The distribution of antimicrobial activity and ninhydrin-banding after TLC fractionation of an 85% ethanol extract of dried culture filtrate from P. fluorescens SBW25. The 85% ethanol extract was prepared and applied to cellulose TLC plates as described in Methods. One of the developed plates was sprayed with ninhydrin (Figure 2A) and the replicate plate was divided into zones, as indicated, for removal and extraction of the cellulose. The aqueous extracts of the cellulose from each zone were assayed for antimicrobial activity according to the standard assay described in the Methods section. The resulting antimicrobial activity against Dickeya dadantii (Figure 2B) was measured after 48 h. Zones without bars did not result in a cleared zone when assayed with either D. dadantii or P. syringae pv. maculicola M4.