A NON-EXTRACTABLE TRITERPENOID OF THE HOPANE SERIES IN ACETOBACTER-XYLINUM

Cells of the bacterium Acetobacter xylinum were analysed for their res idual triterpenoid content after exhaustive lipid extraction using chl oroform/methanol. Whereas the well known bacteriohopanetetrol mixture was present in the extract, the cells still contained a single bacteri ohopanepentol cyclitol ether which could be detected either as the pri mary alcohol derivative after H5IO6 oxidation followed by NaBH4 reduct ion of the already extracted cells or as the octa-acetate by direct ac etylation followed by solvent extraction. This is the first evidence o f a probable selective complexation of a hopanoid via non-covalent lin kages to other cell constituents.