Influence of naturally occurring eDNA and added Ca²⁺ on bacterial aggregation.

<p>Percentage reduction in optical density of Gram-negative and Gram-positive bacteria in PBS, showing patterns of aggregation. The black, white and grey bars represent bacterial aggregation in presence of naturally occurring eDNA, absence of naturally occurring eDNA (DNase I treated) and heat inactivated DNase I treated respectively. Error bars represents standard deviations from multiple cultures (n = 5). Asterisks and hash indicate statistically significant differences (<i>p</i><0.05) between data obtained in the presence (including heat inactivated DNase I) of eDNA in comparison to absence of eDNA and in presence and absence of Ca²⁺ respectively (A). Fluorescence microscopy imaging showing patterns of <i>S. aureus</i> and <i>E. faecalis</i> adhesion and aggregation in presence and absence of eDNA and added Ca²⁺ (1000 μM) on 6 polystyrene well plates surfaces after incubation for 90 min in room temperature under static condition (scale bar 50 μm) (B and C).