谈对半成品抗原半数感染量判定方法的理解

在兽用生物制品生产中,常用病毒半数感染量（EID50）来表示病毒类疫苗及其半成品抗原的效价,作者以鸡新城疫活疫苗为例,对其半成品抗原及成品EID50的判定方法进行比较分析,加深了对准确表达每毫升半成品抗原病毒含量判定方法的理解。     

Genome-wide detection of signatures of selection in three Valdostana cattle populations

The Valdostana is a local dual purpose cattle breed developed in Italy. Three populations are recognized within this breed, based on coat colour, production level, morphology and temperament: Valdostana Red Pied (VPR), Valdostana Black Pied (VPN) and Valdostana Chestnut (VCA). Here, we investigated putative genomic regions under selection among these three populations using the Bovine 50K SNP array by combining three different statistical methods based either on allele frequencies (F_ST) or extended haplotype homozygosity (iHS and Rsb). In total, 8, 5 and 8 chromosomes harbouring 13, 13 and 16 genomic regions potentially under selection were identified by at least two approaches in VPR, VPN and VCA, respectively. Most of these candidate regions were population-specific but we found one common genomic region spanning 2.38 Mb on BTA06 which either overlaps or is located close to runs of homozygosity islands detected in the three populations. This region included inter alia two well-known genes: KDR, a well-established coat colour gene, and CLOCK, which plays a central role in positive regulation of inflammatory response and in the regulation of the mammalian circadian rhythm. The other candidate regions identified harboured genes associated mainly with milk and meat traits as well as genes involved in immune response/inflammation or associated with behavioural traits. This last category of genes was mainly identified in VCA, which is selected for fighting ability. Overall, our results provide, for the first time, a glimpse into regions of the genome targeted by selection in Valdostana cattle. Finally, this study illustrates the relevance of using multiple complementary approaches to identify genomic regions putatively under selection in livestock.     

赭曲霉毒素的毒理学试验

用含2.569mg/kg赭曲霉毒素A (Ochratoxin A.以下称OA)的饲料,对40日龄左右的星波罗肉用鸡进行了饲喂试验试验鸡表现为精神沉郁,食欲不振、肠炎、贫血、极度消瘦等症状,于喂后13～18天,先后衰竭死亡,剖检发现肾、肝和肠道等都有明显的病理变化。经用高效液相色谱仪(HPLC)测定,肾脏,肝脏内OA的残留量分别为0.179mg/kg和0.1302mg kg。用从饲料中提纯的OA对孵化5日龄的鸡胚进行了气室内接种。根据接毒后记录的鸡胚死亡数和死亡率。计算出半数致死量为0.128μg。     

应用Logistic方程确定花椒枝条低温半致死温度

以一年生休眠枝条为材料,对3个品种的花椒进行了电解质外渗率测定,应用Logistic方程建立回归模型;确定半致死温度在-20.20～17.07℃之间,并且抗寒性顺序从小到大依次为油椒、秦安一号、大红袍;相关系数介于0.9541～0.9902之间,表明不同低温和低温持续时间的电解质外渗率遵循Logistic方程的变化规律,且与半致死温度呈线性关系。     

Autumn growth and cold hardening of winter wheat under simulated climate change

Abstract

Plant responses to elevated CO₂ are governed by temperature, and at low temperatures the beneficial effects of CO₂ may be lost. To document the responses of winter cereals grown under cold conditions at northern latitudes, autumn growth of winter wheat exposed to ambient and elevated levels of temperature (+2.5°C), CO₂ (+150 µmol mol^?1), and shade (?30%) was studied in open-top chambers under low light and at low temperatures. Throughout the experiment, temperature dominated plant responses, while the effects of CO₂ were marginal, except for a positive effect on root biomass. Increased temperature resulted in increased leaf area, total biomass, total root biomass, total stem biomass, and number of tillers, but also a lower content of total sugars and a weaker tolerance to frost. The loss of frost tolerance was related to the larger size of plants grown at elevated temperature. The 30% light reduction under shading did not affect the growth, sugar content, or frost tolerance of winter wheat. At the low temperatures found at high latitudes during autumn, the atmospheric CO₂ increase is unlikely to enhance autumn growth of winter wheat to any significant extent, while a temperature increase may have important and major effects on its development and growth.     

GX-50对中波紫外线辐射皮肤成纤维细胞的保护作用

为观察花椒中的提取物GX-50是否对UVB诱导的光老化皮肤细胞具保护作用,使用组织块法分离培养原代人皮肤成纤维细胞,通过观察不同剂量UVB照射后的细胞形态学改变确定后续实验的UVB单次照射剂量;MTT法检测不同浓度GX-50处理后的细胞活性;采用衰老相关β-半乳糖苷酶(SA-β-Gal)细胞化学染色法确定皮肤细胞衰老程度;测定丙二醛(MDA)和ROS含量评估皮肤细胞氧化损伤的程度;酶联免疫吸附试验(ELISA)检测细胞TGF-β1表达量的变化;Western blot法检测细胞胶原蛋白表达量的变化。结果显示UVB辐射成纤维细胞后,细胞胞体增大、颗粒增多、部分细胞死亡,在不引起细胞明显死亡的UVB最大剂量50 mJ/cm2作用下,10-6mol/L的GX-50在孵育24h时可显著增加成纤维细胞存活率(125.7%,P0.01);经UVB照射后细胞SA-β-Gal染色阳性率增加,GX-50预处理后辐射组的阳性率明显降低(45.9%,P0.05);UVB组与对照组相比,MDA、ROS含量明显上升,GX-50预处理后辐射组MDA、ROS含量分别下降了22.6%(P0.01),22.8%(P0.05),基本与对照组持平;UVB辐射后TGF-β1分泌减少,GX-50预处理后辐射组则明显上升(14.7%,P0.05);Western blot结果显示,UVB可显著抑制胶原蛋白的表达,而GX-50预处理后表达量则基本恢复。推断GX-50对UVB引起的皮肤成纤维细胞损伤起到了保护作用,其机制可能是清除自由基和抗氧化,同时活化被UVB抑制的TGF-β信号通路,从而增加了胶原蛋白的表达。     

应用SPSS软件进行农药试验数据的统计分析

SPSS软件是国际著名的统计分析软件,具有方便、可靠、功能丰富的特点。应用SPSS进行数据分析可以不必说明算法,其统计结果被国际同行广泛认可。本文介绍了应用SPSS软件对农药数据进行统计分析的方法,包括:t检验、方差分析以及致死中量的计算。     

蜡蚧轮枝菌对月季长管蚜的毒力测定

研究结果表明蜡蚧轮枝菌对月季长管蚜有较强的致病性,孢子浓度2.0×105个/mL时可造成大量月季长管蚜感染死亡,其LT50=（6.62±0.14）d; 而高浓度2.0×108个/mL对月季长管蚜感染致死的LT50=（4.69±0.16）d,第8天的死亡率达93.6%,致死中时随浓度增加而缩短。第5天的致死中浓度为（1.72±0.18）×107个/mL,第8天为（1.53±0.15）×104个/mL,致死中浓度随时间增加而减小。     

西芹黄萎病防治药剂筛选和毒力测定

本文针对西芹黄萎病病原菌开展室内防治药剂筛选和药剂毒力测定。按照药剂最大推荐剂量从14种供试药剂中初筛出8种有效药剂,以进口多菌灵、菌哥、新世生、瓜果类太宝、太医最佳,对菌丝生长的抑制率达100%。8种药剂对病原菌菌丝生长的EC50依次为进口多菌灵（0.0063 mg/ml）＜太医（0.0073 mg/ml）＜活根菌灭（0.0077 mg/ml）＜枯萎灵（0.0079 mg/ml）＜瓜果类太保（0.0092 mg/ml）＜根腐宁（0.0103 mg/ml）＜新世生(0.0192 mg/ml) ＜菌哥（0.0844mg/ml）,进口多菌灵和活根菌灭对病原菌孢子萌发的EC50分别为1.50×10-4 mg/ml和1.55×10-4 mg/ml。     

几种植物乙醇提取物对螺旋粉虱的生物活性

采用玻管药膜法和田间试验研究飞机草、青葙、假蒟等6种植物叶片的乙醇提取物对螺旋粉虱的生物活性.结果表明,各供试提取物均对螺旋粉虱表现出一定的生物活性,其中以飞机草和青葙的活性最高,其LC50分别为753.40,999.81 mg/kg,其余4种提取物对螺旋粉虱的活性大小依次为:假茼>菠萝蜜>含羞草>桃金娘.田间试验结果表明,飞机草和青葙提取物对螺旋粉虱成虫均具有较高活性,在50倍浓度处理下,飞机草和青葙提取物的防效均在75%以上.