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101.
用逆转录多聚酶链式反应从凡纳对虾中检出传染性皮下组织和造血器官坏死病毒 总被引:11,自引:1,他引:11
传染性皮下组织和造血器官坏死病毒 (IHHNV) ,是一种细小病毒 ,它能感染所有起源于中胚层和外胚层的对虾组织细胞[1] 。在许多养殖对虾的国家都有IHHNV ,特别是中美洲国家和地区[2 ] 的对虾养殖业深受其害。随着各国间对虾贸易的急剧增长 ,IHHNV地理分布范围日益广泛 ,迄今为止 ,已扩散到中国台湾、新加坡、马来西亚、泰国、印度尼西亚、澳大利亚、菲律宾、厄瓜多尔、秘鲁等国家和地区[2 -4] 。红额角对虾 (Penaeusstylirostris)、斑节对虾 (P .monodon)、短沟对虾 (P .semisulcatu… 相似文献
102.
Leucorrhinia caudalis is a rare dragonfly, threatened throughout its European distribution. The species was formerly widespread in the Swiss lowlands, but only a single population remained in the 1980s. However, a spread has recently been observed, with additional ponds being colonised, sometimes at considerable distance. Despite this evidence of recent long-distance dispersal, it is unknown whether L. caudalis regularly moves among ponds or whether this is a rather rare event. A combination of an ecological mark-resight and a population genetic study was applied to investigate contemporary dispersal and the genetic footprint of the recent population history of L. caudalis in Switzerland. DNA for genetic microsatellite analysis was extracted from exuviae. The mark-resight study and the genetic analysis gave congruent results. They showed that L. caudalis is mostly a sedentary species, with only a few contemporary dispersal events over distances up to 5 km being observed. The genetic analysis was in agreement with the recent population history of the Swiss populations. The oldest and largest population showed large genetic diversity and acted as source population for the recent spread of L. caudalis in Switzerland. Recurrent gene flow among this source population and close populations caused substantial local genetic variation in the latter, as well as low population differentiation. The two recently founded distant populations (?30 km distance) were genetically less diverse and highly differentiated. These distant populations and another recently colonised population also expressed signatures of genetic bottlenecks. 相似文献
103.
设计了一款在0~100℃和反向电压VR为0~1 000 V条件下,能够测试二极管反向漏电流特性的测试仪.它采用桥式输入I、CL7650组成的高精度放大电路、ADC0804和AT89S51完成了高压到低压的转换、信号的放大、采样、量化及显示,通过编程软件对测试结果进行修正,提高系统的测量精确度.对二极管IN4007的测试结果表明:所得反向漏电流分辨率达0.1 nA,准确度达1.79%. 相似文献
104.
105.
mRNA差异显示技术是近年来国外发展起来的攻克隆新基因的一种新方法,同时已广泛用于人类基因调控和克隆研究。本文论述了这一新技术的原理、发展现状和在动物遗传育种中的应用领域。 相似文献
106.
岩羊血液生化遗传多态性的研究 总被引:3,自引:0,他引:3
采用聚丙烯酰胺凝胶电泳和火焰光度法对青海省19只岩羊13个血液生化遗传基因座的多态性特征进行了研究。结果发现:①ES2、ES3、ES4、S-LDH、S-ALP和TF6个基因座存在多态性,而KE、HB、AMY1、AMY2、AMY3、ES1、RBC-LDH和RBC-ALP7个基因座呈单态;②被检岩羊的多态性基因座比例为46.2%,表明岩羊的血液生化遗传基因座有颇大的遗传变异性。 相似文献
107.
LIANG Kang-jing LIN Wen-xiong WANG Xue-ren CHEN Zhi-xiong GUO Yu-chun LIANG Yi-yuan CHEN Fang-Yu LI Ya-juan 《中国农业科学(英文版)》2002,1(8):837-844
Following NC Ⅱ design, the developmental genetic behavior of tiller number (TN) in three-line indica hybrid rice was studied using additive-dominance developmental genetic models and the corresponding statistical methods. The results showed that dominance effects were predominant for TN. The expression of those additive effects were affected by environment and genotype interaction, but the expression of dominance effects were not affected. Heterosis was the strongest in the middle developmental periods of TN. Additive effects and dominance effects were selectively expressed throughout in the entire tillering developmental stage.Analysis of genetic correlation between TN at different stages and the productive panicles indicated that a close correlation appeared earlier in the populations with higher heterosis than in those with less heterosis. Utilization of heterosis at the middle tillering stage might enhance the final biomass but reduce the percentage of productive panicles. 相似文献
108.
Rabies is an enzootic viral disease widespread throughout the world. Although it is a vaccine-preventable disease, the annual number of human deaths caused by rabies is estimated to be 32,000 in Asia. Phylogenetic analysis based on sequence data of the partial N gene of rabies viruses in Asia has shown that the viruses are divided into five genogroups, distributed in Middle East, South Asia, South East Asia, Malay, and Arctic regions. The genetic relationships among these rabies viruses agree basically with the results of previous studies. Meanwhile, new types of vaccines are being developed by applying gene manipulation techniques to rabies virus in order to overcome the disadvantages of current vaccines. This article reviews the molecular epidemiology of rabies in Asia and progress made in the development of new-generation rabies vaccines with the goal of elimination or control of rabies in Asia. 相似文献
109.
The results of this study indicated a great deal of genetic variation in a number of characters of horticultural interest
in kiwifruit seedling populations, and therefore, a potential to improve kiwifruit by vine selection. High narrow sense heritability
was shown for pedicel length(0.62) and flowering duration (0.50) in male vines, and pedicel length (0.67),floral shoot percentage
(0.54), leaf length-width ratio (0.64), fruit elongation (0.64) and fruit weight (0.52) in female vines. For these traits,
selection of superior seedlings should lead to rapid genetic improvement in these populations.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
110.
Olga E. Scholten Ritsert C. Jansen L. C. Paul Keizer Theo S. M. De Bock Wouter Lange 《Euphytica》1996,91(3):331-339
Summary Inheritance of resistance to beet necrotic yellow vein virus (BNYVV) was studied in segregating F2 and backcross families obtained from crosses between resistant plants of the sugar beet selection Holly-1-4 or the wild beet accession Beta vulgaris subsp. maritima WB42 and susceptible parents. Greenhouse tests were carried out, in which seedlings were grown in a mixture of sand and infested soil. Virus concentrations of BNYVV in the rootlets were estimated by ELISA. To discriminate resistant and susceptible plants, mixtures of normal distributions were fitted to log10 virus concentrations, estimated for segregating F1, F2 and BC populations of both accessions. The hypothesis that Holly-1-4 contained one single dominant major gene was accepted. For WB42, results fitted with the hypotheses that resistance was based on either one (or more) dominant major gene(s) showing distorted segregation, or two complementary dominant genes, which are both required for resistance. Resistance from WB42 appeared to be more effective against BNYVV than resistance from Holly-1-4.This research was carried out as part of a PhD study at the Graduate School Experimental Plant Sciences (EPS), Department of Virology, Wageningen, The Netherlands 相似文献