BCECF-labelled bacteria (4 · 108 cells) were allowed to react
with S-Br in 200 ll buffered KCl at 37C for 3 h. After incubation,
the bracket was rinsed three times with buffered KCl and
the fluorescence intensity associated with the S-Br was determined
using a multi-label counter.The number of bacteria bound was
determined using a standard plot of the number of bacterial
cells against the fluorescence intensity.