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Preparation and Dielectric Properties of LCP and BaTiO3 Composites (LCP(Liquid Crystal Polymer)와 BaTiO3복합체의 제조 및 유전특성)

  • 윤기현;이승주;양병덕;김종희
    • Journal of the Korean Ceramic Society
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    • v.40 no.12
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    • pp.1183-1188
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    • 2003
  • LCP (Liquid Crystal Polymer)/BT(BaTiO$_3$) composite was prepared by mixing LCP varnish and BT slurry. And the effect of the composition of LCP/BT composites and the size of BT powder on dielectric properties of LCP/BT composite were investigated. The dispersion properties of BT slurries were also studied as a function of volume fraction of dispersant, GLYMO (3-glycidyloxypropyltrimethoxysilane) added to various sized BT powders. The quantity of optimum dispersant in BT slurry decreased with an increase of BT powder size because of the decrease of specific surface area of BT powder. LCP/BT composite sheet was prepared by tape-casting method with mixing BT slurry and LCP varnish. The dielectric constant of the composites increased from 34.3 to 44.1 and their dielectric loss increased from 0.05 to 0.063 as the size of BT powder increased from 100 nm to 500 nm.

Development of "Bt-Plus" Biopesticide Using Entomopathogenic Bacterial (Xenorhabdus nematophila, Photorhabdus temperata ssp. temperata) Metabolites (곤충병원세균(Xenorhabdus nematophila, Photorhabdus temperata ssp. temperata)의 대사물질을 이용한 "비티플러스" 생물농약 개발)

  • Seo, Sam-Yeol;Kim, Yong-Gyun
    • Korean journal of applied entomology
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    • v.50 no.3
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    • pp.171-178
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    • 2011
  • Bacillus thuringiensis (Bt) is a bacterial biopesticide against insect pests, mainly lepidopterans. Spodoptera exigua and Plutella xylostella exhibit significant decreases in Bt susceptibility in late larval instars. To enhance Bt pathogenicity, we used a mixture treatment of Bt and other bacterial metabolites which possessed significant immunosuppressive activities. Mixtures of Bt with culture broths of Xenorhabdus nematophila (Xn) or Photorhabdus temperata ssp. temperata (Ptt) significantly enhanced the Bt pathogenicity against late larval instars. Different ratios of Bt to bacterial culture broth had significant pathogenicities against last instar P. xylostella and S. exigua. Five compounds identified from the bacterial culture broth also enhanced Bt pathogenicity. After determining the optimal ratios, the mixture was applied to cabbage infested by late instar P. xylostella or S. exigua in greenhouse conditions. A mixture of Bt and Xn culture broth killed 100% of both insect pests when it was sprayed twice, while Bt alone killed less than 80% or 60% of P. xylostella and S. exigua, respectively. Other Bt mixtures, including Ptt culture broth or bacterial metabolites, also significantly increased pathogenicity in the semi-field assays. These results demonstrated that the Bt mixtures collectively names "Bt-Plus" can be developed into potent biopesticides to increase the efficacy of Bt.

한국의 BT 시대 열리다

  • Korean Federation of Science and Technology Societies
    • The Science & Technology
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    • v.35 no.4
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    • pp.43-70
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    • 2002
  • BT산업의 새시대 - BT산업은 21세기 국가성장 동력, IT와 같이 경쟁력 확보 전망 밝아/우리나라 BT산업현황[의약분야] - 신약 연구와 결과 내용 아직 걸음마 단계, 기반시설 확충ㆍ투자ㆍ우수인력 확보 시급/우리나라 BT산업현황[미생물 분야] - 생물정보학 전문가ㆍ전산시스템 취약, 유전체 정보관련 산업 활로 모색 활발/우리나라 BT산업현황[농업분야] - 지원 취약, 소비자 거부감 겹쳐 발전 애로/우리나라 BT산업현황[축산분야] - 전통육종기술 접목 가축개량 극대화/우리나라 BT산업현황[생물정보(BT+IT) 분야] - 인프라구축단계, 벤처중심 연구 활기/BT와 윤리 - 의식없이 문제제기 불안감 조성은 곤란, BT시대 맞는 새로운 윤리관 확립 필요/선진국의 BT산업 - 의약품 제조분야 치열한 연구개발 경쟁, 대형 제약회사 앞다퉈 BT기업과 연대

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Effects of N-/C-Terminal Extra Tags on the Optimal Reaction Conditions, Activity, and Quaternary Structure of Bacillus thuringiensis Glucose 1-Dehydrogenase

  • Hyun, Jeongwoo;Abigail, Maria;Choo, Jin Woo;Ryu, Jin;Kim, Hyung Kwoun
    • Journal of Microbiology and Biotechnology
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    • v.26 no.10
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    • pp.1708-1716
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    • 2016
  • Glucose dehydrogenase (GDH) is an oxidoreductase enzyme and is used as a biocatalyst to regenerate NAD(P)H in reductase-mediated chiral synthesis reactions. In this study, the glucose 1-dehydrogenase B gene (gdhB) was cloned from Bacillus thuringiensis subsp. kurstaki, and wild-type (GDH-BTWT) and His-tagged (GDH-BTN-His, GDH-BTC-His) enzymes were produced in Escherichia coli BL21 (DE3). All enzymes were produced in the soluble forms from E. coli. GDH-BTWT and GDH-BTN-His showed high specific enzymatic activities of 6.6 U/mg and 5.5 U/mg, respectively, whereas GDH-BTC-His showed a very low specific enzymatic activity of 0.020 U/mg. These results suggest that the intact C-terminal carboxyl group is important for GDH-BT activity. GDH-BTWT was stable up to 65℃, whereas GDH-BTN-His and GDH-BTC-His were stable up to 45℃. Gel permeation chromatography showed that GDH-BTWT is a dimer, whereas GDH-BTN-His and GDH-BTC-His are monomeric. These results suggest that the intact N- and C-termini are required for GDH-BT to maintain thermostability and to form its dimer structure. The homology model of the GDH-BTWT single subunit was constructed based on the crystal structure of Bacillus megaterium GDH (PDB ID 3AY6), showing that GDH-BTWT has a Rossmann fold structure with its N- and C-termini located on the subunit surface, which suggests that His-tagging affected the native dimer structure. GDH-BTWT and GDH-BTN-His regenerated NADPH in a yeast reductase-mediated chiral synthesis reaction, suggesting that these enzymes can be used as catalysts in fine-chemical and pharmaceutical industries.

Molecular Cloning and Characterization of Chymotrypsin Inhibitor and Chitin-Binding Protein Homologs from the Bumblebee Bombus terrestris

  • Qiu, Yuling;Yoon, Hyung-Joo;Jin, Byung-Rae
    • International Journal of Industrial Entomology
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    • v.25 no.1
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    • pp.115-121
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    • 2012
  • The bumblebee Bombus terrestris is widely used in greenhouses to pollinate crops. Here, we report the molecular cloning and characterization of chymotrypsin inhibitor and chitin-binding protein homologs from B. terrestris. Two cDNAs encoding chymotrypsin inhibitor (Bt-CI) and chitin-binding protein (Bt-CBP) homologs were cloned from B. terrestris. Gene sequence analysis showed that Bt-CI gene consists of three exons encoding 75 amino acids, including a predicted 20-amino acid signal peptide, while Bt-CBP consists of two exons encoding 78 amino acids, including a predicted 26-amino acid signal peptide. The mature Bt-CI and Bt-CBP peptides contain ten and six conserved cysteine residues, respectively. Database searches using the deduced sequences of Bt-CI and Bt-CBP showed similarity to those from B. impatiens (96% peptide sequence identities). Bt-CI and Bt-CBP were expressed in both the venom gland and fat body of B. terrestris worker bees. The recombinant Bt-CI and Bt-CBP peptides were expressed in baculovirus-infected insect cells. Taken together, our findings describe the molecular characterization of Bt-CI and Bt-CBP from B. terrestris.

Characterization of a δ-endotoxin produced by Bacillus thuringiensis BT-1, BT-2. (Bacillus thuringiensis BT-1, BT-2가 생산하는 δ-endotoxin의 특성 규명)

  • Kim, Young-Min;Choi, Hong-Seo;Chung, Kun-Sub
    • Journal of Life Science
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    • v.17 no.5
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    • pp.658-663
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    • 2007
  • Bacillus thuringiensis is a well-known species of entomophathogenic bacteria that is widely used as a biopesticide against many insect pests. It produces parasporal crystals ($\delta$-endotoxin) and endospores during sporulation. In this report, the $\delta$-endotoxin produced by Bacillus thuringiensis BT-1 and BT-2 were characterized by Scanning Electron Microscope(SEM), Transmission Electron Microscope(TEM), SDS-PACE, and solubilization activity by alkaline solution. BT-1, BT-2 were cultured in the GBY medium, and the $\delta$-endotoxin of them was purified with discontinuous sucrose density gradient centrifugation. Their $\delta$-endotoxin was observed by SEM and TEM. Morphologically, the $\delta$-endotoxin of BT-1 was a square and flat type, whose size was $1.73{\mu}m{\times}0.7{\mu}m$, and the $\delta$-endotoxin of the BT-2 was spherical form whose size was $1.1{\mu}m{\times}0.9{\mu}m$ determined by SEM and TEM. The $\delta$-endotoxin of the BT-1 was composed of 28 kDa and 21 kDa, however, it of the BT-2 was composed of 50 kDa, 35 kDa, and 22 kDa bands determined by SDS-PACE. The purified crystals of BT-1 and BT-2 were dissolved gradually in alkaline solution as time goes by, and it was perfectly dissolved after 3 hours. It is supposed that the $\delta$-endotoxin of crystal was converted to a state of activation in the course of time in the intestines of insect.

Characterization of relationship between particle size and powder properties for $BaTiO_3$ ($BaTiO_3$의 입도와 분체특성과의 상관 관계 연구)

  • Chun, M.P.;Cho, J.H.;Kim, B.I.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.15 no.6
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    • pp.244-251
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    • 2005
  • The relationship between particle size of hydro-thermally synthesized barium titanate powders (BT01, BT02, BT03, BT04, BT05) and the powder properties was investigated by means of particle size, specific surface area, zeta potential, XPS, XRD and SEM. Particle size determined by laser light scattering is closely related with specific surface area and the tetragonality (c/a) obtained from XRD. The specific surface area of the samples inversely decreased with increasing particle size except BT03 powder. BT03 sample showed higher surface area than BT04 sample of equivalent particle size, which was attributed mostly to the agglomeration of particles in terms of SEM image and XRD analysis. Zeta potential increased with increasing particle size with the exception of BT02 and BT03 which showed larger minus value of zeta potential in comparison with other BT powders. Beta potential results of BT02 and BT03 are considered to be related with the dissolution of $Ba^{2+}$ ion in these powers which was examined by XPS.

Combination Effects of Bacillus thuringiensis and Sophora Extract on Spodoptera exigua (Bacillus thuringiensis와 고삼추출물 혼합처리에 의한 파밤나방 방제효과)

  • Han, Ji-Hee;Kim, Yoon-Ji;Jeong, Hye-Ju;Kim, Jeong-Jun;Lee, Sang-Yeob;Kim, Dayeon;Ahn, Seong-Ho
    • Korean Journal of Organic Agriculture
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    • v.24 no.4
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    • pp.821-831
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    • 2016
  • This study was conducted to identify the insecticidal effect of a mixture of sophora extract and Bacillus thuringiensis against Spodoptera exigua on potted chinese cabbage in both laboratory and plastic house condition. In laboratory condition, mortality of larvae by BT ($1{\times}10^5$, $1{\times}10^6$, $1{\times}10^7cfu\;ml^{-1}$) alone was 27.5%, 51.3% and 92.5%, respectively, which was depend upon concentration of BT. Control efficacy of the mixture of BT and sophora extract was 98.8%, 88.8% and 91.3% which was higher than BT treatment only. The mixture of sophora and lower BT concentration was showed more increase of control efficacy. Anti-feedant effect by BT was depend on concentration of BT. At field experiment, the mixture of BT and sophora extract appeared higher mortality (72.2%, 67.8%, 61.1%) than BT treatment only (14.4%, 26.7%, 66.7%) similar with laboratory experiment. The mixture was less affected by environmental condition at field than BT only. Therefore, for effective control of beet armyworm without possibility to develop resistance against BT at farm, treatment of the mixture of sophora extract (0.033%) and BT ($1{\times}10^5cfu\;ml^{-1}$) would be considered more effective than BT treatment only.

Comparative Performance of Broilers Fed Diets Containing Processed Meals of BT, Parental Non-BT Line or Commercial Cotton Seeds

  • Elangovan, A.V.;Mandal, A.B.;Johri, T.S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.16 no.1
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    • pp.57-62
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    • 2003
  • An effort was made to assess comparative production performance in broiler chickens fed diets containing solvent extracted cottonseed meal (CSM) processed from BT and Parental Non-BT lines. Processed meal of national check and commercial produce cottonseeds were also used for comparison. The free gossypol contents were 0.02, 0.02, 0.44 and 0.03% in meals of BT, Parental Non-BT, national check and commercial produce cottonseeds, respectively. Day-old broiler chicks (n=243) were divided to 27 groups of 9 each. Nine dietary treatments (iso-nitrogenous, 23% CP and iso-caloric, 2,800 kcal ME/kg) were formulated viz., D1 (control, soybean meal-SBM based), D2 and D3 (BT CSM at 10% of diet with and without additional iron), D4 and D5 (non-BT CSM with and without additional iron), D6 and D7 (national check CSM with or without additional iron), and D8 and D9 (commercial produce CSM with or without additional iron at 2 ppm for every 1 ppm of free gossypol, respectively). Each dietary treatment was offered to three replicated groups up to 6 weeks of age. At the end of 6 weeks of age, 10 birds were taken out randomly from each treatment and were sacrificed to study carcass traits, organs' yield and histo-pathological changes in vital organs. The broiler chickens received CSM processed from BT (D2, 1,753 g and D3, 1,638 g) and Parental Non-BT (D4, 1,653 g and D5, 1,687 g) with or without additional Fe grew at same rate as observed in soybean meal (solvent ext.) based diet (D1, 1,676 g). The feed intake and feed conversion efficiency (feed: gain) in these dietary treatments (BT, non-BT line based diets) also did not differ significantly (p>0.05) from control diet. Similar observation was also observed in dietary treatments (D8 and D9) containing solvent extracted cottonseed meal of commercial produce origin. However, a decrease (p<0.05) in body weight gain and feed intake was observed in D6 containing national check CSM with high gossypol content. Addition of Fe in the diet (D7) improved (p<0.05) feed intake and weight gain but not to the extent as observed in diets containing BT, parental non-BT, and commercial produce CSM or control. However, any type of CSM did not affect feed conversion efficiency when fed with or without additional iron. The carcass characteristics in terms of dressing percentage, liver weight and heart weight was not significantly (p>0.05) different between the treatments. The eviscerated yields emanated from diets containing either BT, non-BT or commercial produce were statistically similar to control. However, eviscerated yield of broilers fed national check CSM with or without iron supplementation was lower (p<0.05) than BT cotton with Fe supplementation and commercial produce CSM. The study envisaged that BT, parental non-BT and commercial produce solvent extracted cottonseed meal can be included at 10% in soybean meal based broiler diet replacing soybean meal and rice bran without additional iron.

An Empirical Study on the Characteristics of BT-based Converging Technology Market in Korea (우리나라 BT 융합기술 시장의 특성에 관한 실증연구)

  • Choi, Na-Lin;Hyun, Byung-Hwan;Kim, Pang-Ryong
    • Journal of Korea Technology Innovation Society
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    • v.15 no.2
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    • pp.299-322
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    • 2012
  • Biotechnology is considered a new propeller to national economic growth. Although BT-based converging technology is one of keywords in nowadays, few studies analyze the characteristics of Korean BT convergence market. This study has conducted the analysis of BT-based converging technology market by using patent database in KIPO (Korean Intellectual Property Office) from 2000 to 2010. We, especially, have classified BT convergence into homogeneous and heterogeneous ones, and compare the nature of BT convergence market with that of non-convergence one. To achieve the object of this study, the following methods are used: concentration across IPC technological classes; concentration of patenting activity across firms; PFS (Patent Family Size) index. Furthermore, according to FOS technology-industry table, we have intended to find new converging industry of BT heterogeneous converging technologies. As very few studies have focused on Korean converging technology market so far, this analysis is considered to be meaningful. It is found that the market of BT converging technology is rather robust than that of BT non-converging one, which refers that BT convergence shows the tendency of concentration towards few technologies by few conglomerate firms in Korea. Meanwhile, we have derived a BINET keyword map to research the convergence of sub-technologies in detail and the related industries. We expect the implications of this study to be utilized in establishing the BT-based converging technology policy.

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