真核细胞蛋白酶体降解血红蛋白分子机理

从真核细胞蛋白酶体分子结构及血红蛋白分子结构出发,阐述真核细胞蛋白酶体降解血红蛋白的分子机理,以探索出调控降解血红蛋白的有效途径,为畜禽血液的综合利用提供理论依据。     

通过小麦Ms2近等基因系的抑制缩减杂交分析揭示小穗和花药中差异表达基因

以Ms2近等基因系处于减数分裂期的可育小穗cDNA作为驱动因子(driver),以同一时期的不育小穗cDNA作为测验因子(tester)进行缩减杂交(SSH),将扩增后的缩减杂交产物进行克隆,构建了一个包含882个重组克隆的SSH文库.分别以可育小穗和不育小穗的cDNA为探针与SSH文库克隆进行反式Northern杂交,结果显示接近90%的克隆在不育小穗中呈上调表达.对文库中21个克隆插入片段的序列相似性分析表明其中有18个与来源于穗部或减数分裂期的花药cDNA同源.13个克隆的编码产物与已知功能的蛋白质同源,其中5个参与碳代谢活动,4个参与胞内分子的运输,2个蛋白产物参与染色体的构成及染色体的结构变化,1个是生长素抑制蛋白,1个是转录因子.用中国春缺体四体材料对9个克隆进行了染色体定位,其中一个克隆定位于第四染色体同源群,与Ms2所在的染色体同属一个同源群.通过搜索水稻的同源BAC(bacterial artificialchromosome)和PAC(P1 artificial chromosome)克隆,推测另外11个克隆的染色体位置,其中4个克隆可能位于第四染色体同源群.用RNA点杂交对11个克隆进行表达谱分析,其中8个克隆在不育株的小穗和花药中呈上调表达.     

根施甜菜碱对干旱胁迫下小麦幼苗类囊体膜组分和功能的影响

干旱胁迫造成两小麦品系类囊体膜上的单半乳糖脂甘油二酯(MGDG)、双半乳糖脂甘油二酯(DGDG)、磷脂酰胆碱(PG)以及叶绿素含量显著下降,甜菜碱预处理能缓解这些组分的下降.干旱胁迫下,抗旱型小麦品系HF9 70 3的硫代异鼠李糖甘油二酯(SQDG)、反式十六碳-烯酸[16:1(3t)]含量显著上升,MGDG中亚麻酸(18:3)相对含量显著下降;而干旱敏感型品系SN215953则表现为SQDG、16:1(3t)含量显著下降,MGDG中脂肪酸变化不明显,这可能是两个小麦品系抗旱性差异的重要原因之一;甜菜碱处理能显著减小干旱处理与对照之间的差异,且对SN215953的作用较HF9703大.另外,干旱胁迫引起类囊体膜上Ca2 -ATPase活性、Hill反应活性及叶片净光合速率下降,外源甜菜碱能缓解其下降趋势.     

盐胁迫下小麦甜菜碱和脯氨酸含量变化

运用高效液相色谱-质谱(HPLC-MS)联用技术分析了耐盐性强、中、弱3个小麦品种SW12、宁春4号和中国春苗期5个NaCl浓度胁迫下甜菜碱和脯氨酸含量的变化.方差分析表明盐胁迫下3个小麦品种之间甜菜碱的含量差异达到极显著水平(P＜0.01),SW12的含量最高,宁春4号次之,中国春最低,与小麦耐盐性表现相一致;脯氨酸在叶片中的含量差异不显著,在根中宁春4号和中国春的含量有显著差异(P＜0.05).结果表明:小麦叶和根中甘氨酸甜菜碱含量与小麦盐胁迫呈正相关,是小麦体内抵御盐胁迫的渗透调节物质之一,可作为小麦耐盐性鉴定指标.     

梨种质资源主要描述标准比较分析

介绍了国内外6个梨种质资源描述标准,并对其主要形态特征与农艺性状描述符进行了归纳整理;分析了各描述符标准的层次结构特征、生物胁迫与非生物胁迫评价内容以及描述符编码方式;指出了制定我国梨相关标准借鉴之处.     

河北省西瓜枯萎病菌致病性分化及其RAMS分析

本文对50个西瓜枯萎病菌株,(其中46个来自河北省石家庄、保定、唐山等12个西瓜种植区的代表菌株)进行了致病性测定、RAMS(Random amplified microsatellites)扩增和致病类型与RAMS类群的相关性分析。根据鉴别寄主对不同菌株的抗感反应,将50个菌株划分为3个不同的生理小种,即0号、1号和2号生理小种,分别占供试菌株的18%、64%和18%;21个RAMS引物对供试菌株扩增出188条带,其中多态性带134条,占总带数的71%。基于RAMS标记聚类分析,50个菌株被划分为3个类群(RAMSGroups,RGs)。RGI包含来自不同地区的41个菌株,以1号生理小种为主(32个),占该类群的78.1%;RGII包括来自保定、唐山和新疆的3个菌株,均为0号生理小种;RGIII包括张家口、石家庄、保定等地的6个2号生理小种菌株。RAMS类群与生理小种之间存在一定相关性,与菌株的地理来源关系不明显。     

Antiporter Gene from Hordum brevisubulatum （Trin.） Link and Its Overexpression in Transgenic Tobaccos

A vacuolar Na^ /H^ antiporter cDNA gene was successfully isolated fromHordeum brevisubulatum (Trin.) Link using the rapid amplification ofcDNA ends (RACE) method. The gene was named HbNHXI and was found to consist of 1 916 bp encoding a predicted polypeptide of 540 amino acids with a conserved amiloride-binding domain. Phylogenetic tree analysis of the Na^ /H^ antiporters showed that the HbNHXI gene shares 55.3%-74.8% similarity with the vacuolar-type Na^ /H^ antiporters. Transgenic tobaccos that contain the HbNHXI gene, integrated by forward insertion into the tobacco genome, were obtained via Agrobacterium tumerfaciens and characterized for the determination of the concentration of Na^ and K^ ions, as well as proline, in the presence of 300 mmol/L NaCl. The T1 transgenic plants showed more tolerance to salt and drought than did wild-type plants. Our data suggest that overexpression of the HbNHXI gene could improve the tolerance of transgenic tobaccos to salt and drought through the function of the vacuolar Na^ /H^ antiporter.     

Spatial heterogeneity and population risk analysis of cotton bollworm, Helicoverpa armigera, in China

In this study, semivariance was used to quantitatively measure the spatial heterogeneity for the egg population of cotton bollworm during a growing season. The typical characteristic parameters of theoretical semivariance models against lag distances were applied to measure components of spatial heterogeneity： trend, range, spatial dependence, and the strength of spatial dependence. Then, kriging interpolation was used to evaluate the population risk of cotton bollworm exceeding economic thresholds. From early June through early September, the population densities were sampled 10 times in the study field. Results showed that the spatial patterns were related to population density. For its low-density population, the spatially heterogeneous trends were usually of spherical shapes; but for highdensity ones, the trends shifted to Gaussian shapes. The spatial dependence appeared at varied distances ranging from 52 meters to 936 meters, and the spatial dependence was in the range of 0.39-288.60, which changed with population densities. While having high heterogeneity, the strength of spatial dependence became much stronger. Results of population risk analysis showed that there was a high risk during its early stages, especially in mid-June. In August, population risk was so low that it did not need to be controlled.