Results of PCR1 (a) and PCR2 (b) on whole bacterial RNAs lanes: 1, 10 fg of E. coli DNA; 2, 50 ng of E. coli total RNA, no reverse transcription; 3, 50 ng of E. coli RNA reverse transcribed to cDNA; 4, 50 ng of M. tuberculosis total RNA, reverse transcribed to cDNA. Amplification products from PCR1 and PCR2 were visualized on a 2.0% agarose gel, transferred to nylon membranes using standard techniques, and then hybridized with 32P-labeled MTG-specific PCR2 amplification product using M. tuberculosis genomic DNA as template.