The keynote address will be given at 7:15 p.m. Friday, October 27, at the Fayetteville Town Center.
Invited faculty talks will be given from 1:30-3:00 p.m. Friday, October 27, in the Chancellor Hotel, Eureka Springs Ballroom, on the Fayetteville Square. Abstracts are posted below.
Invited student talks will be given from 3:15-5:00 p.m. Friday, October 27, in the Chancellor Hotel, assigned rooms, on the Fayetteville Square. (Please see the link to “Invited Student Speakers.”)
Keynote Speaker (Friday Evening – Town Center – 7:15 pm)
TITLE: Optical atomic clock and applications
ABSTRACT: Emerging technologies based on quantum state engineering of ultra-cold matter and precise control of laser field have revolutionized a new generation of atomic clocks with accuracy at the 18th digit. This progress has benefited greatly from microscopic understandings of atomic interactions in the quantum regime and the capability of controlling optical phase coherence over many seconds. The unified front of precision metrology and quantum physics will allow us to explore complex quantum systems, test the fundamental laws of nature, search for new physics, and find unexpected applications.
BIOLOGY (1:35 pm Friday):
TITLE: Harnessing the power of omic approaches for understanding the role of the inositol pathway to ascorbate in plant growth and stress tolerance.
ABSTRACT: Food security is currently one of the major challenges that we are facing as a species. Understanding plant responses and adaptations to abiotic and biotic stresses is key to maintaining and improving crop yields, and this is even more critical considering the different projections of climate change. Vitamin C (L-ascorbic acid, AsA) is a major antioxidant that modulates multiple developmental and defense responses in plants. This small molecule also plays a key role at protecting plant tissues against the damage caused by reactive oxygen species. In plants, ascorbate is synthesized by a complex metabolic network and, transcriptional profiling studies in multiple plant species suggests that the AsA pathways may differ in their responsiveness to stresses, but their relative contributions to stress adaptation are not yet fully understood. We have demonstrated that engineering high ascorbate in Arabidopsis and rice leads to plants with enhanced growth rate, biomass accumulation, and tolerance to multiple abiotic stresses including salinity, heat, cold, water limitation, and environmental pollutants. In this work we are leveraging genomics, transcriptomics and phenomics approaches to elucidate the mechanisms behind the enhanced growth phenotype we have observed in our high AsA Arabidopsis lines. We will also present our progress on the characterization of a new gluconolactonase (GNL) in plants. This is the third enzyme involved in the conversion of myo-inositol to ascorbate. Eighteen putative GNLs were identified in Arabidopsis, one of which, AtGNL, possesses a chloroplastic signal peptide. Chloroplasts can accumulate up to 50 mM AsA but until now no chloroplastic AsA biosynthetic genes have been described. We have characterized the first plant GNL enzyme in vitro and in planta. Knockouts on this gene had lower foliar vitamin C and stunted growth compared to controls. The functional gene restored the phenotype of the knockouts, and those plants had higher AsA content, and enhanced photosynthetic capacity and seed yield. Next steps in this research include testing the effect of the constitutive expression of this GNL gene in crop plants.
CHEMISTRY (2:05 pm Friday):
TITLE: Novel inhibitors of enzymes in the dopamine pathway: Modelling and synthesis.
ABSTRACT: The many enzymes involved in the metabolism of dopamine have similar substrates, making the design of selective ligands or inhibitors for specific enzymes difficult. This project entails the design, computational analysis, synthesis, and testing of a library of compounds for their ability to inhibit a suite of enzymes involved in the dopamine pathway. The compounds in our library start with a basic catecholaminic core, with various groups added the aromatic ring and substitution of neutral and charged moieties for the ethylamine tail. The crystal structures for the enzymes catechol-O-methyltransferase (COMT), DOPA decarboxylase, monoamine oxidase B, aldehyde dehydrogenase, phenylalanine hydroxylase, and tyrosine hydroxylase were obtained from the protein databank. Our novel ligands were placed in the active site in an initial confirmation similar to experimentally bound ligands. The structures were then optimized using the M062X or M06L methods with the 6–31+G*basis set including implicit solvation and relaxed ligand side chains. Interaction energies between each optimized ligand and the active site were then calculated with the same methods and the 6–311+G* basis set. Desolvation effects on the ligands were also taken into account. Several of the ligands from our library have been synthesized and tested experimentally in an enzymatic assay with COMT. These results have been correlated with the computational results to design more selective inhibitors in the future.
PHYSICS (2:35 pm Friday):
TITLE: Suppression of Radiation-Induced Chromosome Damage by γ-Tocotrienol (GT3) and the Role of Microgravity
ABSTRACT: One of the major risks during manned space mission is combined exposure to ionizing radiation (IR) and microgravity. IR generates reactive oxygen species which cause DNA double-strand breaks (DSBs) that are responsible for cytogenetic alterations, known to associate with cancer and cardiovascular disease, two major causes of death. We measured DSB formation in irradiated primary human umbilical vein endothelial cells (HUVECs) by quantifying the formation of γ-H2AX foci. Chromosomal aberrations (CAs) were analyzed in irradiated HUVECs and in the bone marrow cells of irradiated mice by conventional and fluorescence-based chromosome painting techniques. Gene expression was measured in HUVECs with quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). We find that pretreatment with vitamin E isoform γ-tocotrienol (GT3) reduced DSB formation in HUVECS, and decreased CAs in HUVECs and mouse bone marrow cells after irradiation. GT3 should be explored as a therapeutic to reduce the risk of developing genetic diseases after radiation exposure. Furthermore, no systematic study has been undertaken to investigate whether microgravity differentially modulates the expression of endothelial dysfunction markers in irradiated endothelial cells. To gain insight into this we subjected human endothelial cells under simulated microgravity after exposure to Ionizing Radiation. To simulate a low shear microgravity environment, endothelial cells were grown on micro-carrier beads and subsequently subjected to a rotary culture systems. We observed microgravity induces morphological changes in endothelial cells and enhances radiation-induced endothelial cell killing. In addition, IR plus microgravity causes differential expression of E-selectin, Pecam1, Vcam1, Vegf, and Icam1 than IR alone. These results suggest that microgravity modifies the effect of Ionizing Radiation on endothelial cells.