Lipid level and total fatty acid composition for selected developmental stages of Entomophthora egressa

Abstract

The major fatty acids (> 10%) of Entomophthora egressa were C16:0 and C18:1. Minor fatty acids, which varied with the stage of fungal development, included C11:0, C12:0, C13:0, C14:0, C15:0, C16:1, C17:0, C18:0, C18:2, C18:3, C20:1, C20:2, C20:3, C20:4, C20:5, and two unidentified unsaturated fatty acids. Differences were observed between the total fatty acid levels of C12:0, C14:0, C17:0, C18:0, and C20:5 and the degree of unsaturation of the fatty acids of 37-h protoplasts grown in modified Grace's medium and a simplified growth medium (SGM). The levels of C12:0, C14:0, C18:1, C20:4, and C20:5 decreased and the levels of C18:0 and C20:2 increased with the formation of spherical hyphal body (shb) initials. With the production of mature shb increased levels of C12:0, C14:0, C15:0, C18:1, C20:4, and C20:5 were detected. During the germination of the shb the levels of C14:0, C16:1, C18:1, and C20:4 increased, whereas C15:0 and C20:5 levels declined. The fatty acid levels, except for Cl2:0, C13:0, and C20:2, remained constant during the mycelial stage. The degree of fatty acid unsaturation decreased during early stages of development (protoplasts through shb initials). In SGM the degree of fatty acid unsaturation was lowest during the shb initial stage and highest during the shb stage. The total lipid level increased during shb maturation and declined during shb germination.