The research focus of my laboratory has grown to include a number of basic research themes, which have been developed into a series of applied research projects. Basic research problems have included: the role of lectins at mucosal surfaces in regulating and organizing complex carbohydrate secretions at the mucosal surface, how the loss of mucosal integrity can lead to inflammatory and infectious diseases at mucosal surfaces, and finally the use of forensic techniques in the field of archaeology.
BASIC RESEARCH: There are a number of ongoing research projects in my laboratory which students may undertake at both the graduate and undergraduate (CMMB 530/528, CMMB 507) levels.
1. Lectins in mucosal integrity: The class of lectins we study are secreted proteins which bind carbohydrate ligands found on both cell surfaces and on extracellular complex carbohydrate secretions such as mucins and glycosaminoglycans (GAGS). These complex carbohydrate secretions represent the only barrier between the outside world and the mucosal surfaces of the respiratory, gastrointestinal, and urogenital tracts, and the eye. Maintaining the continuity of this layer is fundamental to good health. Loss of integrity can lead to inflammatory and infectious diseases. We have developed 2 model systems to look at the roles of lectins in mucosal integrity and disease.
The quail model was developed because the avian intestine has but one lectin, compared to the many found in the mammalian gut. We have localized the lectin to intestinal goblet cells from which it is co-secreted with mucin. We have demonstrated that mucin and lectin secretion in the intestinal crypts is under cholinergic regulation via both calcium and Protein Kinase C (PKC) regulation. We have also shown that inhibiting lectin binding to the mucosal surface increases mucin secretion in a PKC independent mechanism, while the saturation of lectin binding sites inhibits mucin secretion. We have demonstrated specific lectin receptors to be present on brush-border membranes formed from quail intestine. Our future goals are; to isolate the mucosal surface receptors of the intestinal lectin, to identify the signal transduction pathway by which lectin serves as a fine control for mucin secretion, and to investigate ways of regulating mucin secretion as a possible mechanism of treating inflammatory mucosal disease.
We have demonstrated that mucin and lectin, expressed at the mucosal surface of normal prostatic acini, is lost very early in the development of benign hyperplasia of the prostate. These changes to the protective layer of the prostate acini may contribute to both bacterial and non-bacterial prostatitis in aging men. We have established rat models for bacterial and abacterial prostatitis and have examined the role of the immune system in protecting the prostate from infection. We have also looked at the importance of bacterial lectins as virulence factors in causing prostatitis and at the role of Cytotoxic Necrotizing factor Type 1 (CNF-1) and other virulence factors have on the nature of inflammation seen in prostatitis. We have also followed the cytokine response to both bacterial and abacterial prostatitis. We have also demonstrated the presence of proteases activated receptors 1 and 2 (PAR-1 and PAR-2) in the rat prostate and are studying the role of these G-protein coupled signal systems in regulating inflammation of the prostate.
2. Biofilm development: We are interested in the formation of biofilms and altered gene expression that accompanies the change in growth form, seen in bacterial, fungal, and mycobacteria biofilm formation. We have developed a new technology for growing multiple biofilms, which makes the study of biofilm development and gene expression a more easily addressed question. We study both mono-culture and mixed species biofilms to better understand the interaction between members of the biofilm community. Biofilms may be either positive associations, as in fermentation systems and bioremediation, or negative associations, as in antibiotic resistant colonies on implanted materials and on mucosal surfaces of the body or causing corrosion of pipelines. A better understanding of biofilm "life" may allow us to develop better ways to encourage biofilm formation, when wanted, or to treat biofilm problems when they exist.
3. Molecular Archaeology: With Dr. Margaret Newman (PhD Archaeology) my lab has been involved in developing molecular approaches to the study of Archaeological artifacts. We have used immunological and molecular biology approaches to study protein and DNA left behind on tools, weapons, cooking utensils, etc. to study past life styles.
APPLIED RESEARCH: A number of applied research projects on ongoing in my laboratory, most of which are being carried out as part of the Biofilm Research Group, here at the University of Calgary.
1. Giardiasis Vaccine:Giardia lamblia is the leading protozoan cause of diarrhea in man. This zoonotic infection (also known as Beaver Fever), can infect many animals including dogs and cats. Studies of pet populations in many of the major cities of the world have shown that Giardia is carried by 8-20% of the dogs and cats, based on a single assay sample. As cysts are spread intermittently this is very much an underestimate of infection rates. In collaboration with Drs. M.E. Olson and D.W. Morck a vaccine against Giardiasis has been developed for dogs and cats. The vaccine is now available in canada and the USA. The vaccine will not only protect our companion animals from infection, but will also reduce the reservoir for this disease in urban areas and hence lower the incidence of Giardiasis in man. Giardia is the leading cause of diarrhea in Toronto day care settings. We have also demonstrated that Giardia infection inhibits weight gain in ruminants, and that virtually 100% of calves and lambs in Alberta are infected with Giardia . We are currently developing a large animal vaccine, with vaccine trials to be carried out in the near future.
2. Lectin Markers in Prostate Cancer: Our studies of lectin distribution in benign hyperplasia of the prostate have revealed a change of a lectin distribution pattern in prostate cancer. Cancer in the stromal tissue is accompanied by the specific expression of a lectin not seen in the stromal tissues of normal prostates or in sections of benign prostatic hyperplasia.
3. Biofilm Research Group: As a member of the biofilm research group I have become involved in a number of research projects that are ongoing within the group. Of these many projects the ones that I am most directly involved as the leader of the research project are:
A New Means for Antibiotic Development.
Bacteria have been traditionally cultured in rich mediums, as free swimming (planktonic) organisms, at maximal growth rates. This has allowed for high yields of organisms on which to conduct experiments on microbial physiology. It is also under these growth conditions that antibiotics have been tested and selected. Therefore, in antibiotic development pharmaceutical companies have selected candidate antibiotics for their killing of planktonic bacteria. In hospital diagnostic labs the choice and concentration of antibiotic to be used for patient treatment have been based on the same criteria. The assay used in both cases is the minimal inhibitory concentration or MIC test. It is well established that MIC value and drug efficacy are not related. It is also well known that bacteria growing attached to surfaces encased in carbohydrate (bacterial biofilms) are inherently more resistant to antibiotics than the same organism as a planktonic organism.Attachment to surfaces is important to most bacterial infections, therefore it is important that antibiotics be evaluated on the basis of their interaction with biofilms. The Calgary Biofilm Device offers the first effective means to study the physiology, and antibiotic resistance of biofilm organisms.
We are interested in the eye as a model of mucosal surfaces, as noninvasive methods can be used to study the eye. We are currently mapping the lectin and mucin distribution of the eye and initiating studies of the effects of contact lens ware on mucosal integrity. We are looking at the effects of biofilm formation on lens materials, cleaning solutions, and lens storage devices on mucosal inflammation and mucosal integrity.
For a list of current publications.html click here.