New double-staining technique for RNA and DNA measurement in marine phytoplankton

Abstract

The use of RNA: DNA ratios as a biochemical indicator is hampered by the lack of simple and reliable methods for routine work. The technique presented here approaches this problem by using 2 fluorochromes: Hoechst 33258, which specifically reacts ~ l t hDN A, and Thiazole Orange, which allows total nucleic acid estimation. Samples dre honlogenized in ~ris-Ca'+ buffer which is also used in the fluorometric analysis. Subsequently, these fluorochromes are added to different subsamples of the same nucleic arid extract. Several extraction and analysis techniques were tested and an optimized procedure is described The technique 1s simple and more sensitive than previously described methods for the determination of RNA and DNA In phytoplankton.