Synchrotron Radiation-Fourier Transformed Infrared microspectroscopy (μSR-FTIR) reveals multiple metabolism alterations in microalgae induced by cadmium and mercury

[摘要] Toxic metals such as cadmium (Cd) and mercury (Hg) represent a threat to photosynthetic organisms of polluted aquatic ecosystems, and knowledge about mechanisms of toxicity is essential for appropriate assessment of environmental risks. We used Synchrotron Radiation-Fourier Transformed Infrared microspectroscopy (mu SRFTIR) to characterise major changes of biomolecules caused by Cd and Hg in the model green microalga Chlamydomonas reinhardtii. mu SR-FTIR showed several metabolic alterations in different biochemical groups such as carbohydrates, proteins, and lipids in a time-dose dependent manner, with the strongest changes occurring at concentrations above 10 mu M Cd and 15 mu M Hg after short-term (24 h) treatments. This occurred in a context where metals triggered intracellular oxidative stress and chloroplast damage, along with autophagy induction by overexpressing AUTOPHAGY-RELATED PROTEIN 8 (ATG8). Thin layer chromatography analysis confirmed that toxic metals promoted remarkable changes in lipid profile, with higher degree of esterified fatty acid unsaturation as detected by gas chromatography coupled with mass spectrometry. Under Cd stress, there was specifically higher unsaturation of free fatty acids, while Hg led to stronger unsaturation in monogalactosyldiacylglycerol. mu SR-FTIR spectroscopy proved as a valuable tool to identify biochemical alterations in microalgae, information that could be exploited to optimise approaches for metal decontamination.

[发布日期] 2021-10-05

[关键词] Biomolecular alterations;Chlamydomonas;Metal toxicity;Oxidative stress;Synchrotron radiation FTIR