Bacteria at interfaces: dissecting the mechanisms of bacteria attachment and growth on surfaces
Final Report Abstract
The research proposal focused on fundamental questions of bacterial adhesion, behaviour, and physiology: specifically, how bacteria sense, and respond to surfaces, and more broadly, to their physical extracellular environment. The mechanisms that underlie interfacial phenomena of bacteria - for example, adhesion, swarming motility (cooperative movement of communities on surfaces), and biofilm formation - are still poorly understood. To study these phenomena, I proposed to combine techniques of surface engineering–by synthesising alternative defined substrate surfaces–and materials science with microbiology and genetics to analyse the behaviour of bacterial cells on surfaces. We introduced polyacrylamide substrates as an alternative (but not replacement) to agar for microbial cell culture and studies. Over the last 130 years, agar has been the central material used for microbial culture and isolation. However, a lack of control over the chemical and physical properties of agar limits its application in probing the interactions between bacteria and surfaces. We found that several bacterial strains can be grown on polyacrylamide surfaces. The swarming motility of Proteus mirabilis depended on the physico-chemical properties of the monomer unit. The addition of polyacrylamide to the suite of microbiological techniques and materials for culturing and studying microorganisms can complement agar and other microbiological reagents. The chemically and physically defined features of polyacrylamide may enable studies of microorganisms in conditions that more closely mimic their native environment. We further studied the surface motility (swarming) of Proteus mirabilis with biochemistry and molecular biology tools. The swarmer type is characterised by hyper flagellation that increases the motility significantly. This genetic control may be relevant for the adaptation of the pathogen during host invasion, its evasion to the host immune response and the cause for urinary tract infections. The exploration of the research topic contributed to the understanding of the relationship between surface properties and bacteria. Future work will be directed in the understanding of specific bacteria-host signal interactions by customising substrate surfaces to gain deeper knowledge of pathogen attachment and invasion. A mechanistic understanding of the stimuli and parameters that play a role in bacteria sensing surface, interfaces, and other cells in communities will provide innovative strategies to control bacteria-surface interactions and new methods and materials for the management and prevention of infections and biofilm formation.
Publications
- Physicochemical regulation of biofilm formation. MRS Bulletin, 2011, 36, 347-355
L.D. Renner, D.B. Weibel
- Polyacrylamide hydrogels as substrates for studying bacteria. Chem. Commun. 2012, 48, 1595-159
H.H. Tuson, L.D. Renner, D.B. Weibel
