The effects of compounds on DASPEI and FM1-43FX staining in the pLL. Ototoxin treatment reduced DASPEI and FM1-43FX staining in the hair cells of the pLL compared to control larvae. Other staining, including the nasal epithelium and ear, was not affected in treated larvae (Rows A–F). Treatment with negative control compounds did not reduce the brightness of DASPEI or FM1-43FX labelling in the pLL compared to control larvae (Rows G–I). The images shown are representative of all fish tested (12 larvae per treatment group). Scale bar = 800 μm. (Ji) Schematic showing typical pattern of neuromasts in a 5 dpf zebrafish larva. Smaller neuromasts from the second wave of deposition are indicated (II-1, II-2), but were not scored for the purpose of the DASPEI assay. The remaining 9 neuromasts of the pLL (P1-9) were scored on both sides. (Jii-iii) Exemplar images of neuromast staining with DASPEI. Image (Jii) is representative of a healthy neuromast given a score of 2 in the fluorescence assay. Image (Jiii) is representative of a damaged neuromast, given a score of 1. Scale bar = 20 μm.

The effects of copper sulphate and neomycin exposure on the ear and pLL of Tg(pou4f3::mGFP) larvae. Treatment with neomycin and copper sulphate (E–H) did not affect GFP expression in the hair cells of the inner ear when compared to control treatment (A–D). These images were taken at both the anterior and posterior focal planes in live animals. A, anterior macula; P, posterior macula; arrowheads indicate the cristae of the semicircular canals. Scale bar = 200 μm. Treatment with neomycin (K) but not copper sulphate (L) caused a strong decrease in GFP expression in hair cells of the pLL, when compared to control treatment (I and J). Scale bar = 500 μm. Images are representative of an n of 12 per treatment group.

Development was unaffected by altering the density at which larvae are raised. (A-D) Representative images of larvae reared at a density of 50 per Petri dish (taken from a sample of 150 animals). (E-H) Representative images of larvae reared at a density of 128 per Petri dish (taken from a sample of 128 animals). Note normal development of eye, body pigmentation, body length, and swimbladder inflation for all animals. Scale bar = 500 μm.