Fig. 2. Twenty-four and forty-eight hour biofilms of C. albicans (Ca) alone or with wild-type S. oralis (So34), gtfR mutant (So ∆gtfR) or complemented (So pgtfR) strains.

Biofilms were grown on polystyrene surfaces in RPMI, 10% FBS, 10% BHI media supplemented with 1% sucrose. a X–Y isosurfaces (top panel) and three-dimensional reconstructions (bottom panel) of representative confocal laser scanning microscopy images of biofilms. Please note overlap of green and red signals shown in yellow, suggesting close physical proximity between the two organisms. Scale bars 50 μm. b Average total biofilm biovolume (in µm³) for 24 and 48 h biofilms. c S. oralis CFU counts expressed as fold of mixed over single biofilms. d Average matrix biovolumes (in µm³). e Relative expression of gtfR gene levels assessed by RT-qPCR. Results represent mean fold change gene expression in C. albicans with S. oralis (CaSo, black bars) over S. oralis (So, white bars) biofilms alone, in three independent experiments. f C. albicans CFU counts expressed as fold of mixed biofilms with each of the three S. oralis strains (CaSo) over single biofilms (Ca). *p < 0.05, using the Bonferroni t-test. The error bars indicate standard deviations.