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Browsing by Author "Steele, Erika"

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    Co-culturing experiments reveal the uptake of myo-inositol phosphate synthase (EC 5.5.1.4) in an inositol auxotroph of Saccharomyces cerevisiae
    (BMC, 2021) Steele, Erika; Alebous, Hana D.; Vickers, Macy; Harris, Mary E.; Johnson, Margaret D.; University of Alabama Tuscaloosa; University of Jordan
    BackgroundMyo-Inositol Phosphate Synthase (MIP) catalyzes the conversion of glucose 6- phosphate into inositol phosphate, an essential nutrient and cell signaling molecule. Data obtained, first in bovine brain and later in plants, established MIP expression in organelles and in extracellular environments. A physiological role for secreted MIP has remained elusive since its first detection in intercellular space. To provide further insight into the role of MIP in intercellular milieus, we tested the hypothesis that MIP may function as a growth factor, synthesizing inositol phosphate in intercellular locations requiring, but lacking ability to produce or transport adequate quantities of the cell-cell communicator. This idea was experimentally challenged, utilizing a Saccharomyces cerevisiae inositol auxotroph with no MIP enzyme, permeable membranes with a 0.4 mu m pore size, and cellular supernatants as external sources of inositol isolated from S. cerevisiae cells containing either wild-type enzyme (Wt-MIP), no MIP enzyme, auxotroph (Aux), or a green fluorescent protein (GFP) tagged reporter enzyme (MIP- GFP) in co- culturing experiments.ResultsResulting cell densities and microscopic studies with corroborating biochemical and molecular analyses, documented sustained growth of Aux cells in cellular supernatant, concomitant with the uptakeof MIP, detected as MIP-GFP reporter enzyme. These findings revealed previously unknown functions, suggesting that the enzyme can: (1) move into and out of intercellular space, (2) traverse cell walls, and (3) act as a growth factor to promote cellular proliferation of an inositol requiring cell.ConclusionsCo-culturing experiments, designed to test a probable function for MIP secreted in extracellular vesicles, uncovered previously unknown functions for the enzyme and advanced current knowledge concerning spatial control of inositol phosphate biosynthesis. Most importantly, resulting data identified an extracellular vesicle (a non-viral vector) that is capable of synthesizing and transporting inositol phosphate, a biological activity that can be used to enhance specificity of current inositol phosphate therapeutics.
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    Strategies for Addressing Aging Infrastructure and Workforce Challenges in Water Distribution Systems
    (University of Alabama Libraries, 2025) Clayton, Jonathan Gerald; Terry, Leigh G.
    This dissertation focuses on identifying steps water utilities can take to either prevent or manage the effects of the aging water workforce and aging distribution systems. In particular, career education and outreach, leak management, and mitigation of arsenic contamination in aging systems are discussed. Chapter 1 is a brief introduction to issues posed by aging workforce and infrastructure workforce challenges in these contexts. Chapter 2, titled "Train the Trainers: Do Researcher and Professional Collaborations with Teachers Increase Student Career Interest?--A Mixed Methods Study" was accepted by Journal of STEM Outreach and investigates methods for increasing student interest in careers within environmental engineering and the water sector. Chapter 4 is under submission and is titled "Sample-Informed Arsenic Spike Prediction in a Hungarian Drinking Water Distribution Network Using Machine Learning." Chapter 3 has been published in AWWA Water Science and is titled "Delayed pipe replacement halves environmental impacts but quadruples water loss." Chapter 3 covers the life cycle impacts of pipe replacement on environmental and health factors and provides suggestions for effective management of leaks and aging pipes. Chapter 4 focuses on identifying pathways of arsenic contamination in drinking water distribution systems and methods for abating consumer exposure to arsenic. Chapter 5 summarizes the conclusions of the dissertation and provides recommendations for future research.