How to Beat Diffusion: Explorations of Energetics and Spatial Relationships in Microbial Ecosystems

• Main Author: Chadwick, Grayson Lee
• Format: Others
• Language: en; en
• Published: 2021
• Online Access: https://thesis.library.caltech.edu/13842/37/Chadwick_Thesis_v3.pdf; https://thesis.library.caltech.edu/13842/36/Chapter_4_supplemental_videos.zip; Chadwick, Grayson Lee (2021) How to Beat Diffusion: Explorations of Energetics and Spatial Relationships in Microbial Ecosystems. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/svrp-rb07. https://resolver.caltech.edu/CaltechTHESIS:07182020-211405749 <https://resolver.caltech.edu/CaltechTHESIS:07182020-211405749>

<p>This thesis investigates four microbial systems, with a particular focus for how spatial considerations shape the behavior and evolution of microorganisms. After a general introduction in Chapter 1, Chapter 2 presents the results of experiments demonstrating how cellular activity varies through space within an anode-reducing biofilm. Chapter 3 presents a comprehensive comparative genomic analysis of all known marine anaerobic methanotrophic archaea, supporting the notion that these organisms share many energetic similarities with the anode reducing organisms in Chapter 2. These are interpreted as specific adaptations to life in highly structured microbial communities. Chapter 4 describes the enrichment and characterization of a new member of the purple sulfur bacteria, and the adaptations that may improve substrate acquisition beyond the normal limitations of diffusion. Chapter 5 describes the convergent evolution of novel Complex I gene clusters that have incorporated new proton pumping subunits, and the modifications made to the protein structure to facilitate the incorporation of these new subunits into the quaternary structure of the complex.</p>