Is there a starter for qPCR to analyze nxr gene expression? I wanted to study NOB community in activated sludge sample. I have found only one paper where there is a starter for qPCR reaction for NOB (NxrB encoding the beta subunit of nitrite oxireductase as a functional and phylogenetic marker for nitrite-oxidizing Nitrospira) but I cannot find any starter to study gene expression by means of qPCR.