Development of novel pesticides based on phytoalexins: Part 2. Quantitative structure-activity relationships of 2-heteroaryl-4-chromanone derivatives

Phytoalexins are low-molecular-weight chemicals that immune systems of plants produce and accumulate in response to infections, especially those of fungal origin. Although their content is not high in plants, yet they have shown unique fungicidal activity and played an important role in the defence system of plants. In searching for novel environmentally benign fungicides with high activity, the structures of flavanone derivatives, one of the most important phytoalexins groups, have been modified via bioisosteric substitution and a series of 2-heteroaryl-4-chromanones were designed and synthesized. They showed good fungicidal activities against rice blast disease, Pyricularia grisea (Sacc). Their IC50 values were tested in vitro and the relationship between structure and fungicidal activity was analyzed quantitatively using a Hansch-Fujita approach. The results showed that hydrophobicity was very important for fungicidal activity and there is apparently an optimum hydrophobic property for the molecules at a log Pow value of about 2.7. In addition, the results indicated that electronic effects played an important role in binding with the receptor and that the C=O group was probably a electron-accepting site. The quantitative structure-retention correlative equation of the title compounds was also established.     

Molecular Variability of the Capsid Protein of the Prune Dwarf Virus

Sequences of the capsid protein gene and the preceding intergenic region of eleven isolates of prune dwarf virus from central Europe were determined. The isolates were obtained from plum, cherry and peach trees. Comparison of all sequenced isolates (including two sequences published previously) revealed high (88%) conservation of the capsid protein gene. The highest degree of identity was observed in the C-terminal half, where only 13 amino acid substitutions could be observed in contrast to the N-terminal half with 22 substitutions. No reasonable correlation between amino acid substitutions and host species and/or geographic origin of the isolates was observed. Alignment with capsid protein genes of other ilarviruses revealed apple mosaic virus, elm mottle virus, lilac ring mottle virus and prunus necrotic ringspot virus as the most related to prune dwarf virus. Unlike the isolates of related prunus necrotic ringspot virus all the isolates of prune dwarf virus shared extensive conservation of the intergenic region. Portions of RNA3 were selected for design of universal primers for PCR detection.     

鹿流行性出血病毒分子生物学研究进展

鹿流行性出血病毒是一种在全世界野生及驯养的有蹄动物中广泛存在的重要病原体.该病毒属呼肠病毒科环状病毒属,有12个血清型,是一种有10个节段(L1-L3、M4-M6、S7-S10)的双链RNA病毒,编码10个蛋白(VP1-7和NS1、NS2、NS3/NS3A).VP7蛋白具有很强的抗原性且保守性最高.VP2与病毒型特异性有关,可诱导产生中和抗体.VP3为群特异性抗原,高度保守,具有亲水性保守区域.非结构蛋白NS1、NS2和NS3/NS3A及其编码序列均相当保守.该病毒的分子生物学诊断技术主要有PCR和核酸探针杂交技术.     

DNA分子标记与动物遗传育种

DNA分子标记技术的出现,对动物遗传育种产生了深远的影响,利用DNA标记可以研究动物整个基因组水平的遗传变异,进行动物遗传资源研究、标记辅助选择、标记辅助导入、杂种优势预测、选配、品种与品系确认、构建高分辨率遗传连锁图谱、QTL搜寻定位等。目前在动物遗传中广泛使用的标记主要有mtDNA、RFLP、RAPD、AFLP、SSR、SNP和EST标记。本文综述了这些标记技术的原理、特点,并根据其特点,分析其在动物遗传育种中的应用,并通过维普数据库搜索比较分析研究者对各种技术的使用情况。     

猪传染性胃肠炎病毒分子生物学研究进展

猪传染性胃肠炎病毒(TGEV)基因组为不分段的单股正链RNA,其编码4种结构蛋白和3种非结构蛋白。TGEV S蛋白是基因工程研究的重点,近年来,S蛋白在大肠埃希菌、沙门菌、腺病毒等中得到了高效表达。将传染性胃肠炎病毒的基因组人工改造成为感染性cDNA的表达载体,此载体可在ORF3处插入外源基因,异源基因绿荧光蛋白可稳定、高效地表达。TGEV基因1和其他冠状病毒相比保守性很强,所以对TGEV聚合酶的研究,特别是其中保守酶的研究,对于抗TGEV及其他冠状病毒药物的研究有着重要的意义。     

PEF辅助快速提取非特异性奶牛脾脏转移因子的实验研究

应用PEF成功从奶牛脾脏中提取非特异性转移因子，并与常规提取法和复合酶提取法进行了比较.经理化特性分析，奶牛脾脏转移因子是以低分子多肽（〈10kD）为主的混合物，含有少量核酸和氨基酸.实验表明，将物料溶解于6倍质量的磷酸盐（pH7．0）缓；中液中，在脉冲电场强度为25kV／cm，脉冲数为16μs，和流速为2mL／min的条件下，提取液中低分子多肽的含量有最大值9．85mg／mL.PEF提取率是常规方法的2倍，复合酶法的1．47倍.PEF法耗时短，操作简单，成本低，因此，PEF提取是一种很有希望的提取非特异性奶牛脾脏转移因子方法.     

Prediction of response to marker-assisted and genomic selection using selection index theory

Selection index methods can be used for deterministic assessment of the potential benefit of including marker information in genetic improvement programmes using marker-assisted selection (MAS). By specifying estimates of breeding values derived from marker information (M-EBV) as a correlated trait with heritability equal to 1, it was demonstrated that marker information can be incorporated in standard software for selection index predictions of response and rates of inbreeding, which requires specifying phenotypic traits and their genetic parameters. Path coefficient methods were used to derive genetic and phenotypic correlations between M-EBV and the phenotypic data. Methods were extended to multi-trait selection and to the case when M-EBV are based on high-density marker genotype data, as in genomic selection. Methods were applied to several example scenarios, which confirmed previous results that MAS substantially increases response to selection but also demonstrated that MAS can result in substantial reductions in the rates of inbreeding. Although further validation by stochastic simulation is required, the developed methodology provides an easy means of deterministically evaluating the potential benefits of MAS and to optimize selection strategies with availability of marker data.     

免疫佐剂的作用机制及其应用

从抗原微粒化佐剂（如不溶性铝盐胶体、免疫刺激复合物、脂质体）、缓慢释放抗原佐剂（如油乳佐剂、抗原的微型包囊）、微生物佐剂（如细菌毒素、短小棒状杆菌菌苗、分枝杆菌及其成分、肽聚糖）、分子佐剂（如细胞因子、C3d分子、共刺激分子、超抗原、热休克蛋白、CpG序列）和其他佐剂（如维生素E、硒、抗生素类、拟胸腺素药物、蜂胶、中药多糖）等几方面阐述了免疫佐剂的性质、作用机制及应用的研究现状，为免疫佐剂的临床应用和进一步研制提供了参考资料。     

草原红牛肉用性状微卫星标记研究

本研究选用草原红牛、草原红牛与利木赞牛杂交后代共计42头作为试验牛群体，以体尺、体重作为衡量其生长发育指标，进行肉牛肌肉度线性评分，并屠宰测定其肉用性能，利用SPSS软件分析了3个微卫星位点基因标记与生长性状、屠宰肉用、肌肉度线性评分性状的关系。结果表明，IDVGA46等位基因D（211bp）对3个肌肉度评分性状肩部、腰厚、大腿肌有负相关；等位基因B（205bp）在腰厚方面有正相关。等位基因F（249bp）对牛的胸深、坐骨端高等生长性状有正相关。BM1824等位基因C（211bp）对腿围性状、净肉率和净肉重性状均有正相关。IDVGA2等位基因C（209bp）对牛的肉用性能有负相关。