Rhodes, Ryan

Publications:  (An asterisk, *, indicates an undergraduate co-author.)

1. Rhodes, R.G., M.N. Samarasam, E.J. van Groll* and M.J. McBride. 2011. Mutations in Flavobacterium johnsoniae sprE result in defects in gliding motility and protein secretion. J. Bacteriol. 193(19):5322-5327.
2. Rhodes, R.G., H.G. Pucker* and M.J McBride. 2011. Development and use of a gene deletion strategy for Flavobacterium johnsoniae to identify the redundant gliding motility genes remF, remG, remH and remI. J. Bacteriol. 193(10):2418-2428.
3. Rhodes, R.G., S.S. Nelson, S. Pochiraju and M.J. McBride. 2011. Flavobacterium johnsoniae sprB is part of an operon spanning the additional gliding motility genes sprC, sprD and sprF. J. Bacteriol. 193(3):599-610.
4. Rhodes, R.G., J.A. Atoyan and D.R. Nelson. 2010. The chitobiose transporter, chbC, is required for chitin utilization in Borrelia burgdorferi. BMC Microbiol. 10:21.
5. Rhodes, R.G., M.N. Samarasam, A. Shrivastava, J.M. van Baaren, S. Pochiraju, S. Bollampalli and M.J. McBride. 2010. Flavobacterium johnsoniae gldN and gldO are partially redundant genes required for gliding motility and surface localization of SprB. J. Bacteriol. 192(5):1201-1211.
6. Sato, K., M. Naito, H. Yukitake, H. Hirakawa, M. Shoji, M.J. McBride, R.G. Rhodes and K. Nakayama. 2010. A protein secretion system linked to bacteroidete gliding motility and pathogenesis. Proc. Natl. Acad. Sci. USA. 107(1):276-281.
7. McBride, M.J., G. Xie, E.C. Martens, A. Lapidus, B. Henrissat, R.G. Rhodes, E. Goltsman, W. Wang, J. Xu, D.W. Hunnicutt, A.M. Staroscik, T.R. Hoover, Y.Q. Cheng and J.L Stein. 2009. Novel features of the polysaccharide-digesting gliding bacterium Flavobacterium johnsoniae as revealed by genome sequence analysis. Appl. Environ. Microbiol. 75(21):6864-6875.
8. Rhodes. R.G., W. Coy and D.R. Nelson. 2009. Chitobiose utilization in Borrelia burgdorferi is dually regulated by RpoD and RpoS. BMC Microbiol. 9:108.
9. Mamber, S.W., V. Long, R.G. Rhodes, S. Pond-Tor, L.R. Wheeler, K. Fredericks, B. Vanscoy, J.F. Sauniere, R. Steinschneider, J.C. Laurent and J. McMichael. 2004. The use of streptolysin O for the treatment of scars, adhesions and fibrosis: initial investigations using murine models of scleroderma. Nonlinearity Biol. Toxicol. Med. 2(2):67-87.
10. Pond-Tor, S., R.G. Rhodes, P.E. Dahlberg, J.T. Leith, J. McMichael and A.E. Dahlberg. 2002. Enhancement of radiosensitivity of the MCF-7 breast cancer cell line with human chorionic gonadotropin. Breast Cancer Res. Treat. 72(1):45-51.

Posters and Presentations: 

1. Rhodes, R.G., S. Nelson, S. Pochiraju and M.J. McBride. Flavobacterium johnsoniae sprB encodes a mobile cell-surface gliding protein and is part of an operon spanning five additional motility genes. Bacterial Locomotion and Signal Transduction XI. January 2011. New Orleans, LA.
2. McBride, M.J., R.G. Rhodes, S. Bollampalli and S. Pochiraju. Cell-surface proteins and polysaccharides involved in Flavobacterium johnsoniae gliding. Bacterial Locomotion and Signal Transduction XI. January 2011. New Orleans, LA.
3. Pochiraju, S., R.G. Rhodes, J. Liu and M.J. McBride. Role of cell-surface proteins in gliding motility of Flavobacterium johnsoniae. American Society for Microbiology: North Central Branch. October 2009. LaCrosse, WI.
4. Samarasam, M.N., E. VanGroll, R.G. Rhodes, S. Bollampalli and M.J. McBride. Mutations in Flavobacterium sprE result in defects in gliding motility. American Society for Microbiology: North Central Branch. October 2009. LaCrosse, WI.
5. Hunnicutt, D.W., G. Xie, A. Lapidus, E. Goltsman, W. Wang, J. Xu, B. Henrissat, E.C. Martens, A.M. Staroscik, Y. Yamada, R.G. Rhodes, T.R. Hoover, Y. Cheng and M.J. McBride. The complete genome sequence of Flavobacterium johnsoniae: novel features revealed by genome analysis. International Conference on Flavobacterium. September 2009. Paris, France.
6. McBride, M.J., R.G. Rhodes, S. Pochiraju, S. Bollampalli, A. Shrivastava, K. Sato, H. Yukitake, H. Hirakawa, M. Shoji and K. Nakayama. Novel motility and protein secretion machinery of Flavobacterium johnsoniae. International Conference on Flavobacterium. September 2009. Paris, France.
7. Rhodes, R.G., S.S. Nelson, S. Pochiraju and M.J. McBride. Flavobacterium johnsoniae sprB is part of a large operon spanning additional novel gliding motility genes. American Society for Microbiology General Meeting. May 2009. Philadelphia, PA.
8. Rhodes, R.G., J.A. Atoyan and D.R. Nelson. Adaptation to GlcNAc starvation in Borrelia burgdorferi is mediated by recA. American Society for Microbiology General Meeting. May 2008. Boston, MA.
9. Rhodes, R.G., W. Coy, and D.R. Nelson. Chitin utilization in Borrelia burgdorferi is regulated by RpoS. American Society for Microbiology General Meeting. May 2007. Toronto, Canada.
10. Rhodes, R.G., W. Coy, and D.R. Nelson. The alternative sigma factor RpoS regulates the utilization of chitobiose in Borrelia burgdorferi. Northeastern Microbiologists – Physiology, Ecology and Taxonomy. June 2006. Blue Mountain Lake, NY.

My research interests broadly encompass the molecular mechanisms underlying bacterial motility and pathogenesis, with a focus on the role that secretion plays in these processes.

Gliding Motility

My lab uses the model organism Flavobacterium johnsoniae to study bacterial gliding motility, a process by which cells crawl over solid surfaces such as agar and glass. The exact mechanism underlying gliding motility remains unknown; however, genome analyses suggest this type of cell movement does not involve well-studied structures such as flagella or pili that drive other types of bacterial locomotion. Recent work has demonstrated that the cell surface components of the machinery are partially redundant, and loss of one component does not result in a complete loss of motility. One of these cell surface components required for spreading on agar surfaces is the large (670 kDa) adhesin protein SprB. Colonies of SprB-deficient mutants do not spread on agar surfaces, but individual cells do exhibit some motility when observed in wet mount. In addition, it appears that these cell surface proteins are propelled along the cell surface, as latex spheres coated with anti-SprB antibody bind specifically to SprB on wild-type cells and are propelled rapidly around the cell surface.

Research on gliding motility in my lab is focused on:

1. Identifying redundant cell surface proteins involved in gliding motility.
2. Investigating the C-terminal signal sequence predicted to direct cell surface proteins to the newly described Por secretion system (PorSS).
3. Developing a chemotaxis assay to identify novel chemotaxis genes in F. johnsoniae.

Bacterial Pathogenesis 

Bacterial pathogenesis refers to the molecular mechanisms pathogens use to cause disease. Work in my lab is focused on the pathogenesis of the two Flavobacterium fish pathogens F. columnare and F. psychrophilum. Both of these organisms cause significant losses in the aquaculture industry each year. Students working on this project will have the opportunity to work with bacterial pathogens and learn about the mechanisms bacteria can use to cause disease. Information gathered from these studies will provide a better understanding of the pathogenesis of these organisms and help identify possible vaccine candidates.

Research on bacterial pathogenesis in my lab is focused on:

1. Developing a gene deletion system in F. columnare and F. psychrophilum.
2. Deleting genes in both organisms that are predicted to be involved in virulence.
3. Evaluating virulence of gene deletion mutants in fish models with collaborators at St. Norbert College in DePere, WI and at the College of Veterinary Medicine at Mississippi State University.