In partial fulfillment of the requirements for the degree of
Doctor of Philosophy in Biology
In the
School of Biological Sciences
Kathleen O’Connor
Will defend her dissertation
Quorum Sensing Cooperation and Conflict in Pseudomonas aeruginosa
Friday October 13th, 2023
10 AM
EBB 3029
https://gatech.zoom.us/j/94511427667?pwd=SlZEY0ovQkUzL0VJdlpmRzRPT0grdz09
Thesis Advisor:
Stephen P. Diggle, Ph.D.
School of Biological Sciences
Georgia Institute of Technology
Committee Members:
Marvin Whiteley, PhD
School of Biological Sciences
Georgia Institute of Technology
Sam Brown, Ph.D.
School of Biological Sciences
Georgia Institute of Technology
Kendra Rumbaugh, PhD
Department of Surgery
Texas Tech University
Joanna Goldberg, PhD
Department of Pediatrics
Emory University School of Medicine
ABSTRACT: Bacteria are single celled organisms capable of making great changes to their environment. They accomplish this by working together – using social behaviors to collectively affect the world they live in. Bacterial cells are capable of both cooperation and conflict, flip sides of social behaviors that either benefit or harm the overall population. Social behaviors can only be maintained when the trait benefits both producing cells and closely-related neighbors, and are not overly costly to fitness. The social evolution in microbes field was born from looking at intra-species Pseudomonas aeruginosa social behaviors in liquid media, studying theory established by evolutionary biologists and economists and applying it to real organisms. Social studies in bacteria have now expanded to inter-species and even inter-kingdom social interactions. The field has also begun studying the importance of spatial structure for social traits, and it has been suggested that proximity is essential for social interactions in microbes. In this thesis, I focus on the social behavior quorum sensing (QS) in P. aeruginosa. I first investigate the variation in phenotypic and genotypic QS traits in P. aeruginosa across different environments, and then I study the impact of spatial structure and proximity on QS-regulated cooperation and spite.