Liang M N, Smith S P, Metallo S J, Choi I S, Prentiss M, Whitesides G M
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
Proc Natl Acad Sci U S A. 2000 Nov 21;97(24):13092-6. doi: 10.1073/pnas.230451697.
Mechanisms of bacterial pathogenesis have become an increasingly important subject as pathogens have become increasingly resistant to current antibiotics. The adhesion of microorganisms to the surface of host tissue is often a first step in pathogenesis and is a plausible target for new antiinfective agents. Examination of bacterial adhesion has been difficult both because it is polyvalent and because bacterial adhesins often recognize more than one type of cell-surface molecule. This paper describes an experimental procedure that measures the forces of adhesion resulting from the interaction of uropathogenic Escherichia coli to molecularly well defined models of cellular surfaces. This procedure uses self-assembled monolayers (SAMs) to model the surface of epithelial cells and optical tweezers to manipulate the bacteria. Optical tweezers orient the bacteria relative to the surface and, thus, limit the number of points of attachment (that is, the valency of attachment). Using this combination, it was possible to quantify the force required to break a single interaction between pilus and mannose groups linked to the SAM. These results demonstrate the deconvolution and characterization of complicated events in microbial adhesion in terms of specific molecular interactions. They also suggest that the combination of optical tweezers and appropriately functionalized SAMs is a uniquely synergistic system with which to study polyvalent adhesion of bacteria to biologically relevant surfaces and with which to screen for inhibitors of this adhesion.
随着病原体对现有抗生素的耐药性日益增强，细菌致病机制已成为一个越来越重要的课题。微生物黏附于宿主组织表面通常是致病的第一步，也是新型抗感染药物的一个合理靶点。细菌黏附的研究一直很困难，这既是因为其具有多价性，也是因为细菌黏附素通常能识别不止一种类型的细胞表面分子。本文描述了一种实验方法，该方法用于测量尿路致病性大肠杆菌与分子定义明确的细胞表面模型相互作用所产生的黏附力。该方法使用自组装单分子层（SAMs）来模拟上皮细胞表面，并使用光镊来操控细菌。光镊使细菌相对于表面定向，从而限制附着点的数量（即附着的价数）。通过这种组合，能够量化破坏菌毛与连接到SAM的甘露糖基团之间单个相互作用所需的力。这些结果证明了根据特定分子相互作用对微生物黏附中复杂事件进行反卷积和表征。它们还表明，光镊和功能适当的SAMs的组合是一个独特的协同系统，可用于研究细菌与生物相关表面的多价黏附，并用于筛选这种黏附的抑制剂。
