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        검색결과 450

        201.
        2012.10 구독 인증기관·개인회원 무료
        Many bumblebee species have declined in number in recent decades, particularly in developing regions. Widespread declines of bumblebee species threaten the pollination levels of both wildflowers and crops. Here, we investigated the body weight and colony-developmental characteristics of Korean native bumblebee (B. ignitus) queens collected from 2000 to 2010 for conservation of native bumblebees for breeding. The average weight of 6,852 queens was 0.77 ± 0.44 g. The weight of B. ignitus queens collected in 2005 was the greatest, 0.87 ± 0.12 g, which was 1.0–1.3-fold heavier than any other year. The average oviposition rate was 81.6 ± 10.7%, and 2004 showed the highest rate, 95.0%. This value corresponded to 1.1-1.6-fold increases over the queens collected in the other years. The average rate of colony foundation was 60.9 ± 11.0%. Queens in 2008 exhibited the best performance, 75.4%, which was 1.0-1.9-fold higher than the other years. The rate of progeny-queen production averaged 27.0 ± 9.4% (Fig. 5) and peaked in 2001 at 43.2%; this value was 1.1–4.7-fold higher than other years. The average number of queens produced and number of generations begotten by queens was 27.6 ± 10.1% and 4.8 ± 2.0, respectively. Queens in 2000 averaged 9 generations of offspring, which was 1.1-3.1-fold greater than other years. These results indicate that the colony-developmental characteristics of the collected queens changed significantly between 2000 and 2010. In addition, there was no correlation between body weight and number of queens collected, although body weight was affected by collection year. Since 2008, the colony- developmental characteristics of queens have worsened.
        203.
        2012.06 구독 인증기관·개인회원 무료
        Oct4 and Nanog are transcription factors involved in pluripotency of stem cells. In general, Oct4 is up-regulated by Nanog. In previous results, however, Oct4 was differentially regulated by various doses of Nanog in P19 cells. High dose Nanog down-regulated the Oct4 expression. This negative feedback event was performed by DNMT and HDAC through the inhibitor assays (5-AZA-cytidine and trichostatin A). To identify the precise recruited sites for DNMT and HDAC, ChIP assay was performed in differential doses of Nanog. As a result, HDAC1, HDAC2, DNMT3A and Nanog were recruited to CR2, CR3, CR1, and CR4 upon high dose Nanog, respectively. Next, to investigate the differentiation potency of the cells upon high dose Nanog, RT-PCR with specific markers for three germ layers was performed. However, there was no increase for three germ layers in high dose Nanog treated cells except E-cadherin expression. E-cadherin is a specific marker for epithelial cells. Taken together, high dose Nanog induces Oct4 down-regulation and results in differentiating embryonic carcinoma cells to epithelial cell type. These results will be helpful for study on regulation of pluripotency-related genes in embryonic stem cells. * This study was supported by 2012 Post Doctoral Fellowship Program of National Institute of Animal Science, Rural Development Administration, Republic of Korea. This work received grant support from the Agenda Program (No.PJ007577), Rural Development Administration, Republic of Korea.
        204.
        2012.05 구독 인증기관·개인회원 무료
        We evaluated insecticidal and acetylcholine esterase inhibition activity of 11 Apiaceae plant essential oils and their constituents against male and female adults of Blattella germanica. Of 11 Apiaceae plant essential oils tested, dill (Anethum graveolens), carvi (Carum carvi), and cumin (Cuminum cyminum) essential oils demonstrated > 90 % fumigant toxicity against male adults of German cockroach at 5 mg/filter paper. In contact toxicity test, dill (Anethum graveolens), carvi (Carum carvi), cumin (Cuminum cyminum), and ajowan (Trachyspermum ammi) essential oils produced strong insecticidal activity against male and female adults of German cockroach. Among test compounds, carvone, 1,8-cineole, trans-dihydrocarvone, cuminaldehyde, trans-anethole, p-cymene, and γ-terpinene demonstrated strong fumigant toxicity against male and female adults of B. germanica. In a contact toxicity test, carveol, cuminaldehyde, (S)-(+)-carvone, trans-anethole, thymol, and p-cymene showed the strong contact toxicity against B. germanica male and female adults. IC50 values of α-pinene, carvacrol, and dihydrocarvone against female acetylcholine esterase were 0.28, 0.17, and 0.78 mg/mL, respectively. The toxicity of blends of constituents identified in 4 active oils indicated that carvone, cuminaldehyde, and thymol were major contributors to the fumigant or contact toxicity of the artificial blend.
        205.
        2012.05 구독 인증기관·개인회원 무료
        The larvicidal activity of 12 Apiaceae essential oils and their constituents was evaluated against third instar larvae of mosquitoes, Aedes albopictus. Of the 12 Apiaceae essential oils, Dill (Anethum graveolens), Caraway seed (Carum carvi), Cumin (Cuminum cyminum), Carrot seed (Daucus carota), Parsley (Petroselinum sativum) and Ajowan (Trachyspermum ammi) oils at 0.1 mg/ml exhibited 90% larval mortality after 2 days. Analysis by gas chromatography-mass spectrometry led to identification of 8, 3, 13, 12 compounds, respectively. in the oils of Dill (Anethum graveolens), Caraway seed (Carum carvi), Cumin (Cuminum cyminum), Ajowan (Trachyspermum ammi). The compounds thus identified were tested individually for their larvicidal activities against Aedes albopictus. At this same concentration, the individual constituents tested, α-phellandrene, α-Terpinene, ρ -cymene, (+)-Limonene, γ-Terpinene, Thymol, Carvacrol resulted in 100% mortality after 2 days. At this same concentration, the individual constituents tested, (+)-carvone, cuminaldehyde, neral, trans-anethole resulted in 80% mortality after 2 days.
        206.
        2012.05 구독 인증기관·개인회원 무료
        We evaluated insecticidal activity of 11 Apiaceae plant essential oils and their constituents against rice weevil, Sitophilus oryzae.. Of 11 Apiaceae plant essential oils tested, dill (Anethum graveolens), carvi (Carum carvi), caraway seed (Carum carvi) and cumin (Cuminum cyminum) essential oils demonstrated strong fumigant toxicity against adults of rice weevil. Components of 4 active compounds were analyzed by GC and GC-MS, and fumigant toxicity of individual compound was also tested. Among test compounds, carvone, dihydrocarvone, carveol, linalool oxide, neral, cuminaldehyde, and anethole demonstrated the strong insecticidal activity. The toxicity of blends of constituents identified in 4 active oils indicated that carvone, and cuminaldehyde were major contributors to the fumigant toxicity of the artificial blend.
        207.
        2012.05 구독 인증기관·개인회원 무료
        The pinewood nematode, Bursaphelenchus xylophilus is a serious forest pathogen in many countries including Japan, China and Korea. To minimize the environmental problems caused by synthetic chemicals broadly utilized in the control of B. xylophilus, we estimated the nematicidal potency of 97 phytochemicals (49 monoterpenes, 17 phenylpropenes, 16 sesquterpenes and 15 sulfides) against B. xylophilus by measuring their inhibition activity against acetylcholinesterases (ACE, EC 3.1.1.7) of B. xylophilus (BxACEs). In the primary inhibition assay using B. xylophilus crude protein, (+)-α-pinene, (-)-α-pinene and 3-carene in the monoterpenes, ο-anisaldehyde and coniferyl alcohol in the phenylpropenes and cis-nerolidol in the sesquterpenes were observed the > 50% BxACE inhibition rate and they were subsequently estimated the inhibition rate against three recombinant BxACEs. The (+)-α-pinene and coniferyl alcohol showed the high inhibition rate against BxACE-1 and BxACE-2. Interestingly, coniferyl alcohol also exhibited the high inhibition rate against BxACE-3 which would be insensitive to ACE inhibitors.
        208.
        2012.05 구독 인증기관·개인회원 무료
        Bumblebees are widely used to pollinate various crops, especially tomato, in greenhouses and fields. Here, we investigated whether different sugar solutions have any effects on the oviposition and colony development of Bombus terrestris queens. The types of sugar solution used were a white sugar solution, brown sugar solution, dark brown sugar solution, and prepared sugar solution; all solution contained with a 40% sugar concentration and 0.3% sorbic acid. Among these sugar solutions, B. terrestris queens reared on the white sugar solution exhibited the best results; the rates of oviposition, colony foundation and progeny-queen production were75.0± 11.0, 33.0 ± 9.6 and 21.7 ± 7.3, respectively, which corresponded to 1.1-33.0-fold increases over the results of other sugar solutions. Queens reared on the prepared sugar solution did not found any colonies. The death rate within one month was lowest for the queens reared on the white sugar solution at 26.1 ± 10.9%, which was 1.2–2.0-fold lower than the rate for the other sugar solutions. Furthermore, the numbers of progeny produced by queens reared on the white sugar solution, 131.4 ± 38.8 workers and 51.0 ± 40.6 queens, were also higher, corresponding to 1.1-1.2-fol d increases compared to queens raised on the other sugar solutions. Therefore, the white sugar solution was the favorable sugar solution for the egg-laying and colony developmental characteristics of B. terrestris queens.
        209.
        2011.12 구독 인증기관 무료, 개인회원 유료
        Growth hormone (GH) is obligatory for growth and development. But, there is controversy on the GH effect about reproductive processes of sexual differentiation, pubertal maturation, gonadal steroidogenesis, gametogenesis and ovulation. This study was conducted to investigate the effect of GH on estrus, ovulation and embryo implantation. The results obtained were as follows. GH stimulated to increase estrus rate (p<0.05), pregnancy rate (p<0.05), and total fetus number in mice treated for superovulation. Also, the correlation between GH and steroids, E2 and P4, at peri-estrus stage/ peri-ovulation stage/ peri-implantation stage of the superovulation-induced mice was examined. Consequently, GH co-injected with PMSG especially increased P4 level (p<0.05) at peri-estrus stage of superovulationinduced mice. In conclusion, GH co-treatment in superovulation system boosted the rate of estrus, pregnancy and total fetus by increasing progesterone level at peri-estrus stage of superovulation-induced mice.
        4,000원
        210.
        2011.10 구독 인증기관·개인회원 무료
        Unstable Epigenetic reprogramming was DNA methylation, imprinting, RNA silencing, co-valent modifications of histones and remodelling by other chromatin-associated complexes. After fusion with an enucleated oocyte, a differentiated somatic cell can restructure its genetic program and acquire totipotent characteristics. However, these cases happen only with low frequency. primordial germ cells (PGC) was effectively remove of epigenetic modifications in the genetic totipotency which is necessary for the development. The present study was in vitro development of reconstruct PGC NT embryos compared with somatic cell NT embryos. The rate of cleavage did not differ between NT embryos from PGC and somatic cells (87.26 vs 91.36%). However, the rate of development to the blastocyst stage was significantly higher in PGC cell NT than somatic cell NT (31.03 vs 19.27%). PGC from a slightly younger stage of development have succeed to promote normal development of recipient eggs. This difference in results between germ cell and somatic cell nuclear transfers could only be a reflection of intimate differences in their reprograming. These results suggest that PGC NT embryos are significantly higher for the in vitro development. Furthermore, These study may represent an approach towards achieving better production of transgenic animal.
        211.
        2011.10 구독 인증기관·개인회원 무료
        In DNA barcoding, the DNA degradation of old museum specimens has been limited full-length (658bp) sequencing. The challenges associated with the retrieval and authentication of degraded DNA extracts from fossil and old museum specimens were principally limited to analyze the relatively short sequences (<300 bp). Furthermore, almost protocols in other to analyzed the degraded DNA contained the cloning process after PCR causing the time-consuming and the rising costs. To overcome these problematic circumstances, we tried a modified method to analyze full-length of DNA barcoding region in 30~60 year-old butterfly specimens (225 samples in 28 species), using direct sequencing after PCR with species-specific overlapping primer sets per each species. As a result, all of 28 species have been successfully analyzed, although 178 samples (79%) are completely generated barcoding sequences ranged from 640 to 658 bp and 47 samples (21%) are partially sequenced ranged from 100 to 500 bp. Thus, the result showed that the direct PCR sequencing using the overlapping primer sets per species appears to have great potential efficiency for analysis of degraded DNA without incorrect sequences.
        212.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The phenethyl ester of caffeic acid (CAPE), an active component of honeybee propolis extract, is shown to inhibit cancer growth previously. However, studies on human ovarian cancer are largely obscure. This study evaluated the effects of CAPE as a potenti
        4,000원
        214.
        2010.10 구독 인증기관·개인회원 무료
        We investigated nesting and foraging behavior of Korean mason bees, Osmia cornifrons Radoszkowski, during apple orchard pollination. When O. cornifrons was nesting, the oviposit and store pollens were taken an average 118.54±15.88 second and constructing cell partition was an average 109.33±62.09 second. At foraging, collecting pollens was timed at an average 699.89±81.87 second, and carrying mud was measured an average 464.88±151.17 second. Nesting and foraging behavior of O. cornifrons were influenced by weather conditions, especially, temperature, luminance and wind. When the luminance was more than 20,000lux and temperature was more than 20℃, O. cornifrons was more actively nesting and foraging. But, nesting and foraging of O. cornifrons were rapidly dropped when the wind blew at the speed more than 5m/s. The correlation analysis showed that foraging behavior is weak positive correlation with luminance, temperature and nesting. On the other hand, there is negative correlation between wind and the behavior of O. cornifrons. The most effective factor was luminance among the factors affecting the weather condition by regression analysis. Therefore, if weather conditions is low luminance, low temperature and strong wind, it will be better not to use O. cornifrons during apple pollination.
        215.
        2010.10 구독 인증기관·개인회원 무료
        Bumblebees are widely used to pollinate various crops, especially tomato, in greenhouses and fields. An artificial hibernation is essential for year-round rearing of the bumblebee that undergoes one generation per year. Here, we investigated whether a cold temperature and humidity affect artificial hibernation of the bumblebee queen Bombus terrestris. In cold temperature regimes of 0℃, 2.5℃, 5℃, 7.5℃ or 12.5℃ under a constant humidity 70% over, the queens stored at 2.5℃ was the best performance in survival rate, which was 74.0% in one month, 67.0% in two months, 60.0% in three months, 46.0% in 4 months, 33.0% in 5 months, and 24.0% in 6 months and lowed in the order of 0℃, 5℃, 7.5℃ and 12.5℃. And also, the colony developmental characteristics after diapause was 1.2-1.5 fold higher than those at queens stored at 5℃. In terms of cold humidity, the queens hibernated at 70% under 2.5℃ was the best performance in survival rate, which was 93.3±3.4% in one month, 83.3±0.0% in two months, 76.7±0.0% in 3 months and 36.7±12.1% in 5 months and lowed in the order of 50% and 90%. The rates of oviposition, colony foundation and progeny-queen production of queens hibernated at 70% were 80.8%, 30.8% and 30.8%, respectively. These values correspond to 1.7-3.3 fold that at queens stored at 50%. Therefore, 2.5℃ and 70% R.H. were the favorable cold temperature and humidity conditions for diapauses-break of B. terrestirs queen.
        216.
        2010.10 구독 인증기관·개인회원 무료
        Cambodia covers an area of 181,035 sq km, among them, forests cover 53 percent, so there are abundant Insect diversities. Collecting expeditions of Insect were conducted several times from 2009 to 2010 (09. 7.2-7.11, 10.16-22, 12.25-12.30, 10. 4. 30-5.6) in Cambodia sponsored by Natioanl Biological Resources, Korea. Central Cadamon Protected Forest (N 11 41' 13" E 103 26' 31.3"), Seima Biodiversity Conservation Area (N 12° 08' 20.8", E 106 55' 2.7") and Prov. Pursat, Roveang (N 12° 19' 06.5", E 103° 3' 03.8") were main area surveyed by pitfall trap, light trap and sweeping, searching etc. Numerous individuals were collected and more than 150 species belonging to 40 families were founded, among them, there were lots of new and new recorded species. Among Cambodian insects, species of Lepidoptera, Coleoptra and Hymenoptera were preferentially introduced in here. The photos for species of dominant, rare, new and new recorded were provided, and also collecting sites and activities were presented.
        217.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We prepared the amine epoxy adducts (AEA)/thin multiwalled carbon nanotubes (TWCNTs) composite particles using nonsolvent based methods including dry mechano-chemical bonding(MCB) process and supercritical fluid (SCF) process. The resulting TWCNTs/AEA composite particles have been used as curing agents for urethane modified bispheol A type epoxy resin. The thermal, thermomechanical properties of the epoxy resins cured with TWCNTs/AEA composite particles were measured by DMA and the dispersion of CNT was characterized by SEM. Because of high degree of CNT dispersion, thermal and mechanical properties of the epoxy resin cured with TWCNTs/AEA composite particles prepared by SCF process are better than those cured with mechano-chemically prepared TWCNTs/AEA composite particles.
        4,000원
        218.
        2010.05 구독 인증기관·개인회원 무료
        Cambodia covers an area of 181,035 sq km among them, forests cover 53 percent. As a tropical monsoon climate, average annual rainfall is about 1,400 mm(about 55 in) on the central plain and increases to as much as 3,800 mm (150 in) in the mountains and along the coast. The average annual temperature is about 27°C (about 80°F). There are many wildlife diversity in Cambodia, but regulated or unregulated logging and mining have diminished the country's wildlife rapidly. This expedition was conducted three times in 2009 (7.2-7.11, 10.16-22, 12.25-12.30). Central Cadamon Protected Forest (N 11° 41' 13" E 103° 26' 31.3") and Seima Biodiversity Conservation Area (N 12° 08' 20.8", E 106° 55' 2.7") were main area surveyed by pitfall trap, light trap and sweeping etc. As the result, totally 611 individuals of 11 families in Coleoptera was collected, among them Gonocephalumspecies of Tenebrionidae was highest number and species in Melonthidae, Chrysomelidae and Dynastidae etc., were collected, specially kind of Hydrophilidae species from wetland was surved in the expedition.