2.2. DNA extraction
The single colonies were inoculated overnight in 10 mL of MYP
broth (37 C). Then, 1 mL of this bacterial culture was centrifuged
for 2 min at 8000 g and washed with 500 mL of sterile distilled
water. The washed bacterial cells were re-suspended in 500 mL
glucose-tris-ethylenediamine tetraacetic acid buffer, followed by
1 h incubation. Then, 25 mL of 10% sodium dodecyl sulfate (w/v) and
25 mL of proteinase K were added to the incubated cells. The
mixture was gently mixed for 1 h and incubated at 65 C for
complete lysis of the cells. After incubation, phenol-chloroformisoamyl
alcohol was added to an equal volume of each mixture
and was gently mixed for 5 min. The samples were centrifuged for
20 min at 12,000 g to create two phases for separation from each
other. The upper phase was transferred to the clean tube and equal
volume of isopropanol and 0.1 volume of sodium acetate (3 M)
were added. The samples were incubated for 20 min at 20 C and
then centrifuged at 12,000 g for 15 min at 4 C. The genomic
precipitated DNA plate was air-dried and dissolved in 50 mL DNasefree
water by adding 5 mL RNase for each sample.