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Can Parietin Transfer Energy Radiatively to Photosynthetic Pigments?

The main role of lichen anthraquinones is in protection against biotic and abiotic stresses, such as UV radiation. These compounds are frequently deposited as crystals outside the fungal hyphae and most of them emit visible fluorescence when excited by UV. We wondered whether the conversion of UV in...

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Autores principales: Fernández-Marín, Beatriz, Artetxe, Unai, Becerril, José María, Martínez-Abaigar, Javier, Núñez-Olivera, Encarnación, García-Plazaola, José Ignacio
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6099737/
https://www.ncbi.nlm.nih.gov/pubmed/30018202
http://dx.doi.org/10.3390/molecules23071741
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author Fernández-Marín, Beatriz
Artetxe, Unai
Becerril, José María
Martínez-Abaigar, Javier
Núñez-Olivera, Encarnación
García-Plazaola, José Ignacio
author_facet Fernández-Marín, Beatriz
Artetxe, Unai
Becerril, José María
Martínez-Abaigar, Javier
Núñez-Olivera, Encarnación
García-Plazaola, José Ignacio
author_sort Fernández-Marín, Beatriz
collection PubMed
description The main role of lichen anthraquinones is in protection against biotic and abiotic stresses, such as UV radiation. These compounds are frequently deposited as crystals outside the fungal hyphae and most of them emit visible fluorescence when excited by UV. We wondered whether the conversion of UV into visible fluorescence might be photosynthetically used by the photobiont, thereby converting UV into useful energy. To address this question, thalli of Xanthoria parietina were used as a model system. In this species the anthraquinone parietin accumulates in the outer upper cortex, conferring the species its characteristic yellow-orange colouration. In ethanol, parietin absorbed strongly in the blue and UV-B and emitted fluorescence in the range 480–540 nm, which partially matches with the absorption spectra of photosynthetic pigments. In intact thalli, it was determined by confocal microscopy that fluorescence emission spectra shifted 90 nm towards longer wavelengths. Then, to study energy transfer from parietin, we compared the response to UV of untreated and parietin-free thalli (removed with acetone). A chlorophyll fluorescence kinetic assessment provided evidence of UV-induced electron transport, though independently of the presence of parietin. Thus, a role for anthraquinones in energy harvesting is not supported for X. parietina under presented experimental conditions.
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spelling pubmed-60997372018-11-13 Can Parietin Transfer Energy Radiatively to Photosynthetic Pigments? Fernández-Marín, Beatriz Artetxe, Unai Becerril, José María Martínez-Abaigar, Javier Núñez-Olivera, Encarnación García-Plazaola, José Ignacio Molecules Communication The main role of lichen anthraquinones is in protection against biotic and abiotic stresses, such as UV radiation. These compounds are frequently deposited as crystals outside the fungal hyphae and most of them emit visible fluorescence when excited by UV. We wondered whether the conversion of UV into visible fluorescence might be photosynthetically used by the photobiont, thereby converting UV into useful energy. To address this question, thalli of Xanthoria parietina were used as a model system. In this species the anthraquinone parietin accumulates in the outer upper cortex, conferring the species its characteristic yellow-orange colouration. In ethanol, parietin absorbed strongly in the blue and UV-B and emitted fluorescence in the range 480–540 nm, which partially matches with the absorption spectra of photosynthetic pigments. In intact thalli, it was determined by confocal microscopy that fluorescence emission spectra shifted 90 nm towards longer wavelengths. Then, to study energy transfer from parietin, we compared the response to UV of untreated and parietin-free thalli (removed with acetone). A chlorophyll fluorescence kinetic assessment provided evidence of UV-induced electron transport, though independently of the presence of parietin. Thus, a role for anthraquinones in energy harvesting is not supported for X. parietina under presented experimental conditions. MDPI 2018-07-17 /pmc/articles/PMC6099737/ /pubmed/30018202 http://dx.doi.org/10.3390/molecules23071741 Text en © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Communication
Fernández-Marín, Beatriz
Artetxe, Unai
Becerril, José María
Martínez-Abaigar, Javier
Núñez-Olivera, Encarnación
García-Plazaola, José Ignacio
Can Parietin Transfer Energy Radiatively to Photosynthetic Pigments?
title Can Parietin Transfer Energy Radiatively to Photosynthetic Pigments?
title_full Can Parietin Transfer Energy Radiatively to Photosynthetic Pigments?
title_fullStr Can Parietin Transfer Energy Radiatively to Photosynthetic Pigments?
title_full_unstemmed Can Parietin Transfer Energy Radiatively to Photosynthetic Pigments?
title_short Can Parietin Transfer Energy Radiatively to Photosynthetic Pigments?
title_sort can parietin transfer energy radiatively to photosynthetic pigments?
topic Communication
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6099737/
https://www.ncbi.nlm.nih.gov/pubmed/30018202
http://dx.doi.org/10.3390/molecules23071741
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