Liu Li-Zhu, Nie Zhen-Yuan, Yang Yi, Pan Xuan, Xia Xu, Zhou Yu-Hang, Xia Jin-Lan, Zhang Li-Juan, Zhen Xiang-Jun, Yang Hong-Ying
School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China.
School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China; Key Lab of Biometallurgy of the Ministry of Education of China, Central South University, Changsha, 410083, China.
Res Microbiol. 2018 Dec;169(10):590-597. doi: 10.1016/j.resmic.2018.08.003. Epub 2018 Sep 1.
For the first time, synchrotron radiation (SR) -based carbon K-edge X-ray absorption near edge structure (XANES) spectroscopy in-situ characterization was conducted to evaluate the evolution of superficial (about 10 nm) organic components of extracellular polymeric substances (EPS) of thermoacidophilic archaeon Acidianus manzaensis YN-25 acclimated with different energy substrates (FeS, CuFeS, S, FeSO). The atomic force microscopy (AFM) morphology scanning showed that the strain acclimated with different energy substrates varied a lot in EPS amount. XANES results showed clear associations between the energy substrates and the changes in organic composition in terms of typical function groups (CO, CO and CN). The chalcopyrite- and pyrite-acclimated cells contained higher proportion of proteins but less proportion of polysaccharides than the S-acclimated cells. The FeSO-acclimated cells contained the highest proportion of proteins, while the S-acclimated cells contained more lipids and polysaccharides. The results of linear-combination and peak fitting of the K-edge XANES for the extracellular superficial organic component C is consistent with the trend in comparison with the results of FTIR and spectrophotometric determination, but there are significant differences in the values. These differences are caused by the inconsistencies of measurement depth between XANES and the latter two characterization methods.
首次采用基于同步辐射（SR）的碳K边X射线吸收近边结构（XANES）光谱原位表征技术，来评估嗜热嗜酸古菌曼扎阿西迪亚菌YN - 25在不同能量底物（FeS、CuFeS、S、FeSO）驯化下，其胞外聚合物（EPS）表面（约10纳米）有机成分的演变情况。原子力显微镜（AFM）形态扫描显示，在不同能量底物驯化下的菌株，其EPS含量差异很大。XANES结果表明，就典型官能团（CO、CO和CN）而言，能量底物与有机组成变化之间存在明显关联。与以S为底物驯化的细胞相比，以黄铜矿和黄铁矿为底物驯化的细胞含有更高比例的蛋白质，但多糖比例较低。以FeSO为底物驯化的细胞蛋白质比例最高，而以S为底物驯化的细胞含有更多的脂质和多糖。胞外表面有机成分C的K边XANES线性组合和峰拟合结果与傅里叶变换红外光谱（FTIR）和分光光度法测定结果相比趋势一致，但数值存在显著差异。这些差异是由XANES与后两种表征方法的测量深度不一致所致。
