• Applied Biological Chemistry
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• 제50권4호
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• pp.262-267
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• 2007

토양에는 생존하지만 현 기술로는 배양이 불가능한 미생물로부터 천연 항생제를 탐색하기 위해 한국 토양 DNA 단편들을 가진 cosmid library을 대장균에서 제작하였고 약6만개의 clone들을 대상으로 항세균 활성을 보여주는 YS92B를 최종 선발하였다. YS92B클론 배양액의 ethyl acetate추출액은 다양한 병원성 세균의 성장을 in vitro에서 강력히 저해하였다(Listeria monocytogenes, Bacillus subtilis, Pseudomonas syringae, Xanthomonas campestris pv. oryzae, Staphylococcus epidemis). 이 항균활성의 주 물질인 YS92B-VII는 ethyl acetate추출, Sephadex LH20 column chromatography와 HPLC(High Performance Liquid Chromatography)에 의해 순차적으로 분리하였으며 이 과정에서 주 활성물질은 각 피크를 항균검정으로 추적하여 최종 정제하였다. 이 물질은 NMR(Nuclear Magnetic Resornance)에 의한 구조 분석 결과에서 탄소 12개의 포화지방산인 lauric acid가 tyrosine에 결합된 N-lauroyl tyrosine임을 최종 확인하였다. 따라서 본 보고는 한국 토양에서 유래한 고유의 N-acyl amino acid synthase(NAS)유전자가 대장균에 발현되어 생산되는 N-acyl amino acid tyrosine의 특성을 밝히는 것이다.

• Journal of Microbiology
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• 제44권4호
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• pp.423-431
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• 2006

Among 53 Acinetobacter baumannii isolates collected in 2004, nine imipenem-resistant isolates were obtained from clinical specimens taken from patients hospitalized in Busan, Korea. Nine carbapenemase-producing isolates were further investigated in order to determine the mechanisms underlying resistance. These isolates were then analyzed via antibiotic susceptibility testing, microbiological tests of carbapenemase activity, pI determination, transconjugation test, enterobacterial repetitive consensus (ERIC)-PCR, and DNA sequencing. One outbreak involved seven cases of infection by A. baumannii producing OXA-23 ${\beta}-lactamase$, and was found to have been caused by a single ERIC-PCR clone. During the study period, the other outbreak involved two cases of infection by A. baumannii producing IMP-1 ${\beta}-lactamase$. The two clones, one from each of the outbreaks, were characterized via a modified cloverleaf synergy test and an EDTA-disk synergy test. The isoelectric focusing of the crude bacterial extracts detected nitrocefin-positive bands with pI values of 6.65 (OXA-23) and 9.0 (IMP-1). The PCR amplification and characterization of the amplicons via direct sequencing showed that the clonal isolates harbored $bla_{IMP-1}$ or $bla_{oxA-23}$ determinants. The two clones were characterized by a multidrug resistance phenotype that remained unaltered throughout the outbreak. This resistance encompassed penicillins, extended-spectrum cephalosporins, carbapenems, monobactams, and aminoglycosides. These results appear to show that the imipenem resistance observed among nine Korean A. baumannii isolates could be attributed to the spread of an IMP-lor OXA-23-producing clone. Our microbiological test of carbapenemase activity is a simple method for the screening of clinical isolates producing class D carbapenemase and/or class B $metallo-{\beta}-lactamase$, in order both to determine their clinical impact and to prevent further spread.

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2003년도 춘계학술대회
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• pp.56-56
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• 2003

• 한국해양학회지:바다
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• 제17권3호
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• pp.160-180
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• 2012

본 연구는 메타게놈 분석법을 기초로 낙동강 하류 담수 환경의 물금과 기수 환경의 을숙도대교 정점에서 채수된 환경 시료내의 진핵 플랑크톤 종다양성 및 군집 구조를 비교 분석하고자 하였다. 수환경 시료에서 추출된 DNA에 대한 environmental Polymerase Chain Reaction(PCR)을 수행하여 18S rDNA 클론라이브러리를 구축하였고, colony PCR, PCR-Restriction Fragment Length Polymorphism(RFLP), 염기서열 결정 및 유사도 분석을 통하여 종다양성을 분석하였다. 물금 및 을숙도대교 정점에서 338개의 클론들을 분석하였고(170 clones, 물금; 168 clones, 을숙도대교), 그 결과 총 74개의 phylotype을 발굴하였다(49개, 물금; 25개, 을숙도대교). 발굴된 phylotype에 대한 계통 분석 결과, Stramenopiles, Cryptophyta, Viridiplantae, Alveolata, Rhizaria, Metazoa 및 Fungi 등의 분류군에 속하는 다양한 생물종이 발굴되었으며, 국내 미기록종 및 신종 후보 가능 생물종과 속(genus)이상의 새로운 분류학적 처리가 필요한 생물종의 존재를 확인하였다. 특히 Stramenopiles의 Pirsonia 및 Alveolata의 Perkinsea에 속하는 phylotypes 등 국내 미기록 생물종을 포함한 숨은 종다양성(cryptic species diversity)의 발굴은 분자모니터링 기법이 낙동강 하구역 수생태계 변화 모니터링을 위한 새로운 유용한 생물학적 정보를 제공할 수 있음을 제시하고 있다.

• Molecular & Cellular Toxicology
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• 제2권2호
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• pp.75-80
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• 2006

Biomarkers identify various stages and interactions on the pathway from exposure to disease. The three categories of biomarkers are those measuring susceptibility, exposure and effect. Susceptibility biomarkers are identifiable genetic variations affecting absorption, metabolism or response to environmental agents. Biomarkers of exposure indicate the amount of a foreign compound that is absorbed into the body. Biological measurements performed on human tissues are vastly expanding the capabilities of classical epidemiology, which has relied primarily on estimates of human exposure derived form chemical levels in the air, water, and other exposure routes. Biomarkers of exposure indicate the amount of a foreign compound that is absorbed into the body. Biological measurements performed on human tissues are vastly expanding the capabilities of classical epidemiology, which has relied primarily on estimates of human exposure derived form chemical levels in the air, water, and other exposure routes. The biomarker response is typical of chemical pollution by specific classes of compound, such as (i) heavy metals (mercury, cadmium, lead, zinc), responsible for the induction of metallothionein synthesis, and (ii) organochlorinated pollutants (PCBs, dioxins, DDT congeners) and polycyclic aromatic hydrocarbons (PAHs), which induce the mixed function oxygenase (MFO) involved in their bio transformations and elimination. Currently genomic researches are developed in human cDNA clone subarrays oriented toward the expression of genes involved in responses to xenobiotic metabolizing enzymes, cell cycle components, oncogenes, tumor suppressor genes, DNA repair genes, estrogen-responsive genes, oxidative stress genes, and genes known to be involved in apoptotic cell death. Several research laboratories in Korea for kicking off these Environmental Genomics were summarized.

• Journal of Microbiology and Biotechnology
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• 제26권1호
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• pp.99-109
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• 2016

We investigated the relation between the presence of geosmin in water and the bacterial community structure within the granular activated carbon (GAC) system of water treatment plants in South Korea. GAC samples were collected in May and August of 2014 at three water treatment plants (Sungnam, Koyang, and Yeoncho in Korea). Dissolved organic carbon and geosmin were analyzed before and after GAC treatment. Geosmin was found in raw water from Sungnam and Koyang water treatment plants but not in that from Yeoncho water treatment plant. Interestingly, but not surprisingly, the 16S rRNA clone library indicated that the bacterial communities from the Sungnam and Koyang GAC systems were closely related to geosmin-degrading bacteria. Based on the phylogenetic tree and multidimensional scaling plot, bacterial clones from GAC under the influence of geosmin were clustered with Variovorax paradoxus strain DB 9b and Comamonas sp. DB mg. In other words, the presence of geosmin in water might have inevitably contributed to the growth of geosmin degraders within the respective GAC system.

• Journal of Plant Biotechnology
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• 제35권2호
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• pp.95-100
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• 2008

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a main enzyme in the glycolytic pathway, is involved in cellular energy production and regarded as a housekeeping gene. Previously, cytosolic GAPDH was selected as the most significantly abundant gene in EST library of sweetpotato suspension cells. In this study, a full-length of cDNA clone (IbGAPDH) encoding GAPDH was isolated from suspension-cultured cells of sweetpotato (Ipomoea babatas), and its expression was investigated with a view to understanding the physiological function of GAPDH in relation to environmental stresses. IbGAPDH encoded a 36.9 kDa polypeptide consisting of 337 amino acids. When the deduced amino acid of IbGAPDH was compared with other higher plants, IbGAPDH showed high homology with cytosolic GAPDH. The mRNA level of IbGAPDH significantly increased under environmental stresses, such as $H_2O_2$, MV and cold treatments. Among them, the transcript level of IbGAPDH gene was the highest under cold stress. Further investigation of the transcription level under $10^{\circ}C$ or $15^{\circ}C$ was performed with different tissues of sweetpotato. The transcription of IbGAPDH was increased by cold stress with tissue-specificity, moreover, showed different patterns according to temperature.

• Journal of Forest and Environmental Science
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• 제36권4호
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• pp.259-266
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• 2020

Poplar trees from the Salicaceae family over the years have been utilized for various reasons which include prevention of deforestation as well as phytoremediation. This study aims to determine the optimal pre-treatment and soil conditions required for propagation of poplar cuttings for increased initial adaptability and survival rate. Five poplar clones (Hanan, 110, 107, DN-34, 52-225) were selected for IBA, soil composition treatments on propagation. IBA pre-treatment of cuttings were utilized 0, 10, and 100 mg l-1 concentrations. Soil compositions were amended with TKS-2+perlite 2:1 (v:v) and sandy clay loam mixed with artificial soil. According to the greenhouse results 10 mg l-1 of IBA showed a significant increase in plant height whereas 100 mg l-1 inhibited plant growth except in clone 110. Soil composition severely affected root growth and hence overall growth of the clones. Sandy clay loam soil had poor to stunted growth compared to TKS-2+perlite.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권6호
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• pp.510-515
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• 2006

The putative EPA synthesis gene cluster was mined from the entire genome sequence of Shewanella oneidensis MR-1. The gene cluster encodes a PKS-like pathway that consists of six open reading frames (ORFs): ORFSO1602 (multi-domain beta-ketoacyl synthase, KS-MAT-4ACPs-KR), ORFSO1600 (acyl transferase, AT), ORFSO1599 (multi-domain beta-ketoacyl synthase, KS-CLF-DH-DH), ORFSO1597 (enoyl reductase, ER), ORFSO1604 (phosphopentetheine transferase, PPT), and ORFSO1603 (transcriptional regulator). In order to prove involvement of the PKS-like machinery in EPA synthesis, a 20.195-kb DNA fragment containing the genes was amplified from S. oneidensis MR-1 by the long-PCR method. Its identity was confirmed by the methods of restriction enzyme site mapping and nested PCR of internal genes orfSO1597 and orfSO1604. The DNA fragment was cloned into Escherichia coli using cosmid vector SuperCos1 to form pCosEPA. Synthesis of EPA was observed in four E. coli clones harboring pCosEPA, of which the maximum yield was 0.689% of the total fatty acids in a clone designated 9704-23. The production yield of EPA in the E. coli clone was affected by cultivation temperature, showing maximum yield at $20^{\circ}C$ and no production at $30^{\circ}C$ or higher. In addition, production yield was inversely proportional to glucose concentration of the cultivation medium. From the above results, it was concluded that the PKS-like modules catalyze the synthesis of EPA. The synthetic process appears to be subject to regulatory mechanisms triggered by various environmental factors. This most likely occurs via the control of gene expression, protein stability, or enzyme activity.

• Journal of Forest and Environmental Science
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• 제37권4호
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• pp.309-314
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• 2021

This study aimed to enhance seed productivity and secure genetic resources for Pinus densiflora for. multicaulis. We analyzed the characteristics of cone and seed generated by control pollination between Pinus densiflora (PD) and Pinus densiflora for. multicaulis (PDM). The highest number of cone scales (63.0) was obtained from the self-pollinated (sp) PDM clone B (PDM-sp-B), whereas the lowest number of cone scales (44.7) was obtained from two combinations designated as PDM-A×PD-075 and PDM-A×PD-0111. Both female parents of the hybrids were PDM-A. The highest seed production capacity (80.8) was obtained from the open-pollinated (op) PDM clone B (PDM-op-B). The seed potentials of PDM-B×PD-0111, PDM-op-A, and PDM-sp-B were 67.4, 66.5, and 63.1, respectively. The highest number of fertile scales (41.5) was obtained from PDM-op-B, and the lowest number of fertile scales (28.8) was obtained from PDM-A×PD-075. The total number of aborted ovules and 1st aborted ovules was not statistically significant in the mating design. The cross combination of PDM-B×PD-0111 had the highest number (34.8) of filled seeds and the lowest number of 2nd aborted ovules (5.2) and empty seeds (9). PDM-op-B had the highest number of developed seeds (47.6), although the number of empty seeds was the highest (41.2). Therefore, we conclude that the mating design of PDM-B×PD-0111 is useful for future breeding programs to improve seed yield of PDM. Our results showed that there was a strong correlation between the following two parameter pairs: number of scales and number of fertile scales, and the number of fertility scales and seeds potential (r=0.89 and r=0.84, respectively; both p<0.01).