1. Scanning electron micrographs of P. fluorescens biofilms.
Scanning electron micrographs of P. fluorescens biofilms. For these photomicrographs, Baum et al. prepared and cryopreserved 14-day biofilms from P. fluorescens EvS4-B1 monocultures (56). (A) Fibrillary structures made up of twisted fibers (arrow). Bar = 1 μm. (B) Flat sheets of material (arrowheads), with some of the sheets wrapped around other structures (arrow). Bar = 20 μm. (C) The inside core of the “wrapped” structures, consisting of bacteria (B) embedded in an extracellular matrix of particulate matter, and a thin sheet of material (arrow). Bar = 1 μm. (D) The outer sheet (arrowheads), which envelops an inner core consisting of fibers forming irregular network-like structures (arrows). Bar = 10 μm. (E) Network consisting of fibers arranged in a periodic pattern, with bacteria (arrows) dispersed throughout the network. Bar = 2 μm. (F) A sheet of material (S), consisting of extracellular material and dead cells, covering and attaching to the fiber network and including associated bacteria (B) and particulate matter (P). Bar = 2 μm. (Reprinted from BMC Microbiology [56] under a Creative Commons license [
Brittan S. Scales et al. Clin. Microbiol. Rev. 2014; doi: /CMR