水稻条纹病毒的分子生物学

综述了近年来国内外有关水稻条纹病毒在基因组结构、功能、复制、转录、表达策略及其分类地位、病毒分子变异和病害控制策略以及进化上的亲缘关系等方面的最新研究进展 ,并就如何进一步开展深入研究进行了讨论     

小麦品种高分子量谷蛋白亚基的组成分析

利用SDS—PAGE电泳分析了49个国内外小麦品种的高分子量谷蛋白亚基组成。结果表明：39个国内小麦品种中,5 10亚基的频率这64％。不同面筋强度的小麦品种高分子量麦谷蛋白亚基组成存在明显差异,强筋品种含有较多的1或2^*、7 8或17 18或14 15、5 10亚基组合类型,亚基总评分一般为9～10分;弱筋品种含有较多的Null、7 9、2 12亚基组合类型,亚基总评分一般为5～8分;中筋品种则处于中间类型,亚基总评分差异较大。然而,有些中筋甚至弱筋小麦品种也含有5 10亚基或者一般强筋品种才具有的亚基组合,有的强筋小麦品种反而没有5 10亚基,说明低分子量的谷蛋白亚基和醇溶蛋白质组分对面筋强度也具有重要作用。     

小麦高分子量谷蛋白1Dx5亚基特异PCR标记

本研究为1Dx5亚基基因(Glu—Dl-1b)设计了一对特异引物，对HMW—GS在Glu—Dx1位点已知的11个小麦品种进行了PCR扩增，以检测PCR标记的准确性。结果表明，凡具有1Dx5亚基的4个品种都能扩增出一条450bp的特异带，而其它品种则不能扩增出这一特异带．与HMW—GS的蛋白质电泳结果一致。用这一特异标记对山东省推广种植面积较大的35个品种进行PCR检测．发现仅有9个品种携带1Dx5基因，占待测材料总数的25．7％，明显低于北美小麦品种。研究发现，与蛋白质的HMW—GS标记相比．PCR标记更快速、简便、准确。     

聚合物分子尺寸大小及其与岩石孔喉尺寸配伍关系的试验研究

为了探索和验证聚合物分子尺寸与岩石孔喉尺寸的配伍关系,以河南油田东部老油区稀油油田为例,应用数学方法、微孔滤膜过滤方法和动态光散射方法,对开展聚合物驱条件下拟使用的聚合物的分子尺寸进行试验测定,得到了双河油田不同渗透率岩石能够匹配的聚合物分子量。     

优质抗病高配合力中籼两用核不育系隆科638S的选育及应用

利用传统育种技术与分子标记辅助选择技术有机结合,成功培育出了株型理想、不育转换起点温度低于23.5℃、育性稳定、异交性好、配合力强的两用核不育系隆科638S,于2014年通过湖南省品种审定。全基因组重测序分析结果表明,隆科638S含有约56.0%的早籼稻遗传背景,以及约8.7%的粳稻遗传背景,为充分利用“早晚生态型间和籼粳亚种间”双重杂种优势奠定了遗传基础。依据分子设计和杂种优势群理论,按“双亲抗性基因互补”和“双亲品质基因一致性”配组原则,高效培育出一批绿色、优质、广适、高产的隆两优系列品种,迅速成为我国南方杂交水稻主栽品种,推动了长江流域杂交中籼品种的更新换代。     

果蔬类多孔介质干燥传质过程的分子动力学模拟

果蔬类多孔介质内部水中溶解有大量的营养物质(溶质),在干燥过程中溶质的迁移与湿分的传递同时进行,其内部微孔内的干燥传质机理尚不明确。为了揭示果蔬类多孔介质干燥过程中内部溶液的迁移机理,确定果蔬微孔结构特性对干燥传质过程的影响规律,该研究采用分子动力学方法模拟研究了果蔬类多孔介质微孔道中的干燥传质过程,构建了光滑壁面溶液扩散过程模型与粗糙壁面溶液扩散过程模型。模拟过程采用SPC/E水分子模型,选取OPLS-AA全原子力场和正则系综,溶液势函数选用静电库伦相互作用与Lennard-Jones相互作用,中心水分子的初始速度由高斯分布给出,采用Velocity-Verlet算法,用SHAKE算法固定水分子,x、y方向施加周期性边界条件,z方向上施加固定壁面边界条件。从分子水平模拟分析了果蔬类多孔介质内部溶液的扩散过程,并以马铃薯的热风干燥试验结果进行模型的验证。得出试验值与KCl溶液粗糙壁面模型的模拟值最为接近,其最大相对误差为17.39%;与纯水模型的模拟值相差最大,说明溶质的存在对水分扩散系数的影响不可忽略,且粗糙壁面模型更接近于真实孔道结构。从径向分布函数分布可以看出K+、Cl-对水分子...     

Fractionation of soil humic acids by preparative polyacrylamide gel electrophoresis in the presence of concentrated urea

To separate soil humic acids (HAs) into their constituents and characterize them, polyacrylamide gel electrophoresis (PAGE) was carried out in the presence of 7 M urea using a preparative electrophoresis system. Two types of soil HAs were fractionated into nine fractions by PAGE. The dark-colored constituents were recovered from the electrophoretic fractions by precipitation on acidification, and the brown-colored constituents dissolved in the acidic solution of fast-moving fractions were recovered by adsorption onto DAX-8 resin. High-performance size-exclusion chromatography (HPSEC) confirmed that the constituents of the HAs were separated based on their molecular size by PAGE. The dark-colored constituents exhibited higher degrees of humification than did the corresponding unfractionated HAs, except for the constituents remaining in the electrophoretic gels at the end of electrophoresis. Diffuse reflectance infrared spectroscopy revealed that the chemical properties of the dark-colored constituents changed regularly: the content of carboxyl groups decreased and the proportions of proteinous, aliphatic and polysaccharide moieties increased with increasing molecular size. The humification degrees of the constituents adsorbed onto DAX-8 resin were considerably lower than those of the corresponding unfractionated HAs. The chemical properties of the DAX-8-adsorbed constituents were different from those of the dark-colored constituents. Observation of electrophoretic fractions under blue light (470 nm) and HPSEC with fluorescence detection at an excitation wavelength of 460 nm and an emission wavelength of 520 nm showed that green fluorescent substances were largely concentrated in the smallest molecular size fractions and were partitioned into both the dark-colored precipitates and DAX-8-adsorbed fractions. The proportion of organic carbon recovered by precipitation and adsorption onto DAX-8 resin was 45–63%, indicating that substantial parts of the HA constituents were missing. The unrecovered constituents were considered to be acid-soluble, nearly colorless substances. The dissociation of the acid-soluble constituents from the acid-insoluble dark-colored constituents during the preparative PAGE of soil HAs was ascribed to disruption of hydrogen bonding and hydrophobic interactions caused by concentrated urea.     

北美森林新病害——山毛榉叶线虫病

2012年,北美地区发生了一种由山毛榉李氏垫刃线虫麦肯恩亚种(Litylenchus crenatae mccannii)引起的森林新病害——山毛榉叶线虫病,病情蔓延迅速,已扩散至美国和加拿大30个县。病原为害山毛榉属植物,可造成病树成片死亡。由于山毛榉是北美温带阔叶林的主要构成树种和重要用材树种,新病害已引起美国农业部的高度重视并采取积极的应对措施。我国分布5种山毛榉属植物(均为特有种),是我国南方森林的主要组成树种。鉴于我国每年从北美进口大量山毛榉木材,病原线虫存在随进境木材传入国内的巨大风险。因此,检疫部门应开展风险评估,口岸应针对性开展山毛榉叶线虫病的检测。本文主要介绍了山毛榉叶线虫病的发生历史、分布范围、为害症状、病原线虫形态学特征、生活史、传播途径、分子检测方法等方面的信息,以期为口岸检疫工作提供参考。     

Characterization of Fusarium population associated with wilt of jojoba in Israel

Fusarium wilt, caused by Fusarium oxysporum, is a major disease of jojoba, causing serious economic losses. This study was aimed at characterizing the Fusarium populations associated with jojoba in Israel. Fifty Fusarium isolates used in this study included 23 isolates from the 1990s (“past”) and 27 recently isolated (“recent”). All the isolates were characterized by arbitrarily primed (ap)-PCR and 16 representatives were additionally delineated using multilocus (tef1, rpb1, rpb2) phylogeny and evaluated for their pathogenic potential. Consequently, 88% of the isolates were identified and characterized to the F. oxysporum species complex. The remaining 12% grouped within the F. fujikuroi, F. solani, and F. redolens species complexes. Variations in the infection rate (16.7%–100%), disease symptoms (0.08–1.25, on a scale of 0–3), and fungal colonization index (0.67–2.17, on a scale of 0–4) were observed within the tested isolates, with no significant differences between the past and recent isolates. The representative isolates were assigned to 11 groups based on ap-PCR. Pathogenicity tests showed that isolates from Groups II, IV, and V were the most aggressive, whereas isolates from Groups III, VIII, and IX were the least aggressive. Among the tested isolates, F. oxysporum sensu lato was the most aggressive, followed by F. proliferatum, while F. nygamai was the least aggressive. This study demonstrates the complexity and genetic diversity of Fusarium wilt on jojoba in Israel, indicating possible multiple introductions of infected germplasm into the country.