Acidogenic Potential of Oral Bifidobacterium and Its High Fluoride Tolerance
Acidogenic Potential of Oral Bifidobacterium and Its High Fluoride Tolerance
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DOI：
10.3389/fmicb.2019.01099
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发表时间：
2019-05-16
影响因子：
5.2
通讯作者：
Takahashi, Nobuhiro
中科院分区：
文献类型：
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作者：
Manome, Ayumi;Abiko, Yuki;Takahashi, Nobuhiro
双歧杆菌经常在幼儿龋齿和白色斑点病变中检测到，表明它是一种新型的龋齿相关细菌。已知双歧杆菌具有独特的代谢途径，即“双歧杆菌分流”，这可能通过增加其产酸而赋予其致龋潜力。因此，我们评估了双歧杆菌的产酸活性及其对防龋剂氟的敏感性。使用长双歧杆菌、齿双歧杆菌和变形链球菌。在厌氧条件下，在不存在和存在氟化物的情况下，使用pH统计仪测量产酸活性。此外，代谢组学分析进行阐明的机制，氟的抑制作用。双歧杆菌在pH5.5时的产酸量与在pH7.0时的产酸量一样高，表明双歧杆菌具有高的致龋潜力，尽管其产酸量低于S.变种人此外，双歧杆菌在缺乏胞外碳水化合物的情况下产酸，这表明它可以储存胞内多糖。双歧杆菌从乳糖比从葡萄糖产生更多的酸。双歧杆菌主要产生乙酸，而S.变形菌主要产生乳酸。氟对双歧杆菌产酸的半数抑制浓度（IC_（50））比S.变种人氟抑制糖酵解中的烯醇化酶，导致3-磷酸烯醇丙酮酸、6-磷酸葡萄糖和4-磷酸赤藓糖的细胞内积累。然而，双歧杆菌分流提供了一个旁路途径，可以用来产生乙酸，这表明双歧杆菌能够代谢碳水化合物在氟化物的存在。这表明，它的独家乙酸生产有助于龋齿的发病机制。
Bifidobacterium is frequently detected in early childhood caries and white spot lesions, indicating that it is a novel caries-associated bacterium. Bifidobacterium is known to possess a unique metabolic pathway, the "bifid shunt," which might give it cariogenic potential by increasing its acid production. Thus, we evaluated the acid-producing activity of Bifidobacterium and its sensitivity to fluoride, a caries preventive reagent. Bifidobacterium longum, Bifidobacterium dentium, and Streptococcus mutans were used. Acid-producing activity was measured using a pH-stat in the absence and presence of fluoride under anaerobic conditions. Furthermore, metabolomic analysis was performed to elucidate the mechanism underlying the inhibitory effects of fluoride. The acid production of Bifidobacterium at pH 5.5 was as high as that seen at pH 7.0, indicating that Bifidobacterium has high cariogenic potential, although it produced less acid than S. mutans. In addition, Bifidobacterium produced acid in the absence of extracellular carbohydrates, suggesting that it can store intracellular polysaccharides. Bifidobacterium produced more acid from lactose than from glucose. Bifidobacterium mainly produced acetate, whereas S. mutans mainly produced lactate. The 50% inhibitory concentration (IC50) of fluoride for acid production was 6.0-14.2 times higher in Bifidobacterium than in S. mutans. Fluoride inhibited enolase in the glycolysis, resulting in the intracellular accumulation of 3-phosphoenolpyruvate, glucose 6-phosphate, and erythrose 4-phosphate. However, the bifid shunt provides a bypass pathway that can be used to produce acetate, suggesting that Bifidobacterium is able to metabolize carbohydrates in the presence of fluoride. It is suggested that its exclusive acetate production contributes to the pathogenesis of dental caries.