열처리에 따른 Poly(Ethylene Terephthalate-co-Sebacate)의 가수분해에 관한 연구

백애란,최은경 효성여자대학교 가정대학 학도호국단 1984 家政大論集 Vol.3 No.-

In order to modificate polyester fiber, the polyethylene terephthalate(PET) was copolymerized with sebacic acid(SA). In this experiment the substitution rate of comonomer(SA) was controlled from 5 mil% to 30mil%, and all samples were used in film. When the hot-pressed films were hydrolyzed at 80℃ by using 10% NaOH, the weight loss increased with increasing SA mol% of copolyester. On the other hand, when the films were heat-treated the weight loss of PET and the copolyester containing 5 or 10 mol% of SA were increased. But the weight loss of the copolyester containing 20 or 30 mol% of SA were lowered.

개불과 넙치의 혼합 사육시 성장과 사육환경의 변화

김용구,박일웅,안윤근,배애란,최상덕 國立麗水大學校 環境問題硏究所 2004 環境硏究論文集 Vol.6 No.-

This present study was conducted to determine the effects of sea water quality and sediment quality on growth and body composition in poly culture system, Paralichthys olivaceus and Urechis unicinctus. The seawater temperature of the experimental groups was ranges of 17.1~23.8℃, the lowest in 0 day and the highest in 70 day. The concentration of COD was 1.2~1.6㎎/ℓ, DIN 6.19~28.89㎎/ℓ in the D group. Mean IL concentration was 5.42~5.07% and it was maximum in 0 day and relatively minimum 70day. The concentration of AVS was 0.36~0.22㎎/g-dry, COD 4.36~4.08㎎/g-dry in the D group. Growth and feed intake of fish were affected by diets and feeding frequencies(P<0.05). There were differences at all experimental groups especially C group and control group but A, B group and C, D group were not difference. The lowest increased body weight was observed 4.7g in the D experimental group and the highest experimental group was observed 8.6g in the C group.

Attenuation of Colchicine Toxicity in Drug-resistant Cancer Cells by Co-treatment with Anti-malarial Drugs

CHOI, AE-RAN,KIM, JU-HWA,CHEON, JI HYUN,KIM, HYUNG SIK,YOON, SUNGPIL Potamitis Press 2016 Anticancer research Vol.36 No.11

<P>Background/Aim: Colchicine (COL) is a wellknown and potent microtubule targeting anticancer agent. The purpose of our study was to identify conditions that increase sensitization of COL-resistant cancer cells that overexpress P-glycoprotein (P-gp). Materials and Methods: The anti-malarial drugs chloroquine (CHL), mefloquine (MEF) and primaquine (PRI) have been shown to increase sensitization in drug-resistant KBV20C cells via P-gp inhibition. Therefore, we tested whether co-treatment of COL with PRI, CHL or MEF increases sensitivity in COL-resistant KBV20C cells over that of cells treated with COL alone and whether these effects are attributable to P-gp activity. Results: Interestingly, we found that both CHL and PRI, but not MEF, reduced cytotoxicity in KBV20C cells receiving high concentrations of COL, suggesting that the effects of CHL and PRI have specific mechanisms among the anti-malarial drugs. The effects of CHL and PRI were specific to COL-resistant cells, since we did not detect a reduction in cytotoxicity in drug-sensitive parent KB cells. These data suggest that CHL and PRI inhibit the signaling pathways of COL-treated-resistant cells without P-gp inhibition. Furthermore, we studied the molecular mechanisms underlying the effects of COL-CHL co-treatment in KBV20C cells. FACS analysis, annexin V staining and western blot analysis revealed that G(2) arrest and apoptosis were lower in cells co-treated with COL and CHL than in cells treated with COL alone. We also found that pH2AX, pHistone H3 and pRb expression was highly reduced in COL-CHL co-treated cells but not in COL-VIB co-treated cells. In addition, expression of the p21 protein, which correlates with drug-resistant phenotypes, increased in cells receiving COL-CHL co-treatment over that of COL-treated cells. Conclusion: These results suggest that reduced G(2) arrest and apoptosis resulting from COL-CHL co-treatment was attributable to DNA damage and reduced cell cycle progression. These findings provide important information regarding the prevention of COL toxicity in COL-resistant cells and indicate that CHL, PRI and MEF may contribute to sensitization in COL-resistant cells.</P>

Identification and Cloning of the ClpB Gene in Psychromonas arctica by Inverse PCR and Cassette PCR Technology

Choi, Ae-Ran,Na, Joo-Mi,Sung, Min-Sun,Im, Ha-Na,Lee, Kyung-Hee Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.4

The family of ClpB protein is a molecular chaperone which protects cellular proteins from being aggregated upon exposure to severe environmental stresses in association with DnaK/DanJ/GrpE in the ATP-dependent manner. In a psychrophilic bacterium which survives at a subzero temperature, any functional role of cold-active ClpB protein can be rather crucial. In order to identify a ClpB encoding gene from a cold-adapted bacterium whose genome sequence has not been fully discovered, we have employed a series of PCR technologies, including a gradient PCR with homologous primers, an inverse PCR and a cassette PCR. The full sequence of PaclpB gene was successfully identified and compared with those of other psychrophilic species. We have further cloned the gene in E.coli expression systems and were able to induce PaClpB protein expression by IPTG, which help us understand a molecular mechanism for survival against extremely cold environments.

Co-treatment of LY294002 or MK-2206 with AZD5363 Attenuates AZD5363-induced Increase in the Level of Phosphorylated AKT

CHOI, AE-RAN,KIM, JU-HWA,WOO, YEON HWA,CHEON, JI HYUN,KIM, HYUNG SIK,YOON, SUNGPIL Potamitis Press 2016 Anticancer research Vol.36 No.11

<P>Clinical trials are in progress on AZD5363, an inhibitor of protein kinase B (AKT), to assess its effects on the phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway. Cells treated with AKT inhibitors have been reported to activate alternative pathways in order to escape growth inhibition. AZD5363-sensitized Hs578T breast cancer cells displayed reduced levels of phosphorylated glycogen synthase kinase 3 beta (pGSK3 beta). Interestingly, in AZD5363-treated cells, the level of phosphorylated (activated) AKT (pAKT) increased. Since pAKT positively correlates with cancer growth and survival, we aimed to identify conditions that could reduce AZD5363-induction of pAKT. We examined whether AZD5363 induction of pAKT could be reduced by co-treatment with inhibitors of the PI3K/AKT/mTOR pathway (LY294002, MK-2206, wortmannin, perifosine, rapamycin, everolimus, and temsirolimus). We observed that co-treatment of LY294002 or MK-2206 with AZD5363 reduced the level of pAKT. Since MK-2206 is clinically used, we propose that co-treatment using MK-2206 with AZD5363 would prove beneficial in blocking the AZD5363-induced pAKT signaling pathway. Our findings contribute to the development of AZD5363-based sensitization therapies for patients with cancer.</P>

Dimethyl sulfoxide reduction by a hyperhermophilic archaeon Thermococcus onnurineus NA1 via a cysteine-cystine redox shuttle

Ae Ran Choi,Min-Sik Kim,Sung Gyun Kang,Hyun Sook Lee 한국미생물학회 2016 The journal of microbiology Vol.54 No.1

A variety of microbes grow by respiration with dimethyl sulfoxide (DMSO) as an electron acceptor, and several distinct DMSO respiratory systems, consisting of electron carriers and a terminal DMSO reductase, have been characterized. The heterotrophic growth of a hyperthermophilic archaeon Thermococcus onnurineus NA1 was enhanced by the addition of DMSO, but the archaeon was not capable of reducing DMSO to DMS directly using a DMSO reductase. Instead, the archaeon reduced DMSO via a cysteine-cystine redox shuttle through a mechanism whereby cystine is microbially reduced to cysteine, which is then reoxidized by DMSO reduction. A thioredoxin reductase-protein disulfide oxidoreductase redox couple was identified to have intracellular cystine-reducing activity, permitting recycle of cysteine. This study presents the first example of DMSO reduction via an electron shuttle. Several Thermococcales species also exhibited enhanced growth coupled with DMSO reduction, probably by disposing of excess reducing power rather than conserving energy.

Argument Structure in the Science Writing Heuristic (SWH) Approach

( Ae Ran Choi ) 한국과학교육학회 2010 한국과학교육학회지 Vol.30 No.3

Sensitization of Cancer Cells through Reduction of Total Akt and Downregulation of Salinomycin-Induced pAkt, pGSk3 <i>β</i> , pTSC2, and p4EBP1 by Cotreatment with MK-2206

Choi, Ae-Ran,Kim, Ju-Hwa,Yoon, Sungpil Hindawi Publishing Corporation 2014 BioMed research international Vol.2014 No.-

<P>MK-2206 is an inhibitor of Akt activation. It has been investigated as an anticancer drug in clinical trials assessing the potential of pAkt targeting therapy. The purpose of this study was to identify conditions that increase the sensitivity of cancer cells to MK-2206. We found that the treatment of cancer cells with a high concentration of salinomycin (Sal) reduced total Akt protein levels but increased activated Akt levels. When cancer cells were cotreated with MK-2206 and Sal, both pAkt and total Akt levels were reduced. Using microscopic observation, an assessment of cleaved PARP, FACS analysis of pre-G1 region, and Hoechst staining, we found that Sal increased apoptosis of MK-2206-treated cancer cells. These results suggest that cotreatment with MK-2206 and Sal sensitizes cancer cells via reduction of both pAkt and total Akt. Furthermore, cotreatment of cancer cells with Sal and MK-2206 reduced pp70S6K, pmTOR, and pPDK1 levels. In addition, Sal-induced activation of GSK3<I>β</I>, TSC2, and 4EBP1 was abolished by MK-2206 cotreatment. These results suggest that cotreatment using MK-2206 and Sal could be used as a therapeutic method to sensitize cancer cells through targeting of the PI3K/Akt/mTOR pathway. Our findings may contribute to the development of MK-2206-based sensitization therapies for cancer patients.</P>

Selenate specifically sensitizes drug-resistant cancer cells by increasing apoptosis via G2 phase cell cycle arrest without P-GP inhibition

Choi, Ae-Ran,Jee Jo, Min,Jung, Myung-Ji,Sik Kim, Hyung,Yoon, Sungpil Elsevier 2015 european journal of pharmacology Vol.764 No.-

<P><B>Abstract</B></P> <P>The purpose of this study was to identify conditions that will increase the sensitivity of drug-resistant cancer cells. Selenium derivatives have been shown to present anti-cancer properties in the clinic. Currently, selenate, selenite, selenomethionine (SeMet), methyl-selenocysteine (MSC), and methaneselenic acid (MSA) are the most common selenium derivatives used as drugs in humans. Herein, we tested whether these selenium derivatives can sensitize KBV20C cancer cells, which are highly resistant to anti-cancer drugs such as vincristine. All five drugs could sensitize KBV20C cells to the same extent as they sensitized the sensitive parent KB cells, suggesting that selenium-derived drugs can be used for drug-resistant cancer cells. We also observed that these drugs did not inhibit the P-glycoprotein (P-gp) pumping-out ability, suggesting that the sensitization by selenium-derived drugs does not depend on P-gp activity in resistant KBV20C cells. Interestingly, using a cell viability assay, microscopic observation, and Hoechst staining, we found that selenate highly sensitized drug-resistant KBV20C cells by activating the apoptotic pathway, when compared to sensitive KB cells.</P> <P>Furthermore, we investigated why selenate sensitizes resistant KBV20C cells. Selenate-induced toxicity was associated with an increase in G2-phase cell cycle arrest in KBV20C cells, suggesting that the selenate-induced increase in apoptosis resulted from cell cycle arrest in resistant KBV20C cells. Our findings may contribute to the development of selenate-based therapies for patients resistant to cancer drugs.</P>

洛東江 下流城 濫藻 Anabaena의 個體群 變動 및 毒性 硏究

Choi, Ae-Ran,Park, Jin-Hong,Lee, Jin-Ae 한국조류학회(藻類) 2002 ALGAE Vol.17 No.2

Population dynamics of Anabaena and the anatoxin-a concentration were monitored with physicochemical parameters at 3 sites in the lower Naktong River from May to September in 2000. Total 4 species of Anabaena (A. flosaquae, A. smithii, A. ucrainica and A. mucosa) were identified with morphological characterisitcs. Anabaena flos-aquae was most abundant among the populations. The standing crop of Anabaena ranged from 10 to 11,220 cells · $ml^{-1}$ and biomass of Anabaena more 1,000 cells · $ml^{-1}$ was obseved once at St. Mulgeum and St. Seonam, twice at St. Hagueon out of total 9 samplings. There were not significant correlations between the standing crop of Anabaena and other physicochemical parameters such as temperature, nitrate, total nitrogen, phosphate, total phophorus and N/P ratios. The frequency of trichomes with akinetes was low and ranged from 0 to 4% in the total Anabaena population and A. smithii showed highest frequency of 2.8% among all species. The population at St. Seonam showed highest frequency of 1.4% among all sampling sties. The population in September showed the highest frequency of 3.0% among all sampling period. The frequency of trichomes with heterocysts was low and ranged from 1 to 87% inthe total Anabaena population and A. smithii showed highest frequency of 55.1% among all species. The population at St. Mulgeum showed highest frequency of 17.6% among all sampling sites. The population in August showed the highest frequency of 21.4% among all sampling period. The frequency of trichomes with akinetes and/or heterocysts was not related to all the physicochemical parameters of temperature, nitrate, total nitrogen, phosphate, total phosphorus and N/P ratios. The anatoxin-a concentations were determined in algal materials dominated by Microcystis and Anabaena from June though August by derivatization using 7-fluoro-4-nitro-2, 1,3-benzoxadiazole (NBD-F) and HPLC analysis with fluorimetric detection. All the concentrations were below the detection limit of 0.1 ㎍ · $l^{-1}$ in the present study.