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        검색결과 23

        1.
        2024.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Sestrin 2 (SESN2) is a member of the sestrin family of stress-induced proteins that negatively regulate agingassociated biological processes. This study aims to investigate the role of SESN2 in regulating the differentiation potential and senescence of mesenchymal stem cells (MSCs) derived from young and elderly donors. Bulk RNA sequencing revealed a common decline in the SESN2 mRNA levels in MSCs from elderly individuals, which was confirmed via reverse transcription-polymerase chain reaction and western blot analyses. SESN2 knockdown in MSCs from young donors resulted in phenotypic changes similar to those in MSCs from elderly donors, including an enhanced expression of senescence and adipogenic markers and diminished expression of osteogenic markers. To confirm the effect of decreased SESN2 expression on osteogenic and adipogenic differentiation, we induced Sesn2 knockdown in mouse bone marrow-derived MSCs. Sesn2 knockdown suppressed the mRNA expression of osteogenic marker genes, alkaline phosphatase activity, and matrix mineralization. Furthermore, Sesn2 knockdown enhanced mRNA expression of the adipogenic marker genes and intracellular lipid accumulation. These results suggest that a decline in SESN2 expression during aging contributes to the shift of MSC differentiation from osteogenic to adipogenic lineage.
        4,000원
        2.
        2023.10 구독 인증기관·개인회원 무료
        The onion thrips, Thrips tabaci, is a serious global pest attacking many agricultural crops such as onion and Welsh onion. The thrips, assumed to originate in the Mediterranean region, has been reported for a long time in South Korea. According to worldwide molecular works, the species composes of three genetic lineages (LI, L2 and T) which related to reproductive mode (arrhenotoky vs. thelotoky). To understand the genetic diversity of T. tabaci in South Korea, we investigated genetic lineage and haplotype composition, using about 80 mitochondrial COI gene sequences (369bp) along with foreign sequences from GenBank and BOLD. The COI gene analysis shows that both of thelotokous L1 and arrhenotokous L2 population distribute in South Korea. Among 97 COI-haplotypes worldwide, only six haplotypes are found and thelotokous H1 dominantly distributes.
        4.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined the document Shaemirok, which recorded the daily lives of people from Jangsoo (長水), Junrado to Pyeongang (平康), Gangwondo, from 1591 to 1601. This book represents the mid Josun dynasty Noble Lineage's diary together with Muk-Jae (默齋日記). This study analyzed the Shaemirok of Noble lineage’s seasonal food and traditional Korean food through the lens of the Shaemirok. The Shaemirok recorded that Josun people practiced the Julsa (節祀) and Julshik (節食) during the spring, as follows: Sakil (中和節) five times on February 1, Dapchungil (Samjiknal) six times on March 3, Hanshikil five times on March 8, and Deungsuk (Chopile) three times on April 8. Samjiknal on March 3, which is mentioned six times, is the spring Julsa and Julshik that show up most frequently within the Shaemirok’s records. The Shaemirok recorded that Josun people, practiced the Julsa and Julshik during the summer, as follows: Danyang (Danoh) eight times on May 5 Youdoojul six times on June 15, Chilsuk five times on July 7, and Bakjoong five times on July 15. Dangohjul on May 5, which is mentioned eight times, is the summer Julsa and Julshik that show up most frequently within the Shaemirok’s records. The Shaemirok’s author recorded Julsa and Julshik practiced in the autumn eight times annually. Joongangjul, which is mentioned six times, is the autumn Julsa and Julshik that show up most frequently within the Shaemirok’s records. Shaemirok recorded that Josun people practiced the Julsa and Julshik during the winter, as follows: Dongji during November, Sul on January 1, and Daebohrum on January 15 Dongji and Sul, Daebohrum are mentioned eight and seven times, respectively, in the Shaemirok. The people of the Four Main Families of the mid-period Josun practiced more Julsa and Julshik in the winter than in any other season. The Josun people stored the most food during winter, thus had the highest abundance of food. This seasonal factor explains Dongji and Sul, Daebohrum’s unusual frequency with which they were celebrated.
        4,600원
        5.
        2017.10 구독 인증기관·개인회원 무료
        The migratory locust, Locusta migratoria, is one of the famous insect pests in the world. Although the species revealsseveral morphological variations, it is largely divided into two lineages, Southern (Africa, Southern Europe, Southern Asia,and Australian) and Northern (East Asia, Eurasian continent). In 2014, a large number of L. migratoria nymphs withred-brown color were suddenly occurred in the southern region (Haenam-gun, Jeollanam-do) of Korea. In this study, mitochondrialCOI sequences were analyzed to recognize the genetic identity of L. migratoria with nymph or adult samples collectedfrom 15 localities in Korea. The analysis results reveal that most of all samples are belonging to the Nothern lineage,and the Southern lineage was discovered only in Iksan and Chunju of Korea.
        6.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Coffee (Coffea spp.) is one of the most important agricultural commodities, being widely consumed in the world. Various beneficial health effects of coffee have been extensively investigated, but data on habitual coffee consumption and its bio-physiological effect have not been clearly explained as well as it is not proved the cause and effect between drinking coffee and its bio-physiological reactions. We made the dialyzed coffee extract (DCE), which is absorbable through gastrointestinal tract, in order to elucidate the cellular effect of whole small coffee molecules. RAW 264.7 cells, a murine macrophage lineage, were directly treated with DCE, i.e., DCE-2.5 (equivalent to 2.5 cups of coffee a day), DCE-5, and DCE-10, for 12 hours, and their protein extracts were examined by immunoprecipitation high performance liquid chromatography (IP-HPLC). RAW 264.7 cells differently expressed the inflammation-related proteins depending on the doses of DCE. RAW 264.7 cells treated with DCE showed marked increase of cathepsin C, cathepsin G, CD20, CD28, CD31, CD68, indicating the activation of innate immunity. Particularly, the macrophage biomarkers, cathepsin G, cathepsin C, CD31, and CD68 were markedly increased after DCE-5 and DCE-10 treatments, and the lymphocyte biomarkers, CD20 and CD28 were consistently increased and became marked after DCE-10 treatment. On the other hand, RAW 264.7 cells treated with DCE showed consistent increase of IL-10, an anti-inflammatory factor, but gradual decreases of different pro-inflammatory proteins including TNFα, COX-2, lysozyme, MMP-2, and MMP-3. In particular, the cellular signaling of inflammation was gradually mitigated by the reduction of TNFα, COX-2, IL-12, and M-CSF, and also the matrix inflammatory reaction was reduced by marked deceases of MMP-2, MMP-3, and lysozyme. These anti-inflammatory expressions were consistently found until DCE-10 treatment. Therefore, it is presumed that DCE may have dynamic effects of innate immunity activation and pro-inflammation suppression on RAW264.7 cells simultaneously. These effects were consistently found in the highest dose of coffee, DCE-10 (equivalent to 10 cups of coffee a day in man), that might imply the small coffee molecules were accumulated in RAW 264.7 cells after DCE-10 treatment and produce synergistic cytokine effects for innate immunity activation and anti-inflammatory reaction concurrently.
        4,000원
        8.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, among the domestic MMORPG narrative research is scarce, it began to study to determine the trend. In order to identify trends, selected for study, Big company ‘NCsoft’ has made 「Lineage」, 「Aion」, and「Blade & Soul」. Glassner the selection of works based on the Branching Narrative structure is proposed and analyzed the structure of the narrative of the three games. Analysis of each game is found to be fused in the form of branch narrative structure. And fusion forms from the past to the present was to get the results came increasingly been reduced. If the results of this study will be a springboard to the MMORPG narrative analysis and impact studies conducted in the future.
        4,000원
        9.
        2015.04 구독 인증기관·개인회원 무료
        Psyllids are a serious pests of pears cultivated in temperate and subtropical regions. Pear psyllids are a member of the large genus Cacopsylla (Psyllidae: Psyllinae). Among the 28 psyllid species that infect pear trees, Cacopsylla chinensis (Yang and Li, 1981) is considered the most harmful. Recently, we found new pear psyllid pest affected Korean pear (Pyrus pyrifolia var. culta) orchards. The psyllid is morphologically identical to C. chinensis and is herein reported as a new record. In this study, we conducted DNA sequence analysis of the mitochondrial cytochrome oxidase I-leucine tRNA-cytochrome oxidase II (COI-tRNALeu-COII) and 16S rDNA regions to demonstrate the phylogenetic relationships among C. chinensis from pear orchards in Korea, and those recorded from China, Taiwan and Japan. The sequence of the COI-tRNALeu-COII and 16s rDNA regions were equivalent from Korea. Comparison of nucleotide sequences and phylogenetic analysis differentiated Korean psyllids from the Chinese and Taiwanese C. chinensis, but Korean and Japanese psyllids were closely related. The results suggest that Korean and Japanese C. chinensis are genetically homologous. It is presumable that these individuals descended from a single colony that was probably introduced recently.
        10.
        2013.12 구독 인증기관 무료, 개인회원 유료
        To clarify the role of stem cells in hepatocarcinogenesis, CD44 expression was investigated in mouse livers as well as embryonic cell lineages treated with diethylnitrosamine (DEN). Liver tumors induced by DEN were analyzed by immunohistochemisty for CD44. Liver tissues were sampled at 6, 24, and 48 hr after treatment with saline or DEN. Mouse embryonic stem cells (ESCs), hepatic progenitor cells (HPCs), and hepatocyte like cells (HCs), representing 0, 22, and 40 days of differentiation, respectively, were treated with DEN at four doses (0, 1, 5, and 15 mM, respectively) for 24 hr, after which CD44 expression levels were examined by relative quantitative real-time PCR. CD44 expression was weakly detected in tumor cells as well as in some hepatocytes surrounding the tumor cells. However, CD44 expression was not detected in liver tissue treated with DEN at early time points. The CD44 mRNA expression level was significantly different among cells treated with 5 mM DEN at day 22 (P<0.01) as well as 1, 5, and 15 mM DEN at day 40 (P<0.01) compared with control. Taken together, CD44 expression slightly increased in mouse DEN-induced tumors. Furthermore, expression of CD44 in embryonic cell lineages treated with various doses of DEN significantly differed among embryo stem cells and derived hepatic lineage cells. This suggests that CD44 expression may be modulated in the progeny of stem cells during their differentiation toward hepatocytes, and its expression may increase in the tumor stage but not during early carcinogenesis.
        4,000원
        11.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Rabies is a zoonotic disease that causes severe destruction to the central nerve system which is usually fatal. It is one of the most important disease around the world and particular in Asia because of the high costs of prevention and post-exposure treatment. After the recurrence of sylvatic rabies in 1993, the number of raccoon dog mediating rabies cases in Korea has maintained annually until 2011. To better understand the current rabies epidemics in Korea, Korean rabies isolate (SKRBV0601GY) from Gyeonggi province in 2006 was compared with previous isolates in Korea and with isolates originating from the North-East Asia, such as Japan, China and Russia, based on complete nucleoprotein (N) gene sequences. By comparison of the N genes among these viruses, SKRBV0601GY revealed that nucleotide similarity ranged from 97.7 to 99.7%, 96.4 to 97.5%, 91.4 to 96.3%, 89.2 to 90% and 86.1 to 88.1% with Korean isolates, "Arctic-like-2" viruses, "Arctic" viruses, Russian group C - E and Chinese isolates, respectively. Phylogenetic analyses of the isolates revealed that the Korean isolate in 2006 belonged to Korean group B. The topology of the phylogenetic tree of Korean isolates related not the species and year of isolation but the geological location of the virus isolates. All of the Korean isolates showed close relationship to the "Arctic-like-2" virus (Russian group B) more than the "Arctic" virus (Russian group A) and all of the Chinese isolates (Chinese group A, B and C). The "Arctic-like-2" virus group contains the Japanese isolate and Russian group B viruses, originating from the south of East Siberia and Far East in Russia. These molecular data demonstrated that the current rabies epizootic in Korea developed independently of Chinese groups and originated from the "arctic-like-2" viruses in detail.
        4,000원
        12.
        2011.03 구독 인증기관 무료, 개인회원 유료
        Two piglets and one juvenile pig were used to investigate closely what types of cells express green fluorescent protein (GFP) and if any, whether the GFP-tagged cells could be used for stem cell transplantation research as a middle-sized animal model in bone marrow cells of recloned GFP pigs. Bone marrow cells were recovered from the tibia, and further analyzed with various cell lineage markers to determine which cell lineage is concurrently expressing visible GFP in each individual animal. In the three animals, visible GFP were observed only in proportions of the plated cells immediately after collection, showing 41, 2 and 91% of bone marrow cells in clones #1, 2 and 3, respectively. The intensity of the visible GFP expression was variable even in an individual clone depending on cell sizes and types. The overall intensities of GFP expression were also different among the individual clones from very weak, weak to strong. Upon culture for 14 days in vitro (14DIV), some cell types showed intensive GFP expression throughout the cells; in particular, in cytoskeletons and the nucleus, on the other hand. Others are shown to be diffused GFP expression patterns only in the cytoplasm. Finally, characterization of stem cell lineage markers was carried out only in the clone #3 who showed intensive GFP expression. SSEA-1, SSEA-3, CD34, nestin and GFAP were expressed in proportions of the GFP expressing cells, but not all of them, suggesting that GFP expression occur in various cell lineages. These results indicate that targeted insertion of GFP gene should be pursued as in mouse approach to be useful for stem cell research. Furthermore, cell- or tissue-specific promoter should also be used if GFP pig is going to be meaningful for a model for stem cell transplantation.
        4,000원
        13.
        2010.09 구독 인증기관 무료, 개인회원 유료
        Embryoid bodies (EBs) generated from human embryonic stem cells (hESCs) include spontaneously induced endodermal lineage cells (ELCs). Activin-A plays important roles in the endoderm differentiation of hESCs. Despite studies on the generation of ELCs from hESCs with treatment of Actvin-A, it was unclear for localization and pattern of ELCs by Activin-A during differentiation of hESCs. Accordingly in this study, we knew that Actvin-A increased the cystic EBs formation, including the highly enriched AFP (endoderm lineage specific marker)-expressing cells in the surface of cystic EBs. To induce the EBs formation from undifferentiated hESCs, cells were transferred onto petri-dish and cultured in suspension condition without bFGF removed hESC media (EB media) for 3 days. Next to investigate the effect of Activin-A, EBs were subsequently cultured in EB media supplement with 100 ng/ml Activin-A for 3 days. After 5~7 days of Activin-A treatment, cystic EBs began to appear which increased in numbers reaching ~60% of initially formed EBs over 5 days. Endoderm lineage marker, AFP were highly expressed and specifically localized at the surface region of cystic EBs comparison with normal EBs. We next attached the cystic EBs onto gelatin-coated plates and cultured for 5 days. In the results of real-time PCR and immunocytochemistry analysis, AFP-expressing cells migrated and localized at the outgrowth region of attached cystic EBs. To obtain the AFP-expressing cells of the outgrowth region, we manually isolated by using micro- dissection and cultured them. These cells strongly express AFP over 70% of isolated cells post re-plating. Here, we first showed an expression pattern of specifically localized ELCs by Activin-A during differentiation of hESCs. From this observation, we could highly purified ELCs from undifferentiated hESCs. Taken together, our system will provide a novel and efficient option to generate ELCs from hESCs.
        4,000원
        14.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        온라인 게임은 불특정다수의 유저가 가상세계라는 공간에 모여 새롭게 구축해낸 또 하나의 사회공동체이다. 사회가 원활하게 유지되기 위해서는 구성원들 간의 조화를 이루기 위한 내부 규율이 필요하다. 그렇다면 온라인 게임에서의 내부 규율은 무엇일까? 온라인 게임은 게임 제작사의 의도한 바에 따라 창조된 가상세계이다. 그러나 유저들에 의해 그 세계는 변형되고 재창조된다. 이에 따라 온라인 게임의 내부 규율을 형평성에 입각하여 게임과 유저, 유저와 유저간의 조화를 살펴보고자 한다.
        4,000원
        16.
        2005.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The central aim of this thesis is to see if the structure of Palsangjeon(捌相殿) in Pubjoo Temple(法住寺), a five sto wooden pagoda in Chosen(朝鮮) Dynasty, was handed down from the ancient and middle ages. This study was performed through an analysis of Gilt-Bronze Pagoda built in Koryo(高麗) period. In other words, it is aimed at analyzing which lineage the structure of Palsangjeonbelongs to as a wooden pagoda. In analyzing the structure of Palsangjeon, I attempted to find out its source from the remains of Koryo period prior to the Chosen Dynasty. Examples are the Gilt-Bronze Pagoda, built during the Koryo period. I have also examined its relationship with other existing wooden pagodas and remains. The analysis of Palsangjeon, a five story wooden pagoda in Chosen Dynasty, focuses on the following: First, I explored the possibilities of whether the structure of Palsangjeon was newly invented in Chosen Dynasty, or if it had been derived from the wooden pagodas in the Koryo period. Secondly, I tried to find out if the stable vertical planes, with a great successive diminution ratio, were derived from the middle age, i.e. Koryo period. The results of the study of Palsangjeon through Gilt-Bronze Pagoda analysis are as follows: 1. The structure of Gilt-Bronze Pagoda, a wooden pagoda from the Koryo period, is roughly classified into the accumulation type, using pipe pillars, and the one story type using whole pillars. In the accumulation type, stories are connected in either a flat format or an intervening format. The Gilt-Bronze Pagoda is mainly composed of pipe pillars, with some whole pillars. However, the central pillar was omitted in the building structure. Generally, the upper and lower stories are connected by pipe pillars in a crutch format. All the pillars, whether they are pipe pillars or whole pillars, used Naiten(內轉) technology. The Eave supporter has the Haang type(下昻) and the Muhaang type(無下昻). In most cases, high balustrades are furnished, but few tables of high balustrades have been found. The slanting roof formats have been handed down from Paekche(百濟), Silla(新羅), or Koryo(高麗). However, the structure of the octagon is assumed to be derived from Koguryo(高句麗). The structure of the Gilt-Bronze Pagoda from the Koryo period is mainly composed of accumulated flat squares, with some spire types. intervening format, the structure of Palsangjeon used whole pillars in a half story format in which upper level side pillars are installed on the lower level tie beam. From the Bronze Pagoda from the Koryo period, we can assume that the half story format of wooden pagodas that has stable vertical planes with a great successive diminution ratio was created during the mid-Koryo period at the latest and had been idly developed by the time of the Chosen Dynasty. 3. The whole pillars in Palsangjeon are also found in Gilt-Bronze Pagodas from the Koryo period. Hence, all of the pillars in Palsangjeon seem to have been handed down from the ancient construction technology. They were also used in the construction of wooden pagodas from the Koryo period. Therefore, it is assumed that Palsangjeon was constructed using the construction technology of the Chosen Dynasty that had been developed from the wooden pagoda construction technology of the Koryo period. The stable vertical planes with a great successive diminution ratio in Palsangjeon are derived from ancient Korean wooden pagodas, which have developed into indigenous Korean wooden pagodas with fairly stable vertical planes and a great design, in the half story format of Koryo and Chosen Dynasty. Therefore, it is assumed that the structure of Palsangjeon has a systematic relationship with traditional Korean wooden pagodas and is one of the indigenous Korean wooden pagoda structures. 4. In China, the intervening format has been mainly used between stories in multi-story architecture since the ancient days. At the same time, the flat format as also used in ancient and middle ages. However, the flat format was replaced by whole pillars during the Ming(明) and Manchu(淸) Dynasties, in favor of simple and compact construction. The half-story format, in which upper level side pillars are installed on tie beams, has been found in some cases, but it doesn't seem to have been the primary construction technology. Few traces of the half-story format have been found in multi-story architecture in Japan, and it has not been used as a general construction format. By contrast, the half-story format, which seems to have been derived from the Koryo period, was used as a general construction format in multi-story architecture of the Chosen Dynasty. The construction technology of multi-story architecture is related to that of multi-story wooden pagodas, but they have different production technologies. It seems that the structure of Palsangjeon did not just adopt the construction technology of multi-story architecture in the Chosen Dynasty, but it was developed from wooden pagodas in the Koryo period, including the Gilt-Bronze Pagoda. 5. Since the ancient days, most Chinese and Japanese wooden pagodas have adopted an accumulation type of structure using pipe pillars, with accumulated pointed towers. On the other hand, though most Korean wooden pagodas have also adopted an accumulation type of structure from the ancientdays, one story type using whole pillars was created in the Koryo and Chosen Dynasties. The wooden pagoda structure of Palsangjeon, with stable vertical planes in a half story format, is a unique Korean construction technology, different from the construction technologies of Chinese and Japanese wooden pagodas. This thesis clearly determined the structural characteristics of Palsangjeon. However, various remains have yet to be analyzed in depth, to establish an accurate construction technology system. In the beginning of this thesis, I had difficulty in precisely interpreting the internal structure of the Gilt-Bronze Pagoda from its appearance. However, in the process of study, the more serious problem was that there are few remains or ruins of multi-story architecture in ancient and the middle ages of Korea. Therefore, it is urgent to discover various remains in the future. This thesis succeeded in determining the structural characteristics of Palsangjeon. However, it fell short of clarifying the structural lineage of the stable vertical planes, although they show indigenous Korean architectural taste, representing the unique national emotion, and the construction format of multi-story wooden pagodas in Korea. I hope this is clarified in the future research.
        5,100원
        18.
        2018.06 KCI 등재 서비스 종료(열람 제한)
        본 논문은 모바일 RPG게임 내 인앱 결제 서비스 이용자들에 대한 사용성 평가를 통해 향후 국내 모바일 RPG게임 개발자 및 기획자들에게 업데이트 및 개발에 필요한 자료를 모색하고 제안하는 데 그 목적을 두었다. 모바일 게임 '리니지M'의 인 앱 결제 서비스를 주로 이용하는 이용자들을 대상으로 정량적 평가를 위한 사용성 평가를 실시했다. 사용성 평가를 위한 도구로는 피터모빌(Peter Morville)이 정의한 'The User Experience Honeycomb'를 기준으로 설계한 설문지를 통해 설문조사를 하였다. 이러한 통계결과를 접근성, 가치성, 신뢰성, 매력성, 사용성 총 5가지 측면으로 나누어 분석하였고, 이를 통하여 새로운 모바일 RPG게임 개발에 도움을 줄 것으로 기대한다.
        19.
        2018.05 서비스 종료(열람 제한)
        Backgoound : Various varieties of Schisandra chinensis (Omija) are grown in various regions of Korea. However, there is no study on varieties with excellent efficacy for each variety. Therefore, in this study, it is aimed to select the excellent lineage by analyzing the active compounds of Omija collection species Methods and Results : 154 lineage of Omija was collected from Muju of Jeollabuk-do, Jangsu of Jeollabuk-do and Hoengseong of Gangwon-do. They were cultivated in test-research farm in Rural Development Administration at Eumseong of Chungcheongbuk-do and used as materials. In order to analyze the active compounds (Shizandrin A, Shizandrin C, Gomisin A, Gomisin N) in Omija, the HPLC method described in the Korean Pharmacopoeia (compounds of Omija indicator) was used. As a result of analysis of functional compounds, SC-003, SC-005, SC-013, SC-015, SC-019, SC-020, SC-022, SC-023, SC-040, SC-042, SC-045, SC-066, SC-069 and SC-072 were collected from Jangsu, Jeollabuk-do, SC-082 was collected from Hoengseong, Gangwon-do and SC-139 was collected from Muju, Jeollabuk-do showed higher contents of functional compounds than other collected species. Conclusion : As demand for high income crop has increased, new cultivar breeding is required to produce high quality Schisandra chinensis (Omija). In this study, Shisandra A, Shizandrin C, Gomisin A and Gomisin N were analyzed as functional compounds of Omija. They can be used for new Omija breeding. Especially SC-003, SC-019, SC-022, SC-040, SC-045, SC-069 and SC-082 can be superior lineags with high functional compound contents.
        20.
        2015.09 서비스 종료(열람 제한)
        In animal development, the mechanisms by which localized factors and organelles in egg cytoplasm were exactly distributed into each daughter cell are essential for formation of various cell types. During ascidian Halocynthia roretzi embryogenesis, ooplasmic mitochondria were mainly segregated into muscle and neural precursor cells. At the 32-cell stage, localized mitochondria in the B6.2 blastomeres were preferentially distributed into the B7.4 muscle precursors compared with the B7.3 mesenchyme/ notochord precursors. When the B6.2 blastomeres were isolated from the early 32-cell stage embryos and then allowed to divide 2 times of cell division, the resultant partial embryos showed symmetric distribution of mitochondria, and the partial embryos were composed of equal size cells. In normal development, cell fates of the B7.3 blastomere were correlated with the unequal cleavage of B6.2 lineage cells that normally occurs in the next two-cell division stages to produce a large B8.5 mesenchyme and a small B8.6 notochord cell. Mitochondria are distributed asymmetrically in both cells. When embryos were treated with FGF receptor inhibitor SU5402 and MEK inhibitor U0126 between the 32-cell and the early 64-cell stages, the resultant embryos showed equal cleavage pattern and symmetric distribution of mitochondria in daughter cells of the B6.2 blastomeres. However, blocking of Nodal and Notch signaling did not affect the cell division pattern and mitochondrial distribution in the B6.2 lineage blastomeres between the 32-cell and 110-cell stages. Therefore, it is likely that FGF/MEK signaling is involved in asymmetric distribution of mitochondria and unequal cleavage of the B6.2 lineage blastomeres in ascidian embryo.
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