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        검색결과 60

        21.
        2018.11 구독 인증기관·개인회원 무료
        U0126 is a highly selective inhibitor of both MEK1 and MEK2, a type of MAPK/ERK kinase. This study was conducted to evaluate the effect of U0126 treatment during in vitro maturation (IVM) on nuclear maturation, intra-oocyte glutathione content, and embryonic development after parthenogenesis (PA). U0126 (5 μM) was supplemented to IVM medium during the first 0 (control), 2, and 4 h. The basic medium used for IVM was medium-199 supplemented with 10% (v/v) porcine follicular fluid (standard), 0.6 mM cysteine, 0.91 mM pyruvate, 75 μg/ml kanamycin, and 1 μg/ml insulin. Immature pig oocytes were matured for 44 h and then oocytes reached metaphase II stage were electrically activated to induce PA. The in vitro culture medium for embryonic development was porcine zygote medium-3 containing 0.3% (w/v) fatty acid-free BSA. When immature oocytes were treated with U0126 during the first 0, 2, 4 h of IVM culture, nuclear maturation was significantly (P < 0.05) increased by the U0126 treatment for 4 h (96.2 ± 1.3%) compared to standard IVM (90.6 ± 2.1%). Cleavage of PA embryos was significantly increased by 4 h- treatment (90.6 ± 2.2%) compared to standard medium (83.9 ± 1.8%). In addition, blastocyst formation of PA embryos was significantly (P < 0.05) increased by the treatment for 4 h (55.8 ± 5.7%) compared to 2 h (38.1 ± 6.1%). The glutathione contents in IVM oocytes were not altered by the U0126 treatments for 0, 2, and 4 h (1.28 ± 0.10, 1.16 ± 0.09, and 1.10 ± 0.09, respectively). Our results demonstrated that 5 μM U0126 treatment during the first 4 h of IVM showed positive effects on nuclear maturation, cleavage, and embryonic development in pigs.
        22.
        2018.11 구독 인증기관·개인회원 무료
        Poor embryo quality and low blastocyst formation have been major limitations in establishment of cloned embryonic stem cells and production of cloned animals through somatic cell nuclear transfer (SCNT). Aggregation of embryos is a promising method for improving developmental competence of blastocysts. The aim of this study was to improve the blastocyst formation and the quality of parthenogenetic (PA) pig embryos by the aggregation of blastomeres at the 4-cell stage that were cultured in various type of culture dishes with or without phytohemagglutinin (PHA). The PA embryos were produced by the general method of our laboratory. On Day 2 after PA, the zona pellucida of 4 cell-stage embryos were removed by treatment with 0.5% (wt/vol) pronase solution. The 3x zona-free blastomere (ZFB) were randomly distributed in each of the following treatments for aggregation. ZFB were cultured for 5 days at 39℃ in an atmosphere 5% CO2, 5% O2, and 90% N2. In Experiment 1, effect of culture dishes on the aggregation efficiency and developmental competence of PA embryos were investigated. ZFB were cultured on non-coated (control) culture dish or dishes coated with 1% (wt/vol) agarose substrate (AS) or Well of the Well in dishes coated with 1% (wt/vol) agarose substrate (WAS). The ZFB cultured in WAS showed significantly higher (P<0.05) aggregation (81.2%) than AS and control (21.6-45.5%). The mean cell number in blastocysts derived from AS and WAS (81.4-89.3 cells/blastocyst) was significantly higher (P<0.05) than that of control (63.8 cells/blastocyst). In Experiment 2, effects of 150 ug/ml PHA treatment on the aggregation efficiency and developmental competence of embryos were investigated. The ZFB cultured in AS with PHA showed a higher (P<0.05) aggregation rate (90.0%) than that in AS without PHA, control with PHA, and control (39.2%, 57.9% and 17.5%, respectively). In conclusion, aggregation of porcine ZFB treated with PHA and agarose substrate could be a useful technique for producing improving blastocyst development with increased mean cell number of blastocysts in pigs.
        23.
        2018.10 구독 인증기관·개인회원 무료
        This study was conducted to evaluate the time required to sell Protaetia brevitarsis larvae when larvae fed on three kinds of fermented berries sawdust, such as mulberry, raspberry, and blueberry. The first instar larvae were reared in a plastic container(543x363x188mm) with designated feeds, and investigated the cumulative proportion of larvae more than 2.5g at rearing room regulated at 25±1℃ with 50~60% under 16:8(L:D). When we reared larvae for about 45 days with fermented blueberry sawdust, the cumulative proportion of larvae with more than 2.5g was over 70%. It was about 40 days shorter than fermented oak sawdust. For each group, the average survival rates of larvae at the possible time for sale were 72~93%.
        24.
        2018.10 구독 인증기관·개인회원 무료
        The hypopharyngeal gland (HPG) of the honeybee worker produces royal jelly (RJ) and has a developmental cycle closely related to the division of labor. In this study, we investigated to compare the HPG acini diameter of differently aged worker bees with high royal jelly producing colony (HRC) or less producing colony (LRC). Additionally, we also evaluated whether the fresh weight of the head is a reliable indicator of the developmental status of HPG. The HRC showed a significantly higher RJ production about two-times as compared with those of the LRC. We measured the HG-diameters on days 1, 3, 6, 9, 12, 15. The microscopic analysis revealed that the acini size of the HRC was significantly larger than the LRC. In addition, the acini diameter of HRC was 15% longer than the LRC on the first day after emerging. It was shown that the fastest development during 3 days which is preparing for nurse the brood. The HPG acini diameters increased in both colonies in a similar fashion until day 12 and then decreased. We also compared the fresh head weight of the experimental colonies, differences were similar to the development of HPG. Therefore, high royal jelly production may have a positive correlation between HPG acini size and the fresh head weight.
        25.
        2018.04 구독 인증기관·개인회원 무료
        This study was conducted to evaluate the the efficacy of mulberry cake mixed diet on larval growth of Protaetia brevitarsis. As a result of adding 3, 5, and 10% mulberry cake to the fermented mulberry sawdust, the development period of the Protaetia brevitarsis larvae was 44.9days, 44.6days, and 41.8days, and the highest weight of larvae was 2.76g, 2.80g, and 2.89g, respectively. As a result of adding 3, 5, and 10% mulberry cake to the fermented oak sawdust, the development period of the Protaetia brevitarsis larvae was 46.7days, 41.6days, and 41.7days, and the highest weight of larvae was 2.65g, 2.65g, and 2.56g, respectively.
        26.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Porcine spermatogonial stem cells (SSCs) prefer three-dimensional (3D) culture systems to 2D ones for the maintenance of self-renewal. Of the many 3D culture systems, agar-based hydrogels are candidates for supporting porcine SSC self-renewal, and there are various types of agar powder that can be used. In this study, we sought to identify an agar-based 3D hydrogel system that exhibited strong efficacy in the maintenance of porcine SSC self-renewal. First, 3D hydrogels with different mechanics were prepared with various concentrations of Bacto agar, lysogeny broth (LB) agar, and agarose powder, and the 3D hydrogel with the strongest alkaline phosphatase (AP) activity and greatest increase in colony size was identified for the different types of agar powder. Second, among the porcine SSCs cultured in the different 3D hydrogels, we analyzed the colony formation, morphology, and size; AP activity; and transcription and translation of porcine SSC-related genes, and these were compared to determine the optimal 3D hydrogel system for the maintenance of porcine SSC self-renewal. We found that 0.6% (w/v) Bacto agar-, 1% (w/v) LB agar-, and 0.2% (w/v) agarose-based 3D hydrogels showed the strongest maintenance of AP activity and the most pronounced increase in colony size in the culture of porcine SSCs. Moreover, among these hydrogels, the strongest transcription and translation of porcine SSC-related genes and largest colony size were detected in porcine SSCs cultured in the 0.2% (w/v) agarose-based 3D hydrogel, whereas there were no significant differences in colony formation and morphology. These results demonstrate that the 0.2% (w/v) agarose-based 3D hydrogel can be effectively used for the maintenance of porcine SSC self-renewal.
        4,000원
        27.
        2017.07 구독 인증기관·개인회원 무료
        Today, consumers are becoming more sensitive to price since price have been an essential motivation for them to choose the electronic retail venue. Recently, it is recognized that social commerce, with higher rate of daily active users, is ahead of traditional electronic mobile commerce in Korea. One of strengths in social commerce is attractive price deals for fashion brands, which positively lead to purchase probabilities. Therefore, fashion retailers should understand consumers’ price perception and their responses toward sales promotions on the social commerce. The purpose of this study is to examine the effect of consumer price perception and choice heuristics on impulse buying behavior for sales promotion of fashion brands and to examine the moderating effect of an engagement level in the social commerce. A self-administered questionnaire was developed, and mainly included consumer price perception (e.g., price consciousness, sales proneness), choice heuristics (e.g., affect referral, price referral), engagement, impulse buying and demographics. An online survey was undertaken by a research agency. A total of 235 usable responses were obtained from Korean consumers who had purchased fashion brands from social commerce sites (e.g., Coupang, Wemakeprice, Ticketmonster, etc.) using mobile devices. Respondents represent more females (n=129, 54.9%) than males (n=106, 45.1%). They are aged from 19 to 39 years old (Means=29). Results showed that consumers’ sales proneness had a positive effect on affect referral and price referral heuristics, which positively lead to impulse buying behavior. However, consumer price consciousness had a negative effect on impulse buying at the social commerce sites. Also, the mediating effect of the engagement was significant in the relationship among sales proneness, choice heuristics, and impulse buying behavior for sales promotion of fashion brands in the social commerce sites. This study discussed marketing implications for social commerce to effectively manage promotional program in the social commerce market.
        28.
        2017.06 구독 인증기관 무료, 개인회원 유료
        Selecting an appropriate antigen with optimal immunogenicity and physicochemical properties is a pivotal factor to develop a protein based subunit vaccine. Despite rapid progress in modern molecular cloning and recombinant protein technology, there remains a huge challenge for purifying and using protein antigens rich in hydrophobic domains, such as membrane associated proteins. To overcome current limitations using hydrophobic proteins as vaccine antigens, we adopted in silico analyses which included bioinformatic prediction and sequence-based protein 3D structure modeling, to develop a novel periodontitis subunit vaccine against the outer membrane protein FomA of Fusobacterium nucleatum. To generate an optimal antigen candidate, we predicted hydrophilicity and B cell epitope parameter by querying to web-based databases, and designed a truncated FomA (tFomA) candidate with better solubility and preserved B cell epitopes. The truncated recombinant protein was engineered to expose epitopes on the surface through simulating amino acid sequence-based 3D folding in aqueous environment. The recombinant tFomA was further expressed and purified, and its immunological properties were evaluated. In the mice intranasal vaccination study, tFomA significantly induced antigen-specific IgG and sIgA responses in both systemic and oral-mucosal compartments, respectively. Our results testify that intelligent in silico designing of antigens provide amenable vaccine epitopes from hard-to-manufacture hydrophobic domain rich microbial antigens.
        4,000원
        35.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to illustrate a general collaborative model of team-teaching in a university general English program. While positive effects of team-teaching and some suggestions for teamteaching practices have been reported previously, there has been less attention paid to an instructional model where native teachers and Korean teachers collaborate with each other for the best classroom experience for students. A qualitative research guided the design. Twenty teachers’ team-teaching classes were observed and video-taped for analysis. The findings showed that the two teachers’ constant negotiations of meanings in any stage of the lessons and in classes with diverse linguistic goals was helpful to the students’ understanding. Also, in the stage of presenting particular language expressions (duringlesson), complimenting each other with native teachers’ intuition and Korean teachers’ analytic skills was suggested as an important instructional move. When activities were introduced, modeling by the two teachers and bridging roles by the Korean teachers were a tremendous contribution and recommended for model collaborations. An instructional model and educational implications have been suggested.
        6,600원
        36.
        2014.10 구독 인증기관·개인회원 무료
        The oedemerid species Oedemera sexualis Marseul, 1877 is reported for the first time from Korea. The genus Oedemera Olivier, 1789, within subfamily Oedemerinae and family Oedemeridae, is one of the common oedemerid beetles being widely distributed throughout the world. The world-widespread genus Oedemera is presented 3 subgenera and 104 species in Palaearctic region. Until now, 8 species and subspecies were recorded in Korea. O. sexualis was found in Is. Yongcho and Is. Bijin in Tongyeong-si, Gyeongsangnamdo of Korea, bringing the number of Korean Oedemera species to 9 species. In this study, we report the taxonomic key to the genus Oedemera of Korea, and morphological description of O. sexualis.
        37.
        2014.06 구독 인증기관 무료, 개인회원 유료
        Despite many researches related with in-vitro culture of porcine spematogonial stem cells (SSCs), adherent culture system widely used has shown a limitation in the maintenance of porcine SSC self-renewal. Therefore, in order to overcome this obstacle, suspension culture, which is known to have numerous advantage over adherent culture, was applied to the culture of porcine SSCs. Porcine SSCs retrieved from neonatal testes were suspension-cultured for 5 days or 20 days, and characteristics of suspension-cultured porcine SSCs including proliferation, alkaline phosphatase (AP) activity, and self-renewal-specific gene expression were investigated and compared with those of adherent-cul-tured porcine SSCs. As the results, the suspension-cultured porcine SSCs showed entirely non-proliferative and significantly higher rate of AP-positive cells and expression of self-renewal-specific genes than the adherent-cultured porcine SSCs. In addition, long-term culture of porcine SSCs in suspension condition induced significant decrease in the yield of AP staining-positive cells on post-day 10 of culture. These results showed that suspension culture was inappropriate to culture porcine SSCs, because the culture of porcine SSCs in suspension condition didn’t stimulate proliferation and maintain AP activity of porcine SSCs, regardless of culture periods.
        4,000원
        38.
        2014.04 구독 인증기관·개인회원 무료
        Nitidulid beetles of the genus Aethina Erichson, 1843 are a well-known group as harmful to agricultural and apicultural industry, especially including A. tumida, an American small hive beetle, which is a beekeeping pest. The world-widespread genus Aethina, within subfamily Nitidulinae and family Nitidulidae, is presented 5 subgenera and 28 species in Palaearctic region. Until now, 2 subgenera, Aethina s. str. and Aethina (Circopes), and 3 species, A. (A.) flavicollis, A. (A.) inconspicua and A. (C.) suturallis, have been recorded in Korea, and we added one more species, A. (A.) maculicollis as a newly recorded species. The larvae of A. (A.) maculicollis have been reported as pests of mulberry fruits in Japan. In this study, we report the taxonomic key to the genus Aethina of Korea, and morphological description of A. (A.) maculicollis.
        39.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to determine the growth performance and carcass characteristics of fattening Hanwoo heifers slaughtered at different ages. Twenty one Hanwoo heifers were randomly allocated to three groups (32, 36 and 40 months age), with 7 steers each, respectively. In the result, initial and final body weights were 125.6 and 651.0 kg, respectively. Average daily gain was significantly low at final stage compared with other growth stages (p<0.05). Dry matter intake was the peak at the intermediate fattening stage (p<0.05). The feed conversion ratio was significantly lower at growing stage compared to other stages (p<0.05). In yield traits, carcass weight was greater in 40 months age group compared to other groups (p<0.05). Yield index was greater in 32 months group compared to 40 months of age (p<0.05). Marbling score, meat color, fat color, texture, and maturity were not different among groups (p>0.05). However, marbling score tended to be increased in 40 months age group (5.9) compared to other groups. The appearance rate (%) of meat quality grade more than 1+ was greater at 40 months old group than other groups.
        4,000원
        40.
        2013.04 구독 인증기관·개인회원 무료
        Olibrus Erichson, 1845 and Olibrus particeps Mulsant & Rey, 1861 (Coleoptera: Cucujoidea: Phalacridae) are reported from Korea for the first time and historical review of the taxonomic position of this genus is provided. The genus Olibrus Erichson is one of the common phalacrid beetles being widely distributed throughout the world. This genus is easily distinguished from other phalacrid genera by combination of the following characters: Antennae inserted at sides of front, base visible from above; Last segment of antenna softly indented; Basal metatarsomere shorter than second; Elytral surface very polished. O. particeps was found in Andong-si and Yeongju-si, Gyeongsangbuk-do of Korea, bringing the number of species within the Korean Phalacridae to 2 species. In this study, we provide a redescription of O. particeps Mulsant & Rey, and illustrations of its genitals and other appendages.
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