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Search Results: 1 - 10 of 1786 matches for " Chinese Academy of Agricultural Sciences "
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Marginal diversity and its application to Chinese sheep breeds conservation

Yuehui Ma Institute of Animal Science,Chinese Academy of Agricultural Sciences,Beijing,

生物多样性 , 2005,
Abstract: This paper introduced an approach of marginal diversity, and evaluated the contribution, marginal diversity and conservation potency of each of the 11 sheep breeds from northern China based on genetic distance and extinction probability. The results showed that the marginal diversity of Sunite sheep was the highest (-0.2008), Tan sheep (-0.1932) and Lanzhou large tailed sheep (-0.1843) the next, and Minxian black fur sheep the lowest (-0.1268). The conservation potency of Lanzhou barge tailed sheep was the highest (0.1419), the second was Tong sheep (0.1017), and small tailed Han sheep was the lowest (0.0365). Our result suggested that the optimum conservation strategy is to give priority to those breeds with the highest conservation potency,rather than to the most endangered breeds; thus, Lanzhou large tailed sheep and Tong sheep should be given conservation priority.
The importance of classical biological control to biodiversity protection

Lu Qingguang Biological Control Institute,Chinese Academy of Agricultural Sciences,Beijing,

生物多样性 , 1997,
Abstract: Exotic pests under certain conditions are able to threaten a native biodiversity, breaking down the ecological balance and bringing great economic losses. The science of classical biological control (or the Classical Biocontrology) has been demonstrated that the sustainable pest control can be obtained by the introduction of natural enemies from the pest home region into its invaded region. This is one of the strategy and tactics on biodiversity protection, it is: from biodiversity to biodiversity. A general situation on classical biocontrol in China, including summary of the research history, current studies and discussions are presented in this paper.
Recent Advances in Structures and Relative Enzyme Properties of Xylanase

YANG Hao Meng,YAO Bin,FAN Yun Liu Feed Research Institute,Chinese Academy of Agricultural Sciences,Beijing,China Biotechnology Research Center,Chinese Academy of Agricultural Sciences,Beijing,China,

生物工程学报 , 2005,
Abstract: Xylanase can hydrolyze xylans into xylooligosaccharides and D xylose, and has great prospect for applications in feed industry, paper and pulp industry, food industry and environment science. The study of xylanase had been started in 1960's.With the development and application of the new technologies, such as molecular biology, structural biology and protein engineering, many progresses have been made in the research of structures and functions of xylanase. This paper reviews the research progress and trend in the structure correlating with the important properties of xylanase. Analyses of three dimensional structures and properties of mutants have revealed that glutamine and aspartic acid residues are involved in the catalytic mechanism.The thermostability of xylanase correlated with many factors, such as disulfide bridges,salt bridges,aromatic interactions,cotent of arginine and proline,and some multidomain xylanase have thermostability domains in N or C terminal.But no single mechanism is responsible for the remarkable stability of xylanase.The isoelectic points and reaction pH of xylanase are influenced by hydrophobicity and content of electric charges.Many researches had demonstrated that aromatic amino acid,histidine,and tryptophan play an important role in improving enzyme substrate affinity.The researches of structures and functions of xylanase are of great significance in understanding the catalytic mechanism and directing the improvement of xylanase properties to meet the application requirement.
Effect of global warming on insect:a literature review

CHEN Yu,MA Chunsen Institute of Environment,Sustainable Development in Agriculture,Chinese Academy of Agricultural Sciences,

生态学报 , 2010,
Abstract: Climate change is an important environmental problem which has caused great concern around the world. Climate change\|particularly global warming\|has a direct and indirect impact on poikilothermic animals, especially for insects and the biotic community around them. We review the most recent progress in effects of global warming on insects and methodologies used in the research. Global warming may lead to an advance in insect phenology, and shift in geographic distribution to higher latitude and altitude. It may also restrain abundance of the low temperature adaptive species and promote abundance of the high temperature adaptive species. In addition, global warming disturbs the synchrony of host plant\|herbivore\|natural enemy in phenology and other interactions among different species, modifies the spectrum of host\|plants and feeding capacity of insects. An intense stress caused by long\|term high temperature leads to a variation of gene frequency in insect population. Furthermore, global warming in terms of the increase in daily average temperature and maximum temperature, and the decrease in diurnal temperature have crucial effects on the development, reproduction, and survival of insect. The main research approaches to study effects of global warming on insects include: direct observation in field, regression models developed with historical data, day\|degree models, and ecological risk assessment programs e.g. CLIMEX and GIS, paleontological comparison, ecological experiments in climate chambers, and examination of the gene frequency with gene marker. At last, we review the weakness of previous studies and point out research directions in the near future: (1) investigating biology and ecology of more species of important crop pests, and inter\|specific interactions under global warming scenarios; (2) studying more on insect adaptation to high temperature; (3) developing new experimental approaches and collecting better data under artificial climate conditions; (4) constructing validated ecological models of insects which was driven by temperature and other ecological factors.
Composition and diversity of Arthopod community in Masson Pine stands

HAN Bao-Yu,Anhui Agricultural University,Hefei Institute of Zoology,Chinese Academy of Sciences,Beijing,

生物多样性 , 2001,
Abstract: 在不采取任何营林和治虫措施的皖南九连山林场马尾松纯林中设林分相似的2块样地,面积均为22m×22m。1997年1月~1998年12月,每月1次垂直分层对两样地节肢动物群落的调查表明每样地植食性、捕食性、寄生性昆虫和蜘蛛类群的物种数占该样地总物种数的百分比分别约52%、14%、8%和20%;每样地的益害物种数之比都约为11.2;益害个体数之比是15.7和16.6;相同林间层次的优势目昆虫或优势种蜘蛛相同;每样地的物种数量都是以灌木草本层最多,依次为乔木层、枯枝落叶层和土壤层。两样地乔木层、灌木草本层、土壤层和枯枝落叶层的节肢动物平均个体数百分率分别为39.6%、33.1%、22.8%和4.6%。3~8月物种数和多样性指数较大,5、8月为物种数高峰期。主成分分析显示群落的稳定性较差。
Diversity of Chinese yellow cattle breeds and their conservation

CHEN You Chun,CAO Hong He Institute of Animal Science,Chinese Academy of Agricultural Sciences,Beijing,

生物多样性 , 2001,
Abstract: Based on a summary of cattle breeds originating in China according to data from skull classification, coat color, blood protein polymorphisms, body stature, ecological characters, chromosome group, mtDNA, and archaeological discoveries, Chinese cattle are from two major origins. One was Bos tuarus , including turino mongolian in the regions outside of the Great Wall and draft taurine on the Qinghai Tibet plateau. The other origin was Zebu cattle, of which there were three. The first was from west Asia, the Africander type, second was an indicus origin, influencing Yunnan humped cattle, and the third was South east Asian in origin, which was supposedly the result of crosses between Bibos banteng and local high hump cattle. Humpless cattle are mainly the Mongolian breed and their derived breeds, and Tibetan draft cattle. The humped cattle in central regions of China, the Nanyang breed, is obviously influenced by the Africander type. When this form breeds with others, the resulting forms have a well developed chest dewlap and folds. Humped cattle breeds in south east China have chest dewlaps with poorly developed fold and without an abdominal dewlap. In general, they are two ecological systems, which are divided into three groups. On the ecological side, there are humpless, low humped and high humped cattle. In geographic distribution there are the Mongolian group, Huanghe and Huaihai group and Changjiang and Zhujiang group. Nowadays, more than 30 breeds have been introduced from abroad, and this is accelerating the loss of local cattle genotypes. We make some proposals for conservation of cattle genetic resources.
Study on the toxicity of acid rain to microbiota in soils
Liao Ruizhang,Cao Hongfa,Liu Liangui,Gao JinlanInstitue of Soils,Fertilizers,Chinese academy of Agricultural Sciences,Beijing,ChinaInstitue of Ecology,Chinese Academy of Environmental Sciences,Beijing,China,
Liao Ruizhang
,Cao Hongf,Liu Liangui,Gao Jinlan

环境科学学报(英文版) , 1991,
Abstract: With simulated acid rain and acidification, the soils from both Nanning and Liuzhou municipalities, Guangxi Zhuang Nationality Autonomous Region have been studied to determine the counts of azotobacter, bacteria, actinomyces and the activity of urease in soils, and the changes in respiratory intensity of soil so as to identify the toxicity of acidic substances to microbiota and enzyme in such soils. The concept of the critical pH of toxicity has been developed and used to discuss the representation of the concept, the basis on which the soil treated with simulated acid rain can be taken as an object of study, and the criteria for the identification of toxicity. Based on that as mentioned above, it was found that acid rain behaved to have toxicity to the microbiota in soils from Liuzhou other than from Nanning. The findings may be regarded as an objective basis to study the toxicity of acidic substances to microbiota and enzyme in soils in this region.
Elements and achievements in research on domestic animal biodiversity

CHEN You Chun,MA Yue Hui,WANG Duan Yun Institute of Animal Husbandry,Chinese Academy of Agricultural Sciences,Beijing,

生物多样性 , 2003,
Abstract: For years the research on domestic animal diversity has emphasized diversity of economic traits, ecological diversity and diversity of breeds. Recently, research on genetic diversity of domestic animals has developed rapidly. Research on clusters of breeds, systematic conservation, the relationships between genetic diversity and economic traits, and ecological diversity has all made great progress, including some success with QTL, and creating transgenic and cloned animals. The genetic analysis between domestic breeds and their wild relatives was applied to breeding new strains or breeds by hybridization.Evaluation methods using biotechnology have confirmed that many local breeds are unique to China,and this has given rise to worldwide interest.
Cloning and expression of ophc2,a new organphosphorus hydrolase gene
Cloning and expression of ophc2, a new organphosphorus hydrolase gene

WU Ningfeng,DENG Minjie,LIANG Guoyi,CHU Xiaoyu,YAO Bin & FAN Yunliu Biotechnology Research Institute,Chinese Academy of Agricultural Sciences,Beijing,China,

科学通报(英文版) , 2004,
Abstract: The amino acid sequences of N-terminal and internal peptide of OPHC2,purified from Pseudomonas pseudoalcaligenes strain C2-1 in our lab,are determined.The full-length organphosphorus hydrolase gene ophc2 is cloned by PCR using the degenerate primers designed according to the sequences and future inverse PCR.The ophc2 gene is 975 bp long with G+C content of 63%,comprising one open reading frame encoding a polypeptide of 324 amino acids with a molecular weight of 36 kD.The nucleotide sequence of ophc2 shows low homolo- gies with those organphosphorus hydrolase genes deposited in Gen- Bank,one of which exhibits the highest homology of 46.4% with ophc2.The organphosphorus hydrolase protein expressed in E.coli bears normal bioactivity.
An analysis of interspecific associations of Pinus squamata with other dominant woody species in community succession

ZHANG Zhi-Yong,TAO De-Ding,LI De-Zhu Kunming Institute of Botany,Chinese Academy of Sciences,Kunming Agricultural College,Jiangxi Agricultural University,Nanchang,

生物多样性 , 2003,
Abstract: 通过方差分析、χ2检验和共同出现百分率PC等的计算,对五针白皮松(Pinus squamata)分布的群落中主要树种间的种间联结性进行了定量分析。研究结果表明:2个五针白皮松分布的群落总体种间关联性为显著正相关,其中半阳坡上的群落为正相关,阴坡上的群落为显著正相关。由于半阳坡上的群落为针阔叶混交林,而阴坡上的群落为常绿阔叶林,表明五针白皮松分布的群落有从针阔叶混交林向常绿阔叶林演替的趋势。χ2检验和共同出现百分率PC的结果说明,阴坡群落的树种间有较密切的正相关,五针白皮松与其他树种总体上无关联性,表明五针白皮松是一个阳性先锋树种,它与其他物种的共同出现往往是由于随机的因素。同时,通过五针白皮松年龄结构并联系云南松(Pinus yunnanensis)与其他物种关系的分析得出结论,五针白皮松的濒危状况可能是在长期的植被演化过程中被阔叶树种排挤所造成的。
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