Research Snapshot

• Establishing screening platforms: Swimming activity of larval and adult zebrafish
• Development and activity of microglia in the zebrafish brain

Establishing screening platforms: Swimming activity of larval and adult zebrafish

Swimming activity of larvae and adult fish is monitored in response to light and dark switches using ViewPoint – Zebrabox video tracking system and software.

Larvae in a 24-well plate

Light on - 6min; light off - 4min; light on - 4min; 14min recording

Larvae in a 96-well plate

3s flash of light at 1min, 2min, and 3min recording

Adult fish 1

Light on - 10min; light off - 5min; 15min recording

Adult fish 2

Light on - 10min; light off - 5min; 15min recording

Development and activity of microglia in the zebrafish brain

Confocal microscopy of transgenic zebrafish larvae expressing mCherry and GFP in macrophage-derived microglia

Dorsal view of the distribution of mpeg1:mCherry microglia in the optic tectum at 3 dpf. The fluorescent signal shows the cytoplasm of the microglia and the transmission image shows the parenchyma and blood vasculature of the optic tectum. Depth = 115.86 µm. Scale bar = 50 µm. Anterior is to the left in this and all following movies.

Example of a ramified mpeg1:mCherry expressing microglial cell in the optic tectum at 11 dpf. Dynamic activity occurs at the endings of the thin processes while the cell body remains sessile. Depth = 25 µm. Scale bar = 10 µm. Time = 45 mins 26 secs. Each frame = 2 mins 16 secs.

EGFP microglia undergoes mitotic division in the optic tectum at 4 dpf. Division occurs after all processes have been withdrawn. Note how the daughter cells rapidly sprout processes. Depth = 31.5 µm. Scale bar = 10 µm. Time = 1 hr 59.6 mins. Each frame = 5 mins 12 secs.