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.