FIG 6.

The F. psychrophilum phage-resistant isolates displayed reduced biofilm formation and secretion of extracellular enzymes. (a) Biofilm formation of the 950106-1/1 ancestral strain and the six phage-resistant isolates; (b) hemolytic activity; (c) total protease activity on skim-milk plates; (d) gelatinase activity on gelatin plates. Results were plotted with standard deviation error bars from triplicate experiments for each isolate; the P value was calculated using a paired Student t test. Asterisks indicate values significantly lower than that of the control.