221 resultados para 194-1197B


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介绍了北京奥林匹克森林公园人工湿地系统的设计,跟踪调查了复合垂直流人工湿地在龙型水系水质改善中的功能和效果。复合垂直流人工湿地系统占地面积为41 500 m2,处理水量为2 600 m3/d的污水处理厂尾水(再生水)和20 000 m3/d的主湖循环水。一年多的运行表明,该系统与其他生态工程的协同作用有效地改善了公园内的龙型水系水质,特别是在奥运期间,在保证了奥运主湖水质良好的同时,为运动员和观众提供了优美的休息环境,取得了良好的生态、环境、经济和文化等综合效益。

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本研究利用淡水鲫鱼肝脏为主要原材料提取乙酰胆碱酯酶(acetylcholinesterase,AChE),并设计正交试验确定了鲫鱼肝脏中乙酰胆碱酯酶的最佳提取条件:通过酶抑制法衡量敌敌畏、辛硫磷、三唑磷、乐果等四种不同种类有机磷农药对粗酶液的抑制作用;将鱼肝和鱼脑中乙酰胆碱酯酶活性及蛋白含量的进行对比研究。研究结果表明:提取液pH值、提取液种类以及原料与提取液的质量体积比对酶液的活性影响显著;被测四种有机磷农药中,敌敌畏对AChE活性抑制作用最强。鱼脑的AChE比酶活是肝脏的AChE比酶活的3~7倍。

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麻痹性贝毒是一类水溶性的神经毒素,造成神经细胞电压敏感性钠离子通道(VSSC)高亲和力障碍,与细胞膜离子结合后引起细胞膜内外正常离子的流动失衡,造成膜电位反常,使人瘫痪。麻痹性贝毒的污染及其产毒藻已成为一个受人关注的公共健康问题。综述麻痹性贝毒的理化性质和毒性特点、淡水水体麻痹性贝毒污染及其5种淡水产毒蓝藻,并对淡水中PSP防治工作提出建议。

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我国此前关于光薄甲藻GlenodiniumgymnodiniumPenard在西藏那错湖的记录是基于错误的鉴定,作者在相差显微镜下对标本进行了重新检查,发现此甲藻的细胞壁由多数甲片构成,甲片大小相似,多为六角形,应属于网甲藻属WoloszynskiaThompson的微小网甲藻W.tenuissima(Lauterborn)Thompson。中型四角甲藻TetradiniumintermediumGeitler采于武汉的一小池塘,附着于一鞘藻属Oedogonium植物的丝状体上,属于甲藻门中的不运动种类,

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国家“九五”攻关课题96-008-02-03;中国科学院资源与环境局资助KZ951—A1—102

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中国科学院、武汉市科学技术委员会“晨光计划”和淡水生态及生物技术国家重点实验室资助

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中国科学院分类区系特别支持费资助

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我国产毒微囊藻的新发现──惠氏微囊藻及其毒性的初步研究何家菀,李络平,俞家禄,赵以军,刘永定(中国科学院水生生物研究所,武汉430072)关键词惠氏微囊藻,形态特征,毒性PRELIMINARYSTUDIESONACHINESENEWRECORDOFB...

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UV-B-induced oxidative damage and the protective effect of exopolysaccharides (EPS) in Microcoleus vaginatus, a cyanobacterium isolated from desert crust, were investigated. After being irradiated with UV-B radiation, photosynthetic activity (Fv/Fm), cellular total carbohydrates, EPS and sucrose production of irradiated cells decreased, while reducing sugars, reactive oxygen species (ROS) generation, malondialdehyde (MDA) production and DNA strand breaks increased significantly. However, when pretreated with 100 mg/L exogenous EPS, EPS production in the culture medium of UV-B stressed cells decreased significantly; Fv/Fm, cellular total carbohydrates, reducing sugars and sucrose synthase (SS) activity of irradiated cells increased significantly, while ROS generation, MDA production and DNA strand breaks of irradiated cells decreased significantly. The results suggested that EPS exhibited a significant protective effect on DNA strand breaks and lipid peroxidation by effectively eliminating ROS induced by UV-B radiation in M. vaginatus.

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This is the first experimental study to compare difference in the development of tolerance against toxic Microcystis among multi-species of cladocerans (Daphnia, Moina and Ceriodaphnia) pre-exposed to two M. aeruginosa PCC7820 strains (MC-containing and MC-free). Zooplankton were divided into S population (fed Scenedesmus), M-F population (fed Scenedesmus + MC-free Microcystis), and M-C population (fed Scenedesmus + MC-containing Microcystis). M-F and M-C populations were pre-exposed to Microcystis strains for 4 weeks, and their newborns were collected for experiments. A pre-exposure to MC-containing or MC-free Microcystis increased tolerance against toxic Microcystis. The marked increases in survival rate and median lethal time (LT50, 100-194% increase) in the M-C population of Ceriodaphnia suggest that small-sized cladocerans may develop stronger tolerance against Microcystis than large-sized ones when both groups are exposed to toxic Microcystis. This may explain why dominant Daphnia is usually replaced by small-sized cladocerans when cyanobacteria bloomed in summer in eutrophic lakes. (c) 2005 Elsevier Ltd. All rights reserved.

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A re-examination under the phase contrast microscope of a collection made in a small lake in Xizang, China, which had been previously referred to Glenodinium gymnodinium Penard, has shown that the cell wall is composed of numerous usually hexagonal platelets, and thus the species should be a relatively common member of the genus Woloszynskia, namely W. tenuissima (Lauterborn) Thompson. Tetradinium intermedium Geitler is an immobile species collected from a small pond in Wuhan City, Hubei Province, China. It was attached on filaments of an Oedogonium species. Both genera are newly recorded in China.

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A goose-type lysozyme (g-lysozyme) gene has been cloned from the mandarin fish (Siniperca chuatsi), with its recombinant protein expressed in Escherichia coli. From the first transcription initiation site, the mandarin fish g-lysozyme gene extends 1307 nucleotides to the end of the 3' untranslated region, and it contains 5 exons and 4 introns. The open reading frame of the glysozyme transcript has 582 nucleotides which encode a 194 amino acid peptide. The 5' flanking region of mandarin fish glysozyme gene shows several common transcriptional factor binding sites when compared with that from Japanese flounder (Paralichthys olivaceus). The recombinant mandarin fish g-lysozyme was expressed in E. coli by using pET-32a vector, and the purified recombinant g-lysozyme shows lytic activity against Micrococcus lysodeikticus. (c) 2005 Elsevier B.V All rights reserved.

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Interferon (IFN) exerts its antiviral effect by inducing the expression of a number of IFN-stimulated genes (ISGs) to establish a host antiviral state. Earlier studies identified some important fish IFN system genes from IFN-induced CAB cells (crucian carp Carassius auratus L. embryonic blastulae cells) after treatment with UV-inactivated GCHV (grass carp hemorrhage virus). Herein, the cloning of 2 novel IFN-stimulated genes, termed Gig1 and Gig2, is described for the same cell system. The complete cDNA sequences of Gig1 and Gig2 contain 1244 bp encoding for a 194-amino-acid protein and 693 bp for a 158-amino-acid protein, respectively. A search of public databases revealed that these are 2 novel IFN-stimulated genes, since neither significant homologous genes nor conserved motifs were identified. Active GCHV, UV-inactivated GCHV and CAB IFN-containing supernatant (ICS) induced transcription of these genes and distinct kinetics were observed. An analysis of differences in expression between the 2 genes and the IFN signal factors CaSTAT1 and CaIRF7 indicated that GCHV infection activated different signal pathways for their up-regulation. Upon virus infection, the transcription of Gig1 but not of Gig2 is strongly suppressed by cycloheximide (CHX). In contrast, following treatment with CAB IFN-containing supernatant, CHX does not inhibit either gene transcription. The results suggest that GCHV infection can induce expression of both Gig1 and Gig2 via newly synthesized CAB IFN, most probably through the JAK-STAT signal pathway, and can also directly activate Gig2 transcription without ongoing protein synthesis.