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        검색결과 25

        3.
        2021.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We study galaxies undergoing ram pressure stripping in the Virgo cluster to examine whether we can identify any discernible trend in their star formation activity. We fi rst use 48 galaxies undergoing different stages of stripping based on Hi morphology, Hi de ficiency, and relative extent to the stellar disk, from the VIVA survey. We then employ a new scheme for galaxy classi fication which combines Hi mass fractions and locations in projected phase space, resulting in a new sample of 365 galaxies. We utilize a variety of star formation tracers, which include g - r, WISE [3.4]-[12] colors, and starburstiness that are de fined by stellar mass and star formation rates to compare the star formation activity of galaxies at different stripping stages. We find no clear evidence for enhancement in the integrated star formation activity of galaxies undergoing early to active stripping. We are instead able to capture the overall quenching of star formation activity with increasing degree of ram pressure stripping, in agreement with previous studies. Our results suggest that if there is any ram pressure stripping induced enhancement, it is at best locally modest, and galaxies undergoing enhancement make up a small fraction of the total sample. Our results also indicate that it is possible to trace galaxies at different stages of stripping with the combination of Hi gas content and location in projected phase space, which can be extended to other galaxy clusters that lack high-resolution Hi imaging.
        5,400원
        4.
        2016.04 구독 인증기관·개인회원 무료
        Human body and head lice are obligatory human ectoparasites. Although both body and head lice belong to a single species, Pediculus humanus, only body lice are known to be a vector of several bacterial diseases. The higher vector competence of body lice is assumed to be due to their weaker immune response than that of head lice. To test this hypothesis, immune reactions were compared between body and head lice following infections by two model bacteria, Staphylococcus aureus and Escherichia coli, and a human pathogen, Bartonella quintana. Following dermal or oral challenge, the number of these bacteria increased both in hemocoel and alimentary tract of body lice but not in head lice and the viability of the B. quintana was significantly higher in body louse feces, the major route of infection to human. In addition, body lice showed the lower basal/induced transcription level of major immune genes, cytotoxic reactive oxygen species and phagocytosis activity compared with head lice. These findings suggest that a reduced immune response may be responsible, in part, for the increased proliferation and excretion of viable bacteria which are associated with the high level of human infectivity seen in body versus head lice.
        5.
        2007.04 KCI 등재 구독 인증기관·개인회원 무료
        Epithelial-mesenchymal transition(EMT) plays a pivotal role in the convers ion of earl y s tage tumors into invasive malignancies‘ and has been shown to be regulated hy the transcri ptional factor. Snail. Recent ly‘ actlvatlon of the phosphatidylinositol 3' kinase (PI3K)/따<:T axis is emerging as a centra l feature of EMT‘ However. it is unclear whether the phosphorylation of AKT regulate the expl'ession of s nail in ora l cancer cell underwent EMT. T。 investigate a role of p-AKT in EMT, we assessed the effects of inhibi ting p-AK1' activity in oral squamous can cer cells(KOSCC-25B) using PIAs, structurally modified phosphatidyli nositol ether lipid analogues(P1As) . PIAs de creased phosphorylation of c-Jun N-terrninal Kinase(JNK) and increased phosphorylation of glycogen synthase kinase 3beta(GSK-3beta). Inhibition of p-AKT ir빼ce d down regulation of Snail and Twist. but Sip1 regulated independent of p-AKT inhibition. Also inhibi tion of p-AKT dec reased cell migration and invas ion. Therefore our results implicate that p-AKT may contribute to the translocalization of sna il in the EMT associated with canceJ cell rnigration and invasion
        6.
        2007.04 KCI 등재 구독 인증기관·개인회원 무료
        [n order to obtain the trlle expected DNA prod uct from PCR and RT-PCR using genornic DNA or cDNA reversely transcribed from mRNA. the PCR should be done in an appropriated condition. Sometimes the PCR was repeatedly fail ed. and cventllally the PCR product was turned out to be nonspecific and rudimentary . And more‘ t he PCR prodllctwas not reproducible even though careflll repeat of experiments. As the PCR was based on the exact primel hybridization. the condition of primer hybridization should be properly controlled by a nnealing temperatllre. But the selection of primer seqllences for targeting a specific gene is mostly important. A new method of primer eval uation is now available llsing DNA base pair polarity program. This study presents an example of PCR targeting to human Bax gene using genomic DNA. The DNA base pair polarity theory can di vide the genetic cord into propel DNA segments and calclllaLe their DNA base pair hybridization energy. Thus. mathematically the degree 0(' exact primer hybridization can be expected for the t r1l8 targeting of PCR. However, the DNA base pair polal'ityanalysis demonstrates that the more frequent number of DNA segment incl'eased the specificity of PCR. but decreased its sensitivity . While the greater polarity of DNA segment composed of increased nllmber of polarized DNA base pairs showed increased sensitivi ty 0 1' PCR. bllt relati vely decreased specificity of PCR. With the mllltiple analysis of PCR. especially for PCR cloning from the gDNA and cDNA, we found that the primers themselves showed secondary strllcture of partial hybridization between sameprimers or each pair primers. The DNA base pail‘ polarity signal can directly demonstrated symmetric sequences 0 1' each primer. and also can distinguish the dimmer formation from each pair primers. At least the symmetric seqllence of fOlll‘ base pairs dramatically showed the dimrner formation. On the other hand. in addi tion Lo the statlls of DNA base pair polarity the three-dimensional strllctllre of DNA dOllble helix targeted by the primer seqllences may affect the sensitivity and specificity of PCR detection. The present study introduced a new method of primer evalllation and selection in order to obtain abundant and exacL! y-trlle DNA product for genomic ffilltation analysis and gene expression profï le
        7.
        2007.04 KCI 등재 구독 인증기관·개인회원 무료
        Although a number of molecules have been implicated in the metastasis of oral squamous cell carcinoma (OSCC) , the precise molecular mechanisms that deterrnine the direction of rnigration and invasiveness of OSCC cells into the lymph nodes remain unclear, Chemokines are a superfarnily of small structurally related heparin- binding proteins‘ which have been identified as attractants that control the rnigration of leukocytes‘ especia lly during imrnune and inflammatory reactlOns Moreover, recent studies have demonstrated that several types 。f cancer express chemokine receptor‘s and use chemokines to metastasize to the target organ, However, there h ave been few reports on biological behaviors by downregulation 0 1' CXCR-4 in ora l cancel‘ cells We tried to screen several OSCC cell lines in order to obtain a suitable cell line model which had the cha ract eris tic of the constitutive ly expressed state of CXCR• 4 Of the several OSCC cell lines, only KOSCC-25B showed the high expression of CXCR-4 in both RT-PCR and Western blot analysis, siRNA-CXCR-4 infected subclones of KOSCC-25B(Si, 3‘ Si 1이 showed downregulation of CXCR-4 expression as expected‘ At serum-free co ndi tion‘ Si.3 s ubclone s ignif icantly decreased cell proliferations at 24 h and 48h and Si, lO subclone significant ly dec reased cell proliferations at 24 h Si ,3 clone dec reased to 67 ,4% and Si,lO clone to 65 ,5% in comparison to vector infected cells These data suggest that the downregulation of CXCR-4 expression could induce anti-rnigratory and ant i- rni g ratory effect
        8.
        2005.10 KCI 등재 구독 인증기관·개인회원 무료
        Gene reg비 at i o n during the human craniofacial development is not well understood In effort to understand n ewly identifï ed genes that may play role(s) in the human craniofacial development, non-redundan t genes were isolated from the s ubtracted cDNA libra ry of human embryonal craniofacial tissues and examined their possible structu ral rolc in parallcl with thosc gcncs from isolatecl human c h o nclroc)πes cDNA library. Fifty genes were init ia ll y chosen from 398 clones iso latecl were used for selective dominant expression in both chondrocytes and the craniofacial sections of 10 weeks old human embryo by in situ hybridization method. Based upon the high levels 。f expression, we have identifi ecl seven unknown genes; ch89, ch96. ch129. ch 153. ch 276 ch285. and ch334 . In 。rder to unde rs tancl the possi ble role of these genes‘ the structural simulation of the expressed proteins were constructecl by Sybyl 6.6 program. Ch 276 gene was same with a clone, c14 0 1' f173. registered in GenBank(NM_022489) a nd is composed 0 1' 323 amino acids having a reverse s ignaling domain from the extra- cellular matrix(C-terminal) to cell membrane(N-terminal) and 12 turns of helical structure. Gene protein also r etains a famil iar fïbronectin binding domain(RGD). three s ites 0 1' Ca ion binding motifs. cAMP- and cGMP-dep endent protein kinase phos phorylation site, two regions of protein kinase C phosphorylation s ites. glyco- saminoglycan attachment s ite ancl N-glycosylation site. transmembrane and Al kaline Phosphatase active s ite domains This newly iclentifï ed human protein from human choncl rocytes cDNA library appearecl to be related to a known calcification s ignaling protein. was named as Ca lsin(Ch276) . Ch153 appeared to be related a family of anti-microbial peptide acting as an inflammation mediator and Ch334 clone as a zinc finger protein whose expression in creases in human adult ti ssue‘ These results suggest that these novel genes ident i!ï ed from human chondrocytes rnay provide a new path 0 1' embryonic cartilage development and human craniofacial development.
        9.
        2005.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The p16 gene encodes an inhibitor of the cyclin-dependent kinase, which inactivates cyclin-dependent kinase and contro1s the cell cycle progression, The 10ss of p16 expression or overexpression has been reported in many kinds of tumors, Both p16 and PCNA regu1ates cell cycle progression at the Gl/8 checkpoint, Although many researches about the p16 expression in ora1 cancer have been carried out, there are few studies about the corre1ation between p16 ex pression and pro1iferation of ora1 cancer cells The object of this study was to eva1uate the avai1ability of p16 as ear1y diagnostic factor and prognostic factor through corre1atión ana1ysis of p16 expression in ora1 squamous cell carcinoma and its re1ation to PCNA index and clinicopatho1ogic factors 80 we investigated p16 immunohistochemica1 expression of 83 ora1 squmaous cell carcinomas, and obtained the resu1ts as followed, 18 out of the 83 cases(21, 69%) showed p16 positive and 65 samp1es(78,31%) showed p16 negative, Whi1e the mean va1ue of PCNA indices of p16 positive cases was 65,94 ::t 18,32, that of PCNA indices at p16 negati ve ones 54,79 ::t 18, 39, This difference between them showed statistica1 sígnificance, (P=O, 030) p16 positive group was 12/60(20, 0%) of well differentiated tumors and p16 negative group was 6/23(16, 1%) of moderate1y or poor1y differentiated tumors, This difference did not show statistica1 significance. (P=O. 372) From the resu1ts above, it was suggested p16 expression is re1ated to PCNA index in ora1 squamous cell carcinomas.
        4,200원
        10.
        2004.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        ReαlITent aphthous stomatitis (RAS) appears to be one of the most common oral diseases. However, the defmitive etiology of RAS is not well established, though many etiologic faαors have been suggested and examined. The present study was petformed to investigate the association between HIA and Korean recurrent aphthous stomatitis pa디ents. πle proportions of class 1 and class II HIA types expressed in 49 Korean subjects affected by recurrent aphthous stomatitis (RAS) and in 50 healthy controls were deteffi1Í11ed by microlymphocytotoxicity test. 까le sig띠ficance of the data was analyzed by chi-square test and Fisher' s exact test. πle proportions of HIA-Cw1 and -DR9 antigens were significantly higher in RAS pa디ents (p(0.05), whereas those of HIA-DR4 and -DQ2 antigens were significantly lower (p(0.05). 까le odds ratio (OR) were 2.8 for HIA-Cw1 and 2.7 for -DR9. πle etiologic fractions (EF) were 0.262 and 0.193, respectively. The results s맹gest that, in Koreans, there Í$ a sig띠ficant relation between HIA antigens and RAS. Genetic faαors , reflected in the HIA type, may play an in1portant role in the development of RAS.
        4,000원
        12.
        1999.12 KCI 등재 구독 인증기관·개인회원 무료
        13.
        2018.12 KCI 등재 서비스 종료(열람 제한)
        Roasting has revealed coffee’s potentials as a good source of bioactive compounds. This study was done to investigate the quantitative presence and activity of bioactive compounds including caffeine, chlorogenic acid (CGA), amino acids, and antioxidant capacity on Coffea arabica L. (Guatemala finca San Sebastian) and C. robusta L. (India Azad Hind). Analysis was performed on Green Bean (GB) Medium-Light (ML), Medium (ME) and Medium-Dark (MD) samples of both varieties. From the results, caffeine content was highest in ME samples of both varieties. GB samples of both varieties had high CGA content which decreased after increasing roasting time and temperature. Most amino acids in GB samples was highest, however, glutamic acid, valine, tyrosine, isoleucine, leucine and phenylalanine had highest quantitative increase in ME samples for both varieties. IC50 of DPPH and ABTS radical scavenging activity was highest in ML samples of both varieties. IC50 of reducing power and total phenolic content was highest in GB sample of both varieties but decreased after increasing roasting conditions. Generally Robusta had the highest quantity of bioactive compounds and antioxidant activity. From this study, the optimal roasting condition for coffee is ME above which there is a significant reduction of bioactive compounds and antioxidant activity.
        14.
        2014.07 서비스 종료(열람 제한)
        Foxtail millet (Setaria italica L.) is the second most widely cultivated species of millet, especially in East Asia and is a tractable experimental model crop for studying functional genomics of millets. However, insufficient researches had been conducted about the foxtail millet germplasm and is significantly impeding its genetic improvement. We attempted to develop EST-derived-SSR (eSSR) markers and utilize them in genetic comparison of germplasm and transferability. A total of 66,027 foxtail millet EST sequences and 42,754 genomic sequence were deduced transcriptom. Approximately 42,000 single tone contigs were generated using DNAstar 5.0 software for redundancy minimization. Nearly 33% of the 14,012 unigenes contained SSRs, but primers were designed for a total of 314 microsatellites concentrating with more than 24 bp of repeats. A total of 314 primers were successfully designed with more than 24 bp of repeats. From these microsatellites, 56 primer pairs were showed polymorphism with over than 15 bp differences among 96 accessions collected from different countries. Polymorphic information content (PIC) value ranged from 0.020 to 0.700 with an average of 0.381 indicating moderate level of informativeness within these EST-SSRs markers. The EST-SSR markers developed in this study will serve as a useful source for genetic studies, such as genetic variability, transferability, association mapping, and molecular breeding
        15.
        2014.07 서비스 종료(열람 제한)
        Rice blast (Magnaporthe oryza B.) is one of the most widespread and devastating diseases of rice. Screening of valuable genetic resources harboring resistance genes is one of the most efficient approaches against blast disease. Because the bioassay to rice blast in the field shows high variations, this study has performed to provide DNA profiles in the accessions of diverse countries using major blast resistant genes linked markers, identified and mapped in different genotypes of rice. Because durable resistance to blast is controlled by a combination of major resistance genes, we surveyed the distribution of blast resistant genes in the 1,500 accessions using major 12 blast resistance genes linked markers. These resistant genes found that the frequency distribution of Pi-39 (66.9%), Pik-m (41.9%), Pit (40.5%), Pii (21%), Pib (19.3%), Pi-d(t)2 (12.7%), but Pita, Pita/Pita-2, Pik, Piz-t, Pi5 genes were identified in less than 10% frequency. Most of accessions contain from 1 to 4 different resistant genes. Pi39 and Pik-m genes amplified in the 69.1% and 51.7% among 356 Korean accessions, Pi39 (79.6%) and Pib (55.8%) in 113 China, Pit (80.6%) and Pib (32%) in 103 Philippines, respectively. In this study, we evaluated the blast resistance degree and the information about the distribution of rice blast resistant genes in rice germplasm. This study will help to develop effective strategies for managing rice blast disease in rice germplasm.
        16.
        2012.07 서비스 종료(열람 제한)
        The genus Rubus belongs to the Rosaceae family and is comprised of 600-800 species distributed worldwide. Understanding the genetic relationships and genetic structure in Rubus species is important for enabling efficient management, conservation, characterization and utilization of the species. However, as a minor crop, genetic research foundation was limited to explore genetic diversity and relationships in Rubus species. The present study shows the results of application SSR markers that were developed from SSR-enriched libraries of the one Rubus species (Rubus coreanus Mique.) in our previous study. We used 34 polymorphic microsatellite markers to analysis of genetic diversity within the Rubus species, including redraspberry, blackraspberry, blackberry and mountainberry. All the 34 SSR primers pairs produced 483 polymorphic and reproducible amplification fragments. The largest number of alleles per primer pair was confirmed at GB-RC-167, GB-RC-100, GB-RC-076 and GB-RC-245, which contained 26, 25, 23 and 21, respectively. An average value of polymorphic information contents (PIC) were 0.74 with a range of 0.36 to 0.92. Population structure and phylogenetic analyses showed that all Rubus species formed three largely distinct clusters, which were confirmed by principal coordinate analysis (PCoA). We obtained the results that the developed SSR markers showed a substantial degree of genetic diversity in the various Rubus species distributed in Korea.
        17.
        2010.06 KCI 등재 서비스 종료(열람 제한)
        19.
        2009.03 KCI 등재 서비스 종료(열람 제한)
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