Quantum chemical calculation studies toward microscopic understanding of retention mechanism of Cs radioisotopes and other alkali metals in lichens

Abstract We evaluate stability of cesium (Cs) and other alkali-metal cation complexes of lichen metabolites in both gas and aqueous phases to discuss why lichens can retain radioactive Cs in the thalli over several years. We focus on oxalic acid, (+)-usnic acid, atranorin, lecanoric acid, and protoc...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Hiroya Suno, Masahiko Machida, Terumi Dohi, Yoshihito Ohmura
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/90d63ab9ae4845a992b8ef35eb8063dc
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:90d63ab9ae4845a992b8ef35eb8063dc
record_format	dspace
spelling	oai:doaj.org-article:90d63ab9ae4845a992b8ef35eb8063dc2021-12-02T14:27:46ZQuantum chemical calculation studies toward microscopic understanding of retention mechanism of Cs radioisotopes and other alkali metals in lichens10.1038/s41598-021-87617-w2045-2322https://doaj.org/article/90d63ab9ae4845a992b8ef35eb8063dc2021-04-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-87617-whttps://doaj.org/toc/2045-2322Abstract We evaluate stability of cesium (Cs) and other alkali-metal cation complexes of lichen metabolites in both gas and aqueous phases to discuss why lichens can retain radioactive Cs in the thalli over several years. We focus on oxalic acid, (+)-usnic acid, atranorin, lecanoric acid, and protocetraric acid, which are common metabolite substances in various lichens including, e.g., Flavoparmelia caperata and Parmotrema tinctorum retaining Cs in Fukushima, Japan. By performing quantum chemical calculations, their gas-phase complexation energies and aqueous-solution complexation free energies with alkali-metal cations are computed for their neutral and deprotonated cases. Consequently, all the molecules are found to energetically favor cation complexations and the preference order is Li $$^+>$$ + > Na $$^+>$$ + > K $$^+>$$ + > Rb $$^+>$$ + > Cs $$^+$$ + for all conditions, indicating no specific Cs selectivity but strong binding with all alkali cations. Comparing complexation stabilities among these metabolites, lecanoric and protocetraric acids seen in medullary layer are found to keep higher affinity in their neutral case, while (+)-usnic acid and atranorin in upper cortex exhibit rather strong affinity only in deprotonated cases through forming stable six atoms’ ring containing alkali cation chelated by two oxygens. These results suggest that the medullary layer can catch all alkali cations in a wide pH range around the physiological one, while the upper cortex can effectively block penetration of metal ions when the metal stress grows. Such insights highlight a physiological role of metabolites like blocking of metal-cation migrations into intracellular tissues, and explain long-term retention of alkali cations including Cs in lichens containing enough such metabolites to bind them.Hiroya SunoMasahiko MachidaTerumi DohiYoshihito OhmuraNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-13 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Hiroya Suno Masahiko Machida Terumi Dohi Yoshihito Ohmura Quantum chemical calculation studies toward microscopic understanding of retention mechanism of Cs radioisotopes and other alkali metals in lichens
description	Abstract We evaluate stability of cesium (Cs) and other alkali-metal cation complexes of lichen metabolites in both gas and aqueous phases to discuss why lichens can retain radioactive Cs in the thalli over several years. We focus on oxalic acid, (+)-usnic acid, atranorin, lecanoric acid, and protocetraric acid, which are common metabolite substances in various lichens including, e.g., Flavoparmelia caperata and Parmotrema tinctorum retaining Cs in Fukushima, Japan. By performing quantum chemical calculations, their gas-phase complexation energies and aqueous-solution complexation free energies with alkali-metal cations are computed for their neutral and deprotonated cases. Consequently, all the molecules are found to energetically favor cation complexations and the preference order is Li $$^+>$$ + > Na $$^+>$$ + > K $$^+>$$ + > Rb $$^+>$$ + > Cs $$^+$$ + for all conditions, indicating no specific Cs selectivity but strong binding with all alkali cations. Comparing complexation stabilities among these metabolites, lecanoric and protocetraric acids seen in medullary layer are found to keep higher affinity in their neutral case, while (+)-usnic acid and atranorin in upper cortex exhibit rather strong affinity only in deprotonated cases through forming stable six atoms’ ring containing alkali cation chelated by two oxygens. These results suggest that the medullary layer can catch all alkali cations in a wide pH range around the physiological one, while the upper cortex can effectively block penetration of metal ions when the metal stress grows. Such insights highlight a physiological role of metabolites like blocking of metal-cation migrations into intracellular tissues, and explain long-term retention of alkali cations including Cs in lichens containing enough such metabolites to bind them.
format	article
author	Hiroya Suno Masahiko Machida Terumi Dohi Yoshihito Ohmura
author_facet	Hiroya Suno Masahiko Machida Terumi Dohi Yoshihito Ohmura
author_sort	Hiroya Suno
title	Quantum chemical calculation studies toward microscopic understanding of retention mechanism of Cs radioisotopes and other alkali metals in lichens
title_short	Quantum chemical calculation studies toward microscopic understanding of retention mechanism of Cs radioisotopes and other alkali metals in lichens
title_full	Quantum chemical calculation studies toward microscopic understanding of retention mechanism of Cs radioisotopes and other alkali metals in lichens
title_fullStr	Quantum chemical calculation studies toward microscopic understanding of retention mechanism of Cs radioisotopes and other alkali metals in lichens
title_full_unstemmed	Quantum chemical calculation studies toward microscopic understanding of retention mechanism of Cs radioisotopes and other alkali metals in lichens
title_sort	quantum chemical calculation studies toward microscopic understanding of retention mechanism of cs radioisotopes and other alkali metals in lichens
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/90d63ab9ae4845a992b8ef35eb8063dc
work_keys_str_mv	AT hiroyasuno quantumchemicalcalculationstudiestowardmicroscopicunderstandingofretentionmechanismofcsradioisotopesandotheralkalimetalsinlichens AT masahikomachida quantumchemicalcalculationstudiestowardmicroscopicunderstandingofretentionmechanismofcsradioisotopesandotheralkalimetalsinlichens AT terumidohi quantumchemicalcalculationstudiestowardmicroscopicunderstandingofretentionmechanismofcsradioisotopesandotheralkalimetalsinlichens AT yoshihitoohmura quantumchemicalcalculationstudiestowardmicroscopicunderstandingofretentionmechanismofcsradioisotopesandotheralkalimetalsinlichens
_version_	1718391266161459200

Quantum chemical calculation studies toward microscopic understanding of retention mechanism of Cs radioisotopes and other alkali metals in lichens

Ejemplares similares