水稻细菌性条斑病种子带菌检测技术研究——Ⅱ.离体检测法

经3年研究建立了一套用离体稻叶检测稻种带细条病菌的方法.应用该方法成功地将44份自然发病的细条病病种接种到离体稻叶上并产生菌脓.用1%水琼脂加90 ppm元毒苯?咪唑,在30℃下可使水稻幼苗的离体叶保持15～20 d,可满足细条病接种发病的时间需要.应用纯菌测定该方法的灵敏度,最低可检测浓度为5×10~3Cells/ml.由于选择了最佳的温度、湿度、光照、苗龄及其它有关环境条件,使1.2～4.0g的病种经研碎浸泡后浓缩针刺接种于离体稻叶上在3 d后出现病斑,5.5～8.5 d后产生菌脓.与其它血清学检测方法相比,离体检测法具有直观、可靠、简便、稳定等优点,特别可避免由于种子携带丧失活性的细条病菌或其它病菌而引起的误诊.     

APES处理的载玻片在原位杂交技术中的应用

目的：获得一种廉价的、核酸酶（RNase）处理效果好的载玻片运用于原位杂交技术中。方法：改进传统APES（3-Aminopropyl triethoxysilane）方法处理载玻片,加入载玻片高温烘烤、丙酮稀释APES等步骤,以去除RNase污染,并将处理好的载玻片分别进行冰冻和石蜡组织贴片,用原位杂交试验进行验证。结...     

五种核酸提取法对猪繁殖与呼吸综合征病毒提取效率的比较

目的：研究Trizol RNA提取法、杭州博日吸附柱RNA提取法、Promega核酸提取仪磁珠RNA提取法、西安天隆核酸提取仪磁珠RNA提取法、Thermo核酸提取仪磁珠RNA提取法等五种不同核酸提取方法对不同含量猪繁殖与呼吸综合征病毒（PRRSV）阳性样品的相对提取效率,为动物疫病监测诊断实验室核酸提取方式的选择提供技术参考。方法用五种不同核酸提取方法对4份10倍梯度稀释的PRRSV阳性血清、2份PRRSV阳性组织悬液及其离心后的上清液共8份样品同时进行核酸提取,用荧光RT-PCR方法进行检测,获取各样品PRRSV荧光RT-PCR结果的CP值,分析五种提取方式的相对提取效率。结果对合适的提取样品,磁珠提取法相对提取效率最高,吸附柱法其次,Trizol提取法相对效率较差;在三种磁珠提取法中,提取效率相差在2个CP值内,差异不明显,但以天隆磁珠提取法提取效率更高。结论预装试剂结合仪器自动化操作的磁珠法提取效果稳定,效率最高;国产仪器国产试剂提取效率不亚于进口仪器和试剂。     

温度对设施栽培甜樱桃花芽物候期的影响

利用3种温度模式管理温室栽培甜樱桃.结果表明:模式3与模式1相差较显著,模式3可以使甜樱桃花芽物候期提前,初花期早11 d,盛花期提前13 d.模式3与模式2相差不明显,初花期及盛花期分别比模式2提前3 d、4 d.揭帘时间和放帘时间对控制花芽物候期起决定作用.     

大花重瓣丁香和紫叶重瓣丁香的促成栽培试验

对大花重瓣丁香和紫叶重瓣丁香进行促成栽培试验.结果表明:摘叶法促成栽培时,紫叶重瓣丁香更适于在同一月份进行单株叶子全部摘除,其展叶期与开花期都提前,且花期也长;而不同时间全部摘叶2个品种均以8月份和9月份进行对开花特性的影响好.升温法促成栽培时,要求平均积温日数19 d,平均最高积温498℃,平均最低积温296℃.     

Dynamic viscoelastic, calorimetric and dielectric characteristics of wheat protein isolates

Dynamic oscillatory rheology of two wheat protein isolate (Prolite 100 and Prolite 200) doughs (≈48% moisture content, wet basis) were studied over a frequency range of 0.1–10 Hz during temperature sweep from 20 to 90 °C at a heating rate of 2 °C/min. Both doughs behaved similarly during heating; showed a threshold value and increased sharply, thereafter. Prolite 200 dough had a higher elastic modulus (G′) and lower phase angle (δ) whereas Prolite 100 showed a distinct gel point at 52.2 °C followed by significant increase up to 90 °C. Rheological data of doughs after isothermal heating at 90 °C for 15 min followed by cooling to 20 °C resulted in strong mechanical strength. However, Prolite 100 dough showed more viscoelastic characteristics with significant transformation from liquid-like to solid-like behavior after heating than Prolite 200. Thermal analysis of isolates indicated distinct endothermic peaks in wider temperature range (50–130 °C) at various moisture levels. Lower temperatures could be associated with denaturation of various fractions of proteins whereas higher temperature linked to glass transition temperature of isolates. SDS–PAGE did not show any clear distinction among protein subunits between two isolates. Dielectric measurements of isolates at frequencies from 500 to 3000 MHz and temperature range between 30 and 80 °C indicated Prolite 200 had higher dielectric constant (ε′) and loss factor (ε″) than Prolite 100. Isolates showed significant changes in dielectric properties above 50 °C indicating protein denaturation and supported rheological and calorimetric data.     

用磁珠富集法从AFLP片段中分离鹅微卫星DNA标记

用磁珠富集法从AFLP片段中分离微卫星DNA标记，可以避免基因组文库的构建和筛选这一繁重的工作，既节省时间又节约费用。利用少量的内切酶组合建立一系列AFLP DNA，然后用生物素标记的简单重复序列（SSR）作探针与其杂交，杂交复合物固定到包被有链亲和素的磁珠上，经过一系列洗涤过程，含有SSR的AFLP片段被吸附到磁珠表面。这些片段经洗脱下来后，先用对应的AFLP引物扩增，再进行克隆和测序，根据SSR两端的保守序列设计引物，经过多态性分析后，便可得到微卫星DNA标记。用这种方法已成功地从6个中国地方品种鹅中分离到30个微卫星DNA标记。其中有11个引物表现为多态性好，特异性强且相互之间并不连锁。各品种平均多态信息含量（PIC）在0．513～0．546之间。说明这11个微卫星均为高度多态，可作为有效的遗传标记用于鹅品种间遗传多样性和系统发生关系的分析，并为建立鹅遗传图谱、重要经济性状的基因定位及标记辅助选择奠定基础。     

Glass transition temperature of starches with different amylose/amylopectin ratios

The glass transition temperatures (T_g) of starch with different amylose/amylopectin ratios were systematically studied by a high-speed DSC. The cornstarches with different amylose contents (waxy 0; maize 23, G50 50 and G80 80) were used as model materials. The high heating speed (up to 300 °C/min) allows the weak T_g of starch to be visible and the true T_g was calculated by applying linear regression to the results from different heating rates. It is confirmed for the first time, that the higher the amylose content is, the higher the T_g is for the same kind of starch. The sequence of true T_g of cornstarch is G80 > G50 > maize > waxy when samples contain the same moisture content, which corresponds to their amylose/amylopectin ratio. It was found that T_g was increased from about 52 to 60 °C with increasing amylose content from 0 to 80 for the samples containing about 13% moisture. The microstructure and phase transition were used to explain this phenomenon, in particular the multiphase transitions that occur in high-amylose starches at higher temperatures, and the gel-ball structure of gelatinized amylopectin.     

机械通风条件下玻璃温室热环境数值模拟

利用CFD方法对机械通风条件下温室内热环境进行建模,在模型中考虑了作物、太阳辐射和热辐射,采用标准k-ε湍流模型和SIMPLE算法的有限体积法对流场微分方程进行离散,对室内流场和温度变化以及分布进行了数值模拟.通过在Venlo型温室采集关键位置的温度和速度数据,与仿真结果比较发现测试点的温度误差除少数外均控制在3 ℃之内,相对误差控制在10%之内,验证了建立CFD模型的有效性.     

芒果玻璃化转变与状态图研究

研究了25℃下芒果的吸附等温线,实验数据采用GAB模型进行非线性拟合,结果表明芒果的吸附等温线呈J型,其单分子层干基含水率为0.107 g/g。芒果的状态图由冻结曲线、玻璃化转变温度曲线和最大冻结浓缩状态组成,其中冻结温度和玻璃化转变温度由差示扫描量热仪(DSC)测量得到。冻结温度和玻璃化转变温度的实验数据,分别采用Clausius-Clapeyron方程和Gordon-Taylor方程进行非线性拟合。实验结果显示,最大冻结浓缩状态时的固形物湿基质量分数为84%,在此状态下的玻璃化转变温度为-52.9℃。状态图的建立能够预测芒果贮藏过程的稳定性,并且能够提供最适干燥或冷冻加工条件。