• YAKHAK HOEJI
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• v.54 no.1
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• pp.67-74
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• 2010

Some of the benzopyrene (BP)-DNA adduct are known to build intercalated motif between flanking base pairs in damaged DNA depending on the structural condition. The size of benzopyrene itself is definitely not comparable with any of the DNA bases and thus the question whether the lesion of some base pair by insertion of benzopyrene can happen with or without a dramatic distortion of the helical structure is a highly interesting theme. In this work we used a molecular dynamics simulation based on the theory of molecular mechanics. The specific consequences about the structural properties of the intercalated structures and benzopyrene motif in minor groove of the double helix are deduced after 5 ns simulation time.

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.48-55
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• 2001

When an elongating RNA polymerase encounters DNA damage on the template strand of a transcribed gene it can either be arrested by or be transcribed through the lesion. Lesions that arrest RNA polymerases are thought to be subject to transcription-coupled repair, whereas that damage that is bypassed can cause miscoding, resulting in mutations in the transcript (transcriptional mutagenesis). We have developed a technique using a plasmid-based luciferase reporter assay to determine the extent to which a particular type of DNA base modification is capable of causing transcriptional mutagenesis in vivo. The system uses Escherichia coli strains with different DNA repair backgrounds and is designed to detect phenotypic changes caused by transcriptional mutageneis under nongrowth conditions. In addition, this method is capable of indicating the extent to which a particular DNA repair enzyme (or pathway) suppresses the occurrence of transcriptional mutagenesis. Thus, this technique provides a tool with which the effects of various genes on non-replication-dependent pathways resulting in the generation of mutant proteins can be gauged.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1993.05a
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• pp.89-89
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• 1993

The laryngeal epithelial cell kinetics of 26 laryngeal lesions(invasive squamous cell carcinoma 14, epithelial hyperplasia 5, laryngeal nodule 7) were studied by immunehistochemical analysis with the monoclonal antibody Ki-67, which reacts with nuclear antigen in proliferating cells using paraffin embedded tissue. For DNA analysis, touch implint with fresh biopsy specimens were stained with feulgen and analyzed by image analyzer in 22 cases. 1) The proportion of Ki-67-positive cells were 32.65$\pm$ 11.59% in invasive squamous cell ca, 20.14$\pm$3.38% in epithelial hyperplasia lesion and 11.66$\pm$3.02% in laryngeal nodule. 2) DNA aneuploidy was found in 7 cases of 10(70%) invasive squamous cell carcinomas, 2 cases of 5(40%) epithelial hyperplasia lesions and all cases of laryngeal 3) Proliferation index(S phase+G2/M phase) show 23.42$\pm$11.33% in squamous cell carcinoma, 13.09$\pm$ 10.90% in epithelial hyperplasia lesion and 4.50$\pm$1.19% in laryngeal nodule. As the results, measuring the DNA content from touch imprint method together positivity of Ki-67 antibody from the microtissue during the laryngeal microscopic surgery, cell kinetics can be assessed as an effort of deciding the prognosis and provide a key to the management of precancerous lesions.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.91-98
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• 2009

Infectious bursal disease (IBD) caused by the infectious bursal disease virus (IBDV) has an important economic impact on the poultry industry worldwide. This study examined the adjuvant effects of a plasmid encoding chicken interleukin-6 (pcDNA-ChIL-6) and levamisole (LMS) on in ovo prime-boost vaccination using a genetic vaccine (pcDNA-VP243) to prime in chicken followed by a killed-vaccine boost. A pcDNA-VP243 was injected into the amniotic sac alone or in combination with a pcDNA-ChIL-6 or LMS at embryonation day 18, followed by an intramuscular injection of killed IBD vaccine at 1 week of age. The chicken were orally challenged with very virulent IBDV (vvIBDV) strain at 3 weeks of age and observed for 10 days. No mortality was observed in the groups that received the pcDNA-VP243 alone and pcDNA-VP243 plus pcDNA-ChIL-6 or LMS compared to 100% mortality in unvaccinated challenge control group. However, as determined by bursal damage (the presence of IBDV RNA, B/B ratio, and lesion score), a pcDNA-VP243 alone group was superior to pcDNA-VP243 plus pcDNA-ChIL-6 or LMS groups in the protection against post-challenge. These findings suggest that in ovo priming with genetic vaccine and boosting with killed vaccine is an effective strategy for protecting chicken against vvIBDV and the addition of pcDNA-ChIL-6 or LMS did not enhance protective immunity.

• Environmental Mutagens and Carcinogens
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• v.23 no.3
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• pp.99-102
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• 2003

IARC classified areca quid as a human carcinogen. Areca quid chewed in Taiwan includes Piper betle inflorescence, which contains high concentrations of safrole (15 mg/fresh weight). Safrole is a documented rodent hepatocarcinogen, and chewing areca quid may contribute to human exposure (420 $\mu$m in saliva). The carcinogenicity of safrole is mediated through 1'-hydroxysafrole formation, followed by sulfonation to an unstable sulfate that reacts to form DNA adducts. Using human liver microsomes and Escherichia coli membranes expressing bicistronic human P450s, CYP2E1 and CYP2C9 were identified as the main P450s involved in the activation of safrole. We have demonstrated the presence of stable safrole-dGMP adducts in human oral tissues following areca quid chewing using $^{32}$ P-postlabeling and HPLC mass spectrometry methods. By studying 88 subjects with a known AQ chewing history and 161 matched controls, we have demonstrated that the presence of safrole-DNA adducts in peripheral blood cells was correlated to AQ chewing, and CYP2E1 seemed to play an important role in the modulation of safrole-DNA adduct formation. We have also shown that safrole can form stable safrole-DNA adducts as well as oxidative damages in rodent liver. However, the stable safrole-DNA adducts may represent a more significant initial lesion as compared to the rapidly repaired safrole-induced 8-hydroxy-2'-deoxyguanosine. This oxidative DNA damage is mediated through the formation of hydoryxchavicol, the major safrole metabolite in human urine. Hydroxychavicol may have gone through two-electron oxidation to the o-quinone; then via one-electron reduction to semiquinone radicals to generate oxidative DNA damage. However, these reactive metabolites can be efficiently conjugated by GSH. These data suggest that safrole may contribute to the initiation of oral carcinogenesis through safrole-DNA adduct and not oxidative DNA damage. In addition, CYP2E1 may modulate this adduct formation.

• The Plant Pathology Journal
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• v.38 no.6
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• pp.679-684
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• 2022

Rice blast is one of the most destructive diseases of rice worldwide, and the causative agent is the filamentous ascomycete Magnaporthe oryzae. With the successful cloning of more and more avirulence genes from M. oryzae, the direct extraction of M. oryzae genomic DNA from infected rice tissue would be useful alternative for rapid monitoring of changes of avirulence genes without isolation and cultivation of the pathogen. In this study, a fast, low-cost and reliable method for DNA preparation of M. oryzae from a small piece of infected single rice leaf or neck lesion was established. This single step method only required 10 min for DNA preparation and conventional chemical reagents commonly found in the laboratory. The AvrPik and AvrPi9 genes were successfully amplified with the prepared DNA. The expected DNA fragments from 570 bp to 1,139 bp could be amplified even three months after DNA preparation. This method was also suitable for DNA preparation from M. oryzae strains stored on the filter paper. All together these results indicate that the DNA preparation method established in this study is reliable, and could meet the basic needs for polymerase chain reaction-based analysis of M. oryzae.

• Biomedical Science Letters
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• v.28 no.4
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• pp.229-236
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• 2022

To prevent cervical cancer, human papillomavirus (HPV) bivalent and quadrivalent vaccinations are common, but there is a need for a vaccination system based on the high-risk human papillomavirus (HR-HPV) genotype that differs by region. This study aimed to investigate the prevalence of HPV and the distribution of HR-HPV genotypes in 2,014 women who were not vaccinated against HPV. In this study, HPV DNA testing was performed on 2,014 women not vaccinated against HPV and who visited the Busan Obstetrics and Gynecology Department from September 2020 to July 2021. In addition, liquid-based cytology (LBC) test was performed on 493 cases of HR- HPV genotype infection confirmed by HPV DNA test. The prevalence of HPV among women in Busan was positive in 609 (30.2%) out of 2,014 cases. Among the 609 HPV-positive cases, HR-HPV infection accounted for 493 cases (81.0%), which is a high proportion. Of the total 493 HR-HPV infection cases, liquid-based cytology (LBC) was within normal limits (WNL) in 266 cases (54.0%), atypical squamous cells of undetermined significance (ASCUS) in 97 cases (19.7%), low-grade squamous intraepithelial lesion (LGSIL) in 88 cases (17.8%), and high-grade squamous intraepithelial lesion (HGSIL) in 42 cases (8.5%). Single HR-HPV 52 and 16 accounted for the highest and second highest infection rates, respectively. The high infection rate among women aged 18~39 underscores the need for continuous monitoring. In addition, when there were abnormal findings in the cervical epithelium, HPV 52 was the most common, while in the case of HGSIL, HPV 16 was the most common. The HR-HPV genotypes related to cervical cancer should be continuously collected and monitored for use in health policies, including local and national vaccinations.

• Biomedical Science Letters
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• v.11 no.1
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• pp.51-56
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• 2005

The detection of high-risk human papilloma virus (HPV) allows us to predict the presence and future development of cervical intraepitheliallesion. In this study, we compared Hybrid Capture II and DNA chip methods for detection of HPV in cervical swab samples. And we evaluated the clinical efficacy and diagnostic performance of HPV DNA chip and Hybrid Capture II for detecting HPV in cervical neoplastic lesions. Seventy four patients were classified into three groups according to their histologic diagnosis: Group I (nonspecific chronic cervicitis), Group II (low-grade squamous intraepithelial lesion (SIL); koilocytosis, and mild dysplasia), and Group III (high-grade SIL;, moderate, severe dysplasia and in situ carcinoma). Cytologic diagnosis were based on the Bethesda System. Hybrid Capture II and DNA chip methods were performed to detect HPV. In 41 of the 74 cervical samples $(55.4\%)$, HPV DNAs were detected by Hybrid Capture II. In Group III, HPV-positive cases were detected in 15 $(20.3\%)$ of 74 patients by Hybrid Capture II. 25 patients with ASCUS cytology were histopathologically examined: 9 cases $(36\%)$ were Group II. In 18 patients with low-grade SIL cytology, 13 cases $(72.2\%)$ were Group II and 3 cases $(16.7\%)$ were Group III. 12 cases $(92.3\%)$ were Group ill of 13 patients with high-grade SIL cytology. The sensitivity of each test was $82\%$ in Hybrid Capture II and $53.9\%$ in DNA chip test. And the specificity was $74.3\%,\;85.7\%$ in Hybrid Capture II and DNA chip. In conclusion, Hybrid Capture II test is more sensitive than DNA chip in detecting women with cervical neoplastic lesions. Especially, in diagnosing of ASCUS, Hybrid Capture II test is more sensitive. Therefore, Hybrid Capture II test for cancer-associated HPV DNA is a viable option in the management of women with ASCUS.

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.657-665
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• 2023

The root-lesion nematode Pratylenchus spp. is the most important plantparasitic nematode due to its worldwide distribution, wide host ranges, and migratory endoparasitic characteristics. One population of Pratylenchus collected from the giant pussy willow (Salix chaenomeloides Kimura) in the Andong area as part of a nematode survey in Korea was characterized morphologically and by molecular methods. The analysis of morphological measurements and morphometric characteristics, as well as DNA sequencing of the rRNA large subunit (LSU) D2/D3 expansion segments and the internal transcribed spacer (ITS) gene sequence, confirmed the identity of this population as P. hippeastri. This study is the first report of P. hippeastri associated with Salix chaenomeloides in Korea and worldwide. Further studies on distribution and pathogenicity in different P. hippeastri host crops, such as grapevines, strawberries, and apples, are necessary. The taxonomic keys to 16 Pratylenchus species in Korea are provided.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.7
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• pp.3003-3007
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• 2015

Objective: To explore the application of multiplex nested methylated specific polymerase chain reaction (PCR) in the early diagnosis of epithelial ovarian carcinoma (EOC). Materials and Methods: Serum and fresh tissue samples were collected from 114 EOC patients. RUNX3, TFPI2 and OPCML served as target genes. Methylation levels of tissues were assessed by multiplex nested methylated specific PCR, the results being compared with those for carcinoma antigen 125 (CA125). Results: The serum free deoxyribose nucleic acid (DNA) methylation spectrum of EOC patients was completely contained in the DNA spectrum of cancer tissues, providing an accurate reflection of tumor DNA methylation conditions. Serum levels of CA125 and free DNA methylation in the EOC group were evidently higher than those in benign lesion and control groups (p<0.05). Patients with early EOC had markedly lower serum CA125 than those with advanced EOC (p<0.05), but there was no significant difference in free DNA methylation (p>0.05). The sensitivity, specificity and positive predicative value (PPV) of multiplex nested methylated specific PCR were significantly higher for detection of all patients and those with early EOC than those for CA125 (p<0.05). In the detection of patients with advanced EOC, the PPV of CA125 detection was obviously lower than that of multiplex nested methylated specific PCR (p>0.05), but there was no significant difference in sensitivity (p>0.05). Conclusions: Serum free DNA methylation can be used as a biological marker for EOC and multiplex nested methylated specific PCR should be considered for early diagnosis since it can accurately determine tumor methylation conditions.