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Characterization of the roles of activated charcoal and Chelex in the induction of PrfA regulon expression in complex medium
The foodborne pathogen Listeria monocytogenes is able to survive across a wide range of intra- and extra-host environments by appropriately modulating gene expression patterns in response to different stimuli. Positive Regulatory Factor A (PrfA) is the major transcriptional regulator of virulence ge...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8084165/ https://www.ncbi.nlm.nih.gov/pubmed/33914817 http://dx.doi.org/10.1371/journal.pone.0250989 |
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author | Gaballa, Ahmed Sunil, Sriya Doll, Etienne Murphy, Sarah I. Bechtel, Tyler Guariglia-Oropeza, Veronica Wiedmann, Martin |
author_facet | Gaballa, Ahmed Sunil, Sriya Doll, Etienne Murphy, Sarah I. Bechtel, Tyler Guariglia-Oropeza, Veronica Wiedmann, Martin |
author_sort | Gaballa, Ahmed |
collection | PubMed |
description | The foodborne pathogen Listeria monocytogenes is able to survive across a wide range of intra- and extra-host environments by appropriately modulating gene expression patterns in response to different stimuli. Positive Regulatory Factor A (PrfA) is the major transcriptional regulator of virulence gene expression in L. monocytogenes. It has long been known that activated charcoal is required to induce the expression of PrfA-regulated genes in complex media, such as Brain Heart Infusion (BHI), but not in chemically defined media. In this study, we show that the expression of the PrfA-regulated hly, which encodes listeriolysin O, is induced 5- and 8-fold in L. monocytogenes cells grown in Chelex-treated BHI (Ch-BHI) and in the presence of activated charcoal (AC-BHI), respectively, relative to cells grown in BHI medium. Specifically, we show that metal ions present in BHI broth plays a role in the reduced expression of the PrfA regulon. In addition, we show that expression of hly is induced when the levels of bioavailable extra- or intercellular iron are reduced. L. monocytogenes cells grown Ch-BHI and AC-BHI media showed similar levels of resistance to the iron-activated antibiotic, streptonigrin, indicating that activated charcoal reduces the intracellular labile iron pool. Metal depletion and exogenously added glutathione contributed synergistically to PrfA-regulated gene expression since glutathione further increased hly expression in metal-depleted BHI but not in BHI medium. Analyses of transcriptional reporter fusion expression patterns revealed that genes in the PrfA regulon are differentially expressed in response to metal depletion, metal excess and exogenous glutathione. Our results suggest that metal ion abundance plays a role in modulating expression of PrfA-regulated virulence genes in L. monocytogenes. |
format | Online Article Text |
id | pubmed-8084165 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-80841652021-05-06 Characterization of the roles of activated charcoal and Chelex in the induction of PrfA regulon expression in complex medium Gaballa, Ahmed Sunil, Sriya Doll, Etienne Murphy, Sarah I. Bechtel, Tyler Guariglia-Oropeza, Veronica Wiedmann, Martin PLoS One Research Article The foodborne pathogen Listeria monocytogenes is able to survive across a wide range of intra- and extra-host environments by appropriately modulating gene expression patterns in response to different stimuli. Positive Regulatory Factor A (PrfA) is the major transcriptional regulator of virulence gene expression in L. monocytogenes. It has long been known that activated charcoal is required to induce the expression of PrfA-regulated genes in complex media, such as Brain Heart Infusion (BHI), but not in chemically defined media. In this study, we show that the expression of the PrfA-regulated hly, which encodes listeriolysin O, is induced 5- and 8-fold in L. monocytogenes cells grown in Chelex-treated BHI (Ch-BHI) and in the presence of activated charcoal (AC-BHI), respectively, relative to cells grown in BHI medium. Specifically, we show that metal ions present in BHI broth plays a role in the reduced expression of the PrfA regulon. In addition, we show that expression of hly is induced when the levels of bioavailable extra- or intercellular iron are reduced. L. monocytogenes cells grown Ch-BHI and AC-BHI media showed similar levels of resistance to the iron-activated antibiotic, streptonigrin, indicating that activated charcoal reduces the intracellular labile iron pool. Metal depletion and exogenously added glutathione contributed synergistically to PrfA-regulated gene expression since glutathione further increased hly expression in metal-depleted BHI but not in BHI medium. Analyses of transcriptional reporter fusion expression patterns revealed that genes in the PrfA regulon are differentially expressed in response to metal depletion, metal excess and exogenous glutathione. Our results suggest that metal ion abundance plays a role in modulating expression of PrfA-regulated virulence genes in L. monocytogenes. Public Library of Science 2021-04-29 /pmc/articles/PMC8084165/ /pubmed/33914817 http://dx.doi.org/10.1371/journal.pone.0250989 Text en © 2021 Gaballa et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Gaballa, Ahmed Sunil, Sriya Doll, Etienne Murphy, Sarah I. Bechtel, Tyler Guariglia-Oropeza, Veronica Wiedmann, Martin Characterization of the roles of activated charcoal and Chelex in the induction of PrfA regulon expression in complex medium |
title | Characterization of the roles of activated charcoal and Chelex in the induction of PrfA regulon expression in complex medium |
title_full | Characterization of the roles of activated charcoal and Chelex in the induction of PrfA regulon expression in complex medium |
title_fullStr | Characterization of the roles of activated charcoal and Chelex in the induction of PrfA regulon expression in complex medium |
title_full_unstemmed | Characterization of the roles of activated charcoal and Chelex in the induction of PrfA regulon expression in complex medium |
title_short | Characterization of the roles of activated charcoal and Chelex in the induction of PrfA regulon expression in complex medium |
title_sort | characterization of the roles of activated charcoal and chelex in the induction of prfa regulon expression in complex medium |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8084165/ https://www.ncbi.nlm.nih.gov/pubmed/33914817 http://dx.doi.org/10.1371/journal.pone.0250989 |
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