Preheat oven to 375 degrees. Grease muffin cups or use paper muffin liners. Mix together wheat bran and milk, and let stand for 10 minutes. (I didn't do this and muffins turned out fine.). In a large bowl, mix together applesauce, egg, brown sugar, and vanilla. Beat in bran mixture. Sift together all-purpose flour, whole wheat flour, baking soda, baking powder, and salt. Stir into bran mixture until just blended. Fold in blueberries. Scoop into muffin cups. Bake in preheated oven for 15 to 20 minutes, or until tops spring back when lightly tapped.