S-Trityl-L-Cysteine诱导HL-60细胞有丝分裂阻滞和凋亡

目的研究S-三苯甲基-L-半胱氨酸(S-Trityl-L-Cysteine,STLC)对急性白血病HL-60细胞有丝分裂阻滞和凋亡的影响,初步探讨药物作用下HL-60细胞有丝分裂阻滞和凋亡间的因果关系。方法将HL-60细胞分成不加药对照组和不同剂量(1、2.5、5、10、50、100μmol/L)STLC加药组,药物作用一定时间后,台盼蓝染色观察HL-60细胞活性变化,MTT法检测其对HL-60细胞的抑制效应,免疫荧光染色观察细胞及其核的特征,流式细胞术分析细胞周期和亚二倍体峰的变化,Annexin-v/PI双染检测药物处理前后正常骨髓细胞凋亡比率。结果MTT和台盼蓝染色实验显示STLC抑制HL-60细胞生长并致其死亡;免疫荧光染色见核破裂及凋亡小体和细胞体积增大等典型有丝分裂灾变细胞凋亡现象;细胞周期和凋亡分析表明STLC致HL-60细胞凋亡比率与药物浓度和作用时间呈正相关,致G2/M期阻滞比率24h和48h随药物浓度增加而升高,而72h无明显变化,进一步研究发现STLC处理早期即可致G2/M期有丝分裂阻滞和凋亡的同时发生,撤除药物作用后有丝分裂阻滞呈可逆性恢复,STLC作用下正常骨髓细胞凋亡比率无明显变化。结论STLC诱导HL-60细胞阻滞在G2/M期并致其凋亡,显示较强的抗有丝分裂和抗肿瘤效果,药物处理早期有丝分裂阻滞和凋亡同时发生提示尚有该药物作用新机制的存在。

Effects of DHA-enriched hen egg yolk and L-cysteine supplementation on quality of cryopreserved boar semen

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.

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.

A potent chemotherapeutic strategy in prostate cancer： S-（methoxytrityl）-L-cysteine, a novel Eg5 inhibitor

Docetaxel-based combination chemotherapy remains the predominant treatment for castration-resistant prostate cancer. However, taxane-related drug resistance and neurotoxicity have prompted us to develop substitute treatment strategies. Eg5 （kinesin spindle protein）, which is crucial for bipolar spindle formation and duplicated chromosome separation during the early phase of mitosis, has emerged as an attractive target for cancer chemotherapy. The aim of this study was to investigate the anticancer efficacy of $-（methoxytrityl）-L-cysteine （S（MeO）TLC）, a novel Eg5 inhibitor in prostate cancer. Eg5 expression was examined in human prostate cancer cell lines and tissue microarrays were constructed from clinical specimens. Antiproliferative activity of S（MeO）TLC in prostate cancer cells was assessed by a cell viability assay. The anticancer effect and inhibitory mechanism of S（MeO）TLC in prostate cancer cells was further explored by Hoechst staining, flow cytometry and immunofluorescence. In addition, the antitumor effect of S（MeO）TLC on subcutaneous xenograft models was assessed. Eg5 expression was identified in PC3, DU145 and LNCaP cells. More than half of prostate cancer clinical specimens displayed Eg5 expression. S（Me0）TLC exhibited more powerful anticancer activity in prostate cancer cells compared with the other four Eg5 inhibitors tested. S（MeO）TLC induced cell death after arresting dividing cells at mitosis with distinct monopolar spindle formation. S（MeO）TLC exhibited its significant inhibitory activity （P〈0.05） on subcutaneous xenograft models also through induction of mitotic arrest. We conclude that Eg5 is a good target for prostate cancer chemotherapy, and S（MeO）TLC is a potent promising anticancer agent in prostate cancer.

Influence of L-Cysteine Concentration on Oxidation-reduction Potential and Biohydrogen Production

The effects of L-cysteine concentration on biohydrogen production by Enterobacterium Bacterium M580 were investigated in batch cultivation.The experimental results showed that L-cysteine could enhance the cell growth,hydrogen production rate and hydrogen yield when its concentration was less than 500 mg·L-1,while it had negative effects when its concentration was higher than 500 mg·L-1.The hydrogen production was the highest 1.29 mol·mol-1(H2/glucose) when 300 mg·L-1L-cysteine was added into the culture,and the yield was 9.4% higher than that in the control.The oxidation-reduction potential(ORP) ,which was influenced by L-cysteine,also affected hydrogen production.The ORP values were in the range-300 mV to-150 mV when the L-cysteine concentration was higher than 500 mg·L-1.Although the ORP in this range was favorable for hydrogen production,it was not suitable for the biomass growth.Hence,less hydrogen was produced.When the L-cysteine concentration was lower than 500 mg·L-1,the ORP was more suitable for both biomass growth and hydrogen production.In addition,at least 91%glucose was consumed when L-cysteine was added to the culture media,compared to the 97.37% consumption without L-cysteine added.

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.

Effect of L-cysteine on bioleaching of Ni-Cu sulphide by A. manzaensis

The effect of L-cysteine in different concentrations on the bioleaching of Ni-Cu sulfide was studied with an extremely thermophilic archaea,Acidianus manzaensis. It is found that adding certain amounts of L-cysteine to the bioleaching system of Ni-Cu sulfide largely enhances the leaching rate. X-ray diffraction (XRD) patterns show the change of bioleached solid residues and the effect of L-cysteine on the surface charges of minerals. Zeta potential and IR spectra of mineral surface show that the interaction between L-cysteine and mineral leads to the formation of metal complex,which is propitious to the bioleaching of Ni-Cu sulfide by Acidianus manzaensis.

Electrocatalytic oxidation behavior of L-cysteine at Pt microparticles modified nanofibrous polyaniline film electrode

Platinum(Pt)/nanofibrous polyaniline(PANI) electrode was prepared by pulse galvanostatic method and characterized by scanning electron microscopy.The electrochemical behavior of L-cysteine at the Pt/nanofibrous PANI electrode was investigated by cyclic voltammetry.The results indicate that the pH value of the solution and the Pt loading of the electrode have great effect on the electrocatalytic property of the Pt /nanofibrous PANI electrode;the suitable Pt loading of the electrode is 600 μg/cm2 and the suitable pH value of the solution is 4.5 for investigating L-cysteine oxidation.The L-cysteine sensor based on the Pt/nanofibrous PANI electrode has a good selectivity,reproducibility and stability.The Pt/nanofibrous PANI electrode is highly sensitive to L-cysteine,and the linear calibration curve for the oxidation of L-cysteine can be observed in the range of 0.2-5.0 mmol/L.

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%.

Hepatic Protective Effects of <i>S</i>-Allyl-L-Cysteine (SAC) in Rats with Carbon Tetrachloride (CCl₄) Induced Liver Injury

S-allyl-L-cysteine (SAC) is an organosulfur compound derived from aged garlic extract (AGE). Studies have reported that AGE possesses bioprotective capacity, including antidiabetic, antimicrobial, antioxidant, and antitumor effects. The present study examined the protective effects of SAC against carbon tetrachloride (CCl4) induced hepatotoxicity in rats. Ten male Wistar rats aged 11 - 12 weeks were randomly divided into two groups (five rats/group) as control and SAC groups. All rats had ad libitum access to water, and the SAC group received water containing SAC intragastrically (200 mg/kg) once daily for five consecutive weeks. In the fifth experimental week, 50% CCl4 in olive oil (1 mL/kg) was administered intraperitoneally three times a week to induce liver injury in both groups. Rats were sacrificed at 24 hours after the last CCl4 injection, and liver tissues were excised for histopathological, immunohistochemical and antioxidant analyses. The rats in the SAC group did not show abnormal behavior, such as decreased water intake or food consumption, during the experimental period. Body weights in all groups did not change significantly over the experimental period. Histopathological analysis showed that the percentage of hepatic steatosis was lower in the SAC group at 12.75% ± 3.74% compared to 24.64% ± 5.29% in the control group (p < 0.05). The percentage of cytochrome P4502E1 (CYP2E1) distribution area in the SAC group was also lower at 19.61% ± 6.18% compared with 25.22% ± 6.21% in the control group (p < 0.05). These results suggest that SAC can alleviate CCl4-induced liver damage by decreasing hepatic steatosis and reducing CYP2E1 expression in rats.

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＋.

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.

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.

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.