Neurobiology of Molluscan Metamorphosis

My research has been focused on understanding how the developmental process of larval metamorphosis is controlled in marine  molluscs.  In particular, my coworkers and I have used the intertidal mud snail, Tritia obsoleta (also called Ilyanassa obsoleta or Nassarius obsoletus) as our model organism.  This animal lives on intertidal mudflats and is abundant along the coast of North Carolina.  You can see photographs of these snails, as well as examples of our research projects, in the slide show above.

My colleagues and I have studied the opposing actions of 2 major neurotransmitters, serotonin (5-hydroxytryptamine or 5-HT) and nitric oxide (NO), in the metamorphic pathway of this snail, but our most recent work focuses on the role of the inhibitory neurotransmitter, gamma aminobutyric acid (GABA).   In collaboration with Dr. Lawrence Cahoon at UNCW, we also learned that benthic diatoms can induce metamorphosis in T. obsoleta.   Results of various  research projects are discussed more fully under Research Projects.   Publication of recent results is still in progress.  All published papers are listed under Publications.

My interests in molluscan metamorphosis span a number of biological disciplines – from the ecological to the neurophysiological – and my research projects reflect the interdisciplinary nature of this aspect of developmental biology.   My students and I have used a variety of techniques, including pharmacological and injection experiments, immunocytochemistry, enzyme-linked immunoassays and electrophysiology.  Investigations that were conducted in collaboration with Dr. Mark Hens, here at UNCG, have allowed us to characterize aspects of the developmental expression of nitric oxide synthase (NOS), the enzyme that produces NO.  We have used several molecular methods to demonstrate that NOS expression declines during metamorphosis, supporting our hypothesis that NO production must be turned off for metamorphosis to be initiated.

My overarching goal has been to further our understanding of how the larval nervous system initiates and coordinates the irreversible events of metamorphosis.   Our projects have also allowed me to maintain my interests in the evolution of invertebrate nervous systems and developmental processes.