A novel short neurotoxin, cobrotoxin c, from monocellate cobra (Naja kaouthia) venom: isolation and purification, primary and secondary structure determination, and tertiary structure modeling

A novel short neurotoxin, cobrotoxin c (CBT C) was isolated from the venom of monocellate cobra (Naja kaouthia) using a combination of ion-exchange chromatography and FPLC. Its primary structure was determined by Edman degradation. CBT C is composed of 61 amino acid residues. It differs from cobrotoxin b (CBT B) by only two amino acid substitutions, Thr/Ala11 and Arg/Thr56, which are not located on the functionally important regions by sequence similarity. However, the LD50 is 0.08 mg/g to mice, i.e. approximately five-fold higher than for CBT B. Strikingly, a structure-function relationship analysis suggests the existence of a functionally important domain on the outside of Loop III of CBT C. The functionally important basic residues on the outside of Loop III might have a pairwise interaction with alpha subunit, instead of gamma or delta subunits of the nicotinic acetylcholine receptor (nAChR). (C) 2002 Elsevier Science Inc. All rights reserved.

Biochemical and biological properties of Trimeresurus jerdonii venom and characterization of a platelet aggregation-inhibiting acidic phospholipase A(2)

Several biochemical and biological activities such as phospholipase A(2), arginine esterase, proteolytic, L-amino acid oxidase, 5'nucleotidase, acetylcholinesterase, thrombin-like, anticoagulant, and hemorrhagic activities were determined for whole desiccated venom of Trimeresurus jerdonii. An acidic phospholipase (named TJ-PLA(2)) was purified by anionic exchange chromatography, gel filtration, and reverse phase HPLC. TJ-PLA(2) had a molecular weight of 16,000 and a pI of 4.8. TJ-PLA(2) was non-lethal to mice up to an i.p. dose of 15 mg/kg body weight and lacked neurotoxicity and myotoxicity. It induced edema in the footpads of mice. The purified enzyme inhibited ADP- and collagen-induced human platelet aggregation in a manner which was both dose- and time-dependent.

一个高活性的孟加拉眼镜蛇毒抗补体因子

用离子交换层析和分子筛从云南南部产的孟加拉眼镜蛇蛇毒中分离到一个高活性的抗补体因子。它表现出较强的体内、体外抗补体活性,其抗补体活性的比活力为1 515u/mg。纯化的抗补体因子在聚丙烯酰胺凝胶电泳中呈现一条带。经SDS-PAGE,确定其全分子量为149kD。还原性SDS-PAGE表明,它由3条多肽链共价结合而成,3条多肽链分子量分别为65.4kD、52.1kD和35.5kD。最小的一条多肽链在还原条件下呈现多态性,一般可见两条带(35.5kD和33.7kD)。过碘酸席夫试剂染色表明,其3条多肽链均含有糖。定量测定表明中性糖含量为1.78%,唾液酸含量为0.38%。其等电点为6.2。对其氨基酸组成分析表明它含有较多的酸性氨基酸。对其3条多肽链的N末端氨基酸序列进行了测定。

湖南烙铁头蛇毒中一个新的舒缓激肤增强肤( TmF)

通过70%冷甲醇抽提、Sephadex C i-15分子筛和反相高效液相色谱G8层析，从湖南产烙铁头蛇毒(Trineresurus muqua nwtus)冻干粉中纯化得到一个新的舒缓激肤增强肤(BPP)，命名为TmF。该小肤的氨基酸序列为p(irr (iy Arg Pro, Leti (iy Pro, Pro, Ile- Pro, Pro ( pau表示焦谷氨酸)。序列结果分析表明，TmF和已经分离得到的BPPs有很高的序列同源性。MSI- MS 测定其分子量为1 .1107 kD o TmF的生物学活性和药理学活性检测的结果表明，它增强舒缓激肤(BK)(1 mg/L)诱导的离体豚 鼠回肠纵行肌收缩的活性为(1 .13士0 .3)单位(mg/ L) ; TmF (5 .0 x 10- 0 mg/ kg)可以增强约(14士2) mmHg的由BK(5 . Ox 10-' mg/ kg)诱导的舒张压下降;在抑制剂试验中，不同剂量的TmF和5x1。一zmg的血管紧张素转化酶保温30 min，结果表明大约 2.0x10一3mg的TmF表现出对ACE水解活性的半数抑制率(IQo )。

随机扩增多态DNA影响因素的研究

随机扩增多态 DNA(PAPD）分析受诸多因素的影响, 作者发现不同厂家制造的 PCR 扩增仪, 不同厂家出品的 TaqDNA 聚合酶和 PCR 缓冲液, PAPD 反应体系中的引物浓度, Mg~(2+)浓度, dNTP 浓度, BSA（牛血清白蛋白）和明胶, 以及模板 DNA的量等均可能对 PAPD 结果有不同程度的影响. 为了使 PAPD 结果在不同实验室间具有重复性和可比性, 提高 PAPD 数据的科学价值, 作者建议在 PAPD 分析过程和文章写作中应规范化. 方法部分, 除一般写明的引物浓度、TaqDNA 聚合酶单位数、dNTP 浓度、每一次 PCR 反应的循环条件和循环数等外, 还应注明 PCR 仪的制造厂家及型号、TaqDNA 聚合酶生产厂家 、PCR 缓冲液的成分、Mg~(2+)浓度, 模板 DNA 浓度等。

Mitochondrial DNA sequence polymorphisms of five ethnic populations from northern China

To study the mitochondrial DNA (mtDNA) polymorphisms in a total of 232 individuals from five ethnic populations (Daur, n=45; Ewenki, n=47; Korean, n=48; Mongolian, n=48; Oroqen, n=44) in northern China, we analyzed the control region sequences and typed for a number of characteristic mutations in coding regions (especially the region 14576-16047), by direct sequencing or restriction-fragment-length-polymorphism (RFLP) analysis. With the exception of 14 individuals belonging to the European-specific haplogroups R2, H, J, and T, the mtDNAs considered could be assigned into the East Asian-specific haplogroups described recently. The polymorphisms in cytochrome b sequence were found to be very informative for defining or supporting the haplogroups status of East Asian mtDNAs in addition to the reported regions 10171-10659 and 14055-14590 in our previous study. The haplogroup distribution frequencies varied in the five ethnic populations, but in general they all harbored a large amount of north-prevalent haplogroups, such as D, G, C, and Z, and thus were in agreement with their ethnohistory of northern origin. The two populations (Ewenki and Oroqen) with small population census also show concordant features in their matrilineal genetic structures, with lower genetic diversities observed.

Multiple maternal origins of chickens: Out of the Asian jungles

Domestic chickens have long been important to human societies for food, religion, entertainment, and decorative uses, yet the origins and phylogeography of chickens through Eurasia remain uncertain. Here, we assessed their origins and phylogeographic hist

Population phylogenomic analysis of mitochondrial DNA in wild boars and domestic pigs revealed multiple domestication events in East Asia

Background: Previously reported evidence indicates that pigs were independently domesticated in multiple places throughout the world. However, a detailed picture of the origin and dispersal of domestic pigs in East Asia has not yet been reported. Results:

Association of prostaglandin-endoperoxide synthase 2 gene polymorphisms with asthma and atopy in Chinese children

Background: Cyclooxygenase-2 (COX-2) plays essential roles in inflammation. Previous studies have suggested associations between prostaglandin-endoperoxide synthase 2 (PTGS2) polymorphisms and prostaglandins production in asthma. Objective: We have invest

Association of pro staglandin-endoperoxide synthase 2 (PTGS2) polymorphisms and Alzheimer's disease in Chinese

Cyclooxygenase-2 (COX-2, encoded by the gene prostaglandin-endoperoxide synthase 2, PTGS2) is a key enzyme in the conversion of arachidonic acid to prostaglandins. The prostaglandins produced by COX-2 are involved in inflammation and pain response in diff

Association of early growth response-1 gene polymorphisms with total IgE and atopy in asthmatic children

Early growth response-1 (Egr-1) is expressed in human airways and found to modulate tumor necrosis factor, immunoglobulin E (IgE), airway responsiveness, and interleukin-13-induced inflammation in mice. We investigated the effects of Chinese-tagging singl

Structural analysis of human CCR2b and primate CCR2b by molecular modeling and molecular dynamics simulation

CCR2b, a chemokine receptor for MCP-1, -2, -3, -4, plays an important role in a variety of diseases involving infection, inflammation, and/or injury, as well as being a coreceptor for HIV-1 infection. Two models of human CCR2b (hCCR2b) were generated by h

The dazzling array of basal branches in the mtDNA macrohaplogroup M from India as inferred from complete genomes

Many efforts based on complete mitochondrial DNA (mtDNA) genomes have been made to depict the global mtDNA landscape, but the phylogeny of Indian macrohaplogroup M has not yet been resolved in detail. To fill this lacuna, we took the same strategy as in o