309 resultados para Deinagkistrodon acutus
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研究了几种淬灭剂对皖南尖吻蝮蛇蛇毒出血毒素Ⅲ(AaHⅢ)内源荧光的影响。溴代琥珀酰亚胺(NBS)法测得每个AaHⅢ分子中含有3个色氨酸(Trp)残基。实验得到丙烯酰胺(Acr)和I-的碰撞淬灭常数Ksv分别为38.3和4.27L/mol,fa分别为0.96和0.99,Acr和I-均可以淬灭AaHⅢ分子中几乎全部Trp残基的荧光,初步验证Acr与AaHⅢ分子间无明显的相互作用。利用荧光淬灭方法,结合AaHⅢ的荧光发射光谱可以推断,AaHⅢ中的Trp残基较大程度位于分子表面的亲水区。
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Acutohaemolysin, a phospholipase A2 (PLA2) from the venom of the snake Agkistrodon acutus, has been isolated and purified to homogeneity by anion-exchange chromatography on a DEAE-Sepharose column followed by cation-exchange chromatography on a CM-Sepharose column. It is an alkaline protein with an isoelectric point of 10.5 and is comprised of a single polypeptide chain of 13 938 Da. Its N-terminal amino-acid sequence shows very high similarity to Lys49-type PLA2 proteins from other snake venoms. Although its PLA2 enzymatic activity is very low, acutohaemolysin has a strong indirect haemolytic activity and anticoagulant activity. Acutohaemolysin crystals with a diffraction limit of 1.60 Å were obtained by the hanging-drop vapour-diffusion method. The crystals belong to the space group C2, with unit-cell parameters a = 45.30, b = 59.55, c = 46.13 Å, [beta] = 117.69°. The asymmetric unit contains one molecule
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Relata-se a ocorrência de Proleptus acutus Dujardin, 1845 (Nematoda, Physalopteridae) parasitando Zapteryx brevirostris Müller & Henle, 1841 (Rhinobatiformes, Rhinobatidae) em Ubatuba, estado de São Paulo, Brasil. Vinte raias foram analisadas e P. acutus foi encontrado no estômago e intestinos de 14 (70%) animais. Este é o primeiro relato da ocorrência dessa espécie de nematóide em Z. brevirostris no Brasil.
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Food items and nematode parasites were identified from the stomachs of 42 individuals of Phocoena phocoena, 6 of Lagenorhynchus acutus and 8 of L. albirostris stranded off the coastal waters of Northern Scotland between 2004 and 2014. Post-mortem examinations have revealed heavy parasitic worm burdens. Four nematode species complex as Anisakis spp., Contracaeucum spp., Pseudoterronova spp., and Hysterothylacium spp. were recorded. Data on presence of the anisakid species in cetaceans, reported a significative relationship between the presence of Hysterothylacium and the month of host stranding; suggesting a decrease of larval H. aduncum abundance in the period between April and August due to a seasonal effect related to prey availability. Similarly, the parasite burden of the all anisakid genera was related to the year fraction of stranding, and a relationship statistically significant was found just for L. albirostris with an increase between April and October. This finding is explained by a seasonality in occurrence of white-beaked dolphins, with a peak during August, that might be related to movements of shared prey species and competition with other species (Tursiops truncatus). Geographical differences were observed in parasites number of all anisakid species, which was the highest in cetaceans from the East area and lowest in the North coast. The parasites number also increased significantly with the length of the animal and during the year, but with a significant seasonal pattern only for P. phocoena. Regarding diet composition, through a data set consisting of 34 harbour porpoises and 1 Atlantic white-sided dolphins, we found a positive association between parasite number and the cephalopods genus Alloteuthis. This higher level of parasite infection in squid from this area, is probably due to a quantitative distribution of infective forms in squid prey, an abundance of the final host and age or size maturity of squid.
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Mode of access: Internet.
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Elasmobranchs are under increasing pressure from targeted fisheries worldwide, but unregulated bycatch is perhaps their greatest threat. This study tested five elasmobranch bycatch species (Sphyrna lewini, Carcharhinus tilstoni, Carcharhinus amblyrhynchos, Rhizoprionodon acutus, Glyphis glyphis) and one targeted teleost species (Lates calcarifer) to determine whether magnetic fields caused a reaction response and/or change in spatial use of an experimental arena. All elasmobranch species reacted to magnets at distances between 0.26 and 0.58 m at magnetic strengths between 25 and 234 gauss and avoided the area around the magnets. Contrastingly, the teleosts showed no reaction response and congregated around the magnets. The different reactions of the teleosts and elasmobranchs are presumably driven by the presence of ampullae of Lorenzini in the elasmobranchs; different reaction distances between elasmobranch species appeared to correlate with their feeding ecology. Elasmobranchs with a higher reliance on the electroreceptive sense to locate prey reacted to the magnets at the greatest distance, except G. glyphis. Notably, this is the only elasmobranch species tested with a fresh- and saltwater phase in their ecology, which may account for the decreased magnetic sensitivity. The application of magnets worldwide to mitigate the bycatch of elasmobranchs appears promising based on these results.
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Biodiversity of sharks in the tropical Indo-Pacific is high, but species-specific information to assist sustainable resource exploitation is scarce. The null hypothesis of population genetic homogeneity was tested for scalloped hammerhead shark (Sphyrna lewini, n=244) and the milkshark (Rhizoprionodon acutus, n=209) from northern and eastern Australia, using nuclear (S. lewini, eight microsatellite loci; R. acutus, six loci) and mitochondrial gene markers (873 base pairs of NADH dehydrogenase subunit 4). We were unable to reject genetic homogeneity for S. lewini, which was as expected based on previous studies of this species. Less expected were similar results for R. acutus, which is more benthic and less vagile than S. lewini. These features are probably driving the genetic break found between Australian and central Indonesian R. acutus (F-statistics; mtDNA, 0.751 to 0.903; microsatellite loci, 0.038 to 0.047). Our results support the spatially-homogeneous management plan for shark species in Queensland, but caution is advised for species yet to be studied.
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A cabeça lateralmente expandida é a principal sinapomorfia da família Sphyrnidae, a qual compreende todos os tubarões-martelo. Apesar de haver trabalhos abordando esta família, sua anatomia interna tem sido negligenciada como fonte de caracteres para serem utilizados na taxonomia e filogenia dos Sphyrnidae, em especial acerca de seu cefalofólio. Além disso, outros caracteres permanecem pouco estudados na família, tais como os referentes à anatomia dentária, dentículos dérmicos e sistema de poros sensoriais do cefalofólio. As relações filogenéticas entre os Sphyrnidae, e desta família entre os demais Carcharhiniformes, ainda é controversa como sua taxonomia. As poucas hipóteses filogenéticas conhecidas, baseadas em morfologia, não foram testadas sob critérios sistemáticos. Já as poucas hipóteses moleculares existentes foram testadas mas são ainda mais controversas. O presente estudo apresenta uma revisão anatômica e taxonômica dos Sphyrnidae, construindo uma matriz de caracteres mais robusta para testar as relações filogenéticas entre os Sphyrnidae, contando com 3 gêneros relacionados no grupo externo: Carcharhinus, Rhizoprionodon e Negaprion. Os resultados posicionam S. tiburo na base da família, e E. blochii e S. tudes compondo um dos clados mais derivados. Espécies de maior porte e cefalofólio mais expandido compõem um clado formado por S. mokarran + (S. lewini + S. zygaena), ao passo que as de menor porte e com cefalofolio mais arredondado formam um grupo polifilético. Rhizoprionodon acutus aparece como monofilético à família Sphyrnidae quando incluído fora do grupo externo. As árvores de consenso (Strictus, Semi-strictus, Majority-rule e Adams) apresentam os mesmos resultados. Os caracteres cranianos, sensoriais e de dentículo dérmico são os que mais suportaram os diversos clados. Após a revisão taxonômica da família, a filogenia com base em morfologia apresentou-se mais consistente e clara, embora controversa aos dados moleculares.
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本发明涉及一种蛇毒止血酶,属于生化医药技术领域。本发明的纯度为98%以上的蛇毒止血酶是从尖吻蝮(Dienagkistrodon acutus)蛇毒中得到。该酶分子量为31000 道尔顿,由两个亚基组成;其中α-链由135个氨基酸残基组成,β-链由126个氨基酸残基组成。本发明提供了一种新的蛇毒止血酶,它是从福建产尖吻蝮蛇毒中分离纯化得到的单体,具有见效快、作用强的特点,能应用于临床的各种出血疾病的预防和治疗。
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由中国科学院昆明动物研究所肖昌华研究员主持的“注射用尖吻蝮蛇凝血酶”研究项目, 经国家药品监督管理局审查, 符合国家一类新药审批的有关条件, 批准于2003年4月进入Ⅰ期临床实验 (批件号: 2003L01430). 尖吻蝮蛇凝血酶为我国特产的尖吻蝮(Agkistrodon acutus) 蛇毒中分离纯化的蛇毒凝血酶(Hemocoagulase, 止血酵素), 其生理作用与从矛头蝮 (Bothrope jararoca)蛇毒中得到的蛇毒凝血酶 (Hemocoagnalse, Reptilase. Batroxobin)相似, 但化学结构则完全不同, 是一种新型结构的蛇毒止血酶, 属一类生化药品制剂。
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本发明提供一种具有止血功能的尖吻蝮蛇毒凝血酶Ⅰ及其生产方法。经阴离子交换剂柱层析法分离纯化和快速蛋白纯化工作站程序再纯化,本发明从我国特产尖吻蝮(Agkistrodon acutus)的蛇毒中得到纯度在97%以上的尖吻蝮蛇毒凝血酶Ⅰ;经测定,该酶Ⅰ由A、B两个亚基(链)组成,其中,A亚基含有135个氨基酸,B亚基含有126个氨基酸。与现有蛇毒凝血酶(如Reptilase)相比,它是一个全新的新型酶止血剂;经药理、毒理、药代等研究表明,本发明的尖吻蝮蛇毒凝血酶Ⅰ是一个见效快、副作用小、安全有效的新型止血剂。
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本发明经阴离子交换剂柱层析法分离纯化及快速蛋白纯化工作站程序再纯化,从我国特产尖吻蝮(Agkistrodon acutus)蛇毒中得到纯度在97%以上的尖吻蝮蛇毒凝血酶Ⅱ;经测定,该酶Ⅱ由A、B两个亚基(链)组成,其中,A亚基含有125个氨基酸,B亚基含有123个氨基酸;与现有蛇毒凝血酶(如Reptilase)相比,它是一个全新的新型酶止血剂。经药理、毒理、药代等研究表明,它是一个见效快,副作用小的、安全有效的新型止血剂。
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通过Sephadex G-75,DEAE-Sephadex A-50,Sephadex G-200和两次PBE聚焦层析,从尖吻蝮蛇(Dienagkistrodon acutus)蛇毒中纯化到一个分子量为56 000的出血毒素(DaHT-3),经氨基酸组成测定计算,由487个氨基酸残基组成。此成分在SDS-PAGE上显示出一条均一的蛋白染色带,用等电聚焦电泳测定,其pI为5.50。该出血成分的最小出血剂量是2.6#mu#g,具有蛋白水解酶活力,其活力为3.68,但没有精氨酸酯酶和磷脂酶A_(2)活力。用红外光谱仪研究DaHT-3在溶液中酰胺Ⅰ带的吸收谱,该毒素含有31.8%的#alpha#螺旋、56.1%的#beta#折叠和12.1%的转角;当加入EDTA螯合剂去除金属离子后,它们的#alpha#螺旋、#beta#折叠、转角和无规卷曲分别变为11%、26.4%、46.2%和16.5%,而出血活力和蛋白水解酶活力均丧失,表明该出血毒素是金属蛋白酶。
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通过Sephadex-G-100分子筛层析,QAE-Sephadex-A-50阴离子交换层析和两次Poly-buffer-exchanger离子交换层析,分得两个出血毒蛋白,分别称之为HF-1和HF-2。通过碱性PAGE,等电聚焦(IEF),SDS-PAGE和线性密度梯度PAGE,证实两出血蛋白为电泳均一。它们均为三聚体蛋白,分别含有三个相同亚基。HF-1含3 x 113个氨基酸位点,而HF-2含3 x 104个氨基酸位点。EDTA可抑制两者的活性,而碘代乙酸部份抑制HF-2的活性而不抑制HF-1的活性。从氨基酸组成分析发现,HF-1不含有Cys,而HF-1的激光喇曼光谱也没有Cys的特征峰,这在出血毒中是少见的。HF-1和HF-2均属#alpha#-纤溶酶类,同时兼有出血活性和蛋白水解酶活性。还实验了出血HF-2对血小板聚焦的抑制活性,证实HF-2抑制血小板聚集依赖于其对血浆纤原的降解。
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在南大洋生态系统中,桡足类既在初级生产和更高营养级之间起着承上启下的作用,也为大型浮游动物,主要是磷虾生物量年际变化和地区变化提供了很好的缓冲,磷虾存在时它是竞争者和捕食对象,磷虾缺乏时初级生产的转化主要由它承担。国际上对南极桡足类的研究在最近十年进展很快,尤其是生活史策略的研究取得了长足进步。我国对南极磷虾的研究已处于国际先进水平,但对桡足类等小型浮游动物来说却只是刚刚起步。本文利用中国第十三、十五次南极考察的浮游动物标本研了普里兹湾的游游动物群落结构和地理分布。随纬度的不同,普里兹湾存在三种群落类型,62-65°海域是以纽鳃樽为主的北部被囊群落,小型桡足类拟长腹剑水蚤(Oithona similis)和以哲水蚤(Paracalanus spp)在该区域密度最大,最大型的巨锚哲水蚤(Rhincalanus gigas)为该区所特有,并且只有62°S附近出现大量的无节幼体;65-67°S之间是尖角似哲水蚤(Calanoides acutus)和戈氏长腹水蚤(Metridia gerlachei)的分布高峰区,多毛类和毛颚类分布也较多,该地区由磷虾和桡足类交替控制;67°S以南至近岸为近岸群落,是晶磷虾(Euphausia crystallorophias)的分布区域,在我们的调查中由大量的磷虾幼体出现,无节幼体最大密度6000ind·m~(-2),蚤状幼体达到6400ind·m~(-2)。划分北部和中部群落的指示种为纽鳃樽(Salpa thommpsoni)、巨锚哲水蚤和毛颚类;北部和近岸群落的指示种为巨锚哲水蚤、戈氏长腹水蚤和磷虾的蚤状幼体;中部群落和近岸群落之间的指示种是晶磷虾,磷虾的无节幼体和角突隆剑水蚤(Oncaea conifera)作为该区的指示种不是很明显。CHINARE-XV期间进行了桡足类优势种是产卵量培养实验,在调查其间尖角似哲水蚤和戈氏长腹水蚤分别有13.3和5只/雌的产卵量,尖角似哲水蚤表现为明显的双峰态种群结构,早期幼体占据绝大部分,表现为成长种群,CI最早出现在陆冰缘站的冰下推测生殖发生在十月至十一月间。巨锚哲水蚤的无节幼体集中出现于低纬度区,并没有发现有桡足幼体出现。