Biology & Marine Biology

Faculty & Staff

Ryan G. Rhodes, Lecturer

RhodesPh.D., Cell and Molecular Biology, The University of Rhode Island, Kingston, RI, 2009
M.S., Biology, Edinboro University of Pennsylvania, Edinboro, PA, 2000
B.S., Biology, Ursinus College, Collegeville, PA, 1997
Friday Hall 2024A | (910) 962-2208 | 601 South College Road, Wilmington, NC 28403-5915 |

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

Gliding Motility

For motility studies 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. As an example, one of the 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 this adhesin is 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. Current research on gliding motility is focused on:

  • Identifying redundant cell surface proteins involved in gliding motility and adhesion
  • Investigating the signal sequence predicted to direct cell surface proteins to the secretion machinery
  • Developing a chemotaxis assay to identify novel chemotaxis genes in F. johnsoniae.

Bacterial Pathogenesis

In addition to motility, my lab is also interested in the mechanisms that bacterial pathogens use to cause disease. Work is currently focused on adapting the genetic techniques used for manipulating F. johnsoniae to the fish pathogens F. columnare and F. psychrophilum. Both of these organisms cause significant losses in the aquaculture industry each year, and development of new genetic techniques will allow us to knock-out target genes and evaluate their role in the disease process. Information gathered from these studies will provide a better understanding of the pathogenesis of these organisms and will help identify possible vaccine candidates. Current research on bacterial pathogenesis is focused on:

  • Developing an allelic exchange system in F. columnare and F. psychrophilum.
  • Knocking-out genes that are predicted to be involved in virulence.
  • Evaluating virulence of gene deletion mutants in fish models.


Shrivastava A., R.G. Rhodes, S. Pochiraju, D. Nakane and M.J. McBride. 2012. Flavobacterium johnsoniae RemA is a mobile cell surface lectin involved in gliding. J Bacteriol. 194(14):3678-3688.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.