Research Description:
Untitled Document
Dr. Derby has a joint appointment in the Neuroscience Institute as well as the Department of Biology
Chemosensory Neurobiology: Molecular, Cellular and Systems Analysis of Chemically-mediated
Behaviors of Crustaceans.
The research in my laboratory involves studies of the chemical senses -- smell
and taste. Our general objective is to understand the ways in which nervous
systems are organized to allow animals to detect, identify and respond to environmental
chemicals. We are particularly interested in natural, complex stimuli. We use
crustaceans (lobsters, crabs, crayfish) as model organisms. We are presently
employing a variety of techniques to answer questions involving different levels
of sensory systems; these include molecular, immunocytochemical, anatomical,
electrophysiological, and behavioral approaches. Projects include the following:
• How is odorant information processing in the olfactory organ and in
the brain? There exists a diversity of sensilla in the olfactory organ –
the antennule. Yet very few have been identified regarding their sensory function
and the projections of their neurons into the CNS. We are identifying these
chemosensilla, properties of their sensory neurons, and their central projections.
• Why do animals have a diversity of chemosensors and chemosensory pathways?
We are examining, through ablation and behavioral studies, the functional role
of the different neural pathways in olfactory discrimination, learning, and
orientation in odor plumes.
• How does the olfactory system change during development and growth?
The olfactory organ of lobsters is continually growing throughout the animal’s
life. We have demonstrated continuous turnover of olfactory neurons in the antennule,
showing that cells mature within several months after birth, and survive for
ca. 12 months before being turned over. We have also shown that this turnover
can be modulated by internal factors (molt stage) and external factors (damage
to the antennule). We are examining the dynamics to this turnover, using cell
and molecular techniques.
• How does cell proliferation and survival change with social experiences,
and what is the effect of this on chemosensory behavior and learning?
• What are the molecular controls of the neurogenesis and maturation of
olfactory neurons in the olfactory organ? We are identifying genes that control
this continuous growth of the antennule, including identifying proneural and
neurogenic genes and other transcription factors, and the role of serine proteases.
• How is the crustacean olfactory pathway organized to process pheromones?
We are examining processing of sex and social pheromones in blue crabs, crayfish,
and spiny lobsters, towards determining differences in neural pathways for pheromones
and food odors.
• What mechanisms do animals use to chemically defend themselves against
predators? We are finding that the sea hare Aplysia chemical defends itself
against predators (lobsters, sea anemones, fish) using a variety of mechanisms
including noxious chemicals (deterrence and cell damage) and phagomimicry (creating
a supernormal attractant of itself).
• Does the establishment of marine reserves in the Caribbean replenish
the supply of spiny lobsters? We are determining the age of spiny lobsters inside
and outside of marine reserves in the Dry Tortugas and Western Sambos, by quantifying
the levels of lipofuscin in their nervous system, to understand the population
structure in these areas.
Recent Publications:
McClintock, T.S., B.W. Ache, and C.D. Derby. 2006. Lobster olfactory genomics. Integrative and Comparative Biology (in press).
Johnson, P.M., C.E. Kicklighter, M. Schmidt, M. Kamio, H. Yang, D.
Elkin, W.C. Michel, P.C. Tai, and C.D. Derby. 2006. Packaging of
chemicals in the defensive secretory glands of the sea hare Aplysia californica. J. Exp. Biol. 209: 78-88.
Stepanyan, R, K. Day, J. Urban, D.H. Hardin, R.S. Shetty, C.D. Derby, B.W. Ache, and T.S. McClintock. 2006. Gene expression and specificity in the mature zone of the lobster olfactory organ. Physiological Genomics 25: 224-233
Caprio, J. and C.D. Derby. 2006. Aquatic animal models in the study of chemoreception. In Handbook of the Senses, Olfaction & Taste Vol. 2. Elsevier Press.
Schmidt, M., H. Chien, T. Tadesse, M.E. Johns, and C.D. Derby. 2006. Rosette-type tegumental glands associated with aesthetasc sensilla in the olfactory organ of the Caribbean spiny lobster, Panulirus argus. Cell Tissue Res. 325: 369-395.
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