Quantitative analysis of pathogen binding to Atlantic salmon mucins.

Abstract

Mucin containing fractions from individual fish and tissue sites were pooled according to the method shown in Fig 1A (n = 5 for each tissue). Pathogen binding to each of these 25 samples was analyzed using the Bac Titer-Glo method, and the luminescence signals were transformed to CFU/cm2 according to standard curves for each pathogen (Fig 2) to allow comparison of binding levels between pathogens. A. A. hydrophila binding to gill mucins was higher compared to the proximal intestinal mucins: p≤0.05; n = 5). B. V. harveyi bound with no distinguishable organ preference (p = n.s.). C. The level of M. viscosa binding differed between mucin groups (distal intestine vs. skin and gill: p≤0.05). D. Y. ruckeri bound to proximal and distal intestinal mucins more than to gill mucins (p≤0.01 and p≤0.05). Bars denote median ± interquartile range of biological replicates, after subtracting the background signal. The results were reproduced twice. Statistics: Kruskal-Wallis test by ranks with Dunn´s Post Hoc test to compare binding to mucins from different epithelial sites. The numerical p values on the graphs show the result of the test, without the post hoc test. Abbreviations: Pyloric = pyloric cecal mucins; Proximal = proximal intestinal mucins; Distal = distal intestinal mucins.</p