Background

The opportunistic pathogens Fusobacterium nucleatum and Porphyromonas gingivalis are Gram-negative bacteria associated with oral biofilm and periodontal disease. This study investigated interactions between F. nucleatum and P. gingivalis proteomes with the objective to identify proteins relevant in biofilm formation.

Methods

We applied liquid chromatography-tandem mass spectrometry to determine the expressed proteome of F. nucleatum and P. gingivalis cells grown in biofilm or planktonic culture, and as mono- and dual-species models. The detected proteins were classified into functional categories and their label-free quantitative (LFQ) intensities statistically compared.

Results

The proteomic analyses detected 1,322 F. nucleatum and 966 P. gingivalis proteins, including abundant virulence factors. Using univariate statistics, we identified significant changes between biofilm and planktonic culture (p-value ≤0.05) in 0,4% F. nucleatum, 7% P. gingivalis, and 14% of all proteins in the dual-species model. For both species, proteins involved in vitamin B2 (riboflavin) metabolism had significantly increased levels in biofilm. In both mono- and dual-species biofilms, P. gingivalis increased the production of proteins for translation, oxidation-reduction, and amino acid metabolism compared to planktonic cultures. However, when we compared LFQ intensities between mono- and dual-species, over 90% of the significantly changed P. gingivalis proteins had their levels reduced in biofilm and planktonic settings of the dual-species model.

Conclusions

The findings suggest that P. gingivalis reduces the production of multiple proteins because of the F. nucleatum presence. The results highlight the complex interactions of bacteria contributing to oral biofilms, which need to be considered in the design of prevention strategies.

中文翻译：

---

口腔细菌具核梭杆菌和牙龈卟啉单胞菌的无标记定量蛋白质组学分析，以确定与生物膜形成相关的蛋白质特征

背景

机会性病原体具核梭杆菌和牙龈卟啉单胞菌是与口腔生物膜和牙周病相关的革兰氏阴性细菌。本研究调查了具核梭菌和牙龈卟啉单胞菌蛋白质组之间的相互作用，目的是鉴定与生物膜形成相关的蛋白质。

方法

我们应用液相色谱-串联质谱法来确定在生物膜或浮游培养中生长的F. nucleatum和P. gingivalis细胞的表达蛋白质组，并作为单物种和双物种模型。将检测到的蛋白质分类为功能类别，并对其无标记定量 (LFQ) 强度进行统计学比较。

结果

蛋白质组学分析检测到 1,322个 F. nucleatum和 966个P. gingivalis蛋白质，包括丰富的毒力因子。使用单变量统计，我们确定了双物种模型中 0.4% F. nucleatum、7%牙龈卟啉单胞菌和 14% 的所有蛋白质中生物膜和浮游培养之间的显着变化（p 值 ≤0.05）。对于这两个物种，参与维生素 B2（核黄素）代谢的蛋白质在生物膜中的水平显着增加。在单种和双种生物膜中，牙龈卟啉单胞菌与浮游培养物相比，增加了用于翻译、氧化还原和氨基酸代谢的蛋白质产量。然而，当我们比较单物种和双物种之间的 LFQ 强度时，超过 90% 的显着变化的牙龈卟啉单胞菌蛋白在双物种模型的生物膜和浮游环境中的水平降低。

结论

研究结果表明，由于有核梭菌的存在，牙龈卟啉单胞菌减少了多种蛋白质的产生。结果突出了导致口腔生物膜的细菌的复杂相互作用，需要在设计预防策略时加以考虑。