• Title, Summary, Keyword: EST

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Development of Acaricidal Resistance and Esterase Isozyme of Tetranychus urticae (Acarina : Tetranychidae) (점박이응애의 살비제저항성 발달과 Esterase Isozyme에 관한 연구)

  • 김상수;이승찬
    • Korean journal of applied entomology
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    • v.29 no.3
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    • pp.170-175
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    • 1990
  • These studies were conducted to examine the mechanism of acaricidal resistance in the twospotted spider mite (Tetranychus urticae Koch). The resistant strains were obtained by succssive selection of five acaricides including carbonphenothion and ethion of organophosphorus compound, dicofol of organochlorine compound, cyhexatin of compound and biphenthrin of synthetic pyrethroid. Esterase isozymes were separated by polyacrlyamide gel susceptible strains. The differences of the esterase isozymes of the resistant strains were Est. 1, Est. 3 in the carbonphenothion-selected strain, Est. 3 in the ethion- and the cyhexatin-selected strains, Est. 1, Est. 3, Est. 7 in the dicofol-selected strain, Est. 7 in the biphenthrin-selected strain as compared to the susceptible strain. With the difference of electrophoretic bands and their activities, esterases were related to the resistant mechanism of tested acaricides.

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Esterase Isozyme Variation in the Tissues of Glycine soja S. and Z. , Vigna vexillata var. tsusimensis Matsmura , and Trifolium repens L. in Korea (돌콩 , 돌동부 , 화이트 클로버의 조직별 Esterase Isozyme 변이에 관한 연구)

  • 이성규
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.12 no.4
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    • pp.253-259
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    • 1992
  • The esterase isozyme in tissue of wild legume plants were separated by horizontal starch gel electrophoresis. Extracts used in this study were prepared from fully expanded young leaf, cotyledon and radicle of seedling and root-nodule of Glycine sola, Vigna vexillata var. tsuscmensis and Trifoliwn repens. The results are as follows; 1. Each tissue examined had a characteristic banding pattcrn. Number of bands in each species, G. soja, V. vexillata, and T . repens, were 14, 8 and 1 1 bands, respectively. And difference in esterase isozyme bands were greater from tissue to tissue than difference between habitat. 2. Est-I, Est-2. Est-3 and Est-4 in G. soja, Est-I in V. vexillata and Est-l and Est-2 in T. repens showed strong cnzyme activity than other enzyme. 3. Esterase isozyme variation in G. soja and T . repens showed more variety than V. vexillata. This is resulted from many genotypic differences within species. 4. The main enLyme among thc esterase isozyme were Est-I. Est-2, Est-3 and Est-4.

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A Study on the Change of Electrical Characteristics in the EST(Emitter Switched Thyristor) with Trench Electrodes (EST(Emitter Switched Thyristor) 소자의 트랜치 전극에 의한 특성 변화 연구)

  • 김대원;성만영;강이구
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.3
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    • pp.259-266
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    • 2004
  • In this paper. a new two types of EST(Emitter Switched Thyristor) structures are proposed to improve the electrical characteristics including the current saturation capability. Besides, the two dimensional numerical simulations were carried out using MEDICI to verify the validity of the device and examine the electrical characteristics. First, a vortical trench electrode EST device is proposed to improve snap-back effect and its blocking voltage. Second, a dual trench gate EST device is proposed to obtain high voltage current saturation characteristics and high blocking voltage and to eliminate snap-back effect. The two proposed devices have superior electrical characteristics when compared to conventional devices. In the vertical trench electrode EST, the snap-back effect is considerably improved by using the vertical trench gate and cathode electrode and the blocking voltage is one times better than that of the conventional EST. And in the dual trench gate EST, the snap-back effect is completely removed by using the series turn-on and turn-off MOSFET and the blocking voltage is one times better than that of the conventional EST. Especially current saturation capability is three times better than that of the other EST.

Signal Detection for 8 PSK and 16 QAM in EST-Based Modulation (EST기반 변조에서 8 PSK와 16 QAM 에 대한 신호 검출)

  • Kwon, Byung-Uk;Hwang, Tea-Won
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.11C
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    • pp.682-693
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    • 2011
  • Energy spreading transform (EST) based modulation is an effective technique to combat frequency-selective fading in broadband wireless communication. It performs close to the inter-symbol interference (ISI)-free matched filter bound (MFB) only at the complexity of a linear detector. Originally, EST-based modulation has been proposed for QPSK. However, to fully utilize the capacity of multipath fading channels, higher-order modulations are also necessary. In this paper, we review the EST based modulation that has originally been proposed for QPSK and discuss its extension to 8 PSK and 16 QAM. The performance of the extended system is verified through simulation in Proakis B and 8-tap fading channel. The EST based modulation for 8 PSK shows the performance which is very close to MFB and the EST based modulation for 16 QAM shows the performance gap between its receiver and MFB.

A Novel Esterase from a Marine Metagenomic Library Exhibiting Salt Tolerance Ability

  • Fang, Zeming;Li, Jingjing;Wang, Quan;Fang, Wei;Peng, Hui;Zhang, Xuecheng;Xiao, Yazhong
    • Journal of Microbiology and Biotechnology
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    • v.24 no.6
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    • pp.771-780
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    • 2014
  • A putative lipolytic enzyme gene, named as est9x, was obtained from a marine microbial metagenome of the South China Sea. Sequence analysis showed that Est9X shares lower than 27% sequence identities with the characterized lipolytic enzymes, but possesses a catalytic triad highly conserved in lipolytic enzymes of the ${\alpha}/{\beta}$ hydrolase superfamily. By phylogenetic tree construction, Est9X was grouped into a new lipase/esterase family. To understand Est9X protein in depth, it was recombinantly expressed, purified, and biochemically characterized. Within potential hydrolytic activities, only lipase/esterase activity was detected for Est9X, confirming its identity as a lipolytic enzyme. When using p-nitrophenol esters with varying lengths of fatty acid as substrates, Est9X exhibited the highest activity to the C2 substrate, indicating it is an esterase. The optimal activity of Est9X occurred at a temperature of $65^{\cric}C$, and Est9X was pretty stable below the optimum temperature. Distinguished from other salt-tolerant esterases, Est9X's activity was tolerant to and even promoted by as high as 4 M NaCl. Our results imply that Est9X is a unique esterase and could be a potential candidate for industrial application under extreme conditions.

Changes in Esterase Isozyme Activity after Selective Diets and Insecticides in Monochamus saltuarius (Gebler) Larva (북방수염하늘소(Monochamus saltuarius) 유충의 먹이와 살충제 처리에 따른 소화 효소의 활성 변화)

  • Cho, Sae-Youll;Kim, Ju-Hyun;Park, Yong-Chul
    • The Korean Journal of Pesticide Science
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    • v.11 no.3
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    • pp.171-178
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    • 2007
  • Esterase isozymes were extracted from final instar larvae of M. saltuarius treated with selective diets and inhibitors. Twenty esterase isozymes were separated on 12% native-PAGE gel and stained with three different substrates(${\alpha}$-naphthyl acetate, ${\beta}$-naphthyl acetate, or ${\alpha}$-naphthyl butyrate). Interestingly, the isozymes of Est7(${\alpha}$-naphthyl acetate and ${\alpha}$-naphthyl butyrate) and Est6(${\beta}$-naphthyl acetate) were specifically activated in final instar larvae fed with the bark of Pinus koraiensis. However, we could not find any band from substrate ${\beta}$-naphthyl stearate. The esterase activities of Est3, Est6, and Est7 were inhibited by organophosphate and carbamate insecticides. In addition, The esterase activities of Est4, Est6, and Est7 were also inhibited by eserine. However, inhibition of esterase activities in methoprene, bornyl acetate, linal, cineol, and citral was not observed. However, It is necessary to reconfirm these results in vivo.

Changes in Esterase Isozyme Activity After Pesticides Treatment in Digestive Juice of Monochamus saltuarius (Gebler) Adult (북방수염하늘소(Monochamus saltuarius) 성충의 살충제 처리에 따른 소화 효소의 활성 변화)

  • Park, Yong-Chul;Cho, Sae-Youll
    • The Korean Journal of Pesticide Science
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    • v.11 no.3
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    • pp.179-185
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    • 2007
  • Esterase isozymes were investigated from digestive juice of M. saltuarius adults after pesticide treatment. Twelve esterase isozymes were separated on 12% native-PAGE gel and stained with three different substrates(${\alpha}$-naphthyl acetate, ${\beta}$-naphthyl acetate, and ${\alpha}$-naphthyl butyrate). Interestingly, the isozyme of Est1(${\alpha}$-naphthyl acetate) was strongly inhibited by the carbofuran and methomyl. The Est1 activity was completely inhibited by the chlorpyrifos and partially inhibited by methidation about 70 %. In addition, eserine suppressed esterase isozyme activities of Est1 about 70% and isozyme activities of Est2, Est3, and Est4 were weakly inhibited. ${\alpha}$-pinene did not suppressed esterase isozyme activities but activities of esterases were very weakly inhibited in camphor and bornyl acetate.

Genotypic Variation of Esterase Isozyme in Breeding Lines of Two-rowed Barley by Electrophoretic Banding Pattern (전기영동 패턴에 의한 2조보리 계통의 Esterase 동위효소 유전자형 변이분석)

  • 박광근;최홍집;이종호;서세정;김재철;남중현;김상효
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.47 no.6
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    • pp.465-470
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    • 2002
  • This study presents results of electro-phoretically detectable isozyme variation in Crossing Block (CB) lines of two-rowed barley maintained by the National Crop Experiment Station. The specific objectives were to determine allelic frequencies at the four Est loci(Est1, Est2, Est4, and Est5) and their distribution over 380CB lines of two-rowed barley. A total of 17 alleles were detected over the four Est loci in these lines. There were 4 alleles (Pr, Al, Ca, and Af at the Est1 locus and their frequencies were 69.7, 1.1, 28.4, and 0.8%, respectively. At the Est2 locus, 5 different alleles (Dr, Fr, Sp, Un and a recessive null allele) were detected and their frequencies were 2.9,84.5,0.5,2.1, and 10%, respectively. four alleles (Nz, Su, At, and null were detected at the Est4 locus and the allelic frequency of Su was about 84%. Four alleles(Mi, Pi, Te, and a null allele(od)) were detected at the Est5 locus and their frequencies were 34.2, 61.0, 2.4, and 2.4%, respectively. Based on the allelic frequencies over the four Est loci, 380 CB lines were classified into 25 genotypes. The most frequent genotypes were G1(Pr-Fr-Su-Mi) and G2(Pr-Fr-Su-Pi), and their frequencies were 28.1 and 39.5%, respectively. The frequencies of other genotypes were less than 10%.

A New EST with Dual Trench Gate Electrode (DTG-EST)

  • Kim, Dae-Won;Sung, Man-Young;Kang, Ey-Goo
    • Transactions on Electrical and Electronic Materials
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    • v.4 no.2
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    • pp.15-19
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    • 2003
  • In this paper, the new dual trench gate Emitter Switched Thyristor (DTG-EST) is proposed for improving snap-back effect which leads to a lot of serious problems of device applications. Also the parasitic thyristor that is inherent in the conventional EST is completely eliminated in this structure, allowing higher maximum controllable current densities for ESTs. The conventional EST exhibits snap-back with the anode voltage and current density 2.73V and 35A/$\textrm{cm}^2$, respectively. But the proposed DTG-EST exhibits snap-back with the anode voltage and current density 0.96V and 100A/$\textrm{cm}^2$, respectively.