Juvenile hormone acid methyltransferase activity in imaginal discs of <i>Manduca sexta</i> prepupae

Sparagana, Steven; Bhaskaran, G.; Barrera, Punnee

doi:10.1002/arch.940020207

Cited by 62 publications

(40 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also, it has been reported that it is the inactive JH acid that is released at the time of the prepupal peak of ecdysteroids. Only those cells containing the JH methyltransferase can convert the JH acid to the active JH methyl ester (Sparagana et al, 1985). If the IN cells do not contain this enzyme, they would be nonresponsive to the surge of JH acid that is released at this time.…”

Section: Discussionmentioning

confidence: 99%

Postembryonic neurogenesis in the CNS of the tobacco hornworm, Manduca sexta. II. Hormonal control of imaginal nest cell degeneration and differentiation during metamorphosis

Booker

Truman

1987

J. Neurosci.

View full text Add to dashboard Cite

The nervous system of an adult moth is comprised of retained larval neurons that are remodeled during metamorphosis and a set of new adult specific neurons. The new neurons arise from a stereotyped array of stem cells (neuroblasts) that divide during larval life to generate nests of up to 100 arrested postmitotic immature neurons, the imaginal nest (IN) cells. At the onset of metamorphosis, some of the IN cells die while the remainder differentiate into mature functional neurons. Metamorphosis in insects is regulated by 2 classes of hormones, the ecdysteroids and the juvenile hormones. The transition from larva to pupa requires the disappearance of juvenile hormones followed by 2 releases of ecdysteroids: a small “commitment peak” and a larger “prepupal peak.” Through a series of endocrine manipulations, we demonstrate that the death and differentiation observed among the abdominal IN cells at metamorphosis are both influenced by these hormonal cues. If the abdomen was isolated from the hormonal sources in the anterior half of the larva before the onset of metamorphosis, death and differentiation of the IN cells were prevented. Infusion of ecdysteroids into such abdomens, to mimic the prepupal peak, resulted in the IN cells showing the same fate as seen in control animals during the early phases of metamorphosis. The response of the IN cells to the small commitment peak of ecdysteroids was heterogeneous. Exposure to this small peak of steroids caused some cells to become committed to resume their development, making them resistant to juvenile hormone application.

show abstract

Section: Discussionmentioning

confidence: 99%

Postembryonic neurogenesis in the CNS of the tobacco hornworm, Manduca sexta. II. Hormonal control of imaginal nest cell degeneration and differentiation during metamorphosis

Booker

Truman

1987

J. Neurosci.

View full text Add to dashboard Cite

show abstract

“…In M. sexta, the JH titer in the hemolymph peaks during the prepupal period (35), when the CA produces only JHA. This JH peak is derived from the conversion of JHA to JH by JHAMT present in the imaginal discs (36) and possibly other tissues. Similarly, a significant increase of JH titer was observed in the hemolymph of B. mori during the prepupal period (14), when the CA does not synthesize JH (37), suggesting the presence of JHAMT activity in some peripheral tissues at this stage.…”

mentioning

confidence: 99%

Juvenile hormone acid methyltransferase: A key regulatory enzyme for insect metamorphosis

Shinoda

Itoyama

2003

Proc. Natl. Acad. Sci. U.S.A.

309

321

View full text Add to dashboard Cite

“…2;Law, 1981;Schooley and Baker, 1985;Cusson et al, 1991). Prepupal stages of the tobacco hornworm (Manduca sexta) and adult males of the silkworm (Hyalophora cecropia) also synthesize JH acids in the CA but release these compounds into the hemolymph, where they then undergo methylation in the imaginal discs or accessory sex glands, respectively (Peter et al, 1981;Sparagana et al, 1985).…”

mentioning

confidence: 99%

Biosynthetic Pathway of Insect Juvenile Hormone III in Cell Suspension Cultures of the Sedge Cyperus iria

et al. 2001

View full text Add to dashboard Cite

In most insect species, juvenile hormones regulate critical physiological processes such as metamorphosis and reproduction. In insects, these sesquiterpenoids are synthesized by retrocerebral endocrine organs, the corpora allata, via the classical mevalonate (MVA) pathway. One of these compounds, juvenile hormone III (JH III), has also been identified in the sedge Cyperus iria. In higher plants, biosynthesis of the sesquiterpenoid backbone may proceed through two distinct pathways: the MVA pathway or the 2C-methyl erythritol 4-phosphate pathway or through a combination of both pathways. Cell suspension cultures of C. iria were used to elucidate the biosynthetic pathway of JH III in the plant. Enzyme inhibition and labeling studies conclusively demonstrated that the biosynthesis of the sesquiterpenoid backbone of JH III proceeds via the MVA pathway. Inhibitor and precursor feeding studies also suggest that later steps of JH III biosynthesis in C. iria are similar to the insect pathway and that the final enzymatic reaction in JH III biosynthesis is catalyzed by a cytochrome P 450 monooxygenase.Juvenile hormones are a group of structurally related sesquiterpenoids that regulate critical physiological processes including metamorphosis and reproduction in most insect species (Gilbert et al., 1996). Juvenile hormone III (JH III), methyl-10R,11-epoxy-3,7,11-trimethyl-2E,6E-dodecadienoate, has also been identified in the sedge Cyperus iria (Toong et al., 1988).The presence of an insect hormone and its high levels in C. iria throughout development suggest that this compound may play a role in protection of the plant against insect herbivory (Toong et al., 1988; Bede et al., 1999a). However, there is no evidence that JH III functions as a feeding deterrent. Therefore, any antiherbivory activity would arise from its ability to interfere with insect development. In two laboratory studies, contact of insects with C. iria effectively disrupted development (Toong et al., 1988;Schwartz et al., 1998). These effects were attributed to the JH III content of the plant. However, conclusive evidence that this hormone protects C. iria against insect herbivory has not yet been demonstrated. We have proposed alternatively that JH III may function as an allelopathic agent in C. iria (Bede and Tobe, 2000). This plant species is an extremely invasive weed, responsible for economic losses in many important crops such as rice (Oryza sativa; Holm et al., 1977; Catling, 1992). Treatment of seeds with JH III delays lettuce (Lactuca sativa) seed germination and inhibits shoot growth of rice seedlings (Bede and Tobe, 2000). Therefore, it is possible that this compound confers an ecological advantage to C. iria by leaching from the roots, in which the highest levels are localized, into the immediate environment and affecting the germination and growth of neighboring competing plant species.Temporal and spatial changes in JH III levels are observed in C. iria throughout development (Bede et al., 1999a). JH III levels increased in the immature se...

show abstract

Juvenile hormone acid methyltransferase activity in imaginal discs of Manduca sexta prepupae

Cited by 62 publications

References 32 publications

Postembryonic neurogenesis in the CNS of the tobacco hornworm, Manduca sexta. II. Hormonal control of imaginal nest cell degeneration and differentiation during metamorphosis

Postembryonic neurogenesis in the CNS of the tobacco hornworm, Manduca sexta. II. Hormonal control of imaginal nest cell degeneration and differentiation during metamorphosis

Juvenile hormone acid methyltransferase: A key regulatory enzyme for insect metamorphosis

Biosynthetic Pathway of Insect Juvenile Hormone III in Cell Suspension Cultures of the Sedge Cyperus iria

Contact Info

Product

Resources

About