The pigment ofPseudomonas paucimobilis is a carotenoid (Nostoxanthin), rather than a brominated aryl-polyene (xanthomonadin)

The main pigment from Pseudomanas paucimobilis, a bacterium isolated from the hospital environment or clinical pecimens and sometimes confused with members of the genusXanthomonas, has been shown to be the carotenoid (β,β-carotene-2,3,2′,3′-tetrol (nostoxanthin) rather than a brominated aryl-polyene (xanthomonadin) pigment.

Abstract

The main pigment fromPseudomanas paucimobilis (formerly, Weaver's group IIk, biotype 1), a bacterium isolated from the hospital environment or clinical pecimens and sometimes confused with members of the genusXanthomonas, has been shown to be the carotenoid (2R, 3R, 2′R, 3′R)-β,β-carotene-2,3,2′,3′-tetrol (nostoxanthin) rather than a brominated aryl-polyene (xanthomonadin) pigment of the sort characteristically and invariably made by phytopathogenicXanthomonas species. This identification was based primarily on mass spectrometric, nuclear magnetic resonance, and circular dichroism data. Nostoxanthin has hitherto been reported to occur only in a few species of cyanobacteria. Hence, the formation of nostoxanthin byP. paucimobilis might serve as a chemotaxonomic marker for this nonphotosynthetic bacterial species. Certainly, it supports the placement ofP. paucimobilis outside the genusXanthomonas.