Abstract

Previous work in the authors’ lab demonstrated that tea extracts significantly suppressed streptococcal colonization of abiotic substrata by coating the bacterial cell surfaces with tea components. In this study, the physico-chemical mechanisms by which the tea coating inhibits cellular attachment are demonstrated. The changes in the cell surface physico-chemical properties of streptococci, induced by tea extracts, were measured. Using these results, surface interaction energies were calculated between streptococcal cells and hard surfaces (glass, stainless steel, hydroxyapatite and titanium) within the cellular attachment system exploiting the extended Derjaguin-Landau-Verwey-Overbeek theory. The net energy outcomes were compared with experiment results of attachment assays to validate the predictability of the model. The results showed that the tea extracts inhibited the attachment of the bacteria by 11.1%–91.5%, and reduced the interaction energy by 15.4%–94.9%. It was also demonstrated that the abilities of the bacteria to attach to hard surfaces correlated well with their net interaction energies. The predominant interaction in the systems was found to be hydrogen bonding. In conclusion, tea extracts suppress streptococcal attachment to hard substrata by limiting the formation of hydrogen bonds.

摘要

作者实验室之前的工作表明，茶提取物通过在细菌细胞表面涂上茶成分，显着抑制了非生物基质的链球菌定植。在这项研究中，证明了茶涂层抑制细胞附着的物理化学机制。测定了由茶提取物引起的链球菌细胞表面理化性质的变化。利用这些结果，利用扩展的 Derjaguin-Landau-Verwey-Overbeek 理论计算了细胞附着系统内链球菌细胞和硬表面（玻璃、不锈钢、羟基磷灰石和钛）之间的表面相互作用能。将净能量结果与附件测定的实验结果进行比较，以验证模型的可预测性。结果表明，茶提取物抑制了细菌的附着11.1%~91.5%，降低了相互作用能15.4%~94.9%。还证明了细菌附着在硬表面上的能力与其净相互作用能密切相关。发现系统中的主要相互作用是氢键。总之，茶提取物通过限制氢键的形成来抑制链球菌对硬基质的附着。