Total and free ergosterol in mycelia of saltmarsh ascomycetes with access to whole leaves or aqueous extracts of leaves.

Three species of saltmarsh ascomycetes were grown in the presence of all of the constituents of their natural substrate (leaves of cordgrass) or were presented only with aqueous extracts of the leaves. These two growth-condition treatments had no significant effect on total ergosterol content of the fungal mycelia, contrary to an earlier hypothesis that availability of plant lipids would lower fungal ergosterol contents. Mycelial content of free ergosterol was about twice as variable as that for total (free plus esterified) ergosterol. Total ergosterol (data pooled for all species) was strongly correlated to organic mycelial mass (r = 0.43, P < 0.00001, and slope = 4.59 mug of ergosterol mg of organic mass).