Identification of a novel series of alkylitaconic acids in wood cultures of Ceriporiopsis subvermispora by gas chromatography/mass spectrometry.

A novel series of long-chain unsaturated dicarboxylic acids consisting of a long aliphatic chain attached to the C-3 position of itaconic acid has been identified by gas chromatography/mass spectrometry during in vitro decay of eucalypt wood by the white-rot basidiomycete Ceriporiopsis subvermispora. The major compounds were identified as tetradecyl-, 7-hexadecenyl- and hexadecylitaconic acids by their mass fragmentation patterns. Other members of the same compound series, identified as dodecanyl-, tridecanyl-, tetradecenyl-, pentadecanyl-, octadecenyl- and octadecanylitaconic acids, were present in very minor amounts or traces. Whereas hexadecenylitaconic acid has already been reported in cultures of C. subvermispora, to our knowledge this is the first report of the presence of the other alkylitaconic acids in fungal cultures. These new alkylitaconic-type metabolites may constitute a source for peroxidizable lipids involved in lignin degradation during wood decay by C. subvermispora and other white-rot basidiomycetes.     

Anti-Inflammatory Effects of Auranamide and Patriscabratine—Mechanisms and In Silico Studies

Auranamide and patriscabratine are amides from Melastoma malabathricum (L.) Smith. Their anti-inflammatory activity and nuclear factor erythroid 2-related factor 2 (NRF2) activation ability were evaluated using Escherichia coli lipopolysaccharide (LPSEc)-stimulated murine macrophages (RAW264.7) and murine hepatoma (Hepa-1c1c7) cells, respectively. The cytotoxicity of the compounds was assessed using a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. The anti-inflammatory activity was determined by measuring the nitric oxide (NO) production and pro-inflammatory cytokines (Interleukin (IL)-1β, Interferon (IFN)-γ, tumour necrosis factor (TNF)-α, and IL-6) and mediators (NF-κB and COX-2). NRF2 activation was determined by measuring the nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) quinone oxidoreductase 1 (NQO1), nuclear NRF2 and hemeoxygenase (HO)-1. In vitro metabolic stability was assessed using the mouse, rat, and human liver microsomes. The compounds were non-toxic to the cells at 10 μM. Both compounds showed dose-dependent effects in downregulating NO production and pro-inflammatory cytokines and mediators. The compounds also showed upregulation of NQO1 activity and nuclear NRF2 and HO-1 levels. The compounds were metabolically stable in mouse, rat and human liver microsomes. The possible molecular targets of NRF2 activation by these two compounds were predicted using molecular docking studies and it was found that the compounds might inhibit the Kelch domain of KEAP1 and GSK-3β activity. The physicochemical and drug-like properties of the test compounds were predicted using Schrodinger small molecule drug discovery suite (v.2022-2).     

Quenching of giant hysteresis effects in La(1-z)Y(z)Hx switchable mirrors

Hydrogen atoms adsorbed on TiO2(110)-(1x1) surfaces have been characterized by scanning tunneling microscopy (STM) combined with electron stimulated desorption (ESD) technique. Certain amounts of H atoms are unexpectedly found on the TiO2 surfaces annealed at 900 K. Two forms of adsorption were discriminated in STM images from the different sensitivity to ESD and tentatively assigned to hydroxyl-type (O-H) and hydride-type (Ti-H) species.     

Regiochemical control of monolignol radical coupling: a new paradigm for lignin and lignan biosynthesis

BACKGROUND: Although the lignins and lignans, both monolignol-derived coupling products, account for nearly 30% of the organic carbon circulating in the biosphere, the biosynthetic mechanism of their formation has been poorly understood. The prevailing view has been that lignins and lignans are produced by random free-radical polymerization and coupling, respectively. This view is challenged, mechanistically, by the recent discovery of dirigent proteins that precisely determine both the regiochemical and stereoselective outcome of monolignol radical coupling. RESULTS: To understand further the regulation and control of monolignol coupling, leading to both lignan and lignin formation, we sought to clone the first genes encoding dirigent proteins from several species. The encoding genes, described here, have no sequence homology with any other protein of known function. When expressed in a heterologous system, the recombinant protein was able to confer strict regiochemical and stereochemical control on monolignol free-radical coupling. The expression in plants of dirigent proteins and proposed dirigent protein arrays in developing xylem and in other lignified tissues indicates roles for these proteins in both lignan formation and lignification. CONCLUSIONS: The first understanding of regiochemical and stereochemical control of monolignol coupling in lignan biosynthesis has been established via the participation of a new class of dirigent proteins. Immunological studies have also implicated the involvement of potential corresponding arrays of dirigent protein sites in controlling lignin biopolymer assembly.