Figure 2

Detection of QPCR-block following exposure of naked gDNA to increasing concentrations of melphalan. The 6.8 kb and 1.6 kb TP53 amplicon PCR products, analysed in triplicate, were separated by gel electrophoresis alongside size markers and visualised by ethidium bromide staining (A,B). The gels were then analysed by densitometry (C,D; grey squares). Parallel analysis of each PCR product was then undertaken using fluorescence spectrophotometry (C,D; green circles). Data are shown as the mean ± standard error across three independent experiments. Curve fits and IC₅₀ values (mean ± standard error) were: 6.8 kb gel densitometry, r² = 0.99, IC₅₀ = 0.256 ± 0.007 µg.mL⁻¹ and 1.6 kb gel densitometry, r² = 0.86, IC₅₀ = 1.088 ± 0.111 µg.mL⁻¹. 6.8 kb fluorescence spectrophotometry, r² = 0.98, IC₅₀ = 0.207 ± 0.017 µg.mL⁻¹, and 1.6 kb fluorescence spectrophotometry, r² = 0.98, IC₅₀ = 0.680 ± 0.076 µg.mL⁻¹. There was no significant difference in the IC₅₀ values obtained by gel densitometry and fluorescence spectrophotometry for either amplicon. Gel images were obtained with an exposure between 0.6–2.7 seconds using Gel Doc^TM EZ Imager (Bio-Rad, USA).