细胞色素C在汞表面生长性质的AFM研究——吸附自组装机理

利用原子力显微镜对细胞色素C在汞表面生长过程进行研究,发现细胞色素C在汞表面首先形成的是高度稍大于1nm的吸附单分子层,随着生长时间的增加,吸附在汞表面的细胞色素C分子和溶液中的分子问相互作用,自组装形成生长活性点,生长速度明显加快,生长时间达到8min时,细胞色素C能形成底部直径达527nm,高度达138nm,分布密度约为1．2～2．3个/μm^2的细胞色素C分子集聚体．生长机理是吸附自组装机理．细胞色素C的浓度较大地影响其在Hg表面的自组装平衡,随着浓度的减少,细胞色素C所能形成的最大分子集聚体的高度和数目都随之减少。浓度与平均表现高度是非线性的关系．     

Phylogenetic relationships of Mesobuthus eupeus (C.L. Koch, 1839) inferred from COI sequences (Scorpiones: Buthidae)

In this study, the first molecular phylogenetic analysis of Mesobuthus eupeus in Iran is presented based on sequence data of a ～ 700-base-pair fragment of cytochrome C oxidase, subunit I. Phylogenetic relationships were inferred using parsimony, maximum likelihood and Bayesian inference. The results support monophyly of M. eupeus, but there is a clear divergence between northern and southern clades. The northern clade includes four subspecies – M. e. eupeus, M. e. philippovitschi, M. e. afghanus and M. e. thersites; whereas the southern clade is comprised of two others – M. e. phillipsi and M. e. kirmanensis. Accordingly, possible scenarios for the evolution and phylogeographic structure of M. eupeus based on the geological history of the Iranian Plateau were proposed. The observation of two distinct lineages supports the proposal that M. eupeus might be a species complex composed of species with highly similar morphological features.     

两种细胞色素b5水溶性结构域的性质结构比较

分别将编码牛肝微粒体细胞色素ｂ５水溶性结构域片段Ａ１ａ７－Ａｒｇ８８和Ｓｅｒ５－Ｓｅｒ９７基因在大肠杆菌ＪＭ８３中高效表达，分离纯化后得到Ｔｂ５和Ｌｂ５２种重组野生型蛋白。用核磁共振、紫外可见光谱、圆二色散光谱、循环伏安等方法研究结果表明，Ｌｂ５肽链２端残基未能使蛋白质的血红素周围环境与Ｔｂ５蛋白质Ｎ末端的Ｓｅｒ５和Ｌｙｓ６２个残基所贡献。     

Morphometric and molecular variation in mountain catfishes (Amphiliidae: Amphilius) in Guinea,West Africa

Species of the genus Amphilius are small benthic catfishes that occur throughout tropical Africa and are abundant in the mountain streams of the Fouta Djalon region in Guinea, West Africa. During a 2003 expedition to the area, numerous amphiliid catfish were collected and initial observations revealed a large amount of morphological variation across the sampled basins. These specimens were subjected to a geometric morphometric analysis and standard morphometric analysis. Cytochrome b gene sequences were also obtained and compared among populations. These analyses resulted in the discovery of multiple cryptic taxa within two recognized species, Amphilius platychir and Amphilius rheophilus. The discovery of these taxa is compared with other recent discoveries from the area.     

Cytochrome P450 Monooxygenase Immobilization as a Model of Herbicide Metabolism in vitro

To investigate herbicide metabolism in vitro by cytochrome P450 with stable enzymatic activity, cy-tochrome P450 is immobilized in silk fibroin. The enzymatic activity of immobilized cytochrome P450 is maintained above 80% after repeated batch experiments for 10 times. Moreover, the enzymatic activity of immobilized cytochrome P450 is kept as relatively high as 73.8% after storage for two months at 4℃. In addition, immobilization can improve the temperature and pH stability of cytochrome P450. Immobilized cytochrome P450 has the similar affinity Km values for herbicide chlorsulfuron and triasulfuron as the free cytochrome P450. In the case of chlorosulfuron, affinity Km value is 53μmol/L for free cytochrome P450,and 63μmol/L for immobilized cytochrome P450, respectively. In the case of triasulfuron affinity, Km value is 36μmol/L for free cytochrome P450, and 44μmol/L for immobilized cytochrome P450, respec-tivily. Immobilized cytochrome P450 will be convenient, rapid, stable and continuous for herbicide metabolism in micro-bioreactor in vitro.     

Molecular phylogenetics of Gymnocypris （Teleostei：Cyprinidae） in Lake Qinghai and adjacent drainages

149 complete mitochondrial DNA (mtDNA) cytochrome b (Cyt b) genes (1140 bp) of Gymnocypris przewaiskii, Gymnocypris eckloni and Gymnocypris scolistomus from the Lake Qinghai, Yellow River and Qaidam Basin were sequenced and analyzed. Consistent dendrogram indicated that the samples collected from the same species do not constitute a separate monophyletic group and all the samples were grouped into three highly divergent lineages (A, B and C). Among them, Lineage A contained all samples of G.przewaiskii from the Lake Qinghai and partial samples of the G. eckloni from the Yellow River. Lineage B contained the remaining samples of G. eckloni from the Yellow River.Lineage C was composed of a monophyletic group by G. eckloni from the Qaidam Basin. Analysis of molecular variance (AMOVA) indicated that most of genetic variations were detected within these three mtDNA lineages (93.12%), suggesting that there are three different lineages of Gymnocypris in this region. Our Cyt b sequence data showed that G.przewaiskii was not a polytypic species, and G. scolistomus was neither an independent species nor a subspecies of G.eckloni. The divergent mtDNA lineages of G. eckloni from theYellow River suggested that gene flow between the different populations was restricted to a certain extent by several gorges on the upper reach of the Yellow River. Lineage B of G. eckloni might be the genetic effect from the ancestor which was incorporated with the endemic schizothoracinefishes when the headward erosion of the Yellow Riverreached to its current headwaters of late. The G. eckloni from Basin Qaldam was a monophyletic group (lineage C) and Fst values within G. eckloni from the Yellow River were higher than 0.98, suggesting that the gene flow has been interrupted for a long time and the G. eckloni from Basin Qaidam might have been evolved into different species by ecology segregation. The correlation between the rakers number of Gymnocypris and population genetic variation was not significant.All Gymnocypris populations exhibited a low nucleotide diversity (n=0.00096-0.00485). Therefore the Gymnocypris populations from Basin Qaidam could have experienced severe bottleneck effect in history. Our result suggested Gymnocypris populations of Basin Qaidam should give a high priority in conservation programs.     

用化学发光法检测脂膜的过氧化 Ⅰ.脂质体的自发的和诱发的化学发光

制备了多种类型的脂质体,用化学发光法去测量其上的脂膜过氧化和自由基反应。试验表明:脂质体脂膜的过氧化与介质的温度、pH、pO_2及脂质体的浓度有关,试验过程中应该控制这些因素。用细胞色素C和H_2O_2诱发扩增化学发光时,还应控制反应的时间。脂质体接近于生物膜,是研究脂质过氧化的好材料。用化学发光法测量脂质过氧化和自由基反应,具有灵敏、快速、简便的优点。     

分子筛色谱法快速分离纯化细胞色素C

本法改变了透析法脱盐和离子交换柱层析等传统的分离纯化细胞色素Ｃ的繁琐过程，采用了分子筛色谱法脱盐和纯化．它具有简单、快速及纯度高的特点．     

ED/Au/I-复合物修饰电极在细胞色素C测定中的应用

该文报道了一种采用纳米材料制备修饰电极的新方法，制作了乙二胺/Au溶胶/I^-（ED/Au/I-）复合物修饰的碳纤维微柱电极，并研究了该电极的化学行为。实验结果表明，该微电极对细胞色素C具有良好的催化还原特性，在6.5×10^-7mol/L~1.2×10^-5mol/L浓度范围内，还原峰电流与细胞色素C浓度呈现良好的线性，检测限为3.2×10^-7mol/L；同时，该微电极具有选择性高，体积小和稳定性好等特点，适用于生命科学的研究，为细胞凋亡的病例、药理研究提供了新的数段和方法。     

铅对河南华溪蟹主要组织细胞线粒体标志酶活性的影响

采用毒性实验方法,研究了Pb2 对河南华溪蟹心脏和肝胰腺细胞线粒体标志酶,即单胺氧化酶(MAO)、苹果酸脱氢酶(MDH)和细胞色素氧化酶(CCO)活性的影响.Pb2 处理浓度分别为0.5 mg/L、1 mg/L、5 mg/L、10 mg/L、50 mg/L,实验同时设对照组.分别在24 h、48 h、72 h、96 h进行MAO、MDH、CCO活性的测定.结果显示,随着Pb2 浓度的增加和处理时间的延长,MAO、MDH、CCO的活性基本呈先升后降的趋势,且高浓度组(50 mg/L)表现为明显的抑制作用,剂量-效应和时间-效应关系明显,同时线粒体酶活性的改变有一定的组织差异性,心脏比肝胰腺更敏感.结论:铅可以导致线粒体酶产生明显且不可逆转的损伤;线粒体酶可作为动物受逆境胁迫的生化指标.