Juvenile Hormone Activity Research Articles

Synthesis of compounds with juvenile hormone activity. XX. Synthesis and biological activity of some juvenile hormone analogs lacking the alkyl substituents at C-7 or both at C-3 and at C-7.

Two groups of juvenile hormone analogs were synthesized. One lacks the alkyl substituent at C-7. The other possesses the alkyl substituents neither at C-3 nor at C-7. These analogs were almost inactive on Bombyx mori L. Some of them with the alkyl substituent at C-3, however, were active on Tenebrio molitor L. This indicates the very narrow sensitivity of Bombyx mori L. to juvenile hormone analogs.

Insect growth regulators with juvenile hormone activity.

The term insect growth regulator (IGR) was designed to describe a new class of bio-rational compounds. Through greater selectivity of action these compounds appear to fit the requirements for third generation pesticides, such as the absence of undesirable effects on man, wildlife, and the environment and compatibility with modern insect pest management principles. Although the majority of new com­ pounds in this class are the result of research on insect juvenile hormones, the general term IGR would also accommodate compounds with a different mode of action. The scope of this review, however, is restricted to those IGRs that produce only or primarily juvenile hormone-type responses. The nomenclature of the chemi­ cals and mixtures with JH activity has given rise to much confusion, and terms such as synthetic JH have occasionally been misused. The terms juvenoid, JH mimic, JH analog (JHA), etc all describe the general class of compounds fairly well. In this review we will use the term juvenile hormone (JH) for the natural hormones, IGR when compounds are used with an intention to control pests, and on occasion JHA for less defined situations. IGR, JH, and JHA may therefore occasionally be used for the same compound. Less than ten years have elapsed since the chemical structure of the first insect juvenile hormone (JH I) was elucidated in 1967. This was followed by the positive identification of two closely related structures (JH II and JH III, see Table I). Their presence in various combinations was subsequently proven in various insects, pri­ marily Lepidoptera (82). Schmialek in 1961 ( 180) was the first to elucidate the JH active isoprenoids farnesol and farnesal in excrement of Tenebrio molitor. The low specific activity of these structures made it unlikely, however, that these were actual hormones. It is remarkable that Bowers, Thompson & Uebel ( 18) synthesized the compound that later became known as JH III as early as 1 965, recognized its biological activity, and suggested that it had characteristics of a hormone. Industrial and federal involvement started a great flood of chemical analogs of the juvenile

Synthesis of compounds with juvenile hormone activity. XXI. Effect of the molecular chain length on biological activity of juvenile hormone analogs.

Twenty six juvenile hormone analogs with various molecular chain length were prepared and bioassayed using allatectomized 4th instar larvae of Bombyx mori L. Among methyl or ethyl esters, the chain length of 17 atoms is the optimal for the high juvenile hormone activity on the silkworm.

Role of juvenile hormone esterases and carrier proteins in insect development.

THE discovery of a binding protein, specific for juvenile hormone (JH)1 in the haemolymph of the tobacco hornworm, Manduca sexta, suggested that this protein carries JH molecules from the secretory organs (corpora allata) to the target sites. We report here that the binding protein provides the hormone total protection from degradative enzymes present in the haemolymph throughout early larval life2,3. Just before the start of pupal differentiation, however, a new esterase appears in the haemolymph which is able to hydrolyse the protein-bound hormone. We have also found that the binding protein at concentrations of 10−8 M strongly enhances the development-inhibiting action of JH on wing disk tissue in vitro. These properties, taken together, demonstrate a carrier role for the binding protein, and give new insights into the control of hormone levels in the haemolymph.

Time-dosage studies of juvenile hormone action on the development of Plodia interpunctella

The degree of inhibition of larval-pupal ecdysis of Indian meal moths, Plodia interpunctella, by juvenile hormone (JH) treatment depended upon the dosage of hormone and time of treatment. During the last larval instar, the timing aspect operated independently of dosage and had two essential components for effectiveness, (a) early initiation of exposure and (b) maintenance of exposure. The effects of JH treatments could be reversed by removing the insects from the JH diet. In vitro tests with wing disks indicated that JH reversibly inhibited disk development only during the early part of the last larval instar, a time when disks are insensitive to β-ecdysone. After disks acquire full sensitivity to β-ecdysone, they lose their ability to respond to JH.

Biochemical aspects of juvenile hormone action in insects.

Insects undergo profound morphological changes that take place long after the embryonic stage and are thus excellent models for the study of extrinsic control of genetic programs in higher organisms. In the process of metamorphosis, undifferentiated cells organized as imaginal disks develop into complex structures (legs, wings, antennae, etc.). The genetic program that dictates the ecdysone-induced differentiation and development of the imaginal discs is regulated and modulated by the juvenile hormone (JH). A high titer of juvenile hormone prevents differentiation and rapid growth of the disks. Prior to metamorphosis the hormone titer falls, and the low level then permits development to proceed. Thus, juvenile hormone exerts an inhibitory effect on the course of development during larval life.KeywordsJuvenile HormoneImaginal DiskFarnesyl PyrophosphateCorpus AllatumGeneral EsteraseThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Regulation of oogenesis, female specific protein production, and male and female reproductive gland development by juvenile hormone in the butterfly,Nymphalis antiopa

The role of the juvenile hormone (JH) in the regulation of oogenesis and the development of the male and female reproductive glands in the butterflyNymphalis antiopa was examined by means of classical endocrine methodology. The use of neck ligatures and allatectomies, with or without injections of compounds with high JH activity, demonstrated that JH is required for: 1) oogenesis and colleterial gland development in posteclosion adult females, and 2) tubular gland-ejaculatory duct and accessory gland enlargement in posteclosion adult males. Additionally, disc gel electrophoretic studies of hemolymph from males and females in several different physiological states, and of homogenates of mature oocytes indicated that JH is required for the normal presence in gravid female hemolymph of an apparent vitellogenin.

Teratogenic evaluation of terpenoid derivatives

Eight terpenoid derivatives with juvenile hormone activity were tested for teratogenicity. Three of the derivatives were teratogenic when administered to mice as a single intraperitoneal injection of 1 mg/gm on either day 9 or day 10 of pregnancy. However, intubation at 5 mg/gm of the two most teratogenic derivatives resulted in one of the derivatives marginally increasing the incidence of abnormal embryos above peanut oil-intubated controls; the other intubated derivative was without adverse affect. Of the remaining five compounds, two with high juvenile hormone activity were without teratogenic effect when injected at 1 mg/gm. Since teratogenic effects were observed only at a dose above likely exposure levels and by a route of administration not possible in the environment, support is provided for the potential use of terpenoid derivatives in the control of insect pests.

A comparison of the morphogenetic and sterilizing activities of juvenile hormone mimics on Aedes aegypti

At 25°C, adult female aedes aegypti are most sensitive to sterilization by juvenile hormone (JH) mimics when such chemicals are applied 32 to 36 hr after the blood meal (when the ovaries are at late stage III to early stage IV). Application of JH mimics during this period reduces egg fertility and female fecundity and induces the production of large numbers of visually abnormal eggs. As the most sensitive phase for sterilization with JH mimics is well before oviposition, and as many abnormal eggs are laid following JH mimic treatment, it is likely that in this species sterilization effects are induced by some action on the developing oöcyte rather than on embryonic development. The relative activities of several JH mimics in sterilizing adult female A. aegypti are very similar to their relative activities in inhibiting metamorphosis. Thus the sterilizing action of JH mimics is likely to be a true JH effect and can be used as a test for JH activity for A. aegypti.

A simple method to evaluate the juvenile hormone activity based on the color change of the larval marking in the silkworm, Bombyx mori

A simple method to evaluate the juvenile hormone activity based on the color change of the larval marking in the silkworm, Bombyx mori

Juvenile hormone and the adult development of Drosophila.

Topical application of Cecropia juvenile hormone (JH) blocked metamorphosis of the abdominal integument of pupating Drosophila larvae. JH treated adult flies retained more or less extensive areas of cuticle which could not be distinguished from pupal cuticle in whole mounts. Implantation into mature larvae of fragments of first instar larvae containing brains and ring glands provoked localized retention of patches of incompletely metamorphosed cuticle. An assay procedure for compounds with juvenile hormone activity was developed by defining the critical developmental stage and dose-response relationships. Twenty-two substances suspected of having juvenile hormone activity were assayed for their effect on Drosophila. These findings support the choice of Drosophila for resolving the genetic basis of juvenile hormone action.

Argas (Persicargas) arboreus: Juvenile hormone analog termination of diapause and oviposition control

The juvenile hormone analog acetaldehyde, 2-(2-ethoxyethoxy) ethyl p-(methylthio) phenyl acetal, topically applied in a concentration of 10 μg/5 μl acetone/female, terminated diapause and induced vitellogenesis and oviposition in fed female Argas (Persicargas) arboreus Kaiser, Hoogstraal, and Kohls (Argasidae). This is the first reported hormonal termination of diapause in argasid ticks. A full bloodmeal and mating were critical factors controlling oviposition in nondiapausing females, and may enhance juvenile hormone activity. Experiments suggest that tick bodies possess sites of hormonal activities similar to those in other arthropods.

Compounds Related to Juvenile Hormone: Activity of Selected Terpenoids on Tribolium castaneum and T. confusum

Nine compounds were evaluated for juvenile hormone activity against insecticide resistant and susceptible strains of the red flour beetle, Tribolium castaneum (Herbst), and a resistant strain of the confused flour beetle, T. confusum Jacquelin duVal. The candidate compounds were incorporated into the diet of the developing insects at a concentration of 5 ppm. The most effective compounds inhibiting development in T. castaneum were an aromatic terpenoid ether and a 14-carbon chain alkyl terpenoid ketone; development of T. confusum was not inhibited by any of the compounds. A high degree of morphological deformity in the developing adults was induced in both species by a 15-carbon chain alkyl terpenoid ketone.

The control of egg maturation by juvenile hormone in the tobacco hornworm moth, Manduca sexta.

1. In Manduca sexta females, follicles develop independently of the corpora allata until they reach a critical stage in late vitellogenesis. In the absence of juvenile hormone (JH), follicles then degenerate. When JH is present, the follicles continue development; they then become independent of JH for the final 12 hours of egg maturation. 2. Allatectomy of the pupa of Manduca sexta or the newly eclosed adult female prevents egg maturation as does extirpation of the brain from the pupa or decapitation of the adult. The ability to develop follicles beyond the vitellogenic phase is restored by injection of synthetic JH or JH mimics. 3. The brain activates the corpora allata close to the time of adult emergence. The glands secrete JH at a constant rate for 48 hours and then become less active in virgin, unfed moths. 4. A female specific protein, identified by SDS gel electrophoresis, is present in adult blood and egg homogenates. Allatectomy has no effect on the concentration of vitellogenin in the blood nor on its incorporation into immature follicles less than one mm long. 5. The action of JH in promoting egg maturation in Manduca sexta appears to be different from that in most other well-studied insect systems in that the hormone is not required for the synthesis and/or uptake of the female-specific yolk protein. Rather it is required for a critical step in development.

Juvenile hormone inhibits differentiation of olfactory sense organs during postembryonic development of cockroaches

The density of olfactory sense organs on the antenna of the cockroach, Leucophaea maderae, is relatively constant throughout larval development (average 400 sensilla/mm 2), but undergoes a substantial increase at the adult state (to about 620 sensilla/mm 2). Experimental manipulations of juvenile hormone (JH) activity result in either supernumerary larval instars (induced by unilaterla antennectomy or addition of exogenous JH), or premature adulthood (induced by allatectomy). The density of antennal sensilla remains at the larval level during the extra instars, but increases to the adult level or surpasses it at the terminal ecdysis following the induction of extra instars. Adultoids resulting from allatectomized sixth instars also have the high density of antennal olfactory sensilla characteristic of the normal adult. These data suggest that an interplay of surface area effects and an inhibitory action of JH controls the pattern of postembryonic development of antennal olfactory sensilla. Limited behavioural observations of the insects resulting from these experiments are consistent with the hypothesis that sex attractant-specific olfactory receptors appear only at the adult stage. However, electrophysiological data will be needed to confirm or negate this hypothesis.

Dependence of juvenile hormone activity on haemolymph factor in Tenebrio molitor pupae

Morphogenetic response of Tenebrio molitor pupae to juvenile hormone (JH) varies with age, it being low during the first 6 hr after pupal ecdysis and reaching a peak at about 18 hr after ecdysis. Parabiosis of 6-hr pupa to a 18-hr-old pupa causes a higher morphogenetic response in 6-hr pupa to JH. A similar increase in morphogenetic response was not noticeable when a 0·45 μm Millipore filter was placed between the parabiotic partners, suggesting that the factor(s) may be macromolecular. This view is further supported by the observation that the Millipore filter did not prevent transport of ecdysterone another agent that enhances morphogenetic response of pupae to JH.

Effect of ecdysterone on ethyl trimethyl dodecadienoate juvenile hormone action in Oncopeltus fasciatus

Ethyl trimethyl dodecadienoate exhibited a strong juvenile hormone action in large milkweed bug larvae ( Oncopeltus fasciatus) whereas ecdysterone caused minimal juvenilizing effects. Topically applied ethyl trimethyl dodecadienoate was not synergized by simultaneously injected ecdysterone.

Compounds related to juvenile hormone. Activity of arylterpenoid compounds in four insect species.

Twenty-four arylterpenoid compounds were tested for juvenile hormone activity against Tenebrio molitor L., Oncopeltus fasciatus (Dallas), Stomoxys calcitrans (L.), and Musca domestica L. Most compounds were more active against O. fasciatus. However, when the epoxide functional group in a few selected compounds was exchanged for an ether group, a change of species specificity occurred in favor of T. molitor .

ChemInform Abstract: SYNTHESIS AND BIOLOGICAL ACTIVITY OF ANALOGS OF THE CECROPIA JUVENILE HORMONE WITH DIFFERENT ALKYL SUBSTITUENTS AT C‐7 AND C‐11

AbstractIn zehn Reaktionsschritten werden aus den Ketonen (I) I6 neue Juvenilhormon‐ Analoga (XIV) als Stereoisomerengemische hergestellt.

Juvenile hormone activity of substituted aryl 3,7-dimethyl-6-octenyl ethers in the stable fly and house fly

Tests of substituted aryl 3,7-dimethyl-6-octenyl ethers and their epoxidized analogues produced a juvenile hormone (JH) mimic that was active against both the stable fly, Stomoxys calcitrans, and the house fly, Musca domestica. The criterion of activity in the JH bioassays was the formation of pupal-adult intermediates within the puparia.