Franklin & Marshall College

I am interested in the biochemical and molecular mechanisms by which marine organisms adapt to novel and extreme environments. This general area of research interest has led to three separate and ongoing research programs in my laboratory, which explore biochemical adaptation from different perspectives, using different techniques.

Adaptation of enzymes to temperature – Much of the work in my lab has focused on modifications in enzymes – how their structure is changed through mutations, and how those changes lead to optimization of function. I tend to study marine organisms that have recently adapted to changes in environmental temperature, because temperature can have a profound impact on protein structure and function. My students and I have explored structural changes in glycolytic enzymes from species as diverse as Antarctic notothenioid fishes, Galapagos marine iguanas, and temperate and sub-tropical gobies, to understand the link between protein structure and function in the face of environmental stress.

Acclimation via changes in osmolyte concentrations – In the past two years I have begun to examine the role of "counteracting osmolytes" in rapid acclimation to temperature change. Counteracting osmolytes are low-molecular-mass compounds that can stabilize protein structure during stress, and my students and I are pursuing a series of experiments to determine whether concentrations of these solutes increase in the cytosol as organisms experience severe temperature changes. We are using intertidal organisms, and especially mussels, for this work because they often are exposed to large temperature fluctuations from which they cannot escape.

Comparative proteomics of intertidal invertebrates – In collaboration with my colleague Lars Tomanek at California Polytechnic Institute, San Luis Obispo, my laboratory has begun to use proteomics techniques to examine changes in protein expression of intertidal invertebrates in response to environmental stress. By using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), digital gel analysis and mass spectrometry to identify proteins, we intend to identify those proteins whose expression profiles are most strongly affected by environmental stress. By determining the networks of proteins that are up- or down-regulated in response to stress, we hope to develop a more complete picture of how organisms protect the structure and function of macromolecules, and thus survive, in extreme environments.

I encourage students interested in undertaking independent research in my lab to contact me. Examples of research projects students recently have worked on in my lab at F&M include:

• Accumulation of counteracting osmolytes in the mussel Mytilus after heat shock
• Up-regulation of the DNA-repair enzyme photolyase in Daphnia in response to UV exposure
• Temperature adaptation in lactate dehydrogenase and citrate synthase of the Galapagos marine iguana
• Cold adaptation in lactate dehydrogenase and aldolase of Antarctic and Arctic fishes
• The role of enzyme function in the success of an invasive species of marine mussel, M. galloprovincialis