Björnham Oscar, Fällman Erik, Axner Ove, Ohlsson Jörgen, Nilsson Ulf J, Borén Thomas, Schedin Staffan
Umeå University, Department of Applied Physics and Electronics, SE-901 87 Umeå, Sweden.
J Biomed Opt. 2005 Jul-Aug;10(4):44024. doi: 10.1117/1.1989227.
Helicobacter pylori is a world-wide spread bacterium that causes persistent infections and chronic inflammations that can develop into gastritis and peptic ulcer disease. It expresses several adhesin proteins on its surface that bind to specific receptors in the gastric epithelium. The most well-known adhesin is BabA, which has previously been shown to bind specifically to the fucosylated blood group antigen Lewis b (Leb). The adhesion forces between BabA and the Leb antigen are investigated in this work and assessed by means of optical tweezers. A model system for in situ measurements of the interaction forces between individual bacteria and beads coated with Leb is developed. It is found that the de-adhesion force in this model system, measured with a loading rate of approximately 100 pNs, ranges from 20 to 200 pN. The de-adhesion force appears predominantly as multiples of an elementary force, which is determined to 25+/-1.5 pN and identified as the unbinding force of an individual BabA-Leb binding. It is concluded that adhesion in general is mediated by a small number of bindings (most often 1 to 4) despite that the contact surface between the bacterium and the bead encompassed significantly more binding sites.
幽门螺杆菌是一种在全球广泛传播的细菌，可导致持续性感染和慢性炎症，进而发展为胃炎和消化性溃疡疾病。它在其表面表达多种粘附蛋白，这些蛋白可与胃上皮细胞中的特定受体结合。最著名的粘附蛋白是BabA，此前已证明它能特异性结合岩藻糖基化血型抗原Lewis b（Leb）。本研究通过光镊研究并评估了BabA与Leb抗原之间的粘附力。开发了一个用于原位测量单个细菌与包被Leb的珠子之间相互作用力的模型系统。结果发现，在该模型系统中，以约100 pNs的加载速率测量的去粘附力范围为20至200 pN。去粘附力主要表现为基本力的倍数，该基本力确定为25±1.5 pN，并被确定为单个BabA-Leb结合的解离力。得出的结论是，尽管细菌与珠子之间的接触表面包含明显更多的结合位点，但一般来说，粘附是由少数结合（最常见的是1至4个）介导的。
