A Combined Enrichment and Aptamer Pulldown Assay for Francisella tularensis Detection in Food and Environmental Matrices
Figure 3
DNA aptamers against F. tularensis specifically capture F. tularensis in mixed bacteria samples.
A biotinylated aptamer cocktail composed of 10 aptamers (0.4 pmol each) was bound to M-280 streptavidin Dynabeads. F. tularensis (1–106 cells/mL) was separately mixed with A) 109 CFU/mL of soil bacteria or B) lettuce bacteria and aptamer cocktail beads or control beads (beads without aptamers) and incubated for 1 h at room temperature. Samples were denatured and the supernatant was subjected to real-time PCR analysis. Bead controls showed Cp values greater than 34 and were considered negative for F. tularensis. Legend: Aptamers = black bar, Aptamers and Soil Bacteria = dark grey bar.