Measurements in ImageJ/Fiji A–D measurements of SJ characteristics A the length of a continuous array of septa was measured using the “segmented line” tool B the spacing between consecutive septa in an array is indicated C the thickness of septa is labelled D the width of intercellular space in the SJ region E–G measurements of AJs E the width of intercellular space in the AJ region F measurement of the distance of AJ from the apical membrane (red arrow) G measurement of the AJ length. Abbreviations: AJ: adherens junction; AM: apical membrane; SJ: septate junction. Scale bars: 200 nm (A); 100 nm (B–G).