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Full-Text Articles in Physical Sciences and Mathematics

Monotremes Provide A Key To Understanding The Evolutionary Significance Of Epididymal Sperm Maturation, Brett Nixon, Russell Jones, Jean-Louis Dacheux, Heath Ecroyd Dec 2012

Monotremes Provide A Key To Understanding The Evolutionary Significance Of Epididymal Sperm Maturation, Brett Nixon, Russell Jones, Jean-Louis Dacheux, Heath Ecroyd

Heath Ecroyd

"It has been widely accepted that mammalian spermatozoa are infertile when they leave the testes and require a period of maturation in both the epididymis and the female reproductive tract before acquiring the ability to fertilize an oocyte. However, the necessity for such a complex process of posttesticular sperm maturation appears to be unique to mammals because it is well established that these processes do not directly influence the fertilizing ability of the spermatozoa of birds, reptiles, and other lower vertebrates. Because of their key evolutionary position and form of reproduction, we contend that monotremes (platypus and echidna) provide a …


Nmr Spectroscopy Of 14-3-3zeta Reveals A Flexible C-Terminal Extension: Differentiation Of The Chaperone And Phosphoserine-Binding Activities Of 14-3-3zeta, H Fu, Danielle Williams, Heath Ecroyd, John Carver, Lixin Zhang, Huanqin Dai, Joanna Woodcock, K Goodwin Dec 2012

Nmr Spectroscopy Of 14-3-3zeta Reveals A Flexible C-Terminal Extension: Differentiation Of The Chaperone And Phosphoserine-Binding Activities Of 14-3-3zeta, H Fu, Danielle Williams, Heath Ecroyd, John Carver, Lixin Zhang, Huanqin Dai, Joanna Woodcock, K Goodwin

Heath Ecroyd

Intracellular 14-3-3 proteins bind to many proteins, via a specific phosphoserine motif, regulating diverse cellular tasks including cell signalling and disease progression. The 14-3-3 isoform is a molecular chaperone, preventing the stressinduced aggregation of target proteins in a manner comparable with that of the unrelated sHsps (small heat-shock proteins). 1H-NMR spectroscopy revealed the presence of a flexible and unstructured C-terminal extension, 12 amino acids in length, which protrudes from the domain core of 14-3-3 and is similar in structure and length to the C-terminal extension of mammalian sHsps. The extension stabilizes 14-3-3, but has no direct role in chaperone action. …


Enhanced Molecular Chaperone Activity Of The Small Heat-Shock Protein Alphab-Cystallin Following Covalent Immobilization Onto A Solid-Phase Support, V Bellotti, Heath Ecroyd, J Carver, H J Griesser, B Thierry, J G Shapter, S S Griesser, S Giorgetti, M R Nussio, J A Gerrard, J Garvey Dec 2012

Enhanced Molecular Chaperone Activity Of The Small Heat-Shock Protein Alphab-Cystallin Following Covalent Immobilization Onto A Solid-Phase Support, V Bellotti, Heath Ecroyd, J Carver, H J Griesser, B Thierry, J G Shapter, S S Griesser, S Giorgetti, M R Nussio, J A Gerrard, J Garvey

Heath Ecroyd

The well-characterized small heat-shock protein, alphaB-crystallin, acts as a molecular chaperone by interacting with unfolding proteins to prevent their aggregation and precipitation. Structural perturbation (e.g., partial unfolding) enhances the in vitro chaperone activity of alphaB-crystallin. Proteins often undergo structural perturbations at the surface of a synthetic material, which may alter their biological activity. This study investigated the activity of alphaB-crystallin when covalently bound to a support surface; alphaB-crystallin was immobilized onto a range of solid material surfaces, and its characteristics and chaperone activity were assessed. Immobilization was achieved via a plasma-deposited thin polymeric interlayer containing aldehyde surface groups and reductive …


Amyloid Fibril Formation By Bovine Milk Alpha(S2)-Casein Occurs Under Physiological Conditions Yet Is Prevented By Its Natural Counterpart, Alpha(S1)-Casein, David Thorn, Heath Ecroyd, M Sunde, Stephen Poon, John Carver Dec 2011

Amyloid Fibril Formation By Bovine Milk Alpha(S2)-Casein Occurs Under Physiological Conditions Yet Is Prevented By Its Natural Counterpart, Alpha(S1)-Casein, David Thorn, Heath Ecroyd, M Sunde, Stephen Poon, John Carver

Heath Ecroyd

The calcified proteinaceous deposits, or corpora amylacea, of bovine mammary tissue often comprise a network of amyloid fibrils, the origins of which have not been fully elucidated. Here, we demonstrate by transmission electron microscopy, dye binding assays, and X-ray fiber diffraction that bovine milk alpha(s2)-casein, a protein synthesized and secreted by mammary epithelial cells, readily forms fibrils in vitro. As a component of whole alpha(s)-casein, alpha(s2)-casein was separated from alpha(s1)-casein under nonreducing conditions via cation-exchange chromatography. Upon incubation at neutral pH and 37 degrees C, the spherical particles typical of alpha(s2)-casein rapidly converted to twisted, ribbon-like fibrils similar to 12 …


Protective Interactions Of Dairy Peptides With Fibril Structures And Relevance To Alzheimer's Disease, Louise Bennett, Williams Roderick, Heath Ecroyd, Yanqin Liu, Sunanda Sudharmarajan, John Carver Dec 2011

Protective Interactions Of Dairy Peptides With Fibril Structures And Relevance To Alzheimer's Disease, Louise Bennett, Williams Roderick, Heath Ecroyd, Yanqin Liu, Sunanda Sudharmarajan, John Carver

Heath Ecroyd

Selected dairy caseins have been shown to have capacity for chaperone-like regulation of folding pathways of other caseins, specifically in preventing development of fibrillar aggregates of beta sheet structure. An assay based on fibril formation by reduced and carboxymethylated-kappa casein (RCM-kCn) was thus used to screen for anti-fibril activity among a selection of dairy protein hydrolysates, in order to discover peptides with possible anti-fibril, chaperone activity. From the selection of eight dairy hydrolysates based on different dairy protein fractions, two of the hydrolysates of whey protein exhibited superior anti-fibril bioactivity against RCM-kCn and amyloid beta (Aβ), the peptide associated with …