Ocean college of Hebei Agricultural University, Qinhuangdao, Hebei Province 066003, PR China; Hebei Key Laboratory of Nutrition Regulation and Disease Control for Aquaculture, Qinhuangdao, Hebei Province, 066003, PR China.
National Marine Hazard Mitigation Service, Ministry of Natural Resource of the People's Republic of China, Beijing, 100194, PR China.
Ecotoxicol Environ Saf. 2024 Sep 15;283:116851. doi: 10.1016/j.ecoenv.2024.116851. Epub 2024 Aug 10.
This study aimed to assess the ecological risks posed by sulfamethoxazole (SMX) at environmentally relevant concentrations. Specifically, its effects on the growth and biochemical components (total protein, total lipid, and total carbohydrate) of two marine microalgae species, namely Skeletonema costatum (S. costatum) and Phaeodactylum tricornutum (P. tricornutum), were investigated. Our findings revealed that concentrations of SMX below 150 ng/L stimulated the growth of both microalgae. Conversely, at higher concentrations, SMX inhibited their growth while promoting the synthesis of photosynthetic pigments, total protein, total lipid, and total carbohydrate (P < 0.05). Transmission electron microscope (TEM) observations demonstrated significant alterations in the ultrastructure of algal cells exposed to SMX, including nuclear marginalization, increased chloroplast volume, and heightened vacuolation. In addition, when SMX was lower than 250 ng/L, there was no oxidative damage in two microalgae cells. However, when SMX was higher than 250 ng/L, the antioxidant defense system of algal cells was activated to varying degrees, and the level of malondialdehyde (MDA) increased, indicating that algae cells were damaged by oxidation. From the molecular level, environmental concentration of SMX can induce microalgae cells to produce more energy substances, but there are almost no other adverse effects, indicating that the low level of SMX at the actual exposure level was unlikely to threaten P. tricornutum, but a higher concentration can significantly reduce its genetic products, which can affect the changes of its cell structure and damage P. tricornutum to some extent. Therefore, environmental concentration of SMX still has certain potential risks to microalgae. These outcomes improved current understanding of the potential ecological risks associated with SMX in marine environments.
本研究旨在评估环境相关浓度下磺胺甲恶唑（SMX）对海洋微藻的生态风险。具体而言，研究了磺胺甲恶唑对两种海洋微藻——骨条藻（Skeletonema costatum，S. costatum）和三角褐指藻（Phaeodactylum tricornutum，P. tricornutum）生长和生化成分（总蛋白、总脂和总碳水化合物）的影响。研究结果表明，SMX 浓度低于 150ng/L 时可促进两种微藻的生长。相反，在较高浓度时，SMX 抑制微藻生长，同时促进光合色素、总蛋白、总脂和总碳水化合物的合成（P<0.05）。透射电子显微镜（TEM）观察结果表明，暴露于 SMX 的藻细胞的超微结构发生了显著变化，包括核边缘化、叶绿体体积增加和空泡化加剧。此外，当 SMX 低于 250ng/L 时，两种微藻细胞均未发生氧化损伤。然而，当 SMX 高于 250ng/L 时，藻细胞的抗氧化防御系统被不同程度地激活，丙二醛（MDA）水平升高，表明藻细胞受到氧化损伤。从分子水平上看，环境浓度的 SMX 可以诱导微藻细胞产生更多的能量物质，但几乎没有其他不良影响，表明实际暴露水平下低浓度的 SMX 不太可能威胁到三角褐指藻，但较高浓度会显著降低其遗传产物，从而在一定程度上影响其细胞结构的变化并对三角褐指藻造成损害。因此，环境浓度的 SMX 对微藻仍具有一定的潜在风险。这些结果提高了我们对海洋环境中 SMX 潜在生态风险的认识。
