INDUCTION OF YEASTLIKE DEVELOPMENT IN <i>MUCOR</i> BY CARBON DIOXIDE

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 N(2), a filamentous (moldlike) growth developed, commonly followed by fragmentation of hyphae into spherical cells (arthrospores). Introduction of CO(2) into an anaerobic atmosphere induced development of spherical, budding yeastlike cells. Anaerobically, a pCO(2) of 0.3 atm or higher produced a purely yeastlike development. Presence of oxygen annulled the effect of CO(2) On germination, spores gave rise directly to either type of vegetative development, depending on the atmosphere of incubation. Induction of yeastlike development by CO(2) occurred in five strains of M. rouxii, and in most species of Mucor tested. M. subtilissimus, however, did not require CO(2); it developed in the yeastlike form under anaerobic conditions. Strains of Rhizopus grew under CO(2), but developed only filamentous mycelium. Members of other genera of Mucorales were unable to grow under an atmosphere of CO(2).