Seong Hwan Park

Use of Cytochrome c Oxidase Subunit I (COI) Nucleotide Sequences for Identification of the Korean Luciliinae Fly Species (Diptera: Calliphoridae) in Forensic Investigations

Blowflies, especially species belonging to the subfamily Luciliinae, are the first insects to lay eggs on corpses in Korea. Fast and accurate species identification has been a key task for forensic entomologists. Because conventional morphologic identification methods have many limitations with respect to forensic practice, molecular methods have been proposed to identify fly species of forensic importance. To this end, the authors amplified and sequenced the full length of the cytochrome c oxidase subunit I (COI) gene of the Luciliinae fly species collected in Korea. The results showed the COI sequences are instrumental in identifying Luciliinae fly species. However, when compared with previously reported data, considerable inconsistencies were noted. Hemipyrellia ligurriens data in this study differed significantly from two of the five pre-existing data. Two closely related species, Lucilia illustris and Lucilia caesar, showed an overlap of COI haplotypes due to four European sequences. The results suggest that more individuals from various geographic regions and additive nuclear DNA markers should be analyzed, and morphologic identification keys must be reconfirmed to overcome these inconsistencies.

Transthoracic fine needle aspiration and core biopsy of pulmonary lesions. A study of 296 patients.

OBJECTIVE To retrospectively investigate and compare the usefulness of transthoracic fine needle aspiration (FNA), core biopsy and a combination of the two in the diagnosis of pulmonary lesions. STUDY DESIGN Two hundred ninety-six patients who had undergone FNA, core biopsy or both for lung lesions were divided into malignant and benign groups according to the final diagnoses, which were based on the cytologic and histopathologic findings combined with clinical features. In each group, the diagnostic usefulness of FNA, core biopsy and a combination of the two were evaluated by comparing the results of each with the final diagnoses. RESULTS In the malignant group, FNA was diagnostically helpful in 188 of 205 patients (91.7%) and core biopsy in 158 of 180 patients (87.8%). The combination of the two methods improved the result to 172 of 178 patients (96.6%). The sensitivities were 94.6%, 88.3% and 97.2%, respectively, for each result. In the benign group, 71.1% (64/90), 70.1% (47/67) and 74.2% (49/66) of cases received specific or nonspecific diagnoses by FNA, core biopsy and their combination, respectively. The rates of specific diagnoses were 20.1%, 21.0% and 31.8%, respectively. CONCLUSION The combination of FNA and core biopsy markedly improved the diagnostic yields in the malignant group and, to a lesser degree, also in the benign group.

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.

The Microevolution of V1r Vomeronasal Receptor Genes in Mice

Vomeronasal sensitivity is important for detecting intraspecific pheromonal cues as well as environmental odorants and is involved in mating, social interaction, and other daily activities of many vertebrates. Two large families of seven-transmembrane G-protein–coupled receptors, V1rs and V2rs, bind to various ligands to initiate vomeronasal signal transduction. Although the macroevolution of V1r and V2r genes has been well characterized throughout vertebrates, especially mammals, little is known about their microevolutionary patterns, which hampers a clear understanding of the evolutionary forces behind the rapid evolutionary turnover of V1r and V2r genes and the great diversity in receptor repertoire across species. Furthermore, the role of divergent vomeronasal perception in enhancing premating isolation and maintaining species identity has not been evaluated. Here we sequenced 44 V1r genes and 25 presumably neutral noncoding regions in 14 wild-caught mice belonging to Mus musculus and M. domesticus, two closely related species with strong yet incomplete reproductive isolation. We found that nucleotide changes in V1rs are generally under weak purifying selection and that only ∼5% of V1rs may have been subject to positive selection that promotes nonsynonymous substitutions. Consistent with the low functional constraints on V1rs, 18 of the 44 V1rs have null alleles segregating in one or both species. Together, our results demonstrate that, despite occasional actions of positive selection, the evolution of V1rs is in a large part shaped by purifying selection and random drift. These findings have broad implications for understanding the driving forces of rapid gene turnovers that are often observed in the evolution of large gene families.

Sequences of the cytochrome C oxidase subunit I (COI) gene are suitable for species identification of Korean Calliphorinae flies of forensic importance (Diptera: Calliphoridae).

Abstract:  Calliphorinae fly species are important indicators of the postmortem interval especially during early spring and late fall in Korea. Although nucleotide sequences of various Calliphorinae fly species are available, there has been no research on the cytochrome c oxidase subunit I (COI) nucleotide sequences of Korean Calliphorinae flies. Here, we report the full‐length sequences of the COI gene of four Calliphorinae fly species collected in Korea (five individuals of Calliphora vicina, five Calliphora lata, four Triceratopyga calliphoroides and three Aldrichina grahami). Each COI gene was amplified by polymerase chain reaction and directly sequenced and the resulting nucleotide sequences were aligned and analyzed by MEGA4 software. The results indicate that COI nucleotide sequences can be used to distinguish between these four species. Our phylogenetic result coincides with recent taxonomic views on the subfamily Calliphorinae in that the genera Aldrichina and Triceratopyga are nested within the genus Calliphora.

Using the Developmental Gene Bicoid to Identify Species of Forensically Important Blowflies (Diptera: Calliphoridae)

Identifying species of insects used to estimate postmortem interval (PMI) is a major subject in forensic entomology. Because forensic insect specimens are morphologically uniform and are obtained at various developmental stages, DNA markers are greatly needed. To develop new autosomal DNA markers to identify species, partial genomic sequences of the bicoid (bcd) genes, containing the homeobox and its flanking sequences, from 12 blowfly species (Aldrichina grahami, Calliphora vicina, Calliphora lata, Triceratopyga calliphoroides, Chrysomya megacephala, Chrysomya pinguis, Phormia regina, Lucilia ampullacea, Lucilia caesar, Lucilia illustris, Hemipyrellia ligurriens and Lucilia sericata; Calliphoridae: Diptera) were determined and analyzed. This study first sequenced the ten blowfly species other than C. vicina and L. sericata. Based on the bcd sequences of these 12 blowfly species, a phylogenetic tree was constructed that discriminates the subfamilies of Calliphoridae (Luciliinae, Chrysomyinae, and Calliphorinae) and most blowfly species. Even partial genomic sequences of about 500 bp can distinguish most blowfly species. The short intron 2 and coding sequences downstream of the bcd homeobox in exon 3 could be utilized to develop DNA markers for forensic applications. These gene sequences are important in the evolution of insect developmental biology and are potentially useful for identifying insect species in forensic science.

Fine needle aspiration cytology of primary pulmonary paraganglioma: A case report

BACKGROUND Primary pulmonary paragangliomas are rare tumors. To our knowledge, there is no prior report on fine needle aspiration cytology (FNAC) in pulmonary paraganglioma. CASE A 34-year-old man presented with an incidentally found solitary pulmonary mass. FNAC showed papillarylike clusters of epithelioid cells with round to oval nuclei, evenly dispersed chromatin, micronucleoli and occasional anisonucleosis. These cytologic features were suggestive of a sclerosing hemangioma or bronchioloalveolar carcinoma. A right lower lobectomy revealed a primary pulmonary paraganglioma. CONCLUSION The possibility of pulmonary paraganglioma should be considered in the differential diagnosis of FNAC showing pseudopapillary clusters of epithelioid cells.

Discolouration of the brain as the only remarkable autopsy finding in hydrogen sulphide poisoning

Hydrogen sulphide (H2S), an extremely noxious gas that smells like rotten eggs [1], is generated from natural sources, industrial factories, sewage systems and putrefying organic materials [2,3]. Fatal H2S poisoning results in both nonspecific changes, such as pulmonary oedema and congestion [4,5], and greenish discolouration of the internal organs, especially of the brain [6–8]. However, despite its reputation, this ‘classic’ discolouration is extremely rare [4], and the greenish discolouration of the internal organs have only been identified in three reports [6,7,9]. Here, the authors report a fatal case of H2S poisoning, where the only remarkable autopsy finding was greenish discolouration of the brain.

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.

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.