A comparison between multivariate Slash, Student's t and probit threshold models for analysis of clinical mastitis in first lactation cows

Robust threshold models with multivariate Student's t or multivariate Slash link functions were employed to infer genetic parameters of clinical mastitis at different stages of lactation, with each cow defining a cluster of records. The robust fits were compared with that from a multivariate probit model via a pseudo‐Bayes factor and an analysis of residuals. Clinical mastitis records on 36 178 first‐lactation Norwegian Red cows from 5286 herds, daughters of 245 sires, were analysed. The opportunity for infection interval, going from 30 days pre‐calving to 300 days postpartum, was divided into four periods: (i) ?30 to 0 days pre‐calving; (ii) 1–30 days; (iii) 31–120 days; and (iv) 121–300 days of lactation. Within each period, absence or presence of clinical mastitis was scored as 0 or 1 respectively. Markov chain Monte Carlo methods were used to draw samples from posterior distributions of interest. Pseudo‐Bayes factors strongly favoured the multivariate Slash and Student's t models over the probit model. The posterior mean of the degrees of freedom parameter for the Slash model was 2.2, indicating heavy tails of the liability distribution. The posterior mean of the degrees of freedom for the Student's t model was 8.5, also pointing away from a normal liability for clinical mastitis. A residual was the observed phenotype (0 or 1) minus the posterior mean of the probability of mastitis. The Slash and Student's t models tended to have smaller residuals than the probit model in cows that contracted mastitis. Heritability of liability to clinical mastitis was 0.13–0.14 before calving, and ranged from 0.05 to 0.08 after calving in the robust models. Genetic correlations were between 0.50 and 0.73, suggesting that clinical mastitis resistance is not the same trait across periods, corroborating earlier findings with probit models.     

Influence of ovariectomy and estrogen replacement on gene expression profile of myocardium in rats

AIM:To investigate the influence of ovariectomy and estrogen replacement treatment on profile of gene expression in myocardium by cDNA microarray,and to characterize the targeting genes of estrogen.METHODS:cDNA microarray containing 1 400 rat cDNAs was used to study the genes differentially expressed in myocardium between sham (Ⅰ),ovariectomy (Ⅱ,OVX) and estrogen replacement treatment (Ⅲ,OVX+E2) group.Then down-regulated genes in myocardium of OVX rats were further confirmed by RT-PCR.RESULTS:177 genes were differentially expressed in myocardium between sham and OVX rats,with 91 genes up-regulated and 86 genes down-regulated in OVX rats.164 genes were differentially expressed in myocardium between OVX and OVX+E2 rats,with 113 genes up-regulated and 54 genes down-regulated in OVX rats.There were 54 genes differentially expressed in OVX compared to sham and OVX+E2.They are involved in membrane channels and transporters (18),cell receptors (9),intracellular transducers/effectors/modulator (7) and metabolism (6).Most of the genes (45) were down-regulated in OVX rats and up-regulated in OVX+E2 rats.RT-PCR test confirmed the results of cDNA microarray.CONCLUSIONS:Long-term estrogen replacement may influence the expression of genes involved in membrane channels and transporters,cell receptors,intracellular transducers/effectors/ modulator and metabolism.Long-term estrogen replacement has some beneficial effects on ionic concentration and cardiac function which partially comes from the results of influence of expression on Na+,K+-ATPase and Na+/H+ exchanger.Estrogen has an inhibitory effect on the expression of dopamine receptor,which partially clarify the myocardial protection of estrogen.     

苯醚甲环唑·丙环唑乳油气相色谱分析

本文介绍了采用气相色谱法用HP-5毛细管柱,以邻苯二甲酸二正辛酯为内标物,氢火焰离子化检测器对苯醚甲环唑.丙环唑乳油进行定量分析。结果表明,苯醚甲环唑、丙环唑的线性相关系数为1.000 0、0.999 9;平均回收率为99.87%、99.98%;标准偏差为0.12、0.04;变异系数为0.82%、0.28%。     

1%蛇床子素水乳剂的高效液相色谱分析

采用反相高效液相色谱法对蛇床子素进行分离定量,本方法的标准偏差为0．004, 变异系数0．41％;平均回收率为99．86％;线性相关系数为0．999 99。     

10%吡嘧磺隆可湿性粉剂的液相色谱分析

本文所述应用液相色谱法测定吡嘧磺隆可湿性粉剂有效成分含量的测定方法,此方法采用甲醇、水和冰乙酸为流动相,使用C18柱、紫外检测器的高效液相色谱,经验证其添加回收率为100.09%,标准偏差为0.133,变异系数为1.33%,线性方程相关系数为0.9997。本试验方法操作简便,分离效果好,响应时间短,是理想的分析方法。     

刺桐姬小蜂在中国的适生区分析

运用CLIMEX的气候相似系数法,对入侵害虫刺桐姬小蜂在中国的适生区进行了分析和预测,结果表明:中国大陆有18个省区45个市、县(地区)适合该虫生存,大体分布于18.14°N～36.00°N,98.30°E～121.36°E范围内,这些地区也是刺桐属植物的主要分布区。     

苜蓿黄萎病菌在我国的适生性分析研究

本文以适生性评判指标分析为基础,采用生物学建模与GIS分析相结合的方法,依据我国677个气象站点的逐月气温数据以及全国土壤pH等值线图,对苜蓿黄萎病菌在我国的适生性作了分析研究。结果表明,苜蓿黄萎病菌在我国的适生性强,适生范围较广,每年4~9月份,该病菌在我国西北、东北以及华北地区的适生程度处于较高水平。鉴于此,我国应加强苜蓿黄萎病菌的植物检疫措施力度,严防该病的传入或扩散。     

杨梅酸性转化酶基因cDNA分离及表达分析

杨梅果实富含蔗糖,酸性转化酶是蔗糖代谢关键酶,根据植物酸性转化酶基因保守区序列设计引物,提取杨梅叶片RNA,逆转录获得cDNA,以此为模板通过PCR技术扩增到长度为516bp的基因片段,克隆入pMD18-T载体中,命名为MrIVR1(GenBank:DQ339699)。测序及同源性检索表明,该基因推导氨基酸序列与君子兰、葡萄、草莓、胡萝卜等酸性转化酶基因氨基酸序列同源性为60%～69%。运用ClustalX软件对植物转化酶基因进行了系统树分析,结果显示,MrIVR1编码的蛋白质属于细胞壁酸性转化酶。半定量RT-PCR表达分析显示,MrIVR1基因在杨梅果实发育早期表达量最高,随着果实的发育表达量下降,在成熟果实中表达水平较低。     

15份葡萄种质亲缘关系的ISSR分析

利用ISSR标记对15份葡萄材料进行了基因组多态性分析,从60条引物中筛选出15条用于葡萄的ISSR扩增。共扩增出105条带,其中多态性条带91条,多态性百分率为86.7%。根据ISSR扩增结果,利用NTSYSpc2.10e软件进行Jaccard相似性系数分析,15份葡萄材料的遗传相似系数为0.27～0.75,平均遗传相似系数为0.471。通过UPGMA进行聚类分析,探索亲缘关系。在遗传相似系数0.39处,15份葡萄材料可分为2大类群。第1类包含7份山葡萄资源、2个山欧杂交品种,第2类包含3个欧亚种品种、2个欧美杂种品种和1个美洲杂种品种。由此可见,山葡萄与欧亚种、美洲杂种葡萄的亲缘关系较远,欧亚种与美洲杂种之间亲缘关系较近。