• Nutrition Research and Practice
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• v.4 no.5
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• pp.351-355
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• 2010

Our previous proteomic study demonstrated that oxidative stress and antioxidant delphinidin regulated the cellular level of $p27^{kip1}$ (referred to as p27) as well as some heat shock proteins in human colon cancer HT 29 cells. Current study was conducted to validate and confirm the regulation of these proteins using both in vitro and in vivo systems. The level of p27 was decreased by hydrogen peroxide in a dose-dependent manner in human colon carcinoma HCT 116 (p53-positive) cells while it was increased upon exposure to hydrogen peroxide in HT 29 (p53-negative) cells. However, high concentration of hydrogen peroxide (100 ${\mu}M)$ downregulated p27 in both cell lines, but delphindin, one of antioxidative anthocyanins, enhanced the level of p27 suppressed by 100 ${\mu}M$ hydrogen peroxide. ICR mice were injected with varying concentrations of hydrogen peroxide, delphinidin and both. Western blot analysis for the mouse large intestinal tissue showed that the expression of p27 was upregulated by 25 mg/kg BW hydrogen peroxide. To investigate the association of p27 regulation with hypoxia-inducible factor 1-beta (HIF-$1{\beta}$), the level of p27 was analyzed in wild-type mouse hepatoma hepa1c1c7 and Aryl Hydrocarbon Nuclear Translocator (arnt, HIF-$1{\beta}$)-defective mutant BPRc1 cells in the absence and presence of hydrogen peroxide and delphinidin. While the level of p27 was responsive to hydrogen peroxide and delphinidin, it remained unchanged in BPRc1, suggesting that the regulation of p27 requires functional HIF-$1{\beta}$. We also found that hydrogen peroxide and delphinidin affected PI3K/Akt/mTOR signaling pathway which is one of upstream regulators of HIFs. In conclusion, hydrogen peroxide and antioxidant delphinidin seem to regulate intracellular level of p27 through regulating HIF-1 level which is, in turn, governed by its upstream regulators comprising of PI3K/Akt/mTOR signaling pathway. The results should also encourage further study for the potential of p27 as a biomarker for intracellular oxidative or antioxidant status.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5415-5420
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• 2013

Background: Cell cycle deregulation is a major component of carcinogenesis. The p53 tumor suppressor gene plays an important role in regulating cell cycle arrest, and mouse double minute 2 (MDM2) is a key regulator of p53 activity and degradation. Abnormal expression of p53 and MDM2 occurs in various cancers including lung cancer. Methods: We investigated the distribution of the p53 Arg72Pro (rs1042522) and MDM2 SNP309 (rs2279744) genotypes in patients and healthy control subjects to assess whether these single nucleotide polymorphisms (SNPs) are associated with an increased risk of lung adenocarcinomas in Chinese female non-smokers. Genotypes of 764 patients and 983 healthy controls were determined using the TaqMan SNP genotyping assay. Results: The p53 Pro/Pro genotype (adjusted OR = 1.55, 95% CI = 1.17-2.06) significantly correlated with an increased risk of lung adenocarcinoma, compared with the Arg/Arg genotype. An increased risk was also noted for MDM2 GG genotype (adjusted OR = 1.68, 95% CI = 1.27-2.21) compared with the TT genotype. Combined p53 Pro/Pro and MDM2 GG genotypes (adjusted OR = 2.66, 95% CI = 1.54-4.60) had a supermultiplicative interaction with respect to lung adenocarcinoma risk. We also found that cooking oil fumes, fuel smoke, and passive smoking may increase the risk of lung adenocarcinomas in Chinese female non-smokers who carry p53 or MDM2 mutant alleles. Conclusions: P53 Arg72Pro and MDM2 SNP309 polymorphisms, either alone or in combination, are associated with an increased lung adenocarcinoma risk in Chinese female non-smokers.

• Journal of Nutrition and Health
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• v.35 no.8
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• pp.870-879
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• 2002

The purpose of this study was to investigate the obesity and state of dietary intake of 216 young Korean females, and the influence of $\beta$-II, III Adrenergic receptor (AR) gene polymorphism upon obesity and dietary intake. The average weight, height and BMI of the subjects were 160 cm, 54 kg, and 20.9 kg/$m^2$, respectively. The average triceps skinfold thickness, waist circumference, hip circumference and WHR were 21.7mm, 73.1cm, 93.3cm and 0.78, respectively. The results of body composition measurement using bioimpedance method, average body fluid, body protein, mineral mass and body fat were 29.271, 7.22 kg, 6.79 kg and 19.16 kg, respectively. A dietary survey was conducted using 24-hour recall method. Average calorie intake was 1621 ㎉, which is 81% of Korean RDA. We detected 182 (84.3%) Gln27 (QQ) homozygotes and 34 (15.7%) Gln27Glu (QE) heterozygotes for $\beta$-II AR polymorphism. For $\beta$-III AR polymorphism, we detected 163 (75.5%) Trp64 (WW) and 53 (24.5%) Trp 64Arg (WR). The results of comparing of obesity by $\beta$-II AR gene polymorphism, obesity index and BMI of QE type were slightly higher than those of the QQ type. For $\beta$-III AR gene polymorphism, the mean BMI, obesity index, fat mass and percent body fat (%) of the WR type were significantly higher than those of the WW type (p < 0.05). These findings suggest that genetic variability in the human $\beta$-III AR is associated with obesity among young Korean females. We also evaluated the effect of the simultaneous presence of the $\beta$-II AR and $\beta$-III AR polymorphism on obesity. We found that the BMI and obesity index of the mutant type in both $\beta$-II AR and $\beta$-III AR were significantly higher than those of the type that has only one gene mutation or has no mutation (p < 0.05), indicating a synergistic effect of $\beta$-II AR and $\beta$-III AR polymorphism on obesity. No association was found between $\beta$-II Ad or $\beta$-III AR polymorphism and dietary intake.

• Biomedical Science Letters
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• v.11 no.2
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• pp.165-173
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• 2005

A potent demethylating agent, 5-Azacytidine (5-AzaC) has been widely used as in many studies on DNA methylation, regulation of gene expression, and cancer biology. The mechanisms of the demethylating activity were known to be formation of complex between DNA and DNA methyltransferase (MTase), which depletes cellular MTase activity. However, 5-AzaC can also induce hypermethylation of a transgene in a transgenic cell line, G12 cells and it was explained as a result of defense mechanisms to inactivate foreign gene(s) somehow. This finding evoked the question that whether the phenomenon of hypermethylation induced by 5-AzaC is limited to the transgene or it can be occurred in endogenous gene(s). In order to answer the question, mutagenicity test of 5-AzaC and molecular characterization of mutants obtained from the test were performed using an endogenous gene, thymidine kinase (tk) in Chinese hamster V79 cells. When V79 and V79-J3 subclone cells were treated with 1, 2.5 ,5, $10{\mu}M$ of 5-AzaC for 48 hours, their maximum mutant frequencies were revealed as $6\times10^{-3}\;at\;5{\mu}M$(350-fold induction over background) and $8\times10^{-3}\;at\;2.5{\mu}M$ (l,800-fold induction over background) respectively. Since the induction rates were too high to be induced by true mutations, many trifluorothymidine (TFT)-resistant $(TFT^R)$ cells were subjected to Northern blot analysis to check the presence of tk transcripts. Surprisingly, all clones tested possessed the transcripts in a similar level, that implicates the $TFT^R$ phenotype induced by 5-AzaC has not given rise to hypermethylation of the gene in spite of unusually high mutation frequency. In addition, it has shown that the TK activity in the pool of 5-AzaC-induced $TFT^R$ cells has about a half of that in spontaneously-induced $TFT^R$ cells or in non-selected parental V79-J3 cells. This result suggests that the mechanism(s) underlying the TFT-resistance between spontaneously occurred and 5-AzaC-induced cells may be different. These findings have shown that the $TFT^R$ phenotype induced by 5-AzaC has not given rise to hypermethylation of the tk gene, and 5-AzaC may be induced by one or combined pathways among many drug resistance mechanisms. The exact mechanisms for the 5-AzaC-induced $TFT^R$ phenotype remain to elucidate.

• BMB Reports
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• v.49 no.5
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• pp.297-302
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• 2016

Loss of pancreatic β-cells by oxidative stress or cytokines is associated with diabetes mellitus (DM). DJ-1 is known to as a multifunctional protein, which plays an important role in cell survival. We prepared cell permeable wild type (WT) and mutant type (M26I) Tat-DJ-1 proteins to investigate the effects of DJ-1 against combined cytokines (IL-1β, IFN-γ and TNF-α)-induced RINm5F cell death. Both Tat-DJ-1 proteins were transduced into RINm5F cells. WT Tat-DJ-1 proteins significantly protected against cell death from cytokines by reducing intracellular toxicities. Also, WT Tat-DJ-1 proteins markedly regulated cytokines-induced pro- and anti-apoptosis proteins. However, M26I Tat-DJ-1 protein showed relatively low protective effects, as compared to WT Tat-DJ-1 protein. Our experiments demonstrated that WT Tat-DJ-1 protein protects against cytokine-induced RINm5F cell death by suppressing intracellular toxicities and regulating apoptosisrelated protein expression. Thus, WT Tat-DJ-1 protein could potentially serve as a therapeutic agent for DM and cytokine related diseases.

• Korean Journal of Microbiology
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• v.43 no.2
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• pp.77-82
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• 2007

In a homothallic ascomycete Aspergillus nidulans, sexual development is inhibited by various environmental stresses such as acetate medium, visible light and high osmolarity conditions. In order to study the genes involved in this stress-related regulatory network, we first attempted to isolate mutants that could develop cleistothecia even in the presence of any of those stresses including intensive visible light. More than 10,000 mutants were screened and 167 mutants were analyzed. Among them, 152 mutants underwent sexual development under the single stress condition of either high osmotic, high acetate or light condition but no sexual development in more than two stresses. Six mutants can produce cleistothecia under light or acetate stress but not in salt stress. Moreover, 6 mutants showed the ability to develop cleistothecia under the light but not under the acetate or osmo-stress. The mutants were revealed to have independent single gene mutation and grouped into different complementation groups (silA-F). The mutant alleles were all recessive to that of wild type. The light responsiveness of development implies the existence of delicate regulation process including reception and translocation of light signaling and determination of development.

• Korean Journal of Microbiology
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• v.50 no.1
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• pp.1-7
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• 2014

Site-specific incorporation of unnatural amino acids (SSIUA) into protein can be achieved in vivo by coexpression of an orthogonal pair of suppressor tRNA and engineered aminoacyl-tRNA synthetase (ARS) that specifically ligates an unnatural amino acid to the suppressor tRNA. As a step to develop the SSIUA technique in Escherichia coli, here we established a new 2-step screening system that can be used for selecting an ARS variant(s) that ligates an unnatural amino acid to a suppressor tRNA. A positive selection system consists of chloramphenicol acetyl transferase gene containing an amber mutation at the $27^{th}$ residue, and efficiently concentrated amber suppressible ARS with a maximum enrichment factor of $9.0{\times}10^5$. On the other hand, a negative selection system was constructed by adding multiple amber codons in front of a lethal gene encoding the control of cell death B toxin (ccdB) which acts as an inhibitory protein of bacterial topoisomerase II. Amber suppression of ccdB by an orthogonal pair of Saccharomyces cerevisiae tyrosyl-tRNA synthetase (TyrRS) and an amber suppressor tRNA significantly inhibits bacterial growth. This selection system was also able to efficiently remove amber suppressible ARS which could ligate natural amino acids to the suppressor tRNA. Thus, sequential combination of these two selection systems might be able to function as a powerful tool for selecting an ARS variant that specifically ligates an unnatural amino acid to the suppressor tRNA from an ARS mutant pool.

• KSBB Journal
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• v.11 no.1
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• pp.8-14
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• 1996

Bacillus subtillis strains with transition state regulator mutations and a spore mutation were developed for the overexpression of apsE and for the enhancement of expression level. Among the many regulator genes, degU and hpr were chosen as a representative positive and negative regulator for the aprE, respectively. Spo II G was used for the construction of asporogeneous strains. All the mutants were constructed from two protease-deleted strain DB104 and the apsE gene was transformed with an integration vector pMK101. DB104(deg$U^h$(32) $his^+$)::pMK101(Cm) and DB104($\Delta$her(Em))::pMKl01(Cm) show 7-fold and about 2-fold increase in aprE expression level, respectively. But the effect of transition state regulator mutation on the aprE expression was diminished when the integrated aprE gene was amplified by the high concentration of chloramphenicol, i. e. 30 $\mu\textrm{g}$/ml. DB104($\Delta$spoIIG(Pm) degUh(32) his+)::pMK101(Cm) and DB104($\Delta$spoIIG(Pm) $\Delta$hpr(Em))::pMK101 double mutant show 10-fold and 3-fold increase in aprE expression level, respectively. The results suggest that sporulation mutation and transition state regulator mutation have independent and additive effect on the aprE expression, and the same gene dosage effect on the transition state regulator mutation was also identified.

• Journal of Microbiology and Biotechnology
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• v.17 no.9
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• pp.1460-1468
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• 2007

In this study, an approx. 2.5-kb gene fragment including the catalase gene from Rhodospirillum rubrum S1 was cloned and characterized. The determination of the complete nucleotide sequence revealed that the cloned DNA fragment was organized into three open reading frames, designated as ORF1, catalase, and ORF3 in that order. The catalase gene consisted of 1,455 nucleotides and 484 amino acids, including the initiation and stop codons, and was located 326 bp upstream in the opposite direction of ORF1. The catalase was overproduced in Escherichia coli UM255, a catalase-deficient mutant, and then purified for the biochemical characterization of the enzyme. The purified catalase had an estimated molecular mass of 189 kDa, consisting of four identical subunits of 61 kDa. The enzyme exhibited activity over a broad pH range from pH 5.0 to pH 11.0 and temperature range from $20^{\circ}C$ to $60^{\circ}C$C. The catalase activity was inhibited by 3-amino-1,2,4-triazole, cyanide, azide, and hydroxylamine. The enzyme's $K_m$ value and $V_{max}$ of the catalase for $H_2O_2$ were 21.8 mM and 39,960 U/mg, respectively. Spectrophotometric analysis revealed that the ratio of $A_{406}$ to $A_{280}$ for the catalase was 0.97, indicating the presence of a ferric component. The absorption spectrum of catalase-4 exhibited a Soret band at 406 nm, which is typical of a heme-containing catalase. Treatment of the enzyme with dithionite did not alter the spectral shape and revealed no peroxidase activity. The combined results of the gene sequence and biochemical characterization proved that the catalase cloned from strain S1 in this study was a typical monofunctional catalase, which differed from the other types of catalases found in strain S1.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.26-32
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• 2013

Butanol-resistant bacteria were isolated from butanol solvent. The cell growth of isolated strains declined with increasing concentrations of butanol, and isolated strain BRS02 displayed more resistance to 12.5 g/L of butanol than other isolated strains. In addition, strain BRS251, which was resistant to even higher concentrations of butanol, was developed by the mutation of BRS02 using UV. BRS251 could grow in LB medium containing up to 17.5 g/L of butanol, 32.5 g/L of propanol, or 6 g/L of pentanol, whereas the control strain Escherichia coli was found to be tolerant to 7.5 g/L of butanol, 20 g/L of propanol, or 2 g/L of pentanol. The isolated BRS02, a Gram(+) bacterium seen to have a cocci form under the microscope, grew in 6.5% NaCl. According to biochemical tests, BRS02 can metabolize and produce acid with D-galactose, D-maltose, D-mannitol, D-mannose, methyl-${\beta}$-Dglucopyranoside, D-ribose, sucrose, or D-trehalose, as carbon sources. Also, this strain showed resistance to bacitracin, vibriostatic agent O/129, and optochin, alongside positive activities for arginine dihydrolase, ${\alpha}$-glucosidase, and urease. The BRS02 strain was identified as Staphylococcus sp. by analyses of the 16S rRNA gene, phylogenetic tree, and biochemical tests.