2.3 CRISPR / CAST package specificity test
Compare primers and crRNA sequences with Brucella and its cross-strains(Yersinia enterocolitica O:9, Escherichia coli O157, Salmonella enterica serovar Urbana O:30, andFrancisella tularensis ) by BLAST function. The RPA primers and four groups of crRNA alignments were single copies of theBrucella gene, and cross strains have no matching fragments. As mentioned in 1.3.3, the Brucella DNA samples test was positive, negative controls (no RNA enzyme water) and Yersinia enterocolitica O:9, Escherichia coli O157, Salmonella enterica serovar Urbana O:30, and Francisella tularensissamples were all negative (Figure 4). The above results showed that the CRISPR/CAST package could specifically assay target genes in theBrucella DNA samples without cross-reacting with other bacterial nucleic acids, indicating that the assay showed high specificity and that the samples of Yersinia enterocolitica O:9, Escherichia coli O157, Salmonella enterica serovar Urbana O:30, and Francisella tularensis showed no false-positive results.