Mesoplasma florum:Genomic DNA

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Extraction of genomic DNA from Mesoplasma florum

Culture 10 ml of medium 1161 infected with Mesoplasma florum in two 15 ml centrifuge tubes at 30° without shaking.

Spin down at 3000g for 10 minutes and retain the pellet.

Resuspend the pellet by vortexing first, then adding 1 ml of TE.

Add 3 μl of proteinase-K 20 mg/ml, mix

Add 15 μl of SDS 20% solution

Incubate at 37° for 1 hour

Add 100 μl of 5 M NaCl and mix (critical before adding CTAB)

Add 80 μl of CTAB/NaCl solution, mix

Incubate 10 minutes at 65°

Add an equal volume (1.2 ml) of chloroform/isoamyl alcohol 24:1, vortex and spin down at 7000g for 6 minutes

Remove the supernatent to a fresh tube and add an equal volume of phenol/chloroform/isoamyl alcohol 25:24:1 and mix carefully.

Spin down at 7000g for 6 minutes

Remove the supernatent to a fresh tube and add an equal volume of chloroform/isoamyl alcohol 24:1 and mix carefully.

Spin down at 7000g for 6 minutes

Remove the supernatent to a fresh tube and add 0.6 volumes of isopropanol; DNA should precipitate as a clear/white pearly substance in solution. Hook the DNA with a sterile pasteur pipet, drain, and tranfer to a fresh tube, or alternatively, spin down at high speed and pour off the supernatent.

Fill the tube with 70% ethanol to wash, and spin down at 7000g for 6 minutes.

Remove the ethanol carefully leaving the white pellet. Let the tube air dry for 1/2 hour until the ethanol odor is no longer present

Redissolve the DNA in 100 μl TE (this will take an hour or so). Roll the liquid in tube to wet the entire surface.

Spin down the tube briefly and transfer the DNA to a small tube.

Measure OD and 260/280 ratios.

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