Figure 1.

VA resistance of the syntaxin mutant md130. (A) Movement of a representative wild-type young adult animal over 30 s in the presence of 2.8% (vol/vol) isoflurane. The animal is on standard nutrient growth medium agar in the absence of a bacterial lawn (23). (B) Movement of a representative md130 young adult animal over 30 s in the presence of 2.8% (vol/vol) isoflurane. (For A and B, bars = 1 mm.) (C) The dispersal index (12) of the fraction of young adult animals moving in 45 min from the center to the edge of a 9.5-cm agar pad rimmed with bacteria is plotted against the percentage of isoflurane concentration (vol%) for both strains. Each data point is mean ± SEM of at least four independent assays performed at the same VA-concentration range. Horizontal error bars represent the SEM of the pooled VA concentrations. Curves were fit to the data by nonlinear regression. The EC₅₀ of isoflurane is 0.74 ± 0.02 for wild type and 4.36 ± 0.36 for md130. (D) Concentration/response curve for halothane. The EC₅₀ is 0.45 ± 0.02 for wild type and 1.29 ± 0.12 for md130.