PIGMENT OF PSEUDOMONAS-PAUCIMOBILIS IS A CAROTENOID (NOSTOXANTHIN), RATHER THAN A BROMINATED ARYL-POLYENE (XANTHOMONADIN)

The main pigment from Pseudomanas 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 genus Xanthomonas, has been shown to be the carotenoid (2 R, 3 R, 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 phytopathogenic Xanthomonas 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 by P. paucimobilis might serve as a chemotaxonomic marker for this nonphotosynthetic bacterial species. Certainly, it supports the placement of P. paucimobilis outside the genus Xanthomonas. © 1979 Springer-Verlag New York Inc.