CHARACTERIZATION OF PSEUDOMONAS RHAMNOLIPIDS

The Gram negative organism, Pseudomonas aeruginosa, is often found in the lungs of patients with cystic fibrosis and other forms of severe bronchiectasis, where it secretes a number of extracellular toxins including the mono- and dirhamnolipids. The principal monorhamnolipid from P. aeruginosa has previously been identified as rhamnosyl-3-hydroxydecanoyl-3-hydroxydecanoate (Rh-C10· C10). A number of related mono- and dirhamnolipids have been purified from cultures of a clinical isolate of P. aeruginosa and identified by fast atom bombardment and electron impact mass spectrometry: these contain the 3-hydroxyoctanoyl-3-hydroxydecanoate (C8, ·C10) and 3-hydroxydecanoyl-3-hydroxydodecanoate (C10·C12) homologues. Structural isomers were also present where the order of the lipid linkage was transposed (Rh-C1O·C8 and Rh-C12·C10). Unsaturated mono- and dirhamnolipids containing the 3-hydroxydecanoyl-3-hydroxydodec-5-enoate (C10·C12:1) lipid were also present. © 1990.