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Petit Institute Breakfast Club Seminar Series

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  • Item
    Decoding Memory in Health and Alzheimer’s Disease
    (Georgia Institute of Technology, 2019-04-09) Singer, Annabelle ; Parker H. Petit Institute for Bioengineering and Bioscience ; Georgia Institute of Technology. Wallace H. Coulter Department of Biomedical Engineering
    In this talk I will discuss how neural activity goes awry in Alzheimer’s disease, driving specific frequencies of neural activity recruits the brain’s immune system, and new methods to drive rhythmic activity non-invasively. Spatial navigation deficits are one of the earliest symptoms of AD and the hippocampus is one of the areas first affected by the disease. First, I will describe how neural codes underlying memory-based spatial decisions fail in animal models Alzheimer’s disease (AD). Using a virtual reality behavior paradigm to record and manipulate neural activity in transgenic mice, the primary animal model of AD, we found deficits in hippocampal neural activity early in the progression of the disease. These deficits occurred in the same patterns of activity that we have found inform memory-guided decisions in a spatial navigation task. Next, I will discuss the effects of driving these patterns of activity in AD model mice. We found that driving gamma activity, the activity lacking in AD mice, mobilized the immune system to remove pathogenic proteins. Specifically, driving gamma recruited the primary immune cells of the brain, microglia, to alter their morphology and increase engulfment of beta-amyloid. Finally, I will discuss new non-invasive methods we are developing to drive rhythmic neural activity non-invasively. Ultimately, these discoveries could lead to new therapies for Alzheimer’s disease by driving specific patterns of neural activity to impact the disease at the cognitive, cellular, and molecular levels.
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    Uncovering Metabolic Regulation and Dynamics
    (Georgia Institute of Technology, 2012-07-10) Styczynski, Mark P. ; Parker H. Petit Institute for Bioengineering and Bioscience ; Georgia Institute of Technology. School of Chemical and Biomolecular Engineering
    Understanding and controlling cellular metabolism (the process by which nutrients taken into a cell are turned into energy and the building blocks for more cells) is crucial to numerous applications, from enabling more efficient bioenergy production to unraveling the mechanisms of diseases like cancer. However, true understanding of (and control over) metabolism is hindered by a dearth of information available about the dynamics of metabolism and the molecular mechanisms that regulate those dynamics. A deeper understanding in these areas would enable much more efficient manipulation of existing metabolic networks to circumvent or exploit native metabolic regulation. In this seminar, we will discuss our work as we begin to unravel metabolic dynamics and regulation in two different (yet related) systems: yeast and cancer. Using mass spectrometry, we investigate the metabolic dynamics of cancer cells in response to environmental perturbations that we expect tumors to encounter in vivo. We also use complementary high-throughput analytical techniques to begin to enumerate the space of metabolite-protein interactions in the metabolic network of the yeast Saccharomyces cerevisiae.
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    Autonomous Mobile Robots for Personalized Caregiving
    (Georgia Institute of Technology, 2014-08-12) Kemp, Charles C. ; Parker H. Petit Institute for Bioengineering and Bioscience ; Biomedical Engineering (Joint GT/Emory Department)
    Mobile robots with autonomous capabilities have the potential to provide 24/7 personalized care, dramatically improving the quality of life of people with motor impairments. I will first provide an overview of opportunities for robots to provide beneficial physical assistance in the context of healthcare. I will then focus on my lab’s research to enable people with severe motor impairments to perform everyday tasks for themselves using mobile robots. In particular, I will focus on our work with Henry Evans, who has severe impairments due to a brain stem stroke. Through our research, Henry has been able to perform a number of tasks for himself for the first time in 10 years, such as pulling a blanket over himself, shaving himself, and operating mechanisms in his home. A key aspect of our work has been giving robots the ability to intelligently regulate the forces they apply while providing assistance.
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    The Two Unknowns of Nucleosomes: How They Are Formed and How They Are Removed
    (Georgia Institute of Technology, 2012-03-13) Kim, Harold D. ; Parker H. Petit Institute for Bioengineering and Bioscience ; Georgia Institute of Technology. School of Physics
    In eukaryotes, the genomic DNA is highly packaged inside the nucleus of a cell by forming beads-on-a string-like structure called nucleosomes. The propensity of a ~150-bp duplex DNA to form a nucleosome, termed the "nucleosome affinity", varies over a few orders of magnitude depending on the DNA sequence. Although nucleosome affinity is thought to be determined by DNA bending stiffness, the exact relationship between the two is not clear. Besides their role in DNA packaging, nucleosomes can repress gene expression by preventing transcription factors from accessing their DNA binding sites. Some nucleosomes, however, do not directly occlude transcription factor binding sites, and therefore their role in gene expression remains unknown. In the first part of this talk, I will explain how we measure looping kinetics and permanent curvature of various sequences of DNA using single-molecule FRET (fluorescence resonance energy transfer) and gel electrophoresis. I will then estimate nucleosome affinity of different sequences based on these measurements. In the second part, I will explain how we quantify gene expression pattern using fluorescence microscopy of yeast cells and demonstrate two examples where a nucleosome exhibits opposite effects on gene expression. Based on these results, I will present a model for nucleosome removal prior to transcription initiation.
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    Emergence of Genetic Complexity in Clonal Populations Evolving in the Lab: Implications for Cancer and Chronic Infectious Disease
    (Georgia Institute of Technology, 2018-10-09) Rosenzweig, Frank ; Parker H. Petit Institute for Bioengineering and Bioscience ; Georgia Institute of Technology. School of Biological Sciences
    A bacterial population that initially consists of a single clone can evolve into a population teeming with many, whether or not the surrounding environment is structured, and whether or not resource levels are constant or fluctuating. Emergence of genetic complexity, measured as functional information, has been variously attributed to balancing selection, clonal interference and/or clonal reinforcement arising from either antagonistic or synergistic interactions among evolving lineages. Using a combination of theory and experiment, we seek to define the boundary conditions under which one causal mechanism prevails over another. These investigations illuminate the process of adaptive evolution in other populations that originate as a single clone: those that give rise to cancer and those that bring about chronic infectious disease.
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    Regenerative Approaches to Treat Pediatric Maxillary Bone Deficiency
    (Georgia Institute of Technology, 2016-12-13) Goudy, Steven L. ; Parker H. Petit Institute for Bioengineering and Bioscience ; Children's Healthcare of Atlanta ; Emory University
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    Redrawing the Global Map of Drug Discovery Science: Hopes and Challenges in South Africa
    (Georgia Institute of Technology, 2017-10-10) Pollock, Anne ; Parker H. Petit Institute for Bioengineering and Bioscience ; Georgia Institute of Technology. School of Literature, Media, and Communication
    This talk draws on material from Anne Pollock's second book, forthcoming, provisionally titled Synthesizing Hope: Matter, Knowledge, and Place in South African Drug Discovery.
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    Towards an Evolutionary Synthetic Biology
    (Georgia Institute of Technology, 2009-11-10) Gaucher, Eric A. ; Parker H. Petit Institute for Bioengineering and Bioscience
    Evolution is the unifying theory behind biology, and has entered the mainstream of computational and molecular biology as a result of genomics. Nevertheless, evolutionary ideas today only barely influence the practice of molecular sciences. Innovation in many areas will be required before evolutionary analyses provide utility to biomedicine and biotechnology. Research in our laboratory attempts to enhance our understanding of evolutionary processes and structure-function relationships in the long-term, while also generating novel biomolecules having technological and therapeutic value in the short-term. If successful, these innovations will add utility to genome sequence data far beyond that found in comparative genomics. Using information extracted from molecular evolutionary analyses to guide the engineering of proteins is an innovative addition to existing methods. If evolution-guided engineering can deliver biomolecular properties not otherwise attainable with traditional engineering/directed evolution techniques, then this approach will have wide utility. The above activities form the foundation of our attempt to develop an evolutionary synthetic biology. We are energized by the prospect of joining evolutionary biology and synthetic biology. Synthetic biology appears to mean different things to different scientific disciplines. Surprisingly, however, biologists seem to have taken a backseat to chemists and engineers in the development of this field. It seems apparent that synthetic biology would stand to benefit if molecular evolution contributed to its progress.
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    Ant Rafts and Other Water Repellent Systems
    (Georgia Institute of Technology, 2012-04-10) Hu, David L. ; Parker H. Petit Institute for Bioengineering and Bioscience ; Georgia Institute of Technology. School of Mechanical Engineering
    We present a series of experiments demonstrating the water-repellent adaptations of a range of animals, from insects to mammals. These adaptations are necessary for survival in rain and other wet environments. During flash floods, fire ants weave hydrophobic rafts with their own bodies in order to keep their colonies dry. We discuss their method of self-assembly and present a model that predicts their construction rate. To survive raindrop impacts, flying insects take advantage of their low mass, which prevents drops from splashing on them. The resulting impact force on flying mosquitoes is 100-300 gravities, quite possibly the largest in the natural world. For such small insects, small size is advantageous in rain. If an animals is large, active mechanisms must be employed to shed water. Mammals of all sizes can shake off 70% of the water on their bodies in fractions of a second. We show that wet mammals shake at tuned frequencies to dry and present a scaling law relating animal size and frequencies required to dry. In this talk, the audience will learn the basics of modeling and experimentation with surface-tension phenomena.
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    Testing Thousands of Nanoparticles in Vivo
    (Georgia Institute of Technology, 2017-11-28) Dahlman, James E. ; Parker H. Petit Institute for Bioengineering and Bioscience ; Georgia Institute of Technology. Department of Biomedical Engineering