Phototoxicity and cytotoxicity assays with para-aminoblebbistatin or blebbistatin and fluorescent imaging in the presence of the myosin II specific inhibitors.(a) Maximum intensity projections of fluorescent confocal microscopic z-stack images of EGFP-α-tubulin H2B-mCherry HeLa Kyoto cells at the beginning and at the end of a 12-hour time-lapse imaging in the presence of 50 µM AmBleb or Bleb. Blebbistatin treated cells display severe phototoxicity (white arrowhead). (b) Lifespan cytotoxicity assays of zebrafish embryos (n = 20) incubated at increasing concentrations of AmBleb and Bleb (inset) in dark. (c) Fluorescent confocal microscopic images of HeLa Kyoto cells in the presence of 50 µM inhibitor concentrations on the 3^rd day of the experiment presented in Fig. 3e,f. (d) 48 hpf (hours-post-fertilization) cldnb:EGFP zebrafish embryos in the absence (Control) and in the presence of 20 µM of the myosin II inhibitors after 24 hours of incubation. Red arrowheads mark the position of the pLLps.