Analysis of spatial variability within mot+and mot−pseudomonas fluorescensbiofilms using representative elements

Abstract

The spatial variability for most measurable parameters contained within biofilms is very large. Therefore a procedure for determining statistically representative regions of analysis is desirable. Scanning confocal laser microscopy, a computer‐controlled xy stage, and fluorescence exclusion staining were used to obtain a series of optical thin sections of biofilms formed by motile (mot+) and nonmotile (mot−) Pseudomonas fluorescens on the surfaces of glass flow cells. Based on a representative elementary area (REA) analysis procedure, the images were used to construct montages large enough to encompass the range of variation in biofilm cell area. The minimum area of analysis required to be representative varied with depth in the biofilm and between the strains used. Biofilms consisting of mot− P. fluorescens were variable. Thus, large area (REA ≥ × 105‐μm−) were required for statistically valid comparisons of cell distribution. REAs for the mot+ biofilm reflected a more uniform distribution of cells at al...