汉阳陵陶俑表面微生物群落结构与种群多样性分析

Structure and diversity of microbial community on the surface of pottery figurines in the Hanyang Mausoleum

摘要:

【背景】汉阳陵是我国截至目前发现的规模最大、陪葬级别最高的汉代陶俑群，出土了大量形神毕肖的裸体俑群，考古学家认为这种裸体陶俑原本“着衣、装木臂”，称为“着衣式陶俑”，为皇室独有，异常珍贵。然而这些推测尚无科学依据，而且陶俑表面附着微生物可能会腐蚀俑体。【目的】通过比较研究汉陶俑表面微生物的组成差异，为汉裸体陶俑着有衣物且装有断臂的推测提供一定的科学佐证，同时为汉陶俑微生物腐蚀的防控提供靶标。【方法】应用微生物高通量测序与纯培养相结合的方法，对着衣式陶俑不同部位微生物进行测定。【结果】高通量测序结果显示女俑头部微生物多样性较高；男俑上半身微生物多样性最高，腿部居中，头部较低。汉陶俑表面微生物组成按俑的类别及不同部位聚集在一起，其优势菌为放线菌门的克洛斯氏菌属、糖多孢菌属、假诺卡氏菌属及链霉菌科，其他各部位优势类群相对丰度存在差异，断臂处与碳循环相关功能微生物的相对丰度最高。纯培养结果显示女俑头部的可培养细菌数量高于男俑头部可培养的细菌数量；男俑上身与腿部可培养的微生物数量高于男俑头部，表明上半身与腿部可能有衣物覆盖，导致其营养差异。【结论】汉陶俑头部与身体表面部位微生物多样性与组成存在明显的差异，暗示汉陶俑各部位的营养成分存在差异，可能与汉陶俑有衣物覆盖或染料涂色相关。

Abstract:

[Background] Han Yangling Museum has been the largest group of pottery figurines of the Han Dynasty so far found in China. A large number of nude figurines have been unearthed. Archaeologists believe that these nude pottery figurines were originally dressed and equipped with wooden arms, which are unique to the royal family and extremely precious. However, there is no scientific support for these conjectures. In addition, the microorganisms attached to the surface may corrode the pottery figurines. [Objective] To provide scientific evidence for the speculation that clothes and broken arms exist by comparing the structure of microbial community on the surface of the pottery figurines, and to provide targets for the prevention and control of the microbial corrosion of pottery figurines in the Han Dynasty. [Methods] The microorganisms on different parts of the pottery figurines were identified by high-throughput sequencing and pure culture method. [Results] The high-throughput sequencing results showed that the microbial diversity in female figurines was higher on the head. In male figurines, the microbial diversity was high on the upper body, moderate on the legs, and low on the head. The microbial taxa on the surface of the pottery figurines were clustered according to the types and different parts of the figurines. The dominant groups were Clostridia, Saccharopolyspora, Pseudonocardia, and Streptomycetaceae of Actinomycetes. The relative abundance of dominant groups varied in different parts, and the relative abundance of the functional microorganisms involved in the carbon cycle on broken arms was the highest. The culturable bacteria on the head of female figurines were more than those on the head of male figurines. The culturable microorganisms on the upper body and legs were more than those on the head in male figurines. The upper body and legs may have been covered by clothing, which provided the habitats with different nutrients for microorganisms. [Conclusion] There were significant differences in microbial diversity and composition between the head and the body of the pottery figurines in the Han Dynasty, which suggested that the nutrient composition varied in different parts of the pottery figurines. Such differences might be related to the covering of the pottery figurines with clothes or dye.