BeStSel: analysis site for protein CD spectra-2025 update.

Circular dichroism (CD) spectroscopy is a widely used technique to characterize the secondary structure composition of proteins. We have developed the Beta Structure Selection (BeStSel) method (PNAS, 112, E3095), which solves the main problem of protein CD spectroscopy-namely, the spectral variability of β-structures. The BeStSel web server utilizes this method to provide tools to the community for CD spectrum analysis.

Probing the colloidal behavior of a cell wall polysaccharides-degrading enzyme in a highly constrained model system.

Understanding the specific interaction of cell wall polysaccharides degrading-enzymes with their substrates is of fundamental and practical interest for the fine grasp of their activity. Such interactions are difficult to unveil in real-life conditions due to the structural complexity of the plant cell wall. In this work, we present complex and highly confined model systems of cholesteric cellulose nanocrystal suspensions reaching dimensions close to those found in the plant cell wall.

Proof of concept study on differentiating metastatic brain samples by their originating organ using multimodal autofluorescence spectroscopy.

Brain metastasis are the most frequent central nervous system tumors that usually occur during systemic malignancy. However, they can be diagnosed before the primary cancer site. The number of brain and systemic metastases and the identification of the primary cancer can favor specific treatments and impacts survival estimates.

Guide to the structural characterization of protein aggregates and amyloid fibrils by CD spectroscopy.

Protein aggregation and amyloid formation are linked to numerous degenerative diseases, such as Alzheimer's or Parkinson's disease. Additionally, protein aggregation plays a crucial role in various biological processes, such as storage of molecules or cell signaling. Protein molecules can form a wide range of aggregates, from oligomers of different sizes to non-specific aggregates and highly ordered cross-β structured amyloid fibrils with diverse morphologies.

Change in muscle fibre protein structure following salting process assessed by synchrotron deep UV fluorescence microspectroscopy.

Samples of pork teres major muscle were salted and tumbled with 0.9 %, 1.3 % & 1.

Intracellular Quantification of an Antibiotic Metal Complex in Single Cells of Using Cryo-X-ray Fluorescence Nanoimaging.

Bacterial resistance is a major public health challenge. In Gram-negative bacteria, the synergy between multidrug efflux pumps and outer membrane impermeability determines the intracellular concentration of antibiotics. Consequently, it also dictates antibiotic activity on their respective targets.

Comparison of kink-band structures and specificities of cell wall polysaccharides in modern and ancient flax fibres.

Flax (Linum usitatissimum L.) is a plant of industrial importance, its fibres being presently used for high-value textile applications, composite reinforcements as well as natural actuators. Human interest in this fibre-rich plant dates back several millennia, including to Ancient Egypt where flax was used extensively in various quotidian items.

Influence of pH and lipid membrane on the liquid-liquid phase separation of wheat γ-gliadin in aqueous conditions.

Protein body (PB) formation in wheat seeds is a critical process influencing seed content and nutritional quality. In this study, we investigate the potential mechanisms governing PB formation through an in vitro approach, focusing on γ-gliadin, a key wheat storage protein. We used a microfluidic technique to encapsulate γ-gliadin within giant unilamellar vesicles (GUVs) and tune the physicochemical conditions in a controlled and rapid way.

Specific and label-free endogenous signature of dystrophic muscle by Synchrotron deep ultraviolet radiation.

Dystrophic muscle is characterized by necrosis/regeneration cycles, inflammation, and fibro-adipogenic development. Conventional histological stainings provide essential topographical data of this remodeling but may be limited to discriminate closely related pathophysiological contexts. They fail to mention microarchitecture changes linked to the nature and spatial distribution of tissue compartment components.

Interactions between proteins and cellulose in a liquid crystalline media: Design of a droplet based experimental platform.

Model systems are needed to provide controlled environment for the understanding of complex phenomena. Interaction between polysaccharides and proteins in dense medium are involved in numerous complex systems such as biomass conversion or plant use for food processing or biobased materials. In this work, cellulose nanocrystals (CNCs) were used to study proteins in a dense and organized cellulosic environment.

Role of the Protein Corona in the Colloidal Behavior of Microplastics.

Microparticles of polyethylene and polypropylene are largely found in aquatic environments because they are the most produced and persistent plastic materials. Once in biological media, they are covered by a layer of molecules, the so-called corona, mostly composed of proteins. A yeast protein extract from was used as a protein system to observe interactions in complex biological media.

Evolution of the ultrastructure and polysaccharide composition of flax fibres over time: When history meets science.

Flax fibres have been used by humans for approximately 10,000 years. With time, the geographic area of production and cultivation has changed, as have the applications of flax fibres; from clothing to sails and paintings from antiquity, to automotive, fashion, and design applications in the contemporary era. The degradation process of flax fibres is the same for both ancient and modern objects made from this polysaccharidic material.

Label-free 3D characterization of cardiac fibrosis in muscular dystrophy using SHG imaging of cleared tissue.

Background Information: Duchenne muscular dystrophy (DMD) is a neuromuscular disease caused by mutations in the gene encoding dystrophin. It leads to repeated cycles of muscle fiber necrosis and regeneration and progressive replacement of fibers by fibrotic and adipose tissue, with consequent muscle weakness and premature death. Fibrosis and, in particular, collagen accumulation are important pathological features of dystrophic muscle.

Lessons on textile history and fibre durability from a 4,000-year-old Egyptian flax yarn.

Flax has a long and fascinating history. This plant was domesticated around 8,000 BCE in the Fertile Crescent area, first for its seeds and then for its fibres. Although its uses existed long before domestication, residues of flax yarn dated 30,000 years ago have been found in the Caucasus area.

Investigations by AFM of Ageing Mechanisms in PLA-Flax Fibre Composites during Garden Composting.

PLA-flax non-woven composites are promising materials, coupling high performance and possible degradation at their end of life. To explore their ageing mechanisms during garden composting, microstructural investigations were carried out through scanning electron microscopy (SEM) and atomic force microscopy (AFM). We observe that flax fibres preferentially degrade 'inwards' from the edge to the core of the composite.

PB1-F2 amyloid-like fibers correlate with proinflammatory signaling and respiratory distress in influenza-infected mice.

PB1-F2 is a virulence factor of influenza A virus known to increase viral pathogenicity in mammalian hosts. PB1-F2 is an intrinsically disordered protein displaying a propensity to form amyloid-like fibers. However, the correlation between PB1-F2 structures and the resulting inflammatory response is unknown.

The endosperm cavity of wheat grains contains a highly hydrated gel of arabinoxylan.

Cereal grains provide a substantial part of the calories for humans and animals. The main quality determinants of grains are polysaccharides (mainly starch but also dietary fibers such as arabinoxylans, mixed-linkage glucans) and proteins synthesized and accumulated during grain development in a specialized storage tissue: the endosperm. In this study, the composition of a structure localized at the interface of the vascular tissues of the maternal plant and the seed endosperm was investigated.

Molecular changes tracking through multiscale fluorescence microscopy differentiate Meningioma grades and non-tumoral brain tissues.

Meningioma is the most common primary intracranial extra-axial tumor. Total surgical removal is the standard therapeutic method to treat this type of brain tumors. However, the risk of recurrence depends on the tumor grade and the extent of the resection including the infiltrated dura mater and, if necessary, the infiltrated bone.

FTIR micro-spectroscopy using synchrotron-based and thermal source-based radiation for probing live bacteria.

Fourier transform infrared (FTIR) spectroscopy has proven to be a non-invasive tool to analyse cells without the hurdle of employing exogenous dyes or probes. Nevertheless, the study of single live bacteria in their aqueous environment has long remained a big challenge, due to the strong infrared absorption of water and the small size of bacteria compared to the micron-range infrared wavelengths of the probing photons. To record infrared spectra of bacteria in an aqueous environment, at different spatial resolutions, two setups were developed.

Synchrotron multimodal imaging in a whole cell reveals lipid droplet core organization.

A lipid droplet (LD) core of a cell consists mainly of neutral lipids, triacylglycerols and/or steryl esters (SEs). The structuration of these lipids inside the core is still under debate. Lipid segregation inside LDs has been observed but is sometimes suggested to be an artefact of LD isolation and chemical fixation.

The shell matrix of the european thorny oyster, Spondylus gaederopus: microstructural and molecular characterization.

Molluscs, the largest marine phylum, display extraordinary shell diversity and sophisticated biomineral architectures. However, mineral-associated biomolecules involved in biomineralization are still poorly characterised. We report the first comprehensive structural and biomolecular study of Spondylus gaederopus, a pectinoid bivalve with a peculiar shell texture.

Time resolved transient circular dichroism spectroscopy using synchrotron natural polarization.

Ultraviolet (UV) synchrotron radiation circular dichroism (SRCD) spectroscopy has made an important contribution to the determination and understanding of the structure of bio-molecules. In this paper, we report an innovative approach that we term time-resolved SRCD (tr-SRCD), which overcomes the limitations of current broadband UV SRCD setups. This technique allows accessing ultrafast time scales (down to nanoseconds), previously measurable only by other methods, such as infrared (IR), nuclear magnetic resonance (NMR), fluorescence and absorbance spectroscopies, and small angle X-ray scattering (SAXS).

Mobility of pectin methylesterase in pectin/cellulose gels is enhanced by the presence of cellulose and by its catalytic capacity.

The pectin methylesterase action is usually studied in a homogeneous aqueous medium in the presence of a large excess of soluble substrate and water. However in the cell wall, the water content is much lower, the substrate is cross-linked with itself or with other polymers, and the enzyme has to diffuse through the solid matrix before catalysing the linkage breakdown. As plant primary cell walls can be considered as cellulose-reinforced hydrogels, this study investigated the diffusion of a fungal pectin methylesterase in pectin/cellulose gels used as cell wall-mimicking matrix to understand the impact of this matrix and its (micro) structure on the enzyme's diffusion within it.

Optical Signatures Derived From Deep UV to NIR Excitation Discriminates Healthy Samples From Low and High Grades Glioma.

Among all the tumors of the central nervous system (CNS), glioma are the most deadly and the most malignant. Surgical resection is the standard therapeutic method to treat this type of brain cancer. But the diffusive character of these tumors create many problems for surgeons during the operation.