Touhami, Ahmed
[UCL]
Hoffmann, Barbara
[Zurich]
Vasella, Andrea
[Zurich]
Denis, Frédéric
[UCL]
Dufrêne, Yves
[UCL]
Aggregation of microbial cells mediated by specific interactions plays a pivotal role in the natural environment, in medicine and in biotechnological processes. Here we used atomic force microscopy (AFM) to measure individual lectin-carbohydrate interactions involved in the flocculation of yeast cells, an aggregation event of crucial importance in fermentation technology. AFM probes functionalized with oligoglucose carbohydrates were used to record force-distance curves on living yeast cells at a rate of 0.5 micro m s(-1). Flocculating cells showed adhesion forces of 121+/-53 pN, reflecting the specific interaction between individual cell-surface lectins and glucose residues. Similar adhesion forces, 117+/-41 pN, were measured using probes functionalized with the lectin concanavalin A and attributed to specific binding to cell-surface mannose residues. By contrast, specific interaction forces were not observed in non-flocculating conditions, i.e. in the presence of mannose or when using non-flocculating cells, pointing to their involvement in yeast flocculation. The single molecule force spectroscopy measurements presented here provide a means to study a variety of cellular interactions at the molecular level, such as the adhesion of bacteria to animal and plant tissues.
Bibliographic reference |
Touhami, Ahmed ; Hoffmann, Barbara ; Vasella, Andrea ; Denis, Frédéric ; Dufrêne, Yves. Aggregation of yeast cells: direct measurement of discrete lectin-carbohydrate interactions.. In: Microbiology (Reading, England), Vol. 149, no. Pt 10, p. 2873-8 (2003) |
Permanent URL |
http://hdl.handle.net/2078.1/9638 |