The forward primers contain BamHI sites whereas the reverse primers contain SalI sites (bold sequences). PCR was carried out in the following reaction mixture: 10 pmol of each pair of primers, 100 ng of T. cruzi genomic DNA, 200 μM dNTPs, 1.5 mM MgCl2, 20 mM Tris-HCl, pH 8.4, 50 mM KCl and 2.5 units of Taq DNA polymerase (Invitrogen). Reactions were carried out

in a GeneAmp PCR System 9700 (Applied Biosystems) thermal cycler, with an initial denaturation at 94°C for 4 min, followed by 30 cycles of 94°C for 30 s, 58°C for 30 s and 72°C for 30 s. We obtained an amplified product of 0.4 kb for TcKAP4 and 0.65 kb for TcKAP6. The PCR products were purified with a high-purity PCR product purification kit (Roche), digested with BamHI and SalI and inserted into the pQE30 expression vector (QIAGEN). The His6-tagged https://www.selleckchem.com/products/BAY-73-4506.html recombinant proteins were produced in the E. coli M15 strain following Nec-1s in vivo induction SU5402 research buy with 1 mM IPTG (isopropyl-1-thio-β-D-galactopyranoside) and culture for an additional 3 h at 37°C. Purification of recombinant TcKAPs The recombinant proteins

were largely insoluble and were obtained from the inclusion bodies. The pellets of cultures of E. coli expressing TcKAP4 or TcKAP6 (250 ml) were resuspended in 10 ml of 20 mM Tris HCl, pH 8.0, 0.5 M NaCl and subjected to five pulses of sonication for 10 s each at 4°C (Cole Parmer 4710). The sonicated extracts of E. coli were centrifuged at 12,000 × g for 10 min at 4°C. The supernatant was discarded and the pellets containing the inclusion bodies were washed three times in 50 mM Tris-HCl, pH 8.0, 0.5 M NaCl, 2% Triton X-100, resuspended in 4 ml of the protein sample buffer for SDS-PAGE (Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis) and resolved

in 15% polyacrylamide gels (20 cm × 20 cm × 0.4 cm) at 20 volts for 16 h at room temperature. After electrophoresis, the gels were incubated in cold Astemizole KCl (100 mM) for 30 min to visualize the bands of proteins. The recombinant protein bands were excised from the gels, electroeluted in a dialysis bag at 60 V for 2 h in SDS-PAGE buffer and dialyzed against PBS (10 mM sodium phosphate buffer, 150 mM NaCl), pH 8.0. Production of polyclonal antisera Polyclonal antisera against the recombinant proteins were produced in mice. The animals were immunized by intraperitoneal injection with 100 μg of the appropriate antigen in Freund’s complete adjuvant (Sigma) for the first inoculation and with 20 μg of the recombinant protein with Freund’s incomplete adjuvant (Sigma) for three booster injections at two-week intervals. Antisera were obtained five days after the last booster injection. Immunoblotting For immunoblotting analysis, cell lysates (1 × 107 parasites) were separated by SDS-PAGE in 15% polyacrylamide gels and the protein bands were transferred onto a nitrocellulose membrane (Hybond C, Amersham Biosciences) according to standard protocols [33].