Please use this identifier to cite or link to this item:
http://arks.princeton.edu/ark:/88435/dsp01j6731714g
Title: | Mechanics and Motility of Myxococcus xanthus |
Authors: | Black, Matthew Edward |
Advisors: | Shaevitz, Joshua W |
Contributors: | Quantitative Computational Biology Department |
Subjects: | Biophysics Microbiology |
Issue Date: | 2024 |
Publisher: | Princeton, NJ : Princeton University |
Abstract: | Emergent phenomena pervade the biological world. These phenomena come about due to interactions between the constituent units of a larger whole in contexts ranging from cells within a developing embryo or tissue, to groups of social organisms living together. In this thesis, we use the model bacteria Myxococcus xanthus (M. xanthus) to investigate two varieties of such phenomena. Unlike most bacteria, the life cycle of M. xanthus is predicated upon the population being maintained in a swarm-like state of high cell density. To ensure that such a state is maintained, populations of M. xanthus employ a variety of collective behaviors both vegetatively, where they leverage their swarming state to more efficiently predate other microorganisms, and under starvation whereupon the population undergoes a primitive developmental process and self-assembles into a macroscopic, spore-filled fruiting body.First, we use atomic force microscopy to probe the rheological properties of these fruiting bodies. By doing so throughout the developmental process, we map out how the mechanical properties of these structures evolve as they grow. Altogether, these results suggest that the continuum, many-bacteria scale mechanics of fruiting bodies evolve over the course of development towards the fulfillment of the fruiting bodies ultimate purpose in preserving the population as a coherent whole against prolonged environmental stress. Next, we investigate the effect of fluid wetting on the dynamics of terrestrial bacteria. Such wetting occurs when solid objects are placed on top of a (semi-)hydrated surface and thus is likely ubiquitous in the soil where M. xanthus lives. We show that the interaction of wetting menisci of adjacent cells creates an attractive capillary force between cells. We present evidence that these forces can explain the dynamics of motile cells wherein different emergent patterns can form based solely on the interaction of capillary forces with the frequency with which such cells reverse their direction of motion. Comparison with the solitary gliding bacteria Flavobacteria johnsoniae suggest that the emergent behaviors demonstrated by our model are general to all gliding bacteria and may be used as a minimal framework for reasoning about such populations. |
URI: | http://arks.princeton.edu/ark:/88435/dsp01j6731714g |
Type of Material: | Academic dissertations (Ph.D.) |
Language: | en |
Appears in Collections: | Quantitative Computational Biology |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
Black_princeton_0181D_14973.pdf | 22.25 MB | Adobe PDF | View/Download |
Items in Dataspace are protected by copyright, with all rights reserved, unless otherwise indicated.