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        검색결과 69

        65.
        2010.09 서비스 종료(열람 제한)
        Autophagy is an evolutionarily conserved lysosomal pathway for degrading cytoplasmic proteins, macromolecules, and organelles, in addition to recycling protein and ATP synthesis. Although programmed cell death (PCD) is very important during embryogenesis, the mechanism underlying the dynamic development during this process remains largely unknown. In order to obtain insights into autophagy and it's relation with apoptosis in early embryo development, we first evaluated LC3 gene expression levels in mouse embryos developing in vitro. qRT-PCR revealed high expression levels from 1- to 4 cell stage embryo, and then expression decreased during morula and blastocyst formation. Indirect immunocytochemistry showed protein synthesis of LC3 in these stage embryos. Introducing of autophagy inhibitor, 3-MA (2mM) significantly decreased both developmental rate (54.85±11.0%) and total cell number (n=71±8), but increased apoptosis rate (5.68± 1.9%) at the blastocyst. Real time RT-PCR confirmed reduced expression of selected autophagy related genes, including ULK1, Atg4A, B, C, D, Atg5, Atg8, Gabarap, Atg9A, B and Atg16L. Treatment of autophagy inducer, rapamycin (50 ng/㎖) increased both mRNA expression and protein synthesis of LC3 and apoptosis rate (16.11±3.42%), but decreased developmental rates (50.16±9.78) and total cell numbers (n=60±7) as compared to control developmental rate (70.74±12.9%), Total cell number (89.8±9) and apoptotic cell death (1.11±0.7%). These results suggest that autophagy is related with apoptosis in mouse embryo, which possibly give a role for early development.
        66.
        2010.09 서비스 종료(열람 제한)
        Mitochondria are important regulators of both apoptosis and autophagy. One of the triggers for mitochondrial-mediated apoptosis is the production of reactive oxygen species (ROS), which include hydrogen peroxide, superoxide, hydroxyl radical, nitric oxide, and peroxynitrite. Recently, several studies have indicated that ROS may also be involved in the induction of autophagy. In the present study, we used H2O2 to induce mitochondrial stress and examined apoptotic- and autophagic-related gene expression and observed LC3 protein (autophagosome presence marker) expression in porcine parthenotes developing in vitro. In porcine four-cell parthenotes cultured for 5 days in NCSU37 medium containing 0.4% BSA, the developmental rate and mitochondrial distribution did not differ from that of the group supplemented with 100 μM H2O2 but significantly decreased in the group supplemented with 500 μM H2O2 (P<0.05). Transmission electron microscopy (TEM) indicated that whereas normal shaped mitochondria were observed in blastocysts from the control group, abnormal mitochondria (mitophagy) and autophagic vacuoles were observed in blastocysts from the group that received 500 μM H2O2. Furthermore, addition of H2O2 (100 μM and 500 μM) decreased cell numbers (P<0.05) and increased both apoptosis (P<0.05) and LC3 protein expression in the blastocysts. Real time RT-PCR showed that H2O2 significantly decreased mRNA expression of anti-apoptotic gene Bcl-xL but increased pro-apoptotic genes, Caspase 3 (Casp3) and Bak, and autophagy-related genes, microtubule-associated protein 1 light chain 3 (Map1lc3b) and lysosomal-associated membrane protein 2 (Lamp2). However, the addition of H2O2 had no effect on mRNA expression levels in nuclear DNA-encoded mitochondrial-related genes, cytochrome oxidase (Cox) 5a, Cox5b, and Cox6b1, but decreased mitochondrial DNA-encoded genes, D-loop (Dloop) and cytochrome b (Cytb), in blastocysts. These results suggest that H2O2 leads to mitochondrial dysfunction that results in apoptosis and autophagy, which is possibly related to porcine early embryo development.
        67.
        2010.09 서비스 종료(열람 제한)
        Spc25 is a component of the Ndc80 complex which consists of Ndc80, Nuf2, Spc24, and Spc25. Previous work has shown that Spc25 is involved in regulation of kinetochore microtubule attachment, localization of Ndc80, and the spindle assembly checkpoint in mitosis. The role of Spc25 in meiosis remains unknown. Here, we report its expression, localization and functions in mouse oocyte meiosis. The Spc25 mRNA level gradually increased from the GV to MI stage, but decreased by MII during mouse oocyte meiotic maturation. Immunofluorescent staining showed that Spc25 was restricted to the germinal vesicle, and associated with chromosomes during all stages after GVBD. Overexpression of Spc25 resulted in oocyte meiotic arrest, chromosome misalignment and spindle disruption. Conversely, Spc25 RNAi resulted in precocious polar body extrusion and caused severe chromosome misalignment and aberrant spindle formation. Spc25 RNAi affected Ndc80 localization, but Ndc80 RNAi did not affect Spc25 localization.Survivin MO caused Ndc80 dispersion but did not affect localization of Spc25. Our data suggest that Spc25 is required for chromosome alignment, spindle formation, and spindle checkpoint activity through the regulation of Ndc80, but that Spc25 function is independent of survivin during meiosis.
        68.
        2004.05 KCI 등재 서비스 종료(열람 제한)
        The experiment was conducted to evaluate the effects of medicinal plants on ethanol-metabolism. Sprague Dawley rats divided into 6 groups (n=8), fed with 10% ethanol and diets supplemented with each 1% of four plant extracts, α-tocopherol (as positive control) and fiber (as negative control) for 4 weeks. Group supplemented with plant extract of Ulmus davidiana showed the most high value (322 nM NADH/min/mg protein) in alcohol dehydrogenase (ADH) activity among the experimented groups (144~312 nM NADH/min/mg protein) at p〈0.05. Groups fed with Lagerstroemia indica and Zelkova serrata extract-supplemented diets indicated high activity in aldehyde dehydrogenase (ALDH, 16.7 & 12.3 M NADH/min/mg protein), which were comparatively lower than 20.1 M NADH/min/mg protein of α-tocopherol fed group. All of the groups fed with plant extracts indicated very low GPT activities (13.9~17.3 IU/l) compared to those (146.1 & 128.6 IU/l) fed with α-tocopherol and fiber at p〈0.05. From these results, it is suggested that Lagerstroemia indica have a potent ethanol-metabolizing activity.
        69.
        2004.05 KCI 등재 서비스 종료(열람 제한)
        Four medicinal plants selected from preliminary screening study were evaluated in the aspects of their antioxidant activities in alcohol-intoxicated rats. Rats fed 1% α-tocopherol-supplemented diet as positive control and ones done α-tocopherol-deficient diet as negative control were compared with ones done the plant extract-supplemented diet (n=8). After the administration of the experimental diets for 4 weeks, typical increments in activities of manganese-superoxide dismutase (Mn-SOD) and glutathione peroxidase (GSH-px) indicated in alcohol-intoxicated rats, were not observed in ones fed Lagerstroemia and Ulmus extract-supplemented diet. The content of thiobarbituric acid reactive substance (TBARS), the product of lipid peroxidation, did not increased in rats fed plant extracts-supplemented diet except for Terminalia. From the results, it is concluded that Lagerstroemia and Ulmus have physiologically efficient antioxidant activities.
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