Supplemental effect of varying L-cysteine concentrations on the quality of cryopreserved boar semen

Cryopreservation is associated with the production of reactive oxygen species, which leads to lipid peroxidation of the sperm membrane and consequently a reduction in sperm motility and decreased fertility potential. The aim of this study was to determine the optimal concentration of L-cysteine needed for cryopreservation of boar semen. Twelve boars provided semen of proven motility and morphology for this study. The semen was divided into four portions in which the lactose-egg yolk （LEY） extender used to resuspend the centrifuged sperm pellet was supplemented with various concentrations of L-cysteine to reach 0 mmol L^-1 （group Ⅰ, control）, 5 mmol L^-1 （group Ⅱ）, 10 mmol L^-1 （group Ⅲ） and 15 mmol L^-1 （group Ⅳ）. Semen suspensions were loaded in straws （0.5 mL） and placed in a controlled-rate freezer. After cryopreservation, frozen semen samples were thawed and investigated for progressive motility, viability using SYBR-14/EthD-1 staining and acrosome integrity using FITC-PNA/EthD-1 staining. There was a significantly higher （P 〈 0.01） percentage of progressive motility, viability and acrosomal integrity in two L-cysteine-supplemented groups （group Ⅱ and group Ⅲ） compared with the control. There was a biphasic effect of L-cysteine, with the highest percentage of progressive motility, viability and acrosomal integrity in group Ⅲ. In conclusion, 5 or 10 mmol L^-1 was the optimum concentration of L-cysteine to be added to the LEY extender for improving the quality of frozen-thawed boar semen.

Electrochemical investigation on the film of L-cysteine self-assembled to nanoparticles on a gold electrode

The film contained L-cysteine and gold nanoparticles were provided by self-assembled monolayers (SAMs) and potentiostatic electrodeposition technology on the gold electrode. Two methods were used to study the film: In the first, cyclic voltammetry (CV) was used to inspect the functional groups of the film and the same time hydroquinone was chosen to be a probe molecule in the based solution;secondly, based on analytical technology of scanning electrochemical microscopy (SECM), the heterogeneous rate constant (keff) between solid phase (the modified electrode) and liquid phase (K3Fe(CN)6) was obtained. As a result, the better binary catalysis of hydroquinone was demonstrated and the heterogeneous rate constant (keff) is the greater at 8 h for L-cysteine self-assembled monolayers (SAMs).

L-Cysteine-assisted Synthesis of Copper Gallium Sulfide Microspheres

An effective L-cysteine-assisted synthetic route has been successfully developed to prepare copper gallium sulfide（CuGaS2） microspheres under solvothermal conditions with CuCI2.2HzO, GaC13 and L-cysteine as source materials, in which L-cysteine was used as the sulfide source and complexing molecule. The experiments revealed that the synthesized sample was of a typical CuGaS2 tetragonal structure. Moreover, the prepared CuGaS2 crystals consisting of microspheres made up of nanoflakes, and the diameter of the nanoflakes was about 20 nm. Raman spectrum of the obtained CuGaS2 exhibits a high-intensity peak of the A1 mode at 306 cm^-1. Meanwhile, a possible growth mechanism was proposed based on the investigations.

Reparative histogenesis of skin: Reaction on the application of l-cysteine of argentum nitrate gel

The effect of L-cysteine of argentum nitrate gel on the wound process of experimental animals is investigated. The results show that the nanogel, being bacteriostatic, accelerates the course of inflammation phase resulting in fast cleansing of the wound surface and stimulation of the granulation tissue formation. The main cell elements of this tissue—fibroplasts are characterized by the state of functional excitation. The time of wound healing with the use of L-cysteine of argentum nitrate gel was reduced by three days, and the index of wound repair acceleration was about 20%.

Design and fabrication of highly hydrophilic magnetic material by anchoring L-cysteine onto chitosan for efficient enrichment of glycopeptides

Hydrophilic interaction liquid chromatography(HILIC) has been recognized as an effective strategy for glycopeptide enrichment. Hydrophilic materials pave the way to solve the limit of low enrichment capacity and poor selectivity. The present study is the first attempt to combine chitosan(CS) and L-cysteine(L-Cys) to design a novel hydrophilic material focusing on glycopeptide enrichment. CS containing a large number of hydrophilic amino and hydroxyl groups has unique chemical properties, which makes it a very attractive biomaterial for glycopeptide enrichment. The excellent hydrophilicity of zwitterionic molecule L-Cys inspires the idea of anchoring L-Cys onto CS to design a novel hydrophilic material(named as Fe_(3)O_(4)@CS@Au-L-Cys) for the capture of low abundance glycopeptides. To be specific, Au nanoparticles(Au NPs) was introduced into CS-coated Fe_(3)O_(4)via electrostatic interaction and served as bridges to anchor L-Cys onto the surface of CS through strong Au-S bond interaction. The prepared Fe_(3)O_(4)@CS@AuL-Cys exhibited strong affinity, low detection limit(0.5 fmol/μL HRP), high selectivity(HRP/BSA with a molar ratio of 1:1000) for glycopeptides. Moreover, successful application of glycopeptide enrichment in human serum and saliva by Fe_(3)O_(4)@CS@Au-L-Cys was achieved. A satisfactory data set indicates that Fe_(3)O_(4)@CS@Au-L-Cys has promising potential in the application of glycopeptide enrichment in real complex bio-samples and for related glycoproteome research.

Cloning,expression and characterization of L-cysteine desulfhydrase gene from Pseudomonas sp.TS1138

L-cysteine desulfhydrase(CD)plays an impor-tant role in L-cysteine decomposition.To identify the CD gene in Pseudomonas sp.TS1138 and investigate its effect on the L-cysteine biosynthetic pathway,the CD gene was cloned from Pseudomonas sp.TS1138 by polymerase chain reaction(PCR)method.The nucleotide sequence of CD gene was determined to be 1,215 bp,and its homology with other sequences encoding CD was analyzed.Then the CD gene was subcloned into pET-21a(+)vector and expressed in Escherichia coli(E.coli)by isopropyl-β-D-thiogalacto-pyranoside(IPTG)inducement.The recombinant CD was purified by Ni-NTA His-Bind resin,and its activity was identified by the CD activity staining.The enzymatic proper-ties of the recombinant CD were characterized and its critical role involved in the L-cysteine biosynthetic pathway was also discussed.

L-Cysteine inhibits root elongation through auxin/PLETHORA and SCR/SHR pathway in Arabidopsis thaliana

L-Cysteine plays a prominent role in sulfur metabo- lism of plants. However, its role in root development is largely unknown. Here, we report that L-cysteine reduces primary root growth in a dosage-dependent manner. Elevating cellular L-cysteine level by exposing Arabidopsis thaliana seedlings to high L-cysteine, buthionine sulphoximine, or O-acetylserine leads to altered auxin maximum in root tips, the expression of quiescent center cell marker as well as the decrease of the auxin carriers PIN1, PIN2, PIN3, and PIN7 of primary roots. We also show that high L-cysteine significantly reduces the protein level of two sets of stem cell specific transcription factors PLETHORA1/2 and SCR/SHR. However, L-cysteine does not downregulate the transcript level of PiNs, PLTs, or SCR/SHR, suggesting that an uncharacterized post-transcriptional mechanism may regulate the accumulation of PIN, PLT, and SCR/SHR proteins and auxin transport in the root tips. These results suggest that endogenous L-cysteine level acts to maintain root stem cell niche by regulating basal- and auxin-induced expression of PLT1/2 and 5CR/SHR. L-Cysteine may serve as a link between sulfate assimilation and auxin in regulating root growth.

Electrocatalytic determination of L-cysteine using a modified carbon nanotube paste electrode:Application to the analysis of some real samples

The electrooxidation of L-cysteine（L-Cys） was studied using a benzoylferrocene（BF） modified multi-wall carbon nanotube paste electrode（BFCNPE） using cyclic voltammetry（CV）,square wave voltammetry（SWV） and chronoamperometry（CHA）.Under optimum pH in CV the oxidation of L-Cys occurs at a potential about 215 mV less positive than that at the surface of unmodified carbon paste electrode.The catalytic oxidation peak currents were dependent on the L-Cys concentration and a linear calibration curve was obtained in the range 0.7-350.0 mmol/L of L-Cys with SWV method.The detection limit（3s） was determined as 0.1 mmol/L.This method was also used for the determination of L-Cys in some real samples.

Size-controlled green synthesis of silver nanoparticles assisted by L-cysteine

A green and size-controlled synthesis of silver nanoparticles （Ag NPs） in aqueous solution with the assistance of L-cysteine is presented. The size of Ag NPs decreases with the increase of L-cysteine concentration, and thus can be controlled by adjusting L-cysteine concentration. TEM analysis shows that Ag NPs with an average size of 3 nm can be produced in the presence of 1.0 mmol/L L-cysteine, about one sixth of the size of Ag NPs obtained in the absence of L-cysteine （17 nm）. The assynthesized silver colloidal solution is stable and can be stored at room temperature for at least two months without any precipitation. This L-cysteine assisted method is simple, feasible and efficient, and would facilitate the production and application of Ag NPs.

Design ofL-Cysteine Functionalized Au@SiO2@Fe3O4/Nitrogen-doped Graphene Nanocomposite and Its Application in Electrochemical Detection of Pb2＋

A novel magnetic electrochemical sensor was designed for determination of lead ions based on gold na- noparticles（AuNPs）@SiO2@Fe3O4/nitrogen-doped graphene（NG） composites functionalized with L-cysteine. The Au@SiO2@Fe3O4/NG was synthesized by the electrostatic adsorption between AuNPs and SiO2-coated Fe304 NPs（SiO2@Fe304） and the amide bond between Au@SiO2@Fe3O4 and NG. L-Cysteine was successfully functionalized on the surface of Au@SiO2@Fe3O4/NG nanocomposites via the S--Au bond between L-cysteine and AuNPs. Owing to numerous active sites in L-cysteines and high conductivity of Au@SiO2@Fe3O4/NG composites, the pro- posed electrochemical sensor exhibited a well-distributed nanostructure and high responsivity toward Pb（II）. The sensor linearly responded to Pb2＋ concentration in the range of 5-80 μg/L with a detection limit of 0.6 μg/L, indicating that this L-cysteine functionalized Au@SiO2@Fe3O4/NG composite could be a promising candidate material for the detection of Pb2＋.

Enhanced degradation of organic contaminants by Fe(Ⅲ)/peroxymonosulfate process with L-cysteine

The difficulty in Fe(Ⅲ)/Fe(Ⅱ) conversion in the Fe(Ⅲ)/peroxymonosulfate(PMS) process limits its efficiency and application.Herein,L-cysteine(Cys),a green natural organic ligand with reducing capability,was innovatively introduced into Fe(Ⅲ)/PMS to construct an excellent Cys/Fe(Ⅲ)/PMS process.The Cys/Fe(Ⅲ)/PMS process,at room temperature,can degrade a variety of organic contaminants,including dyes,phenolic compounds,and pharmaceuticals.In subsequent experiments with acid orange 7(A07),the AO7 degradation efficiency followed pseudo-first-order kinetic which exhibited an initial "fast stage" and a second "slow stage".The rate constant values ranged depending on the initial Cys,Fe(Ⅲ),PMS,and AO7 concentrations,reaction temperature,and pH values.In addition,the presence of Cl^(-),NO_(3)^(-),and SO_(4)^(2-) had negligible impact while HCO_(3)^(-) and humic acid inhibited the degradation of AO7.Furthermore,radical scavenger experiments and methyl phenyl sulfoxide(PMSO) transformation assay indicated that sulfate radical,hydroxyl radical,and ferryl ion(Fe(Ⅳ)) were the dominant reactive species involved in the Cys/Fe(Ⅲ)/PMS process.Finally,based on the results of gas chromatography-mass spectrometry,several AO7 degradation pathways,including N=N cleavage,hydroxylation,and ring opening were proposed.This study provided a new insight to improve the efficiency of Fe(Ⅲ)/PMS process by accelerating Fe(Ⅲ)/Fe(Ⅱ)cycle with Cys.

A polyoxometalate based electrochemical sensor for efficient detection of L-cysteine

L-cysteine(L-cys),as an important sulfur-containing amino acid,plays an indispensable role in biological systems.Too low and excessively high ratio of L-cys will cause harm to the function of human organs.Therefore,it is very necessary to develop efficient methods to detect it in multifarious samples.This paper has built an electrochemical sensor by combining Keggin-type polyoxometalate(PMo9V3)and cobalt tetrasulfonate(Ⅱ)phthalocyanine(CoTsPc)on indium tin oxide electrodes using the layer-level self-assembly technology for efficiently detection of L-cys.The assembly process and surface morphology of the modified electrode was characterized by ultraviolet–visible spectroscopy,X-ray photoelectron spectroscopy,scanning electron microscope,and atomic force microscopy.The conditions of electro-catalysed oxidation of L-cys were optimized by cyclic voltammetry,and the kinetic electrochemical parameters were also evaluated by electrochemical impedance spectra.Furthermore,the sensing performance of the modified electrode was explored using amperometry.The proposed electrochemical L-cys sensor was found to have superior sensing performance with a range of linear response of 2.5×10^(−7) to 1.7×10^(−4) mol·L^(−1) and 1.7×10^(−4) to 39.5×10^(−4) mol·L^(−1),the detection limit of 1.0×10^(−7) mol·L^(−1)(signal/noise=3),and satisfactory anti-interference ability.Consequently,the fabricated sensor has the potential to be applied in laboratory practices for L-cys deterimination in commercial drinks.

Microwave-assisted synthesis of L-cysteine-capped nickel nanoparticles for catalytic reduction of 4-nitrophenol

A simple and efficient microwave-assisted procedure for synthesis of L-cysteine-capped nickel nanoparticles(cyst-Ni NPs) in ethylene glycol solvent was demonstrated. The as-synthesised NPs were characterised by ultraviolet–visible(UV–Vis) spectrophotometer, Fourier transform infrared(FTIR) spectroscopy, transmission electron microscopy(TEM) and X-ray diffractometry(XRD). The cyst-Ni NPs are proved to be excellent heterogeneous catalysts for the 100% reduction of 4-nitrophenol(4-NPh) in the presence of reductant(Na BH4)within reaction time of 40 s. In contrast, Raney nickel in similar sample environments shows only 25.5% reduction.The kinetic and energetic behaviours of cyst-Ni NPs were also studied, and the reduction reaction is determined to follow pseudo-first-order kinetics with a rate constant value of 0.115 s-1 and activation energy of 36.1 kJ·mol-1. In addition to its high catalytic competence, cyst-Ni NPs catalyst exhibits excellent recyclability with negligible catalytic poisoning.

The miR-9-5p/CXCL11 pathway is a key target of hydrogen sulfide-mediated inhibition of neuroinflammation in hypoxic ischemic brain injury

We previously showed that hydrogen sulfide(H2S)has a neuroprotective effect in the context of hypoxic ischemic brain injury in neonatal mice.However,the precise mechanism underlying the role of H2S in this situation remains unclear.In this study,we used a neonatal mouse model of hypoxic ischemic brain injury and a lipopolysaccharide-stimulated BV2 cell model and found that treatment with L-cysteine,a H2S precursor,attenuated the cerebral infarction and cerebral atrophy induced by hypoxia and ischemia and increased the expression of miR-9-5p and cystathionineβsynthase(a major H2S synthetase in the brain)in the prefrontal cortex.We also found that an miR-9-5p inhibitor blocked the expression of cystathionineβsynthase in the prefrontal cortex in mice with brain injury caused by hypoxia and ischemia.Furthermore,miR-9-5p overexpression increased cystathionine-β-synthase and H2S expression in the injured prefrontal cortex of mice with hypoxic ischemic brain injury.L-cysteine decreased the expression of CXCL11,an miR-9-5p target gene,in the prefrontal cortex of the mouse model and in lipopolysaccharide-stimulated BV-2 cells and increased the levels of proinflammatory cytokines BNIP3,FSTL1,SOCS2 and SOCS5,while treatment with an miR-9-5p inhibitor reversed these changes.These findings suggest that H2S can reduce neuroinflammation in a neonatal mouse model of hypoxic ischemic brain injury through regulating the miR-9-5p/CXCL11 axis and restoringβ-synthase expression,thereby playing a role in reducing neuroinflammation in hypoxic ischemic brain injury.

富含DHA的鸡蛋黄和L-半胱氨酸盐酸盐添加物对冷冻猪精液质量的影响

The objective of the present study was to determine the effects of docosahexaenoic acid （DHA）-enriched hen egg yolks and L-cysteine supplementation on the qualities of the cryopreserved boar semen. A total of 15 ejaculates from 5 Pietrain boars were divided into 4 groups according to the compositions of the freezing extenders used, that is, normal hen egg yolk （group Ⅰ）, DHA-enriched hen egg yolk （group Ⅱ）, normal hen egg yolk with 5 mmol L^-1 of cysteine supplementation （group Ⅲ） and DHA-enriched hen egg yolk with 5 mmol L1 of cysteine supplementation （group Ⅳ）. The semen was cryopreserved using controlled rate freezer and was thawed at 50℃ for 12 s. Progressive motility, sperm viability, acrosome integrity and functional integrity of sperm plasma membrane of the post-thawed semen were evaluated. The supplementation of L-cysteine in the freezing extender alone （group Ⅲ） improved progressive motility （P 〈 0.05）, and the supplementation of L-cysteine in combination with DHA-enriched hen egg yolk （group Ⅳ） improved both progressive motility （P 〈 0.05） and acrosome integrity （P 〈 0.01）. The use of DHA-enriched hen egg yolk alone （group Ⅱ） did not enhance any of the post-thawed semen qualities （P 〉 0.05）. In conclusion, the supplementation of antioxidant L-cysteine alone or in combination with DHA-enriched hen egg yolk significantly improved the post-thawed semen qualities, especially progressive motility and acrosome integrity.

Electrochemical Oxidation of L-Cystenine in SDS/BA/H_2O Microemulsion

The electrochemical oxidation of L-cysteine in an SDS/BA/H_2O microemulsion system was studied with the methods of ultramicroelectrode cyclic voltammetry and AC impedance. The catalytic efficiency of the microemulsion on the electrochemical oxidation increases with the increase of BA or SDS content, but decreases with the increase of the water content because of the effects of BA, SDS and water on the solubilization of L-cysteine in the microemulsion. Furthermore, the catalytic efficiency of the bicontinuous structure is greater than that of an O/W microemulsion system. The results derived from both the rate constant k0 and Gibbs free energy ΔG≠ accord with those from the catalytic efficiency.

Unexpected Synthesis and Crystal Structure of Macrocyclic Nickel Complex Involving Rare S-Cl Bond

A novel complex of [NiL（OOCNH2C2H3SClO3）]·H2O was obtained unexpectedly by the reaction of [Ni（rac-L）]（ClO4）2 with l-cysteine （L=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetra- azacyclotetradecane）, and characterized by EA, IR, ESI-MS and single-crystal X-ray diffraction. It crystallizes in the orthorhombic system, space group P212121 with a=9.211（12）, b=14.942（19）, c=19.002（2）, Mr=563.80, V=2615.3（6）3 , Z=4, Dc=1.432 g/cm3 , F（000）=1204, μ=0.966 mm-1 , the final R=0.0565 and wR=0.1515. The central nickel（Ⅱ） ion displays a distorted six-coordinate octahedral coordination geometry by coordination with four nitrogen atoms of L, and one oxygen and one nitrogen atoms of l-cysteine. The sulfur atom of l-cysteine instead of oxygen atom links directly with the chlorine atom of perchlorate. The title complex is the first example of perchlorate salt involving the sulfur atom.

Synergistic precipitant powered self-assembly of papain for cross-linked enzyme crystals preparation

In this study,we prepared cross-linked enzyme crystals(CLECs)of papain to further broaden the application of the enzyme with high activity in extreme environments.Initially,papain crystals were successfully obtained based on the micro-batch,batch,and expanded batch crystallization experiments.Specifically,ammonium sulfate and polyethylene glycol 6000(PEG6000)were synergistically used as the precipitants,while L-cysteine was applied to enhance the activity of papain.Furthermore,the interaction between L-cysteine and papain was modeled by molecular docking technique.It was found that L-cysteine could form a hydrogen bond with aspartic acid residue(Asp)at site 158,and the electrostatic attraction with lysine residue(Lys)at site 156 was also quite obvious.Then the enzyme crystals were cross-linked by glutaraldehyde at optimized conditions.The papain CLECs were identified by various methods,and it was found that the thermal stability and enzymatic activity both increased compared to the raw enzyme.More importantly,it could be applied at more rigorous conditions,for example,pH of 4.

Hydrogen Sulfide Regulates Ethylene-induced Stomatal Closure in Arabidopsis thaliana

Hydrogen sulfide （H2S） is a newly-discovered signaling molecule in plants and has caused increasing attention in recent years, but its function in stomatal movement is unclear. In plants, H2S is synthesized via cysteine degradation catalyzed by D-/L-cysteine desulfhydrase （D-/L-CDes）. AtD-/L-CDes：：GUS transgenic Arabidopsis thaliana （L.） Heynh. plants were generated and used to investigate gene expression patterns, and results showed that AtD-/L-CDes can be expressed in guard cells. We also determined the subcellular localization of AtD-/L-CDes using transgenic plants of AtD-/L-CDes：：GFP, and the results showed that AtD-CDes and AtL-CDes are located in the chloroplast and in the cytoplasm, respectively. The transcript levels of AtD-CDes and AtL-CDes were affected by the chemicals that cause stomatal closure. Among these factors, ACC, a precursor of ethylene, has the most significant effect, which indicates that the H2S generated from D-/L-CDes may play an important role in ethylene-induced stomatal closure. Meanwhile, H2S synthetic inhibitors significantly inhibited ethylene-induced stomatal closure in Arabidopsis. Ethylene treatment caused an increase of H2S production and of AtD-/L-CDes activity in Arabidopsis leaves. AtD-/L-CDes over-expressing plants exhibited enhanced induction of stomatal closure compared to the wild-type after ethylene treatment; however, the effect was not observed in the Atd-cdes and Atl-cdes mutants. In conclusion, our results suggest that the D-/L-CDes-generated H2S is involved in the regulation of ethylene-induced stomatal closure in Arabidopsis thaliana.

Experimental study of regulatory effect ofhydrogen sulfide on s Flt-1 production in adipocytesthrough ADAM17

Objective To study the effect of hydrogen sulfide on the production of soluble fms-like tyrosine kinase 1(s Flt-1)through a distintegrin and metalloproteinase 17(AD-AM17)in adipocytes.Methods 3T3-L1 cells were cultured and induced to differentiate into adipocytes,then treated with different doses of sodium hydrogen sulfide(NaHS),L-cysteine or transfected with cystathionine-γ-lyase(CSE)siRNA,ADAM17 siRNA or treated with ADAM17 inhibitor,monoclonal antibody.24 hours after treatment,the expression of ADAM17,CSE,and the production of s Flt-1 were determined.Results After the treatment of 10,25,50 nmol/L NaHS or 0.5,1.0,2.0 μmol/L L-cysteine,the expression of ADAM17 and the production of s Flt-1 in adipocytes were significantly decreased,the higher does of L-cysteine and s Flt-1,the lower expression of ADAM 17 and the production of s Flt-1;the effect of 2.0 μmol/L L-cysteine decreasing the expression of ADAM 17 and the production of s Flt-1 were reversed by transfection of CSE siRNA;after the transfection of ADAM17 siRNA and treatment of ADAM17 inhibitor or monoclonal antibody,the production of s Flt-1 in adipocytes were significantly decreased.Conclusion Hydrogen sulfide can reduce the production of s Flt-1 in adipocytes by downregulating the expression of ADAM17.