The Physiological and Pathological Implications of the Formation of Hydrogels, with a Specific Focus on Amyloid Polypeptides.

Hydrogels are water-swollen and viscoelastic three-dimensional cross-linked polymeric network originating from monomer polymerisation. Hydrogel-forming polypeptides are widely found in nature and, at a cellular and organismal level, they provide a wide range of functions for the organism making them. Amyloid structures, arising from polypeptide aggregation, can be damaging or beneficial to different types of organisms.

Rapid method for measurement of surface tension in multiwell plates.

We describe an optical method for quantifying surface tension in 96-well microtitre plates. Absorbance and fluorescence measurements in vertical beam systems as in 96-well plate photometers are complicated by the interaction of the light with the curved surface of the liquid. If the samples do not all have the same meniscus, errors in the data proportional to the degree of curvature are produced, which may confound interpretation of the data.

The intact human acetylcholinesterase C-terminal oligomerization domain is alpha-helical in situ and in isolation, but a shorter fragment forms beta-sheet-rich amyloid fibrils and protofibrillar oligomers.

A 14-residue fragment of the C-terminal oligomerization domain, or T-peptide, of human acetylcholinesterase (AChE) shares sequence homology with the amyloid-beta peptide implicated in Alzheimer's disease and can spontaneously self-assemble into classical amyloid fibrils under physiological conditions [Greenfield, S. A., and Vaux, D.

Amyloid fibril formation by a synthetic peptide from a region of human acetylcholinesterase that is homologous to the Alzheimer's amyloid-beta peptide.

A region near the C-terminus of human acetylcholinesterase (AChE) is weakly homologous with the N-terminus of the Alzheimer's disease amyloid-beta peptide. We report that a 14-amino acid synthetic polypeptide whose sequence corresponds to residues 586-599 of the human synaptic or T form of AChE assembles into amyloid fibrils under physiological conditions. The fibrils have all the classical characteristics of amyloid: they have a diameter of 6-7 nm and bind both Congo red and thioflavin-T.