The Pacific Biomedical Research Center team studies the behavior and morphology of copepods, particularly how anatomy and structure relate to sensory perception and reaction. The copepods that have myelin surrounding their axons exhibit consistently and significantly faster response time to stimulus in laboratory tests. (Deeper dwelling copepods luminesce in response to danger and other copepods move away from stimuli, though more slowly.)
Team members include researchers Petra Lenz and Daniel Hartline, researcher and electron microscope supervisor Tina (Weatherby) Carvalho and graduate student April Davis. It was Davis who first noticed the characteristic onion-ring-like myelin circles around axons in copepod cross sections. Myelin-looking artifacts can occur as chemical fixation anomalies, so she and Carvalho confirmed the results by preparing samples using an ultra-rapid freezing technique.
Because myelin does not occur in less-evolved copepods, it appears to have developed separately from that of vertebrates and other invertebrates, notes Lenz. The researchers' work has implications for the study of evolution as well as the understanding of the biology of the oceans.
The copepod research is funded by a grant from the National Science Foundation Division of Integrative Biology and neuroscience. UH's electron microscope facility is supported by the National Institute of Health's Research Centers in Minority Institutions Program.