• Biomolecules & Therapeutics
• /
• v.10 no.3
• /
• pp.193-199
• /
• 2002

The arylamine N-acetyltransferases (NATs) are a family of enzymes that N-acetylate mylhydrazines and arylamines through transfer of an acetyl group from acetyl coenzyme A. This activity was found to vary among individuals as a Mendalian trait and the basis of the genetic differences in human NAT activity is one of the best of the genetic studied examples of pharmacogenetic variation. The classical N-acetylation polymorphism is regulated at the NAT2 locus, which segregates individuals into rapid, intermediate, and slow acetylator phenotypes. In this study, the relationship between NAT2 activity phenotype using HPLC:UV assay for the determination of dapsone and monoacetyldapsone in plasma and NAT2 genotype by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) was investigated in the F2 hybrid (Fischer 344 vs Wistar-Kyoto) rats. Three Common mutant alleles at the NAT2 gene locus have been identified in the F2 generation progeny of Fischer 344 rats as raid acetylator and Wistar-Kyoto rats as slow acetylator segregated into three modes (low, intermediates, and high) with simple Mendelian inheritance. The metabolic activity of NAT2 of the intermediate and rapid acetylators is significant1y greater than slow acetylator, but the metabolic activity of rapid acetylator is not significantly different from Intermediate type. Therefore, we could observe that complete trimodal NAT2 genotypic alleles and incomplete trimodal NAT2 metabolic phenotypic distribution in tile F2 hybrid rats. These observations suggest that the relationships between NAT2 genotype and metabolic phenotype exists and F2 hybrid (Fischer 344: Wistar-Kyoto) animal models about NAT2 polymorphism might be applied in the toxicity and pharmacogenetic studies of arylamine drugs and carcinogens.

• Parasites, Hosts and Diseases
• /
• v.47 no.4
• /
• pp.337-344
• /
• 2009

In a previous study, we reported our discovery of Acanthamoeba contamination in domestic tap water; in that study, we determined that some Acanthamoeba strains harbor endosymbiotic bacteria, via our molecular characterization by mitochondrial DNA restriction fragment length polymorphism (Mt DNA RFLP). Five (29.4%) among 17 Acanthamoeba isolates contained endosymbionts in their cytoplasm, as demonstrated via orcein staining. In order to estimate their pathogenicity, we conducted a genetic characterization of the endosymbionts in Acanthamoeba isolated from domestic tap water via 16S rDNA sequencing. The endosymbionts of Acanthamoeba sp. KA/WP3 and KA/WP4 evidenced the highest level of similarity, at 97% of the recently published 16S rDNA sequence of the bacterium, Candidatus Amoebophilus asiaticus. The endosymbionts of Acanthamoeba sp. KA/WP8 and KA/WP12 shared a 97% sequence similarity with each other, and were also highly similar to Candidatus Odyssella thessalonicensis, a member of the $\alpha$-proteobacteria. The endosymbiont of Acanthamoeba sp. KA/WP9 exhibits a high degree of similarity (85-95%) with genus Methylophilus, which is not yet known to harbor any endosymbionts. This is the first report, to the best of our knowledge, to show that Methylophilus spp. can live in the cytoplasm of Acanthamoeba.

• Journal of Preventive Medicine and Public Health
• /
• v.38 no.4
• /
• pp.437-442
• /
• 2005

Objectives : DNA methylation is one of the best characterized epigenetic mechanisms that play a regulatory role in genome programming and imprinting during embryogenesis. In this present study, we investigated the association between DNA methylation in the human placenta and the maternal folate and homocysteine concentrations on the Methylenetetrahydrofolatereductase (MTHFR) genetic polymorphism during pregnancy. Methods : We investigated 107 pregnant women who visited Ewha Woman's University Hospital for prenatal care during their $24{\sim}28$ weeks-period of gestation. During the second trimester, we measured the serum homocysteine and folate concentrations . The MTHFR 677 genetic polymorphism was determine by performing PCR-RFLP assay. The expression of DNA methylation in the human placentas was estimated by using immunohistochemistry method. Results : Serum folate was negatively correlated with the serum homocysteine concentration for all the MTHFR genotypes. We found positive correlation between the folate concentrations and the DNA methylation in the human placenta (p<0.05). An increasing concentration of homocysteine was associated with reduced DNA methylation in the human placenta. The coefficient value was -2.03 (-3.77, -0.29) on the regression model (p<0.05). Conclusion : These findings suggest that the maternal folate and homocysteine levels along with the MTHFR 677 genetic polymorphism during pregnancy affect the DNA methylation in the human placenta.

• Korean Journal Plant Pathology
• /
• v.13 no.4
• /
• pp.239-243
• /
• 1997

In August 1996, phyllody disease of sesame (Sesamum indicum L.) caused by phytoplasmas was observed at Boeun, Chungbuk Province, Korea. Symptoms included extreme proliferation of growing tips and numerous small leaves, giving the infected plant a witche's-broom effect. Parts or all of the floral parts were transformed into green leaf-like structures, and little or no seeds were produced. Transmission Electron microscopy revealed the presence of phytoplasmas in the phloem sieve elements of infected plant. Since the infected sesame plants were growing near by phytoplasma infected jujubes (Zizyphus jujubu), we tried a polymerase chain reaction (PCR) technique to identify these two causal phytoplasmas. The DNA extracted from the stems of infected sesame plant was PCR-amplified using a primer set specific to 16S rRNA gene of known phytoplasmas. The amplification generated a 1.4kb band in both sesame samples and phytoplasma-infected jujubes, which also suggests the sesame plants were infected with phytoplasmas. The restriction digestion of the amplified band by four different enzymes, AluI, HaeIII, HinfI or TaqI revealed that the phytoplasmas infecting jujubes and sesame plants were of different groups.

• The Plant Pathology Journal
• /
• v.32 no.2
• /
• pp.136-144
• /
• 2016

Pseudomonas fluorescens pc78 is an effective biocontrol agent for soil-borne fungal diseases. We previously constructed a P43-gfp tagged biocontrol bacteria P. fluorescens pc78-48 to investigate bacterial traits in natural ecosystem and the environmental risk of genetically modified biocontrol bacteria in tomato rhizosphere. Fluctuation of culturable bacteria profile, microbial community structure, and potential horizontal gene transfer was investigated over time after the bacteria treatment to the tomato rhizosphere. Tagged gene transfer to other organisms such as tomato plants and bacteria cultured on various media was examined by polymerase chain reaction, using gene specific primers. Transfer of chromosomally integrated P43-gfp from pc78 to other organisms was not apparent. Population and colony types of culturable bacteria were not significantly affected by the introduction of P. fluorescens pc78 or pc78-48 into tomato rhizosphere. Additionally, terminal restriction fragment length polymorphism profiles were investigated to estimate the influence on the microbial community structure in tomato rhizosphere between non-treated and pc78-48-treated samples. Interestingly, rhizosphere soil treated with strain pc78-48 exhibited a significantly different bacterial community structure compared to that of non-treated rhizosphere soil. Our results suggest that biocontrol bacteria treatment influences microbial community in tomato rhizosphere, while the chromosomally modified biocontrol bacteria may not pose any specific environmental risk in terms of gene transfer.

• Food Science of Animal Resources
• /
• v.26 no.1
• /
• pp.121-126
• /
• 2006

Major milk proteins have considerable variane which comes from substitution and deletions in their amino arid sequences. Variants in genes that code for milk proteins, such as ${\beta}$-lactoglobulin (${\beta}-LG$) have been established as genetic markers for milk production and milk protein composition in dairy cattle. The effect of ${\beta}-LG$ variant on milk production traits, such as milk yield. fat yield, protein yield, fat percentage and protein percentage, was estimated for 482 Holstein cows in the first lactation. The ${\beta}-LG$ variants were determined by PCR-RFLP technique at the DNA level. Single trait linear model was used for the statistical analysis of the data. Results of this study indicated that ${\beta}-LG$ variants affected significantly protein yield (p<0.05) and fat percentage (p<0.05). Animals with the AA variant produced 31kg of milk protein more than animals with the BB variant. On the contrary, cows with the BB variant had fat percentage higher by 0.35 and 0.32% compared with cows with the AA and AB variants, respectively. No associations between the ${\beta}-LG$ variants and milk yield, protein percentage and fat yield were found Therefore, milk production traits could be improved through ${\beta}-LG$ typing by increasing the frequency of A variant for protein yield or the frequency of B variant for fat content in Holstein dairy cattle population.

• Journal of Preventive Medicine and Public Health
• /
• v.37 no.4
• /
• pp.321-328
• /
• 2004

Objectives : The purpose of this study was to investigate the effect of genetic polymorphism of cytochrome P450 2E1 (CYP2E1) and aldehyde dehydrogenase 2 (ALDH2) on the xylene metabolism. Methods : Among 247 workers, 116 were occupationally exposed to xylene and 131 were not. Workers exposed to xylene had different work such as spray, touch-up, mix & assist, and pre-treat. Questionnaire variables were age, sex, use of personal protective equipment, smoking, previous night's drinking and work duration. The urinary methylhippuric acid was measured in the urine collected in the afternoon and corrected by urinary creatinine concentration. The genotypes of CYP2E1 and ALDH2 were investigated by using PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) methods with DNA extracted from venous blood. Results : 1. The urinary concentrations of o-, m-, and p-methylhippuric acid and total methylhippuric acid in the exposed group were significantly higher than those in the non-exposed group (p<0.001). 2. In multiple regression analysis, the urinary methylhippuric acid concentration was significantly influenced by exposure grade (Job-exposure matrixes), smoking, drug use and kind of protective equipment (p<0.1). 3. Genetic polymorphism of CYP2E1 and ALDH2 did not affect urinary methylhippuric acid level in the exposed group (p>0.05). Conclusions : Exposure grade, smoking, drug use and kind of protective equipment affected urinary methylhippuric acid level, whereas genetic polymorphism of CYP2E1 and ALDH2 did not. However, further investigation for the effect of genetic polymorphism on the metabolism of xylene with a larger sample size is needed.

• Molecular & Cellular Toxicology
• /
• v.1 no.4
• /
• pp.217-223
• /
• 2005

To assess that the XRCC1 399Gln variant contributes to sensitivity to ionizing radiation treatment and is associated with progression-free and overall survival, one hundred and ninety-five lung cancer patients were recruited at the Asan Medical Center from 2000 to 2003. We determined the genotypes of the XRCC1 genes by PCR-RFLP. Kaplan-Meier survival curves and the log-rank test were used to analyze the effects of genotypes on survival. Hazard ratios, adjusted for age, sex, and other potential confounders, were calculated using the Cox-proportional hazard model. Patients carrying the 399Gln variant allele under radiotherapy only had a shorter progression-free and overall survival than those with the 399Arg homozygote. However, when we analyzed for the effect of the XRCC1 Arg399Gln polymorphism in the combined treatment of surgical resection and radiotherapy, we found that patients with the 399Gln variant allele had a longer progression-free and overall survival. This study shows different associations between the XRCC1 Arg399Gln polymorphism and progression-free or overall survival depending on treatment protocol in patients with NSCLC.

• Journal of Microbiology
• /
• v.44 no.4
• /
• pp.409-416
• /
• 2006

Clarithromycin resistance in Helicobacter pylori is a principal cause of failure of eradication therapies, and its prevalence varies geographically. The IceA gene is a virulence factor associated with clinical outcomes. The objective of this study was to determine the current state of clarithromycin resistance prevalence, and to investigate the role of iceA genotypes in 87 Turkish adult patients (65 with functional dyspepsia and 22 with duodenal ulcer). A2143G and A2144G point mutations were tested by PCR-RFLP for clarithromycin resistance. Among the patients in the study, 28 patients were tested by agar dilution as well. Allelic variants of the iceA gene were identified by PCR. A total of 24 (27.6%) strains evidenced one of the mutations, either A2143G or A2144G. IceA1 was found to be positive in 28 of the strains (32.2 %), iceA2 was positive in 12 (13.8 %) and, both iceA1 and iceA2 were positive in 22 (25.3 %) strains. In conclusion, we discovered no relationships between iceA genotypes and functional dyspepsia or duodenal ulcer, nor between clarithromycin resistance and iceA genotypes. clarithromycin resistance appears to be more prevalent in Turkish patients.

• The Korean Journal of Mycology
• /
• v.25 no.3 s.82
• /
• pp.161-166
• /
• 1997

Occurrence of Hypoxylon truncatum, known as a symbiont of white jelly mushroom, was first noted and described in Korea. Two stromatal forms reported in North American collections of H. truncatum sensu Miller were also observed in Korean collections. Based on evidences from other studies, polymorphic patterns seen in six enzyme digestions of nuclear Internal Transcribed Spacer (ITS) regions of Korean isolates indicated that the two stromatal forms were genetically distinct. Because there was a clear association of stromatal morphology with genetic differences, the different stromatal forms might be different species. In addition, clear species concept on the species H. truncatum would provide aids in selecting proper strain for cultivation of white jelly mushrooms.