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A Critical Role for Extracellular DNA in Dental Plaque Formation

Lookup NU author(s): Dr Nadia Rostami, Professor Alastair Hawkins, Dr Richard HollidayORCiD, Professor Philip Preshaw, Professor Nicholas JakubovicsORCiD



This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).


Extracellular DNA (eDNA) has been identified in the matrix of many different mono-species biofilms in vitro, including some of those produced by oral bacteria. In many cases, eDNA stabilizes the structure of mono-species biofilms. Here, we aimed to determine whether eDNA is an important component of natural mixed-species oral biofilms such as plaque on natural teeth or dental implants. To visualize eDNA in oral biofilms, approaches for fluorescently staining eDNA with either anti-DNA antibodies or an ultrasensitive cell-impermeant dye, YOYO-1, were first developed using E. faecalis, an organism that has previously been shown to produce extensive eDNA structures within biofilms. Oral biofilms were modelled as in vitro ‘microcosms’ on glass coverslips inoculated with the natural microbial population of human saliva and cultured statically in artificial saliva medium. Using antibodies and YOYO-1, eDNA was found to be distributed throughout microcosm biofilms, and was particularly abundant in the immediate vicinity of cells. Similar arrangements of eDNA were detected in biofilms on crowns and overdenture abutments of dental implants that had been recovered from patients during the restorative phase of treatment, and in subgingival dental plaque of periodontitis patients, indicating that eDNA is a common component of natural oral biofilms. In model oral biofilms, treatment with a DNA-degrading enzyme, NucB from Bacillus licheniformis, strongly inhibited the accumulation of biofilms. The bacterial species diversity was significantly reduced by treatment with NucB and particularly strong reductions were observed in the abundance of anaerobic, proteolytic bacteria such as Peptostreptococcus, Porphyromonas and Prevotella. Pre-formed biofilms were not significantly reduced by NucB treatment, indicating that eDNA is more important or more exposed during the early stages of biofilm formation. Overall, these data demonstrate that dental plaque eDNA is potentially an important target for oral biofilm control.

Publication metadata

Author(s): Rostami N, Shields RC, Yassin SA, Hawkins AR, Bowen L, Luo TL, Rickard AH, Holliday R, Preshaw PM, Jakubovics NS

Publication type: Article

Publication status: Published

Journal: Journal of Dental Research

Year: 2017

Volume: 96

Issue: 2

Pages: 208-216

Print publication date: 01/02/2017

Online publication date: 21/10/2016

Acceptance date: 04/10/2016

Date deposited: 19/10/2016

ISSN (print): 0022-0345

ISSN (electronic): 1544-0591

Publisher: Sage Publications Ltd


DOI: 10.1177/0022034516675849


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