Ecdysteroids regulate the release and action of eclosion hormone in the tobacco hornworm, Manduca sexta (L.)

Truman, James W.; Rountree, Dorothy B.; Reiss, Shirley E.; Schwartz, Lawrence M.

doi:10.1016/0022-1910(83)90052-5

Cited by 143 publications

(70 citation statements)

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“…It then declines to a minimum value of 0.1 pg of 20-HE Eq/ml at 1 O-12 hr before ecdysis (Truman et al, 1983). At 24 hr before ecdysis, the ecdysteroids are present at about 0.4 kg 20-HE Eq/ ml (Truman et al, 1983). The EGPs cannot be phosphorylated in vitro at this time Truman, 1986, 1988).…”

Section: The Ability To Phosphorylate the Egps Requires 20-hementioning

confidence: 98%

“…Relationship of the ability to phosphorylate the EGPs to the decline in ecdysteroids Although the appearance of ecdysteroids at a molt is necessary for the acquisition of EH sensitivity, the steroids must then be removed from the system to allow EH to act (Truman et al, 1983). We investigated whether the appearance of the EGPs was also subject to this requirement.…”

Section: The Ability To Phosphorylate the Egps Requires 20-hementioning

confidence: 99%

“…This level is mimicked in vitro by between 0.05 and 0.01 wg/ml 20-HE. During the molt to the pupal stage, there is a critical period after which the application of exogenous 20-HE no longer prevents the appearance of EH sensitivity (Truman et al, 1983). Two sets of experiments were performed, one to determine the time at which 20-HE no longer prevented EH from triggering ecdysis behavior, and the second to determine the time at which 20-HE applications no longer prevented the subsequent ability to phosphorylate the EGPs.…”

Section: The Ability To Phosphorylate the Egps Requires 20-hementioning

confidence: 99%

“…In the tobacco hornworm, Manduca sexta, the insect only responds to EH during a narrow temporal window that occurs late in each molt (Reynolds et al, 1979;Truman et al, 1980). This transient appearance is regulated by the steroid molting hormone 20-hydroxyecdysone (20-HE; Truman et al, 1983).…”

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The EGPs: the eclosion hormone and cyclic GMP-regulated phosphoproteins. II. Regulation of appearance by the steroid hormone 20- hydroxyecdysone in Manduca sexta

Morton

Truman

1988

J. Neurosci.

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Two proteins (the EGPs) in the CNS of the tobacco hornworm Manduca sexta are phosphorylated by the action of the neuropeptide eclosion hormone (EH), which triggers ecdysis behavior (Morton and Truman, 1986, 1988). The onset of sensitivity to EH requires prior exposure to the steroid hormone 20-hydroxyecdysone (20-HE). A series of steroid removal and replacement experiments indicates that the EGPs are also regulated by 20-HE with a time course that is similar to that seen for the 20-HE regulation of behavioral sensitivity to EH. This suggests that the steroid regulation of EH sensitivity is due to the regulation of the EGPs. The appearance of the EGPs requires not only the presence of 20- HE, but also its subsequent removal. The appearance of the EGPs can be blocked in vivo and in vitro by maintaining artificially elevated levels of 20-HE, but only up to a particular time in development. The ending of this steroid-sensitive period occurs 4 hr before the normal appearance of the EGPs, consistent with the hypothesis that the EGPs are synthesized de novo in response to the removal of 20-HE.

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Section: The Ability To Phosphorylate the Egps Requires 20-hementioning

confidence: 98%

Section: The Ability To Phosphorylate the Egps Requires 20-hementioning

confidence: 99%

Section: The Ability To Phosphorylate the Egps Requires 20-hementioning

confidence: 99%

mentioning

confidence: 99%

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The EGPs: the eclosion hormone and cyclic GMP-regulated phosphoproteins. II. Regulation of appearance by the steroid hormone 20- hydroxyecdysone in Manduca sexta

Morton

Truman

1988

J. Neurosci.

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“…This system is of particular interest because the release of EH is tightly regulated by two factors: The declining titer of the steroid 20-hydroxyecdysone during the latter part of metamorphosis determines the day of EH secretion , while a circadian input determines the time of day when release occurs (Truman, 1972). These regulatory events can be experimentally manipulated in both intact and semi-intact animals (Schwartz and Truman, 1984;Truman et al, 1983), and the spontaneous activity of the cerebral neurosecretory system can be monitored electrophysiologically during the time of hormonal release Truman, 1984, 1986b).…”

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confidence: 99%

Identification of the cerebral neurosecretory cells that contain eclosion hormone in the moth Manduca sexta

Copenhaver

Truman

1986

J. Neurosci.

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Eclosion hormone (EH) is an insect neuropeptide that is released at the end of metamorphosis from the CNS and triggers the stereotyped motor program of adult emergence. Using three distinct experimental approaches, we have identified a discrete set of neurosecretory cells in the brain of the moth Manduca sexta that contains and releases EH. By isolating the neurosecretory somata and testing them with a sensitive behavioral bioassay, we identified a cluster of ipsilaterally projecting cells (Group Ia) that contain EH. Intracellular stimulation of individual cells within this group induced the release of bioactive EH into the hemolymph surrounding the neurohemal organs of the brain, whereas stimulation of cells in the other cerebral neurosecretory clusters did not. We also developed a polyclonal antiserum against purified EH that precipitated all bioactive material from samples containing the peptide. This antiserum selectively stained 5 of the Group Ia cells on either side of the brain, as well as their central and terminal processes. Preincubation of the serum with EH dramatically reduced its ability to bind the peptide subsequently. The combined application of these physiological and immunological techniques has led to the unequivocal identification of the EH neurons in the moth brain.

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Effect of the ecdysone agonists, RH-2485 and tebufenozide, on the southwestern corn borer,Diatraea grandiosella

Trisyono

Chippendale

1998

Pestic. Sci.

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:The e †ect of the ecdysone agonists RH-2485 (proposed name methoxyfenozide) and tebufenozide (RH-5992), was examined on eggs and larvae of the southwestern corn borer, Diatraea grandiosella Dyar. Both compounds exhibited a concentration-dependent ovicidal activity. More than 95% of eggs died when egg masses were dipped in solutions of 100 or 200 mg liter~1 of either compound in acetone ] distilled water (1 ] 1 by volume). Although some eggs treated with 1 or 10 mg liter~1 of the compounds hatched, the survival rate was low. Newly hatched larvae were fed for seven days on an artiÐcial diet containing RH-2485 or tebufenozide. The values were 0É049 mg kg~1 for RH-2485 LC 50 and 0É185 mg kg~1 for tebufenozide, showing that RH-2485 was about four times more active than was tebufenozide. Although increasing the time of exposure to either compound decreased the value signiÐcantly, the relative LC 50 potency of RH-2485 versus tebufenozide was not changed. Newly ecdysed 4th-instar larvae fed with diets containing 0É125, 0É25 or 0É5 mg kg~1 RH-2485 or tebufenozide ceased feeding approximately 8 h after exposure, indicating that larvae had prematurely entered a molting cycle. Larvae treated with RH-2485 ecdysed earlier and died more quickly than those treated with tebufenozide. Ingestion of sublethal concentrations of RH-2485 (0É005 and 0É01 mg kg~1) or tebufenozide (0É03 and 0É06 mg kg~1) retarded larval growth, and decreased pupal weight and adult emergence. Increasing exposure time to tebufenozide tended to increase the larval mortality, signiÐcantly retarded larval growth, and decreased the mean weights of male and female pupae and adult emergence. RH-2485 (0É125 and 0É25 mg kg~1) and tebufenozide (0É25 and 0É5 mg kg~1) were lethal to newly hatched larvae, even after diets containing these compounds were held for 20 days at 30¡C under long days (16 h light : 8 h dark). Our results suggest that Ðeld trials to assess the potential of RH-2485 and tebufenozide to control D. grandiosella are warranted.1998 SCI ( Pestic. Sci., 53, 177È185 (1998)

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Ecdysteroids regulate the release and action of eclosion hormone in the tobacco hornworm, Manduca sexta (L.)

Cited by 143 publications

References 14 publications

The EGPs: the eclosion hormone and cyclic GMP-regulated phosphoproteins. II. Regulation of appearance by the steroid hormone 20- hydroxyecdysone in Manduca sexta

The EGPs: the eclosion hormone and cyclic GMP-regulated phosphoproteins. II. Regulation of appearance by the steroid hormone 20- hydroxyecdysone in Manduca sexta

Identification of the cerebral neurosecretory cells that contain eclosion hormone in the moth Manduca sexta

Effect of the ecdysone agonists, RH-2485 and tebufenozide, on the southwestern corn borer,Diatraea grandiosella

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