Fly lab protocols and recipes
Nutrient-rich fly medium
Nutrient-rich fly medium
8 g agar
80 g cornmeal
18 g dried yeast
Live baker’s yeast
80 g malt extract
7 g molasses
6.3 mL propionic acid
10 g soybean meal
Dissolve ingredients (except propionic acid and live baker’s yeast) in 1 L of H2O. Boil
extensively on a hot plate until all ingredients are well dissolved. Add the propionic
acid (a mold inhibitor). Pour the medium into 175-mL bottles, and allow it to solidify.
Add a large drop of live baker’s yeast on the surface of the medium in each bottle.
Ringer’s solution (pH 7.3-7.4)
Reagent
Amount to add
NaCl
7.2 g
CaCl2
0.17 g
KCl
0.37 g
Dissolve all reagents into reagent-grade H2O, and bring the final
volume to 1 L. Adjust the pH to 7.3-7.4. Once thoroughly dissolved,
filter through a 0.22-μm filter, aliquot into single-use volumes (25-50
mL), and autoclave.
Phosphate-buffered saline (PBS)
Amount to
add
(for
Amount
Final
1Xconcentration
to
addFinal
(for
10Xconcentration
Reagent
solution)
(1X)
stock)
(10X)
NaCl
8g
137 mM
80 g
1.37 M
KCl
0.2 g
2.7 mM
2g
27 mM
Na2HPO4
1.44 g
10 mM
14.4 g
100 mM
KH2PO4
0.24 g
1.8 mM
2.4 g
18 mM
If necessary, PBS may be supplemented with the following:
CaCl2•2H2O
0.133 g
MgCl2•6H2O 0.10 g
1 mM
1.33 g
10 mM
0.5 mM
1.0 g
5 mM
PBS can be made as a 1X solution or as a 10X stock. To prepare 1 L of
either 1X or 10X PBS, dissolve the reagents listed above in 800 mL of
H2O. Adjust the pH to 7.4 (or 7.2, if required) with HCl, and then add
H2O to 1 L. Dispense the solution into aliquots and sterilize them by
autoclaving for 20 min at 15 psi (1.05 kg/cm2) on liquid cycle or by
filter sterilization. Store PBS at room temperature.
Phosphate-buffered saline (PBS), RNase-free
Phosphate-buffered saline (PBS)
Before autoclaving the PBS, add 1 mL of DEPC (diethyl pyrocarbonate) to 1 L of
PBS and shake vigorously. Then, autoclave for 20 min on liquid cycle to sterilize the
solution and inactivate the DEPC.
RNase-free PBS can also be purchased as a 1X solution or a 10X stock from a variety
of sources.
Grape juice agar
MATERIALS
Reagents
24.0 g Bacto Agar
26.4 g sucrose
200 mL grape juice (100%)
g methylparaben
20 mL ethanol (95%)
Equipment
Beaker (large)
Microwave oven
Vials or plates (plastic)
METHOD




1. Mix Bacto Agar and 800 mL water. Microwave until the agardissolves
completely (take care to prevent overflowing). Remove the solution from
the microwave.
2. Stir in sucrose and grape juice, and allow it to cool to 50°C.
3. Dissolve methylparaben in 95% ethanol, and add to the agarsolution.
Stir well.
4. Pour into plastic vials or plates (we typically use lids of Petri dishes), as
desired. Let the agar cool and solidify before storing or using.