Journal: PLoS ONE
Article Title: A Single-Stranded DNA Aptamer That Selectively Binds to Staphylococcus aureus Enterotoxin B
Figure Lengend Snippet: APT SEB1 is selective for SEB within a complex mixture. The toxin-rich cell-free culture supernatant from four S. aureus strains was assayed for the presence of SEB by aptamer-precipitation. Five microliters of each culture supernatant was loaded onto an 4–12% SDS-PAGE gel to determine the protein content (lanes 2, 4, 6, 8). Three milliliters of each culture supernatant was incubated with APT SEB1 -coated Dynabeads. After washing with PBS-T, the resultant protein eluate from the APT SEB1 -coated Dynabeads was analyzed (lanes 3, 5, 7, 9). By PCR and ELISA analysis (Sandra Tallent, personal communication) the four strains potentially express a total of 17 enterotoxins and toxic shock syndrome toxin. However, only strain BAA1747 contains the gene for SEB. The protein bands labeled as “SA” represent the monomer of streptavidin liberated by the elution protocol.
Article Snippet: Following conjugation and washing, the SEB-coated magnetic beads were suspended at 6.7×105 beads/µl, or 10 µg/µl, in PBS-T (10 mM phosphate buffer, 2.7 mM KCl, 140 mM NaCl, 0.05% Tween, pH 7.4, Sigma, St. Louis, MO).
Techniques: SDS Page, Incubation, Polymerase Chain Reaction, Enzyme-linked Immunosorbent Assay, Labeling