{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/105580"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/105580","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Higher-order interaction inhibits bacterial invasion of a phototroph-predator microbial community","abstract":"The composition of an ecosystem is thought to be important for determining its resistance to invasion. Studies of natural ecosystems, from plant to microbial communities, have found that more diverse communities are more resistant to invasion. It is thought that more diverse communities resist invasion by more completely consuming the resources necessary for invaders. Here we show that Escherichia coli can successfully invade cultures of the alga Chlamydomonas reinhardtii (phototroph) or the ciliate Tetrahymena thermophila (predator), but cannot invade a community where both are present. The invasion resistance of the algae-ciliate community arises from a higher-order (3-way) interaction that is unrelated to resource consumption. We show that the mechanism of this interaction is the algal inhibition of bacterial aggregation which leaves bacteria vulnerable to ciliate predation. This mechanism requires both the algae and the ciliate to be present and provides an example of invasion resistance through a trait-mediated higher-order interaction. In a separate project we explore how the environment determines evolutionary trajectory when there exists a trade-off between beneficial traits. We select Escherichia coli for faster migration through a porous environment, a process which depends on both motility and growth. Evolving faster migration in rich medium results in slow growth and fast swimming, while evolution in minimal medium results in fast growth and slow swimming. Given that both fast growth and fast swimming would enhance migration rate, this result suggests that there is a trade-off between these two phenotypes and that the direction of evolution depends on the environment.","abstract_html":"The composition of an ecosystem is thought to be important for determining its resistance to invasion. Studies of natural ecosystems, from plant to microbial communities, have found that more diverse communities are more resistant to invasion. It is thought that more diverse communities resist invasion by more completely consuming the resources necessary for invaders. Here we show that Escherichia coli can successfully invade cultures of the alga Chlamydomonas reinhardtii (phototroph) or the ciliate Tetrahymena thermophila (predator), but cannot invade a community where both are present. The invasion resistance of the algae-ciliate community arises from a higher-order (3-way) interaction that is unrelated to resource consumption. We show that the mechanism of this interaction is the algal inhibition of bacterial aggregation which leaves bacteria vulnerable to ciliate predation. This mechanism requires both the algae and the ciliate to be present and provides an example of invasion resistance through a trait-mediated higher-order interaction. In a separate project we explore how the environment determines evolutionary trajectory when there exists a trade-off between beneficial traits. We select Escherichia coli for faster migration through a porous environment, a process which depends on both motility and growth. Evolving faster migration in rich medium results in slow growth and fast swimming, while evolution in minimal medium results in fast growth and slow swimming. Given that both fast growth and fast swimming would enhance migration rate, this result suggests that there is a trade-off between these two phenotypes and that the direction of evolution depends on the environment.","abstract_has_math":false,"creators":["Mickalide, Harry"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Kuehn, Seppe","Chemla, Yann","Dahmen, Karin","O'Dwyer, James"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019-11-26T20:33:32Z","date_published":"2019-11-26T20:33:32Z","updated_at":"2026-07-22T22:24:44Z","subjects":["ecology","microbialecology","bacteria","algae","invasionecology","physics","biophysics","microbialbiology"],"languages":["en"],"rights":["Images and text may be modified and reused as long as original author is credited."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/105580","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Kuehn, Seppe","Chemla, Yann","Dahmen, Karin","O'Dwyer, James"]},{"key":"dc:creator","label":"Author","values":["Mickalide, Harry"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2019-11-26T20:33:32Z","2019-05-22","2019-08"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["ecology","microbialecology","bacteria","algae","invasionecology","physics","biophysics","microbialbiology"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Images and text may be modified and reused as long as original author is credited."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/105580"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The composition of an ecosystem is thought to be important for determining its resistance to invasion. Studies of natural ecosystems, from plant to microbial communities, have found that more diverse communities are more resistant to invasion. It is thought that more diverse communities resist invasion by more completely consuming the resources necessary for invaders. Here we show that Escherichia coli can successfully invade cultures of the alga Chlamydomonas reinhardtii (phototroph) or the ciliate Tetrahymena thermophila (predator), but cannot invade a community where both are present. The invasion resistance of the algae-ciliate community arises from a higher-order (3-way) interaction that is unrelated to resource consumption. We show that the mechanism of this interaction is the algal inhibition of bacterial aggregation which leaves bacteria vulnerable to ciliate predation. This mechanism requires both the algae and the ciliate to be present and provides an example of invasion resistance through a trait-mediated higher-order interaction. In a separate project we explore how the environment determines evolutionary trajectory when there exists a trade-off between beneficial traits. We select Escherichia coli for faster migration through a porous environment, a process which depends on both motility and growth. Evolving faster migration in rich medium results in slow growth and fast swimming, while evolution in minimal medium results in fast growth and slow swimming. Given that both fast growth and fast swimming would enhance migration rate, this result suggests that there is a trade-off between these two phenotypes and that the direction of evolution depends on the environment.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2019-11-26 without embargo terms","The student, Harry Mickalide, accepted the attached license on 2019-05-21 at 13:12.","The student, Harry Mickalide, submitted this Dissertation for approval on 2019-05-21 at 13:20.","This Dissertation was approved for publication on 2019-05-22 at 16:28.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13985 on 2019-11-26 at 12:48:57","Made available in DSpace on 2019-11-26T20:33:32Z (GMT). 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It is thought that more diverse communities resist invasion by more completely consuming the resources necessary for invaders. Here we show that Escherichia coli can successfully invade cultures of the alga Chlamydomonas reinhardtii (phototroph) or the ciliate Tetrahymena thermophila (predator), but cannot invade a community where both are present. The invasion resistance of the algae-ciliate community arises from a higher-order (3-way) interaction that is unrelated to resource consumption. We show that the mechanism of this interaction is the algal inhibition of bacterial aggregation which leaves bacteria vulnerable to ciliate predation. This mechanism requires both the algae and the ciliate to be present and provides an example of invasion resistance through a trait-mediated higher-order interaction. In a separate project we explore how the environment determines evolutionary trajectory when there exists a trade-off between beneficial traits. We select Escherichia coli for faster migration through a porous environment, a process which depends on both motility and growth. Evolving faster migration in rich medium results in slow growth and fast swimming, while evolution in minimal medium results in fast growth and slow swimming. Given that both fast growth and fast swimming would enhance migration rate, this result suggests that there is a trade-off between these two phenotypes and that the direction of evolution depends on the environment.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2019-11-26 without embargo terms","The student, Harry Mickalide, accepted the attached license on 2019-05-21 at 13:12.","The student, Harry Mickalide, submitted this Dissertation for approval on 2019-05-21 at 13:20.","This Dissertation was approved for publication on 2019-05-22 at 16:28.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13985 on 2019-11-26 at 12:48:57","Made available in DSpace on 2019-11-26T20:33:32Z (GMT). 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