chs5 spa2 mutant has a severe growth defect at 37°C that can be rescued by sorbitol. (A) Isogenic wild-type (Y603), spa2 (Y601), chs5 (Y1935), and chs5 spa2 (Y1936) strains were grown overnight to stationary phase at 30°C in YPDAS. Ten-fold serial dilutions starting with the saturated culture (∼5 × 107 cells/ml) were spotted in 5-μl drops onto YPDA plates (two upper panels) or YPDAS (lower panel). Plates were incubated at 30°C (upper panel) or 37°C (two lower panels). (B) Morphology of chs5 spa2 cells (Y1936) incubated at the restrictive temperature in YPDA for 6 h; elongated necks, large round cells, and shmoo-like cells are shown from left to right.