Figure 2

CBN exposure alters the development of hair cells associated with the otoliths and the lateral line. (A) Bar graph represents the (%) of embryos that responded to sound/vibration stimuli at 5 dpf. The sound/vibration pulse was delivered to free-swimming embryos from a speaker that was in contact with the base platform and their escape responses were recorded. N = 3 experiments. (B) Images of otoloths were taken from 52 hpf old embryos, positioning anterior (head) on right and posterior (tail) on left. The otic vesicles (OV), utricular otolith (UO) and saccular otolith (SO) and semicircular canal (SC) are visible here. N = 3 experiments. Scale bar represents 50 µm. (C) Scanning electron microscopy (SEM) images of embryos at 5 dpf. Top rows, images were taken of the otolith at ×500 magnification. Bottom rows, images were taken from inside the otolith at ×10,000 magnification. Kinocilia can be seen emanating from hair cells. Scale bar represents 100 µm (top panel) and 5 µm (bottom panel). N = 3 experiments. (D) Bar graph of vehicle controls (n = 6), 0.01 mg L⁻¹ (n = 8) and 4 mg L⁻¹ (n = 8) groups showing the % of embryos that exhibited changes to the tight bundled structure of kinocilia. N = 3 experiments. (E) SEM images of embryos along the posterior lateral line (pLL) at 5 dpf. Top row shows images of vehicle control, 0.01 mg L⁻¹ CBN and 4 mg L⁻¹ CBN treated groups. Images were taken of the lateral line at ×500 magnification. Bottom row shows the SEM image of the first neuromast along the lateral line. These images were taken at ×10,000 magnification. Scale bar represents 100 µm (top panel) and 5 µm (bottom panel). N = 3 experiments. (F) Bar graph showing the number of neuromasts along the posterior lateral line in vehicle controls (n = 6), 0.01 mg L⁻¹ (n = 6) and 4 mg L⁻¹ (n = 6) groups. N = 3 experiments. Groups which share the same letter(s) of the alphabet are not statistically different from one another; p < 0.05.