<mods:mods xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-7.xsd"><mods:titleInfo><mods:title>A Novel Swarming Bacterial Strain Exhibits Unique Biophysical and Probiotic Properties</mods:title></mods:titleInfo><mods:name type="personal"><mods:namePart>Chen, Weijie</mods:namePart><mods:role><mods:roleTerm type="text">creator</mods:roleTerm></mods:role></mods:name><mods:name type="personal"><mods:namePart>Tang, Jay</mods:namePart><mods:role><mods:roleTerm type="text">Advisor</mods:roleTerm></mods:role></mods:name><mods:name type="personal"><mods:namePart>Pelcovits, Robert</mods:namePart><mods:role><mods:roleTerm type="text">Reader</mods:roleTerm></mods:role></mods:name><mods:name type="personal"><mods:namePart>Mani, Sridhar</mods:namePart><mods:role><mods:roleTerm type="text">Reader</mods:roleTerm></mods:role></mods:name><mods:name type="corporate"><mods:namePart>Brown University. Department of Physics</mods:namePart><mods:role><mods:roleTerm type="text">sponsor</mods:roleTerm></mods:role></mods:name><mods:originInfo><mods:copyrightDate>2021</mods:copyrightDate></mods:originInfo><mods:physicalDescription><mods:extent>, None p.</mods:extent><mods:digitalOrigin>born digital</mods:digitalOrigin></mods:physicalDescription><mods:note type="thesis">Thesis (Ph. D.)--Brown University, 2021</mods:note><mods:genre authority="aat">theses</mods:genre><mods:abstract>Bacterial swarming is one of the motility types where groups of bacteria use flagella to migrate swiftly on a wet surface. Physically, swarming is a natural example of active matter. Due to high cell density, bacterial cells in the swarm collide and align with each other, forming jets and swirls. Swarming is associated with bacterial pathogenesis and antibiotic resistance. Swarming is also known to be a phenotype inversely regulated with biofilm formation. Herein, we report a study on the biophysical properties of a novel swarming bacterial strain Enterobacter sp. SM3. When confined by PDMS microwells of specific sizes mounted on an agar surface, SM3 under swarming condition exhibits a “single-swirl” motion pattern distinct from “multi-swirls” formed by its concentrated planktonic counterpart. We hypothesized that a “rafting behavior” of the swarming bacteria upon dilution might account for the motion pattern difference. We verified the conjecture via numerical simulations where swarming cells are modeled with stronger cell-cell alignment. The simulations indeed produce single swirls for stronger alignments and multiple swirls as the alignment strength is tuned down.
In addition to the biophysical property, SM3 is also found to have probiotic effect against intestinal inflammation due to its swarming phenotype. We find that bacterial swarmers frequently emerge during intestinal stress and SM3 was isolated from colitic mouse feces as a dominant swarming strain. SM3, in contrast to its swarming-deficient, but swimming-competent isogenic strains abrogated intestinal inflammation in mice. Treatment of colitic mice with SM3, but not its mutants, enriched beneficial fecal anaerobes belonging to the family of Bacteroidales S24-7. In vitro co-culture assay between S24-7 and SM strains together with the race assay on tissue implies that bacterial swarming might add advantage to SM3’s access to S24-7 in the intestines and the symbiosis of the two results in the protection effect. These findings suggest a new paradigm in which intestinal stress allows for the emergence of swarming bacteria, which can in turn heal intestinal inflammation.</mods:abstract><mods:subject authority="fast" authorityURI="http://id.worldcat.org/fast" valueURI="http://id.worldcat.org/fast/00825152"><mods:topic>Bacteria</mods:topic></mods:subject><mods:subject><mods:topic>bacterial motility</mods:topic></mods:subject><mods:subject><mods:topic>swarming</mods:topic></mods:subject><mods:language><mods:languageTerm authority="iso639-2b">English</mods:languageTerm></mods:language><mods:recordInfo><mods:recordContentSource authority="marcorg">RPB</mods:recordContentSource><mods:recordCreationDate encoding="iso8601">20210607</mods:recordCreationDate></mods:recordInfo><mods:typeOfResource authority="primo">dissertations</mods:typeOfResource></mods:mods>