ROS produced after physical injury and after cell death.

<p>(A) Cut disc cultured ex vivo (white wedge indicates cut edges) and thermal LUT of CellROX Green. (B) Cut disc cultured ex vivo, imaged at just after cut (0–5’) and 30’ later. Thermal scale indicates pixel intensity. (C) Sketch of wing imaginal discs with the area (black square) shown in A, B and E. (D) Fixed disc stained for nuclei to show disc contour (TP-3: TO-PRO-3) and caspase-3 after <i>ptc>rpr</i> activation for 11h at 29°C. (E) <i>ptc>rpr</i> disc cultured ex vivo; basal images at the bottom, apical at the top. Left, cell death (TO-PRO-3). Right, thermal LUT taken from the ROS channel (CellROX Green) of the same preparation. Note that most dead cells (TO-PRO-3 positive) show high ROS (red in thermal image) whereas living cells (TO-PRO-3 negative) had low ROS (green-cyan in thermal image). (F) Mean pixel intensity (grey value) of the indicated zones in control discs without cell death (<i>ptc>rpr</i> OFF) and discs with cell death (<i>ptc>rpr</i> ON). The pixel intensity in the <i>ptc</i> domain in the absence of cell death (<i>ptc>rpr</i> OFF) was 1.76 ± 0.55 (SD; from 48 regions of interest [ROI] in n = 5 discs). The mean pixel intensity for the apoptotic region (basal; <i>ptc>rpr</i> ON) was 33.14±8.18 (SD), measured in 27 ROI on confocal images taken from n = 6 discs. Living cells adjacent to the apoptotic zone showed a mean grey value of 8.51±2.12 (SD; 15 ROI from 6 discs taken from cells near the <i>ptc</i> domain). White rectangles in E: example ROI for Basal Apoptotic Zone (1) and Apical Living Zone (2). The ROI’s for the <i>ptc</i> Zone, in discs in which <i>ptc>rpr</i> is OFF, were placed as (1). ***<i>P</i><0.001. Thermal scale indicates sample values from raw images.