CHARACTERIZATION OF NOVEL LONG-CHAIN 1,2-DIOLS IN THERMUS SPECIES ANDDEMONSTRATION THAT THERMUS STRAINS CONTAIN BOTH GLYCEROL-LINKED AND DIOL-LINKED GLYCOLIPIDS

In this study, we purified and characterized tetra-and triglcosyl glyc olipids (CE-S and GL-2, respectively) from two different colonial form s of Thermus scotoductus X-1, from filiformis Tok4 A2, and from T. osh imai SPS-11. Acid hydrolysis of the purified glycolipids liberated, in addition to the expected long-chain fatty acids, two components which were identified by gas chromatography-mass spectrometry as 16-methylh eptadecane-1,2-diol and 15-methylheptadecane-1,2-diol. Fast atom bomba rdment mass spectrometry of the intact glycolipids indicated that a ma jor proportion consisted of components with glycan head groups linked to long-chain 1,2-diols rather than to glycerol, although in all cases glycerol-linked compounds containing similar glycan, head groups were also present, As in other Thermus strains, the polar head group of GL -1 from T. filiformis Tok4 A2 and from T.scotoductus X-l colony type t 2 was a glucosylgalactosyl-(N-acyl)glucosaminylglucosyl moiety, Howeve r, GL-2 from T. scotoductus X-1 colony type fl and from T. oshimai SPS -11 was a truncated analog which lacked the nonreducing terminal gluco se. Long-chairs 1,2-diols have been previously reported in the polar l ipids of Thermomicrobium roseum and (possibly) Chloroflexus aurantiacu s, but to our knowledge, this is the first report Of their detection i n other bacteria and the first account of the structural determination of long-chain diol-linked glycolipids.