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

• Archives of Pharmacal Research
• /
• v.22 no.5
• /
• pp.502-506
• /
• 1999

Different 2-(8,12 dimethyl-5-oxa-7(E), 11-tridecadienyl)-alkyl phenyl ethers, their mono oxirane and thirane derivatives were synthesized and tested on Culex pipiens quinquefasciatus Say for their juvenile hormone activity.

• Proceedings of the Korean Society of Applied Entomolohy Conference
• /
• 2005.05a
• /
• pp.107-107
• /
• 2005

• Korean Journal of Environmental Biology
• /
• v.40 no.3
• /
• pp.255-266
• /
• 2022

In crustaceans, molting is regulated by interactions between ecdysteroid and juvenile hormone (JH) signaling pathway-related genes. Unlike the ecdysteroid signaling pathway, little information on the role of JH signaling pathway-related genes in molting is available in zooplanktonic crustaceans. In this study, three genes (juvenile hormone acid O-methyltransferase (JHAMT), methoprene-tolerant (Met), and juvenile hormone epoxide hydrolase (JHEH)) which are involved in the synthesis, receptor-binding, and degradation of JH were identified using sequence and phylogenetic analysis in the brackish water flea, Diaphanosoma celebensis. Transcriptional changes in these genes during the molting cycle in D. celebensis were analyzed. Sequence and phylogenetic analysis revealed that these putative proteins may be functionally conserved along with those of insects and other crustaceans. In addition, the expression of the three genes was correlated with the molting cycle of D. celebensis, indicating that these genes may be involved in the synthesis and degradation of JH, resulting in normal molting. This study will provide information for a better understanding of the role of JH signaling pathway-related genes during the molting process in Cladocera.

• Korean journal of applied entomology
• /
• v.61 no.1
• /
• pp.101-108
• /
• 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
• /
• v.36 no.2
• /
• pp.238-244
• /
• 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.

• The Korean Journal of Zoology
• /
• v.37 no.4
• /
• pp.495-503
• /
• 1994

Hemolymph SHBP (hJHBP) was partially purified from last instar larvae of Bombyx zori by gel filtration and their optimal reaction conditions of dextrin coated charcoal binding assay were determined. Dissociation constant (KD) of hJHBP for JH III was calculated to be 1.45 $\times$ 10-7 M at $4^{\circ}C.$ The molecular weight of hJHBP was estimated to be 30 kDa by gel filtration on a calibrated Sephadex G-100 column and 33 kDa by SDS-PAGE. These results indicate that hSHBP consists of a single polvpeptide chain. Isoelectric point of hJHBP was found to be pH 5.1 and 19 of the first 20 amino acid residues were determined from N-terminus of purified hJHBP.

• The Korean Journal of Zoology
• /
• v.37 no.1
• /
• pp.66-75
• /
• 1994

Juvenile hormone binding protein was identified in the hemolymph of fifth instar larvae and purified using column chromatography. Hemolymph was mixed with [3H] JH-III and electrophoresed on 691 NON-SDS gel, indicating that radioactivity peak appears at Rf value of 0.55. Gel filtration showed two radioactivity peaks equivalent to bound and free [3H]JH-III, respectively. JHBP was purified from hemolymph through gel filtration (Sephadex G-100), anion exchange chromatosraphv (DEAE Sepharose CL-6B), chromatofocusing chromatographv (PBE 94) and preparative electrophoresis.

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

• Journal of Sericultural and Entomological Science
• /
• v.34 no.1
• /
• pp.15-20
• /
• 1992

Effects of starvation, ligation, refeeding and methoprene treatment in the feeding phase of the fifth instar larvae of Bombyx mori on the regulation of juvenile hormone esterase(JHE) activity were investigated. Starvation and ligation contributed to the reduction of JHE activity, however, JHE levels in starved larvae were slightly higher than in legated larvae. Haemolymph JEH activity of starved larvae was increased by refeeding, and duration of increasing time of JHE activity after starvation was related to duration of starvation. When starved larvae were applied methoprene topically, JHE activity were not changed at day 0 and 1, but were increased by 1.3-1.4 times between day 2 and 5. When ligated larvae were applied methoprene topically, JHE activity was not changed at day 0, but were increased by 1.9-2.3 times between day 1 and 5. These results suggest that head factor, juvenile hormone(JH) and nutrient are major factors in the regulation of JHE in the feeding phase of the fifth instar larvae of Bombyx mori. Especially JHE might be regulated by the co-operative action of head factor and JH. However, head factor plays important role in the early stage, while JH plays important role thereafter.