Fig. 5

Posterior lateral line development is disrupted in germ-free embryos. A–C WMISH of isl1 in 4dpf embryos. Larvae from each treatment group were processed in parallel. All groups were stained for the same period of time to allow comparison of GF and ZM groups which have reduced staining, but visible neuromasts (white arrowheads). Experiment was conducted with 8–10 larvae per group. D–F Trunk neuromasts of the posterior lateral line in 3dpf larvae incubated in a mixture of vital dyes Diasp and DiOC6 to identify hair cells (red) and accessory cells (green) of the lateral line. Neuromasts are marked with white arrowheads. The intense staining in the yolk extension provides a useful positioning reference. G–I Posterior trunk neuromasts (solid white arrowheads) and terminal neuromasts (hollow arrowheads) in the tail identified with Diasp and DiOC6 in 3dpf. Tail fins are outlined with dashed line for reference. Terminal neuromasts appear to be smaller and less well-developed in GF larvae. Some neuromasts of the posterior tail, as well as some terminal neuromasts, are missing in GF larvae. More examples are presented in Supplementary Figs. 8, 9 and 10