprospinel, goethite, and bassanite phases and the precipitation of basic aluminum sulfates were detected. The extraction of zinc from the solution after copper removal was studied by precipitation with sodium sulfide. As a result, a concentrate was obtained with a zinc content of 49.6–50.9% with extraction of 99%. The process regularities for zinc concentrate dehydration were studied. By optimizing the crystallization conditions of the precipitate, a minimum final cake moisture content of 40–42% was reached. A process flow diagram for acidic underspoil water, including copper cementation and the precipitation of zinc sulfide, was developed. According to this diagram, the mother solution from zinc precipitation should be treated with lime until the pH reaches 10–10.5, followed by slurry settling. As a result, clean water of the following composition is obtained, mg/liter: 0.05 zinc, 0.01 copper, 0.02 aluminum, < 0.02 iron, 0.05 manganese. These values correspond to the quality of drinking water according to GOST R 51232-98. [ABSTRACT FROM AUTHOR]

Erythrocytes change their micromechanical properties associated with membrane viscoelasticity when they perform the transport function. There is some evidence that this is due to the influence of signaling molecules, including such gasotransmitters as nitrogen oxide (NO) and hydrogen sulfide (H2S). The aim of this study was to investigate the changes in microrheology of human erythrocytes under the influence of donors and stimulants of endogenous formation of gasotransmitters. The erythrocyte deformability, assessed by the elongation index of erythrocytes (EIE), and aggregation parameters, the indices of aggregation of erythrocytes (IAE), of washed cells were recorded after their incubation with sodium nitroprusside (SNP); sodium hydrosulfide (NaHS), the donor of H2S; 1H-[1,2,4]-oxadiazolo [4,3-a] quinoxalin-l-one (ODQ), an inhibitor of soluble guanylate cyclase; L-arginine and N-nitroarginine methyl ester (L-NAME), a substrate and an inhibitor of NO synthase, respectively; and glibenclamide (GBC), the blocker of ATP-sensitive potassium channels. In addition, the resealed ghosts of erythrocytes were prepared, incubated with the above compounds, and the change in their deformability was evaluated. EIE increased by 8–11% (p < 0.01) and IAE decreased by 11–26% (p < 0.01) after the incubation of erythrocytes with SNP and NaHS, respectively. L-arginine and SNP exerted similar microrheological effects, which were eliminated by L-NAME or ODQ. GBC caused an increase in EIE by 8% (p < 0.05); the effects of GBC and NaHS were not additive. Incubation of the erythrocyte ghosts with SNP, L-arginine and NaHS was accompanied by a moderate but significant increase in membrane elasticity (p < 0.05). The obtained results indicate that the donors and stimulators of gasotransmitters NO and H2S moderately increase deformability of erythrocytes and markedly reduce their aggregability. The experiments on the erythrocyte ghosts suggest the existence of a direct effect of gasotransmitters on the viscoelastic properties of the membrane of these cells, which is independent of cGMP. [ABSTRACT FROM AUTHOR]

This study investigated the role of hydrogen sulfide (H2S) in the regulation of ascorbateglutathione (AsA-GSH) cycle by exogenous ABA in wheat leaves under osmotic stress. The results showed that osmotic stress significantly increased the activities of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR), the ratio of reduced ascorbate to oxidized ascorbate (AsA/DHA) and reduced glutathione to oxidized glutathione (GSH/GSSG), the malondialdehyde content and electrolyte leakage, and the H2S content, compared to control. Exogenous ABA significantly increased above indicators under osmotic stress, compared to osmotic stress alone. Above activity increases except MDHAR activity were suppressed by application of H2S scavenger hypotaurine (HT) and synthesis inhibitor aminooxyacetic acid (AOA). Meanwhile, exogenous ABA significantly decreased malondialdehyde content and electrolyte leakage induced by osmotic stress. Application of HT and AOA reversed above effects of application of exogenous ABA. Application of NaHS can reversed above effects of HT and AOA. Our results suggested that H2S induced by exogenous ABA is a signal that leads to the up-regulation of AsA-GSH cycle. [ABSTRACT FROM AUTHOR]

Emerging evidence suggests that the gaseous molecules hydrogen sulfide (HS) and nitric oxide (NO) enhances plant acclimation to stress; however, the underlying mechanism remains unclear. In this work, we explored if pretreatment of citrus roots with NaHS (a HS donor) or sodium nitroprusside (SNP, a NO donor) for 2 days (d) could elicit long-lasting priming effects to subsequent exposure to PEG-associated drought stress for 21 d following a 5 d acclimation period. Detailed physiological study documented that both pretreatments primed plants against drought stress. Analysis of the level of nitrite, NOx, S-nitrosoglutahione reductase, Tyr-nitration and S-nitrosylation along with the expression of genes involved in NO-generation suggested that the nitrosative status of leaves and roots was altered by NaHS and SNP. Using a proteomic approach we characterized S-nitrosylated proteins in citrus leaves exposed to chemical treatments, including well known and novel S-nitrosylated targets. Mass spectrometry analysis also enabled the identification of 42 differentially expressed proteins in PEG alone-treated plants. Several PEG-responsive proteins were down-regulated, especially photosynthetic proteins. Finally, the identification of specific proteins that were regulated by NaHS and SNP under PEG conditions provides novel insight into long-term drought priming in plants and in a fruit crop such as citrus in particular. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (HS) plays an important role during rat myocardial injury. However, little is known about the role of HS in hyperhomocysteinemia (HHcy)-induced cardiac dysfunction as well as the underlying mechanisms. In this study, we investigated whether sodium hydrosulfide (NaHS, a HS donor) influences methionine-induced HHcy rat myocardial injury in intact rat hearts and primary neonatal rat cardiomyocytes. HHcy rats were induced by methionine (2.0 g/kg) and the daily administration of 80 μmol/L NaHS in the HHcy + NaHS treatment group. At the end of 4, 8, and 12 weeks, the ultrastructural alterations and functions of the hearts were observed using transmission electron microscopy and echocardiography system. The percentage of apoptotic cardiomyocytes, the mitochondrial membrane potential, and the production of reactive oxygen species (ROS) were measured. The expressions of cystathionine-γ-lyase (CSE), Bax and Bcl-2, caspase-3, phospho-endothelial nitric oxide synthase and the mitochondrial NOX4 and cytochrome c were analyzed by Western blotting. The results showed the cardiac dysfunction, the ultrastructural changes, and the apoptotic rate increase in the HHcy rat hearts. In the primary neonatal rat cardiomyocytes of HHcy group, ROS production was increased markedly, whereas the expression of CSE was decreased. However, treatment with NaHS significantly improved the HHcy rat hearts function, the ultrastructural changes, and decreased the levels of ROS in the primary neonatal rat cardiomyocytes administrated with HHcy group. Furthermore, NaHS down-regulated the expression of mitochondrial NOX4 and caspase-3 and Bax and inhibited the release of cytochrome c from mitochondria. In conclusion, HS is involved in the attenuation of HHcy myocardial injury through the protection of cardiac mitochondria. [ABSTRACT FROM AUTHOR]

Key message: By using pharmacological and molecular approaches, we discovered the involvement of HO-1 in NaHS-induced lateral root formation in tomato seedlings. Abstract: Heme oxygenase-1 (HO-1) and hydrogen sulfide (HS) regulate various responses to abiotic stress and root development, but their involvement in the simultaneous regulation of plant lateral root (LR) formation is poorly understood. In this report, we observed that the exogenously applied HS donor sodium hydrosulfide (NaHS) and the HO-1 inducer hemin induce LR formation in tomato seedlings by triggering intracellular signaling events involving the induction of tomato HO- 1 ( SlHO- 1), and the modulation of cell cycle regulatory genes, including the up-regulation of SlCDKA;1 and SlCYCA2;1, and simultaneous down-regulation of SlKRP2. The response of NaHS in the induction of LR formation was impaired by the potent inhibition of HO-1, which was further blocked when 50 % saturation of carbon monoxide (CO) aqueous solution, one of the catalytic by-products of HO-1, was added. Further molecular evidence revealed that the NaHS-modulated gene expression of cell cycle regulatory genes was sensitive to the inhibition of HO-1 and reversed by cotreatment with CO. The impairment of LR density and length as well as lateral root primordia number, the decreased tomato HO- 1 gene expression and HO activity caused by an HS scavenger hypotaurine were partially rescued by the addition of NaHS, hemin and CO (in particular). Together, these results revealed that at least in our experimental conditions, HO-1 might be involved in NaHS-induced tomato LR formation. Additionally, the use of NaHS and hemin compounds in crop root organogenesis should be explored. [ABSTRACT FROM AUTHOR]

A new symmetrical disulfide containing a diacetylenic unit and bearing a fluorescent carbazolyl end-group forming polymerizable self-assembled monolayers on metallic nanostructures has been synthesized. Suitable modifications of the synthetic steps involved in the synthesis of such derivatives were made in order to assure better synthetic pathway. Conversion of the tosylated derivative into the final symmetrical disulfide is carried out using sodium hydrosulfide (NaSH). [ABSTRACT FROM AUTHOR]

Despite hydrogen sulfide (HS) and nitric oxide (NO) are important endogenous signals or bioregulators involved in many vital aspects of plant growth and responses against abiotic stresses, little information was known about their interaction. In the present study, we evaluated the effects of HS and NO on alfalfa ( Medicago sativa L.) plants exposed to cadmium (Cd) stress. Pretreatment with an HS donor sodium hydrosulfide (NaHS) and well-known NO donor sodium nitroprusside (SNP) decreased the Cd toxicity. This conclusion was supported by the decreases of lipid peroxidation as well as the amelioration of seedling growth inhibition and Cd accumulation, in comparison with the Cd-stressed alone plants. Total activities and corresponding transcripts of antioxidant enzymes, including superoxide dismutase, peroxidase and ascorbate peroxidase were modulated differentially, thus leading to the alleviation of oxidative damage. Effects of HS above were reversed by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (cPTIO), the specific scavenger of NO. By using laser confocal scanning microscope combined with Greiss reagent method, further results showed that NO production increased significantly after the NaHS pretreatment regardless of whether Cd was applied or not, all of which were obviously inhibited by cPTIO. These decreases of NO production were consistent with the exaggerated syndromes associated with Cd toxicity. Together, above results suggested that NO was involved in the NaHS-induced alleviation of Cd toxicity in alfalfa seedlings, and also indicated that there exists a cross-talk between HS and NO responsible for the increased abiotic stress tolerance. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) has been reported to exert pharmacological effects on neural and non-neural tissues from several mammalian species. In the present study, we examined the role of the intracellular messenger, cyclic AMP in retinal response to H2S donors, sodium hydrosulfide (NaHS) and sodium sulfide (Na2S) in cows and pigs. Isolated bovine and porcine neural retinae were incubated in oxygenated Krebs buffer solution prior to exposure to varying concentrations of NaHS, Na2S or the diterpene activator of adenylate cyclase, forskolin. After incubation at different time intervals, tissue homogenates were prepared for cyclic AMP assay using a well established methodology. In isolated bovine and porcine retinae, the combination of both phosphodiesterase inhibitor, IBMX (2 mM) and forskolin (10 μM) produced a synergistic increase ( P < 0.001) in cyclic AMP concentrations over basal levels. NaHS (10 nM–100 μM) produced a time-dependent increase in cyclic AMP concentrations over basal levels which reached a maximum at 20 min in both bovine and porcine retinae. At this time point, both NaHS and Na2S (10 nM–100 μM) caused a significant ( P < 0.05) dose-dependent increase in cyclic AMP levels in bovine and porcine retinae. For instance, NaHS (100 nM) elicited a four-fold and three-fold increase in cyclic AMP concentrations in bovine and porcine retinae respectively whilst higher concentrations of Na2S (100 μM) produced a much lesser effect in both species. In bovine and porcine retinae, the effects caused by forskolin (10 μM) on cyclic AMP production were not potentiated by addition of low or high concentrations of both NaHS and Na2S. We conclude that H2S donors can increase cyclic AMP production in isolated neural retinae from cows and pigs. Bovine retina appears to be more sensitive to the stimulatory effect of H2S donors on cyclic nucleotide production than its porcine counterpart indicating that species differences exist in the magnitude of this response. Furthermore, effects produced by forskolin on cyclic AMP formation were not additive with those elicited by H2S donors suggesting that these agents may share a common mechanism in their action on the adenylyl cyclase pathway. [ABSTRACT FROM AUTHOR]