Figure 1.

psNTP9 complements a Pi-uptake mutant. A, pYES2 vector alone and pYES2/psNTP9 were transformed into NS219. Single colonies were picked and grown in low-Pi medium. Values represent the averages of two independent transformants. Inset shows a western blot of the psNTP9 transformant and a control (vector alone). B, Growth of the mutant transformed with the pea apyrase and a mock transformant at five Pi concentrations. Values are the averages of two independent transformants for two separate experiments. Cultures were inoculated with 10⁴ yeast cells from a log-phase culture. C, Acid-phosphatase activity in NS219 yeast: two independent NS219 transformants harboring the vector alone show the dark staining of the mutant, whereas two independent NS219 transformants carrying the pea apyrase gene psNTP9 show the light staining of the wild type.