Fig. 4.

Tetrahymena lysate-mediated activation of histidine prototrophism in yeast expressing the Tetrahymena GPCR. Yeast transformants were exposed to the lysates and yeast growth was measured spectrophotometrically at OD₆₀₀. To determine background growth, yeast transformants were grown in media lacking leucine and histidine (untreated control). As an additional control, yeast cells were transformed with a vector encoding an unrelated GPCR (from C. parvum) and then grown in the same conditions. Growth is quantitated as compared to growth observed in untreated controls. Data presented are the mean ± sem for three independent experiments each performed in triplicate. *p<0.05 versus untreated controls.