The adhesive plaques of Mytilus byssus are investigated increasingly to determine the molecular requirements for wet adhesion. Mfp-2 is the most abundant protein in the plaques, but little is known about its function. Analysis of Mfp-2 films using the surface forces apparatus detected no interaction between films or between a film and bare mica; however, addition of Ca2+ and Fe3+ induced significant reversible bridging (work of adhesion Wad ≈ 0.3 mJ/m2 to 2.2 mJ/m2) between two films at 0.35 m salinity. The strongest observed Fe3+-mediated bridging approaches the adhesion of oriented avidin-biotin complexes. Raman microscopy of plaque sections supports the co-localization of Mfp-2 and iron, which interact by forming bis- or tris-DOPA-iron complexes. Mfp-2 adhered strongly to Mfp-5, a DOPA-rich interfacial adhesive protein, but not to another interfacial protein, Mfp-3, which may in fact displace Mfp-2 from mica. In the presence of metal ions or Mfp-5, Mfp-2 adhesion was fully reversible. These results suggest that plaque cohesiveness depends on Mfp-2 complexation of metal ions, particularly Fe3+ and also by Mfp-2 interaction with Mfp-5 at the plaque-substratum interface.

Scalp involvement is a prominent and often the initial presentation in patients with psoriasis. Hair growth may be impaired with a hair loss and an increased telogen/anagen ratio. The aim of this study was to investigate the hair density and anagen/telogen ratio in psoriatic patients, using epiluminescence microscopy combined with digital image analysis (TrichoScan). Thirty psoriatic patients with scalp involvement and the same number of clinically healthy individuals were included in the study. For the measurement of hair density, anagen/telogen ratio and number of terminal and vellus hairs, a commercially available software TrichoScan was used. Hair density measurements did not show significant difference between patients and controls (P=0.05). The anagen ratio was significantly lower and telogen ratio significantly higher in psoriasis patients than in controls (P<0.01 both). There was no correlation between hair parameters and patient age or duration of disease. Study results support the evidence that scalp psoriasis is associated with an increased telogen/anagen ratio.