FIG. 10.

Deletion of the K. lactis gene KlPNT1 causes a nonrespiratory phenotype and the absence of cytochrome c oxidase activity. (A) The Klpnt1 deletion strain (SH702) was transformed with either a KlPNT1 plasmid (pSH505) or the empty vector (pROCS2). The transformants were streaked on glucose minimal medium (SD-ura) selecting for the plasmids or on YPEG and incubated at 30°C for 2 days before being photographed. (B) Crude mitochondria were isolated from KB101 (KlPNT1) and SH702 (Klpnt1Δ::hisG) as described in Materials and Methods, and cytochrome oxidase was assayed by the same procedure as in the experiment Fig. 7. The error bars show the standard deviation of four independent measurements.