Juvenile hormone III

Retinoic Acid Receptor. Most of the biological effects of retinoids are mediated through the retinoic acid receptor (RAR) and the retinoid X receptor (RXR). Both all-/ran.s-retinoic acid and 9-d.v-rctinoic acid serve as agonists of RAR, while only 9-d.v-rctinoic acid functions as an agonist of RXR. The functional RAR exists as a heterodimer with RXR, while functional RXR exists as a homodimer. Methoprene is a juvenile hormone III analogue that mimics the activity of this insect hormone. 

Figure 1.1 The three major types of hormones that regulate pheromone production in insects. A Juvenile Hormone III (C16 JH), B 20-Hydroxyecdysone and C PBANs from the corn earworm, Helicoverpa zea (Raina et al., 1989), the silkworm moth Bombyx mori (Kitamura et al., 1989) and the gypsy moth, Lymantira dispar (Master et al., 1994). The minimum sequence (pentapeptide) required for activity is indicated.

Figure 6.10 De novo biosynthesis of isoprenoid pheromone components by bark and ambrosia beetles through the mevalonate biosynthetic pathway. The end products are hemiterpenoid and monoterpenoid pheromone products common throughout the Scolytidae and Platypodidae (Figure 6.9A). The biosynthesis is regulated by juvenile hormone III (JH III), which is a sesquiterpenoid product of the same pathway. The stereochemistry of JH III is indicated as described in Schooley and Baker (1985). Although insects do not biosynthesize sterols de novo, they do produce a variety of derivatives of isopentenyl diphosphate, geranyl diphosphate, and farnesyl diphosphate. Figure adapted from Seybold and Tittiger (2003).

Jeffrey pine beetle, Dendroctonus jeffreyi Hopkins, which had been previously treated with juvenile hormone III (JH III, 2.2 pg/beetle in acetone) and then placed in an aeration tube for 25 to 30 h. Ips paraconfusus and I. pini were each injected with 0.2 pCi of sodium [1-14C]acetate prior to placement in cut pine logs and volatile collection, while D. jeffreyi were each injected with 3.8 (male) and 3.7 (female) pCi of sodium [1-14C]acetate 6.4 (male) and 10.7 (female) h after JH application. (G) The role of the mevalonate pathway in frontalin biosynthesis is supported by the incorporation of radiolabel from [2-14C]mevalonolactone into frontalin by male D. jeffreyi (2.2 pg JH 11 l/beetle in acetone, 10 h incubation and volatile collection, 1.1 pCi of [2 14C] mevalonolactone injected, 20 h volatile collection). Figures adapted from Seybold et al. (1995b) and Barkawi (2002). 

Lengyel, F., Westerlund, S. A. and Kaib, M. (2007). Juvenile hormone III influences task-specific cuticular hydrocarbon profile changes in the ant Myrmicaria eumenoides. 

Juvenile hormone III, an acyclic sesquiterpene epoxide, was also synthesized from (S)-25 by submitting the acetate of (S)-25 to the... 

Phvtoluvenolds. Wigglesworth (JL) demonstrated that a hormone secreted by the insect corpora allata was responsible for the control of differentiation in immature insects and reproduction in adult female insects. Williams (3) prepared an active extract of this hormone from adult male cecropia moths and called it "juvenile hormone". We were able to derive sufficient knowledge of the chemistry of the juvenile hormone from the study of the active cecropia extract to synthesize JH III Q). Seven years later its presence as a natural hormone in the tobacco hornworm was confirmed Ci). Three other analogous juvenile hormones (JH 0, I, II) have been found to occur only in lepidoptera (5, ., 2.) (Figure 1). Juvenile hormone III is the principal juvenile hormone of insects and has been demonstrated in all of the insect taxa investigated. 

Table II. The Effect on Larval Development and Uterine Gland Activity of feeding 20-hydroxyecdysone (20-OHE) on day 1 with or without Juvenile Hormone III on day 2, 4, and 6 of Second Pregnancy Cycle of G. m. morsitans...

Methoprene, a juvenile hormone analog, is structurally similar to insect juvenile hormones (Figure 4.11) such as juvenile hormone III. It is used for control of mosquitoes (floodwater mosquitoes, 2-4 instars), cigarette beetles, horn flies, fungus gnats (on mushroom), fleas, etc. The oral LD50 for methoprene in rats is >34,600 mg/kg. 

A similar set of reactions formed the basis of a short route to opticaUy active juvenile hormone III bisepoxide 222 [138] (Scheme 57). Since tertiary alcohols can be easily differentiated from primary and secondary hydroxyl functions, the cheaper and more reactive mesylate could be used in this case instead of a to-sylate. 

Pheromones.- Synthetic applications of phosphonate-based olefination to insect pheromones include the preparation of a juvenile hormone III... 

Scheme I. Mass spectroscopy fragmentation pattern of juvenile hormone III [23] (reprinted with kind permission from the American Chemical Society).

Proton Nuclear Magnetic Resonance Spectrum of Juvenile Hormone III... 

Juvenile hormones are lipophilic molecules and relatively insoluble in aqueous solutions. The solubility of JH I is approximately 3 x 10 2 mM in 0.2 M Tris-HCl buffer, pH 7.5 [32] changes in pH, buffer and ionic strength had no effect on solubility. The addition of proteins such as bovine serum albumin (BSA) and immunoglobulin G increases the solubility of JH I for example, in 5% BSA, a 1 mM solution of JH I can be made. Sonication also increases the solublity of the hormone by producing stable, finely dispersed micelles. Juvenile hormone III is more hydrophilic than JH I in 5 mM Tris-HCl, pH 8.3, the solubility of JH III is greater than 2 x 1CH mM [33]. However, its limited solubility must be recognized when preparing solutions. 

Fig. (2). Rates of juvenile hormone III (JH III) biosynthesis by the corpora aiiata (CA) of the penuitimnte and final instars of the cockroach, Diploptera punctata [43]. The rate of biosynthesis, which is closely correlated to haemolymph titers, was measured by an in vitro JH III radiochemical assay [45, 46, 47], Each point represents the mean of 3-12 determinations. Arrows indicate approximate times of ecdysis (reprinted with kind permission from Academic Press).

Fig. (3). Juvenile hormone III (JH III) release from the corpora allata (CA) of the oviparous cockroach, Supella longipalpa [48]. Juvenile hormone release was measured by the in vitro radiochemical assay [49, 50] and values represent the means of 5-12 determinations. Approximate times of mating and oviposition are indicated by arrows (reprinted with kind permission from Elsevier Scientific).

Fig. (5). Biosynthetic pathway of juvenile hormone III in the cockroach, Diploptera punctata [65, 71].

Plant secondary metabolites which mimic JH activity appear to be active on a narrow range of host species. What account(s) for this effect The majority of bioassays used last larval instars of P. apterus, O. fasciatus and pupae of T. molitor to test for activity of the juvenoids. Are these the most sensitive insects Six JHs have been identified to date different homologs have been isolated from specific insect orders. Juvenile hormone III appears to be ubiquitous [12, 13] and, in most species, is the only JH present. Juvenile hormone I and II are important in the regulation of metamorphosis and ovarian maturation in Lepidoptera [5] and the bis-epoxide appears to be the principle JH in higher Diptera [20]. Therefore, the nature of the JH in the test insect and the role that it plays in development must be considered in the selection of the bioassay a compound which mimics the action of JH in P. apterus (Hemiptera) is unlikely to be active in a Lepidopteran insect. 

Tablet. Chemical Data for Juvenile Hormone III, Methyl-10/ ,li-epoxy-3,7,II-trimetbyl 2/T,6/T-dodecadieneoate [21, 38, 180-183]...

Table 2. Mass Spectral Data for Juvenile Hormone III [23]...

Chemical shifts are reported as S values in ppm. Tetramethylsilane was the internal standard. Numbering of juvenile hormone III as illustrated in Appendix I, Table 3. 

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