• Korean Journal of Microbiology
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• v.49 no.3
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• pp.228-236
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• 2013

Campylobacter jejuni is one of important food-borne pathogens causing human gastroenteritis. We isolated 42 strains of C. jejuni from diarrhea patients and 4 food-poisoning outbreaks in 2010, Gyeonggi-do. In this study, 42 strains were tested for genetic characteristics, the serotype distribution and antimicrobial resistant rate. The presence of hipO (100%), cdtB (100%), and mutated gyrA (95.2%) genes was detected in C. jejuni by polymerase chain reaction (PCR). Detection of mutated gyrA gene correlated with ciprofloxacin resistance. Forty isolates had mutated gyrA gene and were actually resistant to ciprofloxacin. Furthermore, comparing the gyrA DNA sequence data, ciprofloxacin-resistant isolates had a mutation of the DNA sequence from ACA (threonine) to ATA (isoleucine). But 41 strains (97.6%) of patient isolates were susceptible to erythromycin and azithromycin. A total of 35.7% among 42 C. jejuni isolates were identified into 4 different serotypes. The serotype distribution of C. jejuni strains were shown to be HS2(B), HS3(C), HS4(D), HS19(O). To investigate the genotypes of C. jejuni isolated in Gyeonggi province, repetitive sequence polymerase chain reaction (rep-PCR) analysis and SmaI-digested pulsed-filed gel electrophoresis (PFGE) profile analysis were performed. From the PFGE analysis of 42 C. jejuni strains, 12 clusters of PFGE profile were obtained. On the other hand, 11 clusters of rep-PCR profile were obtained from 42 strains of C. jejuni.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.428-436
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• 2016

The emergence of antibiotic-resistant bacteria has been increased and become a public health concern worldwide. Many bacterial infections can be sequentially treated with different types of antibiotics. Thus, this study was designed to evaluate the changes in survival, antibiotic susceptibility, mutant frequency, ${\beta}$-lactamase activity, biofilm formation, and gene expression in Klebsiella pneumoniae after exposure to sequential antibiotic treatments of ciprofloxacin and meropenem. Treatments include control (CON; no addition), 1/2 MIC ciprofloxacin addition (1/2CIP), 2 MIC ciprofloxacin addition (2CIP), initial 1/2 MIC ciprofloxacin addition followed by 1/2 MIC meropenem (8 h-incubation) and 2 MIC ciprofloxacin (16 h-incubation) (1/2CIP-1/2MER-2CIP), initial 1/2 MIC ciprofloxacin addition followed by 1/2 MIC meropenem (8 h-incubation) and 2 MIC meropenem (16 h-incubation) (1/2CIP-1/2MER-2MER), and initial 1/2 MIC ciprofloxacin addition followed by 2 MIC ciprofloxacin(8 h-incubation) and 2 MIC meropenem(16 h-incubation) (1/2CIP-2CIP-2MER). No growth of K. pneumoniae was observed for the 2CIP throughout the incubation period. The numbers of planktonic cells varied with the treatments (7~10 log CFU/ml), while those of biofilm cells were not significantly different among treatments after 24-h incubation, showing approximately 7 log CFU/ml. Among the sequential treatments, the least mutant frequency was observed at the 1/2CIP-1/2MER-2CIP (14%). Compared to the CON, 1/2CIP-2CIP-2MER decreased the sensitivity of K. pneumoniae to piperacillin, cefotaxime, and nalidixic acid. The highest ${\beta}$-lactamase activity was 22 nmol/min/ml for 1/2CIP-1/2MER-2CIP, while the least ${\beta}$-lactamase activity was 6 nmol/min/ml for 1/2CIP-2CIP-2MER. The relative expression levels of multidrug efflux pump-related genes (acrA, acrB, and ramA) were increased more than 2-fold in K. pneumoniae exposed to 1/2CIP-1/2MER-2MER and 1/2CIP-2CIP-2MER. The results suggest that the sequential antibiotic treatments could change the antibiotic resistance profiles in K. pneumoniae.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.4
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• pp.401-406
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• 2017

In this study, using the VITEK 2 system, 74 samples (22.6%) out of 327 specimens were identified by the growth of Enterococcosel media (EV6 agar) supplemented with $6{\mu}g/mL$ of vancomycin. Enterococcus faecium was identified as 55 strains (74.3%), Enterococcus casseliflavus as 2 strains (2.7%), Enterococcus avium as 1 strain (1.4%), and Enterococcus gallinarum as 16 strains (21.6%). Among the 55 phenotypes of Enterococcus faecium, 42 (76.4%), 9 (16.4%), and 4 strains (7.3%) showed the vanA, vanB, and vanC phenotype, respectively. The 16 strains of Enterococcus gallinarum and 2 strains of Enterococcus casseliflavus showed the vanC phenotype and the 1 strain of Enterococcus avium had the vanB phenotype. The one strain of Enterococcus faecium propagated only in EV4 and was susceptible to both vancomycin and teicoplanin according to the antimicrobial susceptibility test using the VITEK 2 system. The vancomycin resistance phenotype gene was not detected by PCR. A total of 327 specimens were cultured in Enterococcosel broth supplemented with $6{\mu}g/mL$ of vancomycin (EV6 broth), and 120 strains (36.7%) were isolated. These 120 strains were subjected to vancomycin resistant genotyping by a multiplex real-time polymerase chain reaction and 51 strains (42.5%) showed vanA; 5 strains (4.2%) showed vanA and vanC; and 18 strains (15%) showed vanC. Vancomycin resistance genotypes were not detected in the remaining 46 strains (38.3%).

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.295-301
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• 2004

Recently, the rapid increase and global spread of extended-spectrum $\beta-lactamase$ producing clinical isolates has become a serious problem. The incidence of extended-spectrum $\beta-lactamase$ producing clinical isolates of Escherichia coli in Korea and susceptibility to antimicrobial agents were investigated. Total 233 isolates of E. coli were obtained from urine from hospitalized patients in Guro hospital, Korea University in 2001. One hun­dred and eighty four isolates $(78.9\%)$ were resistant to ampicillin, 80 isolates $(34.3\%)$ were resistant to ceph­alothin, 93 isolates $(39.9\%)$ were resistant to gentamicin, and 64 isolates $(27.5\%)$ were resistant to norfloxacin. Among 233 isolates, 17 isolates $(7.3\%)$ were positive as determined by the double disk synergy test. When min­imal inhibitory concentrations were assayed with additional 6 antimicrobial agents, 13 isolates $(76.5\%)$ were multi-drug resistant to at least four different class antimicrobial agents. Extended-spectrum $\beta-lactamase$ were characterized with isoelectric focusing gel electrophoresis and DNA sequencing. They were TEM-1 in 5 iso­lates, TEM-15 in 1 isolate, TEM-20 in 1 isolate, TEM-52 in 4 isolates, TEM-1 and AmpC in 2 isolates, TEM-1 and OXA-30 in 1 isolate, TEM-1 and OXA-33 in 1 isolate, TEM-1, CTX-M-3, and AmpC in 1 isolate, but SHV was not detected. Antimicrobial resistance genes were transferred to animal isolate of E. coli (CCARM No. 1203) by the filter mating method. Extended spectrum $\beta-lactamase$ producers studied in the current study have low correlation to each other as determined by random amplified polymorphic DNA and pulsed field gel elec­trophoresis. This is a contradictory result from the general hypothesis that extended-spectrum $\beta-lactamase$ pro­ducers in one hospital is a result from a clonal spread.

• Proceedings of the Ginseng society Conference
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• 2007.12a
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• pp.57-58
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• 2007

Purpose: Ginseng is a well-known medical plant used in traditional Oriental medicine. Korean red ginseng (KRG) has been known to have potent biological activities such as radical scavenging, vasodilating, anti-tumor and anti-diabetic activities. However, the mechanism of the beneficial effects of KRG on diabetes is yet to be elucidated. The present study was designed to investigate the anti-diabetic effect and mechanism of KRG extract in C57BL/KsJ db/db mice. Methods: The db/db mice were randomly divided into six groups: diabetic control group (DC), red ginseng extract low dose group (RGL, 100 mg/kg), red ginseng extract high dose group (RGH, 200 mg/kg), metformin group (MET, 300 mg/kg), glipizide group (GPZ, 15 mg/kg) and pioglitazone group (PIO, 30 mg/kg), and treated with drugs once per day for 10 weeks. During the experiment, body weight and blood glucose levels were measured once every week. At the end of treatment, we measured Hemoglobin A1c (HbA1c), blood glucose, insulin, triglyceride (TG), adiponectin, leptin, non-esterified fatty acid (NEFA). Morphological analyses of liver, pancreas and white adipose tissue were done by histological observation through hematoxylin-eosin staining. Pancreatic islet insulin and glucagon levels were detected by double-immunofluorescence staining. To elucidate an action of mechanism of KRG, DNA microarray analyses were performed, and western blot and RT-PCR were conducted for validation. Results: Compared to the DC group mice, body weight gain of PIO treated group mice showed 15.2% increase, but the other group mice did not showed significant differences. Compared to the DC group, fasting blood glucose levels were decreased by 19.8% in RGL, 18.3% in RGH, 67.7% in MET, 52.3% in GPZ, 56.9% in PIO-treated group. With decreased plasma glucose levels, the insulin resistance index of the RGL-treated group was reduced by 27.7% compared to the DC group. Insulin resistance values for positive drugs were all markedly decreased by 80.8%, 41.1% and 68.9%, compared to that of DC group. HbA1c levels in RGL, RGH, MET, GPZ and PIO-treated groups were also decreased by 11.0%, 6.4%, 18.9%, 16.1% and 27.9% compared to that of DC group, and these figure revealed a similar trend shown in plasma glucose levels. Plasma TG and NEFA levels were decreased by 18.8% and 16.8%, respectively, and plasma adiponectin and leptin levels were increased by 20.6% and 12.1%, respectively, in the RGL-treated group compared to those in DC group. Histological analysis of the liver of mice treated with KRG revealed a significantly decreased number of lipid droplets compared to the DC group. The control mice exhibited definitive loss and degeneration of islet, whereas mice treated with KRG preserved islet architecture. Compared to the DC group mice, KRG resulted in significant reduction of adipocytes. From the pancreatic islet double-immunofluorescence staining, we observed KRG has increased insulin production, but decreased glucagon production. KRG treatment resulted in stimulation of AMP-activated protein kinase (AMPK) phosphorylation in the db/db mice liver. To elucidate mechanism of action of KRG extract, microarray analysis was conducted in the liver tissue of mice treated with KRG extract, and results suggest that red ginseng affects on hepatic expression of genes responsible for glycolysis, gluconeogenesis and fatty acid oxidation. In summary, multiple administration of KRG showed the hypoglycemic activity and improved glucose tolerance. In addition, KRG increased glucose utilization and improved insulin sensitivity through inhibition of lipogenesis and activation of fatty acid $\beta$-oxidation in the liver tissue. In view of our present data, we may suggest that KRG could provide a solid basis for the development of new anti-diabetic drug.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.59-59
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• 2015

Cryptococcus neoformans causes life-threatening meningoencephalitis in humans, but the treatment of cryptococcosis remains challenging. To develop novel therapeutic targets and approaches, signaling cascades controlling pathogenicity of C. neoformans have been extensively studied but the underlying biological regulatory circuits remain elusive, particularly due to the presence of an evolutionarily divergent set of transcription factors (TFs) in this basidiomycetous fungus. In this study, we constructed a high-quality of 322 signature-tagged gene deletion strains for 155 putative TF genes, which were previously predicted using the DNA-binding domain TF database (http://www.transcriptionfactor.org/). We tested in vivo and in vitro phenotypic traits under 32 distinct growth conditions using 322 TF gene deletion strains. At least one phenotypic trait was exhibited by 145 out of 155 TF mutants (93%) and approximately 85% of the TFs (132/155) have been functionally characterized for the first time in this study. Through high-coverage phenome analysis, we discovered myriad novel TFs that play critical roles in growth, differentiation, virulence-factor (melanin, capsule, and urease) formation, stress responses, antifungal drug resistance, and virulence. Large-scale virulence and infectivity assays in insect (Galleria mellonella) and mouse host models identified 34 novel TFs that are critical for pathogenicity. The genotypic and phenotypic data for each TF are available in the C. neoformans TF phenome database (http://tf.cryptococcus.org). In conclusion, our phenome-based functional analysis of the C. neoformans TF mutant library provides key insights into transcriptional networks of basidiomycetous fungi and ubiquitous human fungal pathogens.

• Journal of Plant Biotechnology
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• v.35 no.3
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• pp.169-176
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• 2008

Salicylic acid(SA) is a phytohormone that is related to plant defense mechanism. The SA accumulation is triggered by abiotic and biotic stresses. SA acts as a signal molecular compound mediating systemic acquired resistance and hypersensitive response in plant. Although the role of SA has been studied extensively, an understanding of the SA regulatory mechanism is still lacking in plants. In order to comprehend SA regulatory mechanism, we have been transformed with a SID2 promoter:GUS::LUC fusion construct into siz1-2 mutant and wild plant(Col-0). SIZ1 encodes SUMO E3 ligase and negatively regulates SA accumulation in plants. SID2(SALICYLIC ACID INDUCTION DEFICIENT2) is a crucial enzyme of SA biosynthesis. The Arabidopsis SID2 gene encodes isochorismate synthase(ICS) that controls SA level by conversion of chorismate to isochorismate. We compared the regulation of SID2 in wild-type and siz1-2 transgenic plants that express SID2 promoter:GUS::LUC constructs respectively. The expressions of $\beta$-GLUCURONIDASE and LUCIFERASE were higher in siz 1-2 transgenic plant without any stress treatment. SID2 promoter:GUS::LUC/siz1-2 transgenic plant will be used as a starting material for isolation of siz1-2 suppressor mutants and genes involved in SA-mediated stress signaling pathway.

• Journal of Plant Biotechnology
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• v.40 no.4
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• pp.210-216
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• 2013

Efficient regeneration methods and transformation system are a priority for successful application of genetic engineering to vegetative propagated plants such as grape (Vitis labrusca L.). This research is to establish shoot regeneration system from plant explants for 'Campbell Early', 'Tamnara', 'Heukgoosul', 'Heukbosek' using two types of plant growth regulators supplemented to medium. The highest adventitious shoot regeneration rate of 5% was achieved on a medium containing of Murashige and Skoog (MS) inorganic salts and Linsmaier and Skoog (LS) vitamins, 2 mg/L of TDZ and 0.1 mg/L of IBA. Leaf tissue of 'Campbell Early', was co-cultivated with Agrobacterium strains, LBA4404 containing the vector pBI121 carrying with CaMV 35S promoter, gus gene as reporter gene and resistance to kanamycin as selective agent, the other Agrobacterium strains, GV3101 containing the vector pB7 WG2D carrying with mPAP1-D gene. mPAP1-D is a regulatory genes of the anthocyanin biosynthetic pathway. 'Campbell Early' harboring mPAP1-D gene was readily able to be selected by red color due to anthocyanin accumulation in the transformed shoot. These results might be helpful for further studies to enhance the transformation efficiency in grape.

• Korean Journal of Poultry Science
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• v.43 no.3
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• pp.177-189
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• 2016

This study was conducted to verify the relationships between the expression values of stress-related markers and their production performances in 25 strains of Korean domestic chicken breeds. For stress response markers, the amount of telomeric DNA; expression levels of heat shock protein (HSP)-70, $HSP-90{\alpha}$, and $HSP-90{\beta}$; and comet scores were analyzed. Production performances were measured by the survival rate, body weights, days at first egg laying, egg weight and hen housed egg production. The results showed that the production traits and values of stress-related markers showed significant differences between strains. In general, the stress response of pure bred chickens with heavy weights was relatively high, while that of hybrid chickens with light weights was relatively low. The correlation coefficients between telomere contents and body weights showed that there were weak negative relationships. However, the correlations of telomere content with the survival rate and egg production were weakly positive after 20 weeks old. The expression levels of HSP genes and DNA damage rate (comet scores) were positively correlated to body weight, but were negatively correlated to the survival rate and egg production. The results implied that increasing body weight was associated with increasing HSPs expression and the DNA damage rate was associated with decreasing telomere content. In addition, increasing HSPs expression and the DNA damage rate decreased the survival rate and egg production, but the relationships with the telomere content was the reverse. Correlations among the stress-related markers showed that there were significant correlation coefficients between all of the marker values. HSPs expression was negatively correlated to the telomere content, while it was positively correlated to the DNA damage rate. There was a highly negative correlation between the telomere content and DNA damage rate. In conclusion, increasing the HSP values and DNA damage rate can promote telomere reduction, which led to a decrease in disease resistance and robustness of the chicken. Thus, increasing the stress response was verified to adversely affect the laying performance and viability of chickens.

• Korean Journal of Plant Resources
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• v.29 no.1
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• pp.1-10
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• 2016

Obesity is a pro-inflammatory state that contributes to the development of metabolic disorders such as hyperlipidemia, insulin resistance, type 2 diabetes, non-alcoholic fatty liver, and cardiovascular disease. In this study, we evaluated the inhibition of adipogenesis in 3T3-L1 cells and in high-fat diet (HFD)-induced obese mice by Peucedanum japonicum Thunberg L. water extract (PJT). Lipid accumulation measurement indicates that PJT markedly inhibited adipogenesis in a dose-dependent manner. RT-PCR results demonstrated that the mRNA expression of adipogenic transcription factors such as peroxisome proliferator-activated receptor-γ (PPARγ) and CCAAT/enhancer binding protein-α (C/EBPα) in 3T3-L1 cells were significantly down-regulated by PJT treatment. Oral administration of PJT (100, 300, and 500 ㎎/㎏, b.w/daily for 4 weeks) was conducted in high-fat diet induced obese mice and C57BL/6 mice. The PJT-administered group of HFD-induced mice had a lower body weight gain, along with decreased serum levels of glucose, triglycerides, and total cholesterol compared with the control mice, however, the HDL-cholesterol/total cholesterol ratio was increased. Furthermore, the elevated mRNA expression levels of adipogenesis related genes in the white adipose tissue of obese mice were significantly suppressed by PJT. These results indicate that PJT exhibits anti-obesity effects in obese mice by decreasing in serum lipid levels and lipogenesis related gene.