Date of Award

Fall 7-31-2023

Degree Type


Degree Name

Master of Science in Integrative Biology (MSIB)



Major Professor

Dr. Ramya Rajagopalan

First Committee Member

Dr. Ramya Rajagopalan

Second Committee Member

Dr. Anton Bryantsev

Third Committee Member

Dr. Melanie Griffin

Fourth Committee Member

Dr. Nick Green


Micropredators are a significant selective force driving the evolution of bacteria including human pathogens. Virulence factors and antibiotic resistance may have originated as a stress response mechanism for avoiding predators. Myxococcus xanthus is a micropredator for a wide variety of bacteria including clinically relevant human pathogens. We have tested the predatory ability of a laboratory reference strain of M. xanthus DK1622 against P. aeruginosa strain PAO1. We have found that live cells persist despite predation. The present study employs multi-sample time-lapse confocal microscopy to provide a clearer picture of this unique resistance response. Mixed cell assays showed statistically significant rejection of live prey and an increase in dead prey at the cellular level. Timelapse videos showed that ripple formation is inhibited at 48 hours. “Fold” deficient P. aeruginosa PAO1 strains clarified that M. xanthus is responsible for the appearance of the fold by showing complete blockage of M. xanthus motility after 48hr. Z-stacks revealed P. aeruginosa PAO1, and subtypes impede M. xanthus motility and form layers of M. xanthus atop P. aeruginosa PAO1 with smaller waves embedded in the prey spot at the site of the “fold”.

Available for download on Saturday, July 29, 2028