Accelerated productions and physicochemical characterizations of different extracellular polymeric substances from Chiorella vulgaris with nano-ZnO
Accelerated productions and physicochemical characterizations of different extracellular polymeric substances from Chiorella vulgaris with nano-ZnO
复制标题
用纳米 ZnO 加速 Chiorella vulgaris 不同胞外聚合物的生产和理化表征
DOI：
10.1016/j.scitotenv.2018.12.019
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发表时间：
2019
影响因子：
9.8
通讯作者：
Ge Fei
中科院分区：
文献类型：
--
作者：
Zhao Jinfeng;Liu Shixiang;Liu Na;Zhang Han;Zhou Qiongzhi;Ge Fei
胞外聚合物（Extracellular polymeric substances，EPS）在保护细胞免受环境胁迫方面起着重要作用。然而，很少有人知道不同的EPS在这些过程中的作用。研究了纳米氧化锌（nano-ZnO）胁迫下小球藻（Chlorella vulgaris）胞外多糖（EPS）的两种不同组分--可溶性EPS（S-EPS）和结合型EPS（B-EPS）的产生及其理化性质。在72 h的培养过程中，添加0.01和0.04 mM的纳米ZnO后，S-EPS和B-EPS（可溶性有机碳、多糖和蛋白质）的含量均有所增加。无EPS-Free（EPS-F）细胞比添加纳米ZnO的EPS-Cover（EPS-C）细胞产生更多的S-EPS和B-EPS，尤其是添加0.04 mM纳米ZnO的EPS-F细胞S-EPS中蛋白质含量在72 h时比对照增加了45.5%。纳米ZnO对S-EPS中蛋白质的类色氨酸物质的化学静态猝灭作用强于对类酪氨酸物质的猝灭作用。此外，还证实了蛋白质中的羟基（单键OH）、羧基（C单键O）、酰胺I的C双键O、酰胺II的N单键H/C单键N参与了S-EPS和B-EPS与纳米ZnO的反应，同时蛋白质中的半缩醛基团被氧化为羧基。本研究可以为进一步了解EPS在纳米颗粒保护细胞免受损伤方面的作用提供参考。
Extracellular polymeric substances (EPS) play significant roles in protecting cells against environmental stresses. However, little information is known about the roles of different EPS in these processes. In this study, the productions and physicochemical characterizations of soluble-EPS (S-EPS) and bound-EPS (B-EPS), the two different fractions of EPS from a green algaChlorella vulgarisunder the stress of ZnO nanoparticle (nano-ZnO) were investigated. The contents of S-EPS and B-EPS which described as dissolved organic carbon, polysaccharides and proteins, both increased with the addition of tested nano-ZnO (0.01 and 0.04 mM) in a 72 h cultivation. EPS-Free (EPS-F) cells produced more S-EPS and B-EPS than the EPS-Cover (EPS-C) cells did with the tested nano-ZnO, especially the contents of protein in the S-EPS of EPS-F cells increased by 45.5% with 0.04 mM nano-ZnO compared to the control at 72 h. Tryptophan-like substances of the protein in S-EPS exhibited a stronger chemical static quenching than tyrosine-like substances with nano-ZnO. In addition, the hydroxyl (single bondOH) as well as carboxyl (Csingle bondO) group, and Cdouble bondO of amide I, Nsingle bondH/Csingle bondN of amide II groups in proteins were confirmed that involved in the reaction of S-EPS and B-EPS with nano-ZnO, meanwhile hemiacetal groups in saccharides were oxidized to carboxyl groups. This study could provide a better understanding of EPS in protecting against cells damage with nanoparticles.