Periodontitis is a major cause of tooth loss in adults that initially results from dental plaque. Subgingival plaque pathogenesis is affected by both community composition and plaque structures, although limited data are available concerning the latter. To bridge this knowledge gap, subgingival plaques were obtained using filter paper (the fourth layer) and curette (the first-third layers) sequentially and the phylogenetic differences between the first-third layers and the fourth layer were characterized by sequencing the V3-V4 regions of 16S rRNA. A total of 11 phyla, 148 genera, and 308 species were obtained by bioinformatic analysis, and no significant differences between the operational taxonomic unit numbers were observed for these groups. In both groups, the most abundant species were Porphyromonas gingivalis and Fusobacterium nucleatum. Actinomyces naeslundii, Streptococcus intermedius, and Prevotella intermedia possessed relatively high proportions in the first-third layers; while in the fourth layer, both traditional pathogens (Treponema denticola and Campylobacter rectus) and novel pathobionts (Eubacterium saphenum, Filifactor alocis, Treponema sp. HOT238) were prominent. Network analysis showed that either of them exhibited a scale-free property and was constructed by two negatively correlated components (the pathogen component and the nonpathogen component), while the synergy in the nonpathogen component was lower in the first-third layers than that in the fourth layer. After merging these two parts into a whole plaque group, the negative/positive correlation ratio increased. With potential connections, the first-third layers and the fourth layer showed characteristic key nodes in bacterial networks.

中文翻译：

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测量牙周炎患者的龈下微生物群：比较表层和下层。

牙周炎是成年人牙齿脱落的主要原因，最初是由牙菌斑引起的。龈下菌斑的发病机理受群落组成和菌斑结构的影响，尽管有关后者的数据有限。为了弥合这一知识鸿沟，依次使用滤纸（第四层）和刮匙（第一至第三层）获得龈下菌斑，并通过对V3-V4进行测序来表征第一至第三层和第四层之间的系统发育差异16S rRNA区域。通过生物信息学分析总共获得了11个门，148个属和308个物种，这些组的操作分类单位数之间没有显着差异。在这两组中，最丰富的物种是牙龈卟啉单胞菌和核梭菌。内生放线菌，中间链球菌和中间小球藻在前三层中占有相对较高的比例。而在第四层中，传统病原体（牙垢小球菌和直弯曲弯曲杆菌）和新型病原菌（隐孢子虫，丝线虫，螺旋体菌HOT238）均很突出。网络分析表明，它们中的任何一个都表现出无鳞性质，并且由两个负相关的成分（病原体成分​​和非病原体成分​​）构成，而在第一到第三层中，非病原体成分​​中的协同作用比在前三层中低。第四层。将这两部分合并成一个完整的斑块组后，负/正相关比增加。有了潜在的联系，