Severalnewoptionsforpossibleprimerswerefound
whenthenirSsequenceswerealigned(Table3;Fig.1a).
Theyarealllocatedinthesecondhalfofthegene,where
the majority of the sequences have been derived. Un-
fortunately, there are only nine complete nirS gene se-
quencesinthedatabases.ForseveralnirSprimers,small
modificationsweretested,butinTable1onlytheresults
fromthebestprimertargetingeachprimersiteisshown.
The bestresultwas obtainedwiththe modified version
ofprimercd3F[11]cd3aFincombinationwiththenirS