{"596935":{"#nid":"596935","#data":{"type":"event","title":"Collapse of Genetic Division of Labor and Evolution of Autonomy in Pellicle Biofilms","body":[{"value":"\u003Cp\u003E\u003Cstrong\u003E\u0026Aacute;kos T. Kov\u0026aacute;cs\u003Cbr \/\u003E\r\nProfessor of Bacterial Physiology and Genetics\u003Cbr \/\u003E\r\nTechnical University of Denmark\u003Cbr \/\u003E\r\nDepartment of Biotechnology and Biomedicine\u003Cbr \/\u003E\r\nBacterial Interactions and Evolution Group\u003C\/strong\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cbr \/\u003E\r\n\u003Cstrong\u003EAbstract\u003C\/strong\u003E\u003Cbr \/\u003E\r\nClosely related microbes often cooperate, but prevalence and stability of cooperation between different genotypes remains debatable. Here, we explore the long term evolutionary dynamics of biofilms formed through genetic division of labor.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EPellicle biofilms of \u003Cem\u003EBacillus subtilis\u003C\/em\u003E form at liquid-air interface where bacteria stick to each other encased in an extracellular matrix (ECM) composed of exopolysaccharide EPS and fiber protein TasA. Failure to synthesize EPS or TasA prevents pellicle formation however \u2206\u003Cem\u003Eeps\u003C\/em\u003E and \u2206\u003Cem\u003EtasA \u003C\/em\u003Ecan complement each other and form robust pellicle. We compared the evolution of these mutants under two alternative conditions: in mixed cultures with constrained division of labor and in monocultures where both strains perform poorly at the beginning due to the lack of either EPS or TasA.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EAfter over 200 generations of experimental evolution, both monoculture mutants evolved autonomous pellicles pursuing two distinct evolutionary trajectories. The molecular adaptation of \u2206\u003Cem\u003Etas\u003C\/em\u003E took part through several alternative paths that all led to increased levels of EPS secretion and development of slimy pellicles that were less stiff and more viscous as compared to the wild type. On the contrary, two of six \u2206\u003Cem\u003Eeps\u003C\/em\u003E populations evolved interface colonization via distinct substitutions in TasA-encoding gene presumably altering the biochemical properties of TasA. Interestingly, while the ECM of evolved \u2206\u003Cem\u003EtasA\u003C\/em\u003E could be easily exploited by the non-evolved strain, the ECM of evolved \u2206\u003Cem\u003Eeps\u003C\/em\u003E was highly privatized. In co-cultures, the \u2206\u003Cem\u003EtasA\u003C\/em\u003E gradually outcompeted its partner in each parallel mixed population leading to rapid biofilm collapse and dramatic productivity loss, however, after the exclusion of \u2206\u003Cem\u003Eeps\u003C\/em\u003E the \u2206\u003Cem\u003EtasA\u003C\/em\u003E pursued a similar adaptive path as in monocultures.\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EDespite the short-term success, genetic division of labor in biofilm formation collapsed and slowed down the evolution of autonomy of the winning partner. The loss of \u2206\u003Cem\u003Eeps\u003C\/em\u003E in the mix and its lower chance for autonomy evolution may indicate evolutionary trade-offs linked to privatization of public goods. Differences in dependency levels and availability of public goods exchanged by the cooperating partners likely contributed to cooperation collapse revealing a barrier against evolution of intraspecific cooperation in microbes.\u003C\/p\u003E\r\n","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"A Seminar by \u00c1kos T. Kov\u00e1cs, Professor of Bacterial Physiology and Genetics at the Technical University of Denmark"}],"uid":"27964","created_gmt":"2017-10-04 16:21:08","changed_gmt":"2017-10-04 16:21:08","author":"Jasmine Martin","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2017-10-20T12:00:00-04:00","event_time_end":"2017-10-20T12:00:00-04:00","event_time_end_last":"2017-10-20T12:00:00-04:00","gmt_time_start":"2017-10-20 16:00:00","gmt_time_end":"2017-10-20 16:00:00","gmt_time_end_last":"2017-10-20 16:00:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"groups":[{"id":"1275","name":"School of Biological Sciences"}],"categories":[],"keywords":[{"id":"166882","name":"School of Biological Sciences"},{"id":"168156","name":"Steve Diggle"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1795","name":"Seminar\/Lecture\/Colloquium"}],"invited_audience":[{"id":"78761","name":"Faculty\/Staff"},{"id":"78771","name":"Public"},{"id":"174045","name":"Graduate students"},{"id":"78751","name":"Undergraduate students"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Ca href=\u0022mailto:steve.diggle@biosci.gatech.edu\u0022\u003ESteve Diggle\u003C\/a\u003E\u003C\/p\u003E\r\n","format":"limited_html"}],"email":[],"slides":[],"orientation":[],"userdata":""}}}