Microanatomy at Cellular Resolution and Spatial Order of Physiological Differentiation in a Bacterial Biofilm

Abstract

Heterogeneity or cellular differentiation in biofilms is a commonly accepted concept, but direct evidence at the microscale has been difficult to obtain. Our study reveals the microanatomy and microphysiology of an Escherichia coli macrocolony biofilm at an unprecedented cellular resolution, with physiologically different zones and strata forming as a function of known global regulatory networks that respond to biofilm-intrinsic gradients of nutrient supply. In addition, this study identifies zones of heterogeneous and potentially bistable CsgD and curli expression, shows bacterial curli networks to strikingly resemble Alzheimer plaques, and suggests a new role of flagella as an architectural element in biofilms.