Biomineralization of strontium and barium contributes to detoxification in the freshwater alga Micrasterias
Copyright © 2018 The Authors. Published by Elsevier GmbH.. All rights reserved.
| Veröffentlicht in: | Journal of plant physiology. - 1979. - 230(2018) vom: 01. Nov., Seite 80-91 |
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| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2018
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| Zugriff auf das übergeordnete Werk: | Journal of plant physiology |
| Schlagworte: | Journal Article Barium Electron energy loss spectroscopy Micrasterias denticulata Raman microscopy Strontium TEM Barium Compounds Chlorides Reactive Oxygen Species mehr... |
| Zusammenfassung: | Copyright © 2018 The Authors. Published by Elsevier GmbH.. All rights reserved. The unicellular model alga Micrasterias denticulata inhabits acid peat bogs that are highly endangered by pollutants due to their high humidity. As it was known from earlier studies that algae like Micrasterias are capable of storing barium naturally in form of BaSO4 crystals, it was interesting to experimentally investigate distribution and sequestration of barium and the chemically similar alkaline earth metal strontium. Additionally, we intended to analyze whether biomineralization by crystal formation contributes to diminution of the generally toxic effects of these minerals to physiology and structure of this alga which is closely related to higher plants. The results show that depending on the treatment differently shaped crystals are formed in BaCl2 and Cl2Sr exposed Micrasterias cells. Modern microscopic techniques such as analytical TEM by electron energy loss spectroscopy and Raman microscopy provide evidence for the chemical composition of these crystals. It is shown that barium treatment results in the formation of insoluble BaSO4 crystals that develop within distinct compartments. During strontium exposure long rod-like crystals are formed and are surrounded by membranes. Based on the Raman signature of these crystals their composition is attributed to strontium citrate. These crystals are instable and are dissolved during cell death. During strontium as well as barium treatment cell division rates and photosynthetic oxygen production decreased in dependence of the concentration, whereas cell vitality was reduced only slightly. Together with the fact that TEM analyses revealed only minor ultrastructural alterations as consequence of relatively high concentrated BaCl2 and Cl2Sr exposure, this indicates that biomineralization of Sr and Ba protects the cells from severe damage or cell death at least within a particular concentration range and time period. In the case of Sr treatment where ROS levels were found to be elevated, hallmarks for autophagy of single organelles were observed by TEM, indicating beginning degradation processes |
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| Beschreibung: | Date Completed 09.01.2019 Date Revised 29.01.2022 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1618-1328 |
| DOI: | 10.1016/j.jplph.2018.08.008 |