Fig. 5

Proteolytic activity in multi-species communities containing P. gingivalis strains W50, K1A or E8 in serum. a Graph showing proteolytic activity of the multi-species communities containing P. gingivalis strains W50 (open circle), K1A (open triangle) or E8 (filled circle) in serum. The graph shows mean ± SD of three independent biological replicates. b Aliquots (2 µL) from the cultures on day 0 and day 2 were subjected to zymography on gelatin-containing gels stained with Coomassie brilliant blue. All samples were run on the same gel and the image has not been subject to digital enhancement or bands removed by cropping. The original image is available as Additional file 2. c A representative image of bacteria from the multi-species community incubated with FITC-gelatin (green). The insert is a confocal 16S rRNA-FISH image showing the presence of P. gingivalis (red) and P. micra (blue) within the proteolytically-active bacterial clusters. The bar represents 10 µm. Image analysis revealed that 96 ± 1.9% of P. gingivalis cells were present in these clusters