“…1 ) A typical blood-red pigment, prodigiosin, from Serratia marcescens has been known since 1902, but it is a nondiffusible, water-insoluble pigment bound to the cell envelope. Its chemical structure, with tri-pyrrole rings, was established together with those of related compounds,2) and biological activities such as antimicrobial or immunorepressive ones have been found.…”