Hydrogen sulfide reduces oxidative stress in Huntington's disease via Nrf2

The pathophysiology of Huntington's disease involves high levels of the neurotoxin quinolinic acid. Quinolinic acid accumulation results in oxidative stress, which leads to neurotoxicity. However, the molecular and cellular mechanisms by which quinolinic acid contributes to Huntington's disease pathology remain unknown. In this study, we established in vitro and in vivo models of Huntington's disease by administering quinolinic acid to the PC12 neuronal cell line and the striatum of mice, respectively. We observed a decrease in the levels of hydrogen sulfide in both PC12 cells and mouse serum, which was accompanied by down-regulation of cystathionine β-synthase, an enzyme responsible for hydrogen sulfide production. However, treatment with NaHS(a hydrogen sulfide donor) increased hydrogen sulfide levels in the neurons and in mouse serum, as well as cystathionine β-synthase expression in the neurons and the mouse striatum, while also improving oxidative imbalance and mitochondrial dysfunction in PC12 cells and the mouse striatum. These beneficial effects correlated with upregulation of nuclear factor erythroid 2-related factor 2 expression. Finally, treatment with the nuclear factor erythroid 2-related factor 2inhibitor ML385 reversed the beneficial impact of exogenous hydrogen sulfide on quinolinic acid-induced oxidative stress. Taken together, our findings show that hydrogen sulfide reduces oxidative stress in Huntington's disease by activating nuclear factor erythroid 2-related factor 2,suggesting that hydrogen sulfide is a novel neuroprotective drug candidate for treating patients with Huntington's disease.

Defects‑Rich Heterostructures Trigger Strong Polarization Coupling in Sulfides/Carbon Composites with Robust Electromagnetic Wave Absorption

Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies,as well as veiled dielectric-responsive character,are instrumental in electromagnetic dissipation.Conventional methods,however,constrain their delicate constructions.Herein,an innovative alternative is proposed:carrageenan-assistant cations-regulated(CACR)strategy,which induces a series of sulfides nanoparticles rooted in situ on the surface of carbon matrix.This unique configuration originates from strategic vacancy formation energy of sulfides and strong sulfides-carbon support interaction,benefiting the delicate construction of defects-rich heterostructures in M_(x)S_(y)/carbon composites(M-CAs).Impressively,these generated sulfur vacancies are firstly found to strengthen electron accumulation/consumption ability at heterointerfaces and,simultaneously,induct local asymmetry of electronic structure to evoke large dipole moment,ultimately leading to polarization coupling,i.e.,defect-type interfacial polarization.Such“Janus effect”(Janus effect means versatility,as in the Greek two-headed Janus)of interfacial sulfur vacancies is intuitively confirmed by both theoretical and experimental investigations for the first time.Consequently,the sulfur vacancies-rich heterostructured Co/Ni-CAs displays broad absorption bandwidth of 6.76 GHz at only 1.8 mm,compared to sulfur vacancies-free CAs without any dielectric response.Harnessing defects-rich heterostructures,this one-pot CACR strategy may steer the design and development of advanced nanomaterials,boosting functionality across diverse application domains beyond electromagnetic response.

Absorption characteristics,model,and molecular mechanism of hydrogen sulfide in morpholine acetate aqueous solution

The solubility of H_(2)S was measured in solutions of N-butyl-N-methylmorpholine acetate([Bmmorp][Ac])containing 20%-40%(mass)water at experimental temperatures ranged from 298.15 to 328.15 K and pressures up to 320 k Pa.The total solubility of H_(2)S increased with higher temperatures,lower pressures,and reduced water content.The reaction equilibrium thermodynamic model was used to correlate the solubility data.The results indicate that the chemical reaction equilibrium constant decrease with increasing water content and temperature,whereas Henry constant increase with increasing water content and temperature.Compared with other ionic liquids,H_(2)S exhibits a higher physical absorption enthalpy and a lower chemical absorption enthalpy in[Bmmorp][Ac]aqueous solution.This suggests that[Bmmorp][Ac]has a strong physical affinity for H_(2)S and low energy requirement for desorption.Quantum chemical methods were used to investigate the molecular mechanism of H_(2)S absorption in ionic liquids.The interaction energy analysis revealed that the binding of H_(2)S with the ionic liquid in a1:2 ratio is more stable.Detailed analyses by the methods of the interaction region indicator and the atoms in molecules were conducted to the interactions between H_(2)S and the ionic liquid.

Hydrogen sulfide responsive nanoplatforms: Novel gas responsive drug delivery carriers for biomedical applications

Hydrogen sulfide(H_(2)S)is a toxic,essential gas used in various biological and physical processes and has been the subject of many targeted studies on its role as a new gas transmitter.These studies have mainly focused on the production and pharmacological side effects caused by H_(2)S.Therefore,effective strategies to remove H_(2)S has become a key research topic.Furthermore,the development of novel nanoplatforms has provided new tools for the targeted removal of H_(2)S.This paper was performed to review the association between H_(2)S anddisease,relatedH_(2)S inhibitory drugs,aswell as H_(2)S responsive nanoplatforms(HRNs).This review first analyzed the role of H_(2)S in multiple tissues and conditions.Second,common drugs used to eliminate H_(2)S,as well as their potential for combination with anticancer agents,were summarized.Not only the existing studies on HRNs,but also the inhibition H_(2)S combined with different therapeutic methods were both sorted out in this review.Furthermore,this review provided in-depth analysis of the potential of HRNs about treatment or detection in detail.Finally,potential challenges of HRNs were proposed.This study demonstrates the excellent potential of HRNs for biomedical applications.

Synthesis of High Purity Lithium Sulfide for Sulfide Solid Electrolyte Applications through Hydrogen Reduction of Lithium Sulfate

This paper is aimed to present a clean,inexpensive and sustainable method to synthesize high purity lithium sulfide(Li_(2)S)powder through hydrogen reduction of lithium sulfate(Li_(2)SO_(4)).A three-step reduction process has been successfully developed to synthesize well-crystallized and single-phase Li_(2)S powder by investigating the melting,sintering and reduction behavior of the mixtures of Li_(2)SO_(4)-Li_(2)S.High purity alumina was found to be the most suitable crucible material for producing high purity Li_(2)S,because it was not attacked by the Li_(2)SO_(4)-Li_(2)S melt during heating,as compared with other materials,such as carbon,mullite,quartz,boron nitride and stainless steel.The use of synthesized LizS resulted in higher purity and substantially higher room temperature ionic conductivity(2.77 mS·cm^(-1))for the argyrodite sulfide electrolyte Li_(6)PS_(5)Cl than commercial Li_(2)S(1.12 mS·cm^(-1)).This novel method offers a great opportunity to produce battery grade Li_(2)S for sulfide solid electrolyte applications.

Comparative study on the hydrogen storage performance of as-milled MgRENi rapid quenched alloy catalyzed by metal sulfides

The composites of Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)as-quenched alloy and 3 wt.%M(M=CoS,CoS_(2),MoS_(2))catalyst were prepared by high-speed vibration ball mill.The effects of metal sulfides on the hydrogenation and dehydrogenation dynamics of alloys were compared.The results show that the as-milled composites contain a large number of amorphous embedded by a small amount of nanocrystals,and there are many point defects.After ball milling,the crystal grain size in the composites containing CoS is relatively larger,followed by CoS_(2)and MoS_(2)again.After hydrogenation,the amorphous phase is crystallized to form Mg_(2)NiH_(4),YH_(3),Pr_(8)H_(18.96),Sm_(3)H_7,Mg,Co or Mo phases,however,Mg_(2)Ni,YH_(2),PrH_(2)and Ni_(3)Y phases appeared after dehydrogenation.The maximum hydrogenation capacity of the composites containing CoS,CoS_(2)and MoS_(2)are 3.939,4.265 and 4.507 wt.%,respectively.The hydrogenation saturation ratio of composite containing MoS_(2)is higher than that of the composites containing CoS and CoS_(2).The dehydrogenation activation energy of the composites containing CoS,CoS_(2)and MoS_(2)is 107.76,68.43 and 63.28 kJ.mol^(-1).H_(2).On the improvement of hydrogen storage performance of Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)alloy,the catalytic effect of MoS_(2)sulfide is better than that of CoS_(2)sulfide,and which is better than CoS sulfide.

Effect of Exogenous Hydrogen Sulfide(H_2S) on the Electrocardiogram(ECG) of Rats Generally Anaesthetized by Zoletil

Hydrogen sulfide （H2S） is the third gaseous signaling molecule discovered in recent years, and plays an important physiological role in the cardivascular system. To explore the effects of different doses of exogenous H2S on the electrocardiogram （ECG） of rats generally anesthetized by zoletil, different doses of NariS solution were used for the intervention of intraperitoneal injection 20 rain before the zoletil anesthesia. The ECGs of rats from each treatment group during the time range of 10^th-50^th min were determined under general anesthesia, and then were compared with those from the control group. The results showed that exogenous H2S could significantly reduce the Q-T interval time limit, thus played a role in slowing tachycardia or arrhythmia and other anomalies, thereby protecting the heart. S-T segment and T segment evaluation values were significantly reduced, which might be associated with bradycardia.

Research Development of Control Technology of Hydrogen Sulfide in Biogas Slurry

In order to provide help for the accurate application of biogas slurry in the field, the application of biogas slurry and control technology of hydrogen sulfide in biogas slurry were reviewed. Results of recent researches suggested that source control and end-treatment were the two measures to remove hydrogen sulfide in biogas slurry, including physical method, chemical method and biological method. Some conventional deodorizing methods were introduced and compared.

Hydrogen Sulfide May Function Downstream of Nitric Oxide in Ethylene-Induced Stomatal Closure in Vicia faba L.

Pharmacological, laser scanning confocal microscopic （LSCM）, and spectrophotographic approaches were used to study the roles of hydrogen sulfide （H2S） and nitric oxide （NO） in signaling transduction of stomatal movement in response to ethylene in Viciafaba L. Ethylene treatment resulted in the dose-dependent stomatal closure under light, and this effect was blocked by the inhibitors of H2S biosynthesis in V. faba L. Additionally, ethylene induces H2S generation and increases L-/D-cysteine desulfhydrase （pyridoxalphosphate-dependent enzyme） activity in leaves of V. faba L. Inhibitors of H2S biosynthesis have no effect on the ethylene-induced stomatal closure, NO accumulation, and nitrate reductase （NR） activity in guard cells or leaves of II. faba L. Moreover, the ethylene-induced increase of H2S levels and L-/D- cysteine desulfhydrase activity declined when NO generation was inhibited. Therefore, we conclude that H2S and NO probably are involved in the signal transduction pathway of ethylene-induced stomatal closure. H2S may represent a novel component downstream of NO in the ethylene-induced stomatal movement in V. faba L.

Reactions of Group V Metal Atoms with Hydrogen Sulfide： Argon Matrix Infrared Spectra and Theoretical Calculations

The reaction of laser-ablated vanadium, niobium and tantalum atoms with hydrogen sulfide has been investigated using matrix isolation FTIR and theoretical calculations. The metal atoms inserted into the H-S bond of H2S to form the HMSH molecules （M=V, Nb, Ta）, which rearranged to H2MS molecules on annealing for Nb and Ta. The HMSH molecule can also further react with another H2S to form the H2M（SH）2 molecules. These new molecules were identified on the basis of the D2S and H234S isotopic substitutions. DFT （B3LYP and BPW91） theoretical calculations are used to predict energies, geometries, and vibrational frequencies for these novel metal dihydrido complexes and molecules. Reaction mechanism for formation of group V dihydrido complex was investigated by DFT internal reaction coordinate calculations. The dissociation of HVSH gave VS＋H2 on broad band irradiation and reverse reaction happened on annealing. Based on B3LYP calculation releasing hydrogen from HVSH is endothermic only by 13.5 kcal/mol with lower energy barrier of 16.9 kcal/mol.

Studies on the Tolerating Mechanism for Sulfide in Urechis unicinctus (Echiura: Urechidae) ──Cytological Observation on Urechis unicinctus in Different Hydrogen Sulfide Environment

This study on the cytological changes of the body wall,aspiratory intestine and crissal bursa in Urechis unicinctus by light microscope (LM) and transmission electron microscope (TEM) showed that the difference between the body wall and the natural environment rich in H 2S was not obvious; that the wall color of the aspiratory intestine in H 2S rich environment changed from normal semitransparency to dark brown; that its epithelia were disassembled and the electron density of its cytoplasm matrix was lower; and that in H 2S rich environment many basophilic granules occurred in the epithelia of the crissal bursa. Granules with single membrane and myelinefingure were found with TEM.

Hydrogen sulfide enhances adult neurogenesis in a mouse model of Parkinson's disease

Hydrogen sulfide(H_2S) is regarded to be a protectant against diseases of the central nervous system and cardiovascular system.However, the mechanism by which H_2S elicits neuroprotective effects in the progression of Parkinson's disease(PD) remains unclear.To investigate the role of H_2S in delaying the pathological process of PD, we used the most common sodium hydrosulfide(Na HS) as an H_2S donor and established a mouse model of PD induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid(MPTP/p) in the present study.Our results show that H_2S reduced neuronal loss during the progression of PD.Notably, we found that H_2S exhibited protective effects on dopaminergic neurons.Excitingly, H_2S also increased the proliferation of neural stem cells in the subventricular zone.Next, we evaluated whether the neuroprotective effects of H_2S on dopaminergic neurons in PD are dependent on adult nerve regeneration by treating primary adult neural stem cells cultured ex vivo with 1-methyl-4-phenylpyridine.Our results show that H_2S could prevent nerve injury induced by 1-methyl-4-phenylpyridine, promote the growth of neurospheres, and promote neurogenesis by regulating Akt/glycogen synthase kinase-3β/β-catenin pathways in adult neural stem cells.These findings confirm that H_2S can increase neurogenesis in an adult mouse model of PD by regulating the Akt/glycogen synthase kinase-3β/β-catenin signaling pathway.This study was approved by the Animal Care and Use Committee of Nanjing Medical University, China(IACUC Approval No.1601153-3).

Bile-acid-activated farnesoid X receptor regulates hydrogen sulfide production and hepatic microcirculation

AIM: To investigate whether the farnesoid X receptor (FXR) regulates expression of liver cystathionase (CSE), a gene involved in hydrogen sulfi de (H2S) generation. METHODS: The regulation of CSE expression in response to FXR ligands was evaluated in HepG2 cells and in wild-type and FXR null mice treated with 6-ethyl chenodeoxycholic acid (6E-CDCA), a synthetic FXR ligand. The analysis demonstrated an FXR responsive element in the 5'-flanking region of the human CSE gene. The function of this site was investigated by luciferase reporter assays, chromatin immunoprecipitation and electrophoretic mobility shift assays. Livers obtained from rats treated with carbon tetrachloride alone, or in combination with 6-ethyl chenodeoxycholic acid, were studied for hydrogen sulphide generation and portal pressure measurement. RESULTS: Liver expression of CSE is regulated by bile acids by means of an FXR-mediated mechanism. Western blotting, qualitative and quantitative polymerase chain reaction, as well as immunohistochemical analysis, showed that expression of CSE in HepG2 cells and in mice is induced by treatment with an FXR ligand. Administration of 6E-CDCA to carbon tetrachloride treated rats protected against the down-regulation of CSE expression, increased H2S generation, reduced portal pressure and attenuated the endothelial dysfunction of isolated and perfused cirrhotic rat livers. CONCLUSION: These results demonstrate that CSE is an FXR-regulated gene and provide a new molecular explanation for the pathophysiology of portal hypertension.

Hydrogen sulfide protects against amyloid beta-peptide induced neuronal injury via attenuating inflammatory responses in a rat model

Neuroinflammation has been recognized to play a critical role in the pathogenesis of Alzheimer＇s disease （AD）, which is pathologically characterized by the accumulation of senile plaques containing activated microglia and amyloid β-peptides （Aβ）. In the present study, we examined the neuroprotective effects of hydrogen sulfide （H2S） on neuroinflammation in rats with Aβ1-40 hippocampal injection. We found that Aβ-induced rats exhibited a disorder of pyramidal cell layer arrangement, and a decrease of mean pyramidal cell number in the CA1 hippocampal region compared with those in sham operated rats. NaHS （a donor of H2S, 5.6 mg/kg/d, i.p.） treatment for 3 weeks rescued neuronal cell death significantly. Moreover, we found that H2S dramatically suppressed the release of TNF-α, IL-1β and IL-6 in the hippocampus. Consistently, both immunohistochemistry and Western blotting assays showed that H2S inhibited the upregulation of COX-2 and the activation of NF-κB in the hippocampus. In conclusion, our data indicate that H2S suppresses neuroinflammation via inhibition of the NF-κB activation pathway in the Aβ-induced rat model and has potential value for AD therapy.

Kinetics of hydrogen sulfide decomposition in a DBD plasma reactor operated at high temperature

The present study investigates the kinetics of hydrogen sulfide （H2S） decomposition into hydrogen and sulfur carded out in a nonthermal plasma dielectric barrier discharge （NTP-DBD） reactor operated at ,-430 K for in situ removal of sulfur condensed inside the reactor walls. The dissociation of H2S was primarily initiated by the excitation of carder gas （At） through electron collisions which appeared to be the rate determining step. The experiments were carded out with initial concentration of H2S varied between 5 and 25 vol% at 150 mL/min （at standard temperature and pressure） flow rate in the input power range of 0.5 to 2 W. The reaction rate model based on continuous stirred tank reactor （CSTR） model failed to explain the global kinetics of H2S decomposition, probably due to the multiple complex reactions involved in H2S decomposition, whereas Michaelis-Menten model was satisfactory. Typical results indicated that the reaction order approached zero with increasing inlet concentration.

Hydrogen sulfide intervention in focal cerebral ischemia/reperfusion injury in rats

The present study aimed to explore the mechanism underlying the protective effects of hydrogen sulfide against neuronal damage caused by cerebral ischemia/reperfusion. We established the middle cerebral artery occlusion model in rats via the suture method. Ten minutes after middle cerebral artery occlusion, the animals were intraperitoneally injected with hydrogen sulfide donor compound sodium hydrosulfide. Immunofluorescence revealed that the immunoreactivity of P2X7 in the cerebral cortex and hippocampal CA1 region in rats with cerebral ischemia/reperfusion injury decreased with hydrogen sulfide treatment. Furthermore, treatment of these rats with hydrogen sulfide significantly lowered mortality, the Longa neurological deficit scores, and infarct volume. These results indicate that hydrogen sulfide may be protective in rats with local cerebral ischemia/reperfusion injury by down-regulating the expression of P2X7 receptors.

Hydrogen sulfide attenuates gastric mucosal injury induced by restraint water-immersion stress via activation of KATPchannel and NF-κB dependent pathway

AIMTo explore the effect of hydrogen sulfide (H2S) on restraint water-immersion stress (RWIS)-induced gastric lesions in rats and the influence of adenosine triphosphate (ATP)-sensitive potassium (KATP) channels and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway on such an effect.METHODSMale Wistar rats were randomly divided into a control group, a physiological saline (PS) group, a sodium hydrosulfide (NaHS) group, a glibenclamide (Gl) group, Gl plus NaHS group, a pyrrolidine dithiocarbamate (PDTC) group, and a PDTC plus NaHS group. Gastric mucosal injury was induced by RWIS for 3 h in rats, and gastric mucosal damage was analyzed after that. The PS, NaHS (100 μmol/kg body weight), Gl (100 μmol/kg body weight), Gl (100 μmol/kg or 150 μmol/kg body weight) plus NaHS (100 μmol/kg body weight), PDTC (100 μmol/kg body weight), and PDTC (100 μmol/kg body weight) plus NaHS (100 μmol/kg body weight) were respectively injected intravenously before RWIS.RESULTSRWIS induced serious gastric lesions in the rats in the PS pretreatment group. The pretreatment of NaHS (a H2S donor) significantly reduced the damage induced by RWIS. The gastric protective effect of the NaHS during RWIS was attenuated by PDTC, an NF-κB inhibitor, and also by glibenclamide, an ATP-sensitive potassium channel blocker, in a dose-dependent manner.CONCLUSIONThese results suggest that exogenous H2S plays a protective role against RWIS injury in rats, possibly through modulation of KATP channel opening and the NF-κB dependent pathway.

Advances in depressants for flotation separation of Cu–Fe sulfide minerals at low alkalinity:A critical review

The flotation separation of Cu–Fe sulfide minerals at low alkalinity can be achieved using selective depressants.In the flotation system of Cu–Fe sulfide minerals,depressants usually preferentially interact with the pyrite surface to render the mineral surface hydrophilic and hinder the adsorption of the collector.This review summarizes the advances in depressants for the flotation separation of Cu–Fe sulfide minerals at low alkalinity.These advances include use of inorganic depressants (oxidants and sulfur–oxygen compounds),natural polysaccharides (starch,dextrin,konjac glucomannan,and galactomannan),modified polymers (carboxymethyl cellulose,polyacrylamide,lignosulfonate,and tricarboxylate sodium starch),organic acids (polyglutamic acid,sodium humate,tannic acid,pyrogallic acid,salicylic acid,and lactic acid),sodium dimethyl dithiocarbamate,and diethylenetriamine.The potential application of specific inorganic and organic depressants in the flotation separation of Cu–Fe sulfide minerals at low alkalinity is reviewed.The advances in the use of organic depressants with respect to the flotation separation of Cu–Fe sulfide minerals are comprehensively detailed.Additionally,the depression performances and mechanisms of different types of organic depressants on mineral surfaces are summarized.Finally,several perspectives on depressants vis-à-vis flotation separation of Cu–Fe sulfide minerals at low alkalinity are proposed.

Biological removal of air loaded with a hydrogen sulfide and ammonia mixture

The nuisance impact of air pollutant emissions from wastewater pumping stations is a major issue of concern to China. Hydrogen sulfide and ammonia are commonly the primary odor and are important targets for removal. An alternative control technology, biofiltration, was studied. The aim of this study is to investigate the potential of unit systems packed with compost in terms of ammonia and hydrogen sulfide emissions treatment, and to establish optimal operating conditions for a full-scale conceptual design. The laboratory scale biofilter packed with compost was continuously supplied with hydrogen sulfide and ammonia gas mixtures. A volumetric load of less than 150 gH 2S/(m3·d) and 230 gNH 3/(m3·d) was applied for about fifteen weeks. Hydrogen sulfide and ammonia elimination occurred in the biofilter simultaneously. The removal efficiency, removal capacity and removal kinetics in the biofilter were studied. The hydrogen sulfide removal efficiency reached was very high above 99%, and ammonia removal efficiency was about 80%. Hydrogen sulfide was oxidized into sulphate. The ammonia oxidation products were nitrite and nitrate. Ammonia in the biofilter was mainly removed by adsorption onto the carrier material and by absorption into the water fraction of the carrier material. High percentages of hydrogen sulfide or ammonia were oxidized in the first section of the column. Through kinetics analysis, the presence of ammonia did not hinder the hydrogen sulfide removal. According to the relationship between pressure drop and gas velocity for the biofilter and Reynolds number, non-Darcy flow can be assumed to represent the flow in the medium.

Study on hydrogen sulfide removal based on bench-scale experiment by bio-trickling filter

A bench-scale experiment for control of hydrogen sulfide （H2S） emissions was carried out continuously for nearly four months by using bio-trickling filter packed with ZX01 stuffing. The results suggested that the bio-trickling filter had proven excellent performance over substantial operational periods. Removal efficiency of H2S was nearly 100% when volumetric loading of the bio-trickling filter varied from 0.64 g/（m^3·h） to 38.20 g/（m^3·h） and metabolism products of H2S were mainly composed of SO4^2-. When inlet concentration of H2S was 250 mg/m^3, the optimum gas retention time was 30 s and the optimum spray water flow rate was 0.005 9-0.012 L/（cm^2·h）. The bio-trickling filter had good ability to resist shock of high volumetric loading, and was not blocked during experiments for nearly four months during which resistance was maintained at relatively lower value, so that the bio-trickling filter need not carry out back washing frequently and can be operated steadily for long-term.