Department of Toxicology and Pharmacology, School of Veterinary Sciences, Complutense University, s/n Puerta de Hierro Ave., 28040 Madrid, Spain.
Chemosphere. 2010 Sep;81(2):282-7. doi: 10.1016/j.chemosphere.2010.05.051. Epub 2010 Jun 26.
Due to its various uses, chromium contamination has become widespread in a diverse array of environments. The present study was carried out to investigate the toxic effect of chromium exposures on sensitive and resistant strains of the green algae Dyctiosphaerium chlorelloides, and to determine the nature and mechanism of chromium-resistant cells that arise. The toxic effect on the photosynthetic performance of chromium exposures in both cell populations, and the sensitive differences due to chromium oxidation state, were estimated, and the results indicate that although the photosynthetic performance in both strains were inhibited, there are not significant differences among IC(50(72)) values obtained in toxicity assays with both chromium oxidation states in wild-type cells, and however these differences are very significant when the assays were performed with Cr(VI) resistant cells. The 72-h 50% inhibitory concentration values obtained with Cr(III) exposures were similar for both strains. Additionally, by means of the SEM/EDX and TEM microscopic techniques, the occurrence of rapid morphological evolution in the microalgal cells and the possible detoxificant mechanisms was observed after exposure of the wild strain to chromium hexavalent. Moreover, the different response in photosynthetic activity observed between sensitive and resistant cells of D. chlorelloides in the presence of Cr(VI) and Cr(III) could be used to obtain a chromium-specific eukaryotic microalgal biosensor.
由于其多种用途，铬污染已经在各种环境中广泛存在。本研究旨在研究铬暴露对绿藻双球藻敏感和抗性菌株的毒性作用，并确定产生抗铬细胞的性质和机制。评估了铬暴露对两种细胞群体光合作用性能的毒性作用，以及由于铬氧化态引起的敏感差异，结果表明，尽管两种菌株的光合作用性能均受到抑制，但在野生型细胞的毒性测定中，两种铬氧化态的 IC50(72) 值之间没有显著差异，然而，当用 Cr(VI)抗性细胞进行测定时，这些差异非常显著。用 Cr(III)暴露获得的 72 h 50%抑制浓度值对于两种菌株均相似。此外，通过 SEM/EDX 和 TEM 显微镜技术，在对六价铬进行暴露后，观察到野生菌株的微藻细胞迅速发生形态进化，以及可能的解毒机制。此外，在存在 Cr(VI)和 Cr(III)的情况下，D. chlorelloides 敏感和抗性细胞的光合作用活性观察到的不同反应可用于获得铬特异性真核微藻生物传感器。
