• Korean Journal of Microbiology
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• v.53 no.1
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• pp.20-28
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• 2017

Physical sterilization methods using ultraviolet radiation and ionizing radiation such as gamma ray and electron beam are applied in various industry fields due to disinfection effects and economic efficiency but may also cause microbial mutation. In this research, Salmonella enterica and Escherichia coli strains were treated with ionizing and ultraviolet radiation and their survival rate, mutation rate, and DNA damage were studied to evaluate the genetic safety. The survival rate of the strains decreased drastically as the irradiation dose of ultraviolet ray, gamma ray, and electron beam increased, and over 90% of the strain was exterminated at a dosage of $0.40{\sim}25.06mJ/cm^3$, 0.11~0.22 kGy, 0.14~0.53 kGy respectively. In SOS / umu-test, genotoxicity causing DNA damage was identified in all samples. In Ames test, back-mutation rate increased to $3.82{\times}10^{-4}$ and $9.84{\times}10^{-6}$ respectively when exposed to ultraviolet ray and gamma ray. At exposure to ultraviolet ray, gamma ray, and electron beam with dosage of over 99.99% extinction rate of S. enterica TA100, back-mutation rate increased 347 times, 220 times, 0.6 times respectively to the spontaneous back-mutation rate. Rifampicin resistance mutation rate of E. coli CSH100 exposed to ultraviolet ray, gamma ray, and electron beam was $2.46{\times}10^{-6}$, $1.66{\times}10^{-6}$, $4.12{\times}10^{-7}$ respectively. Therefore, gamma radiation is effective in microorganism control from the perspective of disinfection and electron beam has the advantage of sterilizing with little DNA damage and bacterial mutation.

• Journal of Radiation Protection and Research
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• v.22 no.1
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• pp.15-21
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• 1997

In vitro somatic mutation induced by ${\gamma}$-radiation and pentachlorophenol(PCP) which is representative of chemical pollutant was measured at the hypoxanthine-guanine phosphoribosyl transferase(hprt) locus in human T- lymphocytes by a cell cloning assay. Mutant cells were selected by their ability to form a clone in the presence of purine analogue 6-thioguanine. The mutant frequencies by ${\gamma}$-irradiation to a dose of 1.0 Gy, 2.0 Gy and 3.0 Gy were 40%, 400% and 750% higher than those in controls. Significant changes were not observed in mutant frequencies in the 0.2 Gy and 0.5 Gy irradiated groups. When the doses of PCP were 15 ppm, 25 ppm and 50 ppm, the mutant frequencies increased by 30%, 90% and 520%, respectively. No changes were observed in the 10 ppm treated group. Similar types of dose-response relationship were shown in the two different mutagens. Reverse transcriptase/polymerase chain reaction technique(RT/PCR) was needed for the mutation spectrum to discriminate combined exposure to radiation and chemicals.

• Radiation Oncology Journal
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• v.33 no.2
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• pp.149-154
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• 2015

Purpose: We performed exome sequencing in a breast cancer family without BRCA mutations. Materials and Methods: A family that three sisters have a history of breast cancer was selected for analysis. There were no family members with breast cancer in the previous generation. Genetic testing for BRCA mutation was negative, even by the multiplex ligation-dependent probe amplification method. Two sisters with breast cancer were selected as affected members, while the mother of the sisters was a non-affected member. Whole exome sequencing was performed on the HiSeq 2000 platform with paired-end reads of 101 bp in the three members. Results: We identified 19,436, 19,468, and 19,345 single-nucleotide polymorphisms (SNPs) in the coding regions. Among them, 8,759, 8,789, and 8,772 were non-synonymous SNPs, respectively. After filtering out 12,843 synonymous variations and 12,105 known variations with indels found in the dbSNP135 or 1000 Genomes Project database, we selected 73 variations in the samples from the affected sisters that did not occur in the sample from the unaffected mother. Using the Sorting Intolerant From Tolerant (SIFT), PolyPhen-2, and MutationTaster algorithms to predict amino acid substitutions, the XCR1, DLL1, TH, ACCS, SPPL3, CCNF, and SRL genes were risky among all three algorithms, while definite candidate genes could not be conclusively determined. Conclusion: Using exome sequencing, we found 7 variants for a breast cancer family without BRCA mutations. Genetic evidence of disease association should be confirmed by future studies.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2000.11a
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• pp.15-15
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• 2000

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.1
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• pp.82-86
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• 1976

'Radiation No. 6' the first mutant variety of naked barley in Korea was developed from Bangju as .a mother variety. The new variety was characterized by early maturity, short-culm and stablized high yield by the increased number of spikes. 'Radiation No. 6' was registered as a leading variety in 1974, .after 7 years since induction of mutation started.of mutation started.

• Asian Journal of Turfgrass Science
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• v.22 no.1
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• pp.25-34
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• 2008

This study was conducted to determine the optimum dose ranges for a mutation breeding based on the observations of a seed germination and an early growth in turfgrasses. Three warm season (Zoysiagrass, Bermudagrass, and Seashore paspalum) and four cool season turfgrasses (Kentucky bluegrass, Tall fescue, Perennial ryegrass, and Creeping bentgrass) were used in this study. We investigated the percentage of a seed germination and a seedling growth after irradiating the turfgrass seeds with various doses of gamma-ray (50, 100, 150, 200, 250, 300, 400, and 500 Gy). After 24 h with a gamma irradiation, the seeds were sown on the wet filter paper in a petri dish and maintained for 3 weeks at 30$^{\circ}C$ for the warm season turfgrasses and at 25$^{\circ}C$ for the cool season turfgrasses. Data on a seed germination and a seedling growth with three replications were collected. The percentage of seed germination was decreased with an increase of the gamma-ray dose. Shoot and root growth, and the fresh weight were decreased significantly as the radiation dose was increased. A radiation dose indicating a 50% growth inhibition ($LD_{50}$) with a gamma irradiation was varied among those turfgrass species used, with the highest at about 500 Gy for bermudagrass and the lowest at 100Gy for tall fescue. The optimum dose for a gamma irradiation for a selection of turfgrass mutants was considered to be about 300, 150, 500, 150, 200, 100 and 200 Gy for zoysiagrass, seashore paspalum, bermudagrass, Kentucky bluegrass, perennial ryegrass, tall fescue, and creeping bentgrass, respectively.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.373-378
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• 2011

Our aim was to investigate the genotoxicity of ambient air in the Krak$\acute{o}$w area after Fukushima Nuclear Power Plant (NPP) accident and compare with results from Chernobyl fallout. For the detection of ambient air genotoxicity the technique for screening gene mutation frequency in somatic cells of the $Tradescantia$ stamen hairs ($Trad$-SH assay) was used. Since 11th of March 2011 (Fukushima NPP accident), several pots containing at least 15 shoots of bioindicating plants were exposed to ambient air at 2 sites in the Krak$\acute{o}$w surrounding area, one in the city center, and about 100 pots in a control site (in the glasshouse of the Institute of Nuclear Physics) Continuous screening of mutations was performed. Progenies of 371,090 cells exposed were analyzed. Mutation frequency obtained in the first 10 days has shown a mean control level (GMF*100=$0.06{\pm}0.01$). At scoring period related to influence of a potential Fukushima fallout, a significant increase of gene mutation frequencies above the control level was observed at each site in the range, 0.10~0.33 depending on the location, (mean value for all sites GMF*100=$0.19{\pm}0.05$) that was associated with a strong expression of toxic effects. In the reported studies following the Chernobyl NPP accident monitoring $in$ $situ$ of the ambient air genotoxicity was performed in the period since April $29^{th}$ till June $3^{rd}$ 1986 also with Trad-SH bioindicator. In general, mutation frequency increases due to Chernobyl fallout(GMF*100=$0.43{\pm}0.02$) were corresponding to fluctuation of radioactivity in the air reported from physical measures, and to published reports about increase in chromosome aberration levels. Although, recent data obtained from monitoring of the ambient air quality in the Krak$\acute{o}$w and surroundings are lower when compared to results reported after Chernobyl NPP accident, though results express a significant increase above the control level and also are corresponding with increased air radioactivity reported from physical measurements. Statistically significant in comparison to control increase in gene mutation rates and more prolonged than that after Chernobyl fallout increase of GMF was observed during the period following the Fukushima NPP failure.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.83-83
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• 2002

To assess the role of 8-oxoguanine glycosylase (OGG1) in the cell defense against radiation injury, the radiation-induced cytotoxicities were compared between the mutant type KG-1 featuring a loss of OGG1 activity due to a homozygous mutation of Arg 229 G1n, and the wild type U937.(omitted)

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.24
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• pp.10893-10898
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• 2015

Several molecular markers have been proposed as predictors of outcome in patients with glioblastomas. We investigated the prognostic significance of $O^6$-methylguanine-DNA methyltransferase (MGMT) promoter methylation and TP53 mutation status dependent on isocitrate dehydrogenase 1 (IDH1) mutation in glioblastoma patients. A cohort of 78 patients with histologically confirmed glioblastomas treated with radiation therapy and chemotherapy were reviewed retrospectively. We evaluated the prognostic value of MGMT promoter methylation and TP53 mutation status with regard to progression-free survival (PFS) and overall survival (OS). It was revealed that mutations in IDH1, promoter methylation of MGMT, TP53 mutation, age, Karnofsky performance status (KFS), and extension of resection were independent prognostic factors. In patients with an IDH1 mutation, those with an MGMT methylation were associated with longer PFS (p=0.016) and OS (p=0.013). Nevertheless, the presence of TP53 mutation could stratify the PFS and OS of patients with IDH1 wild type (p=0.003 and 0.029 respectively, log-rank). The MGMT promoter methylation and TP53 mutation were associated with a favorable outcome of patients with and without mutant IDH1, respectively. The results indicate that glioblastomas with MGMT methylation or TP53 mutations have improved survival that may be influenced by IDH1 mutation status.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.43-43
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• 2018

Mutation breeding by radiation is useful for improving various crop species. Up to now, a total of 170 soybean mutant varieties have been released in the world, which is the second most registered varieties after rice. Despite the economic importance of soybean, there have been no TRAP marker system studies on genetic relationships between/among mutant lines. To develop a strategy of Mutant Diversity Pool (MDP) conservation, a study on the genetic diversity of 210 soybean mutant lines (8 cultivars and 202 mutants) was performed through a TRAP analysis. Sixteen primer combinations amplified a total of 551 fragments. The highest (84.00%) and lowest (32.35%) polymorphism levels were obtained with primers MIR157B + Ga5 and B14G14B + Ga3, respectively. The mean PIC values 0.15 varied among the primer combination ranging from 0.07 in B14G14B + Sal2 to 0.23 in MIR157B + Sa4. Phylogenetic, principal component analysis (PCA) and structure analysis indicated that the 210 lines belong to four groups based on the 16 combination TRAP markers. AMOVA showed 21.0% and 79.0% variations among and within the population, respectively. Overall, the genetic similarity of each cultivar and its mutants were higher than within other mutant populations. Our results suggest that the TRAP marker system may be useful for assessing the genetic diversity among soybean mutants and help to improve our knowledge of soybean mutation breeding.