ARS | Publication request: Chemotaxis of Flavobacterium columnare: To Channel Catfish Mucus

Submitted to: American Fishery Society (Fish Health Section) Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2009
Publication Date: June 8, 2009
Citation: Klesius, P.H., Aksoy, M., Shoemaker, C.A., Evans, J.J. 2009. Chemotaxis of Flavobacterium columnare: To Channel Catfish Mucus. In: Proceedings of the American Fishery Society (Fish Health Section).June 8-10, 2009, Park City, Utah. p.26.

Technical Abstract: Flavobacterium columnare is the etiological agent of columnaris disease in fresh water fish. The disease is characterized by chronic skin lesions and severe mortality. The skin mucus constitutes a large portion of body and many infectious organisms including F. columnare, is believed to invade through the skin or colonize the skin. It is hypothesized that F. columnare is attracted to the skin mucus by recognition of and binding to carbohydrate compounds associated with the skin mucus. Isolates of F. columnare belong to either the virulent genomovar II or the less virulent genomovar I. Chemotaxis assays were conducted in vitro using mucus samples from the skin epithelial surface of healthy channel catfish, Ictalurus punctatus. In a previous study, skin mucus was demonstrated to induce a greater chemotactic response in genomovar II than in genomovar I isolates. In the present study, chemotaxis was significantly reduced following treatment of the bacterial cells with sodium periodate. Capsular staining showed a loss of capsule following sodium periodate oxidation. Incubation of mucus with D-mannose resulted in significant reduction of chemotaxis. The results demonstrate that a carbohydrate binding substance (lectin-like) present in the capsule is responsible for the chemotaxis of F. columnare to carhohydrate compounds in the skin epithelial mucus.