Transcriptome analysis of Pseudomonas aeruginosa growth: comparison of gene expression in planktonic cultures and developing and mature biofilms

Abstract

The transcriptomes of logarithmic- and stationary-phase Pseudomonas aeruginosa planktonic cultures and static biofilms of different stages of development were compared. Developing and confluent biofilm transcriptomes were found to be related to those of logarithmic- and stationary-phase planktonic cultures, respectively. In addition, a number of novel genes were up-regulated in developing and confluent biofilms, including genes encoding putative solute transport proteins and transcriptional regulators, respectively.

FIG. 1.

Confocal laser scanning microscope imaging of nitrocellulose filter biofilms. (A) Single PAO1 bacterial cells tagged with green fluorescent protein (pUCP18 containing gfpmut3*) deposited on the membrane support (time zero). (B) Microcolony development after 2 h. Increase in size of microcolonies with time (4, 6, and 8 h [C, D, and E, respectively]) and formation of a confluent biofilm after 14 h (F) are also shown. Images taken with a Zeiss LSM510 confocal microscope (40× magnification). All six panels show aerial views (x-y planes). Panel F also shows vertical sections through the biofilm (to the right of and above x-y planes).

FIG. 2.

Microarray data experiment tree (drawn using GeneSpring version 5.1 [Silicon Genetics]) with data from six different conditions. LP, log-phase planktonic culture; SP, stationary-phase planktonic culture. Numbers (8, 14, 24, and 48) refer to biofilm at the indicated time points. Coloring: blue, down-regulated; yellow, normal; red, up-regulated.