Electrophoresis of Proteins of 3 Penicillium Species on Acrylamide Gels

SUMMARY Soluble proteins extracted from mycelium of Penicillium griseofulvum were separated by acrylamide-gel electrophoresis. The pattern and overall intensity of the protein bands varied greatly with age of culture. A marked decrease in band intensity occurred at the time of exhaustion of the nitrogen source in shaken cultures, and at an earlier stage in static cultures; the total protein in whole or ultracentrifuged extracts did not decrease to the same extent. Changes in the pattern and intensity of protein bands during incubation occurred also in P. chrysogenum and P. frequentans. Mycelium of P. griseofulvum which was induced to sporulate in shaken culture yielded little protein as shown by electrophoresis at early stages of culture, in comparison with non-sporing mycelium. Each of these three Penicillium species could be distinguished by the protein pattern, which was reproducible and characteristic of the fungus at any particular stage of culture. The results indicate the need to determine the effects of age and conditions of culture when gel electrophoresis of mycelial proteins is used for taxonomic purposes.