Based on the tissue expression analysis of CanA, NOS1 and NOS2, and the responses of these three genes to bacterial infections in O. furnacalis, we inferred NO production induced by bacteria in hemocytes increased the expression of CanA in hemocytes together with some unknown factors, which were released from hemocytes to induce AMPs expression in fat body via IMD pathway (Figure 9). This evidence concerns the gene NOS2 and bacterial infectious disease.