989 resultados para 3C 273


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长江三峡水库蓄水后 ,香溪河水环境条件将发生变化 ,也导致该流域内重金属环境化学行为的变化 ,有些金属的危害比现在会更大。为积累蓄水前的基本资料 ,在 1996~ 1997年春、夏、秋、冬四季采集了香溪河原水、沉积物、鱼类和植物样品 ,并对所采集的鱼进行分类 ,分析这些样品中的Ca、Mg、As、Pb、Cd、Cr、Cu、Hg和Zn元素的含量。研究结果显示 ,香溪河局部地区因小金矿开发引起的Hg污染十分严重 ;洪水期 (7月 )原水中的Pb、Cd、Cr、Cu浓度大于枯水期 (1月 ) ;沉积物中Pb、Cd浓度

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利用全能量收支同步测定呼吸仪系统测定了三种不同蛋白源 (鱼粉、豆粕、土豆蛋白 )饲料对银鲫生长及能量收支各组分的影响。对照饲料全部以鱼粉为蛋白源 ,另两种饲料中3 0 %的蛋白质分别来自豆粕和土豆蛋白。试验结果表明 ,银鲫对三种蛋白源的饲料的摄食率 ,食物转化效率均有显著差异 ,以鱼粉组最高 ,豆粕其次 ,土豆蛋白最低。能量收支各组分也均有显著差异 ,能量收支式如下 :鱼粉  88 1C =1 3 77F +2 95U +2 4 1G +41 8R豆粕  1 0 2 3C =1 7 1F +2 8U +1

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国家自然科学基金资助项目(39970587; 香港特别行政区研究资助局研究项目(CUHK4062/98M); 香港中文大学博士后

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应用群体累积培养法 ,研究了种群起始密度对萼花臂尾轮虫休眠卵的形成及与之相关的混交雌体百分率和受精率的影响 .结果表明 ,在连续 11d的培养中 ,轮虫休眠卵的产量和形成效率以及种群中的平均混交雌体百分率以种群起始密度为 1 0~ 10 0ind·ml-1组最大 ,2 0 0ind·ml-1组次之 ,5 0 0ind·ml-1组最小 .各组间的平均混交雌体受精率则无显著差异 .对轮虫休眠卵最大形成效率及其出现的时间以及到达此时休眠卵产量的统计分析结果显示 ,在进行休眠卵的规模化生产时 ,宜选择种群起始密度

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对室养条件下20尾雌性稀有 鲫的产卵频次、成熟卵巢卵径分布及卵子补充过程进行了研究。产卵间隔中卵径分布呈现不同的峰值,卵母细胞成熟是分批的,Ⅴ期卵巢中MA、RE卵母细胞的数量代表了即将进行的一次产卵的产卵量;卵子补充速度快,成熟卵巢每隔数天可发育成熟一批卵,一级贮备库在12─33d即更新一次,不同发育时期卵母细胞的补充是连续的。对273批 产卵进行了统计,每尾雌鱼平均4.5d产卵一次,平均批产卵量265.6粒。稀有 鲫的产卵类型为连续产卵类型。

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针对长江三峡水库蓄水后引起水库汞活化效应对生态与环境的影响问题,系统地分析了长江水系水库与河流鲤鱼肌肉的As、Cd、Cu、Fe、Hg、Mn、Pb、Se、Mn、Pb、Se、Na、Mg等元素含量的分布特征。并以丹江口水库-汉江、陈村水库-青弋江为例,用多元分析证明水库与河流的鲤鱼肌肉中As、Se、Hg、Cd等元素含量存在显著差异,同时指出水库汞活化效应引起的鱼体汞含量增加是该元素的一种生物地球化学现象,并利用同一水系水库与河流鲤鱼汞元素含量的比值R作为定量描述水库汞活化效应的指标。逐步回归分析指出,所研究的长

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主要阐述了人工湿地废水处理系统中生物学基础的研究进展。至今,对作为湿地生产者的水生植物研究较多,水生植物除直接吸收利用废水中的营养物质、吸附和富集重金属外,还起输送氧气至根区、形成根区多种微环境和维持湿地水力传输的作用;而对作为湿地分解者的微生物(包括细菌、放线菌、真菌、原生动物和藻类)的研究较少,湿地微生物的代谢活动是废水中有机物质降解的基础机制。应加强人工湿地中生物学基础、特别是湿地中微生物的结构与功能的研究,以有利于进一步探讨人工湿地净化废水的机理及改善和提高人工湿地的废水净化效果。

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连续两年对鱼腥藻的六个品系进行了大量培养比较研究,在长江中下游气候条件下,HB1042和HB1105具有稳定的生产性能,5月下旬至九月中旬123d内,平均有效生长分别为114和100d;其次是HB1058,HB686和HB1017,平均有效生长天分别为73,58和71d;HB13适应性较差。生物量生产率在5月下旬、6月中旬至9月中旬较高,除HB13外,平均都在10g干重/m~2/d以上或接近10g/m~2/d。在不同的季节它们表现出了各自的最高生物量生产率。据此,提出了逐月逐旬采取藻种搭配生产,以获得最高

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<正> 作者于1988年4—5月参加了武陵山区鱼类寄生虫的调查工作,收集到一些寄生桡足类标本,经整理,发现了一种以往文献未记载过的狭腹鳋新种,现报道如下: 模式标本保存于中国科学院水生生物研究所鱼病研究室,文中量度单位为mm。

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我国原有鱼蛭科湖蛭属两种,其中中华湖蛭广泛分布华中地区,严重危害鲤、鲫鱼。据对安徽巢湖的调查,鲤鱼的感染率较鲫鱼高,大个体的感染率又较小个体的高。此蛭每年4月上旬开始离开鱼体到湖底繁殖,12月下旬新生幼体开始侵袭鱼体。哲罗湖蛭则仅限于黑龙江流域。1964年在青岛附近的黄海以及1975年在秦皇岛附近的渤海从两种硬骨鱼体上共得到4条属同一种的大型湖蛭,经鉴定为冈湖蛭Limnotrachelobdella okae,这是该种在我国首次记载。1985年在厦门附近的南海从赤点石斑鱼鳍上得到两条同属一种的小型湖蛭,被

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<正> 水栖寡毛类在近年来受到较广泛的注意,这不仅是因为它是某些鱼类的天然饵料基础,更主要的还在于它是一类能较好地反映水体环境质量的无脊椎动物。随着我国环境保护工作的全面开展,许多单位都在努力探索水体生物监测的有效途径,这就要求了解我国常见水体中寡毛类的种类组成和数量变动等基本情况,特别是那些能够用来同当前情况相对比的“本底值”。关于我国水栖寡毛类的情况,在过去虽然陆续有所报道。但是,其中专门论述长江流域浅水湖中寡毛类的区系、生态问题的研究报告却相当稀少。本文的目的就是希望在这个方面提供有关资料,并从生物

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Except for the complement C1q, the immunological functions of other C1q family members have remained unclear. Here we describe zebrafish C1q-like, whose transcription and translation display a uniform distribution in early embryos, and are restricted to mid-hind brain and eye in later embryos. In vitro studies showed that C1q-like could inhibit the apoptosis induced by ActD and CHX in EPC cells, through repressing caspase 3/9 activities. Moreover, its physiological roles were studied by morpholino-mediated knockdown in zebrafish embryogenesis. In comparison with control embryos, the C1q-like knockdown embryos display obvious defects in the head and cramofacial development mediated through p53-induced apoptosis, which was confirmed by the in vitro transcribed C1q-like mRNA or p53 MO co-injection. TUNEL assays revealed extensive cell death, and caspase 3/9 activity measurement also revealed about two folds increase in C1q-like morphant embryos, which was inhibited by p53 MO co-injection. Real-time quantitative PCR showed the up-regulation expression of several apoptosis regulators such as p53, mdm2, p21, Box and caspase 3, and down-regulation expression of hbae1 in the C1q-like morphant embryos. Knockdown of C1q-like in zebrafish embryos decreased hemoglobin production and impaired the organization of mesencephalic vein and other brain blood vessels. Interestingly, exposure of zebrafish embryos to UV resulted in an increase in mRNA expression of C1q-like, whereas over-expression of C1q-like was not enough resist to the damage. Furthermore, C1q-like transcription was up-regulated in response to pathogen Aeromonas hydrophila, and embryo survival significantly decreased in the C1q-like morphants after exposure to the bacteria. The data suggested that C1q-like might play an antiapoptotic and protective role in inhibiting p53-dependent and caspase 3/9-mediated apoptosis during embryogenesis, especially in the brain development, and C1q-like should be a novel regulator of cell survival during zebrafish embryogenesis. (c) 2008 Elsevier Inc. All rights reserved.

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Microcystin-LR (MC-LR) is the most frequently studied cyclic heptatoxin produced by cyanobacteria, which has tremendous negative impacts on fish, while its molecular mechanism behind remained unclear at present. Here, Affymetrix Zebrafish GeneChip was used to identify alterations in gene expression of zebrafish (Danio rerio) after MC-LR exposure. Among the 14,900 transcripts in the microarray, 273 genes were differentially expressed, in which 243 genes were elevated and 30 were decreased. According to GOstat analysis, MC-LR mainly influenced the cell cycle and mitogen-activated protein kinases (MAPK) signaling pathways. In addition, many immune-related genes were also influenced. These data suggest that MC-LR could promote tumorigenesis and cause immunotoxicity in fish. (C) 2008 Elsevier B.V. All rights reserved.