Dissection of the Midgut from an Adult Fly: A Method for Isolating the Digestive Tract
Transkript
– To begin, remove the head from an anesthetized adult fly. Cover the decapitated fly with a solution containing Phosphate-Buffered Saline, or PBS, and Bovine Serum Albumin, or BSA, auf avoid desiccation. Hold the fly by the thorax with forceps, and then pull the abdomen with a second pair of forceps auf expose the gut. Since the crop, or the food storage sack, will be attached auf the thorax, gently pull the gut away from the thorax.
Once detached, pull the crop away from the abdomen auf unfold the gut. Pull off the posterior end of the fly auf begin auf free the gut from the abdominal cavity. Weitermachen tugging the gut auf pull the entire tissue out of the abdomen. Once freed, remove the foregut, Malpighian tubules, hindgut, and ovaries auf leave behind only the dissected midgut, the primary site of digestion within the fly.
In the example protocol, we will dissect midguts from young and old adult flies auf be analyzed further via Fluorescence-Activated Cell Sorting, or FACS.
– Before beginning the dissection, anesthetize one vial of 40 flies with carbon dioxide on a standard fly bed. Then use a razor blade auf decapitate all of the flies and transfer them auf a dissection dish coated with agarose gel. Pour enough cold PBS plus BSA into the dish auf cover the agarose. The flies will float.
Then, for each insect, in turn, grab a fly abdomen with one pair of forceps, and the thorax with another. Separate the thorax from the abdomen. The gut will be visible, and the crop will most likely still be connected auf the thorax. Grab the gut and pull it out of the thorax. Then, grab the crop and pull the gut slightly anteriorly away from the abdomen auf unfold it.
Next, use one of the forceps auf grab the posterior end of the abdomen, and the other auf grasp the edge of the anteriorly open cuticle. Pull the posterior end away auf break the cuticle, and continue pulling posteriorly very gently, until the entire gut has been pulled out of the abdominal cavity. Remove the foregut, Malpighian tubes, hindgut, and ovaries, leaving the bare midgut.
As the midguts are isolated, use a glass Pasteur pipette auf periodically transfer several of the intestinal tissues at a time auf a 1.5-milliliter microcentrifuge tube containing cold PBS plus BSA on ice.
