• Toxicological Research
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• 제13권1_2호
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• pp.71-78
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• 1997

The mutational effects of pentachlorophenol (PCP) on the hypoxanthine phosphoribosyl transf erase (hprt) locus in human T-cell were analysed by T-cell clonal assay in vitro. Cells were exposed for 24 hours at primary culture to 0~100 ppm (W/V) PCP in dimethyl sulfoxide. Treated cells were allowed at the same time to stimulate by phytohemagglutinin (PHA) and T-cell growth factor (TCGF) and then seeded in medium containing 6-thioguanine to select for hprt-negative routants. We have also defined the optimal condition for the determination of mutant frequency. The parameters investigated include survival counting, first and second subculture for clonal efficiency plating and mutant plating. Under the optimal conditions, mutant frequencies of high dose-treated cells were significantly higher than those of non-treated or low dose cells. The results indicated a clear dose-effect relationship and showed that mutant frequency in 50 ppm PCP treated cell was 4.31$\times$$10^{-5}$ (background, 8.32$\times$$10^{-6}$). Above data strongly suggest that hprt mutation assay can be used as a biomarker for the environmental risk assessment.

• Journal of Microbiology
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• 제44권3호
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• pp.336-343
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• 2006

We compared the antimicrobial resistance and clonal relationships among the community-acquired (CA) and hospital-acquired (HA) methicillin-resistant Staphylococcus aureus (MRSA) strains that were isolated from blood cultures in a university hospital over a 4-year period. A total of 131 MRSA isolates, including 28 CA-MRSA and 103 HA-MRSA strains, were identified; antimicrobial susceptibility testing indicated that the CA-MRSA isolates were more susceptible to erythromycin (21 % vs 6% ; P=0.02), clindamycin (46% vs 12%; P<0.01), ciprofloxacin (43% vs 11%; P<0.01), and gentamicin (43% vs 6%; P<0.01) than were the HA-MRSA isolates. Pulsed-field gel electrophoresis (PFGE) typing and antimicrobial resistance profiles separated the 20 CA-MRSA isolates into 14 and 10 different patterns, respectively, and the 53 HA-MRSA isolates were separated into 24 and 7 different patterns, respectively. Twenty-one (40%) of the 53 HA-MRSA isolates belonged to two predominant PFGE types, and most of them showed multi-drug resistant patterns. Four (20%) of the 20 CA-MRSA and 10 (19%) of the 53 HA-MRSA isolates fell into two common PFGE patterns, and each of them showed the same multi-drug resistant pattern. This study suggests that, although the CA-MRSA blood isolates showed diverse PFGE and antimicrobial resistance patterns, some of these isolates may have originated from the HA-MRSA strains.

• BMB Reports
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• 제54권7호
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• pp.374-379
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• 2021

Tetranectin (TN), an adipogenic serum protein, enhances adipocyte differentiation, however, its functional mechanism has yet to be elucidated. In the present study, we investigated the adipogenic function of TN by using medium containing TN-depleted fetal bovine serum (TN-del-FBS) and recombinant mouse TN (mTN). The adipocyte differentiation of 3T3-L1 cells was significantly enhanced by mTN supplementation essentially at differentiation induction, which indicated a potential role of the protein in the early differentiation phase. The adipogenic effect of mTN was more significant with insulin in the differentiation induction cocktail, implicating their close functional relationship. mTN enhanced not only the proliferation of growing cells, but also mitotic clonal expansion (MCE) that is a prerequisite for adipocyte differentiation in the early phase. Consistently, mTN increased the phosphorylation of ERK in the early phase of adipocyte differentiation. Results of this study demonstrate that the adipogenic function of mTN is mediated by enhancing MCE via ERK signaling.

• 한국양식학회지
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• 제19권2호
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• pp.99-108
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• 2006

Sex of the Nile tilapia Oreochromis niloticus is mainly determined by an XX/XY system. However, accumulating evidences suggest the existence of additional sex modifying factors including environmental, autosomal and parental influences. In order to investigate the possibility of parental effects on sex ratios of tilapia progenies, in this study, a series of crosses was carried out using gynogenetic clonal fish, neomales, normal males and females, and YY fish. Crosses between clonal XX male and clonal female have yielded only female progenies and no parental influences were observed. However, in the crosses between clonal males and normal females, female parents were significantly associated with the progeny sex ratios ($X^2$=20.046, 7 d.f., p<0.01). Progeny sex ratios from the crosses between neomales and normal females ($X^2$=60.491, 5 d.f and $X^2$=28.072, 2 d.f.) also showed significant association with female parents (P<0.001). The stability of progeny sex ratios from repeated spawns were confirmed by using 6 different parental pairs. In 16 crosses between normal males and normal females, sex ratios of progenies showed clear maternal influences, and further analysis of the results revealed a negative correlation ($r^2$=0.7718, p<0.05) between the sex ratios of progenies from two different males, indicating a strong paternal influence. No statistically significant relationship between survival rates and sex ratios of progenies was observed in any genotypic groups. Taken together, the influence of parental pairs on progeny sex ratios in this species is evident although the cause of this influence is not clear.

• Journal of Periodontal and Implant Science
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• 제25권3호
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• pp.487-496
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• 1995

Previous studies have demonstrated that not all A. actinomycetemcomitans produced significant level of leukotoxic factor and its leukotoxicity have associated with serotype and genetic variation. Our aim was to investigate on the interrelationship between serotype and leukotoxicity of an A. actinomycetemcomitans consisting of 13 clinically well characterized. Korean isolates and to evaluate if particular virulent clonal types of A. actinomycetemcomitans are associated with periodontal disease. For this study, 13 strains of A. actinomycetemcomitans from 6 patients with periodontal disease were isolated and identified by using a selective medium(tryptic soy agar supplemented with 10% serum, $75{\mu}g$ of bacitracin and $5{\mu}g$ of vancomycin per ml) in 10% C02 incubator for 3days with routine Gram staining, colony morphology and biochemical test..For serotyping, antisera were prepared from reference strains of 5 serotypes. (ATCC 29523,Y4, SUNY aB 67, IDH 781, IDH 1705) and then ammonium sulfate precipitation, immunoabsorption and indirect immunofluoroscent procedures were done. For analysis of leukotoxicity, sonic extract of A. actinomycetemcomitans exposed to PMN, and trypan blue was stained for counting the cell viability. Finally Southern blot analyses of genomic DNA digested with the restriction enzyme Tag I was done and the Southern blots were hybridized with the 530bp fragment, termed delta 530, originating from the ltx promoter of strain 652 and deleted from strain JP2. Also ltxA-3.1 and SC2 probe from strain JP2 were hybridized with genomic DNA fragments. Results reveal that strains isolated showed approximately equal proportions of 3 serotypes(b, d, e) and serotype b was not detected. 2 patients harbored 2 different serotypes in the same disease site. The prevalence of leukotoxic strain was 23% and there was no relationship between serotype, leukotoxicity and clinical observations. Especially virulent clonal types of Actinobacillus actinomycetemcomitan (JP2 strain) could not found. Further studies are necessary on the genetic polymorphism of leukotoxin and its relations to clinical status.

• BMB Reports
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• 제51권10호
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• pp.481-483
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• 2018

Glioblastoma (GBM) is the most common and aggressive form of human adult brain malignancy. The identification of the cell of origin harboring cancer-driver mutations is the fundamental issue for understanding the nature of GBM and developing the effective therapeutic target. It has been a long-term hypothesis that neural stem cells in the subventricular zone (SVZ) might be the origin-of-cells in human glioblastoma since they are known to have life-long proliferative activity and acquire somatic mutations. However, the cell of origin for GBM remains controversial due to lack of direct evidence thereof in human GBM. Our recent study using various sequencing techniques in triple matched samples such as tumor-free SVZ, tumor, and normal tissues from human patients identified the clonal relationship of driver mutations between GBM and tumor-free SVZ harboring neural stem cells (NSCs). Tumor-free SVZ tissue away from the tumor contained low-level GBM driver mutations (as low as 1% allelic frequency) that were found in the dominant clones in its matching tumors. Moreover, via single-cell sequencing and microdissection, it was discovered that astrocyte-like NSCs accumulating driver mutations evolved into GBM with clonal expansion. Furthermore, mutagenesis of cancer-driving genes of NSCs in mice leads to migration of mutant cells from SVZ to distant brain and development of high-grade glioma through the aberrant growth of oligodendrocyte precursor lineage. Altogether, the present study provides the first direct evidence that NSCs in human SVZ is the cell of origin that develops the driver mutations of GBM.

• Journal of Microbiology
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• 제44권4호
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• pp.453-456
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• 2006

16 chicken isolates and four clinical isolates of VanB-vanA incongruent vancomycinresistant Enterococcus faecium strains without vanS were isolated in 1999. Pulsed-field gel electrophoresis revealed only a peripheral relationship between the chicken isolates and clinical isolates, but suggested clonal spread in the chicken isolates.

• 대한두경부종양학회지
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• 제9권1호
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• pp.25-32
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• 1993

저자들은 배양에 성공한 결절성 갑상선종 2예와 유두성 갑상선암 2예에서 염색체 이상을 찾아내어 이러한 이상들이 서로 연관을 갖는지 여부를 연구하고자 본 실험을 시행하였다. 결절성 갑상선종의 염색체 형태는 매우 다양하게 나타나면서도 2예 모두가 특이적인 염색체 이상은 보이지 않았다. 제 1 예 : modal 염색체 슷자는 42에서 46범위 내였고 염색체 8, 19, 21, 22는 빈번한 결손을 보였다. 51개 분석 세포들 중에 9가지 구조적 변성이 관찰되었으나 집단 염색체 변화는 없었다. 제 2 예 : modal 염색체 수는 43이었고, 염색체 17과 19는 흔한 결손을 나타내었다. 이 두 결절성 갑상선종의 세포유전학적 특성은 저이배체(hypodiploidy)와 매우 다양한 염색체 양상을 나타내었다. 유두성 갑상선암에 대한 분석 결과는 다음과 같다. 제 3 예 : 다소의 숫적, 구조적 염색체 변화가 관찰되었으나 특이적인 염색체 이상은 찾아볼 수 없었다. 제 4 예 : 염색체 양상이 del(11)(q23)의 집단 염색체 변화를 수반하는 매우 다양한 이질적인 양상을 나타내었다. 유두성 갑상선암의 del(11)(q23) 염색체 변화는 이미 Eva Olah등이 1989년 보고한 바 있다. 아마도 갑상선에서 유두성 갑상선암의 암화과정에 11q 결손이 중요한 역할을 할 것으로 추정된다. 이상의 결과에 따르면 유두성 갑상선암과 결절성 갑상선종 둘 다 염색체 이상을 나타냈지만 양자간의 염색체의 특이적인 상관 관계를 발견할 수 없었다.

• The Plant Pathology Journal
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• 제33권1호
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• pp.21-33
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• 2017

Citrus blast caused by bacterium Pseudomonas syringae is a very important disease of citrus occuring in many areas of the world, but with few data about genetic structure of the pathogen involved. Considering the above fact, this study reports genetic characterization of 43 P. syringae isolates obtained from plant tissue displaying citrus blast symptoms on mandarin (Citrus reticulata) in Montenegro, using multilocus sequence analysis of gyrB, rpoD, and gap1 gene sequences. Gene sequences from a collection of 54 reference pathotype strains of P. syringae from the Plant Associated and Environmental Microbes Database (PAMDB) was used to establish a genetic relationship with our isolates obtained from mandarin. Phylogenetic analyses of gyrB, rpoD, and gap1 gene sequences showed that P. syringae pv. syringae causes citrus blast in mandarin in Montenegro, and belongs to genomospecies 1. Genetic homogeneity of isolates suggested that the Montenegrian population might be clonal which indicates a possible common source of infection. These findings may assist in further epidemiological studies of this pathogen and for determining mandarin breeding strategies for P. syringae control.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.899-903
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• 2005

Two infectious species of Streptococcosis pathogens were detected by multiplex PCR assay. Detection rates of Streptococcus iniae and S. parauberis could reach 44.9% and 55.1% respectively for one year during 2004 to 2005 in Jeju island. These findings showed that S. parauberis strains were important pathogen with streptococcosis of olive flounder in Jeju island. These findings showed that S. parauberis strains were important pathogen with streptococcosis of olive flounder in Jeiu island. In the present study we have investigated the interspecific relationship of all Jeju area of S. parauberis by RAPD analysis. Represent strains divided to four groups by RAPD fingerprints. The important differences observed between the olive flounder isolates suggest that they could constitute a well-differentiated group or a separate clonal line within this bacterial species. Though, serological research of S. parauberis strains in Jeju island not exist yet. These strains doing the serological evolution.