Figure 1.
Scanning electron micrographs of mature mixed biofilms of C. albicans and S. mutans grown on extracted human teeth, demonstrating the tight coadherence between C. albicans hyphae (red arrows) and S. mutans cells (blue arrows).
Microbial cells can be seen embedded in a matrix of extracellular polymeric substance with water channels (white arrows) through which liquid flows distributing nutrients and signaling molecules that facilitate communication between the cells. Bars 10 µm.
Figure 2.
Scanning electron micrographs of mature mixed biofilms formed on discs of hydroxyapatite (a major component and essential ingredient of normal teeth), demonstrating the affinity of S. mutans to the hyphal elements of C. albicans.
Bacterial cells are seen attached in chains as they adhere to and wrap around the hyphae. Perforations can be seen in the hydroxyapatite surface (white arrows), possibly the result of decalcification of the material due to the high acidic environment. Bars 10 µm.