2.3. Molecular identification by DNA amplification and gene
sequencing
All isolates were cultured on nutrient agar, and genomic
DNA was obtained using the protocol described by Van
Soolingen et al. [44]. Strains belonging to the Bacillus brevis
group and Bacillus aneurinolyticus group were identified by
16S rRNA gene amplification by using specific detection
primers and PCR. The sequences of forward detection
primers BREV174F and ANEU506F were 50-AGACCGGGA
TAACATAGGGAAACTTAT-30 and 50-GAACCGCCGGGATGACC
TCCCGGTC-30 , respectively, and the sequence of reverse
primer 1377R was 50-GGCATGCTGATCCGCGATTACTAGC-30
[45]. PCR was performed in reaction mixtures containing
50 to 100 ng of genomic DNA, 2 U of Taq polymerase
(Invitrogen), 0.2 mM of dNTP mix (GE Healthcare), and 0.4
mM each primer (forward and reverse) in a final volume of
50 mL. Amplification program consisted of an initial denaturation
step at 94 C for 30 seconds, followed by 25 cycles
of 94 C/1 minute, 58 C/1.5 minutes, and 72 C/1.5 minutes,
with final extension of 72 C/5 minutes, in an Eppendorf
thermal cycler (Eppendorf).