Zbl. Bakt. 285,11-19 (1996) © Gustav Fischer Verlag, Stuttgart· Jena . New York A Chemotaxonomic Study of the Lipoglycans of Rhodococcus rhodnii N445 (NCIMB 11279) CHRISTOPHER FLAHERTY!, DAVID E. MINNIKIN 2 , and lAIN C. SUTCLIFFE*l 1 Departments of Oral Biology and 2 Chemistry, The University of Newcastle upon Tyne, UK. Received February 12, 1996 . Accepted April 1, 1996 Summary Rhodococcus rhodnii N445 was investigated for the presence of macroamphiphilic lipo- glycan. Purification of a hot phenol-water extract by hydrophobic interaction chromatog- raphy allowed the resolution of three lipoglycan fractions. The two main preparations con- tained lipoglycans with carbohydrate compositions consistent with the presence of lipoara- binomannan and lipomannan, whilst the minor fraction appeared to contain a mixture of these two lipoglycans. The fatty acid composition of the lipoglycans resembled that of the whole cells except that the relative proportion of unsaturated fatty acids was decreased. Al- though lipoarabinomannan and structurally-related lipomannan lipoglycans from represen- tatives of the genus Mycobacterium have been extensively studied, this is the first report of the lipoglycan composition of a representative of the genus Rhodococcus as presently de- fined. These findings provide further chemotaxonomic evidence that lipoarabinomannan- type lipoglycans are widely distributed throughout the mycolic acid-containing actinomy- cetes. Introduction The cell envelopes of Gram-positive bacteria contain structurally diverse macroam- phiphiles which can be classed as either lipoteichoic acids or Jipoglycans (6,23). Study of the structural diversity exhibited by both these classes of macroamphiphile, which are distributed in a mutually exclusive manner, is likely to be of chemotaxonomic val- ue (23). Intriguingly, it appears that the synthesis of lipoglycans predominates over that of lipoteichoic acids among actinomycetes, although the majority of taxa remain un- studied. Among the most thoroughly characterised lipoglycans are the lipoarabinomannan (LAM) and structurally-related lipomannan (LM) produced by Mycobacterium spp. * Corresponding author