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        검색결과 437

        163.
        2016.10 구독 인증기관·개인회원 무료
        For useful research animal to study human’s disease and for xenotransplantation donor, pig was studied to improve the quality of in vitro production (IVP). But, still the developmental ability of in vitro porcine embryos is still lower than in vivo embryos. Using a antioxidant is one of the strategy to overcome the drawback of in vitro producted embryos by protecting the oocyte from free radicals during in vitro maturation (IVM). Resveratrol, one of the plant-derived polyphenol antioxidants, have been used as effective antioxidants. Therefore, resveratrol treatment during IVM of porcine oocytes is expected to improve efficiency of the IVP by reducing free radical accumulation. In this study, we designed control (no treated) and resveratrol treatment groups (0, 2 and 4uM), evaluated maturation rate, cleavage rate, blastocyst formation rate and total cell number. Additionally GSH and ROS accumulation levels were measured via staining oocytes. In the results, maturation rate had not shown significant difference among the groups. However, in further development, not only the results of cleavage rate (0uM : 84.64±2.65 vs 4uM : 93.67±2.36, p<0.05) and blastocyst formation rate (0uM : 6.39± 0.90, vs 4uM : 13.67±2.32, P<0.05) were significantly increased in 4uM resveratrol treated group, and result of total cell number (0uM : 22.47±0.76 vs 2, 4uM : 30.35±1.76, 27.65±1.23, P<0.05) also shown significant difference in 2, 4uM resveratrol groups with control. GSH accumulated levels of matured oocytes in resvetrol treated groups were significantly higher than control. Meanwhile ROS levels of treated groups were significantly reduced [GSH (0uM : 142±10.49 vs 2, 4uM : 163.2±3.29, 169.7±0.94, P<0.05), ROS (0uM : 170.2±7.76 vs 2, 4uM : 118.6±7.90, 130±7.07, P<0.05)]. From these results, we conclude the treatment of resveratol improved further development of porcine embryos by regulating intracellular GSH, ROS levels during porcine IVM. Therefore, exogenous antioxidants such as a resveratol can be supportive substances for obtaining the improved quality of IVP.
        165.
        2016.10 구독 인증기관·개인회원 무료
        Euzophera batangensis (Lepidotera: Pyralidae) is seriously damaging trunks or branches of persimmon tree (Diospyros sp.). We tested the attractiveness of (Z)-9-tetradecen-1-ol (Z9-14OH) and (Z9,E12)-tetradeca- 9,12-dien-1-ol (Z9,E12-14OH) with single or blended baits at southern parts of Korea in 2014 and 2015. The monoene was not attractive at all at three places during the two years. In 2014, diene was equally or more attractive than the mixture in Jinju and Suncheon, respectively. In 2015 too, the attractiveness of diene and mixture was not different in Jinju and Munsan. Monitoring of the seasonal occurrence of E. batangesis with the sex pheromone components revealed that it occurred three times a year; the first occurrence from early April to mid May, the second from early Jun to mid July, and the third from late August to late September.
        166.
        2016.10 구독 인증기관·개인회원 무료
        We evaluated the larvicidal activity of 12 Apiaceae plant essential oils and their components against the Asian tiger mosquito, Aedes albopictus, and the inhibition of acetylcholine esterase with their components. Of the 12 plant essential oils tested, ajowan (Trachyspermum ammi), caraway seed (Carum carvi), carrot seed (Daucus carota), celery (Apium graveolens), cumin (Cuminum cyminum), dill (Anethum graveolens), and parsley (Petroselinum sativum) resulted in >90% larval mortality when used at 0.1 mg/mL. Of the compounds identified, α-phellandrene, α-terpinene, p-cymene, (-)-limonene, (+)-limonene, γ-terpinene, cuminaldehyde, neral, (S)-+-carvone, trans-anethole, thymol, carvacrol, myristicin, apiol, and carotol resulted in >80% larval mortality when used at 0.1 mg/mL.
        167.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As a replacement for activated carbon, biochar was synthesized and used for the adsorptive removal of formaldehyde and nitrogen oxide. Biochar was produced from the fast pyrolysis of the red marine macro alga, Pyropia tenera. The P. tenera char was then activated with steam, ammonia and KOH to alter its characteristics. The adsorption of formaldehyde, which is one of the main indoor air pollutants, onto the seaweed char was performed using 1-ppm formaldehyde and the char was activated using a range of methods. The char activated with both the KOH and ammonia treatments showed the highest adsorptive removal efficiency, followed by KOH-treated char, ammonia-treated char, steam-treated char, and non-activated char. The removal of 1000-ppm NO over untreated char, KOH-treated char, and activated carbon was also tested. While the untreated char exhibited little activity, the KOH-treated char removed 80% of the NO at 50°C, which was an even higher NO removal efficiency than that achieved by activated carbon.
        4,000원
        168.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cyanotoxins in aquatic ecosystems have been investigated by many researchers worldwide. Cyanotoxins can be classified according to toxicity as neurotoxins (anatoxin-a, anatoxin-a(s), saxitoxins) or hepatotoxins (microcystins, nodularin, cylindrospermopsin). Microcystins are generally present within cyanobacterial cells and are released by damage to the cell membrane. Cyanotoxins have been reported to cause adverse effects and to accumulate in aquatic organisms in lakes, rivers and oceans. Possible pathways of microcystins in Lake Suwa, Japan, have been investigated from five perspectives: production, adsorption, physiochemical decomposition, bioaccumulation and biodegradation. In this study, temporal variability in microcystins in Lake Suwa were investigated over 25 years (1991~2015). In nature, microcystins are removed by biodegradation of microorganisms and/or feeding of predators. However, during water treatment, the use of copper sulfate to remove algal cells causes extraction of a mess of microcystins. Cyanotoxins are removed by physical, chemical and biological methods, and the reduction of nutrients inflow is a basic method to prevent cyanobacterial bloom formation. However, this method is not effective for eutrophic lakes because nutrients are already present. The presence of a cyanotoxins can be a potential threat and therefore must be considered during water treatment. A complete understanding of the mechanism of cyanotoxins degradation in the ecosystem requires more intensive study, including a quantitative enumeration of cyanotoxin degrading microbes. This should be done in conjunction with an investigation of the microbial ecological mechanism of cyanobacteria degradation.
        4,500원
        169.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Refuse-derived fuel (RDF) produced using municipal solid waste was pyrolyzed to produce RDF char. For the first time, the RDF char was used to remove aqueous copper, a representative heavy metal water pollutant. Activation of the RDF char using steam and KOH treatments was performed to change the specific surface area, pore volume, and the metal cation quantity of the char. N2 sorption, Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), and Fourier transform infrared spectroscopy were used to characterize the char. The optimum pH for copper removal was shown to be 5.5, and the steam-treated char displayed the best copper removal capability. Ion exchange between copper ions and alkali/alkaline metal cations was the most important mechanism of copper removal by RDF char, followed by adsorption on functional groups existing on the char surface. The copper adsorption behavior was represented well by a pseudo-second-order kinetics model and the Langmuir isotherm. The maximum copper removal capacity was determined to be 38.17 mg/g, which is larger than those of other low-cost char adsorbents reported previously.
        4,000원
        171.
        2016.04 구독 인증기관·개인회원 무료
        The purpose of this stduy was to identify accurately and promptly the Microsporidia disease of bumble bees from Gangwon in Korea. Bumble bees are crucial pollinators of various crops and microsporidia are the critical infections of these hosts. Also, the various species of bumble bees have been used: Bombus terrestris, B. lucorum, B. occidentalis, B. ignites and B. impatiens etc. The symptoms of bumble bees infected microsporidia: their abdomens become distended, paralyzed and become sluggish and die early. We have identified the morphologies of the microsporidium by electron microscopy and found that the morphology of the microsporidium is rounded spore morph, with fairly small spores as described before in many other articles. For the specific and sensitive diagnosis of Nosema in bumble bees, we have developed the improved method of Polymerase Chain Reaction (PCR) conditions for expeditious diagnosis. Two pairs of primers were tested on N. bombi and the related microsporidia; Nosema apis and Nosema sp., both of which infect bumble bees and honey bees and further we have verified and analyzed DNA sequence data of N. bombi in bumble bees by using the BLAST server at the National Center for Biotechnology Information.
        172.
        2016.04 구독 인증기관·개인회원 무료
        Seagrasses, sea flowering plants, comprise approximately 60 species globally and are often called ‘ecosystem engineers’ because they create their own habitats by modifying the surrounding environments, which provide coastal zones with a number of crucial ecosystem services. Zostera marina (the common name ‘eelgrass’) is one of the seagrass beds-forming species distributed widely in northern hemisphere including the Korean coast, which plays a pivotal role in ecosystem as a primary producer and a nursery habitat or refuge for other marine organisms. However, due to global climate change and anthropogenic activities such as reclamation and dredging, there has recently been a drastic decline in population sizes of Z. marina in Korea. In order to develop effective conservation and restoration management programs of Z. marina populations, it would be helpful to consider all biological aspects of this species such as genetic characteristics as well as ecological and physiological features. This study first provides information on genetic diversity and genetic structure of Jeju Island and Namhae populations of Z. marina, which will contribute to the establishment of appropriate conservation and restoration management plans for future persistence of this species. Using six microsatellite markers, we investigated the level of genetic diversity and genetic structure among 10 geographic populations of Z. marina inhabiting Jeju Island (Hamdeok, Tokki-seom, Sungsan, Woljeong, Ojo) and Namhae (Gamak bay, Jindong bay, Nampo, Anggang bay, Geoje) on the southern coast of Korea. The level of genetic diversity within Jeju populations (mean allelic richness [AR]: 1.57 ~ 3.09) was found to be significantly lower than Namhae populations (AR: 3.09 ~ 4.29) (Mann-Whitney U-test, P < 0.05). These findings suggest that effective population sizes (Ne) of Jeju populations are generally smaller than those of Namehae populations. Within Jeju Island, Hamdeok population had the smallest population size (coverage: 138 m2) and the lowest genetic diversity (AR: 1.57), while Ojo population had the largest population size (coverage: 275,736 m2) and the greatest level of genetic diversity (AR: 3.09). Hamdeok population showed evidence of genetic bottleneck. These results again suggest that Ne of Jeju populations is generally low (except Ojo population). Among Jeju populations, all pair-wise comparisons of FST values (i.e., degree of genetic differentiation) were highly significant (FST = 0.0612 ~ 0.7168, P < 0.001) despite Jeju populations that were geographically closely located, indicating that these local populations are genetically divergent, probably due to a lack of gene flow among the populations. The observed strong population structure was substantiated by evidence that five genetic clusters are most likely, based on population assignment test (STRUCTURE). The Mantel test showed a positive relationship between genetic distance (FST) and geographic distance (km) across all the populations sampled (R2 = 0.4118, P < 0.05), suggesting that our data follow Isolation By Distance (IBD) model. Woljeong population revealed the highest level of FST values compared to other populations within Jeju Island in IBD. STRUCTURE and factorial correspondence analysis (FCA) further showed that some Woljeong individuals included genotypes of Namhae populations. Population size of Woljeong (coverage: 310m2) was approximately 50 % smaller than that of Sungsan (coverage: 841m2); however, extent of its genetic diversity (AR: 2.39) was even higher than that of Sungsan population (AR: 1.77). We speculated that Woljeong population underwent a transplantation from Namhae populations with relatively higher level of genetic diversity. FST values within Namhae populations were relatively lower (compared to within Jeju Island) despite the populations that were geographically more distant. It means that level of gene flow is higher among Namhae populations than among Jeju populations. Z. marina is known to have different life histories by water depth. In subtidal zone (deep water depth) populations predominantly undertake sexual reproduction through seeds such as annual life history, whereas those of intertidal zone (shallow water depth) undertake both sexual and asexual reproductions through horizontal rhizomes i.e., perennial life history. STRUCTURE analysis showed no clear differences between shallow and deep populations at Namhae, but some FST values were statistically significantly different despite their low values. For Geoje population sampled in 2005, intertidal and subtidal populations were not significantly different (FST = 0.0045, P = 0.033), but these populations sampled in 2015 showed a significant difference (FST = 0.0328, P < 0.001). It means that genetic structure of Geoje has been changed over the 10 year period between shallow and deep populations. Overall, the Jeju and Namehae populations analyzed in the current study have relatively low levels of genetic diversity and distinct genetic compositions, which warns the message that this ecologically important species should be conserved separately in the local populations and with high priority. We propose that future conservation and restoration plans for seagrasses should consider genetic characteristics particularly because a close relationship between genetic diversity and ecological performance in marine species has been well documented.
        178.
        2015.10 구독 인증기관·개인회원 무료
        Trehalose is a major blood sugar in insects. It functions as carbohydrate nutrient source to all tissues with a relatively constant level and also serves as a cryoprotectant at high levels in some insects. Thus, its hemolymph levels need to be controlled according to physiological conditions. An insulin-like peptide, SeILP1, was identified and showed to mediate down-regulation of the hemolymph trehalose levels of Spodoptera exigua larvae. This study showed that hemolymph trehalose levels of S. exigua significantly increased upon immune-challenge and under starvation in a time-dependent manner. During up-regulation of the hemolymph trehalose, the gene expression of trehalose phosphate synthase significantly increased, but that of trehalase significantly decreased. Injection of biogenic monoamines, such as octopamine and serotonin, did not increase the hemolymph trehalose levels. Either treatment of arachidonic acid or eicosanoid biosynthesis inhibitor did not change the hemolymph trehalose levels. However, injection of adipokinetic hormone (AKH) of Manduca sexta significantly increased the trehalose levels. Interrogation of Spodobase identified an AKH-like gene of S. exigua. Its expression increased with starvation in the larvae. Its RNA interference significantly prevented the up-regulation of the hemolymph trehalose levels in S. exigua.
        179.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted from October 2014 to May 2015 to explore forage production and feed values of Italian ryegrass, Rye and whole crop barley as winter forage crops in the Southern region of Korea. The experimental location was over 10 points for each species and each sampling point area was 1 m² (Width: 1 m × Length: 1 m). Air mean temperature and rainfall in the Southern region of Korea during the experimental period was 6.95 ± 5.75℃ and 70.45 ± 54.68 mm, respectively. Fresh forage yield of Italian ryegrass, the most cultivated forage in the Southern region of Korea, was 44.4 ± 7.0 ton/ha. The percentage of dry matter for whole crop barley was 28.9 ± 7.0%. Crude protein (CP) was higher in Italian ryegrass (10.7 ± 5.3%) while total digestible nutrient (TDN) had the highest value in whole crop barley. Crude protein was not significantly different by location. However, the neutral detergent fiber (NDF), acid detergent fiber (ADF) and total digestible nutrient value of forage from Jeonbuk province were higher than in forage from Gyeongnam province.
        4,000원
        180.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Korean National Residue Program (KNRP) use three plans for the sampling of domestic meats: monitoring, surveillance, and exploratory testing. We analyzed the results of monitoring and surveillance for residual veterinary drugs and pesticides in meat during 2012 and 2013. KNRP targets food-producing animals including cattle, pigs, chickens, ducks, sheep (goats), and horses. Sampling mainly focuses on veterinary drugs and pesticide residues found in tissues such as muscle, kidney, and liver. A total of 548 residue violations occurred between 2012 and 2013, mainly in pigs (427 violations) and cattle (113 violations). The most commonly found compounds were antimicrobials such as penicillins, fluoroquinolones, aminoglycosides, tetracyclines, sulfonamides, and macrolides. Pig residue violations were mainly for the presence of penicillins (34%) and fluoroquinolones (28%), while most residue violations in cattle were due to the presence of penicillins (32%) and aminoglycosides (27%). The overall rates of violations were 0.21% in 2012 and 0.10% in 2013. A major cause of violations was the failure to follow the appropriate withdrawal periods (68.8%). The results of the KNRP were analyzed to provide information on agricultural chemical residues that are of public health concern and to help control and prevent residue violations for ensuring food safety.
        4,000원