Crystalloid bodies in Euglena.

A study has been made of the formation of crystalloid bodies (CB) in the cytoplasm of Euglena gracilis. CB have been found in strains of three bleached mutants as well as in the green wild type where they have been hitherto unknown. These bodies accumulate in the lag-phase of growth in media rich in organic carbon source (ethanol, acetate or sugars). The formation of CB is light-independent and reversible. The ultrastructure of CB reveals that they consist of aggregates of thin plates which are often associated with an osmiophilic substance. Several properties of CB indicate that they do not represent paramylon but are mostly lipid in nature and consist primarily of crystalline wax esters. The formation and role of CB is discussed.