Inhibitory Potential of New Phenolic Hydrazide-Hydrazones with a Decoy Substrate Fragment towards Laccase from a Phytopathogenic Fungus: SAR and Molecular Docking Studies.

Laccase from pathogenic fungi participates in both the delignification and neutralization of phytoantibiotics. Furthermore, it interferes with the hormone signaling in plants and catalyzes melanization. Infections of these pathogens contribute to loss in forestry, agriculture, and horticulture. As there is still a need to expand knowledge on efficient defense strategies against phytopathogenic fungi, the present study aimed to reveal more information on the molecular mechanisms of laccase inhibition with natural and natural-like carboxylic acid semi-synthetic derivatives. A set of hydrazide-hydrazones derived from carboxylic acids, generally including electron-rich arene units that serve as a decoy substrate, was synthesized and tested with laccase from Trametes versicolor. The classic synthesis of the title inhibitors proceeded with good to almost quantitative yield. Ninety percent of the tested molecules were active in the range of KI = 8-233 µM and showed different types of action. Such magnitude of inhibition constants qualified the hydrazide-hydrazones as strong laccase inhibitors. Molecular docking studies supporting the experimental data explained the selected derivatives' interactions with the enzyme. The results are promising in developing new potential antifungal agents mitigating the damage scale in the plant cultivation, gardening, and horticulture sectors.

Synchrotron X-ray micro-tomography imaging and analysis of wood degraded by Physisporinus vitreus and Xylaria longipes.

Incubation of Norway spruce with Physisporinus vitreus and sycamore with Xylaria longipes results in reduction in density of these wood species that are traditionally used for the top and bottom plate of a violin, which follows by enhanced acoustic properties. We used Synchrotron X-ray micro-tomography, to study the three-dimensional structure of wood at the micro-scale level and the alterations of the density distribution after incubation with two white-rot fungi. Micro-tomography data from wood treated at different incubation periods are analyzed and compared with untreated (control) specimens to determine the wood density map and changes at the cell-wall level. Differences between the density of early- and latewood, xylem ray and around bordered pits in both Norway spruce and sycamore are studied. Three-dimensional hyphal networks of the P.vitreus and Xylaria longipes hyphae are visualized inside the cell lumina and their significance on the density of the early- and latewood cells after different incubation periods are discussed. The study illustrates the utility of X-ray micro-tomography for both qualitative and quantitative studies of a wide variety of biological systems and due to its high sensitivity, small structural changes can be quantified.

[Bioactivity of Laetiporus sulphureus var. sulphureus metabolites in liquid culture].

The liquid culture of Laetiporus sulphureus var. sulphureus was lethal against fruit fly. It was found that extracellular metabolites were primary causation of the lethal effect against fruit fly, which was influenced by pH value. Isolation and analysis with ion-exchange resin column chromatography and HPLC demonstrated that oxalic acid was present in supernatant of Laetiporus sulphureus var. sulphureus, and it was one of the contributing factors to lethal effect against fruit fly and decrease of pH value of culture system. When cultured in airlift reactor, concentration of oxalic acid, quantity of mycelia and pH value was correlated with each other. Further analysis on elution revealed that a kind of oligidic pigment of amaranth in alkaline condition were also lethal against fruit fly.

[Potential teratogenic action of the mycelium of the higher fungus, Polyporellus squamosus]. / Prouchvane ne vuzmozhnoto teratogenno deistvie na mitsel ot visshata guba Polyporellus squamosus.

The influence on the embryonic development of food with only source of protein derived from the mycelium of the higher fungus Polyporellus squamosus, was studied in a group of 90 pregnant rats. Animals fed caseine and standard food pressed into briquettes as source of protein served as controls. On the 17-th and 18-th gestation day 8 animals were examined and the number of of lutein bodies and fetuses was checked up. Anomalies were serched in the fetuses, by use of the method of Dawson and Wilson. The progeny of rats treated during gestation was examined on the 21-st day of life, by using a number of blood, integral and biochemical parameters (GOT, GPT, AP, SDH, catalase, sulfhydryl groups, soluble, protein). Proceeding from the results obtained, the authors rule out any teratogenic and embryotoxic activity of the mycelium of Polyporellus squamosus, under the aforegoing experimental conditions.