INDUCTION OF YEASTLIKE DEVELOPMENT IN MUCOR BY CARBON DIOXIDE

ABSTRACT

Bartnicki-Garcia, S. (Rutgers, The State University, New Brunswick, N. J.) and Walter J. Nickerson. Induction of yeastlike development in Mucor by carbon dioxide. J. Bacteriol. 84:829–840. 1962—Vegetative development of Mucor rouxii may follow either one of two patterns of morphogenesis (mold-yeast dimorphism), depending on the atmosphere of incubation. Under air or N₂, a filamentous (moldlike) growth developed, commonly followed by fragmentation of hyphae into spherical cells (arthrospores). Introduction of CO₂ into an anaerobic atmosphere induced development of spherical, budding yeastlike cells. Anaerobically, a pCO₂ of 0.3 atm or higher produced a purely yeastlike development. Presence of oxygen annulled the effect of CO₂ On germination, spores gave rise directly to either type of vegetative development, depending on the atmosphere of incubation. Induction of yeastlike development by CO₂ occurred in five strains of M. rouxii, and in most species of Mucor tested. M. subtilissimus, however, did not require CO₂; it developed in the yeastlike form under anaerobic conditions. Strains of Rhizopus grew under CO₂, but developed only filamentous mycelium. Members of other genera of Mucorales were unable to grow under an atmosphere of CO₂.