Adaptation to cycloheximide: in vitro studies with filamentous fungi.

Adaptation of numerous strains of filamentous fungi to cycloheximide was noted upon first transfer during serial exposure to the antibiotic. The extent of this adaptation varied in part with the species and strain of the microorganism. Exposure on subsequent transfers caused no change in the growth of any of the strains used. These results suggest that nonzoopathogens may be differentiated from zoopathogens on the basis of adaptation to cycloheximide and that such adaptation might also be found in other eucaryotes.