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Hae Woon Choi,Ha Young Song,Dal Hoe Koo,Jae Wook Bang,Yoon Kang Hur 한국유전학회 2007 Genes & Genomics Vol.29 No.4
In order to identify and discriminate a medicinal herb, A. acutiloba, from closely related species, species-specific repetitive DNAs have been cloned and characterized by Southern blotting and FISH (fluorescence in situ hybridization). From restriction enzyme analysis, tandemly repeated sequences specific for A. acutiloba (AaTRS) were obtained from an EcoRI digestion. The EcoRI monomers were 154-159 bp long, 60-66% of A+T residues and did not show any similarity to the known plant repetitive DNAs. Its repeats are organized in head-to-tail orientation. Southern blot analysis of genomic DNA digested with the same enzyme showed the existence of a ladder pattern only in A. acutiloba, indicating that the repetitive DNA is arrayed in tandem. In FISH experiment, the AaTRS was localized on the telomeric regions of somatic metaphase chromosomes in A. acutiloba. Although seven monomers revealed high sequence variation as the typical features of eukaryotic repetitive DNA, SCAR (sequence characterized amplified region) markers generated from their sequence information could discriminate A. acutiloba from two other species.
Xylitol 생산에 최적화된 xylose reductase (GRE3)의 분비발현 시스템
정회명(Hoe-Myung Jung),김재운(Jae-Woon Kim),김연희(Yeon-Hee Kim) 한국생명과학회 2016 생명과학회지 Vol.26 No.12
Xylitol은 식품 및 의료산업에서 이용가치가 높은 물질로, lignocellulosic biomass인 xylose의 환원으로부터 생산되며, 대부분 유전적으로 안전한 Saccharomyces cerevisiae 균주를 사용하여 생산되고 있다. 따라서 본 연구에서는 S. cerevisiae에서 xylitol을 효율적으로 생산하기 위해 xylose reductase를 code하는 GRE3 (YHT104W)유전자의 발현시스템을 구축하여, xylose reductase의 분비생산 및 xylitol 생산성을 조사하고자 하였다. 먼저 GRE3 유전자의 발현에 적합한 promoter의 선별을 위해 GAL10 promoter와 ADH1 promoter 하류에 각각 mating factor α (MFα) signal sequence와 GRE3 유전자를 가진 pGMF-GRE3와 pAMF-GRE3 plasmid를 구축하였다. 각각의 plasmid는 S. cerevisiae SEY2102△trp1균주에 형질전환되었고, SEY2102△trp1/pGMF-GRE3와 SEY2102△trp1/pAMF-GRE3 형질전환주가 선별되었다. 그 중 SEY2102△trp1/pGMF-GRE3 균주에서 NADPH를 cofactor로 사용했을 때 0.34 unit/mg-protein의 xylose reductase 활성(total activity)을 보였고, ADH1 promoter를 가진 SEY2102△trp1/pAMF-GRE3 균주에 비해 1.5배 높은 활성증가를 확인 할 수 있었다. 또한 두 균주에서 모두 91%의 분비효율을 보여 대부분의 재조합 xylose reductase가 세포 밖으로 효율적으로 발현 분비되었음을 알 수 있었다. SEY2102△trp1/pGMF-GRE3 균주를 사용한 baffled flask 배양에서 xylitol 생산량을 조사해 본 결과, 20 g/l의 xylose로부터 12.1 g/l의 xylitol을 생산하였고, 소모된 xylose의 약 83%정도가 xylitol로 환원되었음을 알 수 있었다. Xylitol is widely used in the food and medical industry. It is produced by the reduction of xylose (lignocellulosic biomass) in the Saccharomyces cerevisiae strain, which is considered genetically safe. In this study, the expression system of the GRE3 (YHR104W) gene that encodes xylose reductase was constructed to efficiently produce xylitol in the S. cerevisiae strain, and the secretory production of xylose reductase was investigated. To select a suitable promoter for the expression of the GRE3 gene, pGMF-GRE3 and pAMF-GRE3 plasmid with GAL10 promoter and ADH1 promoter, respectively, were constructed. The mating factor α (MFα) signal sequence was also connected to each promoter for secretory production. Each plasmid was transformed into S. cerevisiae SEY2102△trp1, and SEY2102△ trp1/pGMF- GRE3 and SEY2102△trp1/pAMF-GRE3 transformants were selected. In the SEY2102△ trp1/pGMF-GRE3 strain, the total activity of xylose reductase reached 0.34 unit/mg-protein when NADPH was used as a cofactor; this activity was 1.5 fold higher than that in SEY2102△trp1/pAMF-GRE3 with ADH1 as the promoter. The secretion efficiency was 91% in both strains, indicating that most of the recombinant xylose reductase was efficiently secreted in the extracellular fraction. In a baffled flask culture of the SEY2102△trp1/pGMF-GRE3 strain, 12.1 g/l of xylitol was produced from 20 g/l of xylose, and ~83% of the consumed xylose was reduced to xylitol.
Eun-Hoe Goo,Sun-Ju Kim,Kyung-Rae Dong,Kwang-Choul Kim,Woon-Kwan Chung 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.5
The purpose of this study is to evaluate the image quality in delineation of the portal venous systems with two different methods, breath-hold and non-breath-hold by using the 3D FLASH sequence. We used a 1.5 T system to obtain magnetic resonance(MR)images. Arterial and portal phase 3D FLASH images were obtained with breath-hold after a bolus injection of GD-DOTA. The detection of PVS on the MR angiograms was classified into three grades. First, the angiograms of the breath-hold method showed well the portal vein, the splenic vein and the superior mesenteric vein systems in 13 of 15 patients (86%) and the inferior mesenteric vein system in 6 of 15 patients (40%), Second, MR angiograms of the non-breath-hold method demonstrated the PVS and the SMV in 12 of 15 patients (80%) and the IMV in 5 of 15 patients (33%). Our study showed contrast-enhanced 3D FLASH MR angiography, together with the breath-hold technique, may provide reliable and accurate information on the portal venous system.
Effect of Driver's Cognitive Distraction on Driver's Physiological State and Driving Performance
Jun-Hoe Kim,Woon-Sung Lee 대한인간공학회 2012 大韓人間工學會誌 Vol.31 No.2
Objective: The aim of this study is to investigate effect of driver"s cognitive distraction on driver"s physiological state and driving performance, and then to determine parameters appropriate for detecting the cognitive distraction. Background: Driver distraction is a major cause of traffic accidents and poses a serious threat to traffic safety due to ever increasing use of in-vehicle information systems and mobile phones during driving. Cognitive distraction, among four different types of distractions, prevents a driver from processing traffic information correctly and adapting to change in surround vehicle behavior in time. However, the cognitive distraction is more difficult to detect because it normally does not involve significant change in driver behavior. Method: A full-scale driving simulator was used to create virtual driving environment and situations. Participants in the experiment drove the driving simulator in three different conditions: attentive driving with no secondary task, driving and conducting secondary task of adding numbers, and driving and conducting secondary task of conversing with an experimenter. Parameters related with driver"s physiological state and driving performance were measured and analyzed for their change. Results: The experiment results show that driver"s cognitive distraction, induced by secondary task of addition and conversation during driving, increased driver"s cognitive workload, and indeed brought change in driver"s physiological state and degraded driving performance. Conclusion: The galvanic skin response, pupil size, steering reversal rate, and driver reaction time are shown to be statistically significant for detecting cognitive distraction. The appropriate combination of these parameters will be used to detect the cognitive distraction and estimate risk of traffic accidents in real-time for a driver distraction warning system.