DNA
Extraction
Materials
needed (per Pair)
1
glass rod
1
100 ml beaker
10
ml pipets
shampoo
meat
tenderizer
toothpicks
Parafilm
Cold
ETOH or isopropanol
55C
Water Bath
40
ml of phase E. coli broth culture or
2 agar plates with E. coli growing on the surface
Protocol:
1.
Working in pairs, pipet 40 ml of the E. coli broth culture or scrap E. coli off
the surface of 1-2 agar plates into 40 ml of DH20 into a clean 100
ml beaker.
2.
Add 8 ml of clear shampoo and two “toothpicks full” of meat tenderizer to the
culture. Cover and seal the top of the beaker with a piece of parafilm. Slowly and carefully swirl the beaker to mix
the 2 solutions. Place the beaker into
the 55-60C water bath and incubate for 10 min.
3. Slowly add cold (the colder the better) ETOH
(or isopropanol) to the side of the baker so that a layer of ETOH form s on the
top of the bacterial mixture.
5. Take the glass rod (make sure it is very
clean) and hold it vertically so that it reaches the bottom of the beaker and
then turn the rod slowly. You should
see a viscous mixture start to stick to the rod at the interface of the ETOH
and bacteria. Gradually increase the
vigor by which you stir the solution.
6. Remove your rod from the solution after you
think the ball has stopped growing. How
big is the ball of DNA? How did it fit
into the bacteria? Is there anything
else sticking to the rod.
7.
Squeeze the DNA ball gently against the inside surface of the beaker until you
are left with a film on the rod and allow to air dry.