β-L-Gulopyranosyl-caldarchaetidyl-glycerol is the main polar lipid of the archaeon T. acidophilum. Cellular levels of β-L-gulopyranosyl-caldarchaetidyl-glycerol in T. acidophilum HO-62 positively and negatively correlate with increases in culture pH and temperature, respectively. β-L-gulopyranosyl-caldarchaetidyl-glycerol has been used as a standard for the quantification of polar lipids extracted from T. acidophilum HO-62. [Matreya, LLC. Catalog No. 1303]