11:10-12:00, Rm 103

MicrobiologyG-17-01Fatty acids increase a liver inflammation via HBx stabilization byreactive oxygen species and Ca2+ signalingHyun Kook Cho, Hye-Young Kim, So Young Kim and Jaehun CheongDepartment of Molecular Biology, College of Natural Science, Pusan National University, Busan609-735, KoreaFatty acids contribute to many cellular functions that protein modification and expressionof genes for lipid homeostasis. However, excessive fatty acids induce lipotoxic cellularinjury including ER stress, inflammation, and apoptosis. This study also describes theeffect of fatty acids on HBx protein stability and HBx-induced inflammation. Fatty acidsenhance generation of cellular reactive oxygen species (ROS) and efflux of Ca2+ fromER. Fatty acid-induced ROS and intracellular Ca2+ increase HBx stability and that isconfirmed by using antioxidant N-acetylcysteine (NAC) and calcium chelator BAPTA-AM,respectively. Focal adhesion kinase (FAK) interacts with HBx and the interaction isenhanced by fatty acids treatment. In addition, fatty acid-induced HBx protein stabilizationand inflammatory genes expression are abolished by knock-down of FAK gene,suggesting that those are mediated by FAK. In conclusion, fatty acids show synergiceffects on HBx-induced inflammatory genes expression through HBx protein stabilization.These findings provide important information to understand the HBV-inducedpathogenesis.G-17-04Antifungal activity of ethanol extract and its fractions from Hostacapitata on human pathogenic and airborne fungiJi Ho Yun, Saet Byoul Lee, Hee Ju Lee, Chul Young Kim and Chu Won NhoFunctional Food Center, Korea Institute of Science and Technology, Gangneung, Gangwon-do 210-340, KoreaHuman pathogenic fungi usually induce pathogenic diseases through infection to body.Especially, the airborn fungi, their spores are claimed to cause many diseases such asallergic, respiratory diseases, and inflammation. In this study, we investigated theantifungal activity of extract and its fractions from Hosta capitata against humanpathogenic fungi including C. albicans and S.cerevisiae as well as airborne fungi such asC. cladosporeoides. We found that the extract and BuOH fraction showed potentantifungal activity against three fungi tested by both agar diffusion method and minimuminhibitory concentration assay. Moreover, this extract and BuOH fraction showed theinhibition of dimorphic transition in C. albicans which is a key mechanism in thepathogenesis of host infection, was confirmed by fetal bovine serum inducing assay. Toelucidate the mode of action for growth inhibition against C. albicans and S.cerevisiae, weperformed a flow cytometric cell cycle analysis and found cell cycle arrest by either theextract or BuOH treatment. Taken together, Hosta capitata extract and its BuOH fractionexert the antifungal activation on human pathogenic and airborne fungi, suggesting agood candidate for potent natural antifungal agent.G-17-02Regulatory mechanism of hepatic six transmembrane protein of prostate2 (STAMP2) in HBx-associated metabolic disordersHye-Young Kim, Hyun-Kook Cho, So-Young Kim and Jae-Hun CheongDepartment of Molecular Biology, College of Natural Sciences, Pusan National University, Busan609-735, KoreaThe six transmembrane protein of prostate 2 (STAMP2) was recently identified asregulatory factor that links inflammatory and diet-derived signals to host systemicmetabolism. Because Hepatitis B virus X protein (HBx) is a multifunctional viral regulatorwhich modulates a variety of host processes including inflammatory responses andseveral metabolic disorders in the liver, it was assessed whether HBx physically interactswith STAMP2. The STAMP2 physically interacted with C-termainal of HBx, result indecreases the protein stability of HBx, leading to counteract the HBx-induced hepaticmetabolic disorders, including lipid accumulation and insulin resistance. In particular,STAMP2 is able to suppress the HBx-mediated expression and transcriptional activity oflipogenic- (ACC1, FAS, SCD1, SREBP1) and adipogenic- (aP2, PPARγ) genes therebycontrolling the hepatic lipid accumulation. Furthermore, STAMP2 prevents HBx-induceddegradation of IRS1 protein, result in sensitizing hepatic insulin signaling, leading torestore the impaired insulin- inhibitory expression of gluconeogenic genes, PEPCK andG6Pase. These results point to a regulatory mechanism of host defense system inresponse to HBx-mediated metabolic disorders.G-17-05Cloning of Plasmodium falciparum Subtilase and Selection of a SuitableVector*Suk-Yul Jung and Chang-Eun ParkDepartment of Biomedical Laboratory Science, Namseoul University, Cheonan, Chungnam 331-707, KoreaMalaria infects human and causes severe anemia, fever, cerebral infection, etc. A specifictype of merozoite circulates into a liver and destroys its function. In both humans andmice, liver injury is involved after parasite entry, persisting to the erythrocyte stage afterinfection with the fatal strains Plasmodium falciparum (Pf). Pf subtilisin-like protease 2(subtilase, Sub2) is an essential integral membrane serine protease in Pf. It functions inthe shedding of the ectodomain components of two surface proteins, membrane surfaceprotein 1 (MSP1) and apical membrane antigen 1 (AMA1), upon host invasion. Themolecular cloning of subtilase has been tried for the full gene but it was successful due toGC-rich sequences and very long size. For functional analysis of subtilase, partialcatalytic domain of about 600 bp was cloned into Escherichia coli and a malarial vector,pfGN-FTC at the same time, Correspondence to : Suk-Yul Jung.G-17-03Cloning, overexpression, and purification of a cold-active Pseudomonasmandelii lipase from Escherichia coliJunsung Kim, Seunghee Hong, ChangWoo Lee, and Sei-Heon JangDepartment of Biomedical Science, Daegu University, Gyeongsan 712-714, KoreaCold-active lipases are widely used in pharmaceutical and textile industries. In this study,we cloned, overexpressed, and purified a cold-active lipase from Pseudomonas mandeliiisolated from natural mineral water in Gyeongsan, Korea. Pseudomonas mandeliipossesses desirable characteristics for industrial applications with the production of coldactiveenzymes and the ability of growth at 4 ℃, but not at 37 ℃. The cDNA for 1,710nucleotide lipase was cloned into pET28 vector by polymerase chain reaction with a C-terminal 6xHis tag. The P. mandelii lipase was ovexpressed in E. coli BL21(DE3) andsoluble proteins were isolated by sonication followed by Nickel-affinity columnchromatography. The molecular mass of the lipase was determined to be approximately61 kDa by SDS-PAGE. Lipase activity was measured using p-nitrophenyl esters assubstrates. We will discuss the use of cold-active lipase from Pseudomonas mandelii inindustrial applications.G-17-06Probing critical regions for the specific in vivo interaction between theHIV-1 nucleocapsid and psi(Ψ) RNA by alanine scanning mutagenesisJi Won Woo and Ji Chang YouNational Research Laboratory of Molecular Virology, Department of Pathology, School of Medicine,The Catholic University of Korea, Seoul 137-701, KoreaWe developed previously a cell-based in vivo assay that probes the specific interactionbetween nucleocapsid (NC) protein and Psi (Ψ) RNA, the human immunodeficiency virus(HIV) packaging signal. This assay system would facilitate investigation of the NC-Ψinteraction in vivo. In order to probe further critical regions for the specific in vivointeraction between the HIV-1 Nucleocapsid and Ψ RNA, we examined the effect of theNC mutants generated by alanine scanning site-directed mutagenesis. The resultsgenerated each different β-galactosidase activity for binding NC mutants with Ψ RNA.This effect is due to differential translation inhibition activities by NC alanine point mutantswith the Ψ sequence. This study suggests that the cell based assay developed for NC-Ψinteraction can be further extended and applied to probing key regions for NC-binding.This assay provides not only an easy and efficient means of studying the NC-Ψinteraction in detail in vivo but also may also facilitate the screening and identification ofantiviral chemicals and bioactive molecules against NC and the NC-Ψ interaction.238 Korean Society for Biochemistry and Molecular Biology