Reverse transcriptase PCR of urease operon. Ethidium bromide stained agarose gel showing results of reverse transcriptase PCR with H. influenzae strain 11P6H. Lanes: a) purified RNA with reverse transcriptase and Taq DNA polymerase; b) purified RNA with Taq DNA polymerase (negative control); c) purified DNA with Taq DNA polymerase (positive control). Lane H2O is a water control. Oligonucleotide primers were designed to span adjacent genes in the gene cluster as noted at the top of the gel (See Table 1). Molecular size markers are noted in base pairs on the right.