L-半胱氨酸改性甲基纤维素自愈合水凝胶的制备及其性能研究

以甲基纤维素(MC)为水凝胶主体,通过Steglich酯化反应将L-半胱氨酸(Cys)接枝在MC上,从而引入巯基形成动态的二硫键,合成增强型自愈合水凝胶MC-Cys。采用傅里叶变换红外光谱仪、扫描电子显微镜、核磁共振氢谱仪、流变仪、热重分析仪等对水凝胶的结构和性能进行表征。结果表明,MC-Cys水凝胶的最大拉伸强度能达到1.251MPa,比纯MC水凝胶拉伸强度(0.626MPa)提高了1倍,动态的二硫键赋予了MC-Cys水凝胶自愈合性,在生物医学、组织工程等领域应用前景广阔。

L-半胱氨酸对绵羊卵巢颗粒细胞增殖、凋亡和类固醇激素分泌的影响

旨在探讨L-半胱氨酸(L-Cys)对体外培养绵羊卵巢颗粒细胞(GCs)增殖、凋亡和类固醇分泌的影响。本研究采集1~1.5岁龄体重相近饲养条件相同的30只健康性成熟小尾寒羊母羊新鲜卵巢,从优势卵泡(2~8 mm)中收集GCs,随机分为5组,每组6个重复,各组添加L-Cys浓度分别为0、100、300、500和700μmol·L^(-1),培养48 h后用CCK-8试剂盒进行细胞增殖活力测定,Annexin V-FITC/PI流式细胞仪检测GCs的凋亡情况,采用ELISA检测GCs培养液上清中孕酮和雌二醇的分泌水平并采用实时荧光定量PCR和Western blot分析L-Cys对绵羊颗粒细胞增殖相关基因(PCNA、CCND2、CCNB 1)、凋亡相关基因(BAX、Caspase-3、Bcl-2)和类固醇分泌相关基因的(STAR、3β-HSD、CYP 11A1、CYP 19A1)mRNA和蛋白表达的影响。结果显示,100、300和500μmol·L^(-1)组的L-Cys均可显著促进绵羊GCs的增殖活力(P<0.05),并显著抑制其凋亡率(P<0.05)。添加300μmol·L^(-1)的L-Cys显著抑制了孕酮(P 4,P<0.05)的分泌。进一步研究发现,300μmol·L^(-1)和500μmol·L^(-1)组的L-Cys可以上调增殖相关基因(PCNA、CCND2、CCNB 1)mRNA表达水平,其中300μmol·L^(-1)组的增殖蛋白(PCNA、CCND2、CCNB1)表达量显著上升(P<0.05);100μmol·L^(-1)和300μmol·L^(-1)组显著下调凋亡相关基因(BAX、Caspase-3)mRNA(P<0.05)及其蛋白表达水平(P<0.05)。添加300μmol·L^(-1)L-Cys显著降低了类固醇相关基因(STAR、3β-HSD)mRNA及蛋白表达水平(P<0.05),添加100μmol·L^(-1)和300μmol·L^(-1)L-Cys显著升高了类固醇相关基因(CYP 11A1、CYP 19A1)mRNA(P<0.05)及其蛋白表达水平(P<0.05)。综上,L-Cys通过上调基因PCNA、CCNB1、CCND2、Bcl-2 mRNA及其蛋白表达、下调基因BAX、Caspase-3 mRNA及其蛋白表达,促进绵羊GCs增殖,抑制其凋亡;L-Cys通过下调基因STAR、3β-HSD mRNA及其蛋白表达以及上调基因CYP 11A1 mRNA及其蛋白表达抑制P 4的分泌。

大蒜辣素在大鼠体内转化产物S-烯丙基巯基-L-半胱氨酸的鉴别

目的鉴别大鼠给药后大蒜辣素体内转化产物S-烯丙基巯基-L-半胱氨酸,探讨血浆和皮肤组织中S-烯丙基巯基-L-半胱氨酸的变化情况。方法取SD大鼠,雌雄各半,体重(200±20)g,随机分为8组,分别为空白组及给药后不同时间组,每组每个时间点采用6只大鼠,涂抹大蒜软膏于大鼠背部,分别于0、5、10、15、20、25、30、60 min依次取血液和皮肤组织,UPLC-MS/MS鉴定血液和皮肤组织中大蒜辣素的转化产物S-烯丙基巯基-L-半胱氨酸及变化情况。结果大蒜辣素与半胱氨酸反应产生S-烯丙基巯基-L-半胱氨酸,30 min即可反应90%以上。血浆中转化产物S-烯丙基巯基-L-半胱氨酸在4 h内稳定。UPLC-MS/MS鉴定并确定了皮肤组织和血浆样品大蒜辣素与内源性半胱氨酸的反应产物S-烯丙基巯基-L-半胱氨酸,给予大蒜软膏30 min内血浆和皮肤中S-烯丙基巯基-L-半胱氨酸的浓度逐步增大,60 min时含量降低。结论大蒜辣素可与血浆和组织中的内源性半胱氨酸快速反应,本研究将为大蒜辣素的后续研究提供重要依据。

L-半胱氨酸处理铜基吸液芯亲水工艺与机理研究

目的研究L-半胱氨酸浸渍处理工艺对铜基表面亲水性能的影响,并采用获得的最优工艺处理吸液芯来实现表面改性,提高吸液芯毛细能力,从而优化均热板的传热效率。方法设置温度、时间、浓度进行三因素五水平正交实验;利用接触角测量仪测定测试样品与水之间的接触角;使用相同时间内水在吸液芯层垂直爬升高度来表征毛细攀升能力;用扫描电子显微镜(SEM)观察处理前后吸液芯微观形貌,用能谱仪(EDS)研究吸液芯处理前后表面元素变化情况,用X射线光电子能谱(XPS)研究处理前后吸液芯表面元素价态变化,用测温平台测量处理前后吸液芯制成的均热板热阻。结果正交实验反映了浓度、时间、温度对处理后的铜板与水的接触角影响力,浓度最高,温度最低;L-半胱氨酸处理后的吸液芯毛细能力提高了约40%;吸液芯处理前后的微观形貌发生显著变化;XPS显示S峰结合能向低结合能方向发生偏移,部分铜由1价转化成2价;处理后的试样在相同功率条件下,与处理前相比,在传热效率方面表现出显著的温差优势,其极限传热功率提升约200 W。结论L-半胱氨酸浸渍处理铜基能明显提高铜表面亲水性,使用最佳工艺能够提高均热板吸液芯的毛细能力,从而提高均热板的传热性能。

NPCl-CDs/Fe^(3+)荧光探针的制备及对L-Cys的传感检测

以葡萄糖、乙二胺、浓盐酸和浓磷酸作为反应前体,采用一步水热法合成了一种蓝绿色的荧光碳点NPCl-CDs,并以此构建了NPCl-CDs/Fe^(3+)荧光探针用于实际样品中L-半胱氨酸(L-Cys)的定量检测.实验结果表明,在NPCl-CDs中加入Fe^(3+)可使NPCl-CDs的荧光猝灭,当向NPCl-CDs/Fe^(3+)猝灭体系中引入L-Cys时,体系的荧光强度得以恢复.由此构建了一种用于L-Cys定量检测的新型“开-关-开”NPCl-CDs/Fe^(3+)-L-Cys荧光传感系统.该方法在5.8~60.0μmol/L浓度范围内呈现较宽的线性区域,检出限为0.052μmol/L.该荧光传感系统对L-Cys表现出良好的选择性,对实际样品中L-Cys的检测具有潜在的应用价值.

基于Co-MOFs衍生物用于L-Cys的比色和智能手机双模检测

采用室温合成-热解法制备了一种具有类过氧化物酶性质的金属钴有机框架衍生纤维棒状碳材料(Co-DM)。利用SEM、TEM、XRD和XPS对其形貌、结构及元素组成进行了表征。通过活性氧捕获实验研究了其催化机理,Co-DM可催化H2O2使其释放出超氧阴离子自由基(·O_(2)^(-))和羟基自由基(·OH),从而使无色的显色底物3,3’,5,5’-四甲基联苯胺(TMB)氧化成蓝色的氧化态产物(ox TMB),在652 nm处有最大的紫外吸收峰;而L-半胱氨酸(L-Cys)具有抗氧化性,能够还原ox TMB使蓝色褪色。基于此原理建立了一种检测L-Cys的比色检测方法。在pH=4.0、温度为40℃的最优条件下,L-Cys的浓度与652 nm处的吸光度在0.1~15.0μmol/L范围呈线性关系,检出限(LOD)为0.35μmol/L。此外,借助自制的智能手机光学设备和Color Garb软件,通过记录不同浓度L-Cys下溶液在白色(0,0,0)至黑色(255,255,255)范围内颜色变化的特征值R(红)、G(绿)、B(蓝)值,建立了Co-DM的相对活性与颜色特征值的定量关系,检测范围为0.1~70.0μmol/L,LOD为0.27μmol/L。该方法还成功地应用于临床人血清中L-Cys的检测,回收率在94.0%~101.5%之间。

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。

L-半胱氨酸对揭竹过程中腐竹品质的影响

在腐竹制作过程中添加不同浓度的L-半胱氨酸,替代亚硫酸盐类漂白剂用于改善腐竹色泽,并进一步研究其对揭竹过程中腐竹的成膜速率、产率、蒸煮损失率、机械特性、营养组成及感官品质的影响,为传统豆制品腐竹的质量提高和科学化生产提供理论依据。结果表明,L-半胱氨酸添加量为0.05%时腐竹的成膜速率及总产率最高,蒸煮损失率较小。添加量0.25%时,腐竹的L*值最大、机械特性以及感官得分最高,同时可以显著提高腐竹的成膜速率及产率。

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.

L-半胱氨酸/蛋白酶对羊毛防缩整理效果研究

羊毛纤维是纺织工业中重要的生产原材料,但其固有的缩绒性会严重影响产品的使用性能和寿命,因此防缩整理是毛纺加工中必不可少的工艺流程。文中利用还原试剂L-半胱氨酸和蛋白酶16L的协同作用,对羊毛毛条进行防缩整理,探讨了整理效果、最优工艺及整理后羊毛纤维的性能变化。通过设计响应面试验,获得最优防缩工艺条件为:L-半胱氨酸浓度9 g/L、蛋白酶浓度1 g/L、浸轧时间30 s、浸轧次数5次、处理温度50℃。经该工艺处理后,羊毛纤维的各项重要性能未受到明显破坏,防缩性能得到显著改善。

N-乙酰-L-半胱氨酸抗1型糖尿病模型比格犬晶状体上皮氧化损伤的作用

本研究旨在探讨N-乙酰-L-半胱氨酸(NAC)对1型糖尿病模型比格犬晶状体上皮氧化损伤的影响。将40只2~3岁比格犬随机分为对照组(CON组)、糖尿病模型组(DM组)、胰岛素治疗组(INS组)、NAC联合胰岛素治疗组(NAC+INS组)和NAC治疗组(NAC组),每组8只,各治疗组试验犬模型建立持续120 d。在造模前及造模后按试验设定时间对犬进行空腹血糖监测、胰岛素释放试验、房水葡萄糖测定、用裂隙灯进行白内障等级评定。对眼晶状体上皮进行病理组织学观察的同时,利用ELISA、RT-PCR等方法对晶状体内氧化应激指标进行检测。试验结果显示:空腹血糖监测和胰岛素释放试验显示,成功建立了1型糖尿病比格犬模型;与CON组相比,DM组犬在试验结束时,血清及房水葡萄糖显著升高(P<0.05),晶状体功能明显下降;裂隙灯结果显示,DM组犬的晶状体混浊等级在试验结束时达Ⅳ级,其余4组并未出现明显皮质混浊迹象,且DM组的晶状体上皮出现细胞核固缩和坏死小体等较为明显的病理变化;NAC、INS和NAC+INS组血糖虽呈下降趋势,但仍高于CON组,其中,NAC+INS组血糖较DM组显著下降(P<0.05),晶状体混浊也明显改善;试验结束时,与CON组相比,DM组犬晶体上皮和房水MDA含量升高(P<0.05或P<0.01),GSH-Px活性和GSH/GSSG均显著下降(P<0.05或P<0.01),GR活性下降(晶状体上皮,P>0.05;房水,P<0.01),给予NAC联合胰岛素治疗后,晶体上皮内的氧化应激标志物均出现相反趋势;DM组及各治疗组中抗氧化相关基因SOD2和GR表达量均显著升高(P<0.05)。综上:NAC联合胰岛素治疗能有效改善糖尿病犬的血糖和晶状体功能,NAC联合胰岛素治疗后对糖尿病犬晶状体上皮损伤的保护作用可能和抑制晶状体的氧化应激有关。

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.

L-半胱氨酸和聚吡咯功能化磁性高岭土对水中Hg^(2+)的吸附

为提高高岭土对水中Hg^(2+)的吸附能力并改善其团聚性能,采用一种安全、高效、绿色的方法合成了L-半胱氨酸和聚吡咯双功能化的磁性高岭土(m@Kaolin-LC/Ppy)。通过扫描电镜、傅里叶红外、X射线衍射仪、比表面积分析仪和磁强计等对吸附剂进行表征,分析了m@Kaolin-LC/Ppy合成前后的各项参数,同时研究了不同pH和反应温度下对水中Hg^(2+)的去除情况。结果表明:m@Kaolin-LC/Ppy在pH=7和投加量为0.05 g/L的条件下取得最佳吸附量372.5 mg/g,对Hg^(2+)的去除过程符合准二级动力学和Langmuir等温吸附,并以化学吸附为主。m@Kaolin-LC/Ppy具有较好的重复使用性、良好的分散能力和化学稳定性,吸附后易于从水中分离出来。

叶面喷施S-烯丙基-L-半胱氨酸对水稻砷转运影响机制

膳食稻米是我国人群摄入高致癌风险无机砷(iAs)的主要来源,开发降低稻米砷(As)含量生产措施对保护人体健康具有重要意义。本文以我国南方主栽水稻品种“中早35”为试验材料,采用盆栽试验研究了开花期叶面喷施S-烯丙基-L-半胱氨酸(SAC)对水稻籽粒和营养器官中总As含量的影响并揭示其潜在的分子机制。结果表明:当SAC喷施浓度达到0.2 mmol·L^(-1)时籽粒和根中总As含量分别显著降低42.3%和20.6%,但旗叶中总As含量显著增加了72.4%;荧光染色观察试验表明旗叶中H_(2)O_(2)含量显著降低,同时SOD和CAT酶活性分别显著升高61.8%和105.3%。喷施SAC后水稻顶端第一节中Lsi6转运子编码基因以及Lsi3转运子编码基因分别显著下调59.8%和36.3%,据此推测喷施SAC可能显著降低了水稻从通向旗叶膨大维管束流中卸载As^(Ⅲ)和向连接稻穗弥散维管束装载As^(Ⅲ)的能力,导致籽粒中总As含量显著降低而旗叶中总As含量显著升高。旗叶植物螯合素(PCs)合成酶OsPCS1和负责向细胞液泡中转运As^(Ⅲ)的OsABCC1转运子编码基因分别显著上调57.6%和61.0%,表明喷施SAC增加了旗叶合成PCs并向液泡中区隔As^(Ⅲ)的能力从而降低了叶片的As^(Ⅲ)胁迫。水稻根部Lsi1、Lsi2、Lsi3转运子编码基因分别显著下调了27.2%、23.8%、29.5%,表明水稻根部对As^(Ⅲ)的吸收、转运能力降低,同时可能也预示着As^(Ⅲ)向木质部导管中装载As^(Ⅲ)的能力降低。综上,喷施SAC通过调控As^(Ⅲ)转运子编码基因表达降低了水稻籽粒和根中总As含量,同时缓解了As胁迫。

谷氨酸棒杆菌中L-半胱氨酸外排蛋白的鉴定及应用

L-半胱氨酸是一种重要的含硫氨基酸,被广泛应用于食品,医药,化妆品等行业。有效的外排蛋白不仅可以降低反馈抑制和细胞毒性,还能提高菌体的生产能力。在细胞工厂的构建中发挥重要作用。该研究基于转录组测序分析,在谷氨酸棒杆菌中发现一种新的L-半胱氨酸外排蛋白Cg1298-Cg1299。当添加7.5 mmol/L L-半胱氨酸时,cg1298-cg1299缺失菌株的生长比对照菌株降低了约24.2%,而回补菌株恢复了对半胱氨酸的抗性。利用Cys-Tyr二肽进一步检测Cg1298-Cg1299对半胱氨酸的外排能力,发现cg1298-cg1299双敲菌株的L-半胱氨酸外排能力下降了26.3%。最后,在L-半胱氨酸底盘菌中过表达cg1298-cg1299使得L-半胱氨酸产量提高17.1%。综上所述,Cg1298-Cg1299是谷氨酸棒杆菌中一种新的L-半胱氨酸外排蛋白,其显著增强了谷氨酸棒杆菌对L-半胱氨酸的耐受性,并提高了L-半胱氨酸的生产能力,为将来构建高产L-半胱氨酸的细胞工厂提供了一个有效靶点。

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).

NH_(2)MIL与半胱氨酸的相互作用及其荧光传感应用

为研究L-半胱氨酸(L-Cys)的荧光检测方法,先将Fe^(3+)和2-氨基对苯二甲酸(NH_(2)BDC)通过水热法聚合制备结晶纳米配位聚合物NH_(2)MIL,再利用NH_(2)MIL中的Fe^(3+)和L-Cys中巯基之间的氧化还原反应使NH_(2)MIL解聚,释放配体NH_(2)BDC,通过对NH_(2)BDC的荧光检测实现L-Cys检测.实验结果表明,悬浮液中L-Cys的浓度和NH_(2)MIL悬浮液的荧光发射强度在10~200 nmol·L^(-1)浓度范围内呈良好的线性关系,R^(2)=0.999 1,检测限达1.78 nmol·L^(-1),且该检测方法对L-Cys有较强的选择性和抗干扰能力,具有一定的使用前景.

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.

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.