Fig. 4. Vesicle-enriched fractions from white, brown and scarlet mutants have reduced biogenic amines. (A) The pellet and supernatant fractions after centrifuging head homogenates of wild-type and mutant flies, calculated to show the average content per head in ng (histamine) or pg (dopamine, 5-HT). The pellet and supernatant fractions were significantly different (paired t-test, P<0.006), but the direction of the difference depended on the genotype. Values are means ± s.d. (B) Same data as in A, shown as the corresponding pellet:supernatant ratio for mutant and wild-type fly brain homogenates. These ratios are inverted for the mutant flies, compared with wild-type flies.