FIG. 4.

Bacterial invasion of one- and four-species biofilms by Pseudoalteromonas tunicata. Biofilms composed of one or four strains of the epiphytic isolates, Microbacterium phyllosphaerae, Shewanella japonica, Dokdonia donghaensis, and Acinetobacter lwoffii, were established in glass flow cells inoculated with equal total cell densities. After 2 h of growth in the presence of medium flow, the antibacterial protein-producing P. tunicata was introduced to the biofilms. This strain constitutively expressed green fluorescent protein. At various time points, the fraction of the surface covered by P. tunicata biofilm was determined by staining of the biofilm cells followed by confocal laser scanning microscopy, image analysis, and comparisons to corresponding biofilms not subjected to P. tunicata invasion. This is presented as “percentage invasion by Pseudoalteromonas tunicata”. Bars represent means ± standard errors for eight replicates.