Laboratory of Cultural Relics Conservation Materials, Department of Chemistry, Zhejiang University, Hangzhou, China.
Department of Cultural Heritage and Museology, Zhejiang University, Hangzhou, China.
Appl Environ Microbiol. 2018 Mar 19;84(7). doi: 10.1128/AEM.02680-17. Print 2018 Apr 1.
Research on the microbial communities that colonize stone monuments may provide a new understanding of stone biodeterioration and microbe-induced carbonate precipitation. This work investigated the seasonal variation of microbial communities in 2016 and 2017, as well as its effects on stone monuments. We determined the bacterial and fungal compositions of 12 samples from four well-separated geographic locations by using 16S rRNA and internal transcribed spacer gene amplicon sequencing. and Ascomycota were the predominant bacterial and fungal phyla, respectively, and differences in species abundance among our 12 samples and 2 years showed no consistent temporal or spatial trends. Alpha diversity, estimated by Shannon and Simpson indices, revealed that an increase or decrease in bacterial diversity corresponded to a decrease or increase in the fungal community from 2016 to 2017. Large-scale association analysis identified potential bacteria and fungi correlated with stone deterioration. Functional prediction revealed specific pathways and microbiota associated with stone deterioration. Moreover, a culture-dependent technique was used to identify microbial isolates involved in biodeterioration and carbonatogenesis; 64% of 85 bacterial isolates caused precipitation of carbonates in biomineralization assays. Imaging techniques including scanning electron microscopy with energy-dispersive spectroscopy, X-ray diffraction, and fluorescence imaging identified CaCO crystals as calcite and vaterite. Although CaCO precipitation induced by bacteria often has esthetically deleterious impacts on stone monuments, this process may potentially serve as a novel, environmentally friendly bacterial self-inoculation approach to the conservation of stone. Comprehensive analyses of the microbiomes associated with the deterioration of stone monuments may contribute to the understanding of mechanisms of deterioration, as well as to the identification of potentially beneficial or undesirable microbial communities and their genomic pathways. In our study, we demonstrated that was the predominant bacterial phylum and exhibited an increase from 2016 to 2017, while showed a decreasing trend. Apart from esthetic deterioration caused by cyanobacteria and fungi, white plaque, which is composed mainly of CaCO and is probably induced by and , was also considered to be another threat to stone monuments. We showed that there was no significant correlation between microbial population variation and geographic location. Specific functional genes and pathways were also enriched in particular bacterial species. The CaCO precipitation induced by an indigenous community of carbonatogenic bacteria also provides a self-inoculation approach for the conservation of stone.
对定植于石质文物表面的微生物群落的研究可能为了解石质文物的生物劣化和微生物诱导的碳酸盐沉淀提供新的认识。本研究于 2016 年和 2017 年调查了微生物群落的季节性变化及其对石质文物的影响。我们通过 16S rRNA 和内部转录间隔区基因扩增子测序，从四个地理位置相隔较远的地点的 12 个样本中确定了细菌和真菌的组成。变形菌门和子囊菌门分别是主要的细菌和真菌门，我们 12 个样本和 2 年的物种丰度差异没有表现出一致的时间或空间趋势。通过 Shannon 和 Simpson 指数估计的 alpha 多样性表明，从 2016 年到 2017 年，细菌多样性的增加或减少对应于真菌群落的减少或增加。大规模关联分析确定了与石质文物劣化相关的潜在细菌和真菌。功能预测揭示了与石质文物劣化相关的特定途径和微生物群。此外，我们还使用依赖培养的技术来鉴定参与生物劣化和碳酸盐生成的微生物分离物；在生物矿化实验中，85 个细菌分离物中有 64%导致碳酸盐沉淀。包括扫描电子显微镜与能量色散光谱、X 射线衍射和荧光成像在内的成像技术鉴定出 CaCO3 晶体为方解石和文石。尽管细菌诱导的 CaCO3 沉淀常常对石质文物的美观产生有害影响，但该过程可能潜在地作为一种新颖的、环保的细菌自我接种方法，用于石质文物的保护。对与石质文物劣化相关的微生物组的综合分析可能有助于理解劣化机制，并有助于识别潜在有益或不利的微生物群落及其基因组途径。在本研究中，我们证明了 是主要的细菌门，并且从 2016 年到 2017 年呈增加趋势，而 呈下降趋势。除了蓝藻和真菌引起的美学劣化外，主要由 CaCO3 组成的白色斑块，可能是由 和 引起的，也被认为是石质文物的另一个威胁。我们表明，微生物种群变化与地理位置之间没有显著相关性。特定的功能基因和途径也在特定的细菌物种中富集。由一群本土的碳酸盐生成细菌诱导的 CaCO3 沉淀也为石质文物的保护提供了一种自我接种方法。
