油菜籽提取物清除活性氧作用研究

自由基是一种带有未成对电子的分子或离子,具有很高的反应活性,可对机体产生毒害,破坏生物大分子,影响细胞活性.如果自由基被中途清除,就可能中断此反应[1].科学研究表明,自由基与免疫、疾病、衰老等许多病理生理现象都有密切的关系.     

卡瓦胡椒及胡椒的RAPD聚类分析

目的：通过RAPD分析搞清楚卡瓦胡椒与胡椒及胡椒属其它近缘野生种的亲缘关系。方法和结果：采用随机引物80条进行筛选,用从80条随机引物中入选的20条引物,对卡瓦胡椒和胡椒属共计28份材料进行RAPD扩增,均能产生清晰的扩增谱带。重复1—2次,结果稳定可靠。20个引物共扩增出170个条带,其中多态性条带有20条,占总扩增条带数的12％。RAPD分析结果显示在相似系数0．36处对28份种质可划分为6个类型,其中卡瓦胡椒被单独聚为一类,说明卡瓦胡椒与胡椒及其它近缘野生种的亲缘关系有一定的距离。     

双价抗病基因导入籽瓜的遗传转化研究

以籽瓜主栽品种新籽瓜2号、五原籽瓜等为研究材料,用苗龄1-3d的子叶切块作外植体,不定芽诱导培养基为MS 6-BA2mg/L IBA 0.1mg/L,芽伸长培养基为MS KT0．2mg／L,诱导生根的培养基是MS IAA0．5mg／L。籽瓜遗传转化研究结果表明农杆菌感染时间以10min,共培养时间以2d为合适。共获得抗卡那霉素100mg／L的试管苗41个,PCR检测呈阳性的有15株,转化率为34．9％。该研究初步建立了籽瓜的遗传转化体系和转化体的检测体系。     

Phylogenetic positions of several amitochondriate protozoa

Several groups of parasitic protozoa, as represented by Giardia, Trichomonas, Entamoeba and Microsporida, were once widely considered to be the most primitive extant eukaryotic group―Archezoa. The main evidence for this is their ‘lacking mitochondria’ and possessing some other primitive features between prokaryotes and eukaryotes, and being basal to all eukaryotes with mitochondria in phylogenies inferred from many molecules. Some authors even proposed that these organisms diverged before the endosymbiotic origin of mitochondria within eukaryotes. This view was once considered to be very significant to the study of origin and evolution of eukaryotic cells (eukaryotes). However, in recent years this has been challenged by accumulating evidence from new studies. Here the sequences of DNA topoisomerase II in G. lamblia, T. vaginalis and E. histolytica were identified first by PCR and sequencing, then combining with the sequence data of the microsporidia Encephalitozoon cunicul and other eukaryotic groups of different evolutionary positions from GenBank, phylogenetic trees were constructed by various methods to investigate the evolutionary positions of these amitochondriate protozoa. Our results showed that since the characteristics of DNA topoisomerase II make it avoid the defect of ‘long-branch attraction’ appearing in the previous phylogenetic analyses, our trees can not only reflect effectively the relationship of different major eukaryotic groups, which is widely accepted, but also reveal phylogenetic positions for these amitochondriate protozoa, which is different from the previous phylogenetic trees. They are not the earliest-branching eukaryotes, but diverged after some mitochondriate organisms such as kinetoplastids and mycetozoan; they are not a united group but occupy different phylogenetic positions. Combining with the recent cytological findings of mitochondria-like organelles in them, we think that though some of them (e.g. diplo-monads, as represented by Giardia) may occupy a very low evolutionary position, generally these organisms are not as extremely primitive as was thought before; they should be poly-phyletic groups diverging after the endosymbiotic origin of mitochondrion to adapt themselves to anaerobic parasitic life.     

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.     

应用体内诱导抗原技术筛选结核分枝杆菌体内表达基因

为寻找新型抗结核药物靶标 ,采用体内诱导抗原技术筛选结核分枝杆菌的体内诱导基因。首先构建了结核分枝杆菌基因组质粒表达文库 ,库容量为 1 0 2× 1 0 5CFU。再用经过结核分枝杆菌和大肠杆菌的裂解产物吸附过的结核病人血清 ,通过原位免疫印迹来筛选基因组表达文库 ,共获得 1 6个阳性克隆。对阳性克隆进行测序和生物信息学分析 ,发现该 1 6个阳性克隆可能包含 2 2个开放阅读框 (ORF)。按照功能将其分为 7类基因 :脂类代谢 2个、信号途径 5个、PE/PPE蛋白家族 2个、中间产物与能量代谢 6个、细胞壁与细胞处理 1个、假想蛋白 4个和与牛型分枝杆菌定向进化同源的 2个 ,其中部分基因可能与毒力相关 ,可以作为候选药物靶标     

柯萨奇病毒致病毒性心肌炎的细胞凋亡研究

病毒性心肌炎是心血管系统的常见病与多发病。对病毒引起的心肌细胞病理改变及机制的探讨一直是该领域的研究热点。自从科学家报道“凋亡”这种细胞死亡形式以来,为病毒性疾病研究者找到了一条新的研究途径。此后,许多国内外基础医学研究者通过不同方法对细胞受到病毒侵袭后的死亡形式进行研究。目前认为,病毒性心肌炎急性期机体心肌组织的确存在凋亡,     

分子运动性预测麻栎种子离体胚轴适宜贮藏条件初探

应用电子顺磁共振波谱仪和自旋标记技术,以硝基氧探针为标记物,检测了室温下麻栎种子离体胚轴脱水过程中分子运动性的变化。发现含水量0.7gH2O/gDW至0.64gH2O/gDW范围是细胞质粘度的转折区域,低于这个含水量区域,细胞质粘度骤然上升,推测这个区域是室温下保存离体胚轴的适宜含水量下限。通过变温电子顺磁共振波谱测定,找到离体胚轴含水量在0.43gH2O/gDW至1.02gH2O/gDW范围内,分子运动性的临界温度和玻璃态相变温度所在区间。根据分子运动性随温度变化的规律,预测含水量为0.69gH2O/gDW的麻栎种子离体胚轴适宜贮藏温度约为-50℃。     

四眼斑水龟低温胁迫条件下体重与形态特征的初步研究

在海南的正常温度下,四眼斑水龟(Sacalia quadriocellata)在人工饲养环境中无冬眠现象,也未观察到繁殖行为。为研究冬眠对四眼斑水龟繁殖的影响,于2004年12月~2005年2月对其进行低温胁迫实验。选取29只成体四眼斑水龟分成2组,实验组9♀5♂共14只进行低温处理,在8·46±1·61℃干燥环境中保持32天;对照组10♀5♂共15只在正常条件下饲养。结果表明:低温胁迫后,实验组平均体重减小8·68±2·45%,雌雄差异不显著;雄性个体背甲宽从8·55±0·26cm减小到8·46±0·22cm,差异显著(P<0·05);雌性个体背甲长从12·97±0·80cm减小到12·94±0·81cm,差异显著(P<0·05);雌雄四眼斑水龟甲壳表面积相对低温胁迫前均减小;对照组龟养殖于常温下,甲壳无显著变化,两组龟体重变化量差异极显著(P<0·01)。影响失重率主要因素是胁迫时间,环境温度对失重呈显著线性正相关(r=0·811,P<0·05);形态特征的变化可能与繁殖机制、代谢有关。