998 resultados para Snake River


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鱼类主要分布于青藏高原周边, 是一群适合于急流生活的 科鱼类。在独龙江流域7 个点共采 集271 号  鱼类标本(隶属 属、 属和异齿 属) , 结合各采集点数据绘制大鳍异齿 、藏 和扁头 的分布 直方图, 结果显示, 藏 ( E. labiatum) 在流速较快的独龙江下游各采集点的种群数量较上游高, 更适应急流生 境。同时研究了这3 种  鱼类的体长与体重的关系, 参数b (W = aLb) 的范围在218201 和310131 之间, 均为异 速生长; 藏 的生长类型最接近等速生长。

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A new species of the schilbid catfish genus Clupisoma Swainson, 1838, was discovered in the Salween River [= Nujiang] of western Yunnan Province, China. There are no previous records of schilbid catfish from the middle reaches of the Salween River before this discovery. Clupisoma nujiangense, new species, is the ninth species of the genus Clupisoma and only the third schilbid catfish species recorded from China.

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In July 2001, 15 grotesque cyprinid specimens were collected in the Lancangjiang River (of the upper reaches of the Mekong River) in Menglun Town, Xishuanbanna Prefecture, Yunnan Province, PR China. These specimens are characterized by surprising characte

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Labeo victorianus Boulenger, the "ningu", is commercially the most important migratory fish of Lake Victoria, as well as being one of the most abundant of all species landed. Annual catch records of the Fisheries Departments of Uganda, Kenya and Tanzania show that a high yielding seasonal, floating gill net fishery is based on the concentration of sexually mature fish at the river mouths at the time of migration during the bi-annual floods. Migrating fish used also to be caught in high numbers at "kek" barrier traps across the river, as at Hainga on the Nzoia river. Since the heavy exploitation at the river mouth which occurred with the introduction of nylon gill nets in 1956.

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Assessment of common fishery methods and of fish diversity was undertaken in two fishing camps on the Kilombero River in south-eastern Tanzania in surveys towards the end of the dry season, 1994. Fishermen identified 23 different types of fish that they caught on a regular basis. Only 19 species of fish, belonging to 17 genera and 11 families were, however, identified according to Linnean taxonomy. Hooks, nets, traps and spears were used to catch fish. Fish were either sold fresh. or preserved for storage and long-distance tranport by smoking or frying. based un frequency distributions of the numbers of fish landed over a 4 day period at one of the camps, a Shannon-diversity index of 1.95 was calculted. The fork (or total) length of 480 fish and the weight of 413 fish were measured and length frequency distributions as well as length-weight relationships determined for the six most common species. It is concluded that local fishing methods applied in the Kilombero River allow for sustainable fish production.

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This paper highlights the results of a 12 month's ecological study of macrophytes and their role in the economy of the lower Sondu-Miriu river of Lake Victoria. A total of 34 species of aquatic macrophytes were identified. These were grouped as emergent, floating leaved, free floating and submersed. The major community type identified were dominated by Cladium jamaicanse (Crantz) Kurk., Cyperus paprus (L.) and Cyperus latifolius (Poir). The study observed an over dependence on macrophytes by the local community for the supply of bedding, grazing fields, fuel, roofing and other building materials. The white (heart) of Typha shoot, Nile cabbage (Pistia stratiotes and a legume solanum nigrum traditionally known as "osuga" are used as vegetables by local community. The only source of protein in this arid region is the fish caught in the swamps and birds which inhabit the swamp. The swamp provides the only source of green pasture in the dry season for the animals. An export oriented economy has developed involving mat making and basket weaving with exports reaching as far as Japan. The study proposes a rational and sustainable exploitation of the littoral zone to support the adjacent rural community.

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水蛇亚科属于游蛇科,包含10个属。其中7个属为单型属。选取水蛇亚科14个形态学特征进行支序分析,并利用计算机软件Hennig86对水蛇亚科中8个属之间的系统发育关系进行初步探讨,结果显示水蛇亚科分为两支Gerarda和Fordonia两个属构成姊妹群,Cerberus、Erpeton和Homalopsis三个属也构成单系群,与Vorisetal(2002)的分子系统树相同,但Cantoria属的地位则与Vorisetal(2002)的明显不同。

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 在澜沧江下游/ 湄公河上游的滇南西双版纳地区,通过样方法比较了热带雨林的连片与3 个小片断的物 种多样性变化趋势。与连续森林比较,片断热带雨林的植物物种丰富度和物种多样性指数都比较低,而且有相当低 比例的大高位芽、中高位芽和附生等生活型植物,而藤本、小高位芽和矮高位芽等生活型植物的比例则较高;泛热 带、热带亚洲至热带非洲的区系成分比例较高,而当地成分则减少;群落的上层树木比下层树木更加稳定。同样,动 物的物种多样性指数和均衡度在片断热带雨林中都较低,与其密切相关的是片断热带雨林的环境质量,而不是片 断的大小。此外,也探讨了片断热带雨林物种变化与森林小气候的关系,阐明了由凉湿向干暖转化的“林内效应"是 其物种变化的重要原因之一。

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The recent re-emergence of tuberculosis, especially the multidrug-resistant cases, has highlighted the importance of screening effective novel drugs against Mycobacterium tuberculosis. In this study, the in vitro activities of small peptides isolated from snake venom were investigated against multidrug-resistant M. tuberculosis. Minimum inhibitory concentrations (MICs) were determined by the Bactec TB-460 radiometric method. A small peptide with the amino acid sequence ECYRKSDIVTCEPWQKFCYREVTFFPNHPVYLSGCASECTETNSKWCCTTDKCNRARGG (designated as vgf-1) from Naja atra (isolated from Yunnan province of China) venom had in vitro activity against clinically isolated multidrug-resistant strains of M. tuberculosis. The MIC was 8.5 mg/l. The antimycobacterial domain of this 60aa peptide is under investigation. (C) 2003 Elsevier Science B.V. and the International Society of Chemotherapy. All rights reserved.

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L-Amino acid oxidases (LAAOs) are widely distributed in snake venoms, which contribute to the toxicity of venoms. However, LAAO from Bungarus fasciatus (B. fasciatus) snake venom has not been isolated previously. In the present study, LAAO from B. fasciat

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Jerdonitin is a P-II class snake venom metalloproteinase comprising metalloproteinase and disintegrin domains. In this study, we established a high-level expression system in Pichia pastoris and developed a purification strategy for the recombinant Jerdonitin. This recombinant Jerdonitin degraded fibrinogen at a level of activity comparable with its wild type. The effects of recombinant Jerdonitin on inhibiting ADP-induced human platelet aggregation were in a dose-dependent manner with an IC50 of 248 nM. In addition, we reported here that Jerdonitin can significantly inhibit the growth of several cell lines, including human liver cancer cells (Bel7402), human leukemia cells (K562) and human gastric carcinoma cells (BGC823). This study offers recombinant Jerdonitin that will be valuable for further functional and structural studies of Jerdonitin. (C) 2009 Elsevier Ltd. All rights reserved.