Telomeres are the end of chromosomes and consist of a tandem repeat sequence of (TTAGGG)n and associated proteins. Telomerase is a ribonucleoprotein which act as a template for the synthesis of telomeric DNA. Telomeres are essential for chromosome stability and are related with cell senescence, apoptosis and cancer. Even though telomeres and telomerase have been studied extensively, very little is known about telomere dynamics in embryonic cells. This study was carried out to analyze the telomeres distribution and telomerase activity of chicken cells during embryonic and developmental stages. The target cells for analysing were sperms, ovulated ova, early embryonic cells and the cells from brain, heart, liver, kidney and germinal tissue in fetus. Telomeres distribution on target cells was analyzed by Q-FISH (Quantitation-Fluorescence in situ Hybridization) techniques using a chicken telomere repeat probe. Telomerase activity was performed by TRAP assay (Telomeric repeat Amplification Protocol) with target DNA. In results, the telomeres of chicken were found at the ends of all chromosomes. In addition, chicken had interstitial telomeres on chromosomes 1, 2 and 3. Telomerase activity was highly detectable in early embryonic cells, germinal tissues and kidney cells. Whereas telomerase activity was gradually down-regulated when the organs, including brain, heart, and liver, were developed from embryos. In the distribution of telomeric DNA on the embryonic and developmental stages, most of the cells was gradually decreased in telomere quantity during ontogenesis.

The purpose of this study is to evaluate an efficacy of in vitro differentiated human embryonic stem (hES, MB03) cells expressing Nurr1 in relief of symptomatic motor behavior of Parkinson's disease (PD) animal models MB03 was genetically modified to express Nurr1 protein and was induced to differentiate according to 2-/4+ protocol using retinoic acid and ascorbic acid. The differentiation-induced cells were selected for 10 to 20 days thereafter in N2 medium. Upon selection, cells expressing GFAP, TH, or NF200 were 38.8%, 11%, and 20.5%, respectively. in order to examine therapeutic effects of the differentiated cells in PD animal model, rats were unilaterally lesioned by administration of 6-kydroxydopamine HCI (6-OHDA) into medial forebrain region (MFB, AP -4.4 mm, ML 1.2 mm, DV 78 mm with incision bar set at -2.4 mm), as a reference to bregma and the surface of the skull. Confirmation of successful lesion by apomorphine-induced rotational behavior, differentiated cells were transplanted into the striatum (AP 1.0, ML 3.5, DV -5.0; AP 0.6, ML 2.5, DV -4.5). Improvements of asymmetric motor behavior by the transplantation were examined every two weeks after the surgery. In two weeks, numbers of rotation by the experimental rats were (P<0.05) of the number before transplantation, however, the ratio increased slightly to in six weeks. In contrast, the ratio of sham-grafted animals ranged from 112.3+8.5% to 139.2+28.9% during the examination. Immunohistochemical studies further confirmed the presence, survival, migration, and expression of TH of the transplanted human cells.

Embryonic stem (ES) cells proliferate extensively in the undifferentiated state and have the potential to differentiate into a variety of cell types in response to various environmental cues. The generation of functional dopaminergic neurons from ES cells is promising for cell replacement therapy to treat Parkinson's disease. We compared the in vitro differentiation potential of pluripotent human embryonic stem (hES, MB03) cells induced with basic fibroblast growth factor (bFGF) or retinoic acid (RA). Both types of treatment resulted in similar neural cell differentiation patterns at the terminal differentiation stage, specifically, 75% neurons and 11% glial cells. Additionally, treatment of hES cells with brain derived neurotrophic factor (BDNF) or transforming growth factor (TGF)- during the terminal differentiation stage led to significantly increased tyrosine hydroxylase (TH) expression, compared to control (P<0.05). In contrast, no effect was observed on the rate of mature or glutamic acid decarboxylase-positive neurons. Immunostaining and HPLC analyses revealed the higher levels of TH (20.3%) and dopamine in bFGF and TGF- treated hES cells than in RA or BDNF treated hES cells. The results indicate that TGF- may be successfully used in the bFGF induction protocol to yield higher numbers of functional dopaminergic neurons from hES cells.

Main strategy for a treatment of Parkinson's disease (PD), due to a progressive degeneration of dopaminergic neurons, is a pharmaceutical supplement of dopamine derivatives or ceil replacement therapy. Both of these protocols have pros and cons; former exhibiting a dramatic relief but causing a severe side effects on long-term prescription and latter also having a proven effectiveness but having availability and ethical problems Embryonic stem (ES) cells have several characteristics suitable for this purpose. To investigate a possibility of using ES cells as a carrier of therapeutic gene(s), human ES (hES, MB03) cells were transfected with cDNAs coding for tyrosine hydroxylase (TH) in pcDNA3.1 (+) and the transfectants were selected using neomycin (250 ). Expression of TH being confirmed, two of the positive clone (MBTH2 & 8) were second transfected with GTP cyclohydrolase 1 (GTPCH 1) in pcDNA3.1 (+)-hyg followed by selection with hygromycin-B (150 ) and RT-PCR confirmation. By immune-cytochemistry, these genetically modified but undifferentiated dual drug-resistant cells were found to express few of the neuronal markers, such as NF200, -tubulin, and MAP2 as well as astroglial marker GFAP. This results suggest that over-production of BH4 by ectopically expressed GTPCH I may be involved in the induction of those markers. Transplantation of the cells into striatum of 6-OHDA- denervated PD animal model relieved symptomatic rotational behaviors of the animals. Immunohistochemical analyses showed the presence of human cells within the striatum of the recipients. These results suggest a possibility of using hES cells as a carrier of therapeutic gene(s).

Pluripotent embryonic stem (ES) cells differentiate spontaneously into beating cardiomyocytes via embryo-like aggregates. We describe the use of mouse embryonic stem (mES03) cells as a reproducible differentiation system for cardiomyocyte. To induce cardiomyocytic differentiation, mES03 cells were dissociated and allowed to aggregate (EB formation) at the presence of 0 75% dimethyl sulfoxide (DMSO) for 4 days and then another 4 days without DMSO (4+/4-). Thus treated EBs were plated onto gelatin-coated dish for differentiation. Spontaneously contracting colonies which appeared in approximately 4-5 days upon differentiation. Expression of cardiac-specific genes were determined by RT-PCR. Rebust expression of myosin light chain (MLC-2V), cardiac myosin heavy chain , cardiac muscle heavy polypeptide 7 -MHC), cardiac transcription factor GATA4 and skeletal muscle-specific -subunit of the L-type calcium channel () were detected as early as 8 days after EB formation, but message of cardiac muscle-specific -subunit of the L-type calcium channel (CaCh) were revealed at a low level. Strikingly, the expression of atrial natriuretic factor (ANF) was not detected. When spontaneous contracting cell masses were examined their electrophysiological features by patch-clamp technique, it showed ventricle-like action potential 17 days after the EB formation. This study indicates that mES03 cell-derived cardiomyocytes displayed biochemical and electrophysiological properties of cardiomyocytes and DMSO enhanced development of cardiomyocytes in 4+/4- method.

Research has been in progress for more than a decade to production of useful proteins by genetic modification in cattle. However, the levels of protein production in transgenic cattle have been reported very low. To enhance protein production in transgenic animal, we tried homologous recombination to donor cells for production of transgenic clone cattle through nuclear transfer procedure. Thus, we constructed the two targeting vectors of human thrombopoietin (TPO) at bovine -casein locus using homologous recombination with 13.6 kb and 9.6 kb homology. In two targeting vectors, positive selection was through the neomycin resistance gene and negative selection was by the diphtheria toxin (DT). Gene targeting was attempted in bovine embryonic fibroblasts (bEF) and bovine ear skin fibroblasts (bESF). To determine the most appropriate concentration of neomycin for bEF and bESF, G4l8 resistance was confirmed by culturing the cells in various concentrations of the drug and both of the cells were optimally selected at of neomycin. The transfected bEF and bESF by the targeting vectors were colonized efficiently at the ratio of DNA to transfection reagent such as :2 and :. Comparing number of healthy clones from passage 4 to passage 8, bESF (17%) persist in culture for much longer than bEF (6%). The two gene-targeted bESF clones of 30 random-integrated clones with 9.6 kb homology length were confirmed, however, nothing was out of 72 random integration clones with 13.6 kb homology length, The DT also worked more efficiently in clones transfected with the vector of 9.6 kb homology length. Our data suggests that the choice of donor cell for long culture period should be considered to obtain targeted cell clone, and the gene-targeting frequency and the DT working efficiency are dependent on the length of target homology.

In an effort to uncover the spermatogenic impairment by the polychlorinated biphenyls (PCBs), the expression of tight junctions (TJs) genes important for the formation of the blood testis barrier (BTB) were examined following the 3,3',4,4',5-pentachloro biphenyl (PCB126) treatment in cultured neonatal testis in mice. At 4 days (D4) after 10 and 100 nM PCB126 treatment the expression of claudin-11 was significantly increased when compared with vehicle control. In contrast no difference in occludin and claudin-1 expression was found among the experimental group. On D8, 100 nM PCB126 significantly increased the expression of claudin-11 but not occludin and claudin-1. 1 uM PCB126 treatment significantly decreased expressions of occludin and ciaudin -1, suggesting the general toxic effect on the Sertoli cell. Because PCB126 does not alter the proliferative activity of spermatogenic cells and Sertoli cells in neonatal testis, it is likely that increase in the expression of claudin-11 by low dose of PCB126 may attribute to the alteration of the Sertoli cells differentiation in testis. It also emphasized that PCB126 might have differentially affected the transcription of TJ genes in Sertoli cells. In conclusion, this result suggests that the structure of TJ may be targeted by PCB126 in neonatal testis in mice and that co-PCB is potentially harmful to spermatogenesis by alteration of the development of BTB.

본 연구의 목적은 체육교사의 동기요인과 교수행동 및 학생 학습행동 요인간의 관계를 규명하는데 있다. 연구참여자는 10주간의 교생실습에 참가 한 17명의 예비교사를 목적표집법에 의해 선발하였으며, 각각의 교생 및 학생의 교수-학습행동은 단일피험자 설계에 널리 사용되어지고 있는 행동관찰분석법을 통해서 관찰 및 분석되었다. 본 연구의 결과는 교사의 잠재적 교수행동의 동기점수(MPS)는 교사의 신체적 지도 및 학생과의 비언어적 긍정적 상호작용이라는 교수행동과 비교적 높은 상관관계가 있음을 보여주고 있다. 또한 잠재적 동기점수는 학생의 적절한 수업과제 참여 및 지속빈도와 비교적 높은 상관관계가 있는 것으로 밝혀졌다. 따라서, 본 연구는 예비교사의 교육과정에서 교사의 인지적 변인과 행동변인과의 상관관계를 밝힘으로서, 교수행동의 관찰, 평가 및 교육이라는 측면에 중요한 시사점을 제공하고 있다. 마지막으로, 교사의 인지적 변인과 교수-학습행동의 다양한 측면 및 연계성에 관한, 새로운 연구과제의 필요성과 타당성을 제시하고 있다.

본 연구의 목적은 자기 모델링 기법을 통한 교수행동변화를 알아보고, 교생의 교수행동에 대한 구체적 자료를 체계적으로 관찰, 제시하는데 있다. 연구대상은 중·고등학교 체육교생 4명(남자 3, 여자 1)으로 선정하였고, 연구기간은 교생실습기간(참관학습 1주를 제외) 3주간에 걸쳐 이루어졌다. 관찰된 교수단원은 구기종목(농구, 소프트볼)과 체조(무용), 육상(단거리 달리기, 멀리뛰기)이었다. 교생의 교수행동은 소형 비디오 카메라를 이용한 비디오촬영과 Sharpe와 Koperwas(2001)에 의해 개발되어진 행동분석 관찰프로그램인 컴퓨터 소프트프로그램(BEST)을 이용하여 관찰 분석되었다. 수집된 교생교수 행동 자료는 빈도와 강도(지속시간)에 의해서 분석되었고, 그 결과는 다음과 같다. 자기 모델링 기법의 처치 효과를 나타내는 처치전과 처치단계의 수업관련부분에서 관찰영역을 제외한 영역의 교수 행동 빈도와 강도 또한 효과적인 것으로 나타났다. 또한, 처치효과의 지속성을 나타내고 있는 처치후의 교수행동 또한 처치 전과 비교하였을 때, 수업관련 부분에서 관찰영역을 제외한 영역에서 다소 높거나 동일한 수준의 빈도와 강도(지속시간)수준을 보였다.

A theme park is a tourism destination attracting a lot of tourists. Many local authorities establish theme parks within their own territory. Busan Metropolitan City tries to host an attractive theme park, and to make the city known as the tourism destination for 21st century. The purpose of this paper is to suggest a policy and management strategy of theme park based on questionnaire analysis for international tourists visiting Busan. First, it is needed to supply low land price to reduce construction cost and to attract investors from the public and private sectors. Second, the theme park has to have attractive themes and new events for repeaters. Third, infra structures related to the theme parks should be provided for the easy accessibility. Finally more emphasis should be placed on public relation and service education for employees.

A new sprouting soybean variety, 'achaekong'was developed at the National Yeongnam Agricultural Experiment Station (NYAES) in 2002. It was selected from the cross Hannamkong/Eunhakong. The preliminary, advanced, and regional yield trials for evaluation an

A new vegetable soybean variety, “Danmiput” was selected from the cross Keunol/Wasehakucho (Introduced), and developed in 2002 on the basis of its yield performance and seed quality for vegetable soybean at the National Yeongnam Agricultural Station. “Dan

A new pea variety, “Dacheong”, was developed at the National Yeongnam Agricultural Experiment Station in 2002. It was selected from the cross Frescoloy/Upton//YP113(Sparkle/Early Bird)/YP115(Sparkle/Euisungjaerae) in 1992. The preliminary, advanced, and r

A new soybean variety, “Daol” was developed at the National Yeongnam Agricultural Experiment Station in 2002. It was selected from the cross Keunol//Josaengbaekjo/Keunol. The preliminary, advanced, and regional yield trials for evaluation and selection of

Sindongjinbyeo is a new japonica rice cultivar developed from a cross between Hwayeongbyeo and YR13604Acp22 line by the rice breeding team of National Honam Agricultural Experiment Station (NHAES), RDA, in 1999. This cultivar has a large grain and about 1

Manpung is a new japonica rice cultivar developed from three-way cross between Nakdongbyeo, Iri390 and Milyang111 by the rice breeding team of National Honam Agricultural Experiment Station (NHAES), RDA in 2000. This cultivar has a short grain shape and a