Figure 6.

Overexpression of tfbE results in biofilm formation. Phase contrast microscopy (oil immersion, × 100) of WT H. salinarum NRC-1 illustrates its typical cellular morphology in liquid cultures (A). In contrast, overexpression of tfbE resulted in formation of white flocculent structures in liquid cultures that were discovered to be because of cell clumping (B). Addition of DNase I to culture media had no effect on the WT but resulted in disassembly of these clumps, suggesting that DNA is a major component of the matrix that holds cells together within the clumps (C: NRC-1+DNase ( × 100); D: P_fer-tfbE/NRC-1+DNase ( × 100).