Mechanisms of lead-containing pigment discoloration caused by Naumannella cuiyingiana AFT2T isolated from 1500 years tomb wall painting of China
Mechanisms of lead-containing pigment discoloration caused by Naumannella cuiyingiana AFT2T isolated from 1500 years tomb wall painting of China
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DOI：
10.1016/j.ibiod.2023.105689
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发表时间：
2023-10-09
影响因子：
4.8
通讯作者：
Feng，Huyuan
中科院分区：
文献类型：
--
作者：
Pei，Shuwei;Wu，Fasi;Feng，Huyuan
古代壁画的生物退化是一种普遍存在的现象，威胁着宝贵文化遗产的长期生存。在这项研究中，从 1500 年前的墓画表面分离出的 Naumannella cuiyingiana AFT2T 被发现能够改变含铅颜料的外观颜色。通过对 Pb 改良处理下菌株 AFT2T 的生理生化测量和转录组分析相结合，进一步深入研究了其变色机制。孵化实验表明变色反应是含铅颜料与菌株AFT2T细胞相互作用的结果。随后，我们通过 EDX 图谱发现菌株 AFT2T 具有从颜料中吸收 Pb 离子的能力。最后，与对照进行比较后，推测观察到的变色是细胞产物 PbS 的形成，并进行了一系列额外的测试来验证这一点。此外，通过控制培养基中的化学成分来确定S的来源，这可能与培养基中动物蛋白的含硫氨基酸有关。转录组分析表明，Pb胁迫强烈影响菌株AFT2T中一些基因的表达，例如金属离子转运和代谢基因以及与TlpA家族蛋白二硫键还原酶相关的基因。其中，具有二硫键还原特性的酶基因和编码二价铅离子摄取转运蛋白的基因是变色过程中的关键基因。结合生化反应和转录组分析，揭示了 AFT2T 菌株导致含铅色素变色的关键基因。这些成果不仅为文物保护提供了新的见解和理论依据，也为环境重金属污染治理提供了新的手段。
Biodeterioration of ancient wall paintings is a ubiquitous phenomenon that threatens the long-term survival of invaluable cultural heritage. In this study, theNaumannella cuiyingianaAFT2T, isolated from the surface of tomb paintings dating back 1500 years, was observed to be capable of altering the appearing colors of Pb-containing pigments. By a combination of physiological and biochemical measurements and transcriptomic analysis of strain AFT2Tunder Pb amendment treatments, the discoloration mechanisms were investigated further in depth. Incubation experiments showed that the discoloration reaction resulted from an interaction between Pb-containing pigments and strain AFT2Tcells. Subsequently, we found that strain AFT2Thad ability to assimilate Pb ions from pigments by using EDX mapping. Finally, after comparing to the controls, it is speculated that the observed discoloration is the formation of cellular product PbS and a series of additional tests were conducted to verify this. In addition, controlling the chemical composition in the culture medium was utilized to confirm the source of S which might be related to the sulfur-containing amino acids of animal proteins in the medium. Transcriptomic analysis exhibited that Pb stress strongly affected the expression of some genes in strain AFT2T, such as metal ion transport and metabolism genes and genes related to the TlpA family protein disulfide reductases. Among them, the gene of the enzyme with disulfide-bond reducing properties and the gene encoding the divalent Pb ion uptake transporter are the key genes in the process of discoloration. A combination of biochemical reactions and transcriptomic analysis was utilized to reveal the key genes involved in the discoloration of Pb-containing pigments by strain AFT2T. These results provide not only new insights and a theoretical basis for the conservation of cultural relics but also a new means for the management of heavy metal pollution in the environments.