A multi-user phosphorimager is requested by a group of investigators in the Department of Plant Biology and the Center for Agricultural Biotechnology. This instrument is often referred to as a fast, accurate, filmless autoradiography system. It facilitates the rapid and sensitive quantitation of radioactivity on gels or blots without scintillation counting or autoradiography. Highly sensitive storage phosphor screens capture the image of the experimental sample ten times faster than film. The broad linear dynamic range of the phosphoimager permits quantitative detection of both strong and weak signals in a way that film simply cannot. Digital images are compiled and analyzed with a microcomputer. We propose to use this powerful instrumentation in a wide range of applications, including the quantitative analyses of DNA-protein interactions by gel retardation, measurement of transcript levels by RNA gel blots or RNase protection assays, and kinetic measurements of enzyme activity and protein phosphorylation. The acquisition of a phosphorimager will permit us to obtain quantitative information and answers to research questions that would otherwise be impossible to obtain using conventional X-ray film and autoradiography. Six of the seven investigators are currently supported by competitive grants from federal agencies. In all cases, the proposed experiments requiring analyses by the phosphorimager are essential to the long-range goals of understanding the molecular basis for plant pathogenesis, signal transduction, membrane transport and mitosis.
