Abstract

This talk will be split into three sections. In the first data will be presented using atomic force microscopy (AFM) to explore the mechanical properties of the cell wall of the gram positive bacteria Staphylococcus aureus through the cell cycle. S. aureus divides in an unusual way, in which new cell wall is only deposited in the septum that divides the two daughter cells, and subsequent growth occurs through the re-engineering of this material. New evidence that cell growth in fact occurs through degradation of the cell wall will be presented. Secondly, a new form of AFM , “torsional tapping AFM ” will be presented which allows imaging at true molecular resolution under ambient conditions. This new technique has been used to address some long standing questions in how synthetic polymers crystallize and in the nature of the crystal amorphous interface which is instrumental in giving many commodity polymers (such as plastic bags) their desirable mechanical properties. Finally, progress in using this technology to unravel the molecular architecture of bacterial envelopes, including the exosporium of the food pathogen Bacillus cereus, will be presented.