Linda Rhodes has worked in the areas of aquatic toxicology, molecular immunology, and microbial pathogenesis. She has a Ph.D. in molecular and cellular biology (Department of Biological Structure, University of Washington, 1993), and her dissertation work focused on transcriptional regulation of immunoglobulin expression. As a member of the Environmental Conservation Division, she worked a histopathologist and zoologist in studies examining the relationship between anthropogenic contaminants in marine sediments and diseases of benthic fishes such as English sole (Parophrys vetulus). Her postdoctoral research at the University of Maine at Orono studied the molecular effects and disposition of the contaminant dioxin (TCDD) in soft-shell clam (Mya arenaria) and oncogene alterations in a model fish for fresh-water toxicology, medaka (Oryzias latipes). As a National Research Council associate, she began research in the microbial pathogenesis of Renibacterium salmoninarum, the Gram-positive bacterium that causes bacterial kidney disease in salmonid fishes.
Bacterial kidney disease (BKD) is an endemic, debilitating disease of salmonids, and it is a serious concern in salmon cultivation. Our research uses molecular genetics as a basis for studying this disease and its bacterial agent. Research into the molecular genetics of Renibacterium salmoninarum is directed at identifying and characterizing genes that encode factors important to pathogenesis. We have developed methods for genetic manipulation of R. salmoninarum and shown that the major soluble antigen is a significant virulence factor. Our studies on host response have shown that wild type bacteria appear to suppress genes associated with an effective immune reaction. Clinical research on treatment of BKD has evaluated the impact of repeated antibiotic treatment (including development of an antibiotic resistance assay for this fastidious organism) and the kinetics of macrolides in Chinook salmon. Field studies of free-ranging populations of juvenile Chinook salmon have been conducted to identify important ecological and epidemiological factors that can influence infection, including evidence for potential vectors of transmission.
Environmental microbiology is an emerging area of interest with ties to water quality, food webs, and aquatic animal health. Tools for conducting structural and functional studies in environmental microbiology are being applied in research on water quality in the Whidbey Basin of Puget Sound. These tools have broader applicability for investigations in both marine and freshwater situations.