Dissertation

Structural characterization of the cell envelope of Actinobacteria under changing environments

Bacteria have the ability to alter their morphology in order to adapt to changing environments.

Author: Ultee, E.
Date: 02 December 2020
Links: Thesis in Leiden Repository

Bacteria have the ability to alter their morphology in order to adapt to changing environments. We have investigated the role of the cell envelope in the development and stress-adaptation strategies of Actinobacteria. Here, we demonstrate how cryo-electron microscopy techniques can be used as efficient tools to study cell envelope of various bacteria. An in-depth study on the Streptomyces cell wall with cryo-electron tomography reveals the structural complexity of the Gram-positive cell wall in apically growing bacteria. Additionally, we report the formation of intracellular membrane accumulations in Streptomyces as a result of exposure to a stress-inducing agent. Furthermore, we studied the ability of the filamentous actinomycete Kitasatospora viridifaciens to extrude wall-deficient cells or S-cells upon exposure to hyperosmotic stress. We characterized the structural alterations associated with S-cell formation using cryo-electron microscopy and reveal that S-cell formation requires cytoskeletal protein FilP in K. viridifaciens. To summarize, this thesis provides new insights in the structural complexity and stress-induced alterations of the bacterial cell envelope.