<P> It may also be used in conjunction with fluorescence microscopy to stain for the presence of polyhydroxybutyrate granules in prokaryotic or eukaryotic cells . Boiling a solution of Nile blue with sulfuric acid produces Nile red ( Nile blue oxazone ) . </P>
nile blue can be used to test for the presence of
polyhydroxybutyrate granules in prokaryotic or eukaryotic cells