云南大麻DNA的提取及检测初步研究

目的探讨云南大麻DNA的提取及检测方法。方法运用改进的SDS微量法提取大麻总DNA,对所得DNA进行PCR检测。结果用所筛选到的大麻引物检测了云南大麻的DNA遗传标记特征,图谱清晰,结果稳定。结论本方法能有效提取并检测大麻DNA,为实现大麻的品种鉴定、遗传多态性研究及来源追踪提供有价值的科学依据。     

毓麟2号方对男性不育伴精索静脉曲张患者精液参数及精子DNA碎片指数的影响

目的 观察毓麟2号方对肾虚瘀阻型男性不育伴精索静脉曲张患者精液参数及精子DNA碎片指数(DNA-fragmetation index,DFI)的影响.方法 将118例肾虚瘀阻型男性不育伴精索静脉曲张患者随机分为治疗组和对照组,每组59例.治疗组给予毓麟2号方,对照组给予迈之灵片联合五子衍宗丸.比较两组患者临床综合疗效和...     

大白口蘑子实体的化学成分研究

目的 研究大白口蘑(Tricholoma giganteum Massee)子实体的化学成分。方法 大白口蘑子实体的乙酸乙酯部位经过硅胶、RP-18、Sephadex LH-20等多种材料进行分离纯化, 通过现代波谱技术进行结构鉴定。结果 分离鉴定了12个化合物,它们分别为：亚油酸甲酯（1）、亚油酸（2）、麦角甾-4, 6, 8 (14), 22-四烯-3-酮（3）、麦角甾-5, 7, 22-三烯-3β-醇（4）、过氧麦角甾醇（5）、麦角甾-7, 22-二烯-3β, 5α, 9α-三羟基-6酮（6）、麦角甾-7, 22-二烯-3β, 5α-二羟基-6酮（7）、麦角甾-7, 22-二烯-3β, 5α, 6α, 9α-四醇（8）、麦角甾-7, 22-二烯-3β, 5α, 6β, 9α-四醇（9）、麦角甾-7, 22-二烯-3β, 5α, 6β-三醇（10）、3β-O-glucopyranosyl-5α, 6β-dihydroxy-ergosta-7,22-diene（11）、脑苷脂D（12）。结论 化合物1-3、6-12均为首次从该种真菌中分离得到。     

利用GSS高通量测序技术分析不同生境下霍山石斛内生真菌群落的分布

目的 研究不同地域及不同生长环境下霍山石斛内生真菌群落的分布特征。方法 采用DNA分子标定技术确定不同霍山石斛样本的属种,利用GSS高通量测序技术分析霍山石斛样本内生真菌的种类。结果 供试的所有来源的霍山石斛样本均为Dendrobium huoshanense。从10个霍山石斛样本（编号LP1、LP2、LD1、LD2、LS1、LS2、HP1、HP2、JP1、JP2）中分别获得OTU数540、390、405、376、121、601、423、426、392、394个,通过分析每个OTU对应的物种分类信息,这些霍山石斛样本的内生真菌群落分布可归属至种水平,且分别包含内生真菌140、110、134、128、133、142、144、127、151、135种;样本LP1和LP2共有的OTU在物种水平上占84.22%,LD1和LD2共有的OTU在物种水平上占95.58%,LS1和LS2共有的OTU在物种水平上占94.52%,HP1和HP2共有的OTU在物种水平上占93.59%,JP1和JP2共有的OTU在物种水平上占94.05%。结论 不同地域及不同生长环境下霍山石斛（Dendrobium huoshanense）的内生真菌种类存在着差异性,相同地域及相同生长环境下霍山石斛（Dendrobium huoshanense）的内生真菌群落组成基本相同,霍山石斛（Dendrobium huoshanense）内生真菌的生长存在着地域专属性。     

Mitochondrial DNA Extraction from Burial Soil Samples at Incremental Distances: A Preliminary Study

Preservation variance of soil DNA is neglected in the literature, and exceptional cases exaggerate amplification capabilities. This study sought to amplify a short mitochondrial fragment (212 bp) specific to Sus scrofa domesticus from the soil surrounding decomposing pig remains from an open‐air locale. Samples collected above the body at incremental distances after 145 days of initial placement yielded pig DNA. A secondary sampling was collected in 2017, approximately 768 days after burial. Inhibition tests corroborated that pig DNA was no longer present in the soil resulting in a loss of original DNA between 145 and 768 days. The results provide evidence that genetic material leaches out radially from the source and DNA fragments longer than 200 bp do not persist in soil for a relatively short timeframe in western Montana. The conclusions support the collection of soil in crime scene investigation procedures within the first few months of decomposition.     

Familial DNA searching- an emerging forensic investigative tool

In recent years, jurisdictions across the United States have expressed a growing interest in aiding criminal investigations through the use of familial DNA searching (FDS)- a forensic technique to identify family members through DNA databases. The National Survey of CODIS Laboratories surveyed U.S. CODIS laboratories about their perceptions, policies, and practices related to FDS. In total, 103 crime labs completed the survey (77% response rate). Labs in 11 states reported using FDS, while labs in 24 states reported using a similar-but distinct- practice of partial matching. Although the majority of labs had positive perceptions about the ability of FDS to assist investigations, labs also reported a number of concerns and challenges with implementing FDS. Respondents reported using either practice a limited amount with modest numbers of convictions resulting from both FDS and partial matching. The article reports on varying practices related to official policies, training, eligibility, the software search, lineage testing, requirements for releasing information, and subsequent investigative work. Finally, the article discusses what can be learned from this survey, accompanying limitations, and implications for decision-makers considering using FDS.     

DNA typing from skeletal remains using GlobalFiler™ PCR amplification and Investigator® 24plex QS kits

Since the beginning of our work in 2003 our laboratory has focused exclusively on STR DNA from bone, a powerful tool in missing person cases. In cases such as mass disasters or missing persons, human remains are challenging to identify as they may be fragmented, burnt, recovered from water, degraded, and/or contain inhibitory substances. To address these challenges, this study has evaluated the performance of relatively new STR kits Investigator® 24plex QS kit (Qiagen) and GlobalFiler™ PCR Amplification kit (Thermo Fisher Scientific) by comparing it with current uses of the AmpFLSTR® Identifiler® Plus kit (Applied Biosystems) to obtain genetic information from skeletal remains. We analyzed 20 bone samples of skeletal remains from routine casework submitted for body identifications by law enforcement corresponding using Investigator® 24plex QS kit and GlobalFiler™ PCR Amplification kit, previously analysed AmpFLSTR® Identifiler® Plus kit (Thermo Fisher Scientific). The data indicates that the STR profiles obtained using the GlobalFiler™ and Investigator® 24plex QS kit for analysis of skeletal remains has shown results in an increased number of reportable genetic loci, and provide greater power of discrimination in comparison to the Identifiler® Plus Kit. Advanced extraction and purification techniques, together with more sensitive and robust new amplification kits allowed us to overcome the challenges associated with processing compromised skeletal remains and ultimately obtain full STR DNA profiles in 99% of the bones.     

Determination of DNA yield rates in six different skeletal elements in ancient bones

Current sampling strategy for laboratories typing bones for human identification include samples obtained from femur, tooth and temporal bone. Latest studies suggest that the small bones of the hands and feet were very similar or even better in DNA yield. These bones can be easily sampled with a disposable scalpel and thus reduce potential DNA contamination. The aim of our study was to determine the suitability of metatarsals, metacarpals and phalanges for genetic identification. 48 bone samples from 8 different skeletons (six from 18^th century and two from 3rd century) were obtained from 5 archaeological sites in Slovenia. In each skeleton, 6 different skeletal elements were sampled (temporal bone, molar, femur, metacarpal bone, metatarsal bone and proximal phalanx of the hand), and strict precautions followed to prevent contamination. Half of gram of bone powder was decalcified using full demineralization extraction method. The DNA was purified in a Biorobot EZ1 (Qiagen), DNA content determined with the PowerQuant kit (Promega), and autosomal STR typing performed with the Investigator ESSplex Plus kit (Qiagen). Up to 8.75 ng DNA/g of powder was obtained from samples analyzed. The highest yields were detected in temporal bone and the lowest in femur. The success rate of STR typing was evaluated according to the number of successfully typed loci and a strong correlation between the success rate of STR typing and the amount of extracted DNA was confirmed. For all eight skeletons full consensus genetic profiles were determined from skeletal elements analyzed. Our findings suggest it would be suitable to include metatarsal and metacarpal bones in sampling strategy for human identification although further research is needed to substantiate the findings of this study.     

How to avoid driving DNA caseworkers crazy: CaseSolver,an expert system to investigate complex crime scenes

DNA analyses can be used for both investigative (crime scene-focused), or evaluative (suspect-focused) reporting. Investigative, DNA-led exploration of serious crimes always involves the comparison of hundreds of biological samples submitted by the authorities for analysis. Crime stain comparisons include both evidence to evidence profiles and reference to evidence profiles. When many complex DNA results (mixtures, low template LT-DNA samples) are involved in the investigation of a crime, the manual comparison of DNA profiles is very time-consuming and prone to manual errors. In addition, if the person of interest is a minor contributor, the classical approach of performing searches of national DNA databases is problematic because it is realistically restricted to clear major contributors and the occurrence of masking and drop-out means that there will not be a definitive DNA profile to perform the search with.CaseSolver is an open source expert system that automates analysis of complex cases. It does this by three sequential steps: a) simple allele comparison b) likelihood ratio (LR) based on a qualitative model (forensim) c) LR based on a quantitative model (EuroForMix). The software generates a list of potential match candidates, ranked according to the LRs, which can be exported as a report. The software can also identify contributors from small or large databases (e.g., staff database or 1 mill. individuals). In addition, an informative graphical network plot is generated that easily identifies contributors in common to multiple stains. Here we describe recent improvements made to the software in version v1.5.0, made in response to user requirements during intensive casework usage.