SEM analysis of mixed biofilms. Biofilms inhibited by zinc show thick pili (A, C) that are not visualized in biofilms insensible to zinc (B,D). Pili are seen mediating cell-to-cell interaction and adhesion to surface (white arrows). Fimbrial structures resembling curli can be observed in some samples (black arrows).
Mansan-Almeida et al. BMC Microbiology 2013 13:22 doi:10.1186/1471-2180-13-22