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Derby, Charles

Regents Professor
Office: 992 Petit Science Center
Phone: (404) 413-5393
Email: cderby@gsu.edu

Biographical Information:

Ph.D. Boston Universty 1982
Postdoctoral Training: University of Florida
Joint appointment in the Department of Biology
Associate Dean for Natural & Compuational Sciences

Associate Editor of The Biological Bulletin

Research Description:

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.

Grant Support

NSF and NIH