分子生物学在年龄推断中的研究进展

年龄推断是法医学研究与实践的重点和难点内容之一。目前,年龄推断主要依据骨龄、牙龄等形态学方法,但误差较大、影响因素较多。近年来,随着分子生物学理论与技术的发展,研究者发现某些细胞分子水平与年龄密切相关。本文就目前细胞分子水平与年龄关系的研究进展进行综述。     

FluMag-SELEX技术体外筛选识别氯胺酮的DNA适体

目的 利用FluMag-SELEX技术筛选出能特异性识别氯胺酮的DNA适体. 方法 体外合成78 bp的随机ssDNA文库,氯胺酮作为靶分子,表面修饰甲苯磺酰基的磁珠作为固相载体筛选特异性识别氯胺酮的适体.经过13轮筛选后进行DNA克隆测序,并进行一、二级结构分析.通过对荧光强度的分析检测适体的亲和性、特异性和Kd值. 结果 获得2条ssDNA适体Apt#4和Apt#8,能够特异性地与靶分子氯胺酮结合,Kd值分别为0.59和0.66 μmol/L.二级结构预测以茎环和G-四聚体为主,茎结构可能是适体结构稳定的基础,环和G-四聚体结构可能是与氯胺酮特异性结合的关键. 结论 FluMag-SELEX技术可以较好地提高适体的筛选效率,得到能特异性识别氯胺酮的DNA适体,有望用于氯胺酮的快速检测.     

应用常染色体STR预测近亲关系调查案件

目的通过两起案例讨论利用常染色体STR全不同基因座数预测血亲关系,从而快速、高效地侦破疑难案件。方法应用全不同基因座数预测血亲关系,包括预测叔侄、祖孙或半同胞关系;应用IBS评分预测全同胞关系;结合家系调查、侦查信息调查案件。结果这种侦查模式有助于预测目标的同胞、叔侄、祖孙等血亲关系人,可充分挖掘样本的亲缘遗传信息,指导案件侦查方向。结论应用常染色体STR全不同基因座计数法和共有等位基因计数法可帮助预测血亲关系,能为调查案件提供新思路,对侦查更具指导意义。     

24个Y-STR基因座在云南苗族人群中的序列多态性

目的研究法医学常用Y-STR基因座在中国云南苗族男性个体中的序列多态性。方法采用M48磁珠提取纯化试剂盒提取样本DNA,使用ForenSeqTM DNA Signature Prep试剂盒制备文库,Miseq FGx平台进行测序,ForenSeq Universal Analysis v1.2.1软件进行数据分析,用Arlequin v3.5软件计算各Y-STR基因座相关的统计学参数,将Y-STR基因座长度多态性与序列多态性进行比较。结果108名云南苗族个体中共检出106种单倍型,总体单倍型多样性(HD)和Y-STR分型系统的分辨能力(DC)分别为0.9993和0.9815。24个Y-STR基因座共检出204个基因,基因多样性(gene diversity,GD)值为0.2177~0.9481,15个Y-STR基因座的GD值大于0.6。DYF387S1、DYS390、DYS389II、DYS437、DYS438、DYS448、DYS612基因座存在长度相同的基因核心序列不同的情况。结论该24个Y-STR基因座在云南苗族男性人群中具有丰富的遗传多态性。研究结果可为Y-STR数据库的建立、群体遗传学和法医学实践提供参考。     

浅谈《病原生物与免疫学》对高职护理专业学习的重要性

高职高专层次开设的《病原生物与免疫学》是一门重要的医学基础课,是紧密联系基础医学与临床医学的桥梁课程。病原生物学是学生在将来的工作中治疗、预防各种感染性疾病的重要知识基础,医学免疫学又是一门飞速发展、渗透到医学各个学科、具有广泛发展前景的重要课程。这些科目的设置、安排关系到护理学生专业知识的掌握程度[1]。同时让学生明确病原生物与免疫学在以岗位需求为导向的护理专业人才培养中的作用,对学生重视本门课程的学习起着重要的作用。     

Unpackaging synthetic biology: Identification of oversight policy problems and options

The emerging field of synthetic biology (SB) is just entering policy debates. Reports from non-governmental organizations, such as the ETC Group and the International Risk Governance Council, have recently been issued, but there have been few systematic analyses of the policy problems that we will likely face as this area develops. Biosecurity issues are the most defined; other societal oversight issues and implications have not been well explored. Although SB could assist in addressing pressing global challenges, such as sustainable and renewable energy, there are considerable societal concerns that accompany its development and applications. This article is designed to anticipate and prepare for these concerns by identifying policy problems associated with SB oversight, upstream of its development. Projected applications of SB are reviewed and a typology of them is developed. Key oversight policy problems are then identified based on historical experiences with other emerging technologies, such as nanotechnology and biotechnology. Problems associated with biosecurity, biosafety, intellectual property, and ethics are discussed in relation to the typology of SB applications to identify applications of the highest potential concern. Finally, policy options for SB oversight are considered, preventative to promotional. We propose that different categories of SB application may warrant different oversight regimes: there might not be an appropriate “one size fits all” approach. We stop short of making specific recommendations, but suggest that the typology, problems, and oversight options identified in this article be used as a starting point for deliberative, democratic decisionmaking processes that take into account a wide range of perspectives about risk, economic impact, scientific progress, and moral reasoning in the design of oversight systems.     

An Unusual Case of Predation: Dog Pack or Cougar Attack?

Injuries produced by animals are capable of leaving severe patterns and in some cases may result in the death of the attacked individual. Law enforcement authorities may come to erroneous conclusions about the source of the bites based on their awareness of animals present and similarities of the injuries to the untrained eye, with dreadful consequences. Expertise of a carnivore biologist and an odontologist that indentifies the particularities of bite marks may be useful for identifying the attacking species. We present the investigation of a fatal dog pack attack involving a 43‐year‐old man in Bell Ville (Argentina) where the evidence provided by a forensic dentist and a biologist was categorical for establishing the animal species involved. Because of the unusual characteristics of the wounds and the initial hypothesis made by local authorities of a cougar attack, habits and specific patterns of both dog pack and cougar predation on humans are discussed.     

Variation in nuclear DNA concentrations during urination

This study examined the cellular origin and concentration of nuclear DNA in human urine. Ten subjects provided two entire, first-morning voids: one as a single specimen and one as a consecutive series of samples. The serial samples were centrifuged, organically extracted, and quantified by slot-blot analysis. Total DNA concentrations ranged from 0.02 to 21.3 ng/mL for the males and 25.0 to 96.9 ng/mL for the females. The female samples were found to contain numerous vaginal epithelial cells. DNA was detected in all of the serial samples of nine subjects; however, the DNA concentrations varied considerably. With six subjects, the DNA concentration of the first serial sample was at least three times greater than that of the entire void. DNA was only detected in the first 21% of the void from one male subject. The results of this study have implications for the collection of urine samples.     

Fatty Acid Profiles for Differentiating Growth Medium Formulations Used to Culture Bacillus cereus T‐strain Spores

Microbial biomarkers that indicate aspects of an organism's growth conditions are important targets of forensic research. In this study, we examined fatty acid composition as a signature for the types of complex nutrients in the culturing medium. Bacillus cereus T‐strain spores were grown in medium formulations supplemented with one of the following: peptone (meat protein), tryptone (casein protein), soy protein, and brain–heart infusion. Cellular biomass was profiled with fatty acid methyl ester (FAME) analysis. Results showed peptone cultures produced spores enriched in straight‐chained lipids. Tryptone cultures produced spores enriched in branched‐odd lipids when compared with peptone, soy, and brain–heart formulations. The observed FAME variation was used to construct a set of discriminant functions that could help identify the nutrients in a culturing recipe for an unknown spore sample. Blinded classification tests were most successful for spores grown on media containing peptone and tryptone, showing 88% and 100% correct identification, respectively.