• The Plant Pathology Journal
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• v.33 no.4
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• pp.402-409
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• 2017

Cyclic dipeptides (CDPs) are one of the simplest compounds produced by living organisms. Plant-growth promoting rhizobacteria (PGPRs) also produce CDPs that can induce disease resistance. Bacillus vallismortis strain BS07 producing various CDPs has been evaluated as a potential biocontrol agent against multiple plant pathogens in chili pepper. However, plant signal pathway triggered by CDPs has not been fully elucidated yet. Here we introduce four CDPs, cyclo(Gly-L-Pro) previously identified from Aspergillus sp., and cyclo(L-Ala-L-Ile), cyclo(L-Ala-L-Leu), and cyclo(L-Leu-L-Pro) identified from B. vallismortis BS07, which induce disease resistance in Arabidopsis against Pseudomonas syringae infection. The CDPs do not directly inhibit fungal and oomycete growth in vitro. These CDPs require PHYTOALEXIN DEFICIENT4, SALICYLIC ACID INDUCTION DEFICIENT2, and NONEXPRESSOR OF PATHOGENESIS-RELATED PROTEINS1 important for salicylic acid-dependent defense to induce resistance. On the other hand, regulators involved in jasmonate-dependent event, such as ETHYLENE RECEPTOR1, JASMONATE RESPONSE1, and JASMONATE INSENSITIVE1, are necessary to the CDP-induced resistance. Furthermore, treatment of these CDPs primes Arabidopsis plants to rapidly express PATHOGENESIS-RELATED PROTEIN4 at early infection phase. Taken together, we propose that these CDPs from PGPR strains accelerate activation of jasmonate-related signaling pathway during infection.

• The Plant Pathology Journal
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• v.21 no.1
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• pp.7-12
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• 2005

Plant growth-promoting rhizobacteria (PGPR) are a wide range of root-colonizing bacteria with the capacity to enhance plant growth and control plant pathogens. Here we review recent progress that indicate some PGPR strains release a blend of volatile organic compounds (VOCs) that promote growth in Arabidopsis seedlings and induce resistance against Erwinia carotovora subsp. carotovora. In particular, the volatile components 2,3-butanediol and acetoin released exclusively from the PGPR strains triggered the greatest level of growth promotion and induced systemic resistance. Pharmacological applications of 2,3-butanediol promoted the plant growth and induced resistance, while bacterial mutants blocked in 2,3-butanediol and acetoin synthesis was devoid of growth-promotion and induced resistance capacities. The results suggested that the bacterial VOCs play a critical role in the plant growth promotion and induced resistance by PGPR. Using transgenic and mutant lines of Arabidopsis, we provide evidences that the signal pathway activated by volatiles from one PGPR strain is dependent on cyto-kinin activation for growth promotion and dependent on an ethylene-signaling pathway for induced pathogen resistance. This discovery provides new insight into the role of bacterial VOCs as initiators of both plant growth promotion and defense responses in plants.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.167.2-168
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• 2003

Anticancer drug resistance occasionally occurs in malignant hematologic diseases such as acute myelocytic leukemia (AML) treated with chemotherapy and is a major problem to complete remission. Malignant cells primarily induce intrinsic resistance to treatment of anticancer drug, but gradually obtain acquired resistance to cytotoxic activities of chemotherapy. In this study, we monitored the expression profiles of doxorubicin resistance-related genes in AML-2/DX100, a doxorubicin-resistant human acute myelocytic leukemia cell line. (omitted)

• YAKHAK HOEJI
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• v.30 no.6
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• pp.317-322
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• 1986

To clarify resistance mechanisms of lincosamide antibiotics, it was examined whether lincosamide antibiotics was able to induce high resistance to macrolide and lincosamide antibiotics against EMR-1 strain of Bacillus species. And it was also examined whether the inducible resistance was plasmid-mediated or chromosome-mediated. This strain was identified as Bacillus licheniformis by its morphological and physiological characteristics. The subinhibitory concentrations of lincomycin and clindamycin induced high resistance in the strain to lincosamide antibiotics, but not to macrolide antibiotics. The inducible resistance was not eliminated by treating the strain with ethidium bromide, and plasmid was not identified by the alkaline lysis method of plasmid preparation. These results indicate, therefore, that the inducible resistance to macrolide and lincosamide antibiotics in the strain may be chromosome-mediated, not plasmid-mediated.

• Animal cells and systems
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• v.7 no.3
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• pp.213-219
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• 2003

The response of plants to pathogens and wounding is dependent upon very sensitive perception mechanisms. Although genetic approaches have revealed a variety of resistance genes that activate common defense responses, defense-related proteins are not well characterized in plants. Therefore, we used a proteomic approach to determine which defense-related proteins are induced by salicylic acid (SA) and wounding in Chinese cabbage. We found that SA and wounding induce pathogenesis-related protein 1a (PR1a) at both protein and mRNA levels using proteomics and Northern blot analysis, respectively. This indicates that our proteomic approach is useful for identifying defense-related proteins. We also identified several other proteins that are induced by SA or wounding. Among the seven SA-induced proteins identified, four may be defense-related, including defense-related protein, phospholipase D (PLD), resistance protein RPS2 homolog, and L-ascorbate peroxidase. Out of the six wounding-induced proteins identified, three may be defense-related: heat shock cognate protein 70 (HSC70), polygalacturonase, and peroxidase P7. The precise functions of these proteins in plant defense responses await further study. However, identification of the defense-related proteins described in this study should allow us to better understand the mechanisms and signal transduction pathways involved in defense responses in Chinese cabbage.

• Molecules and Cells
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• v.25 no.1
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• pp.119-123
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• 2008

Pyrimidine antagonists including 5-Fluorouracil (5-FU) have been used in chemotherapy for cancer patients for over 40 years. 5-FU, especially, is a mainstay treatment for colorectal cancer. It is a pro-drug that is converted to the active drug via the nucleic acid biosynthetic pathway. The metabolites of 5-FU inhibit normal RNA and DNA function, and induce apoptosis of cancer cells. One of the major obstacles to successful chemotherapy is the resistance of cancer cells to anti-cancer drugs. Therefore, it is important to elucidate resistance mechanisms to improve the efficacy of chemotherapy. We have used C. elegans as a model system to investigate the mechanism of resistance to 5-FU, which induces germ cell death and inhibits larval development in C. elegans. We screened 5-FU resistant mutants no longer arrested as larvae by 5-FU. We obtained 18 mutants out of 72,000 F1 individuals screened, and mapped them into three complementation groups. We propose that C. elegans could be a useful model system for studying mechanisms of resistance to anti-cancer drugs.

• Journal of Nutrition and Health
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• v.37 no.10
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• pp.888-898
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• 2004

This study was designed to investigate the effects of 8-week resistance exercise by using dumbell on the body com-position, serum hormone profiles and feeding patterns in young and healthy female students with over 30% of body fat, aged 22 years in Masan, Korea. The subjects were all six, performed successfully the entire exercise-program. Anthropometry, serum lipid and neurohormone profiles of subjects were analyzed at 0, 4 and 8 weeks after exercise. And also their food and nutrient intakes were self-reported by 3-day record and food frequency questionnaire. Triceps skinfold-thickness of the subject students significantly reduced after the exercise to 46% less than before (p < 0.002) . The serum concentrations of leptin, insulin and catecholamine appeared to decrease steadily, but not significantly. Total protein in serum increased significantly (p<0.05), and Na (p<0.005), K (p<0.001) and Fe (p<0.058) concentrations increased remarkably within the normal range. The 8-week resistance exercise tended to induce fiber consumption (p<0.089) of subject students and changed the P/M/S ratio changed into the desirable way from 0.8 : 1 : 1 to 1 : 1 : 1, and that of n-6/n-3 PUPA from 11 : 1 to 6 : 1. After taking exercise, the intake frequency of cookies (p<0.058) and raymeun (p<0.085) decreased, but finally this feeding pattern returned to the way as before even though at marginal significance. Consequently the resistance exercise may induce the desirable changes of body fat and improve serum lipid profiles and feeding patterns in young obese females.

• Journal of Yeungnam Medical Science
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• v.29 no.2
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• pp.73-76
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• 2012

More and more children are becoming obese and overweight due to several factors that include a high energy density in the diet (a high fat intake) and low energy expenditure. Consequently childhood obesity is becoming a significant health problem. Fat tissue releases many cytokines such as resistin, tumor necrosis factor-${\alpha}$, leptin, interleukin-6. These adipocytokines induce obesity-related insulin resistance. Insulin resistance is a key component of obesity-related metabolic problems such as hypertension, type 2 diabetes mellitus, dyslipidemia, non-alcoholic steatohepatitis, acanthosis nigricans and polycystic ovarian syndrome. This review article focused on insulin resistance and its related metabolic diseases.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.216-224
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• 1996

Recently, Korea Highway Corporation has attemped to improve the highway safety in accordance with minimizing user's imconveniences. Currently, the Anti Skidding Pavement(ASP) has been introduced as a safety countermeasure on the safety frailty sections. In this study, a series of field evaluations on pavement skid resistance have been conducted on the skid frailty sections to analyze the effects and problems of the Anti Skidding Pavement (ASP), and to understand the behavior of pavement skid resistance due to pavement type, section characteristics, vehicles' speed and traffec volume. Test results show the Anti Skidding Pavement (ASP) has the effects to induce vehicles' speed reduction. However, there are no effects to increase skid resistance. According to these results, it is demanded to improve the applying method of current Anti Skidding Pavement (ASP) to devise an effective safety countermeasure for pavement skid, and to increase pavement skid resistance.

• Journal of Yeungnam Medical Science
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• v.34 no.1
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• pp.19-28
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• 2017

The incidence of type 2 diabetes mellitus and insulin resistance is growing rapidly. Multiple organs including the liver, skeletal muscle and adipose tissue control insulin sensitivity coordinately, but the mechanism of skeletal muscle insulin resistance has not yet been fully elucidated. However, there is a growing body of evidence that lipotoxicity induced by mitochondrial dysfunction in skeletal muscle is an important mediator of insulin resistance. However, some recent findings suggest that skeletal mitochondrial dysfunction generated by genetic manipulation is not always correlated with insulin resistance in animal models. A high fat diet can provoke insulin resistance despite a coordinate increase in skeletal muscle mitochondria, which implies that mitochondrial dysfunction is not mandatory in insulin resistance. Furthermore, incomplete fatty acid oxidation by excessive nutrition supply compared to mitochondrial demand can induce insulin resistance without preceding impairment of mitochondrial function. Taken together we suggested that skeletal muscle mitochondrial overloading, not mitochondrial dysfunction, plays a pivotal role in insulin resistance.