Building an Artificial Plant Cell Wall on a Lipid Bilayer by Assembling Polysaccharides and Engineered Proteins.

The cell wall constitutes a fundamental structural component of plant cells, providing them with mechanical resistance and flexibility. Mimicking this wall is a critical step in the conception of an experimental model of the plant cell. The assembly of cellulose/hemicellulose in the form of cellulose nanocrystals and xyloglucans as a representative model of the plant cell wall has already been mastered; however, these models lacked the pectin component.

Biophysical analysis of the plant-specific GIPC sphingolipids reveals multiple modes of membrane regulation.

The plant plasma membrane (PM) is an essential barrier between the cell and the external environment, controlling signal perception and transmission. It consists of an asymmetrical lipid bilayer made up of three different lipid classes: sphingolipids, sterols, and phospholipids. The glycosyl inositol phosphoryl ceramides (GIPCs), representing up to 40% of total sphingolipids, are assumed to be almost exclusively in the outer leaflet of the PM.

Deposition of Cellulose Nanocrystals onto Supported Lipid Membranes.

The deposition of cellulose nanocrystals (CNCs) on a supported lipid bilayer (SLB) was investigated at different length scales. Quartz crystal microbalance with dissipation monitoring (QCM-D) was used to probe the bilayer formation and to show for the first time the CNC deposition onto the SLB. Specifically, classical QCM-D measurements gave estimation of the adsorbed hydrated mass and the corresponding film thickness, whereas complementary experiments using DO as the solvent allowed the quantitative determination of the hydration of the CNC layer, showing a high hydration value.

The dual role of MamB in magnetosome membrane assembly and magnetite biomineralization.

Magnetospirillum gryphiswaldense MSR-1 synthesizes membrane-enclosed magnetite (Fe O ) nanoparticles, magnetosomes, for magnetotaxis. Formation of these organelles involves a complex process comprising key steps which are governed by specific magnetosome-associated proteins. MamB, a cation diffusion facilitator (CDF) family member has been implicated in magnetosome-directed iron transport.

pH-Sensitive Interactions between Cellulose Nanocrystals and DOPC Liposomes.

The interaction of 1,2 dioleolyl-sn-glycero-3-phosphatidylcholine (DOPC) vesicles with cellulose nanocrystals (CNCs) using several complementary techniques. Dynamic light scattering, zeta-potential, cryo-transmission electron microscopy and isothermal titration calorimetry (ITC) analyses confirmed the formation of pH-dependent CNC-liposome complexes. ITC was used to characterize the thermodynamic properties of this interaction.

Disease-Homologous Mutation in the Cation Diffusion Facilitator Protein MamM Causes Single-Domain Structural Loss and Signifies Its Importance.

Cation diffusion facilitators (CDF) are highly conserved, metal ion efflux transporters that maintain divalent transition metal cation homeostasis. Most CDF proteins contain two domains, the cation transporting transmembrane domain and the regulatory cytoplasmic C-terminal domain (CTD). MamM is a magnetosome-associated CDF protein essential for the biomineralization of magnetic iron-oxide particles in magnetotactic bacteria.

Dendritic Elastin-like Peptides: The Effect of Branching on Thermoresponsiveness.

Elastin-like peptides (ELPs) have been used widely to confer thermoresponsive characteristics onto various materials, but to this point mostly linear ELPs have been studied. A class of linear and dendritic (branched) ELPs based on the GLPGL pentamer repeat unit was synthesized using an on-resin divergent strategy. The effect of peptide topology on the transition temperature (Tt) was examined using circular dichroism to study the peptide secondary structure transition and turbidity to measure the macroscopic phase transition (coacervation).

Thermal properties of ruthenium alkylidene-polymerized dicyclopentadiene.

Differential scanning calorimetry (DSC) analysis of ring opening methatesis polymerization (ROMP) derived polydicyclopentadiene (PDCPD) revealed an unexpected thermal behavior. A recurring exothermic signal can be observed in the DSC analysis after an elapsed time period. This exothermic signal was found to be proportional to the resting period and was accompanied by a constant increase in the glass-transition temperature.

Light-Controlled Hierarchical Self-Assembly of Polyelectrolytes and Supramolecular Polymers.

Dynamic control over supramolecular interactions using various stimuli continues to drive the development of smart materials. We describe here the extension of dynamic self-assembly to a self-assembled hierarchical structure. A peptide amphiphile (PA) was designed with a photocleavable nitrobenzyl ester component such that it would undergo a sphere-to-cylinder transition upon irradiation, as confirmed by cryogenic transmission electron microscopy and small-angle X-ray scattering (SAXS).