Bioadsorption and bioaccumulation of chromium trivalent in Cr(III)-tolerant microalgae: A mechanisms for chromium resistance
| Autor: | S. Sánchez-Fortún, M.C. Bartolomé, Maria Pe Pereira |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Chromium
Environmental Engineering Health Toxicology and Mutagenesis chemistry.chemical_element Metal chemistry.chemical_compound Microalgae Environmental Chemistry Photosynthesis Hexavalent chromium biology Metallurgy Public Health Environmental and Occupational Health General Medicine General Chemistry biology.organism_classification Adaptation Physiological Pollution Biodegradation Environmental chemistry Vacuolization Bioaccumulation visual_art Ultrastructure visual_art.visual_art_medium Green algae Water Pollutants Chemical Nuclear chemistry Cell wall thickening |
| Zdroj: | Chemosphere. 93:1057-1063 |
| ISSN: | 0045-6535 |
| DOI: | 10.1016/j.chemosphere.2013.05.078 |
| Popis: | Anthropogenic activity constantly releases heavy metals into the environment. The heavy metal chromium has a wide industrial use and exists in two stable oxidation states: trivalent and hexavalent. While hexavalent chromium uptake in plant cells has been reported that an active process by carrying essential anions, the cation Cr(III) appears to be taken up inactively. Dictyosphaerium chlorelloides (Dc1M), an unicellular green alga is a well-studied cell biological model organism. The present study was carried out to investigate the toxic effect of chromium exposures on wild-type Cr(III)-sensitive (Dc1M(wt)) and Cr(III)-tolerant (Dc1M(Cr(III)R30)) strains of these green algae, and to determine the potential mechanism of chromium resistance. Using cell growth as endpoint to determine Cr(III)-sensitivity, the IC₅₀(₇₂) values obtained show significant differences of sensitivity between wild type and Cr(III)-tolerant cells. Scanning electron microscopy (SEM) showed significant morphological differences between both strains, such as decrease in cell size or reducing the coefficient of form; and transmission electron microscopy (TEM) revealed ultrastructural changes such as increased vacuolization and cell wall thickening in the Cr(III)-tolerant strain with respect to the wild-type strain. Energy dispersive X-ray analysis (SEM/XEDS) revealed that Cr(III)-tolerant D. chlorelloides cells are able to accumulate considerable amounts of chromium distributed in cell wall (bioadsorption) as well as in cytoplasm, vacuoles, and chloroplast (bio-accumulation). Morphological changes of Cr(III)-tolerant D. chlorelloides cells and the presence of these electron-dense bodies in their cell structures can be understood as a Cr(III) detoxification mechanism. |
| Databáze: | OpenAIRE |
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