激光捕获显微切割技术用于分离混合斑中精子细胞

目的 评估激光捕获显微切割(laser capture microdissection.LCM)技术在分离混合斑中少量精子细胞的应用价值.方法 配制不同比例的精液-阴道上皮细胞混合液.分别用差异裂解法和LCM法分离精子细胞,用磁珠法提取精子细胞DNA,并用IdentifilerTM试剂盒进行STR基因型检测.结果 LC...     

尼龙膜套管分离技术对混合斑中精子细胞DNA的提取

目的建立新型的混合斑中精子细胞分离的方法,并评价其应用价值。方法收集性侵案件中的40份混合斑检材,分别采用常规差异裂解法和尼龙膜套管分离技术进行精子细胞分离,使用硅膜试剂盒(Forensic DNA Extraction Kit for Soft Tissues)提取精子细胞DNA,Amp FlSTR~ Identifiler~ Plus PCR扩增试剂盒进行PCR扩增,3500x L基因分析仪进行电泳检测,并对两种分离方法的结果进行对比。结果 40份混合斑检材中,采用尼龙膜套管分离技术的检材仅3份有女性成分微弱残留,余均获得了完整的单一男性分型。而采用常规差异裂解法分离的检材中,有25份完全未检出男性精子细胞STR分型,15份检出男性精子细胞STR分型(7份不完整男性精子细胞STR分型,6份有女性成分残留,2份单一的男性精子细胞STR分型)。结论本研究建立的尼龙膜套管分离技术适用于混合斑中精子细胞的分离,特别是对含有大量女性细胞而精子细胞较少的检材提取效果明显,整个提取实验成本低廉、快速简便。     

DNase-Ⅰ纯化结合碱性裂解法提取混合斑精子DNA

目的研究脱氧核糖核酸酶I(DNase-I)纯化结合碱性裂解法提取混合斑精子DNA的方法在法医学中的应用。方法收集79份性犯罪案件混合斑检材,分别用DNase-I纯化结合碱性裂解法和差异裂解法提取精子DNA,采用STR荧光标记复合扩增体系进行16个STR基因座分型,并比较检验结果。结果应用DNase-I纯化结合碱性裂解法提取精子DNA,64例检材分型成功;应用差异裂解法提取精子DNA,57例检材分型成功;两种方法比较结果存在显著性差异(P=0.039),DNase-1纯化结合碱性裂解法提取精子DNA的STR分型成功率更高,成本低廉。结论DNase-I纯化结合碱性裂解法提取混合斑精子DNA可提高检验成功率,操作简便,快速,易于自动化,适于法医学个体识别鉴定。     

DNase-I纯化结合碱性裂解法提取混合斑精子DNA

目的研究脱氧核糖核酸酶I(DNase-I)纯化结合碱性裂解法提取混合斑精子DNA的方法在法医学中的应用。方法收集79份性犯罪案件混合斑检材,分别用DNase-I纯化结合碱性裂解法和差异裂解法提取精子DNA,采用STR荧光标记复合扩增体系进行16个STR基因座分型,并比较检验结果。结果应用DNase-I纯化结合碱性裂解法提取精子DNA,64例检材分型成功;应用差异裂解法提取精子DNA,57例检材分型成功;两种方法比较结果存在显著性差异(P=0.039),DNase-1纯化结合碱性裂解法提取精子DNA的STR分型成功率更高,成本低廉。结论DNase-I纯化结合碱性裂解法提取混合斑精子DNA可提高检验成功率,操作简便,快速,易于自动化,适于法医学个体识别鉴定。     

改良差异裂解法结合硅珠法提取混合斑精子DNA

目的采用改良差异裂解法结合硅珠法提取混合斑中精子DNA,并评价其应用价值。方法收集52例经常规差异裂解法检验含有女性分型的混合斑检材,采用改良差异裂解法结合硅珠法提取精子细胞DNA,IdentifilerTM试剂盒进行PCR扩增检验。并将常规差异裂解法结果作为对照。结果52例混合斑检材中,采用改良差异裂解法结合硅珠法检出单一男性精子成分有38例,男性分型检出率达到98．08％。结论改良差异裂解法结合硅珠法适合提取混合斑中精子DNA。     

3种分离提取混合斑精子DNA的方法比较

性犯罪案件中最常见的生物学检材为精液与阴道分泌液混合斑,其精子DNA的提取通常情况下采用常规的差异裂解细胞法结合酚、氯仿抽提[1],但由于检材条件各不相同,有些混合斑中精子细胞极少,核酸得率和纯度较低,有检测失败的可能或致使精子STR分型困难[2]。文献曾报道过多种改良方法[3,4],但其成功与否很大程度上受到检验人员的经验、水平等主观因素以及检材的具体条件影响。本文作者应用差异裂解法、Phase lock GelTM法[5]和D ifferexTM法[6]对三组不同条件的混合斑样品分离提取精子DNA,使用Powerplex16TM试剂盒分型,对3种方法进行比…     

应用免疫磁珠分离混合斑中精子

目的探讨应用免疫磁珠法分离精子-上皮细胞混合液中精子的可行性。方法制备不同比例的精子-上皮细胞混合液各15例,分别应用免疫磁珠法及差异裂解法提取精子,经PCR扩增进行DNA-STR分型,比较两者的差异。结果免疫磁珠可以特异性捕获精子,对精子个数为500～2 000/mL的混合斑STR分型成功率(正确分型13个以上,RFU200)为93.33%,差异裂解法为46.67%,两种方法存在明显差异(P0.05)。结论免疫磁珠可有效分离精子和混合斑中其他成分,在精子个数低于2 000个/mL检材中优于差异裂解法。     

人体接触检材前处理方式对磁珠法提取DNA效果的影响

目的比较3种常见的接触检材前处理方式对磁珠法提取DNA效果的影响。方法收集烟蒂、牙刷、纱线手套各10份;分别采用95℃、70℃直接裂解和TNE、SDS、PK预消化方式进行前处理,再用磁珠法提取纯化DNA,并进行DNA定量,统计提取的接触DNA量和IPC CT值;同时用Sinofiler复合扩增系统进行STR分型检测。结果 3种方法前处理后用磁珠提取的DNA纯度均较高I,PC CT值在26.63～27.19之间。用预消化法获得的DNA量高于裂解法,而95℃裂解与70℃裂解方法提取的DNA量无显著性差异。STR扩增检测结果亦表明,采用预消化法处理的样品STR分型成功率高于裂解法9,5℃与70℃裂解方法处理的样品STR分型成功率无显著性差异。结论人体接触检材采用预消化磁珠法提取DNA,有助于提高STR检验成功率。     

精子富集柱分离技术的研究

目的在传统差异裂解法基础上,研究建立新的混合斑检材中精子分离技术。方法根据精细胞的结构特点,研制精子富集柱。取混合斑检材经第一步消化后的混合液,加入精子富集柱中离心,使DNA等小分子物质透过,而精细胞被特异性黏附和拦截在富集层中。采用本文技术和常规裂解方法对12份混合斑检材中精子进行分离,分离后精子DNA采用Identifiler试剂盒进行PCR扩增和电泳检测。结果混合斑检材经精子富集柱分离后均获得单一男性精子的STR分型结果,而12份检材用常规裂解方法分离,其中有6份检材女性成分去除不完全或未能检出精子STR基因型。结论本研究建立的精子富集柱分离技术适用于常见混合斑检材中精子的分离,特别适合对含有大量女性混合物而精子量较少检材的分离提取。     

混合斑中精子细胞分离及其DNA制备方法

目的尝试建立一种检测混合斑中精子细胞的方法。方法使用显微操作法捕获精子细胞,全基因组扩增(多重置换扩增)精子细胞DNA。结果对10管精斑检材的全基因组扩增,获得了高产、保真的产物。使用50μL体系对20个精子细胞直接进行全基因组扩增,省去了对起始模板的纯化过程,DNA扩增倍数达30000倍以上,片段长度大多在15 kb以上,其STRs复合扩增分型结果有可参照性。结论显微操作法可以有效捕获精子细胞,排除干扰,多重置换扩增可以提供足够量的产物用于法医DNA分析,该方法具有可行性。     

Alternative direct-to-amplification cell lysis techniques for forensically relevant non-sperm cells

While efforts have been made to reduce the pervasive backlog of sexual assault evidence collection kits, the actual laboratory process remains very time-consuming due to the requirement of a differential lysis step before DNA purification, as well as intricate mixture analysis towards the end of the DNA workflow. Recently, an alternative, direct-to-amplification sperm lysis method (using 1 M NaOH) was identified. However, a direct cell lysis method for non-sperm cells has not been identified yet. Thus, the primary objective of this work was to find an alternative method that is quick, inexpensive, and does not require multiple purification steps for the lysis of non-sperm cells in sexual assault samples. In this study, vaginal swab samples were lysed with the control method, prepGEM™, as well as six alternative reagents: alkaline buffer with 25–200 mM NaOH, high-salt stain extraction buffer, modified radioimmunoprecipitation assay (RIPA) buffer, mammalian protein extraction reagent (M-PER™), digitonin buffer, and urea/thiourea buffer. Quantification using Quantifiler® Trio of vaginal and semen lysates revealed that the alkaline (25 mM NaOH) and M-PER™ methods were efficient for the lysis of vaginal epithelial cells without substantial sperm cell lysis. Following quantification, analysis of STR profiles from vaginal lysates revealed that the M-PER™ method showed promising results across all metrics examined, including the percentage of detected STR alleles, mean peak heights, peak height ratio, and interlocus balance. Thus, this method was recommended as an alternative to the traditional differential lysis method for non-sperm cells given its ability to produce amplification-ready lysates without any DNA purification step.     

龙胆紫染色法在显微捕获单细胞分离技术中的应用

目的建立用于显微捕获单细胞技术的龙胆紫染色法并评价其应用效果。方法制作20枚口腔拭子脱落细包悬液,配制0．05g／mL龙胆紫染液。取100μL口腔细胞悬液加入0．15、0．25、0．5、1．0、2．0μL染色液,考察最佳染色浓度;争别染色5、10、30、60min,考察最佳染色时间;用最佳条件染色后抓捕3个细胞,采用联合LV-PCR技术扩增并进行DNA分驯佥测,进行重复试验20次,并对同一检材未经染色的抓捕细胞进行检测,用于比对STR分型成功率。将龙胆紫染色法用于案例检材的口腔上皮细胞分离检验。结果1001μL细胞悬液加入0．5止0．05g／mL龙胆紫染液,染色5min,胞核呈紫工色,与胞浆对比明显;染色时间延长不影响染色效果及细胞分离检验结果。优化后的龙胆紫染色法对低体积扩增无归显抑制（P〉0．05）。应用此染色法于案例检材,胞核标识清晰,STR分型结果达同一认定标准。结论龙胆紫染色法刚于细胞核的发现,有助于提高显微捕获单细胞技术的检测效能。     

Droplet-based optical trapping for cell separation in mock forensic samples

Optical tweezers have a wide range of uses for mechanical manipulation of objects in the microscopic range. This includes both living and static cells in a variety of biomedical and research applications. Single-focus optical tweezers, formed by focusing a laser beam through a high numerical aperture immersion objective, create a significant force, which enables controlled transport of a variety of different cell types and morphologies in three dimensions. Optical tweezers have been previously reported to capture and separate spermatozoa from a reconstituted simulated postcoital sample. We report herein the development of a simplified, more efficient cell transfer protocol that can separate and isolate both spermatozoa as well as leukocytes, with similar efficiencies as those previously reported. The new cell transfer method was used to separate sperm cells from a reconstituted mixture of spermatozoa and vaginal epithelial cells, with complete STR profiles developed from 50 cells with little evidence of contribution from the female contributor to the mixture. This modified protocol was then used to separate 21 samples of enriched leukocytes, with trapped cells ranging from 5 to 22 cells. Complete STR profiles were developed from as few as 10 leukocytes. Thus, with minimal sample preparation and a short trapping time, this method has the potential to provide an alternative to traditional differential extraction methods for separation of sperm:nonsperm mixtures while also providing versatility for separation of cells with differing morphologies.     

精子细胞定向捕获与分离技术初步研究

目的探索并研究精子细胞定向捕获与分离技术,初步建立精子细胞特异性分离与DNA提取的方法与试剂体系。方法通过特异性定向捕获复合体（精子特异性抗体一磁性纳米微球）的制备,在一定的试剂体系环境下,实现精子细胞的定向捕获与分离。结果能够实现精子细胞的定向富集与分离,通过后续的提取过程,获得了高质量的DNA,并获得了相应的完整STR分型结果。     

PALM结合低体积扩增技术在混合斑检验中的应用

目的PALM系统联合应用低体积扩增技术,建立一种提取混合斑中精子DNA的分型方法。方法利用PALM切割捕获理想检材的精子细胞,将捕获的细胞直接放置到低体积扩增玻片的反应位点上,裂解细胞之后进行PCR扩增。结果20个精子细胞8次分型中,7次分型结果完全正确。10个精子细胞8次分型中,4次分型结果完全正确。1个精子细胞8次分型中,出现位点的基因座均在10个以上。将该方法应用于两例实际案例的混合斑检材,取得了满意效果。结论联合运用PALM系统和低体积扩增技术对混合斑检材中的精子细胞检验具有重要意义。