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        검색결과 37

        22.
        2015.07 서비스 종료(열람 제한)
        Soybean is a short-day plant, which means short day length promotes flowering. So far nine major loci, E1 to E8 and J, affecting the timing of flowering and maturity have been genetically identified in soybean. To understand the roles of soybean flowering genes in photoperiod-dependent flowering time control in soybean, we analyzed not only expression patterns of E1, E2, E3 and E4 genes as well as soybean FT homologs, including GmFT2a, GmFT5a and GmFT4, but also structural variation of E1, E2, E3, and E4 genes in various soybean accessions exhibiting a broad range of flowering time. The mRNA level of GmFT2a and GmFT5a was low in late flowering accessions, but high in late flowering accessions. In contrast, GmFT4 exhibited opposite expression pattern to those of GmFT2a and GmFT5a. Structural variation of E1, E2, E3 and E4 gene in these accessions revealed that early and moderate flowering accessions contained non-functional alleles of E1, E2, E3 and E4 genes in their genome. These results suggested that expression patterns of GmFT2a GmFT5a and GmFT4 would be important factor determining flowering time in soybean and allelic variation and genetic combination of upstream E1, E2, E3, and E4 genes would be more important in soybean flowering time control than their gene expression patterns.
        23.
        2015.07 서비스 종료(열람 제한)
        FT is one of the major floral activator in photoperiod-dependent flowering pathway. To understand the role of FT homologs in flowering time control of short-day plant soybean, we identified ten soybean FT genes and named GmFTs. Phylogenetic analysis revealed that ten GmFT genes were further categorized into three subclades. Gene expression analysis showed that the most GmFT genes are mainly expressed in leaves. The expression of GmFT2a, GmFT2b, GmFT5a, and GmFT6 was strongly induced under the floral inductive short-day condition, but GmFT4 exhibited opposite expression pattern compared to those of GmFT2a, GmFT2b, GmFT5a, and GmFT6. To understand roles of GmFT genes in flowering, we generated Arabidopsis transgenic plant overexpressing GmFT genes. Both 35S:GmFT2a and 35S:GmFT5a transgenic plants showed extremely early flowering. In contrast, overexpression of GmFT4 delayed flowering of transgenic plants compared to wild type Arabidopsis. The results indicated that GmFT2a and GmFT5a might function as floral activators, while GmFT4 has an opposite function in soybean flowering. Moreover, domain swapping approaches between GmFT2a and GmFT4 revealed that the substitution of the segment B region alone, which is located in 4th exon, was sufficient to change the function of GmFT2a to floral repressor and GmFT4 to floral activator. The results suggested that soybean FT homologs have been functionally diversified during evolution and might play different roles in photoperiod-dependent flowering of soybean.
        26.
        2013.12 KCI 등재 서비스 종료(열람 제한)
        Science in the 21st century does not consider participants’ welfare, safety and human rights in clinical studies, but modern science puts economic profits in its priority. This leads to a growing concern about social responsibility and professionalism ethics of companies, sponsors and scientists. Specifically, there is no way to control conflicts of participants’ welfare with economic profits, leading to simply relying on individual ethics, social responsibilities and audit. This paper helps relevant agencies and people involved understand conflict of interest. Also this study presents the guidelines as well as independence, autonomy, ethical imagination and phronesis required for scientists.
        27.
        2013.09 KCI 등재 서비스 종료(열람 제한)
        This study was performed to evaluate the effects of fibroblast co-culture on in vitro maturation (IVM) of prepubertal mouse preantral follicles. The intact preantral follicles were obtained from the ovaries of 12-14 day old mice and these were cultured individually in α-minimal essential medium (α-MEM) supplemented with 5% fetal bovine serum (FBS), 100 mIU/㎖ recombinant follicle stimulating hormone (rFSH), 1% insulin-transferrin-selenium, 100 μg/ml penicillin and 50 ㎍/㎖ streptomycin as base medium for 12 days. A total of 200 follicles were cultured in base medium co-cultured with mouse embryonic fibroblast (MEF) (MEF group) (n=100) or only base medium as control group (n=100). Survival rate of follicles on day 12 of culture were significantly higher in the MEF group of 90.0%, compared with 77.0% of the control group (p=0.021). Follicle diameters on day 6 and 8 of the culture period were significantly larger in the MEF group than those in the control group (p=0.021, p=0.007, respectively). Estradiol levels in culture media on day 4, 6, 8, 10 and 12 of the culture period were significantly higher in the MEF group (p=0.043, p=0.021, p=0.006, p<0.001 and p=0.008, retrospectively). Our data suggest that MEF cell co-culture on IVM of mouse preantral follicle increases survival rate and promotes follicular growth and steroid production.
        28.
        2013.09 KCI 등재 서비스 종료(열람 제한)
        This study was performed to investigate the effect of peroxisome proliferators activated receptor-r (PPAR-r) ligand, pioglitazone, on production of regulated upon activation normal T-cell expressed and secreted (RANTES) and in vitro fertilization (IVF) outcome in infertile patients with endometriosis. Sixty-four infertile patients with stage III or IV endometriosis undergoing IVF were randomly allocated to the study or the control group. The long protocol of GnRH agonist (GnRH-a) was used for controlled ovarian stimulation (COS) in all patients. Patients in the study group were treated with pioglitazone at a dose of 15 ㎎/day orally from the starting day of GnRH-a treatment to the day of hCG injection. Blood samples were drawn for serologic assay of RANTES on the first day of GnRH-a treatment and the day of hCG injection. There were no differences between the study and control groups in patient characteristics. There were also no differences between the two groups in COS duration, and the numbers of retrieved oocytes, fertilized oocytes and embryos transferred. The clinical pregnancy rate per cycle was higher in the study group, but this difference was not statistically significant. However, embryo implantation rate was significantly higher in the study group of 12.5% compared with 8.6% in the control group (P<0.05). The serum RANTES levels after pioglitazone treatment were significantly lower than those before pioglitazone treatmen in the study group (P<0.05). Our data suggest that pioglitazone treatment can suppress RANTES production and improve the embryo implantation rate in patients with endometriosis undergoing IVF.
        29.
        2013.07 서비스 종료(열람 제한)
        Phosphorus is one of the macronutrients essential for plant growth and development, as well as crop productivity. Many soils around the world are deficient in phosphate (Pi) that plants can utilize. To cope with the stress of Pi starvation, plants have evolved many adaptive strategies, such as changes of root architecture and enhanced Pi acquisition form soil. To understand molecular mechanism underlying Pi starvation stress signaling, we characterized the activation-tagged mutant showing altered responses to Pi deficiency compared to wild type Arabidopsis and named hsp3 (hypersensitive to Pi starvation3). hsp3 mutant exhibits enhanced phosphate transporter activity, resulting in higher Pi content than wild type. However, in root architectural change under Pi starvation, hsp3 shows hyposensitive responses than wild type, such as longer primary root elongation, lower lateral root density. Histochemical analysis using hsp3 mutant expressing auxin-responsive DR5::GUS reporter gene, indicated that auxin allocation from primary to lateral roots under Pi starvation is aborted in hsp3 mutant. Molecular genetic analysis of hsp3 mutant revealed that the mutant phenotype is caused by the lesion in ENHANCED SILENCING PHENOTYPE4 (ESP4) gene whose function is proposed in mRNA 3’ end processing. Here, we propose that mRNA processing plays a crucial role in Pi homeostasis in Arabidopsis.
        30.
        2013.07 서비스 종료(열람 제한)
        FLOWERING LOCUS T (FT) is major determinant of the length of the vegetative phase in plants. To understand the role of FT homologs in flowering time control of soybean, we identified ten soybean FT genes and named GmFTs. Expression analysis of GmFT homologs showed that the transcripts of most FT clade genes are mainly expressed in leaves. The expression of GmFT2a, GmFT2b, GmFT5a, and GmFT6 strongly induced in response to floral inductive short-day condition, but GmFT4 and GmFT6 exhibited opposite expression pattern. To understand the biological function of each GmFT/TFL1 genes in flowering time control, we ectopically expressed GmFT cDNAs in Arabidopsis under the control of CaMV 35S promoter. Interestingly, while 35S:GmFT2a and 35S:GmFT5a transgenic plant showed extremely early flowering phenotype, overexpression of GmFT4 delayed flowering. Furthermore we analyzed expression patterns GmFT genes in the leaves of Korean soybean landraces showing various flowering time. The results showed that the transcript level of two FT homologs, GmFT2a and GmFT5a, was high in early flowering landraces, but low in late flowering landraces. In contrast, GmFT4 exhibited opposite expression pattern to those of GmFT2a and GmFT5a, suggesting that GmFT4 may function antagonistically to GmFT2a and GmFT5a in flowering time control of soybean. These results demonstrated that soybean FT homologs have both unique and conserved functions in the photoperiodic control of flowering compared with those in Arabidopsis.
        31.
        2011.09 KCI 등재 서비스 종료(열람 제한)
        The immature embryos during seed development were examined to predict the suitable embryos for an efficient regeneration system. Five spring wheat genotypes and five winter wheat genotypes were tested using immature embryos as explants. Spring wheat genotypes showed much higher levels of plant regeneration than those of winter wheat genotypes. The highest frequencies of embryogenesis and regeneration were obtained when embryos at 13-14 days after anthesis (DAA) were used as explant and decreased using embryos at 21-22 DAA during seed development. Significant differences were also found for callus induction and regeneration as affected by immature embryo size. The regeneration efficiency was drastically decreased in spring and winter wheat genotypes when embryos larger than 2.0 mm of length were used. The optimum developmental stage and embryo length for regeneration efficiency were at 13-14 DAA and 1.0-1.5 mm, respectively. The selection of suitable embryos for the high frequencies of embryogenesis and regeneration leads us to efficient genetic improvement of wheat.
        32.
        2009.09 KCI 등재 서비스 종료(열람 제한)
        Mature dry seeds of Korean cultivars, Daepungkong, Muhankong, Myeongjunamulkong, Somyeongkong, Sowonkong, Jinpumkong, and Pungsannamulkong were used. The influence of antibiotics on elimination of Agrobacterium growth and shoot regeneration was estimated with cotyledonary node. Cefotaxime and timentin at the concentration of 250 and 500 mg/l suppressed Agrobacterium, especially cefotaxime was an efficient antibiotic to suppress Agrobacterium in all cultivars. While carbenicillin and timentin at the concentration of 50 and 100 mg/l were not sufficient to control the development of Agrobacterium, respectively. Cefotaxime and timentin represented high shoot formation rates compared with carbenicillin. Carbenicillin at low concentrations did not effectively suppress Agrobacterium and also had no effect on shoot development. Cefotaxime at the concentration of 250 mg/l showed maximum frequency of shoot regeneration in cvs. Somyeongkong and Sowonkong. Furthermore, on medium containing cefotaxime, shoot was more quickly formed than the other antibiotics. The use of cefotaxime was very useful for elimination of Agrobacterium growth with cotyledonary node of Korean soybean cultivars.
        33.
        2008.10 KCI 등재 서비스 종료(열람 제한)
        The puroindoline genes (Pina and Pinb) losely linked on the short arm of the 5D chromosome (Hardness locus (Ha)) of hexaploid wheat (Triticum aestivum L.) are of great importance to wheat and product quality. In this study, the barley cultivar Harrington was transformed with wheat gene pina and pinb by particle bombardment and performed in order to develop softer barley lines. The result, an efficiency of 3.9% of the bombarded calli regenerated transgenic plants. Each transgenic event was obtained from the callus of a different immature embryo. They showed the multiple shoots compared with control (no bombardment). Two plants from T0 lines were PCR positive for only the 'soft type' pinb transgene, 10 plants were positive for the 'soft type' pina transgene only, whereas they did not show both 'soft type' pina and pinb transgene. These results supply more evidence to support the hypothesis that puroindolines are potential genes for barley grain hardness and used to be suitable target for the production of transgenic barley plants to their availability biolistic transformation system.
        34.
        2005.12 KCI 등재 서비스 종료(열람 제한)
        Mature embryos were aseptically excised with a scalpel and sliced in fragments measuring 0.5 mm in diameter (sliced mature embryo fragment; 4 ~~ 5 fragments/one embryo). Sliced mature embryo fragments of six wheat cultivars were cultured to develop an efficient method of callus induction and plant regeneration. Callus derived from sliced mature embryo fragments showed a good capacity to embryogenesis and regeneration. Furthermore sliced mature embryo fragments decreased contamination from fungi and bacteria. The high efficiency of callus induction were obtained Keumkangmil and Bob­white. For plant regeneration, selected embryogenic calli were transferred to two types regeneration media. An average number of green spots per callus was 4 to 5 in regeneration media after about one week. Percentage of plant regeneration showed high in regeneration medium containing 0.1 mg/l 2,4-D and 5 mg/l zeatin. Especially, Keumkangmil (27.5~% ) and Bobwhite (33.3~% ) showed high regeneration efficiency. This regeneration system from sliced mature embryo fragments may provide an effective and convenient explant for plant transformation studies
        35.
        2004.12 KCI 등재 서비스 종료(열람 제한)
        The effects of sonication and vacuum infiltration on transformation efficiency was investigated by using immature embryos of Korean wheat as explants. Two Agrobacterium tumefaciens strains, KYRT1 and EHA105, carrying pCAMBIA 1305.1 were used. Transformation efficiency was demonstrated by the detection of β-glucu-ronidase (GUS) activity. GUS expression showed clear difference among Korean wheat cultivars. Geurumil showed higher GUS expression efficiency 79.1~% compared with other cultivars. The effects of the duration of vacuum infiltration and sonication treatment showed a tendency high GUS expression efficiency by their combination. In comparison with other Agrobacterium strains, KYRT1 showed high efficiency in most Korean cultivars.
        36.
        2004.09 KCI 등재 서비스 종료(열람 제한)
        Mature embryo and leaf base segment of Korean oat were used as materials in an experiment to check plant regeneration efficiency. MS media supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D), kinetin, and picloram were used for callus induction from mature embryos and leaf base segments. Three mg/l of 2,4­D and 3 mg/l of picloram in callus induction medium showed high frequency for plant regeneration from mature embryos. Leaf base segments were transferred to callus induction medium and incubated at 25~circC in 16/8 hr light/dark cycle for 3 weeks. Callus induction from leaf base segments of Malgwiri showed high efficiency in medium containing 3 mg/l of 2,4-D and 1 mg/l of kinetin (91.8~%) . In case of Samhangwiri, the combinations of phytohormones did not show significant difference. Regeneration from leaf base segments showed high frequency in shoot medium containing 1 mg/l of antiauxin, tri-iodobenzoic acid (TIBA) and 1 mg/l of 6-benzyladenine (BA). Calli induced from leaf base segments of Samhangwiri and Malgwiri in media containing 3 mg/l of 2,4-D and 3 mg/l of picloram showed high regeneration frequency. It appears that the callus initiation medium may be an important factor for subsequent plant regeneration.
        37.
        2002.12 KCI 등재 서비스 종료(열람 제한)
        Mature embryos of five oat genotypes were cultured to develop an efficient method of callus induction and plant regeneration. Murashige and Skoog(MS) and N6 media supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin were used for callus induction. Percentage of callus induction showed significant among the combinations of plant growth regulators. Callus induction showed high efficiency in medium containing 3 mg/~ell of 2,4-D. The high frequency of callus induction was obtained in Gwiri37. For plant regeneration, calli induced from mature embryos were transferred onto MS and N6 media supplemented with combinations of 6-benzyladenine (BA) and naphthaleneacetic acid (NAA) for 5 weeks. Percentage of plant regeneration showed high in MS medium containing 0.2 mg/~ell of NAA and 1 mg/~ell of BA. The callus initiation medium affected the subsequent plant regeneration. Treatment with 3 mg/~ell of 2,4-D, and 3 mg/~ell of 2,4-D and 3 mg/~ell of kinetin in callus induction media showed high frequency for plant regeneration. Plant regeneration frequency among the genotypes showed significant. Especially, Gwiri37 showed high regeneration frequency. Regenerated shoots were treated with 200, 350 and 500 mg/~ell of indole-3-butyric acid (IBA) transferred onto half-strength MS medium without plant growth regulators. Treatment of shoots with IBA induced root formation rapidly
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