Search results for "Note"

Nautilin-63, a novel acidic glycoprotein from the shell nacre of Nautilus macromphalus

2011

In molluscs, and more generally in metazoan organisms, the production of a calcified skeleton is a complex molecular process that is regulated by the secretion of an extracellular organic matrix. This matrix constitutes a cohesive and functional macromolecular assemblage, containing mainly proteins, glycoproteins and polysaccharides that, together, control the biomineral formation. These macromolecules interact with the extruded precursor mineral ions, mainly calcium and bicarbonate, to form complex organo-mineral composites of well-defined microstructures. For several reasons related to its remarkable mechanical properties and to its high value in jewelry, nacre is by far the most studied …

Introduction: Protein Oligomerization and the Formation of Macromolecular Assemblies

2019

The ability of biomolecules to link together to form higher order assemblies underlies much of cellular structure and function. Here we emphasise protein oligomerisation and discuss some of the principles of molecular interaction, from early considerations through to the present day. A few protein examples are presented, selected from our research interests, to highlight assembly features, ranging from the hemoglobins, the hemocyanins to the peroxiredoxins, collagen, the encapsulins and ferritins.

Spatial Demixing of Ring and Chain Polymers in Pressure-Driven Flow

2019

We investigate mixtures of ring and linear polymers in solution at various number ratios, ranging from pure chains to pure rings, and at densities around the overlap concentration. In bulk and at r...

Polylactic acid, a sustainable, biocompatible, transparent substrate material for Organ-On-Chip, and Microfluidic applications

2019

AbstractOrgan-on-chips are miniaturised devices aiming at replacing animal models for drug discovery, toxicology and studies of complex biological phenomena. The field of Organ-On-Chip has grown exponentially, and has led to the formation of companies providing commercial Organ-On-Chip devices. Yet, it may be surprising to learn that the majority of these commercial devices are made from Polydimethylsiloxane (PDMS), a silicone elastomer that is widely used in microfluidic prototyping, but which has been proven difficult to use in industrial settings and poses a number of challenges to experimentalists, including leaching of uncured oligomers and uncontrolled adsorption of small compounds. T…

The Role of Enzymes in Biomineralization Processes

2010

Formation of Aroma by Hydrolysis of Glycosidically Bound Components

1992

SUMMARY Acid hydrolysis has been used in order to establish the presence of glycosidically bound components in fruits. During this treatment, rearrangement reactions of free monoterpene alcohols generally occur. This inconvenient may be avoided using enzymatic hydrolysis, however the specificity of enzymes requires the previous knowledge of the structures of compounds used as substrates in order to control the reaction. Several glycosidically bound components, glucosides, rutinosides and arabinoglucosides present in grapes and apricot were isolated, separated and identified using non destructive methods, MS-MS low energy CAD spectra and HPLC. s-D-glucosidase, α-L-rhamnosidase, α-L-arabinase…

Biologically-induced transition of bio-silica sol to mesoscopic gelatinous flocs: a biomimetic approach to a controlled fabrication of bio-silica str…

2012

Siliceous sponges form their skeletal elements, the spicules, enzymatically via the sponge-specific enzyme silicatein. The enzymatic product of silicatein in vitro is a bio-silica polymer that is not processed/hardened by phase separation. In the present study we applied a two-phase system to investigate the transition of bio-silica, formed by silicatein, from the lucid state to the opaque/turbid state. We report for the first time that the polyether polyethylene glycol [PEG] causes a rapid transition of the lucid bio-silica to the opaque/turbid state. For the experiments the recombinant silicatein from the demosponge Suberites domuncula had been used. This process is rapid (1 h) and procee…

Silintaphin-1 - interaction with silicatein during structure-guiding bio-silica formation

2011

Silicateins are unique enzymes of sponges (phylum Porifera) that template and catalyze the polymerization of nanoscale silicate to siliceous skeletal elements. These multifunctional spicules are often elaborately shaped, with complex symmetries. They carry an axial proteinaceous filament, consisting of silicatein and the scaffold protein silintaphin-1, which guides silica deposition and subsequent spicular morphogenesis. In vivo, the synthesis of the axial filament very likely proceeds in three steps: (a) assembly of silicatein monomers to form one pentamer; (b) assembly of pentamers to form fractal-like structures; and finally (c) assembly of fractal-like structures to form filaments. The …

Polymers with antiviral properties: A brief review.

2021

Viruses that are pathogenic to humans and livestock pose a serious epidemiological threat and challenge the world's population. The SARS-CoV-2/COVID-19 pandemic has made the world aware of the scale of the threat. The surfaces of various materials can be a source of viruses that remain temporarily contagious in the environment. Few polymers have antiviral effects that reduce infectivity or the presence of a virus in the human environment. Some of the effects are due to certain physical properties, e.g., high hydrophobicity. Other materials owe their antiviral activity to a modified physicochemical structure favoring the action on specific virus receptors or on their biochemistry. Current re…

Thioflavin T Promotes Aβ(1−40) Amyloid Fibrils Formation

2015

Fibrillogenesis of the small peptide Aβ(1-40) is considered to be the hallmark of Alzheimer's disease. Some evidence indicates small oligomers, rather than mature fibrils, as the key cytotoxic agents. The fluorescent dye Thioflavin T (ThT) is often used to detect amyloid deposits in both in vivo and in vitro experiments, and it is used to study kinetic measurements, under the fundamental hypothesis that this probe does not influence the aggregation processes. We report experimental data showing that ThT may promote the Aβ(1-40) peptide amyloid aggregation changing solvent-peptide interactions and stabilizing more ordered β-like conformation. This finding has a two-fold importance: It is a f…