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Conserved Pheromone Production, Response and Degradation by Streptococcus mutans

Streptococcus mutans, a bacterium with high cariogenic potential, coordinates competence for natural transformation and bacteriocin production via the XIP and CSP pheromones. CSP is effective in inducing bacteriocin responses but not competence in chemically defined media (CDM). This is in contrast...

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Autores principales: Ricomini Filho, Antonio Pedro, Khan, Rabia, Åmdal, Heidi Aarø, Petersen, Fernanda C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6753979/
https://www.ncbi.nlm.nih.gov/pubmed/31572344
http://dx.doi.org/10.3389/fmicb.2019.02140
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author Ricomini Filho, Antonio Pedro
Khan, Rabia
Åmdal, Heidi Aarø
Petersen, Fernanda C.
author_facet Ricomini Filho, Antonio Pedro
Khan, Rabia
Åmdal, Heidi Aarø
Petersen, Fernanda C.
author_sort Ricomini Filho, Antonio Pedro
collection PubMed
description Streptococcus mutans, a bacterium with high cariogenic potential, coordinates competence for natural transformation and bacteriocin production via the XIP and CSP pheromones. CSP is effective in inducing bacteriocin responses but not competence in chemically defined media (CDM). This is in contrast to XIP, which is a strong inducer of competence in CDM but can also stimulate bacteriocin genes as a late response. Interconnections between the pathways activated by the two pheromones have been characterized in certain detail in S. mutans UA159, but it is mostly unknown whether such findings are representative for the species. In this study, we used bioassays based on luciferase reporters for the bacteriocin gene cipB and the alternative sigma factor sigX to investigate various S. mutans isolates for production and response to CSP and XIP pheromones in CDM. Similar to S. mutans UA159, endogenous CSP was undetectable in the culture supernatants of all tested strains. During optimization of the bioassay using the cipB reporter, we discovered that the activity of exogenous CSP used as a standard was reduced over time during S. mutans growth. Using a FRET-CSP reporter peptide, we found that S. mutans UA159 was able to degrade CSP, and that such activity was not significantly different in isogenic mutants with deletion of the protease gene htrA or the competence genes sigX, oppD, and comR. CSP cleavage was also detected in all the wild type strains, indicating that this is a conserved feature in S. mutans. For the XIP pheromone, endogenous production was observed in the supernatants of all 34 tested strains at peak concentrations in culture supernatants that varied between 200 and 26000 nM. Transformation in the presence of exogenous XIP was detected in all but one of the isolates. The efficiency of transformation varied, however, among the different strains, and for those with the highest transformation rates, endogenous XIP peak concentrations in the supernatants were above 2000 nM XIP. We conclude that XIP production and inducing effect on transformation, as well as the ability to degrade CSP, are conserved functions among different S. mutans isolates. Understanding the functionality and conservation of pheromone systems in S. mutans may lead to novel strategies to prevent or treat unbalances in oral microbiomes that may favor diseases.
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spelling pubmed-67539792019-09-30 Conserved Pheromone Production, Response and Degradation by Streptococcus mutans Ricomini Filho, Antonio Pedro Khan, Rabia Åmdal, Heidi Aarø Petersen, Fernanda C. Front Microbiol Microbiology Streptococcus mutans, a bacterium with high cariogenic potential, coordinates competence for natural transformation and bacteriocin production via the XIP and CSP pheromones. CSP is effective in inducing bacteriocin responses but not competence in chemically defined media (CDM). This is in contrast to XIP, which is a strong inducer of competence in CDM but can also stimulate bacteriocin genes as a late response. Interconnections between the pathways activated by the two pheromones have been characterized in certain detail in S. mutans UA159, but it is mostly unknown whether such findings are representative for the species. In this study, we used bioassays based on luciferase reporters for the bacteriocin gene cipB and the alternative sigma factor sigX to investigate various S. mutans isolates for production and response to CSP and XIP pheromones in CDM. Similar to S. mutans UA159, endogenous CSP was undetectable in the culture supernatants of all tested strains. During optimization of the bioassay using the cipB reporter, we discovered that the activity of exogenous CSP used as a standard was reduced over time during S. mutans growth. Using a FRET-CSP reporter peptide, we found that S. mutans UA159 was able to degrade CSP, and that such activity was not significantly different in isogenic mutants with deletion of the protease gene htrA or the competence genes sigX, oppD, and comR. CSP cleavage was also detected in all the wild type strains, indicating that this is a conserved feature in S. mutans. For the XIP pheromone, endogenous production was observed in the supernatants of all 34 tested strains at peak concentrations in culture supernatants that varied between 200 and 26000 nM. Transformation in the presence of exogenous XIP was detected in all but one of the isolates. The efficiency of transformation varied, however, among the different strains, and for those with the highest transformation rates, endogenous XIP peak concentrations in the supernatants were above 2000 nM XIP. We conclude that XIP production and inducing effect on transformation, as well as the ability to degrade CSP, are conserved functions among different S. mutans isolates. Understanding the functionality and conservation of pheromone systems in S. mutans may lead to novel strategies to prevent or treat unbalances in oral microbiomes that may favor diseases. Frontiers Media S.A. 2019-09-13 /pmc/articles/PMC6753979/ /pubmed/31572344 http://dx.doi.org/10.3389/fmicb.2019.02140 Text en Copyright © 2019 Ricomini Filho, Khan, Åmdal and Petersen. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Microbiology
Ricomini Filho, Antonio Pedro
Khan, Rabia
Åmdal, Heidi Aarø
Petersen, Fernanda C.
Conserved Pheromone Production, Response and Degradation by Streptococcus mutans
title Conserved Pheromone Production, Response and Degradation by Streptococcus mutans
title_full Conserved Pheromone Production, Response and Degradation by Streptococcus mutans
title_fullStr Conserved Pheromone Production, Response and Degradation by Streptococcus mutans
title_full_unstemmed Conserved Pheromone Production, Response and Degradation by Streptococcus mutans
title_short Conserved Pheromone Production, Response and Degradation by Streptococcus mutans
title_sort conserved pheromone production, response and degradation by streptococcus mutans
topic Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6753979/
https://www.ncbi.nlm.nih.gov/pubmed/31572344
http://dx.doi.org/10.3389/fmicb.2019.02140
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