STEROLS OF THE BROWN TIDE ALGA AUREOCOCCUS ANOPHAGEFFERENS

Aureococcus anophagefferens, an alga responsible for ''brown tide'',:c ontains 24-methylenecholesterol as 48% of the free sterols and (E)- an d (Z)-24-propylidenecholesterol as 32% and 12% respectively. This is t he first isolation of appreciable amounts of (Z)-24-propylidenecholest erol from an alga and suggests that Aureococcus anophagefferens may be the source of the (Z)-24-propylidenecholesterol isolated from various marine invertebrates. 24-Propylidenecholesterol is proposed to be a c hemotaxonomic marker for the Pelagophyceae, a new class of chrysophyte s which includes the Sarcinochrysidales. (C) 1998 Elsevier Science Ltd . All rights reserved.