g, Quantitative effects of beclin 1 on basal and nutrient-deprivation-induced autophagy of MCF7 cells. Bars indicate mean (±s.e.m.) number of autophagic vacuoles per cell for cells growing in normal media (black), for cells subjected to 4 h of serum and amino-acid deprivation (grey), and for cells pre-treated for 30 min with 10 mM 3-MA and subjected to 4 h of serum and amino-acid deprivation in the presence of 3-MA (open). Mean was determined by counting the total number of autophagic vacuoles in each cell for 100 cells per clone per treatment. 