Jeffrey Richards

The primary goal of my research program is to understand the adaptive significance of the mechanisms coordinating cellular responses to stress. Specifically, I am interested in the physiological, biochemical, and molecular mechanisms that act to balance energy supply and demand during short- and long-term exposure to environmental stress and the signal transduction pathways responsible for coordinating acclimation.
In organisms with the capacity to acclimate, exposure to an environmental stress induces a temporal cascade of events culminating in an enhanced ability to endure the newly imposed stress. This temporal cascade begins with the rapid and reversible modification of cellular proteins (e.g. phosphorylation & protein aggregation) followed by changes in gene expression (mRNA transcription and protein translation), both of which act to homeostatically optimize cellular pathways resulting in acclimation. To date, considerable research has focused on the impact of various environmental stressors on individual physiological or biochemical systems (e.g. effects of exercise on lactate production); however, little research has focused on the importance of a coordinated response to environmental stress across multiple pathways the signal transduction pathways involved in this response.

I currently use hypoxia (low oxygen), exercise, and salinity transfer as ecologically relevant challenges to induce bioenergetic stress in fish. Fish are an excellent model to examine bioenergetics and adaptation to environmental stress because they routinely encounter harsh environmental conditions (e.g. hypoxia) and posses the physiological, biochemical and molecular framework to deal with these perturbations. During exposure to environmental stress, fish must coordinate changes in energy demand with changes in energy supply. Several candidate signal transduction cascades (e.g. mitogen activated protein (MAP) kinase and 5’AMP protein kinase (AMP kinase) pathways) are known to modify the activity of various rate limiting enzymes and transcription factors and thus facilitate acclimation. However, the relationship between signal transduction pathway organization and the coordinated response to environmental stress has not been examined, especially in the context of acclimation or adaptation. Thus, my research program integrates mechanistic physiology, utilizing model organisms and their available tools (microarrays, proteomics, phospho-antibodies, and pharmacological tools), with comparative physiology to put the mechanism into an environmental, ecological, and evolutionary context.