Biology Spring 2014

3 February: 

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Lavinia Sheets, Ph.D.
Amelia Peabody Fellow, Eaton-Peabody Laboratory; Research Fellow, Harvard Medical School. "Ribbon Synapses in Sensory Hair Cells: How to Make Them (and How We Break Them)" 

Research Summary:  "Broadly, my research interests are the formation and maintenance of synaptic connections between sensory hair cells-the transducers of sound, motion, and spatial orientation-and the nerve fibers that carry sensory information to the brain. More specifically, I'm interested in the signaling pathways and intracellular processes that contribute to hair-cell synapse formation during development and that bring about hair-cell synaptopathy following sound overexposure. I investigate these questions using zebrafish as a model for human hearing and deafness. Additionally, I take advantage of the zebrafish's extensive regenerative capacity to investigate how zebrafish regenerate hair-cell innervating nerve fibers after they have been damaged or lost. I anticipate that uncovering the cellular mechanisms that mediate noise-induced synaptopathy and nerve fiber regeneration in zebrafish will lead to the development of therapies to protect or replace damaged hair-cell synaptic contacts in humans.” [Host: Josef Trapani]

24 February: 

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Amy Camp, Ph.D.
Assistant Professor of Biological Sciences, Mount Holyoke College
"A 'Feeding Tube' Model for Bacterial Cell-Cell Communication"

 Research Summary: Upon nutrient starvation, the bacterium Bacillus subtilis transforms itself into a metabolically dormant spore.  This primitive developmental process involves two sister cells, only one of which becomes a spore.  The Camp Lab eavesdrops on these two developing cells to discover the elegant and unexpected ways that they communicate and control gene expression. [Host: Alexandra Purdy]

3 March: 

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Alexandre de Lencastre, Ph.D.
Assistant Professor of Biology, Quinnipiac University
"Small Agents of Long Life:  RNAs that Modulate Longevity and Stress Resistance"

Research Summary: Although hundreds of miRNAs have been identified in higher eukaryotes, the function of the vast majority of these remains a mystery. To uncover novel functions of miRNAs, we surveyed the expression of small RNAs in C. elegans during adulthood and characterized their function. We uncovered novel miRNAs and piRNAs that affect lifespan and stress resistance in C. elegans. We show that these novel RNAs are differentially regulated in aging animals and function through the DNA damage response and insulin signaling pathways. In addition, some aging-associated miRNAs interact with genes involved in dietary restriction-induced lifespan extension in C. elegans. The targets of these aging-associated RNAs reside in signaling pathways that are conserved from yeast to humans, suggesting that miRNAs and other small RNAs may play important roles in stress response and aging of more complex organisms.[Host: Yan Qi]

10 March: 

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Leslie Curren '05, Ph.D.
Fixed-term Faculty, Department of Biological Sciences, University of New Hampshire.
"Frenemies: Cooperation and Competition Among Male Spotted Hyenas”

 Research Summary: One way we can examine the bounds of Darwin’s theory of sexual selection is by studying species that appear to violate the traditional “rules.” Spotted hyenas thus present a unique opportunity to test predictions of sexual selection theory because they are partially sex role-reversed: females provide all parental care, but are also socially dominant to males. This partial role-reversal changes the selective pressures acting on males in comparison with other mammals. Here, Dr. Curren investigates one possible mechanism of intrasexual male competition, endurance rivalry.  She then explores the evolutionary forces that may favor male-male cooperation in this species. [Host: Ethan Clotfelter]

24 March: 

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Nancy Hollingsworth, Ph.D. 
Professor, Department of Biochemistry and Cell Biology, Stony Brook University
"Phosphorylation and the Regulation of Recombination in Budding Yeast Meiosis"

Research Summary: The Hollingsworth lab studies the roles that two kinases, the meiosis-specific Mek1 and the essential kinase, Cdc7-Dbf4, play in meiosis.  They have recently applied a biochemical approach to generate an unbiased list of potential substrates for these kinases in meiosis.  On-going research in the lab aims to determine the biological significance of the phosphorylation of various proteins by these kinases and the mechanisms by which these post-translational modifications regulate meiotic chromosome behavior. [Host: Caroline Goutte]

31 March: 

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Gary Ruvkun, Ph.D. 
Professor, Department of Genetics, Harvard Medical School
"C. Elegans Surveillance of Conserved Cellular Components to Detect and Defend Pathogen Attacks, Real or Imagined”

Research Summary: Dr. Ruvkun’s research has explored two major themes:  regulation by microRNA genes and other tiny RNAs, and control of longevity and metabolism by insulin and other endocrine pathways. Dr. Ruvkun’s lab has also used full genome RNAi libraries to explore the complete set of genes that regulate aging and metabolism. Many of the gene inactivations that cause increased survival encode the core conserved elements of cells that are targeted by antibiotics produced by fungi and microbes.  These core genetic pathways may be surveilled for toxin and virulence factor inhibition so that a decrement in function is interpreted as a microbial attack. The immune surveillance endocrine states that are normally induced by poisons or genetic variation in these surveillance pathways may underlie a variety of autoimmune and other diseases. [Host: Yan Qi]

7 April: 

Pamela Diggle, Ph.D.
Professor and Associate Department Head, Department of Ecology and Evolutionary Biology, University of Connecticut
“'A Great & Curious Blunder in Dame Nature:' Evo-devo and Darwin’s Exclamation"

 Research Summary: “My research concerns the evolution of morphological diversity among plants with particular emphasis on understanding how features of development shape the dynamics of evolutionary change.  My approaches range from analyses of developmental responses of individuals to contrasting environmental conditions, to understanding how development has evolved over time in groups of closely related plants, to understanding differences across all of flowering plants.  I examine development at the level of gene expression, the features of cells and tissues, and the features of whole plants as they unfold over an individual’s lifetime.“[Host: Rachel Levin]

14 April: 

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Vu Nguyen
Graduate Student, Department of Molecular and Cellular Biology, Harvard University
"Structural Insight into the Assembly and Conformational Dynamics of the ATP-Dependent Chromatin-Remodeling Complex SWR1"

Research Summary: The ATP-dependent chromatin remodeling complex SWR1 belongs to a diverse family of molecular motors that mobilize nucleosomes across the chromatin.  Using electron microscopy, Nguyen and colleagues have dissected the sophisticated assembly of this complex.  The 3D EM structure of SWR1 shows that it employs a heterohexameric ring of AAA+ proteins as a docking platform for structurally discrete functional modules.  He also observed a significant conformational change in SWR1 as a result of binding to a nucleosome.  His work provides an important structural foundation for future investigation of conformational dynamics in this unique remodeling machine. [Host: Yan Qi]

21 April: 

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Amanda Gibson '08
Ph.D. Candidate, Evolution, Ecology and Behavior Program, Indiana University
"A Phylogenetic Test of the Red Queen Hypothesis: Outcrossing and Parasitism in the Nematode Phylum”

Research Summary: The Red Queen Hypothesis argues that the eukaryotic preference for sexual reproduction all comes down to parasitism. It proposes that antagonism between hosts and parasites selects for: 1. Rare host genotype that can escape their rapidly adapting parasites, and 2. Rare parasite genotypes that can keep up with these escaping hosts. Outcrossing can generate a diversity of these rare genotypes and should thus be favored, while cloning or selfing tends to propagate static, common lineages that fail to rapidly adapt. Broadly, Gibson’s dissertation work tests basic predictions of the Red Queen. She uses a diversity of approaches, from field work in natural populations to experimental evolution in the lab. Here, she’ll focus on the Nematode phylum, where she uses phylogenetic comparative methods to determine if sexual outcrossing is more strongly favored in lineages of parasitic nematodes relative to free-living lineages. [Host: Michael Hood]

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Last Updated:
17 April 2014 TLR