Figure 2. Ethanol conditioning induces a withdrawal phenomenon in the food race.

A Diagram showing the conditioning paradigm. Developmentally staged worms were placed on agar plates with an excess of E. coli OP50 and agar containing ethanol. At the end of the conditioning period, the worms were washed from the plates in M9 buffer, washed once more in M9 to remove residual ethanol and E. coli, and then aliquoted onto the food race plate. Three sets of experiments were performed in which either the conditioning time was varied (B), or the conditioning time was set and the recovery time was varied (C), or the conditioning time and recovery time were set and the conditioning concentration of ethanol was varied (D). Parallel controls were performed in which ethanol naive worms raised for similar time-periods were tested for performance in the food race. These indicated no significant effect of the culture time on performance (95±5%, n = 3, reached the food source by the 2 h time-point for L4 plus 1 day worms, and 93±4% for L4 plus 2 days.) B The effect of varying the time-course of ethanol conditioning on performance in the food race. Worms were conditioned on ethanol for the time indicated. 0 h (n = 5); 2 h (n = 6; p>0.05 compared to 0 h); 4 h (n = 4; p>0.05 compared to 0 h); 6 h (n = 7; p<0.001 compared to 0 h); 24 h (n = 6; p<0.001 compared to 0 h); 48 h (n = 4; p<0.001 compared to 0 h). C The effect of varying the recovery time from conditioning on performance in the food race. The recovery times are as indicated. 0 h (n = 6); 2 h (n = 4; p>0.05 compared to 0 h); 4 h (n = 4; p>0.05 compared to 0 h); 8 h (n = 4; p<0.001 compared to 0 h); 16 h (n = 4; p<0.001 compared to 0 h). The experiment was also performed on worms conditioned on ethanol for 48 h which exhibited similar recovery times (see text for details). D The effect of varying the conditioning ethanol concentration on performance in the food race. Worms were conditioned on ethanol for 48 h at the concentration indicated. Each point is the mean of a duplicate determination. Statistical analysis was performed using one way ANOVA with Bonferroni multiple comparisons post-test on the last time-points.