RAPD技术对地方鸡种群体遗传结构的分析

利用ＲＡＰＤ技术对４个地方鸡种和１个引进鸡种的群体遗传结构进行分析，通过筛选的５个随机引物ＯＰＨ－０２、ＯＰＨ－０５、ＯＰＨ－１３、ＯＰＨ－１６、ＯＰＧ－０７对５个鸡种的池ＤＮＡ进行多态性研究，结果表明：５个引物共产生条带６１个，扩增产物片段的长度一般从１５０ｂｐ－４ｋｂ。     

基于SSR标记的苜蓿种质资源遗传多样性与群体结构分析

种质资源遗传多样性和群体结构的分析是进行复杂性状关联分析的前提条件.从140对SSR引物中筛选到16对多态性引物,对82份苜蓿(Medicago spp.)材料进行遗传多样性与群体结构分析.结果表明;16对SSR引物共检测出190个等位变异,平均11.88个;多态性比率66.67％～100％,平均为83.05％;基因多样性为0.1447～0.3637,平均为0.2577;PIC为0.0079～0.9432,平均为0.5501.群体结构分析表明,当K=5时△K最大,即82份苜蓿材料可划分为5个类群,其中75.61％的种质遗传组分相对比较单一,24.39％的种质遗传背景比较复杂.苜蓿种质资源遗传多样性丰富,群体结构的划分与种质的来源不完全相关.     

Canine leukocyte adhesion deficiency: presence of the Cys36Ser beta-2 integrin mutation in an affected US Irish Setter cross-breed dog and in US Irish Red and White Setters

Canine leukocyte adhesion deficiency (CLAD) is a primary immunodeficiency disease characterized by recurrent bacterial infections in the presence of marked leukocytosis. The disease was 1st described in the mid-1980s in a cross-breed Irish Setter Dog in the United States. It results from a defective beta-2 subunit of heterodimeric leukocyte adhesion proteins. The causative mutation for CLAD in Irish Setter Dogs from Europe has been identified as a missense mutation at base pair position 107 in the beta-2 integrin subunit gene (ITGB2) that results in an amino acid change from cysteine to serine at amino acid 36 (Cys36Ser) in the beta-2 integrin subunit protein. In the current work, the originally described dog with CLAD has been genetically tested and shown to have the same mutation as the European Irish Setters. This suggests that the mutation has been in the Irish Setter population for many generations spanning more than 2 decades. A related breed, the Irish Red and White Setter, has a history of interbreeding with Irish Setters and shares a common ancestry with the Irish Setter breed. DNA from Irish Red and White Setters residing in the United States was screened either by sequencing or by the newly developed restriction enzyme test for the Irish Setter Cys36Ser CLAD mutation. Seven of 54 dogs tested (13%) were found to be carriers of the Irish Setter CLAD mutation. Five of these were directly related to a sire from the UK, demonstrating the importation of an allele from another continent and establishing the need for genetic testing in this breed in the United States.     

Monitoring and identification of residues of anabolic preparations in slaughtered cattle by HPLC with diode array detection

Summary

The new combination of isocratic high performance liquid chromatography (HPLC) with on line UV spectrum detection via a diode array configuration has been applied to the detection and identification of anabolics present in application sites of cattle.

Combination of the characteristic retention time in the HPLC chromatogram and a comparison of the full spectrum between 190–400 nm of the anabolic components with that of a standard resulted in a very reliable identification. By means of this method 117 samples of application sites were investigated for the presence of anabolic residues. Of the xenobiotic anabolics, 19‐nortestosterone (NT) was found most frequently (in 96 cases), whereas diethylstilbestrol (DES) was found in only 11 cases.

In all samples the identification of NT and DES was confirmed by high resolution gas chromatography‐mass spectrometry (GCMS).     

GMOs in animal agriculture: time to consider both costs and benefits in regulatory evaluations

In 2012, genetically engineered (GE) crops were grown by 17.3 million farmers on over 170 million hectares. Over 70% of harvested GE biomass is fed to food producing animals, making them the major consumers of GE crops for the past 15 plus years. Prior to commercialization, GE crops go through an extensive regulatory evaluation. Over one hundred regulatory submissions have shown compositional equivalence, and comparable levels of safety, between GE crops and their conventional counterparts. One component of regulatory compliance is whole GE food/feed animal feeding studies. Both regulatory studies and independent peer-reviewed studies have shown that GE crops can be safely used in animal feed, and rDNA fragments have never been detected in products (e.g. milk, meat, eggs) derived from animals that consumed GE feed. Despite the fact that the scientific weight of evidence from these hundreds of studies have not revealed unique risks associated with GE feed, some groups are calling for more animal feeding studies, including long-term rodent studies and studies in target livestock species for the approval of GE crops. It is an opportune time to review the results of such studies as have been done to date to evaluate the value of the additional information obtained. Requiring long-term and target animal feeding studies would sharply increase regulatory compliance costs and prolong the regulatory process associated with the commercialization of GE crops. Such costs may impede the development of feed crops with enhanced nutritional characteristics and durability, particularly in the local varieties in small and poor developing countries. More generally it is time for regulatory evaluations to more explicitly consider both the reasonable and unique risks and benefits associated with the use of both GE plants and animals in agricultural systems, and weigh them against those associated with existing systems, and those of regulatory inaction. This would represent a shift away from a GE evaluation process that currently focuses only on risk assessment and identifying ever diminishing marginal hazards, to a regulatory approach that more objectively evaluates and communicates the likely impact of approving a new GE plant or animal on agricultural production systems.     

扁蓿豆遗传多样性研究初探

论述了扁蓿豆遗传多样性研究的依据,利用不同生境条件下生长的野生和栽培品种,采用形态标记、细胞标记、生化标记和分子标记的方法多方面地对扁蓿豆进行遗传多样性的研究。     

中药免疫抑制剂的研究现状及临床应用

目前临床上常用的免疫抑制药物如激素、环磷酰胺、环孢菌素等的毒副作用较大,且不能从根本上控制疾病的发生和发展，而中药免疫抑制剂应用免疫耐受机理,具有毒副作用小、疗效好等特点,故广泛应用于临床。作者对近年来有关中药免疫抑制作用的基础研究及临床作用作一综述，就其研究过程中存在的不足及发展趋势提出自己的见解，为今后中药免疫抑制剂的研究开发提供参考。     

苜蓿育种几个问题的探讨

在对主要苜蓿遗传资源与遗传特性进行陈述的同时, 重点对苜蓿遗传特性与育种进程的关系、目前常见的育种方法以及苜蓿育种的发展现状进行了阐述,并就近年来我国在苜蓿育种领域内存在的主要问题进行了分析,旨在为今后的苜蓿育种工作提供参考依据。     

养殖环境生物除氮脱氮技术研究进展

随着我国水产养殖业的快速发展,养殖环境中氮的污染问题日益严重。生物除氮脱氮技术由于具有无可比拟的优势而受到人们的重视,近年来无论在基础理论还是应用实践方面发展迅速。本文总结了水产养殖中该项技术的最新研究进展,并指出今后的研究方向和重点。     

基于混合遗传算法的谐波齿轮传动优化设计

以谐波齿轮传动体积最小为优化设计目标,建立了混合离散变量优化设计数学模型。引入混沌移民算子,对基本遗传算法进行了改进,以维持群体的多样性,提高全局收敛能力。提出了一种设计变量的离散化处理方法,结合染色体编码的修正技术,在遗传算法中染色体按离散化后的设计变量进行离散搜索。开发了混合离散变量优化的改进遗传算法程序,给出了谐波齿轮传动的混合离散变量优化设计实例,所得优化设计参数符合设计规范,不需进一步处理就可直接用于制造。