Characterization of glycolipids from Meiothermus spp.

Thin-layer chromatographic analysis of the polar lipids of Meiothermus stra ins revealed two glycolipid bands with similar chromatographic mobility to the major glycolipid of Thermus strains. In this study the glycolipids from the type strains of Meiothermus ruber, Meiothermus chliarophilus, Meiother mus silvanus and Meiothermus cerbereus were characterized using CC, GUMS, f ast atom bombardment MS and chemical methods. All strains contained dihexos yl(N-acyl)hexosaminylglucosyl diacylglycerols, related in structure to the major glycolipid of Thermus strains but varying in their fatty acylation pa ttern. The detection of two glycolipid bands by TLC in Meiothermus spp. was attributable to the invariable presence of 2-hydroxyacyl groups N-linked t o the hexosamine of the polar head group which cause the glycolipids to be more strongly retained on silica TLC plates than 3-hydroxy or non-hydroxyla ted N-acyl glycolipids of similar structure that are also present. M. silva nus contained, in addition to these glyceroglycolipids, several glycolipids which were linked to acylated branched octadecanediols rather than to glyc erol. The presence of glycolipids containing 2-hydroxyacyl groups N-linked to hexosamine appears to be a stable phenotypic marker that distinguishes t he genus Meiothermus from the genus Thermus.