IPLS/BioP Seminar - Prof. Jamie Hobbs (University of Sheffield)

Bacteria have a cross-linked macromolecular envelope or "wall" which is essential for cell viability, maintaining cell turgor and acting as a mechanical barrier. Although the biochemistry of the cell wall is well documented, with the primary structural component being peptidoglycan, its organisation and architecture is less well understood. The manner of its synthesis, and how cells are able to grow and divide while maintaining the physiologically required turgor pressure, is also an area of active research. Here atomic force microscopy is used to reveal in unprecedented detail the molecular organisation of the cell wall in model Gram negative (E. coli) and Gram positive (S. aureus, B. subtilis) organisms. By combining in situ observation of live bacteria with imaging of extracted cell walls that allow both internal and external surfaces to be examined, new insights are obtained into how cells grow, how the wall behaves as a barrier and as a mechanical structure, as well how the wall evolves through the cell cycle. Aspects of the AFM instrumentation that enable these experiments will also be discussed.