Figure 5

Autofluorescence generated by benzaldehyde in the veins of a Drosophila wing.

(A) The four photographs represent exposure to benzaldehyde (10 μl on a paper towel soaked in water and placed in a 200 ml Drosophila vial) of living seven day old Drosophila females. 1–4 represent the time of exposure at 0, 1, 2 and 4 hours, respectively. At the right of each photograph is shown the relative intensity of the autofluorescence corresponding to the two white cross traits from a range of 0 to 1. The asterisks correspond to the average of five experiments and represent the mean + /−SE. 0 h: 0.15 + /−0.05 for both stars; 1 h: 0.3 + /− 0.1 for both stars; photo 2 h: 0.45 + /−015 and 0.55 + /−0.25, respectively; 4 h: 0.75 + /− 0.2 and 0.85 + /−0.5, respectively. A Student’s t-test analysis gives a p < 0.001 between the corresponding determinations at 2 and 4 hours (photos 3 and 4). (B) The same experiment was conducted in identical conditions, but cut wings were used instead of living animals. The relative fluorescence intensity corresponding to white traits in the photographs are represented in the graphs at the right (average of n = 5 experiments). In cut wings, no significant differences were observed between 1 and 2 that correspond to the time of exposure at 0 and 4 hours, respectively. We observed that the benzaldehyde covalent binding marks the tracheal network in wings and this labelling requires living animals with an intact respiratory system.