表面活性剂脂肪醇聚氧乙烯醚对盐藻的毒性研究

以盐藻作为研究对象,研究脂肪醇聚氧乙烯醚（AE）对盐藻的毒性作用。分别使用含有浓度为0、2.5、5.0、10.0、20.0、40.0mg/L AE的营养液培养盐藻,每日记录细胞总数。在实验的第9d,收集藻液并分别对总谷胱甘肽（GSH）、丙二醛（MDA）、过氧化氢（H2O2）、铜-锌超氧化物歧化酶（CuZn-SOD）、可溶性蛋白和叶绿素a含量进行测定。结果表明较高浓度的AE对藻类的生长具有一定的抑制作用;不同浓度的AE处理9d后,各处理组盐藻叶绿素a和T-GSH含量没有显著差异;4.0mg/L AE组盐藻可溶性蛋白含量显著低于对照组和0.25mg/L组（p〈0.05）;0.25mg/L组和4.0mg/L组MDA含量显著低于1.0mg/L组（p〈0.05）;2.0mg/L组和4.0mg/L组盐藻H2O2含量显著低于0.25mg/L组和0.5mg/L（p〈0.05）;AE浓度为0.25mg/L和1.0mg/L组盐藻中CuZn-SOD含量显著低于对照组和0.25mg/L组（p〈0.05）,AE浓度4.0mg/L组盐藻中CuZn-SOD含量显著高于与0.25、0.5、1.0mg/L组（p〈0.05）。证实AE对盐藻具有一定的毒性作用,为活化剂AE的合理使用和安全评价提供了理论依据。     

谷胱甘肽对Cd的解毒机理研究

用原子力显微镜研究还原型谷胱甘肽（GSH）对重金属离子Cd的解毒过程,谷胱甘肽和Cd能迅速形成络合物,此络合物有多个活性点,在汞表面能够迅速生长,在开始的1 min的时间内,谷胱甘肽和Cd的络合物是以平均高度为0.574 nm的单分子层吸附在汞的表面,少量形成底面直径达160 nm,高度达46 nm的组装团。随后2 min,端基是活性组装点,整体以向空间垂直方向组装的模式生长。随后侧基的活性显现,侧基的组装和端基的组装同时进行,GSH-Cd不但向垂直方向长高,还向平面方向铺展,形成厚度达18 nm的铺展层和在铺展层上直径为527 nm,高度为80 nm的大分子组装峰。时间达8 min时,各种分子的作用趋于稳定。重金属离子与谷胱甘肽的多个活性基团作用,轻松实现解毒作用。     

半胱氨酸共存情况下一种快速准确测定谷胱甘肽的新方法

２０～３０ｍ ｍ ｏｌ／ Ｌ 半胱氨酸在 ２ｍ ｉｎ 内可与 φ＝ ０．０３ 甲醛完全反应而被掩蔽。利用谷胱甘肽与 ５,５′二硫代双（２硝基苯甲酸）（ Ｄ Ｔ Ｎ Ｂ）的颜色反应,测定产物在波长 ４１２ｎｍ 的 Ｏ Ｄ 值,通过计算或标准曲线可迅速得出谷胱甘肽含量,误差小于 ２％ 。     

含汞树脂分离提纯谷胱甘肽

对氨基苯汞乙酸连接到聚苯乙烯－二乙类苯截体上，形成含汞树脂，用于提取谷胱甘３肽，其操作吸附容量为每立升树脂吸附谷胱甘肽０．１６ｍｏｌ。ｐＨ影响树脂对谷胱甘肽的吸附，适宜的ｐＨ为３－９。高浓度盐对洗脱有直接的影响。     

电喷雾质谱研究谷胱甘肽与B族维生素的非共价复合物

为了研究谷胱甘肽与水溶性B族维生素的相互作用,采用电喷雾质谱结合紫外光谱,研究具有重要生理功能的谷胱甘肽与B族维生素形成的非共价复合物,B族维生素包括维生素B1(硫胺素),维生素B2(核黄素)和维生素B3(烟酰胺).非共价复合物的合成是将B族维生素和谷胱甘肽按一定化学计量比混合,然后在室温和pH 6～8条件下,将混合物在培养箱内培育60 min,使反应完全.电喷雾质谱表明谷胱甘肽可以与B族维生素形成非共价复合物.串级质谱中的碰撞诱导解离(CID)和紫外光谱进一步确认非共价复合物的生成.     

玉米螟谷胱甘肽转硫酶的纯化及性质研究

以亚洲玉米螟(Ostrinia furnacalis)为材料,经Sephadex-G75、DEAE-Sepharose Fast Flow、还原型谷胱甘肽(GSH)为配基的亲和层析,分离纯化得到玉米螟谷胱甘肽转硫酶(GST)。以2,4-二硝基氯苯(CDNB)为底物测得其比活为1070U/mg蛋白,收率为22.9%,提纯1138倍。经SDS-PAGE和PAGE鉴定,得到的GST为一条带,亚基的分子量为25kD,经凝胶过滤测得其全酶分子量为50kD,说明该酶是由两个相同亚基组成的。IEF测得主带等电点为8.2。该酶最适温度为41℃,最适pH范围为6.3～6.9。经动力学测定该酶双底物反应机制为序列机制,对CDNB的K_m值为0.15mmol/L,对GSH的K_m值为0.35mmol/L,两种底物的k_cat均为783s^-1。Cl-对底物CDNB有竞争性抑制作用,对GSH是非竞争性抑制作用;3,5-二硝基苯甲酸(DNB)对CDNB有竞争性抑制作用,对GSH是反竞争性抑制作用。     

Early effects of copper accumulation on methionine metabolism

Wilson's disease is characterized by longterm hepatic accumulation of copper leading to liver disease with reduction of S-adenosylmethionine synthesis. However, the initial changes in this pathway remain unknown and constitute the objective of the present study. Using the Long Evans Cinnamon rat model, early alterations were detected in the mRNA and protein levels, as well as in the activities of several enzymes of the methionine cycle. Notably, the main change was a redox-mediated 80% decrease in the mRNA levels of the methionine adenosyltransferase regulatory subunit as compared to the control group. Moreover, changes in S-adenosylmethionine, S-adenosylhomocysteine, methionine and glutathione levels were also observed. In addition, in vitro experiments show that copper affects the activity and folding of methionine adenosyltransferase catalytic subunits. Taken together, these observations indicate that early copper accumulation alters methionine metabolism with a pattern distinct from that described previously for other liver diseases.     

过度训练对大鼠心肌线粒体膜和基质游离钙的影响

采用模拟过度训练大鼠模型,观察了大鼠心肌线粒体的MDA、巯基（-SH）、还原型谷胱苷肽（GSH）、磷脂A2（PLA2）、游离钙（Fca2＋）等指标,结果表明：过度训练组大鼠心肌线粒体与对照组相比,-SH含量和GSH含量显著降低（P〈0．01）,PLA2活性显著增加（P〈0．01）;MDA、Fca2＋含量明显升高（P〈0．01）．本文根据以上结果探讨了运动时机体产生的活性氧的氧化过程与过度训练后心肌线粒体膜结构变化以及游离钙之间的关系,提出过度训练后PLA2活性增加可能是其发生机制的关键指标,通过对这一指标的进一步观察能更好地了解过度训练发生的分子机制。     

Tissue-specific expression of glutathione S-transferases induced by 2-tridecanone or quercetin in cotton bollworms, Helicoverpa armigera (Hübner)

The tissue-specific expression of glutathione S-transferases (GSTs) in the cotton bollworm and the expression level induced by 2-tridecanone and quercetin were examined using the methods of biochemistry and the quantitative PCR. The relative expression level of GST mRNA was unanimous with the GSTs activity conjugaging with 1-chloro-2, 4-dimitro-benzene (CDNB) in fat bodies,midguts, heads and integuments of cotton bollworms. The GSTs activity in fat bodies was the highest, then midguts, heads and integuments in turn, which was in consistent with the relative expression level of GST mRNA. The specific activity of GSTs and the relative expression level of GST mRNA could be significantly induced by 2-tridecanone and quercetin, and after the induction the order of the GSTs activity and the relative expression level of GST mRNA in the above four tissues in cotton bollworms was not different from the control.The induction of GSTs by 2-tridecanone was stronger than by quercetin in all four tissues, which was in accordance with the relative expression level of GST mRNA. It suggested that the increase of GSTs activity induced by plant allelochemicals was associated with the elevated expression of GST mRNA in cotton bollworms.     

Nanostructured multilayer thin films of multiwalled carbon nanotubes/gold nanoparticles/glutathione for the electrochemical detection of dopamine

In the present study, multiwalled carbon nanotubes (MWCNTs), gold nanoparticles (AuNPs), and glutathione (GSH) were used to fabricate multilayer nanoscale thin films. The composite thin films were fabricated by layer-by-layer technique as the films were constructed by the alternate deposition of cationic and anionic polyelectrolytes. The MWCNTs were modified via a noncovalent surface modification method using poly(diallydimethylammonium chloride) to form a cationic polyelectrolyte. An anionic polyelectrolyte was prepared by the chemical reduction of HAuCl4 using sodium citrate as both the stabilizing and reducing agent to form anionic AuNPs. GSH was used as an electrocatalyst toward the electro-oxidation of dopamine. The constructed composite electrode exhibits excellent electrocatalytic activity toward dopamine with a short response time and a wide linear range from 1 to 100 μmol/L. The limits of detection and quantitation of dopamine are (0.316±0.081) μmol/L and (1.054±0.081) μmol/L, respectively. The method is satisfactorily applied for the determination of dopamine in plasma and urine samples to obtain the recovery in the range from 97.90% to 105.00%.