A, digested patterns for the 16S rDNA fragment from bacterial strains (HgR), Bacillus sp. AZ-1, B. cereus AZ-2, B. cereus AZ-3 and E. cloacae ZN-15 (HgS) (Lane M, size markers of 100 bp plus DNA Ladder; Lane 1, 1543bp PCR product of 16S rDNA fragment; Lanes 2-5, digested patterns of the 16S rDNA fragments by EcoR1; Lanes 6-9, digested patterns of the 16S rDNA fragments by Taq1); B, digested patterns for the merA gene from bacterial strains (HgR), Bacillus sp. AZ-1, B. cereus AZ-2 and B. cereus AZ-3 (Lane M, size markers of 100bp plus DNA Ladder; Lane 1, 1289bp PCR products of merA gene; Lanes 2-4, digested patterns of the merA gene by HinF1; Lanes 5-7, digested patterns of the merA gene by HaeIII).