Fig. 2. Expression of nitric oxide synthase (NOS) in insect tubules. Tubules were dissected from the following species: Drosophila melanogaster (A); Aedes aegypti (B); Anopheles stephensi (C); Glossina morsitans (D) and Schistocerca gregaria (E). NOS distribution in intact tubules is shown using anti-uNOS antibody (Broderick et al., 2003; Dow and Davies, 2001; Gibbs and Truman, 1998); cell nuclei were visualised with DAPI (Broderick et al., 2004). Single tubules are shown in each panel, viewed by epifluorescence. Samples were viewed at 10x magnification unless stated otherwise. Tubule diameters can be taken as 35 µm. (Ai) control Drosophila tubule (no antibody); (Aii) pair of tubules showing NOS staining in tubule main segment (m); no staining in initial (i) and lower (l) regions; (Aiii) DAPI staining reveals cell nuclei; (Bi) control A. aegypti tubules (no antibody); (Bii) NOS staining throughout A. aegypti tubule principal cells (excluded stellate cells indicated by yellow arrow); DAPI staining reveals cell nuclei; (Biii) high magnification (50x) showing NOS staining in principal cells; unstained stellate cells indicated by yellow arrows; (Biv) NOS and DAPI-stained tubule, viewed at high magnification (50x); existence of unstained stellate cells confirmed by presence of smaller nuclei compared with principal cells, indicated by arrows; (Ci) control A. stephensi tubules (no antibody); (Cii) NOS staining throughout A. stephensi tubule principal cells (excluded stellate cells indicated by yellow arrow); DAPI staining reveals cell nuclei; (Ciii) high magnification (50x) showing NOS staining in principal cells; unstained stellate cells indicated by yellow arrows; (Civ) NOS and DAPI-stained tubule, viewed at high magnification (50x); existence of unstained stellate cells confirmed by presence of smaller nuclei compared with principal cells, indicated by arrows; (Di) control G. morsitans tubules (no antibody); (Dii) anti-NOS antibody-stained intact G. morsitans tubule at low magnification; DAPI staining reveals cell nuclei; (Diii) anti-NOS antibody-stained tubule at high magnification (20x); (Div) same preparation as Dii, viewed at high magnification (20x); (Ei) control S. gregaria tubules (no antibody) viewed at 20x magnification; (Eii) anti-NOS antibody-stained intact tubule viewed at 20x magnification; close-up view indicates clear staining at the membrane and cytosol; (Eiii) anti-NOS antibody-stained intact tubule viewed at 20x magnification; DAPI staining reveals cell nuclei.