Upcoming Events

Ian Davison: "Neural Codes and Plasticity in the Olfactory System"

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April 2, 2015 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Odors carry a wealth of information about the world in both the animal kingdom and in humans. Mates, food, dominance, and predators are all evaluated using smell. However, it is not clear how the brain translates the chemical properties of odorants into patterns of neural activity that can be used to guide behavior.

In his lecture, Ian Davison explains the two main goals of his work on the olfactory system. The first is to understand how sensory perception emerges from neural computations in cortical circuits.  Natural odors comprise dozens to hundreds of chemical components, which the brain fuses of to form a single, unified sensory percept. Second, he examines how pheromone processing circuits are changed by social learning. In mice, mating drives rapid and robust pheromonal memory formation that alters the flow of sensory information to higher brain centers. To better understand the neural bases of sensory perception and plasticity, olfactory circuits are probed with a combination of physiology, imaging, and behavior.

Davison is assistant professor of biology at Boston University. He earned his Ph.D. in neurobiology at Simon Fraser University, Vancouver, Canada and was a postdoctoral research associate in the department of neurobiology, Duke University Medical Center, Durham, North Carolina.



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Paul Rawson: "Larval Responses to Salinity Stress in the Blue Mussel, Mytilus Edulis"

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April 9, 2015 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

The blue mussel, Mytilus edulis, is considered a foundational species that plays a key role in structuring intertidal and subtidal communities in the North Atlantic. Environmental stress, including stress from anthropogenic climate change, can have a profound impact on the
distribution and abundance of foundational species and thus on the resilience of intertidal community structure. Among other impacts, increases in greenhouse gases are expected to result in temperature extremes, ocean acidification and altered patterns of precipitation. With respect to the latter, the northeastern U.S. has already seen a large increase in very heavy precipitation events; such events can have a measurable impact on coastal salinity and productivity. The
phenotypic response of adult mussels to reduced salinity or hypoosmotic stress has been relatively well characterized. Blue mussels are osmoconformers and during osmotic stress they regulate intracellular free amino acid pools to remain isosmotic to the environment. Mussels, however, have a life history that includes a protracted period of larval development and the osmotic stress
response in larval stages has received much less attention. Larvae are
generally more sensitive to environmental stress and an increased frequency of stress events can lead to increases in larval mortality, ?recruitment failure?, and declines in population stability. Research in our lab has investigated whether phenotypic changes, in particular changes in the intracellular concentration of free amino acids, are correlated with changes in gene expression. I will present results from some of our on-going work exploring whether the transcriptomic and phenotypic response to osmotic stress differs for larval and post-metamorphic mussels.





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Mark Patterson, Northeastern University "Perforate and imperforate body plans in scleractinian corals: implications for coping with environmental stress"

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April 16, 2015 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

The physical biology of invertebrates (sponges, cnidarians, squid), plants (macroalgae, sunflowers, seagrasses), and fishes is another area in which I am broadly interested. The allometry of metabolism is an area where I apply chemical engineering theory to lower aquatic invertebrates and algae. Contrary to the predictions of “universal scaling laws” that have appeared in the literature, e.g., the West, Brown, Enquist (WBE) theory, these taxa do not follow 3/4 power scaling of metabolic rate with body mass. Instead they exhibit a diversity of scaling exponents for which I have developed a predictive theory based on first principles from fluid transport and mass transfer. This “flow modulated allometry” model is now being tested in my laboratory and in the field using the NOAA underwater habitat Aquarius. Since 1984, I have used saturation underwater habitats to conduct research in situ on corals and their allies. Recent work using Aquarius has examined how reef corals respond to water motion during bleaching episodes by altering their photobiology and expression of stress proteins. Our lab has recently developed a predictive electrical network model of the gastrovascular system of corals of the two types of coral bauplan, perforate (where an extensive plumbing connects the polyps) and imperforate (where polyps are not connected directly). This model will help us understand how corals respond to environmental stress including that posed by global warming and ocean acidification.

 

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Ron Peck, Colby College

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April 23, 2015 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Research Interests: Physiology and molecular biology of microbes in extreme environments; novel mechanisms of regulation in biochemical pathways

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Brad Davidson, Swarthmore College "Mitotic tuning: cell division modulates inductive signals during early heart development"

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April 30, 2015 4:00 PM  – 5:00 PM
Druckenmiller Hall, Room 020

Currently, our research is focused on revealing the precise function of FGF in early heart development. We have demonstrated that FGF signaling causes a group of 4 founder cells to undergo an asymmetric division. The smaller daughters of this division respond to continued FGF signaling by activating heart genes and migrating towards the site of future heart formation while the larger daughter form tail muscle.
Through transgenic manipulations, we can disrupt FGF signaling specifically in these four cells, blocking heart development. Conversely, we can activate downstream factors and cause the entire group of cells to migrate and form extra heart tissue (above image). We are also able to isolate Ciona heart cells and examine lineage-specific gene expression. This analysis employs micro-arrays designed to probe all predicted coding regions in the Ciona genome. Through these techniques we have identified an extensive set of heart genes up-regulated by FGF. Future studies will focus on determining the role of these FGF target genes in heart development as well as identifying the precise transcriptional mechanisms by which FGF and downstream factors co-ordinate heart gene expression.

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