Project description:The metabolites of the genus Marasmius are diverse, showing good research prospects for finding new bioactive molecules. In order to explore the active metabolites of the fungi Marasmius berteroi, the deep chemical investigation on the bioactive compounds from its cultures was undertaken, which led to the isolation of three new naphthalene compounds dipolynaphthalenes A-B (1,2) and naphthone C (3), as well as 12 known compounds (4-15). Compounds 1, 2, and 4 are dimeric naphthalene compounds. Their structures were elucidated by MS, 1D and 2D NMR spectroscopic data, as well as ECD calculations. Compounds 2-4 and 7 exhibited acetylcholinesterase (AChE) inhibitory activities at the concentration of 50 μg/mL with inhibition ratios of 42.74%, 44.63%, 39.50% and 51.49%, respectively. Compounds 5 and 7,8 showed weak inhibitory activities towards two tumor cell lines, with IC50 of 0.10, 0.076 and 0.058 mM (K562) and 0.13, 0.18, and 0.15 mM (SGC-7901), respectively.
Project description:Fruiting body lectins have been proposed to act as effector proteins in the defense of fungi against parasites and predators. The Marasmius oreades agglutinin (MOA) is a lectin from the fairy ring mushroom with specificity for Gal?1-3Gal containing carbohydrates. This lectin is composed of an N-terminal carbohydrate-binding domain and a C-terminal dimerization domain. The dimerization domain of MOA shows in addition calcium-dependent cysteine protease activity, similar to the calpain family.Cell detachment assay, cell viability assay, immunofluorescence, live cell imaging and Western blot using MDCKII cell line.In this study, we demonstrate in MDCKII cells that after internalization, MOA protease activity induces profound physiological cellular responses, like cytoskeleton rearrangement, cell detachment and cell death. These changes are preceded by a decrease in FAK phosphorylation and an internalization and degradation of ?1-integrin, consistent with a disruption of integrin-dependent cell adhesion signaling. Once internalized, MOA accumulates in late endosomal compartments.Our results suggest a possible toxic mechanism of MOA, which consists of disturbing the cell adhesion and the cell viability.After being ingested by a predator, MOA might exert a protective role by diminishing host cell integrity.
Project description:The basidiomycete Marasmius quercophilus is commonly found during autumn on the decaying litter of the evergreen oak (Quercus ilex L.), a plant characteristic of Mediterranean forest. This white-rot fungus colonizes the leaf surface with rhizomorphs, causing a total bleaching of the leaf. In synthetic liquid media, this white-rot fungus has strong laccase activity. From a three-step chromatographic procedure, we purified a major isoform to homogeneity. The gene encodes a monomeric glycoprotein of approximately 63 kDa, with a 3.6 isoelectric point, that contains 12% carbohydrate. Spectroscopic analysis of the purified enzyme (UV/visible and electron paramagnetic resonance, atomic absorption) confirmed that it belongs to the "blue copper oxidase" family. With syringaldazine as the substrate, the enzyme's pH optimum was 4.5, the optimal temperature was 75 degrees C, and the K(m) was 7.1 microM. The structural gene, lac1, was cloned and sequenced. This gene encodes a 517-amino-acid protein 99% identical to a laccase produced by PM1, an unidentified basidiomycete previously isolated from wastewater from a paper factory in Spain. This similarity may be explained by the ecological distribution of the evergreen oak in Mediterranean forest.
| S-EPMC91924 | biostudies-literature
Project description:Linkage mapping of Marasmius oreades
Project description:An extracellular peroxygenase from Marasmius rotula was produced in liquid culture, chromatographically purified and partially characterized. This is the third aromatic peroxygenase (APO) that has been characterized in detail and the first one that can be produced in high yields. The highest enzyme levels of about 41,000 U l-1 (corresponding to appr. 445 mg l-1 APO protein) exceeded the hitherto reported levels more than 40-fold and were detected in carbon- and nitrogen-rich complex media. The enzyme was purified by FPLC to apparent homogeneity (SDS-PAGE) with a molecular mass of 32 kDa (27 kDa after deglycosylation) and isoelectric points between 4.97 and 5.27. The UV-visible spectrum of the native enzyme showed a characteristic maximum (Soret band) at 418 nm that shifted after reduction with sodium dithionite and flushing with carbon monoxide to 443 nm. The pH optimum of the M. rotula enzyme was found to vary between pH 5 and 6 for most reactions studied. The apparent Km-values for 2,6-dimethoxyphenol, benzyl alcohol, veratryl alcohol, naphthalene and H2O2 were 0.133, 0.118, 0.279, 0.791 and 3.14 mM, respectively. M. rotula APO was found to be highly stable in a pH range from 5 to 10 as well as in the presence of organic solvents (50% vol/vol) such as methanol, acetonitrile and N,N-dimethylformamide. Unlike other APOs, the peroxygenase of M. rotula showed neither brominating nor chlorinating activities.