• Korean journal of applied entomology
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• v.61 no.1
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• pp.101-108
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• 2022

Because of their specificity to target insects and relatively low toxicity to non-target organisms, insect growth regulators (IGRs) have been regarded as attractive alternatives to chemical insecticides. Commercially available IGRs are classified into juvenile hormone agonists (JHAs), ecdysone agonists (EAs), and chitin synthesis inhibitors (CSIs) according to their mode of action. Recently, JH-mediated interaction of methoprene-tolerant (Met), which is JH receptor, and its binding partners have been replicated in vitro using yeast cells transformed with the Met and FISC/CYC genes of A. aegypti. Using this in vitro yeast two-hybrid β-galactosidase assay, juvenile hormone antagonists (JHANs) have been identified from various sources including chemical libraries, plants, and microorganisms. As juvenile hormone (JH) is an insect specific hormone and regulates development, reproduction, diapause and other physiological processes, JHANs fatally disrupt the endocrine signals, which result in abnormal development and larval death. These results suggested that JHANs could be efficiently applied as IGR insecticides with a broad insecticidal spectrum. This review discuses JH signaling pathway mediated by Met and future prospects of JHANs as environmentally benign IGR insecticides.

• The Korean Journal of Zoology
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• v.35 no.2
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• pp.173-182
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• 1992

흰쥐에 Spirometro rrinoce측 제3기 유충(고충 sparganum)이 감염되었을때 유충에서 생성된 성장호르몬 유사물질이 흰쥐 성장에 미치는 영향을 조사하기 위하여, 감염 기일이 경과에 따라 흰쥐의 뇌하수체와 유충의 체내에서 성장호르몬 분비세포를 면역조직화학염색으로 검색하였다. 유충의 표피와 표피성 근육층 및 근질 근육층에서 면역반응성을 띄는 성장 호르몬이 동정되었으며 감염시기의 경과에 따라 성장호르몬 분비세포의 수가 점차 증가하였다. 이와는 대조적으로 흰쥐의 뇌하수체에서는 성장호르몬 분비세포의 수가 감염 기일의 경과에 따라 정상대조군에 비하여 점차 감소 하였으며, 감염후 3개월이 경과되면 다시 증가하여 정상대조군의 수준으로 회복되었다. 또한 유충에 감염된 기일의 경과에 따른 횐쥐의 혈중 성장호르몬 농도변화를 dot-ELISA 방법으로 추정한 결깍 정상대조군의 성장호르몬의 양과 유의한 차이는 없었다. 결론적으로 유충의 체내에서 생성된 성장호르몬 유사물질이 전이숙주인 흰쥐의 성장을 유도할 것으로 사료된다.

• Korean journal of applied entomology
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• v.31 no.2
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• pp.144-152
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• 1992

The juvenile hormone(JH) titers and juvenile hormone esterase (JHE) activities were mea¬sured in larval homogenates of the chestnut gall waL,J, Dryocosmus kuriphilus Yasumatsu, parasiting a susceptible and two resistant chestnut ( Cheuk-Pa, and Dan- Tak) varieties by GLC, Galleria wax test and Liquid scintilation counter. JH of the chestnut gall wasp was identified as JH- I. Their juvenile hormone titers were 35,800 GU/g(Cheuk-Pa), 30,900 GU/g (Dan-Tak), and 28,600 GU/g(susceptible variety). The juvenile hormone esterase activities were 1.48 n mole/min/ml(Cheuk-Pa), 1.63 n mole/min/ml(Dan- Tak), and 1.89 n mole/mini ml(susceptible variety). JH titer activity of the chestnut gall wasp parasiting resistant varie¬ties were higher than that from susceptible, whereas their JHE activity was higher in those from susceptible variety than those from resitant varieties. JH titer and JH specific esterase activity was inversely proportional.

• Korean journal of applied entomology
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• v.30 no.4
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• pp.258-264
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• 1991

Studies were carried out to investigate effects of temperature and photoperiod on diapause induction and of juvenile hormone III and 20-hydroxyecdysone treatment on diapausing adults of the alder leaf beetle, Agelastica coerulea Baly(Chrγsomelidae: Coleoptera). Its life cycle and ovarian development in adults were also observed. The beetle had one year life cycle with egg, larval, pupal and adult periods being 7-10, 19-21, 14-15 days and about 10 months, r respectively. All adults showed a diapause syndrome when the larvae were reared at $20^{\circ}C$ or $25^{\circ}C$ in combination of photoperiods of 16L/8D, 12L/12D, or 8L/16D. Their ovarioles did not s show any development of vitellogenesis before or during diapause and even when exposed at $15^{\circ}C$ after overwintering. When diapausing adults were treated with JH III they resumed feeding and laid several eggs and broke diapause condition temporally. But diapausing adults treated with 20-hydroxyecdysone did not show any response.

• Korean journal of applied entomology
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• v.31 no.4
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• pp.475-479
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• 1992

The non-steroidal ecdysone agonist RH 5849 showed almost similar LC.o values( 18.1-26.5 ppm) at all stages of larval development of the tobacco cutworm, Spodoptera litura, when treated by a leaf-disk dipping method. The feeding-inhibition rate for the 4th instar larvae was dose-dependent, and simultaneously the weight gain of 3rd instar larvae ceased within 48 hour after feeding of the cabbage leafdisk dipped into RH 5849 4.2 ppm solution. The systemic larvicidal effect of RH 5849 was compared at cabbage and tobacco whole plant test. The $LC_{50}$ values below 20 ppm(mg/kg soil) was lasted for 15 days in cabbage, 30 days in tobacco respectively.

• Journal of Sericultural and Entomological Science
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• v.35 no.1
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• pp.28-35
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• 1993

Treatment of juvenile hormone analogue(JHA) at the 5th instar larvae prolonged the duration of adult development one to one and half days as well as the elongation of feeding time with the increasing of larval body weight. Morphological observation and protein analysis in hemolymphs, integuements, alimentary canals, fat bodies and ovaries also revealed that the development of these tissues and organs for adultation are affected by the JHA treatment.

• Korean journal of applied entomology
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• v.37 no.1
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• pp.59-64
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• 1998

A juvenile hormone binding protein (JHBP) has been isolated from the whole body homogenate of Galleria rnellonella final instar larvae by gel filtration. The isolated protein is homogenous as judged by column chromatography and gel electrophoresis in the presence and absence of denaturing agent. The JHBP has a relative molecular weight of 32 k by denaturing gel electrophresis and 28 k by gel filtration. The protein exhibits a dissociation constant of 3.9 x M for JH 111.

• Korean journal of applied entomology
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• v.32 no.4
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• pp.450-456
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• 1993

We investigated effects of a topical treatment of methoprene(0.5-5.0$\mul$/egg), a juvenLle horm mane analogue, on embryo development in the gypsy moth, Lymantri$\alpha$ dispar. Methoprene lowered egg hatching rate, and also reduced the mean wet weights of hatched 1st instar larvae w with the most effect shown at the highest concentration. The differences in protein(p < 0.01) and carbohydrate(p < 0.05) contents between control and methoprene(5$\mul$/ egg) treatment g groups were observed during embryo development.

• The Korean Journal of Zoology
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• v.32 no.1
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• pp.1-8
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• 1989

Non-diapausing larvae and diapausing pupae of Pieris rapae L. were treated with 20-HE and JH, and the concentration of 20-HE and JH in body were also measured to determine mechanisms of diapause induction and termination. When early last instar larvae of non-diapausing stage were injected with 20-HE or JH-I, diapause was not induced in both cases. 20-HE concentration of pre-diapausing last instar larvae was very low, and 20-HE peak of non-diapausing two-day-old pupae was not present in diapausing pupae. There was no difference in concentration of JH-I between diapausing and non-diapausing stages. When early and late diapausing pupae were injected with 20-HE, JH-I, or JH-III. diapause was terminated by 0.1-0.5 $\mu$g of 20-HE, but not by JH-I, or JH-III. The above results indicate that diapause of Pieris rapae was induced by decrease of 20-HE concentration and also terminated by gradual accumulation of 20-HE during diapause process.

• The Korean Journal of Zoology
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• v.36 no.2
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• pp.238-244
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• 1993

We identified juvenile hormone binding protein (JHBP) from last instar larval hemollvnph of Hvphantria cunea using gel filtration and non-SDS PAGE. Two kinds of JHBP in hemollnnph were found at two peaks by gel filtration (Sephadex G-100) and also at Rm values of 0.13 and 0.57 by non-SDS PAGE. JHBP was partially purified using anion exchange chromatosraphv, preparative gel filteration, and preparative PAGE. Dextrin coated charcoal (DCC) binding assay was employed to monitor the location of JHBP in chromatographic profile during the purification process. Purity of JHBP was checked by silver staining of 1091 SDS-Polyacrvlamide.