Mechanisms of inhibition by fluoride of urease activities of cell suspensions and biofilms of Staphylococcus epidermidis, Streptococcus salivarius, Actinomyces naeslundii and of dental plaque.
Mechanisms of inhibition by fluoride of urease activities of cell suspensions and biofilms of Staphylococcus epidermidis, Streptococcus salivarius, Actinomyces naeslundii and of dental plaque.
复制标题
氟化物抑制表皮葡萄球菌、唾液链球菌、内氏放线菌和牙菌斑细胞悬浮液和生物膜脲酶活性的机制。
DOI：
10.1111/j.1399-302x.2005.00228.x
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Marquis,RE
中科院分区：
文献类型：
--
作者：
Barboza-Silva,E;Castro,ACD;Marquis,RE
背景/目的：已知氟化物是一种有效的细菌尿素酶抑制剂，也可以氢氟酸的形式作为跨膜质子导体，酸化完整细胞的细胞质，并可能间接抑制尿素酶。我们的研究目的是评估氟化物对口腔中常见的三种尿素酶阳性细菌的抑制效力，并确定直接和间接抑制尿素酶对完整细胞或生物膜的总体抑制的相对重要性。方法：实验设计涉及悬浮液中的完整细菌、单一生物体生物膜、细胞提取物和牙菌斑。结果：我们发现，在0.1-0.5 mmin的菌斑水平下，氟化物以pH依赖性方式抑制表皮葡萄球菌、唾液链球菌或内氏放线菌悬浮液或单生物生物膜中细胞的尿素分解。 有机弱酸吲哚美辛和癸酸的实验结果表明，导致细胞质酸化的弱酸效应也参与了氟化物的抑制作用。然而，在酸性环境中，脲酶的直接氟抑制似乎是降低尿素分解活性的主要机制。新鲜采集的龈上牙菌斑的实验结果表明，对氟化物的反应与S。结论：氟化物可通过直接和间接机制减少口腔细菌从尿素中产碱。
Background/aims:Fluoride is known to be a potent inhibitor of bacterial ureases and can also act in the form of hydrofluoric acid as a transmembrane proton conductor to acidify the cytoplasm of intact cells with possible indirect, acid inhibition of urease. Our research objectives were to assess the inhibitory potencies of fluoride for three urease‐positive bacteria commonly found in the mouth and to determine the relative importance of direct and indirect inhibition of ureases for overall inhibition of intact cells or biofilms.Methods:The experimental design involved intact bacteria in suspensions, mono‐organism biofilms, cell extracts, and dental plaque. Standard enzymatic assays for ammonia production from urea were used.Results:We found that ureolysis by cells in suspensions or mono‐organism biofilms ofStaphylococcus epidermidis,Streptococcus salivariusorActinomyces naeslundiiwas inhibited by fluoride at plaque levels of 0.1–0.5 mmin a pH‐dependent manner. The results of experiments with the organic weak acids indomethacin and capric acid, which do not directly inhibit urease enzyme, indicated that weak‐acid effects leading to cytoplasmic acidification are also involved in fluoride inhibition. However, direct fluoride inhibition of urease appeared to be the major mechanism for reduction in ureolytic activity in acid environments. Results of experiments with freshly harvested supragingival dental plaque indicated responses to fluoride similar to those ofS. salivariuswith pH‐dependent fluoride inhibition and both direct and indirect inhibition of urease.Conclusion:Fluoride can act to diminish alkali production from urea by oral bacteria through direct and indirect mechanisms.