FIG 4.
Characterization of melanin produced from V. natriegens. (A) FTIR spectra of bacterial (Bac) melanin and synthetic (Syn) melanin. Peaks in common and their assignments are 1,625 cm−1, C=C vibration in aromatic (indole) ring; 1,722 cm−1, C=O carbonyl group vibration from carboxylic acid in DHICA; triple peaks at ∼2,900 cm−1, CH2 alkyl vibration; and broad peak centered at 3,415 cm−1, O-H hydroxyl vibration. a.u., arbitrary units. (B) EPR spectra of melanin (Mel) powders, dried melanized and nonmelanized V. natriegens (Vnat) cells, and melanin ghosts. (C) EPR changes of melanin ghosts and dried melanized cells responding to illumination. arb., arbitrary.