Multiple holins contribute to extracellular DNA release in Pseudomonas aeruginosa biofilms

Hynen, A. L., Lazenby, J. J., Savva, G. M., McCaughey, L. C. , Turnbull, L., Nolan, L. M. and Whitchurch, C. B. (2021) Multiple holins contribute to extracellular DNA release in Pseudomonas aeruginosa biofilms. Microbiology, 167(2), 000990. (doi: 10.1099/mic.0.000990) (PMID:33400641) (PMCID:PMC8131026)

Abstract

Bacterial biofilms are composed of aggregates of cells encased within a matrix of extracellular polymeric substances (EPS). One key EPS component is extracellular DNA (eDNA), which acts as a ‘glue’, facilitating cell–cell and cell–substratum interactions. We have previously demonstrated that eDNA is produced in Pseudomonas aeruginosa biofilms via explosive cell lysis. This phenomenon involves a subset of the bacterial population explosively lysing, due to peptidoglycan degradation by the endolysin Lys. Here we demonstrate that in P. aeruginosa three holins, AlpB, CidA and Hol, are involved in Lys-mediated eDNA release within both submerged (hydrated) and interstitial (actively expanding) biofilms, albeit to different extents, depending upon the type of biofilm and the stage of biofilm development. We also demonstrate that eDNA release events determine the sites at which cells begin to cluster to initiate microcolony formation during the early stages of submerged biofilm development. Furthermore, our results show that sustained release of eDNA is required for cell cluster consolidation and subsequent microcolony development in submerged biofilms. Overall, this study adds to our understanding of how eDNA release is controlled temporally and spatially within P. aeruginosa biofilms.

• Item Type: Articles
• Additional Information: G. M. S. was supported by a BBSRC Core Capability Grant (BB/ CCG1860/1), L. C. M. was supported by a Sir Henry Wellcome Postdoctoral Fellowship (106064/Z/14/2), L. M. N. was supported by an Imperial College Research Fellowship (ICRF) and a Cystic Fibrosis Trust Venture Innovation Award (VIA 070) and C. B. W. was supported by a BBSRC Institute Strategic Programme Grant (BB/R012504/1).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: MCCAUGHEY, Dr LAURA
• Authors: Hynen, A. L., Lazenby, J. J., Savva, G. M., McCaughey, L. C., Turnbull, L., Nolan, L. M., and Whitchurch, C. B.
• College/School: College of Medical Veterinary and Life Sciences > School of Life Sciences
• Journal Name: Microbiology
• Publisher: Microbiology Society
• ISSN: 1350-0872
• ISSN (Online): 1465-2080
• Published Online: 05 January 2021
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Microbiology 167(2): 000990
• Publisher Policy: Reproduced under a Creative Commons License