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        검색결과 30

        3.
        2018.11 구독 인증기관·개인회원 무료
        The deleted in azoospermia like (DAZL) gene has been identified in many vertebrate species. DAZL shows high homology with deleted in azoospermia (DAZ) genes that identified only in humans, great apes and Old World monkeys, and boule homolog (BOLL) that identified in many vertebrate species. These genes encode RNA binding proteins (RBP), which regulate the post-transcriptional functions of several genes. In humans, DAZ copies are linked to Y chromosome, while DAZL and BOLL are linked to chromosomes 3 and 2, respectively. DAZ copies has been reported to express in prenatal and postnatal germ cells, particularly in the premeiotic spermatogonia. BOLL has been reported to express during the meiotic G2/M transition in germ cells. DAZL has been reported to express in all stages of germ cells. Compared to humans and mice, the detailed functionalities of DAZL is not clear in many vertebrate species. In our studies, we use chickens as an animal model to examine the expression profiling of DAZL gene in germ cells right from the early embryonic development to the adult. Also, we are studying the effects of small interfering RNA (siRNA) mediated knockdown of DAZL and Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/CRISPR associated protein 9 (CRISPR/Cas9) mediated knockout of DAZL in the chicken primordial germ cells (PGCs). In the chicken, DAZL is linked to chromosome 2 (2p1.3-p1.2), and encodes a 289 amino acids protein. By in situ hybridization, we detected a strong expression of DAZL in the germ plasm of chicken oocytes. Later, the expression of DAZL was strongly detected in all stages of intrauterine development and post-ovipositional development especially in the PGC specifying cells. Moreover, the expression of DAZL was strong and constant in the male and female germ cells until adult stage. The siRNA mediated knockdown of DAZL significantly reduced the PGCs proliferation and increased the apoptosis in vitro. We examined the knockout efficiency of DAZL using CRISPR/Cas9 technique in chicken DF1 fibroblast cell line, prior to test in the PGCs. The results of T7 endonuclease I (T7E1) assay and subsequent sequencing indicates clear mutations on the DAZL gene in DF1 cells, and the method could be applicable to cause mutations on the DAZL gene in PGCs. In conclusion, chicken DAZL express in all stages of germ cells as a germ line marker, and alteration in the gene expression causes germ cells impairment.
        6.
        2011.06 구독 인증기관 무료, 개인회원 유료
        The dissemination process of agricultural research and development (R&D) results has somewhat different characteristics from that of typical R&D results. However, these characteristics are not adequately considered on the basis of an examination of the current performance system, the resulting management plans, and strategies for the application and dissemination of the results of agricultural R&D in Korea. The performance evaluation indicator exposed the problem of the inadequate consideration of the characteristics of each of these areas, particularly the lack of unified R&D-related institutions and the inadequacy of the system to monitor outcomes. To address these shortcomings in the agricultural R&D programs in Korea, the policies pertaining to agricultural R&D performance, results management, and dissemination in the U.S. and Japan were examined. Based on these investigations, we proposed strategies to improve the agricultural R&D policies in Korea.
        6,900원
        15.
        2017.07 KCI 등재 서비스 종료(열람 제한)
        We analyzed how foraging area use changed in female Pipistrellus abramus during the breeding season. Radio tracking was used to follow 12 female P. abramus in Gyeongju City, from 2013 to 2015. We followed three bats in each of four stages of reproduction: early pregnancy, late pregnancy, lactation, and post-lactation. Our data showed that the usable area of a foraging site and the area that was actually used by bats in that site were different, and foraging site use also differed according to stage of reproduction. The bats used arable land the most, with use rates of 57%, 40.4%, and 73.2% during early pregnancy, late pregnancy, and lactation, respectively. Bats in a post-lactation state did not use arable areas at all and instead foraged over bodies of water 90% of the time. There was no difference in the use of each foraging environment between bats in early pregnancy and late pregnancy. However, bats in late pregnancy and those that were lactating did use arable land to different extents, and bats that were lactating and those that were post-lactation also used arable land and bodies of water to different extents.
        16.
        2013.07 서비스 종료(열람 제한)
        Alfalfa (Medicago sativa L.) is one of the most important forage crops in the world and it’s has been known as the best feed materials for dairy cows and other high valued animals. The new uses of alfalfa are being explored as bio-energy, food, medical and biochemical uses. R2R3-type MYB transcription factors play important roles in transcriptional regulation of anthocyanin biosynthesis. The R2R3-type IbMYB1 is known to be a key regulator of anthocyanin biosynthesis in the storage roots of sweetpotato. We previously showed that the expression of IbMYB1a led to anthocyanin pigmentation in tobacco and Arabidopsis. In this study, we generated transgenic alfalfa plants expressing the IbMYB1a gene under the control of CaMV 35S promoter. Overexpression of IbMYBa in transgenic alfalfa produced strong anthocyanin pigmentation in seedlings and generated a deep purple color in leaves, stems, roots, and even in seeds. High performance liquid chromatography (HPLC) analysis revealed that IbMYB1a expression led to the production of cyanidin as a major core molecule of anthocyanidins in alfalfa, as occurs in the purple leaves of sweetpotato (cv.Sinzami). We also examined expression of several structural genes in the anthocyanin biosynthetic pathway in alfalfa by RT-PCR analysis. In this presentation, we will further present molecular and biochemical characterization in IbMYB1a-overexpression lines. This result shows that the IbMYB1a transcription factor is sufficient to induce anthocyanin accumulation in the forage legume alfalfa plants.
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