FIG. 3.

Determination of the sensitivity of cyanophage-specific PCR primers CPS1 and CPS2. Serial dilutions of a filtered (pore size, 0.2 μm) cyanophage strain S-BnM1 lysate were enumerated by TOTO-1 iodide staining and were amplified in the absence of competitor DNA. Lanes 1 to 6, preparations containing ca. 1.9 × 10⁶, 1.9 × 10⁵, 1.9 × 10⁴, 1.9 × 10³, 190, and 19 cyanophage strain S-BnM1 particles per reaction mixture, respectively. A 15-μl aliquot of each PCR mixture was electrophoresed on a 1.2% agarose gel in 1× TBE buffer.