Catalytic activity of CuO nanoparticles supported on cellulose beads prepared by emulsion-gelation using cellulose/LiBr solution and vegetable oil.

Nanocatalysts tend to aggregate and are difficult to recycle, limiting their practical applications. In this study, an environmentally friendly method was developed to produce cellulose beads for use as supporting materials for Cu-based nanocatalysts. Cellulose beads were synthesized from a water-in-oil emulsion using cellulose dissolved in an LiBr solution as the water phase and vegetable oil as the oil phase.

Elucidation of the Specific Ion Effects and Intermediate Structures of Cellulose Fibers Swollen in Inorganic Salt Solutions via In Situ X-ray Diffraction.

The solubilities of many substances are significantly affected by specific ions, as demonstrated by the Hofmeister series of proteins. Cellulose has a resistant fibrillar structure that hinders its swelling and dissolution. Certain inorganic salt solutions are effective swelling agents and solvents for cellulose.

α-d-(1 → 3)-graft-(1 → 6)-glucan: Comb-like polysaccharide synthesized in vitro with α-1,3/1,6-glucosyltransferase L from Streptococcus salivarius.

We demonstrated that a unique polysaccharide with extremely high molecular weight can be easily obtained via a low-cost, mild reaction in a water medium from sucrose, a photosynthetic product. α-1,3/1,6-Glucosyltransferase L (GtfL) from Streptococcus salivarius produced water-insoluble α-d-glucan from sucrose at 37 °C. Gel permeation chromatography revealed the molecular weight was extremely high; the weight-average molecular weight values were more than 1,000,000 irrespective of the substrate concentration.

Triplet-DNP in magnetically oriented microcrystal arrays.

We explore dynamic nuclear polarization using electron spins in the photo-excited triplet state (Triplet-DNP) in magnetically oriented microcrystal arrays (MOMAs) of pentacene-doped p-terphenyl, in which the individual crystallites are magnetically aligned and UV-cured. In contrast to the conventional approach to Triplet-DNP in powder, which suffers from reduced nuclear polarization due to the averaged electron polarization and the broadening of electron-spin resonance, Triplet-DNP of the MOMAs offers as high dynamic polarization as that attainable in single-crystals. In the case of pentacene-doped p-terphenyl, the enhanced H polarization in the one-dimensional MOMA, prepared simply by leaving the suspension in a stationary magnetic field before UV curation, can be higher than that attainable in the powder sample by an order of magnitude and comparable to that in single crystals and in the three-dimensional MOMA made using a modulational rotating field.

Lignocellulose molecular assembly and deconstruction properties of lignin-altered rice mutants.

Bioengineering approaches to modify lignin content and structure in plant cell walls have shown promise for facilitating biochemical conversions of lignocellulosic biomass into valuable chemicals. Despite numerous research efforts, however, the effect of altered lignin chemistry on the supramolecular assembly of lignocellulose and consequently its deconstruction in lignin-modified transgenic and mutant plants is not fully understood. In this study, we aimed to close this gap by analyzing lignin-modified rice (Oryza sativa L.

Synthesis of Branchless Linear (1 → 6)-α-d-Glucan by Glucosyltransferase K: Mechanical and Swelling Properties of Its Hydrogels Crosslinked with Diglycidyl Ethers.

A hydrogel was prepared from a polysaccharide, enzymatically synthesized through a one-pot reaction in aqueous solution, and its properties as a functional material were evaluated. Enzymatic synthesis using glucosyltransferase K obtained from ATCC 25975 was performed with sucrose as a substrate. The synthetic product was unbranched linear (1 → 6)-α-d-glucan with a high molecular weight, : 1.

Loss of the cystine/glutamate antiporter in melanoma abrogates tumor metastasis and markedly increases survival rates of mice.

The cystine/glutamate antiporter, system x , is essential for the efficient uptake of cystine into cells. Interest in the mechanisms of system x function soared with the recognition that system x presents the most upstream node of ferroptosis, a recently described form of regulated necrosis relevant for degenerative diseases and cancer. Since targeting system x hold the great potential to efficiently combat tumor growth and metastasis of certain tumors, we disrupted the substrate-specific subunit of system x , xCT (SLC7A11) in the highly metastatic mouse B16F10 melanoma cell line and assessed the impact on tumor growth and metastasis.

Cationic hydrogels prepared from regioselectively azidated (1→3)-α-d-glucan via crosslinking and amination: Physical and adsorption properties.

Cationic hydrogels with amino groups were successfully prepared using (1→3)-α-d-glucan synthesized by glucosyltransferase J (GtfJ) cloned from Streptococcus salivarius through a three-step reaction: (i) Azido groups were regioselectively introduced at the C6 position of (1→3)-α-d-glucan by a bromination-azidation process (degree of substitution 0.94), (ii) Azido groups were partially crosslinked with 1,8-nonadiyne via a copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction, (iii) Azido groups that were unused for crosslinking were reduced to amino groups by sodium borohydride (NaBH). The introduction of amino groups was confirmed quantitatively and qualitatively by elemental, Fourier transform infrared (FT-IR), and nuclear magnetic resonance (NMR) analyses.

Highly swellable hydrogel of regioselectively aminated (1→3)-α-d-glucan crosslinked with ethylene glycol diglycidyl ether.

(1→3)-α-d-glucan synthesized by glucosyltransferase J (GtfJ) cloned from Streptococcus salivarius was regioselectively aminated as 6-amino-6-deoxy-(1→3)-α-d-glucan (aminoglucan) through three steps: bromination, azidation, and reduction. The degree of substitution of the amino group was determined by elemental analysis to be 0.97 and the molecular weight was 3.

Altered lignocellulose chemical structure and molecular assembly in CINNAMYL ALCOHOL DEHYDROGENASE-deficient rice.

Lignin is a complex phenylpropanoid polymer deposited in plant cell walls. Lignin has long been recognized as an important limiting factor for the polysaccharide-oriented biomass utilizations. To mitigate lignin-associated biomass recalcitrance, numerous mutants and transgenic plants that produce lignocellulose with reduced lignin contents and/or lignins with altered chemical structures have been produced and characterised.

In situ solid-state NMR of a magnetically oriented microcrystal suspension.

In situ solid-state NMR measurements of a magnetically oriented microcrystal suspension (MOMS) were demonstrated. Under modulated rotation of the static field, or equivalently, of the sample tube, randomly oriented microcrystals in a viscous liquid medium feel a torque arising from the anisotropic bulk susceptibility and eventually aligned in the same direction. In this way, a three-dimensional MOMS (3D-MOMS) was obtained.

Cystine/glutamate transporter, system x, is involved in nitric oxide production in mouse peritoneal macrophages.

The amino acid transport system x is important for maintaining intracellular glutathione levels and extracellular redox balance. The main component of system x, xCT, is strongly induced by various stimuli, including oxidative stress and bacterial lipopolysaccharides (LPS) in macrophages. In the present study, we investigated the production of nitric oxide by LPS-stimulated mouse peritoneal macrophages isolated from both xCT-deficient and wild-type mice.

The ferroptosis inducer erastin irreversibly inhibits system x- and synergizes with cisplatin to increase cisplatin's cytotoxicity in cancer cells.

System x was recently described as the most upstream node in a novel form of regulated necrotic cell death, called ferroptosis. In this context, the small molecule erastin was reported to target and inhibit system x, leading to cysteine starvation, glutathione depletion and consequently ferroptotic cell death. Although the inhibitory effect of erastin towards system x is well-documented, nothing is known about its mechanism of action.

Characterization of crystalline linear (1→3)-α-d-glucan synthesized in vitro.

We investigated the crystal structure and molecular arrangement of the linear (1→3)-α-d-glucan synthesized by glucosyltransferase GtfJ cloned from Streptococcus salivarius using sucrose as a substrate. The synthetic products had two morphologies: wavy fibril-like crystals as major and thin lamellae as minor products. Their structures were analyzed using electron microdiffraction, synchrotron X-ray powder diffraction, and solid-state C NMR spectroscopy.

Single-crystal NMR approach for determining chemical shift tensors from powder samples via magnetically oriented microcrystal arrays.

The single-crystal rotation technique was applied to magnetically oriented microcrystal arrays (MOMAs) of cellobiose (monoclinic) to determine the principal values and principal axes of the chemical shift tensors of C1 and C1' carbons. Rotations were performed about the magnetic χ1, χ2, and χ3 axes of MOMA, and the measurements were taken at six different orientations with respect to the applied magnetic field. Under these rotations, crowded peaks were reduced and the peaks for the C1 and C1' carbons were identified by comparing with simulation results.

Cellulose ester-graft-poly(epsilon-caprolactone): effects of copolymer composition and intercomponent miscibility on the enzymatic hydrolysis behavior.

Enzymatic hydrolysis was conducted with Pseudomonas lipase for film samples of graft copolymers of cellulose acetate (CA) and butyrate (CB) with poly(epsilon-caprolactone) (PCL), CA-g-PCL, and CB-g-PCL, respectively. The two trunk polymers CA and CB, both having the degree of acyl substitution (DS) of >2, are respectively immiscible and miscible with PCL. A hindrance effect of the cellulose ester trunks on the enzymatic attack to the PCL component was observed for the two copolymer series; the situation was more conspicuous in the use of CB trunks.