FIG. 7.

Sorbitol dehydrogenase activity in P. infestans. Assays were performed using 1 M sorbitol and tissue extracts from nonsporulating (nonspor.) hyphae, sporulating (spor.) hyphae, purified sporangia, defined media, and defined media with reduced levels of nitrogen (nitrogen starved) and carbon (carbon starved). Activity is expressed as the number of micromoles of sorbitol oxidized per minute per picogram of protein. The data are averages (plus standard deviations) of assays performed on at least two replicate tissue samples made on different days.