For Legionella producing RpRalF1–342SS the highest percentage of vacuoles having detectable levels of Arf1-GFP were observed at 30 min post-infection, and Arf1-GFP levels then began to drop to the point where almost no Arf1-GFP staining was observed on vacuoles after 4 hours of infection. The gene discussed is ARF1; the disease is infection.