The higher levels of Nos2 mRNA detected during La-arg− infection led to an increased NOS2 expression (Fig. 3A) and NO production after 4 h of infection, which was determined by the increased percentage of cells producing NO (DAF-FM+ cells, Fig. 3B) and by the amount of NO produced per cell (DAF-FM florescence intensity mean, Fig. 3C). Here, NOS2 is linked to infection.