关于Gurney公式的强度效应修正

为了使Gurney公式能够在考虑材料强度的前提下预测爆轰驱动速度,采用量纲分析的方法,分析了影响柱壳爆轰驱动的主要因素,建立了抛射速度与主要物理量的函教关系.此函数关系经分离变量后,分别通过理论分析和数值仿真予以确定.分析表明,随着屈服应力的提高,壳体的径向极限速度下降,断裂时间提前.柱壳爆轰驱动的强度效应不容忽略.利用炸药爆速、炸药与柱壳的质量比、柱壳材料的屈服强度和密度等参数,通过拟合公式能够预测柱壳爆轰驱动的极限膨胀速度.

ISOLATION AND PROPERTIES OF A BLOOD-COAGULATION FACTOR-X ACTIVATOR FROM THE VENOM OF KING COBRA (OPHIOPHAGUS HANNAH)

A specific blood coagulation factor X activator was purified from the venom of Ophiophagus hannah by gel filtration and two steps of FPLC Mono-Q column ion-exchange chromatography. It showed a single protein band both in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and alkaline polyacrylamide gel electrophoresis. The mol. wt was estimated to be 62,000 in non-reducing conditions and 64,500 in reducing conditions by SDS-PAGE. The isoelectric point was found to be pH 5.6. The enzyme had weak amidolytic activities toward CBS 65-25, but it showed no activities on S-2266, S-2302, thrombin substrate S-2238, plasmin substrate S-2251 or factor Xa substrate S-2222. It had no arginine esterase activity toward substrate benzoylarginine ethylester (BAEE). The enzyme activated factor X in vitro and the effect was absolutely Ca2+ dependent, with a Hill coefficient of 6.83. It could not activate prothrombin nor had any effect on fibrinogen and thus appeared to act specifically on factor X. The procoagulant activity of the enzyme was almost completely inhibited by serine protease inhibitors like PMSF, TPCK and soybean trypsin inhibitor; partially inhibited by L-cysteine. Metal chelator EDTA did not inhibit its procoagulant activity. These results suggest that the factor X activator from O. hannah venom is a serine protease.

Cloning and purification of alpha-neurotoxins from king cobra (Ophiophagus hannah)

Thirteen complete and three partial cDNA sequences were cloned from the constructed king cobra (Ophiophagus hannah) venom gland cDNA library. Phylogenetic analysis of nucleotide sequences of king cobra with those from other snake venoms revealed that obta

CHARACTERIZATION OF OHS1, AN ARGININE/LYSINE AMIDASE FROM THE VENOM OF KING COBRA (OPHIOPHAGUS HANNAH)

In this paper, we present the results of purification and characterization of an arginine/lysine amidase from the venom of Ophiophagus hannah (OhS1). It was purified by Sephadex G-75 gel filtration and ion-exchange chromatography on DEAE-Sepharose CL-6B. It is a protein of about 43,000, consisting of a single polypeptide chain. It is a minor component in the venom. The purified enzyme was capable of hydrolysing several tripeptidyl-p-nitroanilide substrates having either arginine or lysine as the C-terminal residue. We studied the kinetic parameters of OhS1 on six these chromogenic substrates. OhS1 did not clot fibrinogen. Electrophoresis of fibrinogen degraded with OhS1 revealed the disappearance of the alpha- and beta-chains and the appearance of lower mel. wt fragments. OhS1 had no hemorrhagic activity. It did not hydrolyse casein, nor did it act on blood coagulation factor X, prothrombin and plasminogen. The activity of OhS1 was completely inhibited by NPGB, PMSF, DFP, benzamidine and soybean trypsin inhibitor, suggesting it is a serine protease. Metal chelator (EDTA) had no effect on it.

Three dimensional solution structure of neurotoxin CM-11 from the Ophiophagus hannah

The Ophiophagus hannah (King Cobra) neurotoxin CM-11 is a small protein with 72 amino acid residues, Based on complete assignments of H-1-NMR resonances and determination of secondary structures of CM-11, 349 distance and 27 dihedral angle constraints including 19 phi's and 8 chi's were collected from NOESY and DQF-COSY , and the chemical stereospecific assignment of beta(1)H was partially achieved, Twelve structures with lower energy was obtained via metric matrix distance geometry and refinement with simulated annealing, These structures have a low RMSD of 0.14 nm for backbone atoms and 0.20 nm for heavy atoms, with no distance constraint violation more than 0.05 nm, and no dihedral angle violation more than 3 degrees.

眼镜王蛇泛素融合蛋白基因和核糖体蛋白L30 基因的克隆及分析

从广西产眼镜王蛇( Ophiophagus hannah) 毒腺中抽提总RNA , 经mRNA 纯化后构建眼镜王蛇毒腺 cDNA 文库。从所构建的cDNA 文库中, 随机筛选200 个克隆测序, 得到两个在进化上高度保守的基因: 泛素融 合蛋白基因(GenBank 登录号为AF297036) 和核糖体蛋白L30 基因(GenBank 登录号是AF297033) 。前者cDNA 的开放阅读框为387 bp , 后者为348 bp 。前者编码128 个氨基酸残基组成的泛素融合蛋白前体; 后者编码115 个氨基酸残基组成的核糖体蛋白L30 前体。由cDNA 序列推导出的氨基酸序列分析表明, 泛素融合蛋白前体包 括N - 末端的泛素结构域(76 个氨基酸残基) 和C - 末端的核糖体蛋白L40 结构域(52 个氨基酸残基) 。该蛋 白为一高碱性蛋白, C 末端含有一个“锌指”模式结构。与16 个物种比较的结果表明, 眼镜王蛇与脊椎动物的 泛素融合蛋白氨基酸序列相似度较高, 具有高度的保守性。

Molecular cloning of serine proteases from elapid snake venoms

Serine proteases are widely distributed in viperid snake venoms, but rare in elapid snake venoms. Previously, we have identified a fibrinogenolytic enzyme termed OhS1 from the venom of Ophiophagus hannah. The results indicated that OhS1 might be a serine

Isolation and cloning of a metalloproteinase from king cobra snake venom

A 50 kDa fibrinogenolytic protease, ohagin, from the venom of Ophiophagus hannah was isolated by a combination of gel filtration, ion-exchange and heparin affinity chromatography. Ohagin specifically degraded the alpha-chain of human fibrinogen and the pr

Molecular characterization of L-amino acid oxidase from king cobra venom

An L-amino acid oxidase from Ophiophagus hannah snake venom (Oh-LAAO) was purified by successive gel filtration, ion-exchange and heparin chromatography. Oh-LAAO did not induce platelet aggregation; however, it had potent inhibitory activity on platelet a

Identification and characterization of novel reptile cathelicidins from elapid snakes

Three cDNA sequences coding for elapid cathelicidins were cloned from constructed venom gland cDNA libraries of Naja atra, Bungarus fasciatus and Ophiophagus hannah. The open reading frames of the cloned elapid cathelicidins were all composed of 576 bp an

7 种蛇毒小肽对临床分离耐(多) 药结核分枝杆菌的体外活性研究

目的　检测7 种从蛇毒分离的小肽是否对临床分离的耐药性结核分枝杆菌菌株具有活性。方法　放射性方法检测蛇毒 小肽对结核分枝杆菌的最小抑制浓度,细菌存活计数确证放射性方法的结果。结果　7 种蛇毒小肽对耐药性结核分枝杆菌菌 株都有活性。其MIC 值分别为(μg·mL - 1) : Opiophagus hannah 5. 4 , Naja at ra 8. 6 , B ungarus f asciatus 6. 4 , Trimeresurus ste2 jnegri 12. 6 , Protobothrops mucrosquamatus 11. 8 , Protobothrops jerdonii 7 , A gksist rodon halys 4. 2 。结论　这些结果是首次报 道,为进一步设计和开发新来源的抗结核病新药提供了依据。

中国淡水鱼寄生桡足类鳋科的研究

<正> 一.绪言桡足类的主要组成部分是自由生活的剑水溞(Cyclopoida)和镖水溞(Calanoida),它们都是鱼类的优良食料。另一部分就是营寄生生活的种类,其中有些对于鱼类的危害性很大。鳋科(Ergasilidae)是一群由自由生活的剑水溞演变成寄生生活的过渡类型,其幼虫及雄虫完全营自由生活,只有雌性的成虫始寄生在鱼体上。因此过去如 Gurney氏等认为它们是半寄生性的种类,是很正确的论断。

眼镜王蛇蛇毒金属蛋白酶的分离鉴定和分子克隆

蛇毒金属蛋白酶(SVMPs)被认为是出血性蛇毒中的重要成分，是一个包括多种类 型成员的家族，它们在结构上表现出较大的多样性，有的蛇毒金属蛋白酶除了含有酶结 构以外在羧基端还添加了更多的结构，如：去整合素样结构域、富含半胱氨酸结构域、 外源凝集素结构域，这种结构多样性导致了蛇毒金属蛋白酶生物活性上的多样性。眼镜 蛇科中的蛇毒主要以神经毒为主，对其金属蛋白酶成分的研究比较少，本文以眼镜王蛇 蛇毒中的金属蛋白酶为研究对象，探讨了它的生物活性、结构特点,为我们深入了解蛇 毒金属蛋白酶结构与功能的关系提供了新的研究信息。 首先，通过分子筛凝胶过滤、阴离子交换和肝素亲合层析，我们从梧州产眼镜王 蛇(Ophiophagus hannah)蛇毒中纯化到一个表观分子量为55,000Da 的单链蛋白，测定 了其N 端序列为SQKKDFLEEKKYLELYIVADYVMFR，与其它蛇毒金属蛋白酶的N 端 序列相似性较高，命名为Ohagin。接下来我们研究了该蛋白对纤维蛋白原的作用，发 现Ohagin 能专一性地降解人源纤维蛋白原的α-链，其降解活性能被EDTA 完全抑制， 但不被PMSF 所抑制，说明该蛋白酶为金属蛋白酶。Ohagin 能抑制TMVA 诱导的血小 板聚集，并且这种抑制效应是剂量依赖性的。我们通过cDNA 克隆、蛋白质测序和肽 指纹图谱方法确定了Ohagin 的蛋白质序列，Ohagin 的cDNA 序列编码一个611 氨基酸 长度的开放阅读框，包括信号肽、前肽和成熟蛋白所含有的金属蛋白酶结构域、去整合 素样结构域以及富含半胱氨酸结构域，根据这一结构特点，把Ohagin 归为P-III 型蛇毒 金属蛋白酶。将Ohagin 蛋白质序列与P-Ⅲ型蛇毒金属蛋白酶家族中有代表性的22 种 毒素蛋白序列进行比对和进化树分析后发现Ohagin 与P-Ⅲa 型、P-Ⅲb 型和P-Ⅲc 型 的蛇毒金属蛋白酶的亲缘关系较远，而与眼镜蛇科已知的几种金属蛋白酶亲缘关系较 近，推测它们的生物活性也类似，有可能属于新的P-III 型蛇毒金属蛋白酶亚家族。

眼镜王蛇毒第X因子激活剂结构和功能研究

通过G-75（超细）凝胶过渡，快速蛋白液相色谱（FPLC）阴离子柱两步离子交换从眼镜王蛇毒中分离得到了一个特异的血液凝固第X因子激活剂。在碱性聚丙烯酰胺凝胶电泳和SDS-聚丙烯酰胺凝胶电泳中均呈一条均一的带。纯化的眼镜王蛇毒第X因子激活剂不能作用于纤维蛋白原、凝血酶原、蛋白C、纤溶酶原，对6种人工合成小肽发色底物及BAEE的水解实验表明它不能水解大多数小肽底物，不具备水解BAEE的酯酶活性，表明了它对大分子及小分子底物作用专一性较高，同时表明了对FX的作用是较为专一的。抑制剂研究结果表明它对FX的激活活性被丝氨酸蛋白酶的抑制剂PMSF、TPCK等抑制，而金属离子螯合剂EDTA则无影响，表明眼镜王蛇毒血液凝固第X因子激活剂是一个丝氨酸蛋白酶。