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- nanoUtah Annual Conference
Monday, October 7th, 2013
University of Utah, Department of Chemistry
Abstract: Human telomeric DNA has tandem repeats of the sequence 5’-TTAGGG terminating with a 3’ single-stranded overhang of 100-200 bases. These guanine-rich DNA sequences can fold into tetra-stranded structures, known as G-quadruplexes. The precise fold of the G-quadruplex structure is dictated by the metal ions present, which we have studied through the use of the α-hemolysin ion channel. Being electrophoretically driven into the cis side of the α-hemolysin, the hybrid fold (K+) entered the vestibule leading to current blockages for the duration of the time the DNA resided in the vestibule. Due to the polymorphic nature of the hybrid folds, the recorded current signatures could be correlated to the major structural topologies that exist for this fold in solution (e.g., hybrid-1, hybrid-2, and triplex). The hybrid folds were not capable of traversing to the trans side of the nanopore, while the triplex could achieve translocation. Secondly, oxidative damage to the telomeric sequence is proposed to contribute to telomere shortening, dysfunction and cell aging. Locations of the oxidative damages have different effects on the G-quadruplex folding that produced significant changes in their nanopore behavior. Placement of the guanine oxidation product, 8-oxoguanosine (OG), in a top or bottom tetrad results in destabilization of that layer, whereas the presence of OG in a middle tetrad leads to complete unfolding of the G-quadruplex. These behaviors were determined by their translocation times, which correlated with the folding free energy.
Brief Bio: Dr. Cynthia J. Burrows is Distinguished Professor of Chemistry at the University of Utah and presently Chair of the Department of Chemistry. She was raised in St. Paul, Minnesota and Boulder, Colorado. Her early training was in physical organic chemistry with Prof. Stan Cristol at the University of Colorado (B. A. 1975) and Prof. Barry Carpenter at Cornell University (Ph.D., 1982), followed by a NSF-CNRS postdoctoral fellowship in the laboratory of Prof. Jean-Marie Lehn, Université Louis Pasteur, Strasbourg (1981-83). From 1983-1995, she held the positions of Assistant through Full Professor of Chemistry at the State University of New York at Stony Brook, before returning to the West to take a position at the University of Utah in Salt Lake City in 1995.
Prof. Burrows has been a member of numerous editorial boards and review panels; from 2001-2013, she served as Senior Editor of the Journal of Organic Chemistry. She is a past recipient of the Robert Parry Teaching Award and in 2011 of the University Distinguished Teaching Award; her research was recently recognized with the ACS Utah Award, ACS Cope Scholar Award, and the University of Utah’s Distinguished Creative and Scholarly Research Award. In 2009, she was inducted into the American Academy of Arts and Sciences, and in 2013 she was appointed the inaugural holder of the Thatcher Presidential Endowed Chair of Biological Chemistry.
Where: 4100B HSEB
Monday, October 28th, 2013
University of Utah
Abstract: Nucleic acids are exquisitely adept at molecular recognition and self-assembly, enabling them to direct nearly all of the processes that make life possible. These capabilities have been fine-tuned by billions of years of evolution, and more recently, have been harnessed in the laboratory to enable the use of DNA and RNA for applications that are completely unrelated to their canonical biological roles. In our lab, we utilize DNA aptamers as recognition elements for the development of new small-molecule detection assays. Specifically, interaction of an aptamer with its target is designed to direct assembly or disassembly of DNA or DNA-polymer conjugates, providing an output that can be observed visually or spectroscopically. Small molecule targets of interest include drugs, metabolites, and toxins.
Brief Bio: Jennifer Heemstra received her B.S. in Chemistry from the University of California, Irvine, in 2000. In 2005, she completed her Ph.D. with Prof. Jeffrey Moore at the University of Illinois, Urbana-Champaign, and after a brief stint in industry as a medicinal chemist, she moved to Harvard University to pursue postdoctoral research with Prof. David Liu. In 2010, Jennifer began her independent career in the Department of Chemistry at the University of Utah. Her research group is focused on harnessing the molecular recognition and self-assembly properties of nucleic acids for applications in biosensing and bioimaging.
Where: 4100B HSEB
Monday, November 4th, 2013
University of Utah
“The Physics, Chemistry, and Topology Behind Particle Transport and Retention in Aqueous Saturated Porous Media: How Natural Water Filtration May Relate to Drug Delivery”
Abstract: Whereas drug delivery science/engineering concerns targeted delivery of particles to (for example) organs or tumors, and therefore involves maintaining particle stability and minimizing losses to non-target surfaces, many of the same types of concerns apply to hydrogeologic processes. For example, similar concerns govern bioaugmentation, the targeted delivery of bacteria with novel metabolic properties to degrade xenobiotic contaminants in the subsurface, as well as improved prediction of set-back distances of drinking water wells from septic systems. In all of these contexts, there is a need to understand particle transport and retention at a sufficiently mechanistic level to optimize design of the process, e.g. optimal sizes, concentrations, surface moieties, etc. relative to the media being traversed. The coupling of micro-scale direct observations to “whole organism” observations and numerical simulations has transformed understanding of particle transport and retention in porous media, and these coupled approaches in the natural water filtration context has potential application in the drug delivery context. The talk will review the unique physicochemical attributes of particles relative to solutes that govern particle interactions with surfaces and the near-surface flow field, and will suggest means to capitalize on these attributes in targeted delivery.
Brief Bio: Dr. Johnson’s research focuses on the physics and chemistry of natural water treatment by filtration in granular aquifers (groundwater). His research also examines the fate and transport of trace elements, and the partitioning behavior of organic compounds, in aquatic systems. He has been principal investigator on more than ten federally funded research grants (predominantly National Science Foundation), and has led five state-funded projects examining the fate and transport of selenium and mercury in the Great Salt Lake and surrounding wetlands. Dr. Johnson has produced eighty five peer reviewed publications in top-tier journals, with over 2100 citations of this work to date.
Where: 4100B HSEB