{"548821":{"#nid":"548821","#data":{"type":"event","title":"PhD Defense by Eryn Bernardy","body":[{"value":"\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003EIn partial fulfillment of the Requirements for the Degree of\u003Cbr \/\u003E \u003Cbr \/\u003E Doctor of Philosophy in Biology\u003Cbr \/\u003E \u003Cbr \/\u003E \u003Cstrong\u003EEryn Bernardy\u003C\/strong\u003E\u003Cbr \/\u003E \u003Cbr \/\u003E Will defend her thesis\u003Cbr \/\u003E \u003Cbr \/\u003E \u003Cstrong\u003E\u0022Natural competence and Type VI secretion in Vibrio cholerae\u0022\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003ETuesday, July 12\u003Csup\u003Eth\u003C\/sup\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E1:00pm\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003EPetite Institute for Bioengineering and Biosciences (IBB), room 1128.\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003E\u003Cbr \/\u003E Thesis Advisor:\u003Cbr \/\u003E Dr. Brian Hammer (School of Biology)\u003Cbr \/\u003E \u003Cbr \/\u003E Committee Members:\u003Cbr \/\u003E Dr. Frank Stewart\u0026nbsp; (School of Biology)\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003EDr. Thomas DiChristina (School of Biology)\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003EDr. William Ratcliff (School of Biology)\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp align=\u0022center\u0022\u003EDr. Cheryl Tarr (Centers for Disease Control and Prevention)\u003Cbr \/\u003E \u003Cbr \/\u003E Abstract:\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EThe waterborne bacterium \u003Cem\u003EVibrio cholerae,\u003C\/em\u003E responsible for epidemics of cholera diarrhea, associates with the human gut and with chitinous surfaces in aquatic reservoirs. Prior studies of two clinical \u003Cem\u003EV. cholerae\u003C\/em\u003E isolates revealed that natural competence for genetic transformation, a horizontal gene transfer mechanism, requires the chitin-induced TfoX regulator, and quorum sensing transcription factor HapR made at high cell density. To further understand this regulation, I helped identify, in a genetic screen, CytR, a new positive regulator required for competence gene expression and natural transformation. Recently, this complex regulatory network in \u003Cem\u003EV. cholerae\u003C\/em\u003E was shown to also control a type VI secretion system (T6SS) that allows contact-dependent killing of other bacteria by injecting toxic proteins.\u0026nbsp; I characterized a diverse set of sequenced \u003Cem\u003EV. cholerae\u003C\/em\u003E isolates, revealing that transformation was rare in all isolates, while constitutive type VI killing was common among environmental but not clinical isolates. These latter results were consistent with a \u201cpathoadaptive\u201d model that tight regulation is beneficial in a host, while constitutive killing is advantageous in the environment. We hypothesized that two sequenced \u003Cem\u003EV. cholerae\u003C\/em\u003E isolates with distinct T6SSs could generate structured populations from initially well-mixed conditions by killing competitors, but not kin. Indeed, when both isolates were rendered T6SS\u003Csup\u003E-\u003C\/sup\u003E, a well-mixed population was observed via fluorescence microscopy. In contrast, mutual killing generated clonal patches with each isolate segregating into distinct groups. Structural dynamics were recapitulated with three mathematical models and a cooperation model developed supports that this assortment promotes cooperation among kin. My work in \u003Cem\u003EV. cholerae\u003C\/em\u003E has helped elucidate a complex regulatory network controlling multiple important phenotypes, diversity of these phenotypes among species members, and ecological consequences of antagonistic microbial interactions in the environment.\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"Natural competence and Type VI secretion in Vibrio cholerae"}],"uid":"27707","created_gmt":"2016-06-28 14:57:19","changed_gmt":"2016-10-08 02:18:11","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2016-07-12T14:00:00-04:00","event_time_end":"2016-07-12T16:00:00-04:00","event_time_end_last":"2016-07-12T16:00:00-04:00","gmt_time_start":"2016-07-12 18:00:00","gmt_time_end":"2016-07-12 20:00:00","gmt_time_end_last":"2016-07-12 20:00:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"100811","name":"Phd Defense"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}