Analysis of the major capsid protein gene by PCR, using the MCPF5/R5 primer pair. Twenty microliters of the PCR products was run on a 1.2% agarose gel, which was subsequently stained with ethidium bromide. Cyanophage strains: AN-15 (lane 1), A-1 (L) (lane 2), and N-1 (lane 3). Virus concentrates collected from freshwater lakes, with the date of collection (day/month/year) and DNA extraction method (p, phenol; c, CTAB): Priest Pot 260302 (p) (lane 4), Priest Pot 090402 (p) (lane 5), Priest Pot 230402 (p) (lane 6), Priest Pot 080502 (p) (lane 7), Priest Pot 210502 (p) (lane 8), Priest Pot 180602 (p) (lane 9), Priest Pot 160702 (p) (lane 10), Priest Pot 130802 (p) (lane 11), Priest Pot 100904 (p) (lane 12), Priest Pot 081002 (p) (lane 13), Priest Pot 210502 (c) (lane 14), Priest Pot 180602 (c) (lane 15), Esthwaite 160702 (p) (lane 16), Esthwaite 130802 (p) (lane 17), and negative control (lane 18). The positions of the λ Pst markers are labeled on the right-hand side of the gel.