The gliding bacterium Herpetosiphon giganteus Hp a2 was shown to contain γ-carotene, one monoglucosyloxy and two new diglucosyloxy carotenoids with a x-O-acyl-diglucosyloxy carotenoid as main component. Flexirubin-like pigments could not be detected in this organism.
As in the Myxobacterales and Cytophagales (Kleinig et al., 1974) menaquinones (MK-6 and MK-7) were found to be the only isoprenoid quinones present in Herpetosiphon.
The chemosystematic implications of these findings are briefly discussed.