Associate Professor
E-Mail: smoffett@wsu.edu
Phone: (509) 335-3290
We are studying function and control of the mosquito gut in larvae,
pupae and adults of Aedes aegypti, the yellow fever mosquito.
Ionic transport in the aquatic larvae produces an extreme alkalinization
(above pH 10) which serves the dual purpose of eliminating many
pathogens and releasing nutrients bound to tannins. The transport
also regulates ionic and osmotic movement across the gut and the
exchange of nutrients and wastes. The focus on the basic biology
of this species may allow control of a disease vector in a manner that
is environmentally safe.
The mosquito gut is modified along its length, and gut processes in
the different regions, including transport and motility, are regulated
by neurotransmitters such as serotonin and a large number of peptide
hormones. We study this system by isolating the gut and monitoring
the voltage in specific regions of the tubular epithelium while exposing
the blood and lumen sides to salines containing transmitters, peptides
and blockers of known transport systems. Transepithelical
recordings are combined with intracellular penetrations used for voltage
and ion specific measurements, and pH sensitive dyes reflect functional
changes that are videotaped. Electron microscopy is being used to
characterize the epithelial, regenerative and muscular cell types in the
gut at different life stages. Future directions will involve the
mapping and testing of receptors for the regulatory systems, with the
aim of generating new blockers specific to the vital transport systems.
This work represents a change from my previous studies of nervous system
regeneration in a snail that has a remarkable capacity for nervous
system repair. The operations on very small animals is a technical
parallel with the challenges of that work, and I have focused on the
process of metamorphosis as a parallel with regeneration, as stem cells
form the basis of new structures under the control of hormones in the
mosquitoes.
Biographical Information
Stacia B. Moffett, Associate Professor ofBiological Sciences, did
doctoral research on crab reflexes at the University of Miami, Coral
Gables, Florida. Postdoctoral research in Biomedical Engineering at Duke
University focused on effects of temperature on the nervous system of
the gastropod Aplysia.
Selected Publications
Moffett, S. 1997. Nervous System Regeneration in the Invertebrates.
Springer-Verlag, Zoophysiology Series Vol. 34.
Moffett, S. (2000) Regeneration as an Application of Gastropod Neural
Plasticity. In: Microscopical Research and Techniques,
Topical Issue: Gastropod Nervous Systems. 49:579-588.
Griffis,B.,
Moffett, S.B., Cooper, R.L. (2000). Muscle phenotype remains
unaltered after limb autotomy and unloading. J. Exp. Zool. 287
Bale, S.D., Howard, T.A., and
Moffett, S.B. (2001). Neuronal and
non-neuronal responses to nerve crush in a pulmonate snail, Melampus
bidentatus. Invert. Neurosci. 4: 105-117.
Onken, H.
Moffett, S.B., and Moffett D.F. (2004). The transepithelial
voltage of the isolated anterior stomach of mosquito larvae (Aedes
aegypti): pharmacological characterization of the serotonin-stimulated
cells. J. Exp. Biol. 207: 1779-1787.
Onken, H.,
S. B. Moffett, and D. F. Moffett (2004). The anterior stomach
of larval mosquitoes (
Aedes aegypti): effects of neuropeptides on
transepithelial ion transport and muscular motility. J. Exp. Biol.
207: 3731-3739.
Moffett, S.B. and Moffett, D.F. (2005). Comparison of immunoreactivity
to serotonin, FMRFamide and SCPb in the gut and visceral nervous system
of larvae, pupae and adults of the yellow fever mosquito,
Aedes aegypti.
Journal of Insect Science (online).
Clark, T.M., Hutchinson, M.J., Huegel, K.L.,
Moffett, S.B., Moffett,
D.F. (2005). Additional morphological and physiological heterogeneity
within the midgut of larval
Aedes aegypti (Diptera:Culicidae) revealed
by histology, electrophysiology, and effects of Bacillus thuringiensis
endotoxin. Tissue and Cell 37: 457-468.
Onken, H.,
Moffett, S. B. & Moffett, D. F. (2006). The isolated anterior
stomach of larval mosquitoes (
Aedes aegypti): voltage-clamp measurements
with a tubular epithelium. Comp. Biochem. Physiol. 143A:24-34.
