Fig. 7. Phluorin-expressing wild-type cells were grown to early logarithmic phase in EMM pH 5.5 and mounted in the same media in the flow chamber. After a 30-60 minute equilibration time the medium was switched (t=0) to EMM(minus nitrogen) pH 5.5. The top panel shows the mean internal pH of 20-40 cells plotted as a function of time. Error bars indicate s.d. Lower panels are scatter plots of internal pH as a function of cell length at the times indicated. Open diamonds indicate binucleate cells, whereas closed diamonds indicate uni-nucleates.