Role of coaggregation among periodontopathic bacteria in formation of periodontopathic biofilm

目的：牙周炎是由革兰氏阴性杆菌和螺旋体引起的。牙龈卟啉单胞菌（Porphyromonas gingivalis）是慢性牙周病的主要致病菌，具有多种毒力因子，包括菌毛、脂多糖和蛋白酶，常与Tannerella gingivensis和Treponema denticola共分离。这三种微生物的结合被称为“红色复合物”，并且被认为在慢性牙周炎的进展中起重要作用。在这个项目中，我们研究了这些牙周病细菌之间的共聚集和协同效应，以阐明牙周病生物膜形成的潜在机制。材料和方法：通过在共聚集缓冲液中660 nm处的吸光度来评估牙龈卟啉单胞菌ATCC 33277和齿垢毛癣菌ATCC 35405之间的共聚集。为了阐明哪些牙龈卟啉单胞菌配体参与共聚集，构建了缺乏牙龈卟啉单胞菌蛋白酶和菌毛的敲除突变体。协同效应 ...更多信息 结果与讨论：Mfa 1缺陷型、Kgp、RgpA和RgpB缺陷型和Kgp、RgpA和HagA缺陷型的牙龈卟啉单胞菌与齿垢毛癣菌的共聚集反应减弱。这些结果表明，牙龈卟啉酶和Mfa 1参与了共聚集反应。特别地，在Kgp、RgpA和RgpB缺陷型菌株和Kgp、RgpA和HagA缺陷型菌株中活性显著降低。此外，在Mfa 1 FimA突变体中观察到共聚集活性。这表明牙龈卟啉菌蛋白酶和HagA的血凝素/粘附结构域在共聚集反应中起关键作用。使用我们的双室系统，具核梭杆菌在与牙龈卟啉单胞菌共培养中的生物膜形成比单独培养获得的生物膜形成增加约4倍。综上所述，这些结果表明，牙龈卟啉单胞菌与其他牙周病原体的共聚集反应不仅参与了龈沟生物膜的定植，而且还参与了牙周病生物膜的形成。少

Objects : Periodontitis is caused by Gram-negative rods and spirochetes. Porphyromonas gingivalis is a major pathogen of chronic periodontal disease, This microorganism has a number of virulence factors, including fimbriae, lipopolysaccharides and proteases, and is often co-isolated with Tannerella forsythensis and Treponema denticola. The combination of these three microorganisms is known as the "red complex", and is thought to play an important role in the progression of chronic periodontitis. In this project, we investigated coaggregation and synergistic effects among these periodontopathic bacteria to clarify the underlying mechanisms of periodontopathic biofilm formation.Materials and Methods : Coaggregation between P.gingivalis ATCC 33277 and T.denticola ATCC 35405 was evaluated by absorbance at 660 nm in coaggregation buffer. To clarify which P.gingivalis ligands were involved in coaggregation, knockout mutants lacking gingipains and fimbriae were constructed. Synergistic effect … More s on biofilm formation were evaluated by using a two-compartment co-culture system incorporating a 0.4 m filter unit.Results and Discussion : Coaggregation reaction between P.gingivalis and T.denticola was decreased in the Mfa1 deficient mutant, kgp, RgpA and RgpB deficient mutant and Kgp, RgpA and HagA deficient mutant. These results indicated that gingipains and Mfa1 were involved in the coaggregation reaction. In particular, activity decreased significantly in the Kgp, RgpA and RgpB deficient strain and Kgp, RgpA and HagA deficient strain. In addition, coaggregation activity was observed in the Mfa1 FimA mutant. This suggests that the hemagglutinin/ahesion domains of gingipains and HagA play a key role in the coaggregation reaction. Using our two-compartment system, Fusobacterium nucleatum showed an approximately four-fold increase in biofilm formation in co-culture with P.gingivalis compared with that obtained with single culture alone. Taken together, these results suggest that the coaggregation reaction of P.gingivalis with other periodontopathogens is involved not only in the colonization of gingival crevicular biofilms, but also in the formation of periodontopathic biofilms. Less