Miniprimers designed and tested. (A) Sequences of miniprimers tested. (B) Performance of miniprimer pairs. Forward and reverse miniprimers were used to PCR amplify 16S rRNA genes from bacterial (Escherichia coli [Ec]) or archaeal (Halobacterium salinarum[Hs]) genomic DNA. PCR was determined successful if a band of the correct size was detected with minimum background. Success or failure with each template is indicated with + or −, respectively, in the appropriate column; a mark of +/− indicates that the product was in low abundance or contained a moderate amount of background but may be clonable. In several cases, amplicons were sequenced to confirm them to be the expected 16S rRNA sequences; confirmation is indicated by a + in the column labeled “16S.” nd, not determined.