For this trial I prepared 2mL of 3IY (10mg/ml in 5% Sucrose) 30 minutes before applying it to 8 pieces of filter paper stacked in the glass vial. I pipetted the whole volume of 2mL into the vial and discarded the excess liquid.

Recent results revealed problems with our negative control (Gr28bd-Gal4; TrpA1-Gal4+ EtOH) treated with EtOH. As the food for these flies was not substituted with ATR but only with Ethanol (ATR is dissolved in EtOH), the Chrimson channel should be non-functional in this group and the flies should therefore not avoid light. However, we observed negative PIs for this group. Since some activation of the Chrimson channel could be possible even without ATR, I tried to lower the used light intensity to values where the positve control would still avoid light, but the intensity would be too low for the Chrimson channel to activate when no ATR is present.

It seems that 650 Lux might still be too high. Therefore I will conduct another trial with 500 Lux.

Redlight

N=20

Experiment group = A

bluelight

N=20

Experiment group = A

Gustatory preference under redlight

Gustatory preference under bluelight

It’s not yet confirmed, that the 3IY treatment is working

To see whether the initial preference but also the preference shift, observed for flies expressing the optogenetic Chrimson-Channel in neurons from the PPM2 cluster (tested for preference in JoyStick and T-Maze), does depend on dopamine signaling, I want to repeat these experiments with dopamine depleted flies. For this I plan to use 3-Iodo-Tyrosine, which should reduce dopamine production. To verify the effect 3IY I conducted two sets of experiments, testing locomotion and geotaxis. Successfully depleting dopamine should decrease locomotion and performance in geotaxis assays. At this point both experiments have the same outcome, that the tested method to apply 3IY does not work.

Locomotion in open field arena

Geotaxis in Benzer Counter-Current

Gustatory preference under redlight