rdf-syntax-grammar
mods:
  schema location: http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
  title info:
    title: Mechanisms of Flagellar Switch Activation
  name:
    name part: Gupta, Rachit
    role:
      role term: creator
    role:
      role term: author.
  name:
    name part: Lele, Pushkar
    role:
      role term: thesis advisor.
  name:
    name part: Texas A&M University
    role:
      role term: degree granting institution.
  type of resource: text
  genre: bibliography
  origin info:
    place:
      place term: txu
    date issued: 2023
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: remote
    extent: 1 online resource.
  abstract: Bacteria are amongst the most resilient living organisms that rapidly and robustly adapt to different types of environments. Their remarkable success in colonizing almost all parts of the planet is aided in part by their ability to swim. Escherichia coli swim with the aid of rotary motors that rotate extracellular filaments called the flagella. The flagellar motor carries a switch complex that reverses the direction of rotation of the motor between clockwise (CW) and counterclockwise (CCW). Switching is necessary for the cell to navigate towards favorable chemical environments - a process called chemotaxis. The key to successful chemotaxis is homeostasis in switching, which is enabled by multiple mechanisms. In this work, we have focused on explaining the unknown mechanisms that activate the switch. We employed single-cell level assays in combination with imaging and particle-tracking algorithms to probe these activation mechanisms. With these tools, we have found that a major signaling molecule in the human gastrointestinal tract, indole, promotes switching by directly interacting with the motor. Based on our findings, we propose that indole-based activation of the switch possibly predated the coupling of the chemotaxis network with the flagellar motor. Next, we investigated the mechanisms by which the motor switches its direction of rotation. Specifically, we tested a recently proposed model in which a part of the switch complex, a homo-oligomeric ring called FliG, dramatically expands and contracts to facilitate switching. Our preliminary findings do not support this model. Finally, we probed if the morphology of the cell influenced the adaptability of the flagellar switch, finding a weak degradation in the latter when cells became longer. We expect our work to provoke exciting research undertakings in the future to probe the role of metabolites and antibiotics in chemotaxis and bacterial infections. The electronic version of this dissertation is accessible from …
  note: by Rachit Gupta.
  note: "Major Subject: Chemical Engineering"
  note: Includes vita.
  note: Doctor of Philosophy Texas A&M University 2022 https://hdl.handle.net/1969.1/198578
  note: Includes bibliographical references.
  note: Text (Dissertation)
  subject:
    topic: Major Chemical Engineering
  subject:
    topic: Bacterial Motility
  subject:
    topic: Flagellar motor
  subject:
    topic: Chemotaxis
  subject:
    topic: Indole
  subject:
    topic: Proton-Motive force
  subject:
    topic: bacterial energetics
  identifier: https://hdl.handle.net/1969.1/198578
  record info:
    record content source: TXA
    record creation date: 240924
    record change date: 20250326141433.8
    record identifier: in00005621339
    language of cataloging:
      language term: eng