College of Natural and Health Sciences (CNHS)
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The sciences afford the opportunity for exploration and discovery in the pursuit of new knowledge, understanding systems in the physical and natural world, and for bettering the human condition. With the challenges the world faces, there has never been a better time to pursue an education in the sciences, health care or sport studies. Scientists, technicians and caregivers are in high demand. The College of Natural and Health Sciences offers rigorous, high quality curricula designed to prepare students for the challenges and opportunities that lie ahead.
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Item AGGREGATION OF SiC-X GRAINS IN SUPERNOVA EJECTA(The American Astronomical Society, 2009-10-20) Deneault, Ethan A.-N.We present a model for the formation of silicon carbide aggregates within the expanding and cooling supernova remnant. SiC type-X (SiC-X) grains measured in the laboratory at a high spatial resolution have been found to be aggregates of smaller crystals which are isotopically homogenous. The initial condensation of SiC in the ejecta occurs within an interior dense shell of material which is created by a reverse shock which rebounds from the core–envelope interface. A subsequent reverse shock accelerates the grains forward, but the gas drag from the ejecta on the rapidly moving particles limits their travel distance. By observing the effects of gas drag on the travel distance of grains, we propose that supernova grain aggregates form from material that condensed in a highly localized region, which satisfies the observational evidence of isotopic homogeneity in SiC-X grains.Item BRCA1 185delAG Mutation Enhances Interleukin-1𝛽 Expression in Ovarian Surface Epithelial Cells(Hindawi Publishing Corporation, 2015-08-19) Woolery, Kamisha T.Familial history remains the strongest risk factor for developing ovarian cancer (OC) and is associated with germline BRCA1 mutations, such as the 185delAG founder mutation. We sought to determine whether normal human ovarian surface epithelial (OSE) cells expressing the BRCA1 185delAG mutant, BRAT, could promote an inflammatory phenotype by investigating its impact on expression of the proinflammatory cytokine, Interleukin-1𝛽 (IL-1𝛽). Cultured OSE cells with and without BRAT were analyzed for differential target gene expression by real-time PCR, western blot, ELISA, luciferase reporter, and siRNA assays.We found that BRAT cells expressed increased cellular and secreted levels of active IL-1𝛽. BRAT-expressing OSE cells exhibited 3-fold enhanced IL- 1𝛽 mRNA expression, transcriptionally regulated, in part, through CREB sites within the (−1800) to (−900) region of its promoter. In addition to transcriptional regulation, BRAT-mediated IL-1𝛽 expression appears dualistic through enhanced inflammasomemediated caspase-1 cleavage and activation of IL-1𝛽. Further investigation is warranted to elucidate the molecularmechanism(s) of BRAT-mediated IL-1𝛽 expression since increased IL-1𝛽 expression may represent an early step contributing to OC.Item BRCA1 185delAG Mutation Enhances Interleukin-1𝛽 Expression in Ovarian Surface Epithelial Cells(BioMed Research International, Hindawi Publishing Corporation, 2015-06-17) Woolery, Kamisha T.; Mohamed, Mai; Linger, Rebecca J.; Dobrinski, Kimberly P.; Roman, Jesse; Kruk, Patricia A.Familial history remains the strongest risk factor for developing ovarian cancer (OC) and is associated with germline BRCA1 mutations, such as the 185delAG founder mutation. We sought to determine whether normal human ovarian surface epithelial (OSE) cells expressing the BRCA1 185delAG mutant, BRAT, could promote an inflammatory phenotype by investigating its impact on expression of the proinflammatory cytokine, Interleukin-1𝛽 (IL-1𝛽). Cultured OSE cells with and without BRAT were analyzed for differential target gene expression by real-time PCR, western blot, ELISA, luciferase reporter, and siRNA assays.We found that BRAT cells expressed increased cellular and secreted levels of active IL-1𝛽. BRAT-expressing OSE cells exhibited 3-fold enhanced IL- 1𝛽 mRNA expression, transcriptionally regulated, in part, through CREB sites within the (−1800) to (−900) region of its promoter. In addition to transcriptional regulation, BRAT-mediated IL-1𝛽 expression appears dualistic through enhanced inflammasomemediated caspase-1 cleavage and activation of IL-1𝛽. Further investigation is warranted to elucidate the molecularmechanism(s) of BRAT-mediated IL-1𝛽 expression since increased IL-1𝛽 expression may represent an early step contributing to OC.Item Combining Astrometry and Elemental Abundances: The Case of the Candidate Pre-Gaia Halo Moving Groups G03-37, G18-39, and G21-22*(The Astronomical Journal, 2021-08-18) Schuler, Simon C.; Andrews, Jeff J.; Clanzy II, Vincent R.; Mourabit, Mohammed; Chanamé, Julio; Agüeros, Marcel A.While most moving groups are young and nearby, a small number have been identified in the Galactic halo. Understanding the origin and evolution of these groups is an important piece of reconstructing the formation history of the halo. Here we report on our analysis of three putative halo moving groups: G03-37, G18-39, and G21-22. Based on Gaia EDR3 data, the stars associated with each group show some scatter in velocity (e.g., Toomre diagram) and integrals of motion (energy, angular momentum) spaces, counter to expectations of moving-group stars. We choose the best candidate of the three groups, G21-22, for follow-up chemical analysis based on high-resolution spectroscopy of six presumptive members. Using a new Python code that uses a Bayesian method to self-consistently propagate uncertainties from stellar atmosphere solutions in calculating individual abundances and spectral synthesis, we derive the abundances of α- (Mg, Si, Ca, Ti), Fe-peak (Cr, Sc, Mn, Fe, Ni), odd-Z (Na, Al, V), and neutron-capture (Ba, Eu) elements for each star. We find that the G21-22 stars are not chemically homogeneous. Based on the kinematic analysis for all three groups and the chemical analysis for G21-22, we conclude the three are not genuine moving groups. The case for G21-22 demonstrates the benefit of combining kinematic and chemical information in identifying conatal populations when either alone may be insufficient. Comparing the integrals of motion and velocities of the six G21-22 stars with those of known structures in the halo, we tentatively associate them with the Gaia-Enceladus accretion event.Item Condensation of Silicon Carbide in Supernova Ejecta(The American Astronomical Society, 2017-07-01) Deneault, EthanWe present a kinetic model of the formation of silicon carbide (SiC) in the expanding and cooling outflows of Type II supernova ejecta. We assume an ejecta cloud composed of a mixture of Si, C, and O in the gas phase, with the initial temperature, density, and composition as tunable parameters. The condensation of diatomic SiC into (SiC)2 molecules provides the abundance of nucleation sites for the eventual condensation of larger SiC solids and dust grains. We find that the abundance of these nucleation sites, formed after the first 1700 days after the explosion, is strongly governed by the C/Si ratio, the density of the gas, and the rate of cooling in the ejecta.Item Cross-Species Array Comparative Genomic Hybridization Identifies Novel Oncogenic Events in Zebrafish and Human Embryonal Rhabdomyosarcoma(PLoS Genetics, Public Library of Science, 2013-08-29) Chen, Eleanor Y.; Dobrinski, Kimberly P.; Brown, Kim H.; Clagg, Ryan; Edelman, Elena; Ignatius, Myron S.; Chen, Jin Yun Helen; Brockmann, Jillian; Nielsen, G. Petur; Ramaswamy, Sridhar; Keller, Charles; Lee, Charles; Langenau, David M.Human cancer genomes are highly complex, making it challenging to identify specific drivers of cancer growth, progression, and tumor maintenance. To bypass this obstacle, we have applied array comparative genomic hybridization (array CGH) to zebrafish embryonal rhabdomyosaroma (ERMS) and utilized cross-species comparison to rapidly identify genomic copy number aberrations and novel candidate oncogenes in human disease. Zebrafish ERMS contain small, focal regions of low-copy amplification. These same regions were commonly amplified in human disease. For example, 16 of 19 chromosomal gains identified in zebrafish ERMS also exhibited focal, low-copy gains in human disease. Genes found in amplified genomic regions were assessed for functional roles in promoting continued tumor growth in human and zebrafish ERMS – identifying critical genes associated with tumor maintenance. Knockdown studies identified important roles for Cyclin D2 (CCND2), Homeobox Protein C6 (HOXC6) and PlexinA1 (PLXNA1) in human ERMS cell proliferation. PLXNA1 knockdown also enhanced differentiation, reduced migration, and altered anchorage-independent growth. By contrast, chemical inhibition of vascular endothelial growth factor (VEGF) signaling reduced angiogenesis and tumor size in ERMS-bearing zebrafish. Importantly, VEGFA expression correlated with poor clinical outcome in patients with ERMS, implicating inhibitors of the VEGF pathway as a promising therapy for improving patient survival. Our results demonstrate the utility of array CGH and cross-species comparisons to identify candidate oncogenes essential for the pathogenesis of human cancer.Item The Genome of Deep-Sea Vent Chemolithoautotroph Thiomicrospira crunogena XCL-2(PLoS Biology, Public Library of Science, 2006-12) Scott, Kathleen M.; Sievert, Stefan M.; Abri, Fereniki N.; Ball, Lois A.; Barrett, Chantell J.; Blake, Rodrigo A.; Amanda J., Boller; Chain, Patrick S. G.; Clark, Justin A.; Davis, Carisa R.; Detter, Chris; Do, Kimberly F.; Dobrinski, Kimberly P.; Faza, Brandon I.; Fitzpatrick, Kelly A.; Freyermuth, Sharyn K.; Harmer, Tara L.; Hauser, Loren J.; Hugler, Michael; Kerfeld, Cheryl A.; Klotz, Martin G.; Kong, William W.; Land, Miriam; Lapidus, Alla; Larimer, Frank W.; Longo, Dana L.; Lucas, Susan; Malfatti, Stephanie A.; Massey, Steven E.; Martin, Darlene D.; McCuddin, Zoe; Meyer, Folker; Moore, Jessica L.; Ocampo, Luis H. Jr.; Paul, John H.; Paulsen, Ian T.; Reep, Douglas K.; Ren, Qinghu; Ross, Rachel L.; Sato, Priscila Y.; Thomas, Phaedra; Tinkham, Lance E.; Zeruth, Gary T.Presented here is the complete genome sequence of Thiomicrospira crunogena XCL-2, representative of ubiquitous chemolithoautotrophic sulfur-oxidizing bacteria isolated from deep-sea hydrothermal vents. This gammaproteobacterium has a single chromosome (2,427,734 base pairs), and its genome illustrates many of the adaptations that have enabled it to thrive at vents globally. It has 14 methyl-accepting chemotaxis protein genes, including four that may assist in positioning it in the redoxcline. A relative abundance of coding sequences (CDSs) encoding regulatory proteins likely control the expression of genes encoding carboxysomes, multiple dissolved inorganic nitrogen and phosphate transporters, as well as a phosphonate operon, which provide this species with a variety of options for acquiring these substrates from the environment. Thiom. crunogena XCL-2 is unusual among obligate sulfur-oxidizing bacteria in relying on the Sox system for the oxidation of reduced sulfur compounds. The genome has characteristics consistent with an obligately chemolithoautotrophic lifestyle, including few transporters predicted to have organic allocrits, and Calvin-Benson-Bassham cycle CDSs scattered throughout the genome.Item Genomic Amplification of an Endogenous Retrovirus in Zebrafish T-Cell Malignancies(Advances in Hematology, Hindawi Publishing Corporation, 2012-04-17) Frazer, J. Kimble; Batchelor, Lance A.; Bradley, Diana F.; Brown, Kim H.; Dobrinski, Kimberly P.; Lee, Charles; Trede, Nikolaus S.Genomic instability plays a crucial role in oncogenesis. Somatically acquired mutations can disable some genes and inappropriately activate others. In addition, chromosomal rearrangements can amplify, delete, or even fuse genes, altering their functions and contributing to malignant phenotypes. Using array comparative genomic hybridization (aCGH), a technique to detect numeric variations between different DNA samples, we examined genomes from zebrafish (Danio rerio) T-cell leukemias of three cancerprone lines. In all malignancies tested, we identified recurring amplifications of a zebrafish endogenous retrovirus. This retrovirus, ZFERV, was first identified due to high expression of proviral transcripts in thymic tissue from larval and adult fish.We confirmed ZFERV amplifications by quantitative PCR analyses of DNA from wild-type fish tissue and normal and malignant D. rerio T cells. We also quantified ZFERV RNA expression and found that normal and neoplastic T cells both produce retrovirally encoded transcripts, but most cancers show dramatically increased transcription. In aggregate, these data imply that ZFERV amplification and transcription may be related to T-cell leukemogenesis. Based on these data and ZFERV’s phylogenetic relation to viruses of the murine-leukemia-related virus class of gammaretroviridae, we posit that ZFERV may be oncogenic via an insertional mutagenesis mechanism.