FIG. 3.

Comparison of the pH of compartments containing Ad5 or Ad7. A549 cells were infected with carboxyfluorescein-Ad (10¹¹ particles/ml) for 10 min at 37°C and incubated at 37°C for various times. pH measurements were performed in living cells by recording carboxyfluorescein emission intensity following excitation at either 490 or 450 nm. (A). Standard curve of carboxyfluorescein-Ad5 using cells equilibrated with 50 mM methylamine buffers (pH 5.0 to 7.5). The fluorescence intensity ratio (I₄₉₀/I₄₅₀) is related to the pH of the standard medium. Bars show the 95% confidence interval. (B) Carboxyfluorescein-Ad5, 10-min pulse (infection) and 10-min chase (incubation). (C) Carboxyfluorescein-Ad5, 10-min pulse and 60-min chase. (D) Standard curve of carboxyfluorescein-Ad7. (E to J) Carboxyfluorescein-Ad7, 10-min pulse with various chase times as indicated (10 to 480 min).