Incorporation of [1-C-13] acetate into the heterocyst glycolipids of t
he cyanobacterium Anabaena cylindrica indicated that (i) the long chai
n of the aglycones originates from a de novo biosynthesis and not by e
longation of a preformed shorter molecule and that (ii) there is no ap
parent interconversion between the hydroxyketone and alcohol glucoside
s.