原位杂交中鲑鱼精DNA处理方法探究

采用机械打断/沸水浴和超声波处理两种方法对原位杂交中的封闭DNA——鲑鱼精DNA进行了断裂处理。分别探讨了不同的吹打次数、煮沸时间和超声波处理时间对鲑鱼精DNA片段大小的影响,并且对机械打断/沸水浴和超声波处理两种方法结果进行了比较分析。研究结果表明在煮沸时间20min时,吹打次数可根据所需原位杂交片段大小进行调整;超声波适宜打断时间为20min。     

Uncertainties in the CIIT Model for Formaldehyde-Induced Carcinogenicity in the Rat: A Limited Sensitivity Analysis–I

Scientists at the CIIT Centers for Health Research (Conolly et al., 2000, 2003; Kimbell et al., 2001a, 2001b) developed a two-stage clonal expansion model of formaldehyde-induced nasal cancers in the F344 rat that made extensive use of mechanistic information. An inference of their modeling approach was that formaldehyde-induced tumorigenicity could be optimally explained without the role of formaldehyde's mutagenic action. In this article, we examine the strength of this result and modify select features to examine the sensitivity of the predicted dose response to select assumptions. We implement solutions to the two-stage cancer model that are valid for nonhomogeneous models (i.e., models with time-dependent parameters), thus accounting for time dependence in variables. In this reimplementation, we examine the sensitivity of model predictions to pooling historical and concurrent control data, and to lumping sacrificed animals in which tumors were discovered incidentally with those in which death was caused by the tumors. We found the CIIT model results were not significantly altered with the nonhomogeneous solutions. Dose-response predictions below the range of exposures where tumors occurred in the bioassays were highly sensitive to the choice of control data. In the range of exposures where tumors were observed, the model attributed up to 74% of the added tumor probability to formaldehyde's mutagenic action when our reanalysis restricted the use of the National Toxicology Program (NTP) historical control data to only those obtained from inhalation exposures. Model results were insensitive to hourly or daily temporal variations in DNA protein cross-link (DPX) concentration, a surrogate for the dose-metric linked to formaldehyde-induced mutations, prompting us to utilize weekly averages for this quantity. Various other biological and mathematical uncertainties in the model have been retained unmodified in this analysis. These include model specification of initiated cell division and death rates, and uncertainty and variability in the dose response for cell replication rates, issues that will be considered in a future paper.     

Carcinogenic Mixtures

Human populations are generally exposed simultaneously to a number of toxicants present in the environment, including complex mixtures of unknown and variable origin. While scientific methods for evaluating the potential carcinogenic risks of pure compounds are relatively well established, methods for assessing the risks of complex mixtures are somewhat less developed. This article provides a report of a recent workshop on carcinogenic mixtures sponsored by the Committee on Toxicology of the U.S. National Research Council, in which toxicological, epidemiological, and statistical approaches to carcinogenic risk assessment for mixtures were discussed. Complex mixtures, such as diesel emissions and tobacco smoke, have been shown to have carcinogenic potential. Bioassay-directed fractionation based on short-term screening test for genotoxicity has also been used in identifying carcinogenic components of mixtures. Both toxicological and epidemiological studies have identified clear interactions between chemical carcinogens, including synergistic effects at moderate to high doses. To date, laboratory studies have demonstrated over 900 interactions involving nearly 200 chemical carcinogens. At lower doses, theoretical arguments suggest that risks may be near additive. Thus, additivity at low doses has been invoked as as a working hypothesis by regulatory authorities in the absence of evidence to the contrary. Future studies of the joint effects of carcinogenic agents may serve to elucidate the mechanisms by which interactions occur at higher doses.     

MP-120工作站批量提取法医样本DNA

本文运用MP-120自动化DNA提取仪对72份血斑检材进行DNA提取扩增,荧光检测信号均值在200-3000RFU之间,表明所建立的MP-120工作操作程序在血斑的批量提取方面具有较高的成功率、稳定性和均一性,适用于法医DNA数据库的建立和案件中血斑样本的批量提取。     

琼脂糖凝胶电泳实验技术研究

通过对细叶榕（F.microcarpa）基因组DNA的琼脂糖凝胶电泳检测,针对琼脂糖凝胶电泳中出现的常见问题,对琼脂糖凝胶电泳实验技术进行深入研究,对从事分子生物学实验工作者具有指导作用.     

三七、肉苁蓉、枸杞和黄芪总DNA提取方法的研究

本实验研究以中药材三七的叶子、肉苁蓉的茎、宁夏枸杞的果实、黄芪的根为材料,对改进CTAB法、SDS法提取的基因组DNA进行了比较研究.由于四种中药材所含成分有很大的差别,所得到的DNA样品在直观上也有很大的区别.结果表明,改良CTAB法适合四种中药材基因组DNA的提取.     

创新型文化及其构建——基于企业DNA理论的探讨

创新是企业获得竞争优势的源泉,丰硕的创新成果孕育于企业的创新文化。企业文化对创新活动既可能是支持性,也可能会产生消极的阻碍。创新型文化是一种激发、培育和实现创新的文化,创新型文化的形成必须有稳定的基础。创新文化的特征主要有:共同愿景和目标、信任与开放的氛围、鼓励冒险的精神、团队工作的方式、高层领导的支持和激励、宽容失败的态度等。根据企业DNA理论,创新型文化的建设要基于组织架构,决策权,信息传导和激励机制诸方面展开。     

存世曹氏族谱与曹操后裔无关——与复旦“曹操墓人类基因调查的历史学研究”课题组商榷

据陈寿所撰<三国志>载,曹操之父曹嵩乃中常侍曹腾之养子,其"生出本末"已不可考.春秋已降,就一直有"同姓不婚"的禁忌,夏侯与曹氏世为婚姻,故"曹氏源于夏侯氏"一说不能成立.目前国内所藏的家谱,宋代的极为罕见.大多数图书馆所藏的谱牒多为清代或民国时所修,明代族谱已不易见.存世曹氏族谱所录之远祖系唐末宋初人,与曹操时代相距近八百年.又由于历史上盛行冒姓、赐姓、改姓、认领养子、伪造谱牒之风,这就使今人寻求曹操后裔几无可能.     

The Levels of Cortisol,Oxidative Stress,and DNA Damage in the Victims of Childhood Sexual Abuse: A Preliminary Study

In this study we aimed to investigate serum cortisol, oxidative stress, and DNA damage in children who are sexual abuse victims. The study included 38 children who sustained child sexual abuse and 38 age- and gender-matched children who did not have a history of trauma. Cortisol levels reflecting the status of the hypothalamic-pituitary-adrenal axis, anti-oxidant enzymes glutathione peroxidase, superoxide dismutase, natural anti-oxidant coenzyme Q, and 8-hydroxy-2-deoxyguanosine as the indicator of DNA damage were analyzed in serum samples using the enzyme linked immunosorbent assay method. Cortisol levels were significantly higher in the child sexual abuse group compared to the control group. There were no significant differences between the groups in terms of oxidative stress and DNA damage. Cortisol and 8-hydroxy-2-deoxyguanosine levels decreased as the time elapsed since the sexual abuse increased. Coenzyme Q level was lower in victims who sustained multiple assaults than in the victims of a single assault. Cortisol and superoxide dismutase levels were lower in the victims of familial sexual abuse. Decreases in cortisol and 8-hydroxy-2-deoxyguanosine levels as time elapsed may be an adaptation to the toxic effects of high cortisol levels over a prolonged period of time. Child sexual abuse did not result in oxidative stress and DNA damage; however, some features of sexual abuse raised the level of oxidative stress.     

A Bayesian approach to inference about a change point model with application to DNA copy number experimental data

In this paper, we study the change-point inference problem motivated by the genomic data that were collected for the purpose of monitoring DNA copy number changes. DNA copy number changes or copy number variations (CNVs) correspond to chromosomal aberrations and signify abnormality of a cell. Cancer development or other related diseases are usually relevant to DNA copy number changes on the genome. There are inherited random noises in such data, therefore, there is a need to employ an appropriate statistical model for identifying statistically significant DNA copy number changes. This type of statistical inference is evidently crucial in cancer researches, clinical diagnostic applications, and other related genomic researches. For the high-throughput genomic data resulting from DNA copy number experiments, a mean and variance change point model (MVCM) for detecting the CNVs is appropriate. We propose to use a Bayesian approach to study the MVCM for the cases of one change and propose to use a sliding window to search for all CNVs on a given chromosome. We carry out simulation studies to evaluate the estimate of the locus of the DNA copy number change using the derived posterior probability. These simulation results show that the approach is suitable for identifying copy number changes. The approach is also illustrated on several chromosomes from nine fibroblast cancer cell line data (array-based comparative genomic hybridization data). All DNA copy number aberrations that have been identified and verified by karyotyping are detected by our approach on these cell lines.