College of Environmental Science and Engineering, Dalian Maritime University, Dalian, China.
College of Environmental Science and Engineering, Dalian Maritime University, Dalian, China; Environmental Information Institute, Dalian Maritime University, Dalian, China.
Environ Pollut. 2021 Feb 15;271:116226. doi: 10.1016/j.envpol.2020.116226. Epub 2020 Dec 10.
It is highly likely that the toxicity of water accommodated fractions (WAF) will influence marine microalgae, and consequently lead to potential risk for the marine ecological environment. However, it was often neglected whether WAF can influence the transformation of relative compounds in organisms. The metabolism of amino acids (AAs) can be used to track physiological changes in microalgae because amino acids are the basis of proteins and enzymes. In this study, using marine Chlorophyta Platymonas helgolandica as the test organism, the effects of different concentrations of WAF on AA compositions and stable carbon isotope ratios (δC) of individual AAs of Platymonas helgolandica were investigated. The results showed that the WAF of #180 fuel oil had an obvious suppressing effect on the growth and chlorophyll a content of microalgae. The growth inhibitory rate at 96 h was 80.66% at a WAF concentration of 0.50 mg L compared with the control. Furthermore, seven among the 16 AAs, including alanine, cysteine, proline, aspartic acid, lysine, histidine and tyrosine, had relatively high abundance. Under the glycolysis pathway, the cysteine abundance was higher than control, meaning that the biosynthesized pathway of alanine through cysteine as a precursor could be damaged. Phosphoenolpyruvate (PEP) was an important synthesis precursor of alanine (leucine) and aromatic AA family (Phenylalanine and tyrosine), and played an important role in δC fractionation under the WAF stress. Under the TCA pathway, to protect cell metabolism activities under WAF stress, the δC value of threonine and proline abundance in microalgae with the increase in WAF stress. Therefore, δC fractionation can be used as a novel method for toxicity evaluation of WAF on future.
水可萃取部分（WAF）的毒性极有可能影响海洋微藻，进而对海洋生态环境产生潜在风险。然而，人们往往忽略了 WAF 是否会影响生物体内相关化合物的转化。氨基酸（AA）的代谢可以用来追踪微藻的生理变化，因为氨基酸是蛋白质和酶的基础。在这项研究中，以海洋绿藻原甲藻（Platymonas helgolandica）为受试生物，研究了不同浓度的 WAF 对原甲藻 AA 组成和个别 AA 的稳定碳同位素比值（δC）的影响。结果表明，180 号燃料油的 WAF 对微藻的生长和叶绿素 a 含量有明显的抑制作用。在 WAF 浓度为 0.50mg/L 时，96h 的生长抑制率为 80.66%，与对照组相比。此外，16 种 AA 中有 7 种（丙氨酸、半胱氨酸、脯氨酸、天冬氨酸、赖氨酸、组氨酸和酪氨酸）含量较高。在糖酵解途径中，半胱氨酸的丰度高于对照组，这意味着通过半胱氨酸作为前体合成丙氨酸的生物合成途径可能受到损害。磷酸烯醇丙酮酸（PEP）是丙氨酸（亮氨酸）和芳香族 AA 家族（苯丙氨酸和酪氨酸）的重要合成前体，在 WAF 胁迫下对 δC 分馏起着重要作用。在三羧酸（TCA）途径中，为了保护细胞在 WAF 胁迫下的代谢活动，微藻中苏氨酸和脯氨酸的 δC 值随 WAF 胁迫的增加而增加。因此，δC 分馏可以作为未来 WAF 毒性评价的一种新方法。
