Figure 4

Sensitivity of detection in a complex mixture. Sensitivity of detection of Blepharisma from a complex mixture of protozoa immobilised on FTA paper. Lanes denoted M contain molecular size markers – figures refer to sizes in base pairs. Amplified products from a range of areas of FTA paper were loaded on the gel. These areas contained the following equivalent number of Blepharisma cells: 2.48 cells (lane 3), 1.24 cells (lane 4), 0.62 cells (lane 5). The amplification products run in lane 6 contained the same area of FTA paper as in lane 4 except that they were taken from the mixed culture of protozoa which did not contain Blepharisma. Lane 1 contained pure Blepharisma DNA, immobilised on FTA paper, as a positive control for the PCR reaction while Lane 2 contained Paramecium caudatum DNA, on FTA paper, as a negative control. Larger areas of FTA paper (eg lane 3) consistently inhibited the PCR reaction.