The effects of chemical and heat maceration techniques on the recovery of nuclear and mitochondrial DNA from bone

Forensic anthropologists use a number of maceration techniques to facilitate skeletal analysis of personal identity and trauma, but they may unwittingly eliminate valuable DNA evidence in the process. This study evaluated the effect of 10 maceration methods on gross bone structure and the preservation of DNA in ribs of 12 pigs (Sus scrofa). A scoring system was applied to evaluate the ease of maceration and resulting bone quality while DNA purity was quantified by optical densitometry analysis, followed by polymerase chain reaction (PCR) amplification of three mitochondrial and three nuclear loci. The results demonstrated that while mitochondrial DNA could be amplified for all experiments, cleaning treatments using bleach, hydrogen peroxide, ethylenediaminetetraacetic acid/papain, room temperature water and detergent/sodium carbonate followed by degreasing had low DNA concentrations and failed to generate nuclear PCR products. In general, treatments performed at high temperatures (90 degrees C or above) for short durations performed best. This study shows that traditionally "conservative" maceration techniques are not necessarily the best methods to yield DNA from skeletal tissue.     

Identification of a novel polymorphism in the X-chromosome region homologous to the DYS456 locus

During an extensive multipopulation study with Y-short tandem repeat (STR) loci, amplified using the AmpFlSTR Yfiler PCR amplification kit, amplification of a 71 bp fragment was observed in 2.32% of the male samples analyzed (N = 3141). By direct sequencing of this fragment, it was determined that the primer binding sequences were identical to those of the DYS456 locus. A T to G single-nucleotide polymorphism (SNP) enabled amplification of the 71 bp fragment. The SNP is located within an X-Y homologous region at Xq21.31 and was observed with the highest frequency within the African American and Sub-Saharan African populations in our study. Presence of SNP on the X chromosome did not interfere with the reliability of typing the DYS456 locus and the other Y-STR loci typeable using the AmpFlSTR Yfiler PCR amplification kit. Full profiles in a mixture of male:female at 1:4000 were obtained using the current configuration of the AmpFlSTR Yfiler kit even in the presence of female DNA containing the G variant.     

Sudden death from tubercular myocarditis

Tuberculous myocarditis is a rare finding. We present the case of a 33-year-old woman who was in good health and who died suddenly at home. Autopsy and histopathologic examinations revealed granulamatous lesions in the myocardium, lungs, lymph nodes, liver, and spleen. No fast acid bacilli were demonstrated on histological examination. The presence of a Mycobacterium tuberculosis DNA complex was identified using a polymerase chain reaction (PCR) on formalin-fixed paraffin-embedded histological samples. An HIV test carried out on the blood obtained during the autopsy was negative according to the DNA amplification technique (PCR) and enzyme-linked immunosorbent assay serological test. We hypothesize that the mechanism of death was severe ventricular arrhythmia due to granulomatous proliferation in the structures of the interventricular septum.     

Local Value Chain Development in Vietnam: Motorcycles,Technical Learning and Rents Management

This article analyses how foreign direct investment drives technological upgrading in the motorcycle industry in Vietnam. Using the analytical framework of rent management, the article evaluates the rent management mechanisms that provided the incentives and pressures for domestic firms to develop a local value chain by participating in the foreign supply network. This article offers a case study analysis of two periods: 1995–2000 and 2000–05. Two case studies examine the exchanges between lead firms and their suppliers; between multinational corporations and local firms; and among the state, private and foreign firms in the context of the value chain for motorcycle production. The analyses suggest that industrial upgrading has been predominantly driven by foreign direct investment starting in the early 2000s. In addition, market competition among Japanese and Chinese lead firms led to significant technical learning for domestic firms through collaboration with foreign firms despite the government’s failure to effectively monitor rents or implement industrial policies.     

颜色的文化蕴含

人们辨别颜色的视觉器官可以根据颜色的色彩、亮度和浓度把不同的颜色区分开来。实际生活经验的积累决定了颜色词汇的命名。不同文化背景的人有不同的颜色基本词 ;对同一颜色的反应和联想也不尽相同。颜色因特定文化环境文化习俗而具有特定的文化象征意义     

黔中经济区现代产业链分析

＂系统性竞合＂是现代区域竞合的重要特征,在发达国家再工业化、现代产业融合和国家加快经济发展方式转变的三大历史机遇面前,应该准确认识黔中经济区产业链的现状。构建黔中产业链,必须以制度整合与创新引导产业链整合与创新,建立起培养、吸引、用好产业发展需要人才的长效机制,坚持＂多产业链模式＂复合演进,打造大产业链的思路。准确认识区内产业链的核心价值环节,按照产业链本身的要求来承接转移产业,加大对核心链环的资源配置力度,整合区域产业链。     

Polymerase Resistance to Polymerase Chain Reaction Inhibitors in Bone*

Abstract: Amplification of DNA from aged or degraded skeletal remains can be a challenging task, in part due to naturally occurring inhibitors of the polymerase chain reaction. PCR inhibitors may act by inactivating a polymerase itself, or compete with or bind other reaction components, although various polymerases may be differentially susceptible to such insult. In this study, ten thermostable polymerases from six bacterial species were examined for their ability to amplify DNA in the presence of bone‐derived or individual PCR inhibitors. Two polymerases, one from Thermus aquaticus and one from Thermus thermophilus, showed lower susceptibility to inhibition from bone, while polymerases from Thermus flavus were highly susceptible. Addition of bovine serum albumin improved the activity of most of the enzymes. Taken together, the results indicate that thermostable DNA polymerases have different susceptibility to bone‐derived PCR inhibitors, and that those most often used in forensic laboratories may not be optimal when working with DNA from skeletal remains.