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        검색결과 17

        1.
        2022.10 구독 인증기관·개인회원 무료
        Based on the results of a review for various precipitation methods phosphorylation (phosphate precipitation) of metal chlorides considered as a proper treatment method for recovering of the fission products in a molten salt. In previous precipitation tests, the powder of lithium phosphate (Li3PO4) added into LiCl-KCl molten salt containing metal chlorides as a precipitation agent. The reaction of metal chlorides containing actinides and rare earths to recover with lithium phosphate in a molten salt known as solid-liquid reaction. The powder of lithium phosphate disperse in a molten salt by stirring thoroughly in order to enhance the precipitation reaction. As a result, metal phosphates as the reaction products precipitate on the bottom of the vessel and cutting at the lower part of the salt ingot considered as one of the recovery method of the precipitates. Recently, the vacuum distillation of upper part of the salt proposed as another recovering method. Cutting method of precipitate at the lower part of the salt ingot would be difficult to handle the increased size of the salt ingot produced from the practical scale equipment. In this presentation, a new method for collecting the precipitates of phosphorylation reaction into a small vessel is introduced with test results in a molten salt containing uranium and rare earths such as Nd, Ce, and La. As the first step of a series of test lithium phosphate ingot was prepared by melting the powder at a temperature 1,300°C, and the ingot put into LiCl-KCl molten salt at 500°C for more than three hours to examine the shape of ingot to be deformed or not. The phosphorylation experiments using lithium phosphate ingots carried out to collect the metal phosphate precipitates and the test result of this new method was feasible.
        2.
        2022.10 구독 인증기관·개인회원 무료
        Under the circumstance of energy transition policy of the previous government in which nuclear energy portion will be gradually reduced, some R&D study looking for alternatives other than Pyro- SFR recycling could be very valuable and timely suitable. New alternative study started to evaluate the possibility of it if there are some advantages in terms of waste burden in case that the spent fuel are appropriately treated and disposed of in a disposal site, instead of recycling of spent nuclear fuels (SNF). The alternative study separate the fission products (minor actinides and rare earths) from SNF in a molten salt medium. The molten salt coming from the alternative study is radioactive and heat generating because it contains the fission products chlorides. It is necessary to collect the fission products from the waste molten salt for minimization of the high-level waste volume and to generate a final waste form containing the fission products compatible to the disposal site. Based on the results of a review for various precipitation methods, phosphorylation (phosphate precipitation) of metal chlorides selected as a proper treatment method for recovering of the fission products in a molten salt. Phosphate precipitation has the potential for removing most of fission product elements from a molten salt arising from the treatment of spent nuclear fuel. The performance of phosphate precipitation method evaluated using a salt mixture with the actinide and rare earth chlorides. The molten salt containing uranium as surrogate of the actinides and three rare earths (Nd, Ce, La) chloride was used for testing a phosphate precipitation method at experimental condition (temperature 500°C, salt stirring 200~300 rpm, and 1~1.2 eq. of phosphorylation agent). A cyclic voltammetry (CV) method monitored in-situ phosphate precipitation progress for determining the precipitation rate and conversion ratio evaluated. The phosphorylation reaction increased greatly at a salt stirring 300 rpm.
        4.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Equine follicle stimulating hormone receptor (eFSHR) has a large extracellular domain and an intracellular domain containing approximately 10 phosphorylation sites within the G protein-coupled receptor. This study was conducted to analyze the function of phosphorylation sties at the eFSHR C-terminal region. We constructed a mutant of eFSHR, in which the C-terminal cytoplasmic tail was truncated at residue 641 (eFSHR-t641). This removed 10 potential phosphorylation sites from the C-terminal region of the intracellular loop. The eFSHR-wild type (eFSHR-wt) and eFSHR-t641 cDNAs were subcloned into the pCMV-ARMS1-PK2 expression vector. These plasmids were transfected into PathHunter CHO-K1 Parental cells expressing β-arrestin 2 enzyme acceptor fusion protein and analyzed for agonist-induced cAMP response. The cAMP response in cells expressing eFSHR-t641 was lower than the response in cells expressing eFSHR-wt. EC50 values of eFSHR-wt and eFSHR-t641 were 1079 ng/mL and 1834 ng/mL, respectively. eFSHR-t641 was approximately 0.58-fold compared with that of eFSHR-wt. The maximal response in eFSHR-wt and eFSHR-t641 was 24.7 nM and 16.7 nM, respectively. The Rmax value of phosphorylation sites in eFSHR-t641 was also decreased to approximately 68.4% of that in eFSHR-wt. The collective data implicate that the phosphorylation sites in the eFSHR C-terminal region have a pivotal role in signal transduction in PathHunter CHO-K1 cells, and indicate that β-arrestin is involved in coupling the activated receptors to the internalization system.
        4,000원
        5.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ganglioside GD1a is specifically formed by the addition of sialic acid to ganglioside GM1a by ST3 β- galactoside α -2,3-sialyltransferase 2 (ST3GAL2). Above all, GD1a are known to be related with the functional regulation of several growth factor receptors, including activation and dimerization of epidermal growth factor receptor (EGFR) in tumor cells. The activity of EGF and EGFR is known to be a very important factor for meiotic and cytoplasmic maturation during in vitro maturation (IVM) of mammalian oocytes. However, the role of gangliosides GD1a for EGFR-related signaling pathways in porcine oocyte is not yet clearly understood. Here, we investigated that the effect of ST3GAL2 as synthesizing enzyme GD1a for EGFR activation and phosphorylation during meiotic maturation. To investigate the expression of ST3GAL2 according to the EGF treatment (0, 10 and 50 ng/ml), we observed the patterns of ST3GAL2 genes expression by immunofluorescence staining in denuded oocyte (DO) and cumulus cell-oocyte-complex (COC) during IVM process (22 and 44 h), respectively. Expression levels of ST3GAL2 significantly decreased (p<0.01) in an EGF concentration (10 and 50 ng/ml) dependent manner. And fluorescence expression of ST3GAL2 increased (p<0.01) in the matured COCs for 44 h. Under high EGF concentration (50 ng/ml), ST3GAL2 protein levels was decreased (p<0.01), and their shown opposite expression pattern of phosphorylation-EGFR in COCs of 44 h. Phosphorylation of EGFR significantly increased (p<0.01) in matured COCs treated with GD1a for 44 h. In addition, ST3GAL2 protein levels significantly decreased (p<0.01) in GD1a (10 μM) treated COCs without reference to EGF pre-treatment. These results suggest that treatment of exogenous ganglioside GD1a may play an important role such as EGF in EGFR-related activation and phosphorylation in porcine oocyte maturation of in vitro.
        4,000원
        6.
        2011.10 구독 인증기관·개인회원 무료
        Phosphorylation of proteins is a post-translational modification process which plays a significant role in a wide range of cellular processes. Addition or removal of phosphate groups result in conformational changes in proteins leading either to their activation or inactivation. Tyrosine phosphorylation of protein is associated with sperm function in several mammalian species. The control of this process may via the changes in cyclic adenosine monophosphate (cAMP); the changes in cAMP levels that occur in the spermatozoa regulate protein kinase A (PKA) activity which, in turn, leads to the tyrosine phosphorylation of protein substrates by either the activation of sperm tyrosine kinases and/or the inhibition of phosphoprotein phosphatases. Cyclic nucleotides, in particular, cAMP, are important regulators of various maturation events in sperm including capacitation and motility. Interestingly, some environmental chemicals (ECs) may exert broader endocrine disrupting effects through possible modulation of cAMP/PKA second messenger systems. Otherwise, because the mature spermatozoa are transcriptionally inactive, therefore the study of sperm proteins phosphorylation may permit more information about the agents and conditions affects on sperm function. In the present study, to examine the effect of ECs on human sperm function, human spermatozoa were incubated with a group of ECs represent a widespread chemicals in the environment bisphenol A (BPA, 100 μM), nonylphenol (NP, 10 μg/ml), 2,3,7,8-Tetrachlorodibenzo- pdioxin (TCDD, 2.5 μg/ml), genistein (Gen, 100 μM), and the following pesticides, dibromochloropropane (DBCP, 10 μg/ml), atrazine (Atraz, 500 μM), and diazinone (Diaz, 500 μM) for 6 hr at 37℃ in 5% CO2. Then, western blot analysis was carried out using extracted sperm proteins. Antiphosphorylation antibody (pY20) was used to determine sperm tyrosine phosphorylation after EDs treatment. The pY20 antibody labeled three common bands of approximately 90, 110, and 150 KDa. There were no significant differences between negative and positive control groups in regard to the tyrosine phosphorylated proteins except at the band with molecular weight 110 KDa. However, except Diaz treatment group, the other treatment groups showed decreasing (TCDD, Gen, NP, BPA, and DBCP) or increasing (Atraz) in the tyrosine phosphorylated proteins at least in one band from the three common bands studied. Therefore, it sug-gests that ECs effectively alters human sperm function and this effect may detect via their effect on tyrosine phosphorylation pattern.
        11.
        2007.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        ( - ) -epigall ocatechin - 3 -ga ll ate(EGCG) 는 녹차에서 추출되는 주된 성분으로 항산화. 세포 증식 억제 및 세 포 자멸사를 유도힌다 고 알려져 있다‘ 현 재 끼지의 여러 연구에 의하띤 EGCG는 세 포 성장을 억제하고 나아가서는 apoptoS1S까지도 유발한다. 한편 일부 연구는 EGCG가 오히려 apo ptosi s를 억 제 하고, 세 포 증식을 촉진한다고 보고하고 있다. 저자들은 EGCG가 이러한 상반된 효과틀을 보이게 되 는 기전과 그에 관련된 물질들을 파악하고지 하였다, EGCG를 세포에 처리시 초기에는 세포 생존에 관여힌다고 알려진 인 산화된 Akt 단백이 증가함이 관찰되었다 그 외에도 인산화된 Erk 단백 등의 증가로 EGCG가 세포 생존을 지속시키 는 역할을 하고 있음을 알 수 있었다‘ 이러한 현상은 COS7 과 A549 세 포 에서 관찰되었으며 Hela 세포에서는 관찰되지 않아 세 포외부에서 EGCG가 결합하게 되 는 물질 혹은 세 포내 물질 등의 차이에 의해 세 포 미다 EGCG에 대한 반응이 다른 것으로 추측된다 24시간 이상 처리된 경우 ECCG가 세 포 생존에 관린된 인자들을 감소시키는 것으로 보아 EGCG에 처음에는 세 포 생존을 유도하지만 장시간 처리 시 세 포 증식 및 생존을 억제하는 물질 임 을 확인하였다.
        4,000원
        12.
        2007.10 KCI 등재 구독 인증기관·개인회원 무료
        In t his study, we tried to identify the key elements that respond to EGCG t reatment and its role in cell survival 0 1' apop tosis by EGCG. focusing on Akt pathway and Raf-MEK-ERK pathways. Cells were serum starved for 16 h and then treated with (-) -epiga llocatechin-3-gallate. To cletermine which pathway is related to effects of EGCG on cell s, the levels of phosphorylated Akt(pAkt) and Erk (pErk) were a nalyzed by immunoblotting. A549 cell s showed the increase of pAkt in response to EGCG‘ whereas Hela cells exhi bited no difference in the levels of pAkt by EGCG treatment Phos phorylation of Akt over initial basal levels became evident a fter 1 h of EGCG treatment and peaked at 3 h pErk was also increased by EGCG in Hela cells as well as in A549 cells To determine th e effect of EGCG on growth of cells‘ A549 cells were treated wi th vari 。u s concentrations of EGCG (from 10 μ M to 300 μ M) for 3 h. Cell growth was examined by MTI assay. The resulting growth curves of A549 cell s showed that EGCG promotecl cell prolifera tion in a close-dependent manner at early phase. When cells were t rea ted with EGCG for 24 h. pAkt and pErk expressions were significantly i띠1ibited , even at 10 μ M B-raf ex pression was also clecreased in a close-dependent manner. In teresti ngly. the presence of serum weakened t his inhibitory effect of EGCG on the ex pression of survival facto rs. Our study inrucates that EGCG stimulates cell survival of A549 cells through thc PI3K/AKT pathway. though it fina lly be haves like a suppressive agent on cell su rvival
        15.
        2020.08 KCI 등재 서비스 종료(열람 제한)
        이상의 연구 결과로 먹넌출 열매 추출물은 GSK3β 의존성 Cyclin D1 단백질의 분해를 통해 대장암세포의 생육 억제와 관련이 있는 것으로 확인된다. 본 결과는 대장암의 항암제 개발을 위한 소재로 먹넌출 열매의 활용이 가능할 것으로 판단된다.
        16.
        2018.06 KCI 등재 서비스 종료(열람 제한)
        The large extracellular domain of glycoprotein hormone receptors is a unique feature within the G protein-coupled receptors (GPCRs) family. After interaction with the hormone, the receptor becomes coupled to Gs, which, in turn stimulates adenylyl cyclase and the production of cAMP. Potential phosphorylation sites exist in the C-terminal region of GPCRs. The experiments described herein represent attempts to determine the functions of the eel follicle-stimulating hormone receptor (eelFSHR). We constructed a mutant of eelFSHR, in which the C-terminal cytoplasmic tail was truncated at residue 614 (eelFSHR-t614). The eelFSHR-t614 lacked all potential phosphorylation sites present in the C-terminal region of eelFSHR. In order to obtain the eelFSHR ligand, we produced recombinant follicle-stimulating hormone (rec-eelFSHβ/α) in the CHO-suspension cells. The expression level was 2-3 times higher than that of the transient expression of eelFSH in attached CHO-K1 cells. The molecular weight of the rec-eelFSHβ/α protein was identified to be approximately 34 kDa. The cells expressing eelFSHR-t614 showed an increase in agonist-induced cAMP responsiveness. The maximal cAMP responses of cells expressing eelFSHR-t614 were lower than those of cells expressing eelFSHR-wild type (eelFSHR-WT). The EC50 following C-terminal deletion in CHO-K1 cells was approximately 60.4% of that of eelFSHR-WT. The maximal response in eelFSHR-t614 cells was also drastically lower than that of eelFSHR-WT. We also found similar results in PathHunter Parental cells expressing β-arrestin. Thus, these data provide evidence that the truncation of the C-terminal cytoplasmic tail phosphorylation sites in the eelFSHR greatly decreased cAMP responsiveness and maximal response in both CHO-K1 cells and Path-Hunter Parental cells expressing β-arrestin.
        17.
        1999.06 KCI 등재 서비스 종료(열람 제한)
        생쥐 초기 배아의 형태형성에 영향을 주는 세포질내 인자의 기원과 작용기작을 연구하기 위해 단백질 합성과 단백질 활성화 효소 (protein kinase)의 억제제를 처리한 배아의 세포질로 재조합된 배아에서 발생과 RNA합성, 단백질 인산화를 조사하였다. 단백질 합성 억제제인 cycloheximide (CHX)가 함유된 배양액에서 24시간 배양한 1-세포 배아의 제핵된 세포질을 두 개의 전핵을 모두 가진 절반의 1-세포 배아와 재조합한 P+P-CHX군의