Deficit in oxygen causes G(2) budding and unbudded G(2) arrest in Cryptococcus neoformans.

Cryptococcus neoformans exhibited diphasic growth when grown under limited aeration. First, it grew exponentially, but at OD 1, the concentration of dissolved oxygen in culture decreased to 1 mg l(-1) and a second phase of slow growth was started. This phase was characterized by a shift of budding from S to G(2), a sharp decrease in budding index and a sharp increase in the proportion of unbudded G(2) cells to 80%. Thus, a deficit in oxygen was demonstrated to delay the timing of budding, prolong the G(2) phase and cause accumulation of cells after DNA synthesis, but before commitment to budding.