Biology Spring 2012

SPRING 2012

January 30, 2012: Constance Jeffery, Ph.D., Associate Professor, Department of Biological Sciences, University of Illinois at Chicago. “The Multiple Lives of Moonlighting Proteins.”   The idea that one gene -> one protein -> one function has been found to be too simple as more and more proteins have been discovered to have multiple functions.  Dr. Jeffrey studies moonlighting proteins, a class of multifunctional proteins in which a single polypeptide chain has multiple biochemical functions that are not due to gene fusions, multiple RNA splice variants or multiple proteolytic fragments. As there is currently no straightforward method to identify which proteins have moonlighting functions, or for determining if a protein of interest is a moonlighting protein, Dr. Jeffrey is working to develop better methods to identify moonlighting proteins from their amino acid sequences or three-dimensional structures. Her lab is currently organizing information about the sequences, structures, functions and functional sites of moonlighting proteins with the goal of preparing a database of moonlighting proteins.  [Host: Program in Biochemistry and Biophysics (BCBP)]

February 6, 2012: Anne Leonard, Ph.D., Darwin Postdoctoral Fellow, Organismic and Evolutionary Biology, University of Massachusetts at Amherst.  “Signal Detection and the Function of Complex Floral Signals.”  Complex signals are one of the most widely-known but least understood phenomena in the natural world. For example, both courtship and anti-predator displays abound with conspicuous colors, elaborate sounds, and specialized scents. Likewise, plants attract pollinators with flowers that broadcast visual, olfactory, gustatory, tactile and thermal stimuli. Why should a signaler invest in a multimodal or multi-component signal when a simpler one might be cheaper to produce? How do receivers make efficient decisions if complexity requires extra time and energy to assess? Dr. Leonard’s research on bumble bees explores these questions from an evolutionary, ecological, and cognitive perspective. By exploring the costs and benefits of signal complexity in a plant-pollinator framework, she strives to define where the interests of sender and receiver coincide and where they are in conflict. [Host: Ethan Clotfelter]

February 13, 2012: Anna Savage '04, Ph.D. Molecular Evolution Postdoctoral Fellow, Smithsonian.  "Immunogenetic Adaptation to a Frog-Killing Fungus.”  Dr. Savage’s research investigates the role of host immunogenetics in contributing to dynamics of the emerging amphibian disease chytridiomycosis. She studies a Sonoran Desert endemic frog, Lithobates yavapaiensis, that shows both intra-specific and intra-population variation in susceptibility to chytridiomycosis. Using field surveys and laboratory experiments, she has found that allelic variation at a Major Histocompatibility Complex (MHC) class II gene significantly contributes to chytridiomycosis susceptibility within and among populations. Her results highlight the importance of maintaining genetic variability for the conservation of amphibian biodiversity in the face of a global disease epidemic. [Host: Rachel Levin]

March 5, 2012: James B. Ackman, Ph.D.  Postdoctoral Fellow, Department of Neurobiology, Yale University School of Medicine.  “Emergent Network Activity and the Development of Visual Circuits.”  Spontaneous electrical activity is a self-organized property of neuronal circuits that emerges in the absence of sensory input. During development, immature networks of neurons exhibit spontaneous patterned activity, even before the onset of sensory experience. Though it is generally thought that coordinated activity patterns could play an important role for directing activity-dependent refinement and Hebbian type plasticity in developing neurons, the nature and function of these spontaneous activities remains unclear. Dr. Ackman uses in vivo calcium imaging, together with electrophysiological and molecular genetic approaches in developing mice to understand how interactions within immature neuronal circuits leads to dynamic changes in connectivity which shapes the functional visual system.  [Host: Josef Trapani]

March 26, 2012: Amy Pederson, Ph.D., Advanced Fellow, Centre for Immunity, Infection and Evolution, University of Edinburgh.  “A Systems Approach to Host-Parasite Interactions in the Wild: From Simple Dynamics to Complex Interactions.”  In natural systems, hosts are usually co-infected by multiple parasites, and many parasites and pathogens can infect several host species. Dr. Pedersen’s research on host-parasite interactions aims to incorporate this realistic multiple host – multiple parasite/pathogen context. Specifically, her group: (i) evaluates the competitive interactions that occur between co-infecting parasites and the immune response to understand their impact on host health and to improve disease control strategies; and (ii) strives to elucidate the factors that drive host shifts and disease emergence in multi-host parasites. Her research approach integrates an array of methodologies to maximize the potential of ecological and evolutionary studies to address key questions about host- parasite interactions. [Host: Michael Hood]

April 2, 2012: John Stanton-Geddes, Ph.D., Postdoctoral Research Associate, Department of Plant Biology, University of Minnesota.  “Genes in Ecology, Ecology in Genes: Species Range Limits and Genomics of a Mutualism.”   Understanding the genetic basis for phenotypic variation and the consequences of this variation is a fundamental goal of evolutionary ecology research. In this seminar, Dr. Stanton-Geddes will discuss two separate projects that address this goal. First, he will present his doctoral research on the evolution of geographic range limits in a native annual legume. Second, he will discuss his current postdoctoral research to characterize the genetic basis of an ecologically and agronomically important mutualism – biotic nitrogen fixation by rhizobia in the roots of legumes. This is one of the first genome projects with whole genome sequence data for over 200 genotypes, greatly improving the resolution of our association mapping. Together, these research projects demonstrate how both organismal and genomic studies can further our understanding of ecology and evolution, and the many paths available to a wandering Amherst grad. [Host: Jill Miller]

April 9, 2012: Craig Albertson, Ph.D., Assistant Professor, Department of Biology, University of Massachusetts at Amherst.  "Toward the Origin of Craniofacial Diversity in Cichlid Fishes: Patterns, Processes and Mechanisms."  Dr. Albertson’s research interests lie at the intersection of genes, development and evolution.  His experimental model is the craniofacial skeleton in bony fishes.  Specifically, he is interested in integrating studies in a laboratory model (i.e., the zebrafish) and natural populations (i.e., cichlid fishes) to address questions related to the development and evolution of craniofacial and skeletal morphology. Methods of study include quantitative trait loci (QTL) mapping, population genomics, transcription profiling, experimental embryology, and quantitative shape analysis (geometric morphometrics). [Host: Ethan Clotfelter]

April 16, 2012: Stefanie Jeffrey, M.D., John and Marva Warnock Professor, Department of Surgery, Chief, Surgical Oncology Research, Stanford University School of Medicine.  "At the Crossroads of Engineering and Cancer Biology: Technology to Impact the Diagnosis and Treatment of Cancer.” Dr. Jeffrey is a cancer surgeon who develops new devices or applies new technologies to improve cancer care. Just after DNA microarrays were developed, she was part of the team that pioneered their application to cancer. She has also worked with NASA scientists to develop a multimodal instrument that analyzes biophysical and biochemical properties for tissue characterization. Most recently, she led a multidisciplinary team from Stanford’s Schools of Medicine, Engineering, and Genome Technology Center that invented an immunomagnetic enrichment device that extracts highly purified live rare cells from blood, such as circulating tumor cells. Her lab studies metastasizing cells and methods for personalizing cancer drug treatment through patient-derived in vitro and in vivo models and new microfluidic platform applications. [Host: Dominic Poccia, Program in Biochemistry and Biophysics (BCBP)]

April 23, 2012: Robert Sauer, Ph.D. Salvador E. Luria Professor of Biology, Massachusetts Institute of Technology.  "The Mechanism of ATP-Fueled Protein Unfolding by a AAA+ Proteolytic Machine.”  AAA+ enzymes convert the chemical energy of ATP binding and hydrolysis into conformational changes that disrupt the structures of macromolecular substrates. In ClpXP, a AAA+ protease, a hexameric ClpX ring catalyzes ATP-dependent protein unfolding and then translocates the unfolded substrate through a central axial pore and into the proteolytic chamber of ClpP, a double-ring compartmental peptidase. ClpX initially recognizes protein substrates by binding to exposed peptide sequences, such as the 11-residue ssrA tag. In this talk, Dr. Sauer will present recent crystallographic, biochemical, and single-molecule biophysical experiments that probe the detailed mechanism by which ClpXP unfolds and translocates substrates for degradation.  [Host: Program in Biochemistry and Biophysics (BCBP)]

Last updated:
24 February 2015 TLR