SEMINAR: MBF602 STUDENT SEMINAR: TODAY @ 1PM---ANDREW KOUGH & ANDREW KEMPSELL

[Pam Harris <pharris@rsmas.miami.edu>]

 

MBF Student Seminar Series

Andrew Kough

Advisor: Dr. Claire Paris

“Lessons from the Larval Connectivity of

Caribbean Spiny Lobsters”

 The oceanic dispersal of the planktonic larvae that connect disjunct marine animal populations remains an enduring mystery, complicating the management of species that support valuable fisheries, especially since larvae recognize no international boundaries.  While revolutionary techniques such as stable isotopic tagging and parentage analysis have been proven effective at identifying small scale demographic connectivity patterns in reef fish, they are financially and logistically impractical on fishery relevant scales and unproven with invertebrates.  A commonly applied alternative technique is coupled-biophysical modeling.  This study focuses on the larval transport of the spiny lobster, Panulirus argus, as a representative species with a rich history of scientific inquiry, commercial worth exceeding 1B$USD, and cultural value firmly entrenched in many different countries.  The goal is to reveal the sources, sinks, and routes connecting the Caribbean metapopulation; synthesizing empirical data from laboratory studies, mail surveys, and previously published works to parameterize an individual based model of lobster larval connectivity.  Results were then evaluated using two independent sites, separated by over 500 miles, giving staunch support to the model’s performance - something never before achieved for spiny lobster or any other larvae at such large spatio-temporal scales. This sets a precedent for future explorations into wide-scale larval dispersal, demonstrating a successful union of empirical research and probabilistic modeling.

 

Andrew Kempsell
Advisor: Dr. Lynne Fieber
“Slugs ‘n’ Drugs: a pharmacological approach to distinguish D-Asp and L-Glu currents in Aplysia nerve cells.”

 

D-Aspartate (D-Asp) may be a novel neurotransmitter in the Aplysia nervous system. Previous studies have led to the proposal that D-Asp is an alternate agonist at ionotropic glutamate (L-Glu) receptor-channels (L-Glu receptors), specifically at N-methyl-D-Aspartate (NMDA) receptors, which are calcium channels with a role in both vertebrate and invertebrate learning and memory. Pharmacological differences were documented between D-Asp- and L-Glu-activated currents in whole cell voltage clamp studies in buccal S cluster neurons. Kynurenate, a general L-Glu receptor antagonist, blocked D-Asp whole cell current amplitude significantly by 27±19%. In the same cells, kynurenate blocked a significantly greater proportion (65±13%) of L-Glu-elicited currents, suggesting that the two agonists bind, in part, at different sites. PPDA, a subunit-specific NMDA receptor blocker, significantly reduced D-Asp and L-Glu currents by 46±22% and 46±11%, respectively, suggesting that ~46% binding of D-Asp and L-Glu is pharmacologically similar and might represent an NMDA-like receptor activated by these agonists. APV, a known NMDA receptor antagonist in vertebrates, blocked a small but significant percentage of D-Asp currents, but did not block L-Glu currents. Together, these findings suggest that D-Asp and L-Glu receptors share some binding sites but that there may be a unique D-Asp receptor not distinguishable with pharmacological tools.

Friday, November 18, 2011

1:00pm

RSMAS campus, S/A 103

Pamela Harris
Administrative Assistant
Marine Biology and Fisheries
Rosenstiel School of Marine and Atmospheric Science
University of Miami
4600 Rickenbacker Causeway/SLAB-118
Miami, FL 33149
(305) 421-4176
fax - (305) 421-4600
pharris@rsmas.miami.edu
http://www.rsmas.miami.edu/academics/divisions/marine-biology-fisheries/