Halogen- and Sulfur-Containing Lipids of Ochromonas

Although sulfatides have been known since 1874 (41), it was not until 1967 that an aliphatic sulfate, of the detergent variety, was positively identified in the biosphere, namely in the phytoflagellate, Ochromonas danica (27). As synthetic detergents, alkyl sulfates had been used commercially for more than 25 years. Many other sulfolipids had been characterized (18), but each of these was also a glycolipid, i.e. either a sugar sulfate or a sugar sulfonic acid. Alkyl sulfates comprise the only group of lipid molecules which contain polar groups at both ends of the molecule. This fact is especially significant in the context of our understanding of membrane structure. These compounds are I, 14-docosane­ diol-l,14-disulfate, and a group of polychloro derivatives with from 1 to 6 chiaro groups replacing hydrogen atoms on the chain (9, 21). The compounds are also unique as the only halolipids to be characterized in natural fats. In addition to the novel chemical structures of these substances, their physiology is somewhat unusual. For example, these sulfatides are not metabolized by the microbe since the sulfate ester is not cleaved (20). Furthermore, the concentration