FIG. 1.

PCR amplification to test the sensitivity of both primer pairs amplifying the PC internal transcribed spacer region (PC) and a microcystin-specific region (the mcyB gene) (MC) for a microcystin-producing Microcystis sp. strain HUB 5-2-4 dilution series. In addition, the specificity of both primer pairs and the potential impact of a natural background were tested in parallel. The numbers above the lanes refer to template DNA (equivalent to 10,400 to 1.04 cells) in the presence or absence of a natural background from Lake Wannsee. For details on the preparation of the natural background, see the text. Lane M, molecular weight markers, in base pairs; lane NTC, nontemplate control.