Dr. Paul Veith
Telephone: +61 3 8344 2561
- BSc (Hons): University of Melbourne, School of Biochemistry
- PhD: University of Melbourne, Melbourne Dental School
Protein secretion in pathogenic bacteria
Chronic periodontitis (gum disease) is associated with specific bacterial pathogens such as Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. P. gingivalis is the most important of these and produces large quantities of proteases (called gingipains) that are essential for the ability of this pathogen to cause disease. Our recent data indicates that these gingipains are located on the outside of the cell within a special surface layer that can be seen by electron microscopy (EM). We are intensively studying the secretion system responsible for transporting these gingipains across the outer membrane and incorporating them into this surface layer. This secretion system is newly discovered and seems to be conserved in the bacteroidetes phylum and therefore linked to a variety of diseases and environmental issues. We use a range of techniques including mass spectrometry, EM, cell fractionation, native and 2D electrophoresis, protein expression, mutant generation, bioinformatics, etc in order to identify the components of this novel secretion system and to determine the role of each component in the secretion mechanism. Please refer to Chen et al., 2011 (below) as a sample of our work in this exciting area.
Proteomics / Mass Spectrometry
We have our own well-established proteomics laboratory located in the Bio21 Institute that comprises MALDI-TOF/TOF and Ion Trap mass spectrometers, sample preparation robots, 2D electrophoresis equipment, fluorescent scanner, & in-house proteomics servers (Mascot, Proteinscape). Protein identification projects we have conducted include studies of all three periodontopathogens (Veith et al., 2002; Veith et al., 2009a; Veith et al., 2009b). Apart from having a high capability for all our protein identification needs, we have conducted several quantitative analyses in order to determine how P. gingivalis adapts to various growth conditions, such as iron (haem) limitation (Dashper et al., 2009), biofilm formation (Ang et al., 2008) and currently, the formation of synergistic biofilms with T. denticola and T. forsythia (see also Bacterial Ecology). The proteins that have changed in abundance reveal potential nutritional synergies and other fascinating adaptions to growth in this polymicrobial biofilm.
The oral cavity is home to many hundreds of bacterial species in both health and disease. The transition from health to disease may in many cases be due to a perturbation in the balance of these species, therefore the study of how these species interrelate may provide substantial insight into the species and conditions that promote or inhibit the proliferation of pathogens, and therefore the onset of disease. We have developed fermentors that allow the growth of polymicrobial biofilms, as well as tools to quantitate the various species present, analyse the composition and structure of the biofilm formed (by both confocal laser scanning microscopy and various EM techniques), and quantitate the proteins produced. This is a new area that promises to deliver fascinating insights into the spatial and temporal developments of polymicrobial communities relevant to oral diseases, and to learn how to favour the non-pathogenic organisms and inhibit the pathogenic ones.
CURRENT RESEARCH PROJECTS
A range of projects within the broad topics above can be tailored to suit prospective Honours, Masters, or PhD students. Please contact me to discuss your interests.
- See Dr. Veith's Find an Expert page at The University of Melbourne.