Elaine M. Caldarone

Quantitation of DNA and RNA in crude tissue extracts by flow injection analysis

An automated two-dye flow injection analysis system to quantitate DNA and RNA in crude extracts of tissues is described. The method uses the fluorochrome dyes ethidium bromide and Hoechst 33258. DNA concentration is determined directly from its fluorescence in Hoechst dye. RNA is estimated from fluorescence in ethidium bromide after subtraction of the fluorescence due to DNA. This method has several advantages: a simple extraction procedure, a low detection limit (0.01 micrograms DNA and 0.10 micrograms RNA), automation, and a high sample throughput.

Estimating Recent Growth Rates of Atlantic Salmon Smolts Using RNA-DNA Ratios from Nonlethally Sampled Tissues

Abstract Four tissues that can be removed nonlethally were evaluated for their effectiveness in estimating recent growth rates of Atlantic salmon Salmo salar smolts using RNA-DNA ratios (R/Ds). Weight-based growth rates were calculated for smolts reared in the laboratory for 4 weeks. Gill, muscle, scale, and caudal fin tissues were sampled to evaluate sampling ease during fieldwork, the quantity of RNA and DNA available for analysis, and the correlation of R/D with growth rate. Muscle provided adequate tissue for nucleic acid analysis, was strongly correlated with recent growth rates, and could be easily sampled in the field using a biopsy punch. Gill tissue did not provide adequate RNA for analysis with an ethidium-bromide-based microplate fluorometric assay, and R/Ds from scale and fin tissues were poorly correlated with growth rate.