FIG 1.

Pyomelanin production and hydrogen peroxide-mediated killing of phage-resistant mutants. (A) Treatment of PAO1 with bacteriophages AM.P2, Mat, and Kat led to the generation of pyomelanogenic phage-resistant mutants AM.P2-X-1, Mat-X-1, and Kat-X-2, respectively. (B) Pyomelanin is produced by auto-oxidation and polymerization of excess homogentisate due to the loss of function of hmgA. (C) Visual changes in pigmentation of PAO1, ΔhmgA, and phage-resistant mutants (AM.P2-X-1, Mat-X-1, and Kat-X-2) upon supplementation of 5 mM Tyrosine to growth media and (D) quantified changes in pyomelanin production in the same strains when complemented with functional hmgA. Data are representative of the mean ± SEM of three independent experiments performed in triplicate. *, P < 0.05; ***, P < 0.0005; ****, P < 0.0001, or no statistical significance, ns, denoted based on one-way analyses of variance and Dunnett’s test.