Drosophila Egg Collection and Dechorionation: A Method to Remove the Outermost Egg Layer

– Allow Drosophila に lay eggs overnight onto a dish containing agar supplemented with grape juice に visualize eggs and coated with yeast に encourage flies に mate and lay eggs. To remove the eggs, add distilled water に the dish and gently wipe the surface with a paintbrush. Then pour the mixture through a nylon mesh placed で a plastic bushing に collect the eggs. Soak the eggs で two rounds of 7% bleach に remove the chorion, or protective outer layer, from the embryo. This process is called dechorionation.

The eggs are now stuck に the side of the bushing. Wash them three times with water に remove the bleach. Finally, use a paintbrush に transfer the eggs from the bushing に vials に continue development or for immediate use で an experiment. In the example protocol, we will collect and dechorionate Drosophila eggs under sterile conditions に rear flies with defined microbiota.

– Place nylon mesh into a plastic bushing に prepare the sieve for egg collection. If the same flies will be used the next day, immediately transfer them に a new cage containing freshly yeasted grape juice agar plates. The grape juice plate で the previous cage contains the fruit fly eggs. Remove dead flies with a clean paintbrush, and take caution not に break up the agar. Rinse the agar plate with distilled water and gently brush the eggs from the agar’s surface then pour the slurry over the mesh に collect the eggs.

Sterilize the biosafety cabinet with 70% ethanol then turn on the UV light. Spray all non-biological supplies with 70% ethanol and immediately place them で the biosafety cabinet, then sterilize them with UV light.

– It is critical に ensure that good aseptic technique is practiced when working within or when adding or removing new materials に the biosafety cabinet.

– Transfer the bushing with the eggs into a 120-milliliter specimen cup and slowly pour 90 milliliters of 0.6% sodium hypochlorite solution, or 7% bleach, into the bushing, just below the rim. Using forceps, periodically move the bushing up and down で the solution に resuspend the eggs. Transfer the bushing directly into a second specimen cup pre-filled with 90 milliliters of bleach.

At the end of the second bleach treatment, the eggs should begin に adhere に the sides of the bushing. Discard the bleach and completely rinse the bushing with sterile water. Again, use forceps に resuspend the egg several times during each wash. By the end of the third wash, most eggs should be attached に the side of the bushing.

Using a sterile paintbrush, transfer the eggs from the side of the bushing に the sterile diet. Leave the caps loose に allow oxygen に enter the tube. The transferred eggs will be visible on the surface of the diet.