Applying high-throughput rRNA gene sequencing to assess microbial contamination of a 40-year old exposed archaeological profile
Applying high-throughput rRNA gene sequencing to assess microbial contamination of a 40-year old exposed archaeological profile
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DOI：
10.1016/j.jas.2020.105308
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发表时间：
2020
影响因子：
2.8
通讯作者：
Daniel S. Jones;G. Monnier;Aspen Cooper;Mile Baković;Goran Pajović;Nikola Borovinić;G. Tostevin
中科院分区：
文献类型：
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作者：
Daniel S. Jones;G. Monnier;Aspen Cooper;Mile Baković;Goran Pajović;Nikola Borovinić;G. Tostevin
近年来，从考古学背景中恢复古代有机分子的工作激增。这些分析为人类进化和文化实践提供了前所未有的见解，并为重建古环境提供了宝贵的数据。然而，微生物对考古沉积物的污染可能会改变古代生物分子数据。此外，微生物能够在多大程度上渗透古代考古沉积物，一旦这些被挖掘暴露出来，是未知的。我们在黑山迪纳拉阿尔卑斯山的一个岩石庇护所Crvena斯蒂耶纳测试了这个问题，它包含了超过80，000年的考古沉积。在20世纪60年代早期，这些剖面被清理了几次，以便进行考古、地质和生物分子分析。清洁后暴露的型材上生长的绿色生物膜引发了这样一个问题，即这种表面污染是否延伸到型材中。为了测试这个问题，我们检查了五个不同的地质层，从暴露的表面，并在1厘米的间隔水平到剖面的沉积物采样。16S rRNA基因测序结果表明，沉积物表面的样品有不同的微生物群落，从大多数样品收集超过1厘米深，和更深的样品的微生物生物量是非常低的。总之，这一证据有力地表明微生物污染仅限于型材表面。这就降低了这些沉积物中的古老生物分子因原位微生物群落最近的变化而改变的可能性，而且取样前对剖面的清理可能不需要超过2厘米深。这些结果进一步支持有限的垂直采样沿着考古剖面和见证部分，一个战略，保存罕见的和有限的考古存款，同时帮助解决有关过去的关键问题的研究效用。
In recent years there has been a surge in the recovery of ancient organic molecules from archaeological contexts. These analyses are yielding unprecedented insights into human evolution and cultural practices, and are providing valuable data for reconstructing paleoenvironments. However, contamination of archaeological sediments by microorganisms can alter ancient biomolecular data. Furthermore, the extent to which microbes can penetrate ancient archaeological sediments once these are exposed by excavation is unknown. We tested this question at Crvena Stijena, a rock shelter in the Dinaric alps in Montenegro that contains archaeological deposits spanning more than 80,000 years. Excavations in the early 1960s exposed these profiles, which have been cleaned several times to permit sampling for archaeological, geological, and biomolecular analyses. The growth of green biofilms on the exposed profiles after cleaning has prompted the question of whether this surface contamination extends into the profile. To test this question, we examined five different geological layers by sampling sediments from the exposed surface and at 1 cm intervals horizontally into the profile. Results from 16S rRNA gene sequencing show that samples from sediment surfaces have distinct microbial communities from most samples collected more than 1 cm deep, and microbial biomass from the deeper samples is very low. Together, this evidence strongly indicates that microbial contamination is limited to the profile surfaces. This lowers the likelihood that ancient biomolecules in these sediments have been altered by recent changes to the in situ microbial community, and that cleaning of the profiles before sampling may not need to exceed 2 cm in depth. These results lend further support to the research utility of limited vertical sampling along archaeological profiles and witness sections, a strategy which conserves rare and limited archaeological deposits while helping to tackle key questions about the past.