Pyocyanin

Part of speech: noun

Definitions

1. A blue-green pigment secreted by the bacterium Pseudomonas aeruginosa, which plays a role in bacterial virulence and biofilm formation
2. A blue-green compound produced by certain bacteria as a secondary metabolite, conferring a distinctive coloration to bacterial cultures and contributing to pathogenicity
3. A pigmented molecule generated by Pseudomonas aeruginosa that gives colonies their characteristic blue-green appearance and functions in bacterial virulence mechanisms

Etymology: In Greek, "pyon" meant pus and "kyanos" meant dark blue, so the name of this pigment joins the two. It was named for the blue-green tint it gives to pus from infected wounds, where the bacterium produces it. The Greek "kyanos" is also the source of "cyan" and "cyanide." The ending "-in" is the standard chemical suffix for a compound, so the name is a plain, descriptive coinage rather than an old word repurposed. The organism's name, "aeruginosa," is Latin for "rust-coloured" or "verdigris-like," and it refers to the green-blue colour of cultures.