Assembly of Poly(vinylphosphonic acid)-Based Double Hydrophilic Block Copolymers by Gadolinium Ions for the Formation of Highly Stable MRI Contrast Agents.

Mixing double-hydrophilic block copolymers containing a poly(vinylphosphonic acid) block with gadolinium ions in water leads to the spontaneous formation of polymeric nanoparticles. With an average diameter near 20 nm, the nanoparticles are stable after dilution or change of pH and ionic strength. High magnetic relaxivities were measured in vitro, and in vivo magnetic resonance imaging on rats demonstrates the high potential of such polymeric assemblies.

The molecular basis of polysaccharide cleavage by lytic polysaccharide monooxygenases.

Lytic polysaccharide monooxygenases (LPMOs) are copper-containing enzymes that oxidatively break down recalcitrant polysaccharides such as cellulose and chitin. Since their discovery, LPMOs have become integral factors in the industrial utilization of biomass, especially in the sustainable generation of cellulosic bioethanol. We report here a structural determination of an LPMO-oligosaccharide complex, yielding detailed insights into the mechanism of action of these enzymes.

Quantification of nanoparticle endocytosis based on double fluorescent pH-sensitive nanoparticles.

Amorphous silica is a particularly interesting material because of its inertness and chemical stability. Silica nanoparticles have been recently developed for biomedical purposes but their innocuousness must be carefully investigated before clinical use. The relationship between nanoparticles physicochemical features, their uptake by cells and their biological activity represents a crucial issue, especially for the development of nanomedicine.

Lipo-chitin oligosaccharides, plant symbiosis signalling molecules that modulate mammalian angiogenesis in vitro.

Lipochitin oligosaccharides (LCOs) are signaling molecules required by ecologically and agronomically important bacteria and fungi to establish symbioses with diverse land plants. In plants, oligo-chitins and LCOs can differentially interact with different lysin motif (LysM) receptors and affect innate immunity responses or symbiosis-related pathways. In animals, oligo-chitins also induce innate immunity and other physiological responses but LCO recognition has not been demonstrated.

Access to tetra-N-acetyl-chitopentaose by chemical N-acetylation of glucosamine pentamer.

Nowadays, the easy access of tetra-N-acetyl-chitopentaose and its counterparts is highly interesting since such chemical compounds are precursors of biological signal molecules with a strong agro-economic impact. The chemical synthesis of tetra-N-acetyl-chitopentaose by controlled N-acetylation of the glucosamine pentamer hydrochloride under mild conditions is described herein. A systematic study on the influence of the different parameters involved in this reaction, such as the solvent, the acetylating agent, and the base used for the deprotonation of ammonium groups of the starting material was carried out.

Biodistribution study of nanometric hybrid gadolinium oxide particles as a multimodal SPECT/MR/optical imaging and theragnostic agent.

Nanometric hybrid gadolinium oxide particles (Gado-6Si-NP) for diagnostic and therapeutic applications (mean diameter 3-4 nm) were obtained by encapsulating Gd(2)O(3) cores within a polysiloxane shell, which carries organic fluorophore (Cy 5) and is derivatized by a hydrophilic carboxylic layer. As residency time in the living body and methods of waste elimination are crucial to defining a good nanoparticle candidate and moving forward with steps for validation, this study was aimed at evaluating the biodistribution of these multimodal Gado-6Si-NP in rodents. Gado-6Si-NP were imaged following intravenous injection in control Wistar rats and mice using MRI (7 T), optical fluorescent imaging, and SPECT.

New chromogenic substrates for feruloyl esterases.

Indolyl and nitrophenyl 5-O-hydroxycinnamoyl-alpha-L-arabinofuranosides were prepared by chemo-enzymatic syntheses. These probes were designed as substrates to be used in assays of feruloyl esterase activity (EC 3.1.

Chromogenic substrates for feruloyl esterases.

Chromogenic mono- and diferuloyl-butanetriol analogs were prepared by chemical syntheses and their efficiency was evaluated as substrates for feruloyl esterases from Aspergillus niger.

Synthesis of triazole-linked pseudo-starch fragments.

Rapid assembly of starch fragment analogues was achieved using 'click chemistry'. Specifically, a pentadecasaccharide and two hexadecasaccharide mimics containing two parallel maltoheptaosyl chains linked via [1,2,3]-triazoles to glucose or maltose core were synthesised using Cu(I)-catalyzed [3+2] dipolar cycloaddition of azidosaccharides and 4,6-di-O-propargylated methyl alpha-d-glucopyranoside and 6,6'- and 4',6'-di-O-propargylated p-methoxyphenyl beta-maltoside.

Respective importance of protein folding and glycosylation in the thermal stability of recombinant feruloyl esterase A.

The thermal stability of four molecular forms (native, refolded, glycosylated, non-glycosylated) of feruloyl esterase A (FAEA) was studied. From the most to the least thermo-resistant, the four molecular species ranked as follows: (i) glycosylated form produced native, (ii) non-glycosylated form produced native, (iii) non-glycosylated form produced as inclusion bodies and refolded, and (iv) glycosylated form produced native chemically denatured and then refolded. On the basis of these results and of crystal structure data, we discuss the respective importance of protein folding and glycosylation in the thermal stability of recombinant FAEA.

"Click chemistry"en route to pseudo-starch.

Rapid assembly of starch fragment analogues was achieved using "click chemistry". Specifically, two hexadecasaccharide mimics containing two parallel maltoheptaosyl chains linked via [1,2,3]-triazoles to a maltose core were synthesized using Cu(i)-catalyzed [3 + 2] dipolar cycloaddition of azido saccharides and 6,6'- and 4',6'-dipropargylated p-methoxyphenyl maltoside.