Déniel Maureen, Lagarde Fabienne, Caruso Aurore, Errien Nicolas
Le Mans Université, IMMM UMR-CNRS 6283, Avenue Olivier Messiaen, 72085, Le Mans Cedex 9, France.
Laboratoire Mer, Molécules, Santé, EA 2160, Avenue Olivier Messiaen, 72085, Le Mans Cedex 9, France.
Anal Bioanal Chem. 2020 Jul;412(18):4413-4422. doi: 10.1007/s00216-020-02683-9. Epub 2020 May 8.
The unicellular photosynthetic organisms known as microalgae are becoming one of the most important models for aquatic system studies. Among them, Chlamydomonas reinhardtii is widely used as a bioindicator of pollution or of different changes in the environment. Numerous pollutants are present in aquatic environments, particularly plastics and nanoplastics. Physiological variations after an environmental change highlight variation in the macromolecular composition of microalgae (proteins, nucleic acids, lipids and carbohydrates). Recently, Fourier transform infrared vibrational spectroscopy has been described as a reliable tool, sensitive and allowing rapid measurement of macromolecular composition of microalgae. Coupled with preprocessing and principal component analysis, it is well adapted to monitoring the effect of environmental stress on biochemical composition. In this study, infrared spectroscopy, combined with multivariate analysis, has been tested first on known environmental stresses such as light intensity variation and nitrogen limitation. Then, this technique has been applied to monitor the interaction and potential impacts of polystyrene nanoparticles on microalgae. The results showed slight variations on protein and carbohydrates bands in the presence of nanoplastics, suggesting that their presence led to modifications in the biochemical composition of the microalgae. To confirm the interaction between microalgae and nanoplastics, visualization by confocal microscopy and cytotoxicity measurement has been carried out. Results showed that polystyrene nanoparticles seemed to adsorb on microalgae surface, leading to a loss of plasma membrane integrity. The resulting chemical modifications, even if moderate, could be detected by infrared spectroscopy' showing that this tool could be very helpful in the understanding of nanoparticle-microalgae interaction mechanisms.
被称为微藻的单细胞光合生物正成为水生系统研究中最重要的模型之一。其中，莱茵衣藻被广泛用作污染或环境中不同变化的生物指标。水生环境中存在大量污染物，尤其是塑料和纳米塑料。环境变化后的生理变化突出了微藻大分子组成（蛋白质、核酸、脂质和碳水化合物）的变化。最近，傅里叶变换红外振动光谱被描述为一种可靠的工具，灵敏且能够快速测量微藻的大分子组成。结合预处理和主成分分析，它非常适合监测环境胁迫对生化组成的影响。在本研究中，红外光谱结合多变量分析首先在已知的环境胁迫如光照强度变化和氮限制上进行了测试。然后，该技术被应用于监测聚苯乙烯纳米颗粒对微藻的相互作用和潜在影响。结果表明，在存在纳米塑料的情况下，蛋白质和碳水化合物条带略有变化，表明它们的存在导致了微藻生化组成的改变。为了证实微藻与纳米塑料之间的相互作用，进行了共聚焦显微镜可视化和细胞毒性测量。结果表明，聚苯乙烯纳米颗粒似乎吸附在微藻表面，导致质膜完整性丧失。由此产生的化学变化，即使程度适中，也可以通过红外光谱检测到，表明该工具在理解纳米颗粒 - 微藻相互作用机制方面可能非常有帮助。
