Bulletin of the American Physical Society
2018 Joint Fall Meeting of the Texas Sections of APS, AAPT and Zone 13 of the SPS
Volume 63, Number 18
Friday–Saturday, October 19–20, 2018; University of Houston, Houston, Texas
Session K02: Biophysics and Soft Matter II |
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Chair: Timothy Burt, University of Houston Room: Science and Engineering Classroom (SEC) 102 |
Saturday, October 20, 2018 10:00AM - 10:36AM |
K02.00001: Unveiling Molecular Mechanisms of Kinesin-5 Function Using Multiscale Computational Techniques Invited Speaker: Aram Davtyan Molecular motor protein Kinesin-5 (Eg5) is a member of kinesin superfamily that is critical for bipolar spindle assembly and spindle maintenance during mitosis. As a result it is a promising chemotherapeutic target for cancer treatment. While a number of small-molecule drugs that interact with Eg5 have been identified, little is known about the molecular mechanisms by which they inhibit Eg5 function. Furthermore, multi-motor systems can exhibit qualitatively diverse behavior for drugs that have similar mode of action, in some cases showing distinct dependence of motor velocity on drug concentration. We have studied molecular mechanisms behind function of Eg5 motor in absence and presence of different small-molecular drugs using computational modeling techniques and analytical calculations. Our simulations have revealed pronounced differences in how each drug affects Eg5 mechanochemical cycle and its processivity, while out analytical calculations established a rigorous connection between simulations and experiments. Besides apparent fundamental value this work has significant implications for clinical applications, where in depth understanding of Eg5-drug interaction is important. |
Saturday, October 20, 2018 10:36AM - 10:48AM |
K02.00002: Copper-Cysteamine Nanoparticles As New Radio/Photosensitizer With Low Sunlight Toxicity Lalit Chudal, Nil Pandey, Jonathan Phan, Wei Chen Photodynamic therapy is a new cancer treatment modality that uses singlet oxygen and other reactive oxygen species to kill cancerous cells. However, most conventional photosensitizers are toxic to not only cancerous cells but also to normal cells. Most of these PSs can be excited by UV-Vis light and therefore results in unwanted toxicity under sunlight and bright room light exposure. Therefore, PDT treated patients are required to avoid bright light for up to six weeks. Copper cysteamine(Cu-Cy) nanoparticle, which was invented by our group in 2014, is a new type of photosensitizer and a novel radiosensitizer that can be activated by X-ray, UV-light, microwave, and ultrasound to produce singlet oxygen and other types of reactive oxygen species for cancer treatment. The Cu-Cy nanoparticle has strong absorption in UV-region but not in the visible region and hence may not produce ROS under sunlight. In the present article, we report comparative toxicity study of Cu-Cy and PPIX (an FDA approved PSs) and show that while Cu-Cy is toxic to cancer cells, it is highly safer to normal cells. On the other hand, PPIX is toxic to both cancer and normal cells. |
Saturday, October 20, 2018 10:48AM - 11:00AM |
K02.00003: Tracking Branched Chain Amino Acid Transferase (BCAT) Activity in Cancer Cells via 13C NMR Spectroscopy Christopher Parish, Peter J Niedbalski, Fatemeh Khashami, Qing Wang, Aya Cloyd, Lloyd Lumata Carbon-13 nuclear magnetic resonance (NMR) spectroscopy is a powerful technique for identifying and tracking biological compounds in a chemical reaction. In studies of cancer, NMR spectroscopy is particularly useful because it has the specificity to identify and monitor specific biochemical changes in the cellular environment. In this work, we have used 13C NMR to investigate the abnormal metabolic activity of glioblastoma or cancerous astrocytes by using 13C-enriched alpha-ketoisocaproate (aKIC) and 13C-alpha-ketoisovalerate (aKIV). The enzyme called branched chain amino acid transferase is overexpressed in these cells and thus, there is an overproduction of leucine from aKIC and valine from aKIV. The metabolic kinetics and potential diagnostic applications of these potential glioblastoma biomarkers will be discussed. |
Saturday, October 20, 2018 11:00AM - 11:12AM |
K02.00004: NMR Spectroscopy of Alanine Metabolism in Glioblastoma Cells Qing Wang, Sarah Chieng, Christopher Parish, Fatemeh Khashami, Lloyd Lumata Nuclear magnetic resonance (NMR) is widely-used spectroscopic tool because of its high specificity and use of non-destructive RF waves. Tracking aberrant metabolism in cancer cells is one of the many applications of NMR. The wide chemical shift dispersion of the carbon-13 nucleus allows NMR spectral distinction of the specific metabolites or biochemicals in cancer cells and tissues. In this study, we have investigated the metabolic fate of the amino acid 13C-alanine in glioblastoma or brain cancer cells. Our NMR data show that alanine is metabolized quickly into lactate, with pyruvate production as an intermediate metabolite. These results is reminiscent of the Warburg effect wherein there is an overproduction of lactic acid from glucose or pyruvate. The metabolic kinetics of this biochemical reaction will be discussed in the context of potential diagnostic application for glioblastoma. |
Saturday, October 20, 2018 11:12AM - 11:24AM |
K02.00005: The pEpitope Model Quantifies a Novel Antigenic Distance to Predict Influenza Vaccine Effectiveness Melia E Bonomo, Rachel Y Kim, Michael W Deem Though influenza affects millions of individuals worldwide each year, vaccination has been shown to prevent hospitalizations, lessen severe illness outcomes, and reduce the public health burden. Minimizing the antigenic differences between the vaccine virus and the circulating strains ensures the vaccine will adequately prime the immune system against infection. We developed a theory of the human antibody response to influenza infection following vaccination that produced a robust measure of antigenic distance, called the pEpitope model. We calibrated this model with A(H3N2) epidemiology data over the past 47 years, the past decade, and in recent studies from the US Centers for Disease Control and Prevention Influenza Vaccine Effectiveness Network; the coefficients of determination with vaccine effectiveness were 0.75, 0.78, and 0.92, respectively. Our analysis of A(H3N2) strains circulating between September 2017-May 2018 identified the emergence of a new quasispecies cluster that is sufficiently distant from the 2018-2019 vaccine. The pEpitope model is a valuable tool that enhances influenza vaccine virus selection and development. |
Saturday, October 20, 2018 11:24AM - 11:36AM |
K02.00006: Application of a Quantum Toy Model for Proton Transfer on the Molecular Scale Derek A Smith, Samina Masood A simplified toy model based on the principals of quantum tunneling is applied to biological systems involving proton transfer, such as with nucleotide tautomerization. In this case, the changed location of a Hydrogen atom within the molecule can be treated as proton transfer, and the toy model attempts to explain the transfer process through the use of relative potentials. |
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