May 16, 2025
Preparing grape-juice agar plates for Drosophila embryo collections
- 1Department of Biological Sciences, Lehigh University
- Shropshire Lab
Protocol Citation: Alphaxand Njogu, J. Dylan Shropshire 2025. Preparing grape-juice agar plates for Drosophila embryo collections. protocols.io https://dx.doi.org/10.17504/protocols.io.eq2lyqb5evx9/v1
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: May 12, 2025
Last Modified: May 16, 2025
Protocol Integer ID: 218147
Keywords: Drosophila, embryos, fly food, collection, eggs
Abstract
This protocol details the preparation of grape-juice agar plates, yielding 80 to 100 plates in 35 mm petri dishes for the collection of Drosophila embryos. These plates are intended to be affixed to plastic Drosophila bottles (6 oz and 8 oz). For optimal results, we recommend using 8 oz bottles, as their firmer plastic ensures a more secure plate fit. This method is suitable for collecting embryos intended for downstream processing or to count embryos laid from a group of flies. If measuring embryo-lay rates from individual pairs, we recommend starting with this protocol:
Materials
Materials
- Autoclave tape
- Drosophila Agar, Gelidium, 100 MeshGenesee ScientificCatalog #66-104
- diH2O
- Ethanol, 200 ProofKOPTECCatalog #DSP-MD-43
- Petri dish, 35 mm diameter
- Serological pipette tip, 50 mL
- Tegosept, Fly Food PreservativeGenesee ScientificCatalog #20-259
- Welch's 100% Concord Grape Juice
Equipment
- Autoclave
- Media bottle, 1 L
- Erlenmeyer flask, 250 mL
- Graduated cylinder
- Precision balance
- Serological pipette
Protocol materials
Drosophila Agar, Gelidium, 100 MeshGenesee ScientificCatalog #66-104
Tegosept, Fly Food PreservativeGenesee ScientificCatalog #20-259
Ethanol, 200 ProofKOPTECCatalog #DSP-MD-43
Drosophila Agar, Gelidium, 100 MeshGenesee ScientificCatalog #66-104
Ethanol, 200 ProofKOPTECCatalog #DSP-MD-43
Tegosept, Fly Food PreservativeGenesee ScientificCatalog #20-259
Safety warnings
This protocol involves the use of various chemicals and reagents that require careful handling and strict adherence to safety guidelines to ensure safe laboratory practices. Please review the Material Safety Data Sheets (MSDS) for each reagent before beginning the protocol and take appropriate precautions. All steps should be performed while wearing gloves, a lab coat, and eye protection.
Before start
- Sterilize the working surface with 10% bleach and 70% ethanol.
Autoclave agar solution
Autoclave agar solution
42m
42m
Measure the following ingredients using a graduated cylinder and precision balance, and combine in a 1 L media bottle:
- 350 mL diH2O
- 12.5 g Drosophila Agar, Gelidium, 100 MeshGenesee ScientificCatalog #66-104
10m
Loosely cap the media bottle containing the agar/water solution.
Affix a piece of autoclave tape to the top of the bottle.
2m
Place the flask in an autoclave bin filled with tap water.
Autoclave the media bottle containing the agar/water solution at 121 °C for 00:30:00 .
Note
Placing the media bottle in an autoclave bin with a few inches of tap water helps maintain the agar solution's warmth after autoclaving. This extended heat retention provides additional working time for pouring the plates (as described below).
30m
Create grape-juice solution
Create grape-juice solution
10m
10m
While waiting for the autoclave: measure the following ingredients in order using a graduated cylinder and precision balance, and combine in a 250 mL Erlenmeyer flask:
- 0.25 g Tegosept, Fly Food PreservativeGenesee ScientificCatalog #20-259
- 10 mL Ethanol, 200 ProofKOPTECCatalog #DSP-MD-43
- 150 mL Welch's 100% Concord Grape Juice
Swirl the flask to combine.
Note
It is expected that the Tegosept will only partially dissolve.
10m
Prepare work station
Prepare work station
15m
15m
While waiting for the autoclave: align clean 35 mm petri dishes on a clean work surface.
15m
Pour grape-juice agar plates
Pour grape-juice agar plates
47m
47m
Add the contents of the 250 mL flask containing grape juice to 1 L flask. Mix well by swirling until the color of the grape juice is evenly distributed.
Note
When pouring, allow the solution from the 250 mL flask to flow slowly along the inner wall of the 1 L flask. This technique helps prevent bubble formation.
2m
Using a serological pipette with 50 mL tip, distribute the agar-grape-juice solution into 35 mm petri dishes. Fill each plate completely and avoid introducing bubbles to the plates.
Note
Plates containing bubbles are usable; however, flies commonly lay their embryos within the resulting depressions. This can complicate subsequent embryo collection and accurate counts.
5m
Allow the plates to cool at Room temperature .
30m
Once cool, plates are ready to use. To store plates for later, collect into stacks of 25, wrap in cling film, and keep at 4 °C until use. Plates can be stored for up to 2 weeks.
10m