Distinct Binding Interactions of αβ-Integrin and Proteoglycans with Fibronectin.

Dynamic single-molecule force spectroscopy was performed to monitor the unbinding of fibronectin with the proteoglycans syndecan-4 (SDC4) and decorin and to compare this with the unbinding characteristics of αβ-integrin. A single energy barrier was sufficient to describe the unbinding of both SDC4 and decorin from fibronectin, whereas two barriers were observed for the dissociation of αβ-integrin from fibronectin. The outer (high-affinity) barriers in the interactions of fibronectin with αβ-integrin and SDC4 are characterized by larger barrier heights and widths and slower dissociation rates than those of the inner (low-affinity) barriers in the interactions of fibronectin with αβ-integrin and decorin.

Reduced curvilinear velocity of boar sperm on substrates with increased hydrophobicity.

The curvilinear velocity (VCL) of boar spermatozoa between standard microscopy glassware decreases when the slides are coated with the hydrophobic polymer polystyrene (PS) compared with the less hydrophobic poly(methyl methacrylate) (PMMA) coating. Sperm from three boars were observed and analyzed using particle tracking software. The VCL did not differ significantly between coatings of different thickness, indicating no penetration of the sperm into the coating and that only the surface layer of the polymer film interacts with the sperm and buffer medium.