Influence of dehydration and associated centrifugation steps prior to FISH hybridization on cell counts. The bar charts represented the cell counts for E. coli cultures and UASS biogas reactor samples with (black bars) and without (white bars) dehydration steps during the FISH procedure. All samples were pretreated with purification procedure 1-C2-S2-H1-F2. Error bars resulted from nine different measurements with Coulter Counter. In case of UASS sample with dehydration step (black) only three measurements were conducted.