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Nitrogen and phosphorus significantly alter growth, nitrogen fixation, anatoxin-a content, and the transcriptome of the bloom-forming cyanobacterium, Dolichospermum

While freshwater cyanobacteria are traditionally thought to be limited by the availability of phosphorus (P), fixed nitrogen (N) supply can promote the growth and/or toxin production of some genera. This study characterizes how growth on N(2) (control), nitrate (NO(3)(–)), ammonium (NH(4)(+)), and u...

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Autores principales: Kramer, Benjamin J., Jankowiak, Jennifer G., Nanjappa, Deepak, Harke, Matthew J., Gobler, Christopher J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9490380/
https://www.ncbi.nlm.nih.gov/pubmed/36160233
http://dx.doi.org/10.3389/fmicb.2022.955032
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author Kramer, Benjamin J.
Jankowiak, Jennifer G.
Nanjappa, Deepak
Harke, Matthew J.
Gobler, Christopher J.
author_facet Kramer, Benjamin J.
Jankowiak, Jennifer G.
Nanjappa, Deepak
Harke, Matthew J.
Gobler, Christopher J.
author_sort Kramer, Benjamin J.
collection PubMed
description While freshwater cyanobacteria are traditionally thought to be limited by the availability of phosphorus (P), fixed nitrogen (N) supply can promote the growth and/or toxin production of some genera. This study characterizes how growth on N(2) (control), nitrate (NO(3)(–)), ammonium (NH(4)(+)), and urea as well as P limitation altered the growth, toxin production, N(2) fixation, and gene expression of an anatoxin-a (ATX-A) – producing strain of Dolichospermum sp. 54. The transcriptomes of fixed N and P-limited cultures differed significantly from those of fixed N-deplete, P-replete (control) cultures, while the transcriptomes of P-replete cultures amended with either NH(4)(+) or NO(3)(–) were not significantly different relative to those of the control. Growth rates of Dolichospermum (sp. 54) were significantly higher when grown on fixed N relative to without fixed N; growth on NH(4)(+) was also significantly greater than growth on NO(3)(–). NH(4)(+) and urea significantly lowered N(2) fixation and nifD gene transcript abundance relative to the control while cultures amended with NO(3)(–) exhibited N(2) fixation and nifD gene transcript abundance that was not different from the control. Cultures grown on NH(4)(+) exhibited the lowest ATX-A content per cell and lower transcript abundance of genes associated ATX-A synthesis (ana), while the abundance of transcripts of several ana genes were highest under fixed N and P - limited conditions. The significant negative correlation between growth rate and cellular anatoxin quota as well as the significantly higher number of transcripts of ana genes in cultures deprived of fixed N and P relative to P-replete cultures amended with NH(4)(+) suggests ATX-A was being actively synthesized under P limitation. Collectively, these findings indicate that management strategies that do not regulate fixed N loading will leave eutrophic water bodies vulnerable to more intense and toxic (due to increased biomass) blooms of Dolichospermum.
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spelling pubmed-94903802022-09-22 Nitrogen and phosphorus significantly alter growth, nitrogen fixation, anatoxin-a content, and the transcriptome of the bloom-forming cyanobacterium, Dolichospermum Kramer, Benjamin J. Jankowiak, Jennifer G. Nanjappa, Deepak Harke, Matthew J. Gobler, Christopher J. Front Microbiol Microbiology While freshwater cyanobacteria are traditionally thought to be limited by the availability of phosphorus (P), fixed nitrogen (N) supply can promote the growth and/or toxin production of some genera. This study characterizes how growth on N(2) (control), nitrate (NO(3)(–)), ammonium (NH(4)(+)), and urea as well as P limitation altered the growth, toxin production, N(2) fixation, and gene expression of an anatoxin-a (ATX-A) – producing strain of Dolichospermum sp. 54. The transcriptomes of fixed N and P-limited cultures differed significantly from those of fixed N-deplete, P-replete (control) cultures, while the transcriptomes of P-replete cultures amended with either NH(4)(+) or NO(3)(–) were not significantly different relative to those of the control. Growth rates of Dolichospermum (sp. 54) were significantly higher when grown on fixed N relative to without fixed N; growth on NH(4)(+) was also significantly greater than growth on NO(3)(–). NH(4)(+) and urea significantly lowered N(2) fixation and nifD gene transcript abundance relative to the control while cultures amended with NO(3)(–) exhibited N(2) fixation and nifD gene transcript abundance that was not different from the control. Cultures grown on NH(4)(+) exhibited the lowest ATX-A content per cell and lower transcript abundance of genes associated ATX-A synthesis (ana), while the abundance of transcripts of several ana genes were highest under fixed N and P - limited conditions. The significant negative correlation between growth rate and cellular anatoxin quota as well as the significantly higher number of transcripts of ana genes in cultures deprived of fixed N and P relative to P-replete cultures amended with NH(4)(+) suggests ATX-A was being actively synthesized under P limitation. Collectively, these findings indicate that management strategies that do not regulate fixed N loading will leave eutrophic water bodies vulnerable to more intense and toxic (due to increased biomass) blooms of Dolichospermum. Frontiers Media S.A. 2022-09-07 /pmc/articles/PMC9490380/ /pubmed/36160233 http://dx.doi.org/10.3389/fmicb.2022.955032 Text en Copyright © 2022 Kramer, Jankowiak, Nanjappa, Harke and Gobler. https://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
Kramer, Benjamin J.
Jankowiak, Jennifer G.
Nanjappa, Deepak
Harke, Matthew J.
Gobler, Christopher J.
Nitrogen and phosphorus significantly alter growth, nitrogen fixation, anatoxin-a content, and the transcriptome of the bloom-forming cyanobacterium, Dolichospermum
title Nitrogen and phosphorus significantly alter growth, nitrogen fixation, anatoxin-a content, and the transcriptome of the bloom-forming cyanobacterium, Dolichospermum
title_full Nitrogen and phosphorus significantly alter growth, nitrogen fixation, anatoxin-a content, and the transcriptome of the bloom-forming cyanobacterium, Dolichospermum
title_fullStr Nitrogen and phosphorus significantly alter growth, nitrogen fixation, anatoxin-a content, and the transcriptome of the bloom-forming cyanobacterium, Dolichospermum
title_full_unstemmed Nitrogen and phosphorus significantly alter growth, nitrogen fixation, anatoxin-a content, and the transcriptome of the bloom-forming cyanobacterium, Dolichospermum
title_short Nitrogen and phosphorus significantly alter growth, nitrogen fixation, anatoxin-a content, and the transcriptome of the bloom-forming cyanobacterium, Dolichospermum
title_sort nitrogen and phosphorus significantly alter growth, nitrogen fixation, anatoxin-a content, and the transcriptome of the bloom-forming cyanobacterium, dolichospermum
topic Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9490380/
https://www.ncbi.nlm.nih.gov/pubmed/36160233
http://dx.doi.org/10.3389/fmicb.2022.955032
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