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Causes And Consequences Of Lasr Mutant Selection In Pseudomonas Aeruginosa Populations, Dallas L. Mould May 2023

Causes And Consequences Of Lasr Mutant Selection In Pseudomonas Aeruginosa Populations, Dallas L. Mould

Dartmouth College Ph.D Dissertations

Change is the only constant in life, and these changes, though random in nature, can have consequences. Quorum sensing is heterogeneous in phenotype and prone to negative selection. In P. aeruginosa, the regulator LasR is frequently non-functional in phylogenetically diverse isolates. Through repeated experimental evolution and mathematical modeling, we show that differences in growth enable lasR mutant evolutionary success and this requires a system enabling metabolic choices, known as carbon catabolite repression (or catabolite repression). The differences in catabolite repression between wild type and lasR mutants enable altered metabolite preferences, and the resulting differences in metabolic states enable intraspecies …


Quorum Sensing Signals Produced By Heterotrophic Bacteria In Black Band Disease (Bbd) Of Corals And Their Potential Role In Bbd Pathogenesis, Chinmayee D. Bhedi Jun 2017

Quorum Sensing Signals Produced By Heterotrophic Bacteria In Black Band Disease (Bbd) Of Corals And Their Potential Role In Bbd Pathogenesis, Chinmayee D. Bhedi

FIU Electronic Theses and Dissertations

Black band disease (BBD) of corals is a temperature dependent, highly virulent, polymicrobial disease affecting reef-building corals globally. The microbial consortium of BBD is primarily comprised of functional physiological groups that include photosynthetic cyanobacteria, sulfate reducers, sulfide oxidizers and a vast repertoire of heterotrophic bacteria. Quorum sensing (QS), the cell-density dependent communication phenomenon in bacteria, is known to induce expression of genes for a variety of virulence factors in diseases worldwide. Microbes capable of QS release signals such as acyl homoserine lactones (AHLs) and autoinducer-2 (AI-2), which coordinate microbial interaction. The focus of the present study was to investigate the …