Chromium- and copper-induced inhibition of photosynthesis in Euglena gracilis analysed on the single-cell level by fluorescence kinetic microscopy
Here, we investigated effects of copper (Cu) and chromium (Cr) toxicity on two contrasting strains of Euglena gracilis, with and without chloroplasts, grown in culture media promoting either phototrophic or heterotrophic growth. This led to insights into Cr/Cu toxicity mechanisms and into the regula...
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todo:paper_0028646X_v182_n2_p405_Rocchetta2023-10-03T14:39:08Z Chromium- and copper-induced inhibition of photosynthesis in Euglena gracilis analysed on the single-cell level by fluorescence kinetic microscopy Rocchetta, I. Küpper, H. Chromium Copper Euglena Heavy metal toxicity Oxidative stress Photosynthesis Pigments Respiration carotenoid chlorophyll chromium copper hydrogen peroxide oxygen carotenoid cation chloroplast chromium comparative study copper ecotoxicology inhibition microscopy oxidation photochemistry photosynthesis pollution effect protist respiration toxicity test animal article cell respiration culture medium cytology drug effect Euglena gracilis fluorescence microscopy growth, development and aging metabolism oxidative stress photosynthesis physiology Animals Carotenoids Cell Respiration Chlorophyll Chromium Copper Culture Media Euglena gracilis Hydrogen Peroxide Microscopy, Fluorescence Oxidative Stress Oxygen Photosynthesis Euglena Euglena gracilis Here, we investigated effects of copper (Cu) and chromium (Cr) toxicity on two contrasting strains of Euglena gracilis, with and without chloroplasts, grown in culture media promoting either phototrophic or heterotrophic growth. This led to insights into Cr/Cu toxicity mechanisms and into the regulation of phototrophic vs heterotrophic metabolism. Our data strongly suggest that in Cu 2+ and Cr 6+ stressed Euglena photosynthesis is the primary target of damage. In the applied light conditions, this was mainly damage to the photosystem II reaction centre, as shown by single-cell measurements of photochemical fluorescence quenching. Respiration and photosynthetic dark reactions were less sensitive. The malfunctioning photosynthesis enhanced production of reactive oxygen species (mainly superoxide), leading to elevated amounts of carotenoid degradation products. At higher metal concentrations in chloroplast-containing cells, but not white cells, this oxidative stress resulted in increased respiratory oxygen uptake, likely by damage to mitochondria. During growth in nutrient solution promoting heterotrophic metabolism, the cells were able to repair the metal-induced damage to photosynthesis, moderating the inhibition of photochemistry. Growth in medium forcing the cells into photosynthesis increased the investment in photosynthetic pigments. Comparison of the two Euglena strains surprisingly showed that the previously metal-resistant strain lost this resistance during culture. © 2009 New Phytologist. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0028646X_v182_n2_p405_Rocchetta |
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Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Chromium Copper Euglena Heavy metal toxicity Oxidative stress Photosynthesis Pigments Respiration carotenoid chlorophyll chromium copper hydrogen peroxide oxygen carotenoid cation chloroplast chromium comparative study copper ecotoxicology inhibition microscopy oxidation photochemistry photosynthesis pollution effect protist respiration toxicity test animal article cell respiration culture medium cytology drug effect Euglena gracilis fluorescence microscopy growth, development and aging metabolism oxidative stress photosynthesis physiology Animals Carotenoids Cell Respiration Chlorophyll Chromium Copper Culture Media Euglena gracilis Hydrogen Peroxide Microscopy, Fluorescence Oxidative Stress Oxygen Photosynthesis Euglena Euglena gracilis |
| spellingShingle |
Chromium Copper Euglena Heavy metal toxicity Oxidative stress Photosynthesis Pigments Respiration carotenoid chlorophyll chromium copper hydrogen peroxide oxygen carotenoid cation chloroplast chromium comparative study copper ecotoxicology inhibition microscopy oxidation photochemistry photosynthesis pollution effect protist respiration toxicity test animal article cell respiration culture medium cytology drug effect Euglena gracilis fluorescence microscopy growth, development and aging metabolism oxidative stress photosynthesis physiology Animals Carotenoids Cell Respiration Chlorophyll Chromium Copper Culture Media Euglena gracilis Hydrogen Peroxide Microscopy, Fluorescence Oxidative Stress Oxygen Photosynthesis Euglena Euglena gracilis Rocchetta, I. Küpper, H. Chromium- and copper-induced inhibition of photosynthesis in Euglena gracilis analysed on the single-cell level by fluorescence kinetic microscopy |
| topic_facet |
Chromium Copper Euglena Heavy metal toxicity Oxidative stress Photosynthesis Pigments Respiration carotenoid chlorophyll chromium copper hydrogen peroxide oxygen carotenoid cation chloroplast chromium comparative study copper ecotoxicology inhibition microscopy oxidation photochemistry photosynthesis pollution effect protist respiration toxicity test animal article cell respiration culture medium cytology drug effect Euglena gracilis fluorescence microscopy growth, development and aging metabolism oxidative stress photosynthesis physiology Animals Carotenoids Cell Respiration Chlorophyll Chromium Copper Culture Media Euglena gracilis Hydrogen Peroxide Microscopy, Fluorescence Oxidative Stress Oxygen Photosynthesis Euglena Euglena gracilis |
| description |
Here, we investigated effects of copper (Cu) and chromium (Cr) toxicity on two contrasting strains of Euglena gracilis, with and without chloroplasts, grown in culture media promoting either phototrophic or heterotrophic growth. This led to insights into Cr/Cu toxicity mechanisms and into the regulation of phototrophic vs heterotrophic metabolism. Our data strongly suggest that in Cu 2+ and Cr 6+ stressed Euglena photosynthesis is the primary target of damage. In the applied light conditions, this was mainly damage to the photosystem II reaction centre, as shown by single-cell measurements of photochemical fluorescence quenching. Respiration and photosynthetic dark reactions were less sensitive. The malfunctioning photosynthesis enhanced production of reactive oxygen species (mainly superoxide), leading to elevated amounts of carotenoid degradation products. At higher metal concentrations in chloroplast-containing cells, but not white cells, this oxidative stress resulted in increased respiratory oxygen uptake, likely by damage to mitochondria. During growth in nutrient solution promoting heterotrophic metabolism, the cells were able to repair the metal-induced damage to photosynthesis, moderating the inhibition of photochemistry. Growth in medium forcing the cells into photosynthesis increased the investment in photosynthetic pigments. Comparison of the two Euglena strains surprisingly showed that the previously metal-resistant strain lost this resistance during culture. © 2009 New Phytologist. |
| format |
JOUR |
| author |
Rocchetta, I. Küpper, H. |
| author_facet |
Rocchetta, I. Küpper, H. |
| author_sort |
Rocchetta, I. |
| title |
Chromium- and copper-induced inhibition of photosynthesis in Euglena gracilis analysed on the single-cell level by fluorescence kinetic microscopy |
| title_short |
Chromium- and copper-induced inhibition of photosynthesis in Euglena gracilis analysed on the single-cell level by fluorescence kinetic microscopy |
| title_full |
Chromium- and copper-induced inhibition of photosynthesis in Euglena gracilis analysed on the single-cell level by fluorescence kinetic microscopy |
| title_fullStr |
Chromium- and copper-induced inhibition of photosynthesis in Euglena gracilis analysed on the single-cell level by fluorescence kinetic microscopy |
| title_full_unstemmed |
Chromium- and copper-induced inhibition of photosynthesis in Euglena gracilis analysed on the single-cell level by fluorescence kinetic microscopy |
| title_sort |
chromium- and copper-induced inhibition of photosynthesis in euglena gracilis analysed on the single-cell level by fluorescence kinetic microscopy |
| url |
http://hdl.handle.net/20.500.12110/paper_0028646X_v182_n2_p405_Rocchetta |
| work_keys_str_mv |
AT rocchettai chromiumandcopperinducedinhibitionofphotosynthesisineuglenagracilisanalysedonthesinglecelllevelbyfluorescencekineticmicroscopy AT kupperh chromiumandcopperinducedinhibitionofphotosynthesisineuglenagracilisanalysedonthesinglecelllevelbyfluorescencekineticmicroscopy |
| _version_ |
1782025304283283456 |