• 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.

• 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.

• 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.

• The Korean Journal of Zoology
• /
• v.34 no.2
• /
• pp.196-202
• /
• 1991

Juvenile honnone binding protein (JHBP) was identified in the last instar larval hemolymph of Lymantria dispar using dextran coated charcoal (DCC) binding assay and gel filtration. The p1 value of JHBP was estimated to be 5.3. JHBP was partially pudfied by polyethylene glycol(PEG) precipitation, DEAE-cellulose ion-exchange chromatography and gel filtration, and was confirmed by DCC binding assay.

• Korean journal of applied entomology
• /
• v.40 no.2
• /
• pp.155-196
• /
• 2001

Basically insect hormones include ecdysteroids (molting hormone), juvenile hormones, and neurohormones comprising neuropeptides and biogenic amines. This article reviewed their chemical structures and biological functions. The active molting hormone is 20-hydroxyecdysone in most insects but makisterone A in some other insects including the honey bee and several phytophagous hemipterans. Most insects use JH III, but lepidopterans JH I and II. Dipterans also use a different JH, so-called JH $B_3$(JH III bisepoxide) and we still do not know the exact chemical structure of JH utilized in hemipterans. Some other insects use methyl farnesoate or hydroxylated JH III analogues as their juvenile hormone. Most diverse pictures can be found in neurohormones (NH), especially in neuropeptides, in terms of their number and structure. There are more than 200 neuropeptides (NP), classified into more than 30 families, which structures have been identified, and more of them are expected to be reported in the near future, partly due to rapid development in molecular biological techniques and in analytical techniques. More than half of them are involved in controlling activity of visceral muscles. But function (s) of many NPs are not clarified yet, even though their amino acid sequences have been identified. It is partly due to the fact that a single NP may have multiple functions. Another interesting point is their gene structure, having many number of independent, active peptides in one gene, apparently working for similar or totally different functions. NH also includes amines, such as octopamine, dopamine, serotonin, etc. From now on, investigation will be concentrated on identifying their function (s) and receptors, and on possibilities of their utilization as control agents against pest insects.

• The Korean Journal of Pesticide Science
• /
• v.13 no.2
• /
• pp.111-116
• /
• 2009

Juvenile hormone (JH) is an insect hormone mediating immature metamorphosis and adult reproduction. It also mediates immune responses to suppress hemocyte behavior, which is, however, activated by ecdysteroid. This study investigated an effect of a commercial pyriproxyfen (a JH agonist) formulation on a cellular immune response of the diamondback moth, Plutella xylostella, and analysed its mixture with Bacillus thuringiensis (Bt) in insecticidal potency. The commercial pyriproxyfen formulation significantly suppressed hemocyte-spreading behavior at low doses as did in pyriproxyfen technical grade. When the commercial pyriproxyfen formulation was mixed with Bt, Bt toxicity was significantly increased against P. xylostella larvae in laboratory. The mixture effect was then confirmed in field cultivating cabbage infested with P. xylostella larvae. The mixture showed a significantly enhanced mortality and reduced effective lethal time, compared to only Bt treatment.

• Journal of Sericultural and Entomological Science
• /
• v.39 no.2
• /
• pp.161-168
• /
• 1997

To clarify the effect of anti-juvenile hormone analogue (AJH) on the larval ecdysis by feeding at early stage of the 4th instar, the total amount of protein and activity of chitinolytic enzymes in the integument of Bombyx mori were analyzed, PAGE pattern of the protein was observed and the morphological changes of integument during molting period were also observed and the morphological changes of integument during molting period were also observed by means of TEM. The total amount of protein was greatly increased in premolting, then reached maximum level just before ecdysis, and rapidly decreased after the larval ecdysis in the control, while in the AJH treatment, increased 12 hr later than the control and its maximum was only 82.6% of the control. Two specific proteins, which were presumed as the protein originated from endocuticle, also appeared 12 hr later than the control and were maintained to 132 hr after AJH treatment from the aspects of the Native- and SDS-PAGE patterns, although those of the control disappeared instantly after ecdysis. Chitinase and $\beta$-N-acetylglucosaminidase activities were also suppressed and delayed by AJH treatment. Furthermore, it was observed that the apolysis took place 12 hr later than the control but new epicuticle was not formed at least until 132 hr after AJH treatment. From these results, it is suggested that the larval molting process of silkworm develops 12 hr later than the control but new epicuticle was not formed at least until 132 hr after AJH treatment. From these results, it is suggested that the larval molting process of silkworm develops 12 hr later than the control by AJH treatment but no further processing takes place just after apolysis.

• Korean journal of applied entomology
• /
• v.43 no.2
• /
• pp.143-153
• /
• 2004

Non-spinning syndrome of Bombyx mori has been serious issue in sericulture industry near Kyungbuk area. This study was focused on the analysis of the mechanism and on screening candidate chemicals inducing the anti-metamorphosis of the silkworms. Rearing temperatures or initial body weight of the final instar larvae did not affect a normal larval to pupal metamorphosis of B. mori. However, pyriproxyfen (a juvenile hormone (JH) agonist) induced follicle patency significantly even at its 10$\^$-8/ M concentration and inhibited metamorphosis of B. mori in both developmental time and dose dependent manners. Pyriproxyfen induced JH esterase (JHE) activity and downregulated expression of JH binding protein of 5. mori. These results suggests that pyriproxyfen induced JHE activity as a JH agonist and that the elevated JHE activity degraded endogenous JH and resulted in JHBP gene expression. Based on the fact that the JH agonist induced follicle patency and inhibited metamorphosis of B. mori, follicle patency bioassay suggested that three commercial pesticides including simazine, molinate or alachlor were proved to give potent JH agonistic effect on B. mori. Further direct exposure experiments to these candidates are required to determine the chemicals responsible for the non-spinning syndrome of 8. mori.

• Journal of Sericultural and Entomological Science
• /
• v.30 no.1
• /
• pp.25-32
• /
• 1988

In order to examine a physiological role of juvenile(JH) binding proteins in the hemolymph of the silkworm larva, Bombyx mori, [3H] JH I incubated hemolymph was separated by polyacrylamide gel electrophoresis in the fifth-instar larva and the activity of the binding protein was analyzed using charcoal binding assay. The results obtained were as follows; 1. The JH was bound by two protein fractions in the hemolymph of the fifth-instar larva; One was JH binding lipoprotein(JH-LP), the other was JH speific binding protein(JHBP). Their relative mobility values(Rm) were 0.3∼0.33 and 0.81∼0.84, respectively. There were no valid differences in those values from developmental stages of both male and female silkworms. 2. Total protein contents of the hemolymph were gradually increased during the fifth-instar larva, while at the prepupa decreased. The maximum ones were observed at the spinning period and the contents from female were much higher than those from the male. 3. JH binding activity per ml of the hemolymph was low in the early stage of the fifth-instar larva and its activity was maximized at the psinning period and at the prepupa slightly decreased. 4. There was a similar pattern between changes of the JH binding activity per ml of the hemolymph and of the total protein contents of the hemolymph. 5. The JH binding activity per mg of the hemolymph proteins was high in the early stage of the fifth-instar larva, while from the 6th day of the fifth-instar larva to the prepupa its activity showed the lowest levels.

• YAKHAK HOEJI
• /
• v.28 no.1
• /
• pp.1-10
• /
• 1984

A total synthesis of dehydrojuvabione which has high juvenile hormone activity, is described. The kinetic enloate of mesityl oxide is used as nucleophilic synthon for this synthesis. 1,4-Dioxaspiro [4,5] decan-8-carboxaldehyde was treated with kinetic enolate of mesityl oxide to give 8-(1'-hydroxy-5'-methyl-3'-oxo-4'-hexenyl)-1,4-dioxaspiro [4,5] decane. The latter compound was dehydrated. The resulted dienone was treated with lithium dimethylcuprate. After that, appropriate transformation was performed to give dehydrojuvabione.