Utility of green fluorescent nucleic acid dyes and aluminum oxide membranefilters for rapid epifluorescence enumeration of soil and sediment bacteria

High background fluorescence and unspecific staining hampered the epifluore scence enumeration of bacteria in 45% of the tested soil and sediment sampl es with 4',6-diamidino-2-phenylindole (DAPI) and polycarbonate membrane fil ters. These problems of the determination of total cell counts can be circu mvented by using green fluorescent high-affinity nucleic acid dyes and alum inum oxide membrane filters. Due to the bright staining of cells, we recomm end SYBR Green II as dye.