Melatonin (MEL) was investigated for protection against the anthracycline antibiotic doxorubicin (Dox) that is well known for its oxidative damage to various body organs. It was aimed to have a comparison of this prot...Melatonin (MEL) was investigated for protection against the anthracycline antibiotic doxorubicin (Dox) that is well known for its oxidative damage to various body organs. It was aimed to have a comparison of this protection to heart, liver and kidney in the treated subjects. In this study, groups of mice were treated with Dox and melatonin and their individual or combined effects were evaluated by assessing lipidperoxidation, non-protein sulfhydryls (NP-SH) and nitrate/nitrite (NO) contents in these tissues. Plasma aminotransferases, LDH and CK-MB enzyme activities were measured. Moreover, these tissues were subject to histopathological assessment. MEL co-treatment significantly prevented any rise in lipidperoxides more significantly in heart and liver as compared to kidney. In tandem, MEL prevented a decline in GSH that was observed by Dox alone in liver and kidney. Dox significantly increased total NO levels in all the tissues. Melatonin at both dose levels could not afford protection against nitrosative stress. MEL in combination treatment provided significant展开更多
The authors dealt with the effects of dynamic high pressure micro-fluidization(untreated and 20-160 MPa treated) on the structure and physico-chemical properties of egg white solutions[6%(mass fraction) or 61.2 mg...The authors dealt with the effects of dynamic high pressure micro-fluidization(untreated and 20-160 MPa treated) on the structure and physico-chemical properties of egg white solutions[6%(mass fraction) or 61.2 mg protein/mL]. Micro-fluidization treatment resulted in a decrease in mean particle size, and little change in solubility. It was found that the residual denaturation enthalpy was decreased with the increase of pressure from 20 to 100 MPa and from 120 to 160 MPa, reaching into the maximum at 160 MPa. There was an increase of surface hydrophobicity with the maximum at 100 MPa observed. Simultaneously, micro-fluidization treatment also resulted in a decrease in the content of sulfhydryl groups.展开更多
BACKGROUND: Carbon monoxide poisoning(COP) is an important cause of mortality and morbidity worldwide. This study was to investigate the levels of serum paraoxonase(PON), arylesterase(ARYL), ceruloplasmin(Cp), and sul...BACKGROUND: Carbon monoxide poisoning(COP) is an important cause of mortality and morbidity worldwide. This study was to investigate the levels of serum paraoxonase(PON), arylesterase(ARYL), ceruloplasmin(Cp), and sulfhydryl(-SH) in the treatment of COP, and to further understand the pathophysiology of COP.METHODS: This prospective study comprised 107 individuals with COP(group 1) and 50 healthy volunteers(group 2). Serum, plasma, and erythrocyte samples were taken on admission from all participants with COP. This process was repeated in the 90 th and 180 th minutes of treatment. Samples were taken from the control group only once. The levels of plasma PON, ARYL, Cp activity and-SH were measured in both groups.RESULTS: Age, gender, and carboxyhemoglobin level were not correlated with PON, ARYL, Cp, and-SH levels. PON, ARYL, and-SH levels were signifi cantly decreased in group 1 compared with group 2. Conversely, Cp was signifi cantly elevated in group 1 in contrast to group 2. Although ARYL was lower on admission in patients with COP than that was observed in the 90 th and 180 th minutes(P<0.001), Cp was higher on admission than at the other time points(P<0.001).CONCLUSIONS: Participants with COP had decreased levels of antioxidants(PON, ARLY, and-SH). COP represses the antioxidant system.展开更多
Significant correlations exist for the total sample between the dough viscoelastic properties and quality, but little information about these links is available. This study investigates the relationship between the gl...Significant correlations exist for the total sample between the dough viscoelastic properties and quality, but little information about these links is available. This study investigates the relationship between the gluten molecular conformation and the dough viscoelastic properties of the Zhengmai 379 wheat variety with different relative humidity(RH) values during storage.The results showed that protein extractability, free sulfhydryl(SH) groups, and wet gluten contents decreased to a certain degree during storage, while the glutenin quantity significantly varied. Significant negative correlation coefficients were found between the dough viscosity at 50% RH and the β-turn contents at 40% RH(-0.918) or 60% RH(-0.949)(P < 0.01), the dough viscosity at50% RH and the β-turn contents at 50% RH(-0.912)(P < 0.05), and the dough viscosity at 50% RH and the α-helix/β-sheet ratio at 40% RH(-0.875), 50% RH(-0.869), or 60% RH(-0.843)(P < 0.05). Significant correlation coefficients were further observed between the dough viscosity at 50% RH and the β-sheet contents at 60% RH(0.927)(P < 0.01) and between the dough viscosity at50% RH and the β-sheet contents at 40% RH(0.910) or 50% RH(0.908)(P < 0.05). A decrease in the free SH groups of gluten and an increase in the low-molecular weight contents suggested that gliadin was incorporated via SS crosslinking to the glutenin-like protein, which did not dissolve in ethanol.展开更多
The studies were performed to investigate the mechanism of phenamiphos affecting muscarinic acetylcholine receptor (M-AchR) of the brain synaptosome in rats.The results showed that phenamiphos inhibited the binding of...The studies were performed to investigate the mechanism of phenamiphos affecting muscarinic acetylcholine receptor (M-AchR) of the brain synaptosome in rats.The results showed that phenamiphos inhibited the binding of 3H-quinuclidinyl benzilate (3H-QNB) to the brain synaptosome in rats, and this effect was dose and time-depen dent. This suggests that phenamiphos might directly affect M-AchR. The KD and Bmax of phenamiphos to M-AchR were measured and found to be 1. 3 × 10-7 mol/L and 4. 57pmol/mg protein, respectively. It belongs to non-specific inhibition of phenamiphos on the binding of 3H-QNB to M-AchR. It was also found that phenamiphos decreased the level of protein sulfhydryl group in brain synaptosome membrane. Dithiothreitol (DTT) and the reduced glutathion (GSH) prevented the decrease of protein sulfhydrylgroup and the inhibition of phenamiphos on the binding of 3H-QNB to M-AchR. These showed that phenamiphos could affect the sulfhydryl group of M-AchR surface.展开更多
According to our research, the use of radon inhalation in experimental animals, particularly in genetically determined rats with epileptic seizures, altered all parameters of the epileptic seizure development picture,...According to our research, the use of radon inhalation in experimental animals, particularly in genetically determined rats with epileptic seizures, altered all parameters of the epileptic seizure development picture, namely the hidden period, the first and second wild jog duration after the audiogenic signal. On the third day, no response to the audiogenic signal was observed at all, and not even a single episode of tonic-clonic seizures. All mentioned suggest that radon inhalation could be used to treat epilepsy. Presented study is the first precedent of attempt R-Ho through inhalation for treatment of epileptic seizures in animal models with further translation to clinical study in humans through pilot phase II study. More profound and scientifically systematized approach is needed to determine uniqueness of Tskhaltubo water springs, great importance investigation of the mechanisms of radon effects on the excitatory and inhibitory functioning of CNS and further clinical studies to establish its effect on humans.展开更多
Induced-acetaldehyde toxic effects on gluatathione [GSH] metabolism and sulfhydryl (SH) groups in liver and in brain of female albino rats with reference to age was studied.The total -SH groups were decreased whereas ...Induced-acetaldehyde toxic effects on gluatathione [GSH] metabolism and sulfhydryl (SH) groups in liver and in brain of female albino rats with reference to age was studied.The total -SH groups were decreased whereas the specific activities of glutathione-S-transferase [GST] and glutathione peroxidase [GP0] were increased in acetaldehyde treated rats. However, the specific activity levels of glutathione reductase [GR] and Γ-glutamylcysteine synthetase [Γ-GCS] were decreased. In general, acetaldehyde indueed changes in the specific activities of the enzymes that increase with increasing age展开更多
Sickle cell disease(SCD) is the first molecular disease in the literature. Although the structural alteration and dysfunction of the sickle hemoglobin(HbS) are well understood, the many factors modifying the clinical ...Sickle cell disease(SCD) is the first molecular disease in the literature. Although the structural alteration and dysfunction of the sickle hemoglobin(HbS) are well understood, the many factors modifying the clinical signs and symptoms of the disease are under investigation. Besides having an abnormal electrophoretic mobility and solubility, HbS is unstable. The autooxidation rate of the abnormal HbS has been reported to be almost two times of the normal. There are two more components of the oxidative damage in SCD: Free radical induced oxidative damage during vaso-occlusion induced ischemia-reperfusion injury and decreased antioxidant capacity in the erythrocyte and in the circulation. We will discuss the effects of oxidative alterations in the erythrocyte and in the plasma of SCD patients in this review.展开更多
Gold(Au)nanoclusters supported on various supports have been widely used in the fields of energy and catalysis.However,the poor thermal stability of Au nanoclusters on the support interface usually leads to a reductio...Gold(Au)nanoclusters supported on various supports have been widely used in the fields of energy and catalysis.However,the poor thermal stability of Au nanoclusters on the support interface usually leads to a reduction or even loss of catalytic activity.Herein,we used an in situ reduction method to synthesize Au nanoclusters on ceria(CeO_(2))carriers.In this method,sulfhydryl groups were used to modify CeO_(2) nanospheres first,and then Au clusters with an average diameter of 1.5 nm were grown on the surface of ceria reduced with sodium borohydride.The presence of the Au-S-Ce structure enhances the electron transfer efficiency,making the material exhibit high CO oxidation activity at room temperature.Furthermore,due to the strong binding energy of S and Au,the material exhibits a high stability for long time running process.This strategy provides an idea for designing stable and active supported ultrasmall Au nanoclusters catalytic materials.展开更多
Objective To observe sulfhydryl compound variation in the injury of pancreatic cells and the effects of external sulfhydryl compounds on cytoprotection.Methods Male Wistar mice were divided randomly into three group...Objective To observe sulfhydryl compound variation in the injury of pancreatic cells and the effects of external sulfhydryl compounds on cytoprotection.Methods Male Wistar mice were divided randomly into three groups: groups A and B served as animal models (retrograde duct infusion with 5% sodium taurocholate), in group A, 45 animals were treated with normal saline therapy, in group B, 45 aminals were treated with Tiopronin therapy; and group C, 15 animals, were designated as normal control. Animals were killed at 2, 4, 6, 12 and 24 h, and pancreatic tissue was analyzed for total sulfhydryl (TSH), nonprotein sulfhydryl (NPSH) and malondialdehyde (MDA). Histopathology, serum amylase (Sam) and C reactive protein (CRP) were assessed as well.Results Levels of Sam and CRP increased in both group A and group B, with corresponding pathological changes of acute nerotic pancreatitis (ANP). Levels of TSH, NPSH and protein sulfhydryl (PSH) in group A decreased markedly during pancreatitis (P<0.01), but MDA increased significantly (P<0.01). The depletion of NPSH in group B was markedly ameliorated at 4 h or 6 h, when Tiopronin was prophylactically administered (P<0.05), after which the level of MDA showed very little increase when compared to group A (P<0.01). Histopathological damage was attenuated to a certain extent, in regards to serum amylase and CRP.Conclusions All sulfhydryl compounds decreased significantly during ANP; external sulfhydryl compound could protect the pancreatic cells most likely as a type of scavengers of oxygen free radicals, which are critically involved in the pathophysiology of ANP. Sulfhydryl plays an important role in the action of pancreatic cytoprotection.展开更多
Biochar is an effective absorbent for remediating heavy metal contaminated soil,but functional optimization is still needed to improve its performance in field application.Here,we characterized the physical structures...Biochar is an effective absorbent for remediating heavy metal contaminated soil,but functional optimization is still needed to improve its performance in field application.Here,we characterized the physical structures and surface chemical properties of raw wood biochar and palm biochar(WB and PB)and the corresponding sulfhydryl-modified biochar(SWB and SPB).Their adsorption capacity for Pb was evaluated by combining thermodynamic and kinetic adsorption at 0.01 mol/L KCl and corresponding model simulation.The results demonstrated successful grafting of sulfhydryl groups onto the biochar,which dramatically reduced the specific surface area(SSA)and pore volume of biochar.The pKa in the surface complexation model(SCM)indicated similar proton affinity between sulfhydryl groups and original functional groups on the biochar.SCM could satisfactorily fit the Pb adsorption behaviors,and model analysis revealed that Pb tended to be adsorbed on low-proton affin-ity sites at low pH,but high-proton affinity sites became dominant in Pb adsorption with increasing pH and adsorbed almost all Pb ions at pH>7.0.Besides,the Pb adsorption density of SWB and SPB was improved by 8.86 and 3.64 folds relative to that of WB and PB,respectively.Over 90% of initially added Pb ions were removed in 1440 and 720 min by raw and sulfhydryl-modified biochar,respectively,indicating that sulfhydryl modification accelerated the Pb adsorption of biochar.These results suggest that site density,SSA and pore structure of biochar play crucial roles in heavy metal adsorption,and sulfhydryl modification may improve the performance of biochar in remediating heavy metal contaminated soil.展开更多
Conventional strategies for highly reversible Zn anodes usually involve complex and time-consuming production processes of current collectors,expensive and toxic electrolyte additives,or the introduction of inactive m...Conventional strategies for highly reversible Zn anodes usually involve complex and time-consuming production processes of current collectors,expensive and toxic electrolyte additives,or the introduction of inactive materials in protective layer.Here,we develop a fast,facile,and environmentally friendly biopolishing method to prepare dendrite-free Zn anodes,which merely involves the simple immersion of Zn foil in a biocompatible cysteine aqueous solution.The ravine structure formed by sulfhydryl etching for 30 min not only increases the electroactive area of Zn anode but also regulates the distribution of electric field and Zn ions,ensuring the homogeneous deposition and stripping of Zn ions.The biopolished Zn anode can be operated steadily for 2,000 h with a low voltage hysteresis at a current density of 1 mA·cm^(−2).In addition,Zn anodes with a cycle life of 500 h can be built by soaking for only 5 min,proving the high efficiency of the proposed method.This strategy is generalized to substances with sulfhydryl groups for polishing Zn electrodes with improved performance.The cysteine-polished Zn//activated carbon supercapacitor can stably run for 20,000 cycles without obvious capacity attenuation.The proposed strategy shows potential for producing advanced Zn anodes.展开更多
We demonstrate improved peptide linkers which allow both conjugation to biomolecules such as DNA and self-assembly with luminescent semiconductor quantum dots.A hexahistidine peptidyl sequence was generated by standar...We demonstrate improved peptide linkers which allow both conjugation to biomolecules such as DNA and self-assembly with luminescent semiconductor quantum dots.A hexahistidine peptidyl sequence was generated by standard solid phase peptide synthesis and modified with the succinimidyl ester of iodoacetamide to yield a thiol-reactive iodoacetyl polyhistidine linker.The reactive peptide was conjugated to dye-labeled thiolated DNA which was utilized as a model target biomolecule.Agarose gel electrophoresis and fluorescence resonance energy transfer analysis confirmed that the linker allowed the DNA to self-assemble with quantum dots via metal-affinity driven coordination.In contrast to previous peptidyl linkers that were based on disulfide exchange and were thus labile to reduction,the reactive haloacetyl chemistry demonstrated here results in a more stable thioether bond linking the DNA to the peptide which can withstand strongly reducing environments such as the intracellular cytoplasm.As thiol groups occur naturally in proteins,can be engineered into cloned proteins,inserted into nascent peptides or added to DNA during synthesis,the chemistry demonstrated here can provide a simple method for self-assembling a variety of stable quantum dot bioconjugates.展开更多
Abstract Objective To conduct a screening survey of glycophorin (GP) variants and observe the content changes of sialic acid (SA) and total sulfhydryl (SH) groups on the erythrocyte membranes among residents in a...Abstract Objective To conduct a screening survey of glycophorin (GP) variants and observe the content changes of sialic acid (SA) and total sulfhydryl (SH) groups on the erythrocyte membranes among residents in a tertian malaria hyperendemic area of Guizhou Province. Methods GP variants were detected in the erythrocyte hemolysates of 173 local residents at two villages of Libo County by SDS PAGE on 10% to 15% gradients gel and Western immunoblotting. Their SA and total SH group contents were estimated in erythrocyte membranes by spectrophotometric methods. 114 healthy subjects in Changsha and 49 individuals at a neighbouring village of the above area showing low morbidity of malaria served as normal and endemic controls respectively. Results Three distinct types of GP variants were found among 19 propositi in this hyperendemic area. The incidence of GP variants was 7.9% (8/101) at Yaolu Village whose population was mainly composed of Yao ethnic group;while that of Buyi ethnic group at Maolan Village was higher (15.3%; 11/72).The erythrocyte membrane contents of SA in residents at both villages exhibited a very significant tendency of decline (P<0.01), whereas those of total SH groups increased prominently in residents of Yaolu Village only (P<0.05). Conclusions The frequency of GP variants in this hyperendemic area does not depend upon the severity of malarial prevalence. The evident reduction of SA contents in the residents may be related to the breaking down of the SA residues on membrane GPs by the invasion of Plasmodium vivax.展开更多
文摘Melatonin (MEL) was investigated for protection against the anthracycline antibiotic doxorubicin (Dox) that is well known for its oxidative damage to various body organs. It was aimed to have a comparison of this protection to heart, liver and kidney in the treated subjects. In this study, groups of mice were treated with Dox and melatonin and their individual or combined effects were evaluated by assessing lipidperoxidation, non-protein sulfhydryls (NP-SH) and nitrate/nitrite (NO) contents in these tissues. Plasma aminotransferases, LDH and CK-MB enzyme activities were measured. Moreover, these tissues were subject to histopathological assessment. MEL co-treatment significantly prevented any rise in lipidperoxides more significantly in heart and liver as compared to kidney. In tandem, MEL prevented a decline in GSH that was observed by Dox alone in liver and kidney. Dox significantly increased total NO levels in all the tissues. Melatonin at both dose levels could not afford protection against nitrosative stress. MEL in combination treatment provided significant
基金Supported by the National Natural Science Foundation of China(No.20666004)Program for Changjiang Scholars and Innovative Research Team in University of China(No.IRT0540)
文摘The authors dealt with the effects of dynamic high pressure micro-fluidization(untreated and 20-160 MPa treated) on the structure and physico-chemical properties of egg white solutions[6%(mass fraction) or 61.2 mg protein/mL]. Micro-fluidization treatment resulted in a decrease in mean particle size, and little change in solubility. It was found that the residual denaturation enthalpy was decreased with the increase of pressure from 20 to 100 MPa and from 120 to 160 MPa, reaching into the maximum at 160 MPa. There was an increase of surface hydrophobicity with the maximum at 100 MPa observed. Simultaneously, micro-fluidization treatment also resulted in a decrease in the content of sulfhydryl groups.
文摘BACKGROUND: Carbon monoxide poisoning(COP) is an important cause of mortality and morbidity worldwide. This study was to investigate the levels of serum paraoxonase(PON), arylesterase(ARYL), ceruloplasmin(Cp), and sulfhydryl(-SH) in the treatment of COP, and to further understand the pathophysiology of COP.METHODS: This prospective study comprised 107 individuals with COP(group 1) and 50 healthy volunteers(group 2). Serum, plasma, and erythrocyte samples were taken on admission from all participants with COP. This process was repeated in the 90 th and 180 th minutes of treatment. Samples were taken from the control group only once. The levels of plasma PON, ARYL, Cp activity and-SH were measured in both groups.RESULTS: Age, gender, and carboxyhemoglobin level were not correlated with PON, ARYL, Cp, and-SH levels. PON, ARYL, and-SH levels were signifi cantly decreased in group 1 compared with group 2. Conversely, Cp was signifi cantly elevated in group 1 in contrast to group 2. Although ARYL was lower on admission in patients with COP than that was observed in the 90 th and 180 th minutes(P<0.001), Cp was higher on admission than at the other time points(P<0.001).CONCLUSIONS: Participants with COP had decreased levels of antioxidants(PON, ARLY, and-SH). COP represses the antioxidant system.
基金Supported by National Key Research and Development Program(2016YFD0400203)National Natural Science Foundation of China(31571780 and 31771897)+2 种基金General Science and Technology Research Projects of Zhengzhou(N2013G0077)Key Scientific Research Project of Universities in Henan Province(16A210018)the focus on Fostering Basic Research Fund of Henan University of Technology(2013JCYJ05)
文摘Significant correlations exist for the total sample between the dough viscoelastic properties and quality, but little information about these links is available. This study investigates the relationship between the gluten molecular conformation and the dough viscoelastic properties of the Zhengmai 379 wheat variety with different relative humidity(RH) values during storage.The results showed that protein extractability, free sulfhydryl(SH) groups, and wet gluten contents decreased to a certain degree during storage, while the glutenin quantity significantly varied. Significant negative correlation coefficients were found between the dough viscosity at 50% RH and the β-turn contents at 40% RH(-0.918) or 60% RH(-0.949)(P < 0.01), the dough viscosity at50% RH and the β-turn contents at 50% RH(-0.912)(P < 0.05), and the dough viscosity at 50% RH and the α-helix/β-sheet ratio at 40% RH(-0.875), 50% RH(-0.869), or 60% RH(-0.843)(P < 0.05). Significant correlation coefficients were further observed between the dough viscosity at 50% RH and the β-sheet contents at 60% RH(0.927)(P < 0.01) and between the dough viscosity at50% RH and the β-sheet contents at 40% RH(0.910) or 50% RH(0.908)(P < 0.05). A decrease in the free SH groups of gluten and an increase in the low-molecular weight contents suggested that gliadin was incorporated via SS crosslinking to the glutenin-like protein, which did not dissolve in ethanol.
文摘The studies were performed to investigate the mechanism of phenamiphos affecting muscarinic acetylcholine receptor (M-AchR) of the brain synaptosome in rats.The results showed that phenamiphos inhibited the binding of 3H-quinuclidinyl benzilate (3H-QNB) to the brain synaptosome in rats, and this effect was dose and time-depen dent. This suggests that phenamiphos might directly affect M-AchR. The KD and Bmax of phenamiphos to M-AchR were measured and found to be 1. 3 × 10-7 mol/L and 4. 57pmol/mg protein, respectively. It belongs to non-specific inhibition of phenamiphos on the binding of 3H-QNB to M-AchR. It was also found that phenamiphos decreased the level of protein sulfhydryl group in brain synaptosome membrane. Dithiothreitol (DTT) and the reduced glutathion (GSH) prevented the decrease of protein sulfhydrylgroup and the inhibition of phenamiphos on the binding of 3H-QNB to M-AchR. These showed that phenamiphos could affect the sulfhydryl group of M-AchR surface.
文摘According to our research, the use of radon inhalation in experimental animals, particularly in genetically determined rats with epileptic seizures, altered all parameters of the epileptic seizure development picture, namely the hidden period, the first and second wild jog duration after the audiogenic signal. On the third day, no response to the audiogenic signal was observed at all, and not even a single episode of tonic-clonic seizures. All mentioned suggest that radon inhalation could be used to treat epilepsy. Presented study is the first precedent of attempt R-Ho through inhalation for treatment of epileptic seizures in animal models with further translation to clinical study in humans through pilot phase II study. More profound and scientifically systematized approach is needed to determine uniqueness of Tskhaltubo water springs, great importance investigation of the mechanisms of radon effects on the excitatory and inhibitory functioning of CNS and further clinical studies to establish its effect on humans.
文摘Induced-acetaldehyde toxic effects on gluatathione [GSH] metabolism and sulfhydryl (SH) groups in liver and in brain of female albino rats with reference to age was studied.The total -SH groups were decreased whereas the specific activities of glutathione-S-transferase [GST] and glutathione peroxidase [GP0] were increased in acetaldehyde treated rats. However, the specific activity levels of glutathione reductase [GR] and Γ-glutamylcysteine synthetase [Γ-GCS] were decreased. In general, acetaldehyde indueed changes in the specific activities of the enzymes that increase with increasing age
文摘Sickle cell disease(SCD) is the first molecular disease in the literature. Although the structural alteration and dysfunction of the sickle hemoglobin(HbS) are well understood, the many factors modifying the clinical signs and symptoms of the disease are under investigation. Besides having an abnormal electrophoretic mobility and solubility, HbS is unstable. The autooxidation rate of the abnormal HbS has been reported to be almost two times of the normal. There are two more components of the oxidative damage in SCD: Free radical induced oxidative damage during vaso-occlusion induced ischemia-reperfusion injury and decreased antioxidant capacity in the erythrocyte and in the circulation. We will discuss the effects of oxidative alterations in the erythrocyte and in the plasma of SCD patients in this review.
基金supported by the National Science and Technology Major Project of China(No.2021YFB3500700)the National Natural Science Foundation of China(Nos.22020102003,22025506)+1 种基金the Key Research Program of the Chinese Academy of Sciences(No.ZDRW-CN-2021-3-3)the K.C.Wong Education Foundation,China(No.GJTD-2018-09).
文摘Gold(Au)nanoclusters supported on various supports have been widely used in the fields of energy and catalysis.However,the poor thermal stability of Au nanoclusters on the support interface usually leads to a reduction or even loss of catalytic activity.Herein,we used an in situ reduction method to synthesize Au nanoclusters on ceria(CeO_(2))carriers.In this method,sulfhydryl groups were used to modify CeO_(2) nanospheres first,and then Au clusters with an average diameter of 1.5 nm were grown on the surface of ceria reduced with sodium borohydride.The presence of the Au-S-Ce structure enhances the electron transfer efficiency,making the material exhibit high CO oxidation activity at room temperature.Furthermore,due to the strong binding energy of S and Au,the material exhibits a high stability for long time running process.This strategy provides an idea for designing stable and active supported ultrasmall Au nanoclusters catalytic materials.
文摘Objective To observe sulfhydryl compound variation in the injury of pancreatic cells and the effects of external sulfhydryl compounds on cytoprotection.Methods Male Wistar mice were divided randomly into three groups: groups A and B served as animal models (retrograde duct infusion with 5% sodium taurocholate), in group A, 45 animals were treated with normal saline therapy, in group B, 45 aminals were treated with Tiopronin therapy; and group C, 15 animals, were designated as normal control. Animals were killed at 2, 4, 6, 12 and 24 h, and pancreatic tissue was analyzed for total sulfhydryl (TSH), nonprotein sulfhydryl (NPSH) and malondialdehyde (MDA). Histopathology, serum amylase (Sam) and C reactive protein (CRP) were assessed as well.Results Levels of Sam and CRP increased in both group A and group B, with corresponding pathological changes of acute nerotic pancreatitis (ANP). Levels of TSH, NPSH and protein sulfhydryl (PSH) in group A decreased markedly during pancreatitis (P<0.01), but MDA increased significantly (P<0.01). The depletion of NPSH in group B was markedly ameliorated at 4 h or 6 h, when Tiopronin was prophylactically administered (P<0.05), after which the level of MDA showed very little increase when compared to group A (P<0.01). Histopathological damage was attenuated to a certain extent, in regards to serum amylase and CRP.Conclusions All sulfhydryl compounds decreased significantly during ANP; external sulfhydryl compound could protect the pancreatic cells most likely as a type of scavengers of oxygen free radicals, which are critically involved in the pathophysiology of ANP. Sulfhydryl plays an important role in the action of pancreatic cytoprotection.
基金This research was supported by the National Natural Science Foundation of China(Nos.41601231 and 41425006)We are also thankful to Prof.Zuoxiong Liu from the Foreign Language School of HZAU for his help to edit and polish the English language of the manuscript.
文摘Biochar is an effective absorbent for remediating heavy metal contaminated soil,but functional optimization is still needed to improve its performance in field application.Here,we characterized the physical structures and surface chemical properties of raw wood biochar and palm biochar(WB and PB)and the corresponding sulfhydryl-modified biochar(SWB and SPB).Their adsorption capacity for Pb was evaluated by combining thermodynamic and kinetic adsorption at 0.01 mol/L KCl and corresponding model simulation.The results demonstrated successful grafting of sulfhydryl groups onto the biochar,which dramatically reduced the specific surface area(SSA)and pore volume of biochar.The pKa in the surface complexation model(SCM)indicated similar proton affinity between sulfhydryl groups and original functional groups on the biochar.SCM could satisfactorily fit the Pb adsorption behaviors,and model analysis revealed that Pb tended to be adsorbed on low-proton affin-ity sites at low pH,but high-proton affinity sites became dominant in Pb adsorption with increasing pH and adsorbed almost all Pb ions at pH>7.0.Besides,the Pb adsorption density of SWB and SPB was improved by 8.86 and 3.64 folds relative to that of WB and PB,respectively.Over 90% of initially added Pb ions were removed in 1440 and 720 min by raw and sulfhydryl-modified biochar,respectively,indicating that sulfhydryl modification accelerated the Pb adsorption of biochar.These results suggest that site density,SSA and pore structure of biochar play crucial roles in heavy metal adsorption,and sulfhydryl modification may improve the performance of biochar in remediating heavy metal contaminated soil.
基金supported by the National Natural Science Foundation of China(Nos.21825106 and 92061201)the Program for Innovative Research Team(in Science and Technology)in Universities of Henan Province(No.19IRTSTHN022)Zhengzhou University。
文摘Conventional strategies for highly reversible Zn anodes usually involve complex and time-consuming production processes of current collectors,expensive and toxic electrolyte additives,or the introduction of inactive materials in protective layer.Here,we develop a fast,facile,and environmentally friendly biopolishing method to prepare dendrite-free Zn anodes,which merely involves the simple immersion of Zn foil in a biocompatible cysteine aqueous solution.The ravine structure formed by sulfhydryl etching for 30 min not only increases the electroactive area of Zn anode but also regulates the distribution of electric field and Zn ions,ensuring the homogeneous deposition and stripping of Zn ions.The biopolished Zn anode can be operated steadily for 2,000 h with a low voltage hysteresis at a current density of 1 mA·cm^(−2).In addition,Zn anodes with a cycle life of 500 h can be built by soaking for only 5 min,proving the high efficiency of the proposed method.This strategy is generalized to substances with sulfhydryl groups for polishing Zn electrodes with improved performance.The cysteine-polished Zn//activated carbon supercapacitor can stably run for 20,000 cycles without obvious capacity attenuation.The proposed strategy shows potential for producing advanced Zn anodes.
基金The authors acknowledge Stephen Lee and Ilya Elashvilli of the CB Directorate/Physical S&T Division(DTRA),ONR,NRL,and the NRLNSI for financial support.
文摘We demonstrate improved peptide linkers which allow both conjugation to biomolecules such as DNA and self-assembly with luminescent semiconductor quantum dots.A hexahistidine peptidyl sequence was generated by standard solid phase peptide synthesis and modified with the succinimidyl ester of iodoacetamide to yield a thiol-reactive iodoacetyl polyhistidine linker.The reactive peptide was conjugated to dye-labeled thiolated DNA which was utilized as a model target biomolecule.Agarose gel electrophoresis and fluorescence resonance energy transfer analysis confirmed that the linker allowed the DNA to self-assemble with quantum dots via metal-affinity driven coordination.In contrast to previous peptidyl linkers that were based on disulfide exchange and were thus labile to reduction,the reactive haloacetyl chemistry demonstrated here results in a more stable thioether bond linking the DNA to the peptide which can withstand strongly reducing environments such as the intracellular cytoplasm.As thiol groups occur naturally in proteins,can be engineered into cloned proteins,inserted into nascent peptides or added to DNA during synthesis,the chemistry demonstrated here can provide a simple method for self-assembling a variety of stable quantum dot bioconjugates.
文摘Abstract Objective To conduct a screening survey of glycophorin (GP) variants and observe the content changes of sialic acid (SA) and total sulfhydryl (SH) groups on the erythrocyte membranes among residents in a tertian malaria hyperendemic area of Guizhou Province. Methods GP variants were detected in the erythrocyte hemolysates of 173 local residents at two villages of Libo County by SDS PAGE on 10% to 15% gradients gel and Western immunoblotting. Their SA and total SH group contents were estimated in erythrocyte membranes by spectrophotometric methods. 114 healthy subjects in Changsha and 49 individuals at a neighbouring village of the above area showing low morbidity of malaria served as normal and endemic controls respectively. Results Three distinct types of GP variants were found among 19 propositi in this hyperendemic area. The incidence of GP variants was 7.9% (8/101) at Yaolu Village whose population was mainly composed of Yao ethnic group;while that of Buyi ethnic group at Maolan Village was higher (15.3%; 11/72).The erythrocyte membrane contents of SA in residents at both villages exhibited a very significant tendency of decline (P<0.01), whereas those of total SH groups increased prominently in residents of Yaolu Village only (P<0.05). Conclusions The frequency of GP variants in this hyperendemic area does not depend upon the severity of malarial prevalence. The evident reduction of SA contents in the residents may be related to the breaking down of the SA residues on membrane GPs by the invasion of Plasmodium vivax.