德南牛全基因组变异解析和功能基因挖掘

[目的]研究德南牛的群体遗传结构和解析影响其重要性状的关键基因。[方法]通过主成分分析、群体进化树分析、群体遗传结构分析等方法,研究德南牛的遗传结构和与其他品种的亲缘关系;同时,利用全基因组SNP数据,计算德南牛与德国黄牛、南阳牛群体固定指数(Fst)和核苷酸多样性比值(π ratio)、复合似然比(CLR)、XP-EHH等多种选择信号指标,以筛选出德南牛基因组上受到选择的信号,鉴定出重要的候选基因。[结果] 德南牛具有欧洲普通牛(0.789)、东亚牛(0.176)、中国瘤牛(0.035)的混合血统。在θπ和CLR方法中鉴定出93个共有基因,使用FST和XP-EHH方法鉴定出17个共有基因。进行富集以及基因功能注释后,发现这些基因可能与生殖性能(TUBB3、NSD2、GRM1、ERBB4)、生长性状(RFX3、FGFR3、GABRB1、PDE4D)、环境适应性(PGR、GRIA4)和免疫系统反应(P2RY12、P2RY13、GPR87、P2RY14、GPR171)有关。[结论]本项研究发现德南牛血统受德国黄牛影响较多,且挖掘了德南牛基因组内可能具有经济意义的性状相关的选择特征,为德南牛种群的选育提高提供理论支撑。     

甘南州林区的大型药用真菌

本文报道了在甘南林区的大型药用真菌１６５种。并对其重要种类进行列述,提出了合理开发利用的措施和建议。     

甜菜夜蛾性信息素组分的鉴定及其田间试验

采用气相色谱仪(GC)及气质联用仪(GC-MS)等技术对我国甜菜夜蛾性信息素组分的鉴定结果表明,雌蛾性信息素腺体中含有4种组分,分别为Z9,E12-14:Ac(A)、Z9-14:OH(B)、Z9-14:Ac(C)和Z9,E12-14:OH(D);田间和室内种群各组分的比例(A:B:C:D)分别为47:18:18:17和43:18:23:16,比例及滴度在两种群间未有显著差异;雄蛾田间引诱测定表明,组分A、B显示性信息素活性。几种不同配比的硅橡胶塞诱芯在田间均显示极高的诱蛾活性,以9:1的AB二元诱芯(剂量100μg)最高,其诱蛾量与黑光灯相当,两者呈显著的正相关性,表明该诱芯可替代黑光灯用于甜菜夜蛾的种群测报。利用性诱捕器进行田间种群监测显示,1999年浙江省慈溪市的甜菜夜蛾共发生6代,以第4、5代发生量最高。     

4种药剂对豇豆根结线虫病的防治效果

为了更好地防治豇豆根结线虫病,对4种杀线虫剂进行了田间防效评价试验。结果表明,供试的4种药剂均对豇豆根结线虫有一定的防效,能控制土壤中２龄幼虫的数量和抑制根结的形成,其中10％噻唑膦颗粒剂对豇豆根结线虫的防效最好,具有低残留、持效期长等优点,可作为防治豇豆根结线虫的首选药剂; 其次为５％阿维菌素颗粒剂。同时供试的4种药剂在试验剂量范围内均对豇豆安全,建议在生产上推广应用10％噻唑膦颗粒剂和５％阿维菌素颗粒剂来防治豇豆根结线虫病。     

从动物源性食品安全存在的问题谈可追溯制度的建立与完善

食品安全,尤其是作为食品的重要组成部分的动物源性食品安全,直接关系着广大人民群众的身体健康和生命安全,关系着国民经济与社会     

The 16MΔvjbR as an ideal live attenuated vaccine candidate for differentiation between Brucella vaccination and infection

Brucellosis brings great economic burdens for developing countries. Live attenuated vaccines are the most efficient means for prevention and control of animal Brucellosis. However, the difficulties of differentiating of infection from vaccine immunization, which is essential for eradication programs, limit their applications. Therefore, the development of a vaccine that could differentiate infection from immunization will overcome the limitations and get extensive application. VjbR is a quorum sensing regulator involving in Brucella's intracellular survival. The vjbR∷Tn5 mutants have been proven effective against wild type strain challenge, implying its possibility of use in vaccine candidate development. To further evaluate this candidate gene, in the present study, the antigenicity of purified recombinant VjbR protein was analyzed. Antibodies to Brucella melitensis VjbR could be detected in sera from patients and animals with brucellosis but not in control ones, implying the potential use of this protein as a diagnostic antigen. Then a vjbR mutant of B. melitensis 16M was constructed by replacing the vjbR with kanamycin gene. The mutant showed reduced survival in macrophage and mice. Vaccination of BALB/c mice with 16MΔvjbR conferred significant protective immunity against B. melitensis strain 16M challenges, being equivalent to which induced by the license vaccine Rev.1. The vjbR deletion mutant elicited an anti-Brucella-specific immunoglobulin G response and induced the secretion of gamma interferon and interleukin-10. The most importance is that, the use of vjbR mutants as vaccines in association with diagnostic tests based on the VjbR antigen would allow the serological differentiation between infected and vaccinated animals. These results suggest that 16MΔvjbR is an ideal live attenuated vaccine candidate against B. melitensis and deserves further evaluation for vaccine development.     

Influence of prolonged arable cropping on lignin compounds in sandy soils of the South African Highveld

The preservation of plant residues is important for sustainable arable cropping. Lignin is a marker for plant residues in soils. We have investigated influences of the length of cultivation on the dynamics of lignin. Composite samples were taken from the top 20 cm of soils that have been cropped for periods varying from 0 to 98 years in each of three different agro‐ecosystems in the Free State Province of South Africa. Lignin‐derived phenols were determined in the <2 µm (clay), 2–20 µm (silt), 20–250 µm (fine sand) and 250– 2000 µm (coarse sand) size separates. With increasing length of cultivation, the concentration of such phenols decreased to 36% of that in the grassland. The lignin contents as proportions of the total carbon did not change during cultivation, suggesting that there was no selective enrichment of lignin moieties as C was lost as a result of cultivation. The loss rate constants of lignin concentrations in particle‐size fractions increased in the order clay (0.17 year^?1) ≤ silt (0.18 year^?1) < fine sand (0.20 year^?1) < coarse sand (0.22 year^?1). Increasing ratios of phenolic acids to aldehydes in bulk soil, silt and fine sand fractions with increasing length of cultivation indicated that side chains were being oxidized. The ratios in the silt fraction, however, decreased after 10–20 years. We attribute this to a loss of lignin together with silt by wind erosion, resulting in a rejuvenation of lignin compounds in the remaining silt‐sized pools of C.     

Numerical analysis of injection molding for the Syringe Barrel with optimum design and processing condition

The numerical analysis was performed to predict the potential problem, often occurring during the manufacturing process of the disposable medical device of a great volume. The cavity filling analyses were performed for the new design of the 3cc Syringe Barrel using polypropylene(PP1), and a new nucleated polypropylene(PP2) material for better clarity. These analyses have been performed for different processing conditions as well as various wall thickness designs for both materials. With the nucleated material, only the original wall thickness design has been studied at two different processing conditions for comparison purpose. This study was conducted to investigate the optimum part design and processing condition for two different materials. The most desirable design was selected with Design 3 for material utilization and reduced flow stresses by comparing the field results. The new nucleated polypropylene provided slightly better product quality and processing.     

西花蓟马抗药性研究进展

西花蓟马是世界范围内蔬菜和花卉上的重要害虫之一,使用化学药剂是防治西花蓟马的主要手段,目前西花蓟马已对有机氯、有机磷、氨基甲酸酯、拟除虫菊酯、阿维菌素和多杀菌素等多种杀虫剂产生了抗药性。本文从抗药性现状、抗性机制和抗性治理等几个方面介绍了国内外有关西花蓟马抗药性的研究进展。