REGULATION OF INSECT JUVENILE HORMONE BIOSYNTHESIS

Project: Research project

Project Details

Description

Juvenile hormone (JH) is a sesquiterpenoid produced in specialized
endocrine glands, the corpora allata (CA). JH controls metamorphosis and
reproduction in insects and this endocrine system can be exploited as a
target for agents active against insect pests of public health importance
(e.g. the JH analog medioprene). The long term objective of this
proposal is to gain a better understanding of the biochemical and
neuroendocrine regulation of JH synthesis in insects. This research will
facilitate the rational design of compounds that disrupt JH synthesis.
The present project will focus on the viviparous cockroach, Diploptera
punctata, an insect that produces a single JH homolog (JH III) at very
high rates in a well-defined physiological context. Several
allatostatins, peptides that inhibit JH synthesis, have been isolated
from the brain of D. punctata and sequenced over the last few years.
Work on the biochemistry of JH synthesis and its neuroendocrine control
in adult female D. punctata will be continued with the following specific
aims: 1/ To clone and sequence the allatostatin gene(s) from D. punctata. The
allatostatin gene(s) will be cloned from a brain cDNA library or a
genomic library using oligonucleotide screening, antibody screening or
PCR. The number and structure of the allatostatin gene(s) will explain
the basis of the diversity of allatostatic peptides and facilitate the
characterization of allatostatin-related peptides occurring naturally in
this species. 2/ To characterize the allatostatins gene product(s). The putative
peptide products of the allatostatin gene(s) will be compared to known
peptides and new peptides will be synthesized and tested for inhibitory
activity on the corpora allata. Isolation and purification of these new
peptides from brain extracts will be facilitated by an allatostatin
ELISA. 3/ To study the physiology of allatostatins. With the help of recently
developed ELISAs for allatostatins and chromatographic separation as
needed, the levels of allatostatins will be followed in adult females.
Particular attention will be devoted to the respective ratio of peptides
in the hemolymph, in different tissues and at different times during a
cycle of JH synthesis. Allatostatins will be tested in bioassays for
salivary gland secretion and hindgut myotropic activity to establish
whether they have a physiological function in peripheral tissues, as
suggested by immunolocalization studies. New bioassays may facilitate
future structure/activity studies on these peptides. 4/ To study the acquisition of allatostatin sensitivity by the CA in
vitro. The rapid increase in allatostatin sensitivity observed at the
end of vitellogenesis in vivo will be studied with an in vitro assay, and
the factor(s) responsible for this change will be characterized.
StatusFinished
Effective start/end date1/1/853/31/03

Funding

  • National Institutes of Health: $156,028.00
  • National Institutes of Health: $151,485.00

ASJC

  • Medicine(all)

Fingerprint Explore the research topics touched on by this project. These labels are generated based on the underlying awards/grants. Together they form a unique fingerprint.