Nanomechanical properties of glucans and associated cell-surface adhesion of Streptococcus mutans probed by atomic force microscopy under in situ conditions
Nanomechanical properties of glucans and associated cell-surface adhesion of Streptococcus mutans probed by atomic force microscopy under in situ conditions
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DOI：
10.1099/mic.0.2007/007625-0
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发表时间：
2007-09-01
期刊：
影响因子：
2.8
通讯作者：
Gimzewski, James K.
中科院分区：
文献类型：
--
作者：
Cross, Sarah E.;Kreth, Jens;Gimzewski, James K.
本研究使用原子力显微镜（AFM）来探测与变形链球菌的葡聚糖聚合物相关的局部细胞表面相互作用，变形链球菌的葡聚糖聚合物是最常归因于该微生物的毒力的大分子。原位力谱用于定量探测和关联细胞表面粘附和动力学与S。mutans UA 140野生型和五种葡糖基转移酶突变体。牙面与S.变形杆菌主要通过三种葡糖基转移酶（Gtfs; GtfB、GtfC和GtfD）从蔗糖产生葡聚糖来介导。为了监测这些特殊的Gtfs的贡献，S.通过特定基因失活构建变异株，并在蔗糖和非蔗糖条件下与野生型进行比较。我们报告直接测量与葡聚糖大分子相关的机械性能，表明局部粘附强度在时间依赖性过程中增加，破裂事件的平均数量减少。这一发现表明S.在蔗糖存在的情况下，变形多糖主要通过葡聚糖附着到表面。此外，Gtf蛋白在蔗糖非依赖性附着中的可能作用得到了GtfBCD突变体与野生型相比粘附性能降低的支持。
This study used atomic force microscopy (AFM) to probe the local cell-surface interactions associated with the glucan polymers of Streptococcus mutans, the macromolecules most commonly attributed to the virulence of this microbe. In situ force spectroscopy was used to quantitatively probe and correlate cell-surface adhesion and dynamics with S. mutans UA140 wild-type and five glucosyltransferase mutants. Adhesion between the tooth surface and S. mutans is largely mediated by glucan production from sucrose via three glucosyltransferases (Gtfs; GtfB, GtfC and GtfD). To monitor the contribution of these particular Gtfs, isogenic mutants of S. mutans were constructed by specific gene inactivation and compared to the wild-type under sucrose and non-sucrose conditions. We report direct measurement of the mechanical properties associated with glucan macromolecules demonstrating that the local adhesion strength increases in a time-dependent process, with a decrease in the average number of rupture events. This finding suggests that S. mutans attaches mainly through glucans to surfaces in the presence of sucrose. In addition, a possible role of the Gtf proteins in sucrose-independent attachment is supported by the decreased adhesion properties of the GtfBCD mutant compared to the wild-type.