Uptake of metabolites by germinating blastospores of Histoplasma capsulatum

The uptake of radioactive L-leucine, L-glutamic acid, and guanine was monitored during blastospore germination of Histoplasma capsulatum. Blastospores of H. capsulatum, grown in Salvin's medium at 37 degrees C for 48 h and shifted to 23 degrees C, germinated within 24 h. Metabolite uptake was faster in mycelial cells at 23 degrees C than it was in yeast cells at 37 degrees C. During the yeast to mold transition, the initial rate of uptake was first markedly depressed and then increased and achieved a level characteristic of the mycelial phase of growth. Estimates of macromolecular synthesis occurring during transitional morphological events might be influenced by these differences in the rate of uptake.