Table_11_Comparison of Periodontal Bacteria of Edo and Modern Periods Using Novel Diagnostic Approach for Periodontitis With Micro-CT.xlsx

Ancient dental calculus, formed from dental plaque, is a rich source of ancient DNA and can provide information regarding the food and oral microbiology at that time. Genomic analysis of dental calculus from Neanderthals has revealed the difference in bacterial composition of oral microbiome between Neanderthals and modern humans. There are few reports investigating whether the pathogenic bacteria of periodontitis, a polymicrobial disease induced in response to the accumulation of dental plaque, were different between ancient and modern humans. This study aimed to compare the bacterial composition of the oral microbiome in ancient and modern human samples and to investigate whether lifestyle differences depending on the era have altered the bacterial composition of the oral microbiome and the causative bacteria of periodontitis. Additionally, we introduce a novel diagnostic approach for periodontitis in ancient skeletons using micro-computed tomography. Ancient 16S rDNA sequences were obtained from 12 samples at the Unko-in site (18th-19th century) of the Edo era (1603–1867), a characteristic period in Japan when immigrants were not accepted. Furthermore, modern 16S rDNA data from 53 samples were obtained from a database to compare the modern and ancient microbiome. The microbial co-occurrence network was analyzed based on 16S rDNA read abundance. Eubacterium species, Mollicutes species, and Treponema socranskii were the core species in the Edo co-occurrence network. The co-occurrence relationship between Actinomyces oricola and Eggerthella lenta appeared to have played a key role in causing periodontitis in the Edo era. However, Porphyromonas gingivalis, Fusobacterium nucleatum subsp. vincentii, and Prevotella pleuritidis were the core and highly abundant species in the co-occurrence network of modern samples. These results suggest the possibility of differences in the pathogens causing periodontitis during different eras in history.

由牙菌斑矿化形成的古牙结石是古代DNA的优质来源，可提供古代人类的饮食与口腔微生物学相关信息。对尼安德特人（Neanderthal）牙结石开展的基因组分析，已揭示其口腔微生物组的细菌组成与现代人类存在显著差异。目前鲜有研究探讨古代与现代人类的牙周炎（periodontitis）致病菌是否存在差异——牙周炎是一种由牙菌斑堆积诱发的多微生物感染性疾病。本研究旨在对比古今人类样本的口腔微生物组细菌组成，并探究不同时代的生活方式差异是否改变了口腔微生物组的细菌构成以及牙周炎的致病菌。此外，本研究还提出了一种基于微型计算机断层扫描（micro-computed tomography）的古代骨骼牙周炎全新诊断方法。本研究从日本江户时代（1603–1867，彼时为日本不接纳外来移民的典型历史时期）运光院（Unko-in）遗址的12份样本中，获取了古代16S rDNA序列。此外，本研究从公共数据库中获取了53份现代样本的16S rDNA数据，用于与古代微生物组进行对比分析。本研究基于16S rDNA序列读长丰度，对微生物共现网络进行了分析。结果显示，真杆菌属（Eubacterium）物种、柔膜菌纲（Mollicutes）物种以及索氏密螺旋体（Treponema socranskii）为江户时代微生物共现网络的核心物种；奥氏放线菌（Actinomyces oricola）与迟缓埃格特菌（Eggerthella lenta）之间的共现关系，在江户时代牙周炎的发病过程中发挥了关键作用。然而，牙龈卟啉单胞菌（Porphyromonas gingivalis）、具核梭杆菌文森特亚种（Fusobacterium nucleatum subsp. vincentii）以及胸膜普雷沃菌（Prevotella pleuritidis）则是现代样本微生物共现网络中的核心且高丰度物种。本研究结果提示，历史不同时期的牙周炎致病菌可能存在差异。