Actinomyces oris is an early colonizer and has two types of fimbriae on its cell surface, type 1 fimbriae (FimP and FimQ) and type 2 fimbriae (FimA and FimB), which contribute to the attachment and coaggregation with other bacteria and the formation of biofilm on the tooth surface, respectively. Short-chain fatty acids (SCFAs) are metabolic products of oral bacteria including A. oris and regulate pH in dental plaques. To clarify the relationship between SCFAs and fimbrillins, effects of SCFAs on the initial attachment and colonization (INAC) assay using A. oris wild type and fimbriae mutants was investigated. INAC assays using A. oris MG1 strain cells were performed with SCFAs (acetic, butyric, propionic, valeric and lactic acids) or a mixture of them on human saliva-coated 6-well plates incubated in TSB with 0.25% sucrose for 1 h. The INAC was assessed by staining live and dead cells that were visualized with a confocal microscope. Among the SCFAs, acetic, butyric and propionic acids and a mixture of acetic, butyric and propionic acids induced the type 1 and type 2 fimbriae-dependent and independent INAC by live A. oris, but these cells did not interact with streptococci. The main effects might be dependent on the levels of the non-ionized acid forms of the SCFAs in acidic stress conditions. GroEL was also found to be a contributor to the FimA-independent INAC by live A. oris cells stimulated with non-ionized acid. SCFAs affect the INAC-associated activities of the A. oris fimbrillins and non-fimbrillins during ionized and non-ionized acid formations in the form of co-culturing with other bacteria in the dental plaque but not impact the interaction of A. oris with streptococci.

中文翻译：

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短链脂肪酸诱导 1 型和 2 型纤毛蛋白依赖性和纤毛蛋白独立的初始附着和定植，但不与链球菌共培养

口放线菌是早期定殖菌，其细胞表面有两种菌毛，1 型菌毛（FimP 和 FimQ）和 2 型菌毛（FimA 和 FimB），它们有助于与其他细菌的附着和共聚以及生物膜的形成分别在牙齿表面。短链脂肪酸 (SCFA) 是口腔细菌（包括 A. oris）的代谢产物，可调节牙菌斑中的 pH 值。为了阐明 SCFAs 和纤毛蛋白之间的关系，研究了 SCFAs 对使用 A. oris 野生型和纤毛突变体的初始附着和定植 (INAC) 测定的影响。使用短链脂肪酸（乙酸、丁酸、丙酸、戊酸和乳酸）或它们的混合物在人唾液包被的 6 孔板上使用 A. oris MG1 菌株细胞进行 INAC 测定，在含有 0.25% 蔗糖的 TSB 中孵育 1 小时。通过对用共聚焦显微镜观察的活细胞和死细胞进行染色来评估 INAC。在 SCFAs 中，乙酸、丁酸和丙酸以及乙酸、丁酸和丙酸的混合物通过活的 A. oris 诱导 1 型和 2 型菌毛依赖和独立的 INAC，但这些细胞不与链球菌相互作用。主要影响可能取决于酸性胁迫条件下 SCFA 的非电离酸形式的水平。还发现 GroEL 是由非电离酸刺激的活 A. oris 细胞产生的不依赖于 FimA 的 INAC 的贡献者。SCFA 以与牙菌斑中其他细菌共培养的形式，在电离和非电离酸形成过程中影响 A. oris fimbrillins 和非纤毛蛋白的 INAC 相关活性，但不影响 A. oris fimbrillins 和非纤毛蛋白的相互作用。