989 resultados para RADON 226


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从菜花烙铁头蛇(Trimeresurus jerdonii)的毒腺中提取mRNA,采用RT-PCR技术进行体外扩增,将扩增产物克隆到PMD18-T载体中,最后筛选出一个编码凝集素的基因,命名为TJL。由TJL基因序列推导的氨基酸序列中包含分别由23和135个氨基酸残基组成的信号肽和成熟肽。氨基酸序列比较分析表明,TJL含有半乳糖结合位点和钙离子结合位点,与蝰科蛇互凝集素TSL、PAL、APL和RSL的同源性较高(87.4%~90.4%),与眼镜蛇科蛇互凝集素BML的同源性较低(61.5%)。

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Hundreds of tropical plant species house ant colonies in specialized chambers called domatia. When, in 1873, Richard Spruce likened plant-ants to fleas and asserted that domatia are ant-created galls, he incited a debate that lasted almost a century. Alth

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本发明涉及蛇毒L-氨基酸氧化酶在制备艾滋病治疗药物中的应用,属于生物医学领域。蛇毒L-氨基酸氧化酶可从蝰科或眼镜蛇科毒腺分泌物中分离得到,也可用其编码基因由基因工程表达得到。蛇毒L-氨基酸氧化酶具有显著的抗艾滋病病毒活性,蛇毒L-氨基酸氧化酶可强烈抑制病毒诱导细胞形成合胞体,抑制病毒复制。蛇毒L-氨基酸氧化酶具有活力高(1-3纳摩尔浓度下即可有效抑制HIV病毒),抗HIV病毒的机制与目前所用的逆转录酶抑制剂药物,如AZT,融合阻断药物,如DS不同的特点。另一方面,蛇毒L-氨基酸氧化酶与过氧化氢酶联合应用,可有效降低L-氨基酸氧化酶的细胞毒性,显著提高治疗指数。

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P> Widespread hunting throughout Amazonia threatens the persistence of large primates and other vertebrates. Most studies have used models of limited validity and restricted spatial and temporal scales to assess the sustainability. We use human-demographi

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本发明涉及一种大蹼铃蟾博玛津蛋白及其基因和在制药中的应用,属于生物医学领域。大蹼铃蟾博玛津蛋白是从中国两栖类动物大蹼铃蟾皮肤分泌物中分离得到的一种单链多肽,氨基酸全序列为:NH2GFPIYEIDNRPGCYVDPAERVACAGAGVTKAECKAKGCCFISARRNTIWCFKLKESADAWKCAVPMNTRVACAGAGVTPAECKGKGCCFSSYYGTV WCFKPQE-COOH)编码大蹼铃蟾博玛津蛋白的基因的cDNA由1061个核苷酸组成,编码成熟血小板活化蛋白为第67-378位核苷酸。博玛津具有诱导血小板活化、抑制胃溃疡的作用,可作为血小板聚集诱导剂和制备胃溃疡药物的应用。

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Figs (Moraceae) and their pollinating wasps (Agaonidae) constitute a famous reciprocal mutualism in which figs provide some female flowers for the development of fig wasp offspring while the fig wasps pollinate Fig flowers. However, figs also host many no

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本发明涉及人源性抗菌肽及其衍生物的用途,所述人源性抗菌肽具有选自序列表 SEQ ID NO:1所示的氨基酸序列,还包括此氨基酸序列多肽中个别氨基酸的取代、环化、L-型氨基酸变为D-型氨基酸、缺失或加入而得到的功能等同物。与其它来源碱性抗菌多肽相比,该人源性抗菌肽具有结构简单、人工合成方便、应用于人体无抗原性的有益特点。本发明的人源性抗菌肽及其衍生物具有显著的抑制细菌以及真菌生长的作用,可以应用于制备抗微生物感染制剂。

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In reciprocal mutualism systems, the exploitation events by exploiters might disrupt the reciprocal mutualism, wherein one exploiter species might even exclude other coexisting exploiter species over an evolutionary time frame. What remains unclear is how such a community is maintained. Niche partitioning, or spatial heterogeneity among the mutualists and exploiters, is generally believed to enable stability within a mutualistic system. However, our examination of a reciprocal mutualism between a fig species (Ficus racemosa) and its pollinator wasp (Ceratosolen fusciceps) shows that spatial niche partitioning does not sufficiently prevent exploiters from overexploiting the common resource (i.e., the female flowers), because of the considerable niche overlap between the mutualists and exploiters. In response to an exploiter, our experiment shows that the fig can (1) abort syconia-containing flowers that have been galled by the exploiter, Apocryptophagus testacea, which oviposits before the pollinators do; and (2) retain syconia-containing flowers galled by Apocryptophagus mayri, which oviposit later than pollinators. However, as a result of (2), there is decreased development of adult non-pollinators or pollinator species in syconia that have not been sufficiently pollinated, but not aborted. Such discriminative abortion of figs or reduction in offspring development of exploiters while rewarding cooperative individuals with higher offspring development by the fig will increase the fitness of cooperative pollinating wasps, but decrease the fitness of exploiters. The fig fig wasp interactions are diffusively coevolved, a case in which fig wasps diversify their genotype, phenotype, or behavior as a result of competition between wasps, while figs diverge their strategies to facilitate the evolution of cooperative fig waps or lessen the detrimental behavior by associated fig wasps. In habitats or syconia that suffer overexploitation, discriminative abortion of figs or reduction in the offspring development of exploiters in syconia that are not or not sufficiently pollinated will decrease exploiter fitness and perhaps even drive the population of exploiters to local extinction, enabling the evolution and maintenance of cooperative pollinators through the movement between habitats or syconia (i.e., the metapopulations).

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From the venom of Trimeresurus jerdonii, a distinct thrombin-like enzyme, called jerdonobin. was purified by DEAF A-25 ion-exchange chromatography, Sephadex G-75 gel filtration, and fast protein liquid chromatography (FPLC). SDS-PAGE analysis of this enzyme shows that it consists of a single polypeptide chain with a molecular weight of 38,000. The NH2-terminal amino acid sequence of jerdonobin has great homology with venom thrombin-like enzymes documented. Jerdonobin is able to hydrolyze several chromogenic substrates. The enzyme directly clots fibrinogen with an activity of 217 NIH units/mg, The fibrinopeptides released, identified by HPLC consisted of fibrinopeptide A and a small amount of fibrinopepide B. The activities of the enzyme were inhibited by phenylmethylsulfonyl fluoride (PMSF) and p-nitrophenyl-p-guanidinobenzoate (NPGB). However, metal chelator (EDTA) had no effect on it. indicating it is venom serine protease. (C) 2000 Elsevier Science Ltd. All rights reserved.

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It is known that the diagonal-Schur complements of strictly diagonally dominant matrices are strictly diagonally dominant matrices [J.Z. Liu, Y.Q. Huang, Some properties on Schur complements of H-matrices and diagonally dominant matrices, Linear Algebra Appl. 389 (2004) 365-380], and the same is true for nonsingular H-matrices [J.Z. Liu, J.C. Li, Z.T. Huang, X. Kong, Some properties of Schur complements and diagonal-Schur complements of diagonally dominant matrices, Linear Algebra Appl. 428 (2008) 1009-1030]. In this paper, we research the properties on diagonal-Schur complements of block diagonally dominant matrices and prove that the diagonal-Schur complements of block strictly diagonally dominant matrices are block strictly diagonally dominant matrices, and the same holds for generalized block strictly diagonally dominant matrices. (C) 2010 Elsevier Inc. All rights reserved.

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A phospholipase A(2) (PLA(2)) called jerdoxin, was isolated from Trimeresurus jerdonni snake venom and partially characterized. The protein was purified by three chromatographic steps. SDS-polyacrylamide gel electrophoresis in the presence or absence of dithiothreitol showed that it had a molecular mass of 15 kDa. Jerdoxin had an enzymatic activity of 39.4 mumol/min/mg towards egg yolk phosphatidyl choline (PC). It induced edema in the footpads of mice. In addition, jerdoxin exhibited indirect hemolytic activity. About 97% hemolysis was observed when 2 mug/ml enzyme was incubated for 90 min in the presence of PC and Ca2+. No detectable hemolysis was noticed when PC was not added. Ca2+ was necessary for jerdoxin to exert its hemolytic activity, since only 52% hemolysis was seen when Ca2+ was absent in the reaction mixture. Furthermore, jerdoxin inhibited ADP induced rabbit platelet aggregation and the inhibition was dose dependent with an IC50 of 1.0 muM. The complete amino acid sequence of jerdoxin deduced from cDNA sequence shared high homology with other snake venom PLA(2)s, especially the D49 PLA(2)s. Also, the residues concerned to Ca2+ binding were conserved. This is the first report of cDNA sequence of T jerdonii venom PLA(2). (C) 2002 Elsevier Science Ltd. All rights reserved.

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Explaining "Tragedy of the Commons" of evolution of cooperation remains one of the greatest problems for both biology and social science. Asymmetrical interaction, which is one of the most important characteristics of cooperative system, has not been sufficiently considered in the existing models of the evolution of cooperation. Considering the inequality in the number and payoff between the cooperative actors and recipients in cooperation systems, discriminative density-dependent interference competition will occur in limited dispersal systems. Our model and simulation show that the local but not the global stability of a cooperative interaction can be maintained if the utilization of common resource remains unsaturated, which can be achieved by density-dependent restraint or competition among the cooperative actors. More intense density dependent interference competition among the cooperative actors and the ready availability of the common resource, with a higher intrinsic contribution ratio of a cooperative actor to the recipient, will increase the probability of cooperation. The cooperation between the recipient and the cooperative actors can be transformed into conflict and, it oscillates chaotically with variations of the affecting factors under different environmental or ecological conditions. The higher initial relatedness (i.e. similar to kin or reciprocity relatedness), which is equivalent to intrinsic contribution ratio of a cooperative actor to the recipient, can be selected for by penalizing less cooperative or cheating actors but rewarding cooperative individuals in asymmetric systems. The initial relatedness is a pivot but not the aim of evolution of cooperation. This explains well the direct conflict observed in almost all cooperative systems.

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TMVA, a novel C-type lectin-like protein that induces platelet aggregation in a dose-dependent manner, was purified from the venom of Trimeresurus mucrosquamatus. It consists of two subunits, alpha (15,536 Da) and beta (14,873 Da). The mature amino acid sequences of the a (135 amino acids) and beta subunits (123 amino acids) were deduced from cloned cDNAs. Both of the sequences show great similarity to C-type lectin-like venom proteins, including a carbohydrate recognition domain. The cysteine residues of TMVA are conserved at positions corresponding to those of flavocetin-A and convulxin, including the additional Cys135 in the alpha subunit and Cys3 in the beta subunit. SDS-PAGE, mass spectrometry analysis and amino acid sequence showed that native TMVA exists as two convertible multimers Of (alphabeta)(2) and (alphabeta)(4) with molecular weights of 63,680 and 128,518 Da, respectively. The (alphabeta)(2) complex is stabilized by an interchain disulfide bridge between the two alphabeta-heterodimers, whereas the stabilization of the (alphabeta)(4) complex seems to involve non-covalent interactions between the (alphabeta)(2) complexes. (C) 2002 Elsevier Science Ltd. All rights reserved.

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This work was supported by grants from the National Basic Research Program of China (973 Program, 2007CB411600), the National Natural Science Foundation of China (30621092, 30623007), and Bureau of Science and Technology of Yunnan Province.

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本实用新型为一种阵发性睡眠性血红蛋白尿症诊断试剂盒,主要由盒体(1),盒体(1)内的蛇毒免疫调节因子(SVIRF)(2),配套试剂(3)组成。用于诊断阵发性睡眠性血红蛋白尿症,该试剂盒结构简单,操作方便,诊断准确率高,敏感性好,成本低,对设备要求不高,准确诊断率在92%以上。