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        검색결과 551

        401.
        2013.08 서비스 종료(열람 제한)
        DGCR8 is a RNA-binding protein working with DROSHA involved in critical processes for microRNA production in the nucleus. To understand function of miRNAs in the uterus, we have produced uterus-specific Dgcr8 conditional knock-out mice using two well-known Cre mouse models, anti-Mullerian hormone receptor 2 (Amhr2)-Cre and progesterone receptor (PR)-Cre. Dgcr8flox/flox;PRcre/+ mice were mainly analyzed and considered as uDgcr8 KO in this study unless otherwise indicated as Dgcr8flox/flox;Amhr2cre/+ mice. Morphological and histological analyses, embryo cultures, genomic DNA PCR, realtime RT-PCR and Western blotting were performed. uDgcr8 KO females bred with fertile males did not produce any offspring, suggesting that these mice are infertile. Vaginal smear analyses showed that these mice do not undergo estrous cycle, whereas Dgcr8flox/flox;Amhr2cre/+ mice exhibited regular estrous cyclicity. In vitro culture of 2-cell stage embryos and histological analyses for CL in uDgcr8 KO demonstrated that they can respond to gonadotrophins to ovulate healthy oocytes with comparable fertilization potentials as compared to those in Dgcr8flox/flox mice (Control). Gross morphology, histology, and weight of uteri of uDgcr8 KO mice were similar to those of control at 3-week-old stage. However, uterus become extremely thinner and shorter from 4-week-old stage onward. Histological examination showed significant reduction in gland numbers and stromal area from 4-week-old stage. Interestingly, this phenotype is reflected by significant increase of PR expression in the uteri of 4-week-old mice. In addition, stromal cell proliferation of uDgcr8 KO is severely impaired. BrdU incorporation experiments showed that while epithelial cells undergo proliferation by E2 treatment, stromal cells do not incorporate BrdU under the uterine conditions provided with E2+P4. Collectively, these results conclude that microRNAs are essential for uterine stromal cell proliferation in mice.
        402.
        2013.07 서비스 종료(열람 제한)
        Rice is an important model species and one of the most staple crops of the world. The use of rice appropriate promoters suitable for a specific target transgene is important for the control of spatial and temporal transgene expression. To isolate rice tissue-specific promoters, we exploited the potential of whole genome microarrays in 17 stages: callus, germinating seed, leaf, root, the size of the panicles before heading (1, 3, 5, 8, 10, 15, 20, and 22 cm), and the number of days after pollination (1, 3, 5, 11, 21 DAP) using a 300 K Rice Genome Microarray, covering 31,439 genes of the rice. Eight candidate genes for tissue-specific expression were selected in various organs and stage of reproductive development in rice: Histone H4 for constitutive expression, Dehydrin DHN1 for callus-specific expression, germinating seed-specific hypothetical protein, root-specific hypothetical protein, DNA topoisomerase and Retinoblastoma for expression at panicles before heading, heading-specific profiling, and invertase for expression at seed after pollination. Promoter regions of the selected genes were isolated and fused to the β-glucoronidase (GUS) reporter gene, and the constructs were introduced into rice plants. These promoters are highly active in the tissue-specific manner of rice and can be useful for the spatial and temporal enhancement of target gene(s).
        403.
        2013.07 서비스 종료(열람 제한)
        The cultivation of genetically modified (GM) crops has increased due to their economic and agronomic advantages. Before commercialization of GM crops, however, we must assess the potential risks of GM crops on human health and environment. The aim of this study was to investigate the possible impact of Bt rice on the soil microbial community. Microbial communities were isolated from the rhizosphere soil cultivated with Bt rice and Nakdong, parental cultivar and were subjected to be analyzed using both culture-dependent and molecular methods. The total counts of bacteria, fungi, and actinomycetes in the rhizosphere of transgenic and conventional rice were not significantly different. Denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rRNA genes revealed that the bacterial community structures during cultural periods were very similar each other. Analysis of dominant isolates in the rhizosphere cultivated with Bt and Nakdong rice showed that the dominant isolates from the soil of Bt rice and Nakdong belonged to the Proteobacteria, Cloroflexi, Actinobacteria, Firmicutes, and Acidobacteria. These results indicate that the Bt rice has no significant impact on the soil microbial communities during cultivation period. Further study remains to be investigated whether the residue of Bt rice effect on the soil environment.
        404.
        2013.07 서비스 종료(열람 제한)
        Copy number variations (CNVs) are considered major sources of genetic variation, and CNVs may influence phenotypic variation and gene expression. To detect CNVs, rice seeds were exposed with 100~400 Gy of gamma-ray (GA, 60Co), cosmic-ray (CR) by Russia ISS, and 30 and 40 Gy of ion beam (IB, 220 Mev carbon ion). After the exposed rice seeds were cultured in 1/2 MS medium for 14 days, they were used for array-based Comparative genomic hybridization (CGH) analysis using Agilent’s RICE CGH array. As a results, the highest number of CNVs (Gain 808 and Loss 24,080) were detected in the CR treatment, whereas GA100 (100 Gy of GA) was identified the least CNVs. Compared individual chromosome, the chromosome 8 and 11 were identified the highest CNVs, the chromosome 3 had the least CNVs. Most of identified CNVs existed in the range of 10~500kb. In particular, the same CNV locations among different types of ionizing radiation were observed in chromosome 12, and these CNVs contained the commonly 5 amplified genes, containing retrotransposon protein, NADH-ubiquinone oxidoreductase chain 3, heavy metal transport/detoxification protein domain containing protein, and 2 unknown proteins. Other studies were reported that Ty1 (Long Terminal Repeat-retrotransposon family 1) transcription and retrotransposition were induced by different environmental stresses such as ionizing radiation, UV-light exposure, DNA damage and nutrient starvation in Saccharomyces cerevisiae. Our results also show that retrotransposon protein (LOC_Os12g34016) was specifically amplified by different types of ionizing radiation.
        405.
        2013.07 서비스 종료(열람 제한)
        To determine the expression levels of genes related to the salt stress response in rice, gene expression profiles were investigated through microarray analysis using the rice mutant line Till-II-877. There were no significant changes in physiological response under salt stress of the mutant increased less than that in the WT. The intensity of gene expression was analyzed and compared between the wild type and mutant lines using a microarray. Among the most significantly affected pathways, α-linolenic acid metabolism and linoleic acid metabolism (in lipid metabolism), fructose and mannose metabolism and glycolysis-gluconeogenesis (in carbohydrate metabolism), cysteine and methionine metabolism (in amino acid metabolism), and carbon fixation (in the energy metabolism of photosynthetic organisms) showed changes in gene expression levels under salt stress. These results further our understanding of the effects of salt stress in rice and may aid in the development of salt-tolerant rice cultivars.
        406.
        2013.07 서비스 종료(열람 제한)
        Soluble sugar content in soybean seed is an important quality attribute for soyfood and feed. Usually, soluble sugars comprise 6 to 17% of total dry wt. in mature soybean seeds. In this study, 414 soybean mutant lines induced by gamma-ray were screened by colormetric assay, FACE (Fluorophore-assisted carbohydrate electrophoresis), and GC-MS to identify the change of soluble sugar contents. Among 414 soybean mutant lines, 12 mutant lines derived from three different soybean cultivars (Hwanggum, Paldal, and Bangsa) showed higher level of soluble sugar content compared to their original cultivars. However, 5 mutant lines derived from soybean landrace KAS 636-15 showed lower level in the colormetric assay. In FACE, 17 soybean mutant lines selected by colormetric assay also showed different band intensity compared with their original cultivars. However, there were no different soluble sugar patterns between soybean original cultivars and mutant lines. Finally, the variations of soluble sugar content in 17 soybean mutant lines were confirmed by using GC-MS. These mutant lines will be used for genetic study to find mutations of genes related soluble sugar biosynthesis.
        407.
        2013.06 KCI 등재 서비스 종료(열람 제한)
        This study aims to examine the actual status of the urban heat island in Daegu by analyzing the data of 17 automatic weather stations installed in the Daegu area. And the results can be summarized as follows: First, regarding the temperature distribution in Daegu by summer time zones, for the 31 days(August 1st till 31st), 18 days showed daily maximum temperature over 30℃, and 11 days indicated daily minimum temperature over 25℃. The day that showed the highest daily maximum temperature was August 5th, which indicated 36℃. Second, about the spatial distribution of time ratio exceeding 30℃and 25℃, the area with the highest time ratio exceeding 30℃is mostly the downtown(central area), eastern area, and northern area. Meanwhile, regarding the time ratio exceeding 25℃, the downtown area centering around the central area were high as over 70%, and the outskirts were low as under 65%. Third, considering the temporal distribution of daily maximum temperature and daily minimum temperature, daily maximum temperature was shown around 14:00 to 15:00 while the daily minimum temperature was indicated around 17:00 to 18:00. Daily maximum and minimum temperature were appeared at northeast and downtown, respectively. Fourth, regarding the spatial distribution of tropical days and tropical night days, tropical days showed 77%and tropical night days indicated 42% before and after the 24th and also the 13th each. Tropical days were occurred up to 24 days at northeastern area. And the southwestern area of Daegu showed under 22 days. The downtown showed the 14 days of the tropical night. However, the outskirts indicated relatively few days as under 10 days. Fifth, about the spatial distribution of the average daily temperature range (the difference between the highest temperature and lowest temperature), the central area, the central part of the city, showed the smallest as 7.2℃, and as it was closer to the northern area, it became larger, so in the eastern and northern area, it was over 8.8℃or so.
        411.
        2013.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        ARGO-M is a satellite laser ranging (SLR) system developed by the Korea Astronomy and Space Science Institute with the consideration of mobility and daytime and nighttime satellite observation. The ARGO-M optical system consists of 40 cm receiving telescope, 10 cm transmitting telescope, and detecting optics. For the development of ARGO-M optical system, the structural analysis was performed with regard to the optics and optomechanics design and the optical components. To ensure the optical performance, the quality was tested at the level of parts using the laser interferometer and ultra-high-precision measuring instruments. The assembly and alignment of ARGO-M optical system were conducted at an auto-collimation facility. As the transmission and reception are separated in the ARGO-M optical system, the pointing alignment between the transmitting telescope and receiving telescope is critical for precise target pointing. Thus, the alignment using the ground target and the radiant point observation of transmitting laser beam was carried out, and the lines of sight for the two telescopes were aligned within the required pointing precision. This paper describes the design, structural analysis, manufacture and assembly of parts, and entire process related with the alignment for the ARGO-M optical system.
        412.
        2012.09 서비스 종료(열람 제한)
        Early growth response 1 (Egr1) is an immediate early response gene which is induced by various external stimuli and acts as transcription factor to direct second-wave gene expression leading to cell growth, differentiation and/or apoptosis. It is well known that Egr1 regulates transcription of a cluster of genes in cancers and luteinizing hormone (LH) beta subunit in the pituitary. In addition to function of Egr1 in cancers and pituitary, we recently showed that Egr1 acts as a local master regulator to mediate estrogenic actions in the uterus. However, regulatory mechanism by which Egr1 directs transcription of its downstream target genes in the uterus remains to be yet explored. Thus, we have tried to identify direct target genes of Egr1 in the uterus by analyzing mRNA microarray data sets followed by in silico promoter analyses with chromatin immunoprecipitation (CHIP). mRNA expression profiles of Egr1(-/-) uteri and Egr1(-/-) ovaries were compared to those of wildtype mice to provide a potential list of direct target genes of Egr1 in the uterus. Whereas Egr1 is rapidly and transiently induced in the ovary and the uterus by external stimuli, LH and estrogen, respectively with a similar manner, a list of differentially expressed genes between Egr1(+/+) and Egr1(-/-) mice were barely overlapped between these two datasets. This result suggests that the transcriptional network of Egr1 in the uterus is quite different from that in the ovary. The list of differentially expressed genes in Egr1(-/-) uterus was enriched by RT-PCR. In silico analyses with MatInspector provided evidence that Egr1 binding sites are relatively enriched in -500 bp promoter regions of genes in the list. CHIP assays for Egr1 antibody with uterine tissues 2 h after estrogen treatment reinforced the possibility that genes identified in this study such as Gadd45g and Lbh could be directly regulated by Egr1 in uterine context. Collectively, we show that bioinformatic analyses of expression profiles with in silico analyses could be a useful tool to enrich potential candidates of direct target genes of transcription factors.
        413.
        2012.09 서비스 종료(열람 제한)
        Early growth response 1 (Egr1) belongs to the Egr family of zinc finger transcription factors that regulates cell growth, differentiation, and apoptosis. Egr1(-/-) female mice are infertile due to anovulation resulting from luteinizing hormone β subunit (LHβ) deficiency. While it is clear that Egr1 is a critical factor to regulate transcription of LHβ in the pituitary gland, function of Egr1 and mechanisms by which estrogen (E2) and/or progesterone (P4) regulates Egr1 in uterus still remain unexplored. Using multiple approaches, here we have characterized regulatory mechanism of Egr1 induction in the uterus and uterine phenotypes of Egr1(-/-) mice. Eight-week-old female mice were ovariectomized (OVX) and rested for a week. Uteri of OVX mice treated with various concentrations of E2 and/or other hormones were collected at 2h after hormone treatment unless otherwise indicated. Collected uteri were utilized for mRNA microarrays, realtime-RT-PCR, Western blotting, and histological analyses for immunofluorescence and BrdU staining. Egr1 mRNA was rapidly induced with the highest level at 2h after E2 treatment and gradually decreased to basal levels at 12 h. E2-induced phosphorylation of ERK1/2 and AKT, and Egr1 transcription were effectively inhibited by pretreatment of ICI 182,780. Pharmacological inhibition of ERK1/2, but not AKT significantly blocked E2-induced Egr1 expression in the uterus. P4 effectively dampened E2-dependent Egr1 transcription and its antagonistic effects were partially interfered with RU486 pretreatment. Interestingly, BrdU incorporation experiments provided evidence that epithelial cells undergo hyperproliferation in Egr1(-/-) mice. This is consistent with microarray data that several key factors for cell cycle progression such as cyclin Ds and E2F1 are overexpressed in these mice. Furthermore, in the uteri of OVX Egr1(-/-) mice treated with E2+P4, stromal cell proliferation is severely impaired and epithelial cells persistently proliferating. While ovulation, fertilization and embryo development normally occur in Egr1(-/-) mice treated with a superovulation regime to rescue LH deficiency, embryo implantation is severely impaired. Blastocysts were not able to implant even on day 6 of pregnancy in Egr1(-/-) mice. In addition to embryo implantation, uterine response to artificial decidualization in hormone-primed Egr1(-/-) OVX mice was relatively less than that of wildtype mice. Collectively, our results show that Egr1, which is rapidly induced by E2-ER-ERK1/2 pathways, is a critical factor to control E2-dependent cell proliferation via regulation of a spectrum of genes for embryo implantation in the uterus.
        414.
        2012.07 서비스 종료(열람 제한)
        Brown leaf spot, caused by necrotrophic Cochliobolus miyabeanus (imperfect; Bipolaris oryzae), is one of the devastating disease in rice (Oryza sativa). Especially, recommended agricultural system such as diminishing fertilizer and environmental alteration like temperature increment result in the favorable conditions for the outbreak of this disease. Lack of water supply also requires drought-tolerant rice cultivar. We hypothesized that regulation of programmed cell death (PCD) should be a common solution conferring resistance and tolerance against above biotic and abiotic stresses at the same time. Among 17 CYCLIC NUCLEOTIDE-GATED ION CHANNEL in rice (OsCNGCs), over expression of a CNGC resulted in lesion mimic phenotypes in Dongjin background. Further, knock out of a CNGC resulted in enhanced resistance against rice brown spot in the field. These results indicate that selected OsCNGC should be involved in the PCD regulation and fungal infection-specific regulation of OsCNGC expression might induce resistance against rice brown spot because of pathogen’s necrotrophic nature. Vitamin E, tocopherol, is involved in the accumulation inhibition of reactive oxygen species involving superoxide and hydrogen peroxide. Tocopherol cyclase in Nicotiana benthamiana (NtTC), which is included in tocopherol systhesis, conferred tolerance against drought stress to rice. We already have settled down the recombination system effectively removing selection markers in vector. Based on these systems, we will define fungal secretome and genome, confirmation of PAMPs/effectors, identification of rice pattern recognition receptor, and functional characterization of these rice genes in the respect of PCD and disease resistance. We will also develop marker-free transgenic rice tolerant to drought and/or salinity stresses. These works should give us a bundle of rice genes conferring resistance and tolerance against biotic and abiotic stresses and amount of information useful for the analyses of common cross talk points between disease resistance and stress-tolerance.
        415.
        2012.07 서비스 종료(열람 제한)
        Calcium-binding proteins, like calcineurin B-like (CBL) proteins, represent important roles in plant calcium signaling. Calcium signals mediate a multitude of plant responses to external stimuli and regulate a wide range of physiological processes including pathogens, abiotic stresses and hormones. These proteins form a complex network with their target kinases being the CBL-interacting protein kinases (CIPKs). CBL genes play vital roles in multiple abiotic stress response pathways whereas some of these are more specifically involved in mediating ABA signaling. In this study, we collected 17 CBL genes designated as B. rapa CBL (BrCBL) from the Brassica database and analyzed the sequences. In comparison analysis, these genes showed high homology with published CBL genes of other species. An organ specific expression of these genes was observed in different organs of chinese cabbage plants. In addition, six BrCBL genes showed responsive expression after cold and drought stress treatments at certain time courses. All these data revealed that these CBL genes might be useful resources in developing abiotic stresses resistance Brassica.
        416.
        2012.07 서비스 종료(열람 제한)
        A Transgenic Kimch cabbage has been developed harboring T-DNAs expressing delta-endotoxin insecticidal protein, herbicide (basta) resistant protein, and antisense transcript of AsMADS2 gene. Three transgenic lines, #24, #45, and #51, originated from the same T0 plant were analyzed in terms of molecular characterization, phenotype, and agronomic traits. Flanking sequence analysis confirmed that T-DNA, with 7132 bp intact structure, was inserted onto the pseudochromosome A10 of B. rapa and all the genes in T-DNA were functionally active. Three of GM cabbage showed 69.2~75.3% of plant height and 81.8~89.7% of diameter to those of the isogenic variety ‘Nowon’, respectively. Curving upward leaf lamina attitude was observed on GM cabbage, while straight or slight concave on non-GM cabbage. In addition, an average range of 86~91.5% of head height and 87.4~94.8% of head diameter were observed on GM cabbage to those of the isogenic variety ‘Nowon’, respectively Moreover, curled inwards or slight overlap of head-forming leaf overlap at terminal region was observed on GM cabbage, but curled outwards or erect on non-GM cabbage. AsMADS2, a transcription factor reported to be involved in early flowering, was stably expressed to RNA in the GM cabbage, but it was not shown the significant influences to flowering time.
        417.
        2012.07 서비스 종료(열람 제한)
        The surveying of binding affinity between a particular transcription factor and DNA motifs is important in order to understand the developmental specific gene expression and regulatory networks of an organism. The microarray-based technologies (protein-binding microarrays; PBMs) provide useful predictions for understanding the transcriptional regulatory code in a genome-wide manner. The PBM was designed in such a way that target probes were synthesized as quadruples of all possible 9-mer combinations, named Q9-UPBM. Also, we developed rice promoter PBM (RPBM) using 19,480 rice promoter sequences containing 40 bp long probe with overlapping 20 bp (cover 1kb from 5’ upstream). We applied RISBZ1 protein, an endosperm specific basic leucine zipper transcription factor, to compare binding site specificities between Q9-UPBM and RPBM and find directly regulated promoter regions through the RPBM. Several cis-elements; Prolamin box (TGTAAAG), GCN4 motif (TGA(G/C)TCA), AACA motif (AACAAAA), and ACGT motif, are highly conserved in the promoters of cereal seed storage protein genes, and play a central role in controlling endosperm specific expression during seed maturation. Characterization of cis-elements and TFs has been performed on many storage protein genes of several crop plants, but the mechanisms are still poorly understood. Two chips provide RISBZ1 could bind to ACGT motif such as a CCACGTCA site and GGATGAC site as well as GCN4 motif known binding site. In RPBM binding affinity to CCACGTCA was highly significant, compared to GGATGAC site. The difference might be caused by the biased presence of specific promoter rather than Q9-UPBM. Also our results will provide direct insight into the importance of combinatorial interplay between cis-elements in regulating the expression of seed storage protein genes.
        418.
        2012.07 서비스 종료(열람 제한)
        Regulations in the EU, Japan, Korea, etc. require that foods and feeds made of or derived from genetically modified organisms (GMOs) should be approved and labeled according to a threshold. Recently, disease resistant transgenic rice was developed in Korea, which resulted from the transformation events involving choline kinase gene, OsCK1. In order to monitor unintended release of the developed GM rice in the near future, as well as to meet GM-labeling requirements, the development of a reliable method for detection of disease resistant GM rice is requisite. Here, specific primer pairs for the detection of GMO was designed on the basis of a introduced gene and the flanking junction sequences between a plant DNA and a integrated gene construct, and also SPS gene was used as an endogenous reference material. Specificities of all designed primers were tested through qualitative PCRs. Clearly, target specific amplicons could be detected from disease resistant GM rice event. In addition, the limits of detection (LOD) using the event-specific primers were approximately 0.1% for the disease resistant GM rice line. This result indicated that the developed detection method is suitable for the traceability of disease resistant GM rice, because of using the primer specifically corresponded to the junction site between plant genomic DNA and inserted DNA. Keywords: genetically modified organisms, disease resistant GM rice, PCR detection, event-specific primer
        419.
        2012.07 서비스 종료(열람 제한)
        Rice seed storage proteins (SSPs) are accumulated in storage organelles of the endosperm during seed maturation. The SSPs from the rice seeds consist of glutelins as a major SSP, and prolamins and globulins comprise about the rest 20 % of the SSPs. To improve the nutritional quality of rice seeds or processing properties of rice flour, we are attempting to change the composition of the SSPs in rice seeds. For this purpose, we generated many transgenic rice plants, which show the altered levels of the SSPs, by using the RNA interference (RNAi). Accumulation of glutelins was 76% reduced in the GluA-RNAi lines. The Pro-RNAi lines revealed the reduced levels of prolamins to 36%. The protein level of globulins was 61% reduced in the Glb-RNAi lines. Interestingly, an obvious reduction of glutelins, prolamins, and globulins was not examined in the GluA:Pro:Glb-RNAi lines. This suggests that a reduction of a few SSPs could be compensated by the increases of other SSPs at the protein levels. We are also attempting to generate transgenic rice plants expressing both a high-molecular-weight (HMW) glutelin subunit and a low-molecular-weight (LMW) glutelin subunit. These manipulations of rice SSPs might be an important contribution on improving the functional properties of rice seeds.
        420.
        2012.07 서비스 종료(열람 제한)
        To develop a strong root-specific gene expression system, six gene promoters were investigated by using transgenic Arabidopsis and a GUS:GFP reporter gene. These promoters were initially selected from Arabidopsis genes which are specifically expressed only in roots, based on the TIGR information. The GUS activity of these promoters was measured in several tissues of Arabidopsis by using both histochemical and fluorimetric GUS assays. The results showed that the activity of these promoters was strongly detected only roots. This was also confirmed by RT-PCR analysis. Therefore, these six promoters could be used for utilization of a root-specific expression of target genes.