Lipid composition of the mycelium of the fungus Mucor hiemalis cultivated with trehalose, triacylglycerols, and itraconazole

Abstract

We investigated the growth and cell lipid composition of the fungus Mucor hiemalis VKMF-1431 cultivated under aerobic conditions in the presence of the morphogenetic agents itraconazole, exogenous triacylglycerols, and trehalose. The sporangiospores of a 6-day culture were used as inocula. Under these conditions, the fungus produced mycelium; nevertheless, solitary yeastlike cells also developed on the glucose-containing medium and in the presence of itraconazole and sterilized triacylglycerols (sTAGs). No yeastlike growth occurred in the system with trehalose and with unsterilized (native) TAGs (nTAGs). With trehalose and nTAGs in the cultivation medium, the ratio between PEA and PC, the two main types of membrane lipids, was low. This testified to a relatively high PC percentage and, accordingly, a stable structure and a highly functional state of the membranes. Moreover, if the development of the fungus occurred exclusively as mycelium formation, the level of polyunsaturated fatty acids (γ-linolenic and arachidonic acid) increased in the presence of trehalose and that of linoleic acid increased in the presence of nTAGs. These results may suggest that unsaturated fatty acids and membrane lipids are related to the cell wall formation and the implementation of morphogenetic programs in mucorous fungi.