Molecular identification of necrophagous muscidae and sarcophagidae fly species collected in Korea by mitochondrial cytochrome C oxidase subunit I nucleotide sequences.

Identification of insect species is an important task in forensic entomology. For more convenient species identification, the nucleotide sequences of cytochrome c oxidase subunit I (COI) gene have been widely utilized. We analyzed full-length COI nucleotide sequences of 10 Muscidae and 6 Sarcophagidae fly species collected in Korea. After DNA extraction from collected flies, PCR amplification and automatic sequencing of the whole COI sequence were performed. Obtained sequences were analyzed for a phylogenetic tree and a distance matrix. Our data showed very low intraspecific sequence distances and species-level monophylies. However, sequence comparison with previously reported sequences revealed a few inconsistencies or paraphylies requiring further investigation. To the best of our knowledge, this study is the first report of COI nucleotide sequences from Hydrotaea occulta, Muscina angustifrons, Muscina pascuorum, Ophyra leucostoma, Sarcophaga haemorrhoidalis, Sarcophaga harpax, and Phaonia aureola.

Molecular identification of forensically important calliphoridae and sarcophagidae species using ITS2 nucleotide sequences.

The application of insect evidence to forensic investigations is mainly based on the estimation of postmortem interval and the identification of insect species from samples that are collected from the crime scene. Due to the limited number of expert taxonomists, species identification is one of the major barriers for crime scene investigators to utilize forensic entomology. Therefore, the molecular identification of species, using mitochondrial cytochrome c oxidase subunit I (COI) gene, has been suggested as an alternative strategy. However, in some cases, these maternally inherited markers cause confusion; hence, nuclear DNA markers such as ITS2 are also required as supporting tools. Eleven Calliphoridae and 5 Sarcophagidae fly species collected from Korea were utilized for PCR amplification and nucleotide sequencing of ITS2 locus. Species Identifier software was used for sequence analysis and comparison. The results demonstrated that 11 Korean Calliphoridae and 5 Korean Sarcophagidae fly species could be distinguished using ITS2 nucleotide sequences. In particular, the sister species, Lucilia illustris and Lucilia caesar were also distinguished, despite the very low level of interspecific diversity. However, when compared with previously reported ITS2 nucleotide sequences, several identification failures were noted. This is the first study that widely analyzed nucleotide sequences of the ITS2 locus from Calliphoridae and Sarcophagidae fly species collected in Korea.

Investigation of bleeding focus in the intracranial vertebral artery with the use of posterior neck dissection method in traumatic basal subarachnoid hemorrhage.

Traumatic basal subarachnoid hemorrhage caused by minor blunt trauma to the head or neck can lead to rapid collapse and death. The vertebral arteries are the vessels most commonly involved in such cases, but it is very difficult to find the bleeding focus in the vertebral arteries in routine autopsy because of the location of these vessels. Using the posterior neck dissection method, which is relatively easy and avoids artificial damage to the intracranial portion of the vertebral arteries, authors have identified tear sites in the intracranial artery in four out of five consecutive traumatic basal subarachnoid hemorrhage cases. In this report we show that this new method is useful for cases of traumatic basal subarachnoid hemorrhage.

The First Survey of Forensically Important Entomofauna Collected from Medicolegal Autopsies in South Korea.

Forensic entomology applies insect evidence to legal problems such as the estimation of minimum postmortem interval (mPMI). For this purpose, knowledge of the insect fauna that are attracted to human cadavers in each geographic region is a prerequisite. Despite many studies investigating the insect fauna attracted to meat, there has been no survey of the entomofauna on human cadavers in the East Asian temperate climate zone, particularly in Korea. Therefore, this study reports the entomofauna collected from medicolegal autopsies in northeastern Seoul and its suburbs. Insect samples were collected from 35 medicolegal autopsies in 2010, 2011, and 2013. Molecular and morphological methods were utilized for taxonomic identification. Among 1398 individual samples belonging to 3 orders, 13 families, 18 genera, and 32 species, the dominant family and species were Calliphoridae and Lucilia sericata, respectively. Despite its limited scale, this study provides a snapshot of the general entomofauna that are attracted to human cadavers in this region.

Postmortem mRNA expression patterns in left ventricular myocardial tissues and their implications for forensic diagnosis of sudden cardiac death.

Sudden cardiac death (SCD), which is primarily caused by lethal heart disorders resulting in structural and arrhythmogenic abnormalities, is one of the prevalent modes of death in most developed countries. Myocardial ischemia, mainly due to coronary artery disease, is the most common type of heart disease leading to SCD. However, postmortem diagnosis of SCD is frequently complicated by obscure histological evidence. Here, we show that certain mRNA species, namely those encoding hemoglobin A1/2 and B (Hba1/2 and Hbb, respectively) as well as pyruvate dehydrogenase kinase 4 (Pdk4), exhibit distinct postmortem expression patterns in the left ventricular free wall of SCD subjects when compared with their expression patterns in the corresponding tissues from control subjects with non-cardiac causes of death. Hba1/2 and Hbb mRNA expression levels were higher in ischemic SCD cases with acute myocardial infarction or ischemic heart disease without recent infarction, and even in cardiac death subjects without apparent pathological signs of heart injuries, than control subjects. By contrast, Pdk4 mRNA was expressed at lower levels in SCD subjects. In conclusion, we found that altered myocardial Hba1/2, Hbb, and Pdk4 mRNA expression patterns can be employed as molecular signatures of fatal cardiac dysfunction to forensically implicate SCD as the primary cause of death.

Quantitative analyses of postmortem heat shock protein mRNA profiles in the occipital lobes of human cerebral cortices: implications in cause of death.

Quantitative RNA analyses of autopsy materials to diagnose the cause and mechanism of death are challenging tasks in the field of forensic molecular pathology. Alterations in mRNA profiles can be induced by cellular stress responses during supravital reactions as well as by lethal insults at the time of death. Here, we demonstrate that several gene transcripts encoding heat shock proteins (HSPs), a gene family primarily responsible for cellular stress responses, can be differentially expressed in the occipital region of postmortem human cerebral cortices with regard to the cause of death. HSPA2 mRNA levels were higher in subjects who died due to mechanical asphyxiation (ASP), compared with those who died by traumatic injury (TI). By contrast, HSPA7 and A13 gene transcripts were much higher in the TI group than in the ASP and sudden cardiac death (SCD) groups. More importantly, relative abundances between such HSP mRNA species exhibit a stronger correlation to, and thus provide more discriminative information on, the death process than does routine normalization to a housekeeping gene. Therefore, the present study proposes alterations in HSP mRNA composition in the occipital lobe as potential forensic biological markers, which may implicate the cause and process of death.