For each amplification of the fucA1 gene was used $2500fold more cDNA than that used for the amplification of the 16S rRNA. Controls with no template cDNA were always included. PCR conditions were 15 min at 95 C for initial denaturation, followed by 40 cycles of 10 s at 95 C, 25 s at 56 C and 35 s at 72 C, and a final step of 10 min at 72 C. Product purity was controlled by melting point analysis of setpoints with 0.5 C temperature increase from 72 to 95 C. PCR products were analysed on 2% agarose gels and visualized by ethidium bromide staining.