Saito Takayuki, Ishihara Kazuyuki, Ryu Masahiro, Okuda Katsuji, Sakurai Kaoru
Department of Removable Prosthodontics and Gerodontology, Tokyo Dental College, Chiba, Japan.
Bull Tokyo Dent Coll. 2010;51(3):145-50. doi: 10.2209/tdcpublication.51.145.
Aggregatibactor actinomycetemcomitans colonizes human periodontal lesions and is implicated in both aggressive periodontitis and chronic periodontitis. Clinical isolated colonies of A. actinomycetemcomitans were rough type. The rough type has a remarkable ability to adhere tenaciously to solid surfaces and colonize firmly. Rough type colonies change into smooth type colonies during the course of repeated inoculation and biofilm-forming activity ceases. Adherence by A. actinomycetemcomitans is mediated by the tight-adherence (tad) gene locus, which includes flp, rcpA and rcpB. In this study, we investigated the relationship between its biofilm-forming ability and expression of the flp, rcpA and rcpB genes associated with fimbriae protein production. First, we changed rough type strain organized biofilm on glass into smooth type and confirmed it by observation of biofilm on glass surfaces. Then, we carried out Real-Time PCR and found that expression of the rcpA and rcpB genes was clearly reduced in smooth type colonies. This suggests that expression of rcpA and rcpB plays a key role in biofilm formation by A. actinomycetemcomitans strains and the establishment of persistent infections in periodontal lesions.
伴放线聚集杆菌定殖于人类牙周病变部位，与侵袭性牙周炎和慢性牙周炎均有关联。临床分离的伴放线聚集杆菌菌落为粗糙型。粗糙型具有显著的紧密黏附于固体表面并牢固定殖的能力。在反复传代接种过程中，粗糙型菌落会转变为光滑型菌落，且生物膜形成活性停止。伴放线聚集杆菌的黏附由紧密黏附（tad）基因座介导，该基因座包括flp、rcpA和rcpB。在本研究中，我们调查了其生物膜形成能力与参与菌毛蛋白产生的flp、rcpA和rcpB基因表达之间的关系。首先，我们将在玻璃上形成生物膜的粗糙型菌株转变为光滑型，并通过观察玻璃表面的生物膜进行确认。然后，我们进行了实时荧光定量PCR，发现rcpA和rcpB基因在光滑型菌落中的表达明显降低。这表明rcpA和rcpB的表达在伴放线聚集杆菌菌株的生物膜形成以及牙周病变中持续性感染的建立中起关键作用。
