Figure 6

(A) Changes in the acidification kinetics of the alveolar sacs and cytoplasmic vacuoles after the addition of Tris-PPi (1 mM) and MgSO₄ (1.3 mM), and after 30 and 60 min (detected by fluorescence microscopy). An increase in acidification was detected by the change in fluorescence emission in the acridine orange stain from green (not acidified) to red (acidified). (B) Quantification of the expression of the H⁺-PPases (PdVP1 and PdVP2) obtained under the same conditions as (A). The bars express the mean values ± the standard error (SE) (n = 5) in the fold change in gene expression. The same and different letters indicate respectively the absence or presence of statistically significant differences (P < 0.05) relative to the control (time 0). Scale bar = 10 μm.