PCR amplification products of the 18S rRNA gene obtained after amplification using different primer sets. (a) Primers NS1-Euk and Univ-1390, designed to target the eukaryotic18S rRNA gene. These products were subsequently diluted and used as a template in the following amplification reaction. (b) Primers Neocal-forward and Neocal-reverse, designed to target the Neocallimastigales 18S rRNA gene. Lane 1, GeneRuler 100-bp DNA Ladder Plus (MBI Fermentas); lane 2, Neocallimastix frontalis; lane 3, Rhizopus stolonifera; lane 4, Saccharomyces cerevisiae; lane 5, Cunninghamella elegans; lane 6, bovine rumen fluid.