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
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
Stacia B. Moffett, Associate Professor of Biological 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.
1997. Nervous System Regeneration in the
Invertebrates. Springer-Verlag, Zoophysiology Series Vol. 34.
(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.
Bale, S.D., Howard, T.A., and Moffett, S.B.
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
of neuropeptides on transepithelial ion transport and muscular motility.
J. Exp. Biol. 207: 3731-3739.
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
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.