Interspecies competition in oral biofilms mediated by Streptococcus gordonii extracellular deoxyribonuclease SsnA

Autor: Nadia Rostami, Robert C. Shields, Hannah J. Serrage, Catherine Lawler, Jane L. Brittan, Sufian Yassin, Halah Ahmed, Achim Treumann, Paul Thompson, Kevin J. Waldron, Angela H. Nobbs, Nicholas S. Jakubovics
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: npj Biofilms and Microbiomes, Vol 8, Iss 1, Pp 1-13 (2022)
Druh dokumentu: article
ISSN: 2055-5008
DOI: 10.1038/s41522-022-00359-z
Popis: Abstract Extracellular DNA (eDNA) is a key component of many microbial biofilms including dental plaque. However, the roles of extracellular deoxyribonuclease (DNase) enzymes within biofilms are poorly understood. Streptococcus gordonii is a pioneer colonizer of dental plaque. Here, we identified and characterised SsnA, a cell wall-associated protein responsible for extracellular DNase activity of S. gordonii. The SsnA-mediated extracellular DNase activity of S. gordonii was suppressed following growth in sugars. SsnA was purified as a recombinant protein and shown to be inactive below pH 6.5. SsnA inhibited biofilm formation by Streptococcus mutans in a pH-dependent manner. Further, SsnA inhibited the growth of oral microcosm biofilms in human saliva. However, inhibition was ameliorated by the addition of sucrose. Together, these data indicate that S. gordonii SsnA plays a key role in interspecies competition within oral biofilms. Acidification of the medium through sugar catabolism could be a strategy for cariogenic species such as S. mutans to prevent SsnA-mediated exclusion from biofilms.
Databáze: Directory of Open Access Journals