Stress responses go three dimensional - the spatial order of physiological differentiation in bacterial macrocolony biofilms.

TitleStress responses go three dimensional - the spatial order of physiological differentiation in bacterial macrocolony biofilms.
Publication TypeJournal Article
Year of Publication2014
AuthorsSerra, DO, Hengge, R
JournalEnviron Microbiol
Volume16
Issue6
Pagination1455-71
Date Published2014 Jun
ISSN1462-2920
KeywordsAdaptation, Physiological, Anti-Bacterial Agents, Biofilms, Escherichia coli, Extracellular Matrix, Humans, Metabolic Networks and Pathways, Second Messenger Systems, Sigma Factor, Stress, Physiological
Abstract

In natural habitats, bacteria often occur in multicellular communities characterized by a robust extracellular matrix of proteins, amyloid fibres, exopolysaccharides and extracellular DNA. These biofilms show pronounced stress resistance including a resilience against antibiotics that causes serious medical and technical problems. This review summarizes recent studies that have revealed clear spatial physiological differentiation, complex supracellular architecture and striking morphology in macrocolony biofilms. By responding to gradients of nutrients, oxygen, waste products and signalling compounds that build up in growing biofilms, various stress responses determine whether bacteria grow and proliferate or whether they enter into stationary phase and use their remaining resources for maintenance and survival. As a consequence, biofilms differentiate into at least two distinct layers of vegetatively growing and stationary phase cells that exhibit very different cellular physiology. This includes a stratification of matrix production with a major impact on microscopic architecture, biophysical properties and directly visible morphology of macrocolony biofilms. Using Escherichia coli as a model system, this review also describes our detailed current knowledge about the underlying molecular control networks - prominently featuring sigma factors, transcriptional cascades and second messengers - that drive this spatial differentiation and points out directions for future research.

DOI10.1111/1462-2920.12483
Alternate JournalEnviron. Microbiol.