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        검색결과 223

        101.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 azoxymethane (AOM)과 dextran sodium sulfate (DSS)로 유도된 대장 발암과정에 대한 셀레늄의 방어 효과를 조사하였다. 셀레늄 결핍(0.02 ppm Se), 정상(0.1 ppm Se), 과다(0.5 ppm Se)사료를 12주간 식이로 급여하여 혈액검사와 대장암 발생의 초기단계인 aberrant crypt foci (ACF)수를 측정했으며, 암 발생율을 조사하였다. ICP-AES 를 사용하여 간의 셀레늄 농도를 측정하였으며, 또한 셀레늄포함 항산화효소인 glutathione peroxidase (GPx) 활성을 알아보았다. 또한 TUNEL assay와 PCNA, β-catenin에 대한 면역조직 염색을 수행하였다. ACF 수 및 종양 발생률에 있어서, 셀레늄과다사료를 급여한 군이 정상셀레늄사료를 급여한 군보다 낮았으며, 셀레늄결핍사료를 급여한 군은 오히려 ACF 수 및 종양 발생률이 높았다. GPx 활성은 셀레늄의 섭취가 과다한 군에서 높게 나타났으며, 이 때, TUNEL 에서 apoptotic positive cell이 증가하는 것을 확인했다. 또 한 셀레늄의 섭취가 과다한 군에서 PCNA와 β-catenin의 발현이 감소됨을 볼 수 있었다. 본 마우스 모델실험에서 셀레늄은 여러 기전에 의해 대장암 발생을 억제할 수 있을 것으로 사료된다.
        4,000원
        102.
        2010.06 KCI 등재 구독 인증기관·개인회원 무료
        Methanol and hot water extracts of Daedalea bien-nis were investigated for its antioxidant activity, poly- phenol content and tyrosinase inhibitory effect. The antioxidant activity was evaluated using 1, 1-diphenyl -2-picrylhydrazyl (DPPH) scavenging assay. The antioxidant activities of hot water and 80% methanol extracts of Daedalea biennis fruiting body were 52.06%. and 92.62% at 1.5mg/ml concentration. Total polyphenol content of hot water and 80% methanol extracts were 12.26㎍ GAEs/mg and 13.69㎍ GAEs/mg. Tyrosinase inhibitory activity of water extract was 19.70% while 80% methanol extract was 15.75% at 1mg/ml concentration.
        103.
        2010.06 KCI 등재 구독 인증기관·개인회원 무료
        Methanol and hot water extracts of Suillus granulatus were investigated for its antioxidant activity, polyphenol content and tyrosinase inhibitory effect. The antioxidant activity was evaluated using 1, 1- dipheny l-2-picrylhydrazyl (DPPH) scavenging assay. The antioxidant activities of hot water and 80% methanol extracts of Suillus granulatus fruiting body were 51.49%. and 90.58% at 1.5mg/ml concentration. Total polyphenol content of hot water and 80% methanol extracts were 33.21㎍ GAEs/mg and 27.97㎍ GAEs/mg. Tyrosinase inhibitory activity of water extract was 7.8% while 80% methanol extract was 20.88% at 1mg/ml concentration.
        104.
        2010.05 구독 인증기관·개인회원 무료
        The toxicity of methanol extract from 28 plants toward four agricultural insect pests were examined using contact toxicity bioassay with spray methods. At a concentration of 1,000 ppm Achyranthes japonica whole body was observed strong activity against Myzus persicae. Paeonia lactiflora root and Corydalis turtschaninovii rhizome methanol extract were observed strong activity toward Tetranychus urticae. Catalpa ovata leaf and Ginkgo biloba leaf and stem methanol extracts were revealed high activity toward Nilaparvata lugens. Actium lap root methanol extract was observed moderate activity against Plutella xylostella. High or moderate insecticidal activity of plant extracts were listed in Fig.1. These plant resource, particularly plant methanol extract or insecticidal constituents, merit further as potential insect pest control agents or leads because of their great activity as a insecticide.
        105.
        2009.12 KCI 등재 구독 인증기관·개인회원 무료
        The effects of Ganoderma lucidum on glucose uptake was studied in L6 rat skeletal muscle cells. Glucose uptake in muscle cell was increased about 6-fold compared to control by mushroom extract treatment. This increasing effect to the glucose uptake was observed in muscle cells cultured with or without insulin. The levels of phosphor-acetyl CoA carboxylase were upregulated by G. lucidum extract treatment in insulinstimulated and basal culture conditions. However, G. lucidum extract did not affect protein kinaseB/Akt(Akt) level. Furthermore, the expression of phosphor-AMPactivated protein kinase(AMPK) was also up-regulated. AMPK is another regulatory protein in the glucose uptake pathway and energy metabolism. Thus, the treatment of G. lucidum extract in skeletal muscle cells increased the phosphorylation levels of AMPK and acetyl-CoA carboxylase, showing that the increase of glucose uptake by G. lucidum extract might be mediated via the activation of AMPK signaling pathway
        107.
        2009.10 구독 인증기관·개인회원 무료
        The traditional use of insects as food continues to be widespread in tropical and subtropical countries and to provide significant nutritional, economic and ecological benefits for rural communities. Specially, Bee brood serves as a food source to humans in many countries although limited data exists concerning its nutrient composition. Bee brood (pupa and larvae) were analyzed for Carbohydrate, Saturated fatty acid, Cholesterol, protein, fat, fiber, minerals, and vitamins. Bee brood was high in protein(46.4%~46.73%), fat(18.84%~ 20.75%),carbohydrate(24.66 %~35.79 %), Folic acid(222.30 ㎍/100g), and vitamins. Differentially, folic acid had been contained by high density in pupa of drone. While low in iron, bee brood was a good source of folic acid, and carbohydrate. The fat was composed mostly of saturated and mono-unsaturated fatty acids. The present data suggest bee brood to be an excellent source of many valuable nutrients including energy, amino acids, many essential minerals, and B-vitamins. These data suggest bee brood could be a valuable source of nutrients to various populations.
        108.
        2009.10 구독 인증기관·개인회원 무료
        The most effective methods against pine wilt disease (Bursaphelenchus xylophilus, PWD), black pine bast scale (Matsucoccus thunbergianae), pine needle gall midge (Thecodiplosis japonensis) is the trunk injection of insecticides. The period of trunk injection that was considered with ecology and physiology of pests such as pine wilt disease, black pine bast scale and pine needle gall midge, was applied from Dec. to next Feb. and June, Dec. respectively. And there are differences in quantities of being injected chemicals to pine trees by the period of trunk injection. Thus, we investigated to prevent the effect of insecticides, to estimate the effect under the trunk injection of insecticides for pine trees against pests by the injecting period and time, boring site, opening and shutting of injection site. On Pinuns thunbergii, it was examined to figure out the effect of insecticides by the injecting period, twice a month on a sunny day around 10 AM from January to September. Injecting of insecticides was tested at a dose of 5ml per cm dbh of a pine tree after boring with hand drill at 50 cm high from the ground. As a result, abmectin 1.8% EC and phospamidon 50% SL were injected over 90% of mortalities from the end of January to the middle of March but as time goes by, injecting insecticides tended to decrease. To compare the volume of injecting insecticides in a day, between 10 AM and 2 PM on February 23rd, abamectin 1.8% EC was injected at a dose of 5ml per pine trees with micro pipette after boring with a drill machine at 50 cm high from the ground. As a result, injecting insecticide of a pine which was injected around 10 AM was completely injected and about 90% of the insecticide was injected in case of a pine that was injected around 2 PM. Trunk injection of insecticides was examined to figure out differences of the volume of injected insecticides before and after rain. There was no difference not only the rainfall but also the bored direction.
        109.
        2009.10 구독 인증기관·개인회원 무료
        Trunk injection of nematicides is applied to prevent pine wilt disease(PWD). Although the trunk injection of nematicides is effective to PWD prevention, it is not effective to vector insects such as adults of M. alternatus and M. saltuarius. Thus, This study was investigated for the insecticidal activity and the effect of feeding deterrence by injecting to pine trees with acetamiprid. For screening effective nematicides, some insecticides were injected to pines on December 30th, 2008 and their insecticidal activities and feeding areas of M. alternatus and M. saltuarius were investigated in the insects breeding dishes (100× 40mm) where put on 1 to 2-year-old twig which was selected from injected pine trees in early June. As a result, insecticidal activity and feeding deterrence of acetamicprid were most effective. Feeding areas of M. alterantus adults, when tested with 1-year-old twig and 2-year-old twig of healthy pine trees, were 170.3±107.0 mm2 and 258.0±123.2 mm2 respectively. And Feeding areas of M. alterantus adults, when tested with 1-year-old twig and 2-year-old twig of pines injected at a dose of 0.3 ml per cm dbh of a pine tree with acetamiprid, were 57.7±72.3 mm2 and 65.7±51.2 mm2 respectively and their mortalities also were 0%, 28.6%. The feeding areas of M. alterantus adults tested with 1-year-old twig and 2-year-old twig of pine trees injected at a dose of 0.6 ml per cm dbh of a pine tree with acetamiprid, were not fed on it and the mortalities were 28.0%, 57.1% respectively. In case of the feeding areas of M. saltuarius adults, when tested with 1-year-old twig and 2-year-old twig of healthy pine trees, it was 112.±35.1 mm2 and 159.2±65.2 mm2 respectively. And the feeding areas of M. saltuarius adults, when tested with 1-year-old twig and 2-year-old twig of injected pine trees at a dose of 0.3 ml per cm dbh of a pine tree with acetamiprid were 0.61±0.0 mm2 and 8.1±12.4 mm2 and both mortalities were 23.1%. Although M. saltuarius adults, when tested with 1-year-old twig of a pine tree injected at a dose of 0.6 ml per cm dbh of a pine tree with acetamiprid, were not fed on it but M. saltuarius adults tested with 2-year-old twig of the same pine tree were 2.0±3.7 mm2 and their mortalities were 53.8%, 61.5% respectively. We investigated insecticidal activities, the effects of feeding deterrence of acetamiprid for vector insects where fed twigs of injected pines by stop up hole with a cork or not, and the trunk injection to pine trees at a dose of 0.5, 1 ㎖ per ㎝ dbh of a pine tree with acetamiprid on the early June. As a result, all of the vector insects were not fed and the feeding area was within 11 ㎟ and the mortality of M. alternatus was 70%.
        110.
        2009.08 구독 인증기관·개인회원 무료
        In the present study, we have developed a high-frequency plant regeneration system for Italian ryegrass via callus culture using mature seeds as explants. Optimal embryogenic callus induction was found to occur in MS medium containing 5 ㎎ 1?¹ 2,4-D, 0.5 ㎎ 1?¹ BA, 500 ㎎ 1?¹ L-proline, 1 g 1?¹ casein hydrolysate, 30 g 1?¹ sucrose, 7 ㎎ 1?¹ AgNO₃, 2 ㎎ 1?¹ CuSO₄ and solidified with 3 g 1?¹ Gelrite. The highest regeneration rate was obtained in MS medium containing 1 ㎎ 1?¹ 2,4-D, 5 ㎎ 1?¹ BA, 500 ㎎ 1?¹ L-proline, 1 g 1?¹ casein hydrolysate, 1 ㎎ 1?¹ thiamine-HCl, 30 g 1?¹ sucrose, 7 ㎎ 1?¹ AgNO₃, 2 ㎎ 1?¹ CuSO₄ and solidified with 3 g 1?¹ Gelrite. By using the most effective treatment determined for each parameter, the highest rates of embryogenic callus formation (48.9%) and regeneration (47.6%) were obtained with the Hwasan 101 cultivar. The overall plant regeneration rates of the examined cultivars ranged from 7.5% to 23.2%. Thus, optimization of regeneration frequency using mature seeds as explant material may offer a simple and efficient protocol for Italian ryegrass that may improve molecular breeding of this species.
        111.
        2009.08 구독 인증기관·개인회원 무료
        In the present study, genotypic variation of Agrobacterium-mediated transformation of Korean Italian ryegrass has been evaluated. Mature seed-derived calli of a total of seven cultivars were infected and co-cultured with Agrobacterium tumefaciens carrying the binary vector pCAMBIA1301, which contains a reporter gene (gus) and a plant selectable marker gene conferring resistance to hygromycin (hpt) in the T-DNA region. The effects of several factors such as callus type and callus age on transformation frequency and the expression of the GUS gene were investigated. The highest transformation frequency (6.7%) was obtained with the Hwasan 101 cultivar when 9-week-old calli (type-I) were inoculated with Agrobacterium. The overall transformation rates of the examined cultivars ranged from 0.4% to 6.7%. GUS histochemical assays, PCR, and southern analysis of transgenic plants demonstrated that transgenes were successfully integrated into the genome of Italian ryegrass. Thus, optimization of transformation frequency and selection of a suitable cultivar of Italian ryegrass may improve molecular breeding of this species.
        112.
        2009.05 구독 인증기관·개인회원 무료
        The current status of insect pollinator use was surveyed. Honeybee was larger than mason bee and bumblebee in average use area per farm household at kinds of insect pollinator. Insect pollinator was used at 19 crops. Among them, tomato was the most used crop, which was 44.9%, and in order to apple 26.7%, strawberry 13.1%, red-pepper 7.7% and watermelon 3.7%. In the use of insect pollinators, bumblebee, which was 56.9%, was higher than honeybee (31.3%) and mason bee (11.8%). The most farmers were a positive intention except for 1.5% of farmer in the use of insect pollinator for crop pollination. The best advantage in insect pollinator use was improvement of seed setting percentage, which was 28.3% and the worst problem was low activity at bad weather, which was 25.8%. And also, 97% of farmers have an intention to use continuously insect pollinator.
        113.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the effect of kilning condfition on the diastatic power and activities of protease, α-amylase, and β-amylase in rice malt. Common rice (Oryza sativa) was steeped at 30℃ for 50 h, germinated at 30℃ for 7 days, and kilned at 50℃ for 24 h. The moisture content and enzymatic activities were determined under various kilning times. As a result, the moisture content was reduced from 42.1 % to 3.9% after 24 h of kilning at 50℃. The protease activity of rice malt showed lower value than that of barley malt. All enzymatic activities were decreased during the kilning stage. Results indicated that after prolonged kilning at 50℃, the inactivation of hydrolytic enzymes might be occurred. Even though the amylolytic activity of malted rice showed low value, the rice malt shows the potential characteristics as ingredient for the brewing and cereal industries.
        4,000원
        114.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nowadays, Tra catfish fat is given attention as an appropriate material for biodiesel production in Vietnam. The aim of this work is to investigate the optimal conditions of refining biodiesel and recovering glycerin by the transesterification from Tra catfish fat using KOH catalyst. As our results, the yield of transesterification was achieved to 94.17% at 50℃ for 45 min with 6:1 molar ratio of methanol to fat in the presence of 0.8% KOH catalyst, and wherein the biodiesel was refined by washing with distilled water at 70℃ and dried in a microwave oven. The yield of raw glycerin recoveries from the transesterification process was 78.58%. The purity of raw glycerin was 84.14% by the conditions of neutralization state with H3PO4 solution (pH = 5), 70℃, and 60 min. Activated carbon (3.0 wt.%) was used for the bleaching process at 80℃ for 20 min. The biodiesel was obtained in accordance with for ASTM D 6751 (biodiesel standard). The ash and water of raw glycerins were 7.32 and 8.01%, respectively, and implied that the raw glycerin is very promising candidate to be used as a raw material for textile and cosmetic industries.
        4,000원
        115.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Transesterification of fat of Tra catfish with methanol in the presence of the KOH catalyst yields fatty acid methyl esters (FAME) and glycerol (GL). The effects of the reaction temperature and reaction time on rate constants and kinetic order were investigated. Three regions were observed. In the initial stage, the immiscibility of the Tra fat and methanol limited the reaction rate, hence this region was controlled by the mass transfer. Subsequent to this region, produced FAME like a co-solvent made the reaction mixture homogeneous, therefore the conversion rate increased rapidly so it was controlled by the kinetic parameters of the reaction until the equilibrium was approached in the final slow region. A second-order kinetic mechanism was proposed involving second regions for the forward reaction. The rate determining step for the overall KOH catalyzed-methanolysis of Tra fat was the conversion of triglycerides (TG) to diglycerides (DG). This rate constant was increased from 0.003 to 0.019min-1 when the reaction temperature was increased from 35 to 60℃. Its calculated activation energy was 14.379 (kcal.mol-1).
        4,200원
        116.
        2008.10 구독 인증기관·개인회원 무료
        Sacbrood virus(SBV) causes a fatal disease(sacbrood) of honeybee larvae, which fail to pupate, change color and shape, and finally die. The complete nucleotide sequence of SBV has recently been determined, and with these data, we now report a Reverse Transcription-PCR(RT-PCR) test for the direct, rapid, and sensitive detection of these viruses. To detect the SBV infection in Korea, we collect beekeepers from various apiaries, which the RT-PCR technique was used. And we designed SBV specific primers in conserved region of the viral genome in the GenBank database. We confirmed the SBV amplicon using cloning and sequence. Homology between determined sequences of SBV korean strain and published virus sequences were 97% in DNA sequence, and 100% in amino acid sequence. We describe the first time that presence of sacbrood virus(SBV) in Korea honey bee colonies using RT-PCR. We also developed and validated a RT-PCR assay for the detection of SBV in Korea.
        117.
        2008.10 구독 인증기관·개인회원 무료
        Viruses of the honeybee, Apis mellifera L. are known to reside at low levels in colonies, typically showing no apparent signs of infection. Chronic paralysis virus(CBPV) is known to induce significant losses in honey bee colonies. The pathology is characterized by clusters of trembling, flightless, crawling bees and by individual bees, sometimes hairless, standing at the hive entrance. A minusstrand-specific RT-PCR was used to assess viral replication. This is the first report on the infection of CBPV in Korea. Using (-)RT-PCR, 27 apiaries in korea were screened for the honeybee viruses, with positive colonies being analysed for viral genetic diversity. We got 550-nt PCR product from CBPV genomic RNA. Nucleotide sequences were aligned to the complete CBPV genomic RNA sequence deposited in the GenBank database and was revealed 96%(AM-CBPV) identity, respectively. Sequence comparison with other CBPV and honeybee virus.
        118.
        2008.10 구독 인증기관·개인회원 무료
        Mortality of honeybees is a serious problem that beekeepers have to face periodically in Korea and worldwide. The presence of RNA viruses, in addition to other pathogens may be one of its possible causes. In this work, we detected Deformed wing virus(DWV), Israle Acute Paralysis Virus (IAPV), Black queen cell virus (BQCV), Cloudy wing virus(CWV), Kashmir bee virus(KBV), Sacbrood virus(SBV), Chronic bee paralysis virus(CBPV) in samples of korea honeybees with or without Varroa destructor and Nosema apis. The detection of viruses in all provinces, simultaneous co-infection of colonies by several viruses and the fact that 96.3% of the samples were infected with one or more virus, indicates they are widely spread in the region. Using uniplex and multiplex RT-PCR we screened honey bee colonies for the presence of several bee viruses, including DWV, IAPV, BQCV, KBV, CWV, and described the detection of mixed virus infections in bees from these colonies. Conclusively, investigated disease of the bee, and confirmed new virus that lead to bee disease, this is thought by valuable thing as data for development of beekeeping industry such as CCD(Colony Collapse Disorder)'s cause searching examination.
        119.
        2008.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cellulose nanofibers from microfibril cellulose (MFC) was prepared by hydrobromic acid (HBr) treatment at different concentrations. Polyvinyl alcohol (PVA) composite films at various loading level of nanofibers were manufactured by a film casting method. The analysis of degree of polymerization (DP), crystallinity (Xc) and molecular weight (Mw) of cellulose after acid treatment was conducted. The mechanical and thermal properties of the cellulose nanofibers reinforced PVA films were characterized using tensile tests and thermogravimetric analysis (TGA). The DP and Mw of MFC by HBr hydrolysis considerably decreased, but Xc showed no significant change. After acid hydrolysis, the diameter of cellulose nanofibers was in the range of 100 to 200 nm. The thermal stability of the films was steadily improved with the increase of nanofiber loading. There was a significant increase in the tensile strength of PVA composite films with the increase in MFC loading. Finally, 5 wt.% nanofiber loading exhibited the highest tensile strength and thermal stability of PVA composite films.
        4,000원
        120.
        2008.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The fat of Tra and Basa catfish (Mekong Delta, Viet Nam) was evaluated for the first time as the potential feedstock for biodiesel production, due to its abundance, availability and cheap cost. The unsaturated fatty acid contents of Tra and Basa fat were 57.97% and 64.17%, respectively. Biodiesel was prepared from Tra and Basa fat by methanolysis reaction using alkali catalysts like sodium hydroxide and potassium hydroxide. Effects of various process parameters on biodiesel production, such as molar ratio of methanol to fat, catalyst concentration, temperature and time were investigated. As those results, the transesterification can be performed under moderate conditions, and the biodiesel yields were shown more than 90%. KOH catalyst was the best catalyst for biodiesel production from both Basa and Tra fat. As the feedstock aspect, Basa fat was indicated more efficiency than that of Tra fat. The maximum yield could be achieved by the transesterification from Basa fat with 5:1 molar ratio of methanol to fat, 0.8% KOH catalyst, 50℃, and 50 min. For Tra fat, the optimal condition were at 6:1 molar ratio of methanol to fat, 0.8% KOH catalyst, 50℃, and 45 min. Nowadays, due to cheaper cost and abundance, Tra fat is a promised resource for cheap biodiesel production in Viet Nam.
        4,600원