Chemical, Physiological and Metabolic Interactions between Pseudomonas, Metals and Environmental Nutrients
Abstract
Environmental pollution is one of the major problems facing humanity. Bacteria are capable of removing pollutants from the environment through their metabolic activities. This works for organic pollutants, but metals inhibit the degradation process. Pseudomonas pseudoalcaligenes KF707 is a bacterium that is resistant to metals and is able to degrade pollutants such as polychlorinated biphenyls. In this thesis I present how interactions between the bacterium, its environment and metals affect the bacterium’s physiology and metabolism of biphenyl. Chemical interactions with environmental components affect the toxicity of metals towards bacteria. By examining the tolerance of Pseudomonas species towards copper and aluminium in different media compositions I found that metal bioavailability and carbon source quality had a strong influence on the amount of metal they could withstand. Building on these data, I used metabolomics to understand how metals interfere with organic pollutant degradation. By quantifying the small molecules used and produced by the bacterial cell I was able to determine that metal toxicity is exacerbated by the oxidative stress of metabolizing an organic pollutant. P. pseudoalcaligenes KF707 can swim towards biphenyl but it was unknown how. By deleting genes that were expected to be involved in energy-taxis, a process that allows bacteria to swim to metabolizable carbon sources, I found that this was not how KF707 swims towards biphenyl. I did discover that some unexpected genes were involved in energy-taxis and also that the primary gene for this behavior, Aer, is actually a family of receptors with variable phylogenetic distribution in the genus Pseudomonas. These results provide new insight into the interactions between a bacterium and the nutrients and stressors in their environment.
Description
Keywords
Microbiology
Citation
Booth, S. C. (2017). Chemical, Physiological and Metabolic Interactions between Pseudomonas, Metals and Environmental Nutrients (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/25315