Date of Award


Degree Type


Degree Name

Master of Science (MS)


Microbiology and Immunology


Pseudomonas aeruginosa is a gram-negative, opportunistic pathogen that is ubiquitous in nature, especially in human/animal impacted environments. One of the reasons for this is the arsenal of protein systems and toxins that P. aeruginosa utilizes to mold its environment to suit its needs. Recently, we discovered a novel locus in the P. aeruginosa genome, which resembles other loci that are known to mediate interbacterial competition. Our bioinformatic analysis found this locus to be enriched in a rearrangement hotspot (rhs) motif which led us to ad-interim term the three ORFs of the loci as rhsB, rhsC, and rhsI. Furthermore, we have noted variability in the 5’ end of rhsB, and the 3’ end of rhsC with a concomitant change in rhsI across all strains of P. aeruginosa. Altogether, we hypothesize that the 3’ end of rhsC and rhsI encode toxin/immunity pairs that mediate interbacterial competition while the 5’ end of rhsB provides target specificity.In this thesis we utilized biochemical approaches to investigate the physical interactions between the putative RhsC-toxins and their immunity factors. As we performed Co-IPs and protein purifications, we found that the putative RhsC-toxins are bound by their putative immunity factors. This suggests that the neutralization of the toxins effect may occur through the binding of the immunity factor to the toxin. During our studies, we also developed protocols that improved the detection of toxins and allow for the purification of the various toxins and immunity proteins.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

Available for download on Friday, August 16, 2024

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