38 resultados para Plutella xylostella (Linnaeus 1758)
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<正> 一、绪言关于中国淡水鱼类的研究,如果从C.Linnaeus的记载算起,至今已超过一个半世纪了。在这个时期内,特别是前100年,全部工作几乎只限于种类的筒单描述。进行这些工作的鱼类学者,大抵都是外国人,他们绝大多数没有到过中国,一般仅凭从中国采得的少数标本,予以鉴定研究。个别早期作者,甚至往往只根据一幅鱼的绘图,就进行描述鉴定,创立新种。到二十世纪三十年代,才有我国学者从事本国鱼类的研究,开始比较系统的在全国一些主要河流进行鱼类调查。到四十年代止,可以说除边远地区外,我国的主要经济鱼类资源基本上都有
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While it has been widely suggested that freshwater fishes from East Asia invaded the western Palaearctic, details about this process are largely unknown. Here, using the cytochrome b gene, we evaluated the phylogenetic relationships of a small group of Eurasian primary freshwater fishes (Cobitidae), which are widely distributed and species rich in East Asia and Europe, with the purpose of inferring their invasion process of Europe from East Asia. Though phylogenetic relationships of cobitids were not well resolved, our analysis could identify three sister groups formed by the European and East Asian cobitids, which brought new insights into the biogeography of the genera Cobitis, Misgurnus, and Sabanejewia. The present results support the view that Asian cobitid fishes may have invaded Europe at least five times independently, and once reverse colonization of European cobitids to East Asia could also be found. Ancestral Sabanejewia might have been the first cobitids to cross Siberia and invade the EMZS (Euro-Mediterranean zoogeographic subregion) about 33.54 million years ago (MYA). One lineage of Cobitis and the ancestor of Misgurnus fossilis (Linnaeus) almost in the same time invaded the Europe, responding to 16.71 MYA and 16.59 MYA, respectively. Three different lineages of Cobitis were found to have invaded the EMZS from East Asia, and once reverse invasion to East Asia occurred to one subclade of European Cobitis. And our data also suggest that the diversity of East Asian cobitid fishes, especially of the genus Cobitis, is greatly underestimated.
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A rhabdovirus associated with a lethal hemorrhagic disease in cultured turbot Scophthalm us maximus Linnaeus was isolated. The virus induced typical cytopathogenic effects (CPE) in 9 of 15 fish cell lines examined and was then propagated and isolated from infected carp leucocyte cells (CLC). Electron microscopy observations revealed that the negatively stained virions had a typical bullet-shaped morphology with one rounded end and one flat base end. The bullet-shaped morphology was more obvious and clear in ultrathin sections of infected cells. Experimental infections also indicated that the S. maximus rhabdovirus (SMRV) was not only a viral pathogen for cultured turbot, but also had the ability to infect other fish species, such as freshwater grass carp. A partial nucleotide sequence of the SMRV polymerase gene was determined by RT-PCR using 2 pairs of degenerate primers designed according to the conserved sequences of rhabdovirus polymerase genes. Homology analysis, amino acid sequence alignment, and phylogenetic relationship analysis of the partial SMRV polymerase sequence indicated that SMRV was genetically distinct from other rhabdoviruses. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the purified SMRV revealed 5 major structural proteins, and their molecular masses were estimated to be about 250, 58, 47, 42, and 28 kDa. Significant serological reactivity differences were also observed between SMRV and its nearest neighbor, spring viremia of carp virus (SVCV). The data suggest that SMRV is likely a novel fish rhabdovirus, although it is closely related to rhabdoviruses in the genus Vesiculovirus.
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The largest damming project to date, the Three Gorges Dam has been built along the Yangtze River (China), the most species-rich river in the Palearctic region. Among 162 species of fish inhabiting the main channel of the upper Yangtze, 44 are endemic and are therefore under serious threat of global extinction from the dam. Accordingly, it is urgently necessary to develop strategies to minimize the impacts of the drastic environmental changes associated with the dam. We sought to identify potential reserves for the endemic species among the 17 tributaries in the upper Yangtze, based on presence/absence data for the 44 endemic species. Potential reserves for the endemic species were identified by characterizing the distribution patterns of endemic species with an adaptive learning algorithm called a "self-organizing map" (SOM). Using this method, we also predicted occurrence probabilities of species in potential reserves based on the distribution patterns of communities. Considering both SOM model results and actual knowledge of the biology of the considered species, our results suggested that 24 species may survive in the tributaries, 14 have an uncertain future, and 6 have a high probability of becoming extinct after dam filling.
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提出了一种自动检测C语言程序中是否含有死循环的方法.该方法基于程序分析技术,包括循环展开和路径可行性分析技术.该方法首先通过遍历控制流图生成待查循环的检验路径;之后通过分析检验路径的可行性以及路径之间的联系,判断这些路径是否符合死循环模式.在此方法基础上实现了原型工具LoopAnalyzer,并对一组基准程序进行测试.实验结果表明此工具能有效地检测出C语言程序中的死循环,并且准确率较高.
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对中国(大陆)的海洋深地震探测工作进行了回顾,重点讨论了南海北部边缘OBS探测的几条剖面及动力学意
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由于采样条件和培养条件的限制,深海微生物研究的较少,因此目前海洋微生物资源的研究主要集中在近海和浅海。而深海独特的生态环境,使微生物形成了独特的代谢体系,成为新颖化合物的重要来源,具有很好的开发应用前景。本文首次较为系统的研究了深度为1758-3600m南海海底沉积物中深海微生物资源的分离和活性菌株的筛选情况,旨在为探索我国南海深海微生物资源提供一定的科学依据。 采用多种分离培养基从6个不同深度(1758、2620、3200、3500、3587和3600m)的南海深海沉积物样品中,分离到225株深海微生物,包括40株放线菌和185株细菌。以分离得到的225株深海微生物为研究对象,从产蛋白酶、抗真菌、杀虫三个方面进行活性菌株的筛选,研究南海深海沉积物中的微生物资源状况: (1).将分离到的225株深海微生物,同时在10℃、28℃、45℃三个温度下进行产低温蛋白酶、中温蛋白酶、高温蛋白酶的筛选。初筛结果表明:这225株深海微生物大都有大小不同的产蛋白酶能力。10℃有产蛋白酶的有109株,28 ℃产蛋白酶的有160株,45℃产蛋白酶的有117株。筛选到一株在45℃下有较强产蛋白酶能力的菌株B1394,其酶活可达873U/ml,有一定的应用前景。通过形态观察、生理生化测定、16SrDNA序列测定,将B1394定名为枯草芽孢杆菌(Bacillus subtilis)。其粗酶液性质研究发现:最适酶活温度60℃,最适pH 8.0, 40℃、50℃和60℃热稳定性较好, Mn2+ 、Mg2+ 、Ca2+对该蛋白酶有激活作用,Hg2+ 、Fe3+ 、Cu2+ 、Zn2+ 、 Fe2+对其有抑制作用,苯甲基磺酰氟(PMSF)几乎完全抑制其活性,推断为丝氨酸蛋白酶。 (2).对其中100株深海细菌和40株深海放线菌,以立枯丝核菌( Rhizoctonia solani)和白色念珠菌(Candida albicans)为靶菌进行了抗真菌活性的筛选。初筛结果表明:分别有37株和35株深海细菌对立枯丝核菌和白色念珠菌有抑菌活性,分别占被检测细菌数目的37%和35%;有18株深海放线菌对立枯丝核菌有抑制作用,占被检测放线菌总数的45%。筛选到一株有较强抗真菌活性的深海放线菌SHA6,其发酵液对包括尖孢镰刀菌(Fusarium oxysporum)在内的10种植物病原菌有明显的抑制作用。对其发酵液的理化性质进行初步研究发现SHA6发酵液具有良好的热稳定性和酸碱稳定性, 对SHA6进行分子生物学鉴定后将其初步定名为为橙色单胞菌(Aurantimonas altamirensis)。 (3).以卤虫为初步筛选模型,对其中的20株深海放线菌进行了杀虫方面的筛选,结果发现有5个深海放线菌菌株表现有较强的杀虫活性。其中深海放线菌SHA4发酵液的乙酸乙脂提取物杀卤虫的活性最强,在浓度为100μg/ml时杀卤虫活性为83%,而在浓度400ppm时,48h可以杀死38%的甜菜夜娥。对SHA4进行分子生物学鉴定后将其初步定为拟诺卡氏菌属(Nocardiopsis sp)。 总之,本论文阐明了我国南海深海沉积物中微生物资源状况的初步研究结果,为进一步开发利用我国南海深海微生物资源奠定了基础。
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对2006年春季南京地区一次“泥雨”形式的湿降尘特征进行了系统分析,并在此基础上对泥雨粉尘来源及泥雨降尘形成机制进行了探讨.
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在研究汾河景区垂柳柳厚壁叶蜂生物学特征的基础上,通过对柳厚壁叶蜂种群数量的调查,分析了该虫在羽化产卵阶段与垂柳生长期的耦合过程、新老树种虫害程度的差异及其与环境的关系.结果表明:柳厚壁叶蜂对垂柳最大危害的枝条是从第1叶片到第6叶片的生长期;柳厚壁叶蜂种群在草地覆盖条件下密度较大.最后对汾河景区防治柳厚壁叶蜂的危害,提出了生态防治对策.
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报道山西省的淡水红藻植物,共计有15种,隶属于6目,7科,9属,即紫球藻Porphyridiumpurpureum Bory DrewetRoss,暗紫红毛菜Bangiaatropurpurea Roth Agardh,细弱弯枝藻CompsopogontenellusLingetXie,弯枝藻C.coeruleus BalbisexC.Agardh Montagne,灌木状拟弯枝藻Copsopogonopsisfruticosa Jao Seto,异孢奥杜藻AudouinellaheterosporaXieetLing,硬枝奥杜藻A.chalybea Roth Bory,矮小奥杜藻A.pygmaea Kützing Weber-vanBosse,棘刺红索藻Thoreahispida Thore Desvaux,鸭形串珠藻Batrachospermumanat-inumSirodot,胶串珠藻B.gelatinosum Linnaeus DeCandolle,弧形串珠藻B.arcuatumKylin,绞扭串珠藻B.in-tortumJao,细连珠藻Sirodotiatenuissima Collins SkujaexFlint和胭脂藻Hildenbrandiarivularis Leibmann Agardh.
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采用活体注射秋水仙碱制备鱼类肾细胞染色体、PHA肌肉注射制备肾细胞染色体和鱼类早期胚胎制备染色体等多种方法。以空气干燥法制片Giemsa染色,对鲻鱼Mugil cephalus Linnaeus、真鲷Pagrosomus major(Temminck et Schlegel)、黑鲷Sparus macrocephalus(Basilewsky)、黑鮶Sebastes schlegeli (Hilgendorf)、石鲽Kareius bicoloratus (Basilewsky)、牙鲆Paralichthys olivaceus (Temminck et Schlegel)等分属四目、五科的六种海产鱼的染色体组型进行了考察和分析。研究结果表明:1、一般活体注射秋水仙碱制备海产鱼肾细胞染色体方法的有丝分裂指数虽然略低于PHA制备肾细胞染色体方法的有丝分裂指数。但它是最快最简便且很有效的方法,利用鱼类早期胚胎制备海产鱼染色体标本的方法也很有效,但要受到生物季节的限制。2、通过对六种海产鱼染色体组型分析得到,鲻鱼为48条端部着丝点染色体;真鲷的二倍体2n=48,有1对亚端部着丝点染色体。其余全部为端部着丝点染色体;黑鲷的二倍体2n=48。有3对中部着丝点染色体。2对亚中部着丝点染色体,其余全部为端部着丝点染色体。黑鮶的二倍体2n=48,有1对中部着丝点染色体,其余全部为端部着丝点染色体,石鲽的二倍体2n=48。全部为端部着丝点染色体;牙鲆的二倍体2n=48,全部为端部着丝点染色体。本文还对鱼类染色体的多态现象以及染色与进化的关系进行了讨论。
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近年来,在“清洁生产”、“生态养殖”以及“生物修复”理论的指导下,在贝类稚贝培育和成贝养殖过程中实施贝藻混合模式,已经成为国内外学者研究的热点之一。本文在封闭水体中进行了龙须菜(Gracilaria lemaneiformis Weber-van Bosse)和文蛤(Meretrix meretrix Linnaeus)稚贝以及成贝的混养实验,初步探索了混养系统中的互利机制,监测了水体中理化因子和生物因子的变化规律,测定了养殖生物的生长情况及营养成分,构建了混养系统中贝藻混养的合理模式。并且采用新技术-T-RFLP监测了养殖水体中细菌的动态变化。主要研究成果如下: 1. 在龙须菜与稚贝混养实验中,平均水温为17.5±3.2℃。研究结果表明较低的温度抑制了龙须菜的生长,总平均日生长率最高为0.81%/d,小于与成贝混养实验的最高特定生长率1.79%/d。养殖水体中氨氮和磷酸盐是最主要的无机污染物,而龙须菜对养殖水体营养盐的去除作用显著, 35天后混养系统中养殖水体的氨氮和磷酸盐平均浓度较单养系统低43.37μmol/L、1.23μmol/L,分别相差95.06%、94.85%。 2. 在龙须菜与成贝混养实验中,平均水温为23.1±2.3℃,适合龙须菜的生长,结果表明龙须菜对氨氮和亚硝氮的吸收高达86%~98%,对无机磷的吸收可达99%,养殖生物的生长情况良好,养殖生物体内的营养成分要好于单养系统中的养殖生物。对于氨基酸总含量,加入龙须菜的养殖系统中文蛤体内的氨基酸总含量要比单养系统中文蛤体内氨基酸总含量高26.0mg/g,高出后者5.01%。引入龙须菜在一定程度上可以抑制异养细菌和致病性弧菌的生长,相对抑制率达到77.75%。在本实验中,尽管龙须菜可以抑制异养细菌的生长,但如果引入过多会导致嗜江蓠细菌过度增加,可能反而会破坏原有的微生态平衡。 3. 采用T-RFLP技术对养殖水体中的总细菌群落进行了分析,摸索出合理的方法和步骤,通过聚类分析将养殖水体中细菌群落分为两个群落,并且认为在养殖水体中,微生物群落的变化是及其复杂的,第六周时两个群落变化不一致。并且相对来说,龙须菜的引入可能会对某些群落造成抑制,但也可能会对其它细菌群落起到促进作用。 4. 稚贝和成贝分别与龙须菜的混养实验结果表明,在养殖系统中引入龙须菜可以改善养殖环境,龙须菜和文蛤的适宜混合比例为1:1能取得较好的生态效应。