The tv44 gene expression is down-regulated by low iron. A. Ethidium bromide-stained agarose gels after electrophoresis of RT-PCR products for the tv44 transcript in parasites grown in normal medium (lane 1) or in low- (lane 2) versus high-iron (lane 3) medium. The bottom panel shows the RT-PCR products for the T. vaginalis α-tubulin (α-tub) gene as a control to show equal amounts of RNA in the PCR reactions. B. Immunoblot detection by mAb 6B8 of a 44-kDa protein after SDS-PAGE and blotting as described in the legend of Figure 1 of total proteins derived from trichomonads grown in normal medium (lane 1) and high- (lane 2) versus low-iron (lane 3) medium, as indicated. Numbers on the right are molecular weight standards in kilodaltons (× 1000).