辣椒基因组DNA两种提取方法的比较

采用SDS法和CTAB法提取新鲜辣椒幼叶的基因组DNA,用核酸蛋白仪检测法、琼脂糖凝胶电泳法和PCR扩增法对两种方法提取的DNA样品分别进行检测,核酸蛋白仪检测表明:SDS法得到的DNAOD260/OD280均大于2.0,说明蛋白质去除彻底,但RNA未除干净;CTAB法得到的DNAOD260/OD280均为1.8～2.0,说明蛋白质、多糖、RNA完全去除。琼脂糖凝胶电泳表明:SDS法提取的DNA有两条带,说明样品中仍含有未被除去的多糖及其他一些次生代谢物质,RNA也有残留;CTAB法提取的DNA只有一条清晰整齐的主带,有效地去除了辣椒幼叶中的多糖及其他次生代谢物质,RNA也降解完全。PCR扩增法显示:SDS法和CTAB法提取的DNA样品均可进行PCR扩增,也可用作SRAP研究,但CTAB法提取的样品扩增出的条带比较清晰。结果表明:CTAB法提取的DNA含量高,纯度高,能够满足后续分子生物学研究的需要。     

植物总DNA的提取方法的改进

改进了以CTAB法为基础的植物总DNA的提取方法.通过对实验材料的暗处理、4℃放置、加入蛋白酶K、提高提取缓冲液中β-巯基乙醇用量,增加氯仿/异戊醇的量和使用次数,以及缩短异丙醇沉淀DNA的时间,成功地从富含酚类和多糖的榕树叶片中提取到高质量的总DNA.     

Probabilistic Nonadaptive and Two-Stage Group Testing with Relatively Small Pools and DNA Library Screening

We use a simple, but nonstandard, incidence relation to construct probabilistic nonadaptive group testing algorithms that identify many positives in a population with a zero probability of yielding a false positive. More importantly, we give two-stage modifications of our nonadaptive algorithms that dramatically reduce the expected number of sufficient pools. For our algorithms, we give a lower bound on the probability of identifying all the positives and we compute the expected number of positives identified. Our method gives control over the pool sizes. In DNA library screening algorithms, where relatively small pools are generally preferred, having control over the pool sizes is an important practical consideration.     

地梢瓜甙对神经细胞脂质过氧化反应和DNA损伤的保护作用实验研究

通过采用离体乳鼠大脑皮层神经元的培养 ,观察了谷氨酸、H2 O2 对皮层神经元的损伤及地梢瓜甙的抗损伤作用。结果表明 :地梢瓜甙组神经元DNA断裂率明显降低 ,且可降低损伤后皮层神经元的MDA水平。说明地梢瓜甙能够抑制脂质过氧化反应 ,对神经元具有保护作用     

原位缺口平移法在检测睾丸组织凋亡细胞中的应用

研究原位缺口平移技术在显示睾丸细胞凋亡中的应用．方法：采用原位缺口平移技术检测大鼠睾丸组织中DNA断裂，显示细胞凋亡．结果：在睾丸组织中出现阳性标记细胞，在10μm厚的切片上，每条精曲小管可见0－3个阳性标记细胞．结论：该方法可用于不同主理和病理条件下睾丸细胞凋亡的研究     

从海鱼加工下脚料中提取核酸的试验(Ⅱ)--从鱼白中提取核酸及产物纯度分析和组分鉴定

对地产海鱼加工下脚料之一-鱼白中核酸的提取方法，产品纯度测定和组分鉴定方法进行一些探索，结果显示，DNA粗产物得率为4.62%，DNA质量分数为4.77%，RNA粗产物得率为1.98%，RNA质量分数4.06%，提取方法基本可行。     

大白菜RAPD扩增体系的优化研究

以大白菜 341 1 - 7自交系为材料 ,使用 PE公司生产的 Thermal Cycler480型 PCR仪 ,对影响大白菜 RAPD扩增的因素进行了研究 ,确定了模板 ,Mg2 +,d NTPs,引物和 Taq DNA聚合酶的适宜浓度和最佳的循环次数 .实验结果表明 ,在 2 5μL反应体系中使用 2 0— 60 ng的模板 DNA,1 .5— 2 .0 mmol/L 的 Mg2 +,0 .1 5— 0 .2 5 mmol/L d NTPs,0 .8— 1 .0 μmol/L随机引物 ,1 .0— 1 .5 U Taq DNA聚合酶 ;在 94℃下预变性 5 min后执行 94℃ 1 min,37℃ 1min,72℃ 2 min,35个循环 ,最后 72℃再延伸 5 min的条件下 ,大白菜的 RAPD扩增效果较好     

DNA疫苗的研究进展

回顾了DNA疫苗的发展历程，综述了DNA疫苗基础研究和应用研究的新进展，探讨了DNA疫苗的优越性、存在问题及发展前景。     

两步法进行粘端—平端连接

优化DNA重组的反应条件 ,将粘端一平端连接分两步进行 ,大大提高了DNA重组的效率     

An equivalence test for comparing DNA sequences

The practice of sequence alignment is constantly oscillating between the risk of overlooking important structure and that of discovering any arbitrarily defined kind of structure anywhere. On the other hand, the use of a condensed consensus sequence may lead to a substantial loss in valuable information. While adopting a Mahalanobis‐type index we allow for a certain degree of uncertainty in the measurements. This uncertainty may be caused by inaccurate measurements or ambiguity. In this paper, we test the similarity between DNA sequences within the framework of equivalence testing, accounting for both variances and covariances between frequencies of nucleotides. Statistical methods for testing equivalence were first developed in the context of pharmacokinetics and later extended to the field of clinical trials. Nowadays, (bio)equivalence tests seem to be less frequently used outside the drug testing field, including statistical genetics. Copyright © 2005 John Wiley & Sons, Ltd.