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Yeast grown in continuous culture systems can detect mutagens with improved sensitivity relative to the Ames test

Continuous culture systems allow for the controlled growth of microorganisms over a long period of time. Here, we develop a novel test for mutagenicity that involves growing yeast in continuous culture systems exposed to low levels of mutagen for a period of approximately 20 days. In contrast, most...

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Autores principales: Ong, Joseph Y., Pence, Julia T., Molik, David C., Shepherd, Heather A. M., Goodson, Holly V.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7968628/
https://www.ncbi.nlm.nih.gov/pubmed/33730086
http://dx.doi.org/10.1371/journal.pone.0235303
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author Ong, Joseph Y.
Pence, Julia T.
Molik, David C.
Shepherd, Heather A. M.
Goodson, Holly V.
author_facet Ong, Joseph Y.
Pence, Julia T.
Molik, David C.
Shepherd, Heather A. M.
Goodson, Holly V.
author_sort Ong, Joseph Y.
collection PubMed
description Continuous culture systems allow for the controlled growth of microorganisms over a long period of time. Here, we develop a novel test for mutagenicity that involves growing yeast in continuous culture systems exposed to low levels of mutagen for a period of approximately 20 days. In contrast, most microorganism-based tests for mutagenicity expose the potential mutagen to the biological reporter at a high concentration of mutagen for a short period of time. Our test improves upon the sensitivity of the well-established Ames test by at least 20-fold for each of two mutagens that act by different mechanisms (the intercalator ethidium bromide and alkylating agent methyl methanesulfonate). To conduct the tests, cultures were grown in small, inexpensive continuous culture systems in media containing (potential) mutagen, and the resulting mutagenicity of the added compound was assessed via two methods: a canavanine-based plate assay and whole genome sequencing. In the canavanine-based plate assay, we were able to detect a clear relationship between the amount of mutagen and the number of canavanine-resistant mutant colonies over a period of one to three weeks of exposure. Whole genome sequencing of yeast grown in continuous culture systems exposed to methyl methanesulfonate demonstrated that quantification of mutations is possible by identifying the number of unique variants across each strain. However, this method had lower sensitivity than the plate-based assay and failed to distinguish the different concentrations of mutagen. In conclusion, we propose that yeast grown in continuous culture systems can provide an improved and more sensitive test for mutagenicity.
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spelling pubmed-79686282021-03-31 Yeast grown in continuous culture systems can detect mutagens with improved sensitivity relative to the Ames test Ong, Joseph Y. Pence, Julia T. Molik, David C. Shepherd, Heather A. M. Goodson, Holly V. PLoS One Research Article Continuous culture systems allow for the controlled growth of microorganisms over a long period of time. Here, we develop a novel test for mutagenicity that involves growing yeast in continuous culture systems exposed to low levels of mutagen for a period of approximately 20 days. In contrast, most microorganism-based tests for mutagenicity expose the potential mutagen to the biological reporter at a high concentration of mutagen for a short period of time. Our test improves upon the sensitivity of the well-established Ames test by at least 20-fold for each of two mutagens that act by different mechanisms (the intercalator ethidium bromide and alkylating agent methyl methanesulfonate). To conduct the tests, cultures were grown in small, inexpensive continuous culture systems in media containing (potential) mutagen, and the resulting mutagenicity of the added compound was assessed via two methods: a canavanine-based plate assay and whole genome sequencing. In the canavanine-based plate assay, we were able to detect a clear relationship between the amount of mutagen and the number of canavanine-resistant mutant colonies over a period of one to three weeks of exposure. Whole genome sequencing of yeast grown in continuous culture systems exposed to methyl methanesulfonate demonstrated that quantification of mutations is possible by identifying the number of unique variants across each strain. However, this method had lower sensitivity than the plate-based assay and failed to distinguish the different concentrations of mutagen. In conclusion, we propose that yeast grown in continuous culture systems can provide an improved and more sensitive test for mutagenicity. Public Library of Science 2021-03-17 /pmc/articles/PMC7968628/ /pubmed/33730086 http://dx.doi.org/10.1371/journal.pone.0235303 Text en © 2021 Ong et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://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
Ong, Joseph Y.
Pence, Julia T.
Molik, David C.
Shepherd, Heather A. M.
Goodson, Holly V.
Yeast grown in continuous culture systems can detect mutagens with improved sensitivity relative to the Ames test
title Yeast grown in continuous culture systems can detect mutagens with improved sensitivity relative to the Ames test
title_full Yeast grown in continuous culture systems can detect mutagens with improved sensitivity relative to the Ames test
title_fullStr Yeast grown in continuous culture systems can detect mutagens with improved sensitivity relative to the Ames test
title_full_unstemmed Yeast grown in continuous culture systems can detect mutagens with improved sensitivity relative to the Ames test
title_short Yeast grown in continuous culture systems can detect mutagens with improved sensitivity relative to the Ames test
title_sort yeast grown in continuous culture systems can detect mutagens with improved sensitivity relative to the ames test
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7968628/
https://www.ncbi.nlm.nih.gov/pubmed/33730086
http://dx.doi.org/10.1371/journal.pone.0235303
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