Figure 4.

The effects of DNase I or proteinase K on the ability of Hrr. lacusprofundi to form biofilms. Cells grown in the absence of DNase I or proteinase K (A); 10 μg mL⁻¹ DNase I (B); 100 μg mL⁻¹ DNase I (C); 0.1 μg mL⁻¹ proteinase K (D); 1 μg mL⁻¹ proteinase K (E); 10 μg mL⁻¹ proteinase K (F). Biofilms captured on filter papers for each enzyme treatment (25 mL medium, 100 mL flask) are shown beside their respective flasks. The scanning electron microscopy scale bar represents 1 μm. (A,B,C) Increasing the concentration of DNase I reduced the extent of extracellular lattice network present between cells. (D,E,F) Increasing the concentration of proteinase K led to collapse of the integrity of extracellular material, and changes in cell morphology and number of viable cells.