The zonular filaments from the eyes of cows are rich in microfibrils containing fibrillin. Tensile tests, stress-relaxation tests and X-ray diffraction studies were used to study the relationship between the mechanical behaviour of zonular filaments and the molecular packing and structure of the fibrillin-rich microfibrils. Zonular filaments show a non-linear (J-shaped) stress-strain curve and appreciable stress-relaxation. It is proposed that the non-linear properties are due to local variations in waviness in the microfibrils or assemblies of microfibrils, which straighten out and become more regularly aligned with strain. Previous and current X-ray diffraction results consistently show a partial ordering of microfibrils in zonular filaments into staggered aggregates which become more ordered and laterally aligned on stretching. Although the removal and re-addition of Ca(2+) is known to change the molecular structure of fibrillin, no effect was observed on the tensile properties of the zonular filaments. It is hypothesised that strain-induced deformation in the supramolecular aggregate packing may not be Ca(2+)-sensitive but could dominate the mechanical behaviour of microfibrillar arrays in zonular filaments.
The supramolecular organisation of fibrillin-rich microfibrils determines the mechanical properties of bovine zonular filaments
- Views Icon Views
- PDF LinkPDF
- Share Icon Share
- Search Site
D.M. Wright, V.C. Duance, T.J. Wess, C.M. Kielty, P.P. Purslow; The supramolecular organisation of fibrillin-rich microfibrils determines the mechanical properties of bovine zonular filaments. J Exp Biol 1 November 1999; 202 (21): 3011–3020. doi: https://doi.org/10.1242/jeb.202.21.3011
Download citation file: