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Measurements of accumulation and displacement at the single cell cluster level in Pseudomonas aeruginosa biofilms
Author(s) -
Klayman Benjamin J.,
Klapper Isaac,
Stewart Philip S.,
Camper Anne K.
Publication year - 2008
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2008.01660.x
Subject(s) - biofilm , pseudomonas aeruginosa , biology , exponential growth , cluster (spacecraft) , biophysics , growth rate , strain (injury) , volume (thermodynamics) , adhesion , displacement (psychology) , microbiology and biotechnology , bacteria , chemistry , anatomy , physics , genetics , thermodynamics , geometry , psychology , mathematics , organic chemistry , quantum mechanics , computer science , psychotherapist , programming language
Summary Quantitative descriptions of biofilm growth and dynamics at the individual cell level are largely missing from the literature. To fill this gap, research was done to describe growth, accumulation and displacement patterns in developing Pseudomonas aeruginosa biofilms. A parent strain of PAO1 was labelled with either a cyan or yellow fluorescent protein. These were then grown in a flow cell biofilm together so that pockets of dividing cells could be identified and their accumulation and displacement tracked. This analysis revealed a pattern of exponential accumulation for all clusters followed by a stationary accumulation phase. A background ‘carpet’ layer of cells uniformly colonizing the surface exhibited zero net accumulation of bio‐volume. The individual clusters were found to have a mean accumulation rate of 0.34 h −1 with a range of 0.28–0.41 h −1 . Cluster accumulation rates were negatively correlated with cluster size; larger clusters accumulated volume at a slower rate ( P < 0.001). Pockets of cells on the inside of clusters initially accumulated at a comparable rate to the cluster within which they resided, but later invariably exhibited zero to slightly negative accumulation despite continued exponential (positive) accumulation of the cluster. Expanding clusters were able to displace neighbouring cells from the surface, and larger clusters displaced smaller clusters. This work provides a more detailed quantitative experimental observation of biofilm behaviour than has been described previously.