Effect of Ferulic Acid, a Phenolic Inducer of Fungal Laccase, on 26S Proteasome Activities In Vitro

Comparative Proteomic Analysis Reveals Candidate Pathways Related to the Effect of Different Light Qualities on the Development of Mycelium and Fruiting Body of Pleurotus ostreatus

Light affects the morphology and physiology of Pleurotus ostreatus. However, the underlying molecular mechanism of this effect remains unclear. In this study, a label-free comparative proteomic analysis was conducted to investigate the global protein expression profile of the mycelia and fruiting bodies of P. ostreatus PH11 growing under four different light quality treatments. Among all the 2234 P. ostreatus proteins, 1349 were quantifiable under all tested conditions. A total of 1100 differentially expressed proteins were identified by comparing the light group data with those of the darkness group. GO and KEGG enrichment analyses indicated that the oxidative phosphorylation, proteasome, and mRNA surveillance pathways were the most related pathways under the light condition. qRT-PCR verified that the expression of the white collar 1 protein was significantly enhanced under white light. Additionally, glutamine synthetase and aldehyde dehydrogenase played important roles during light exposure. This study provides valuable insight into the P. ostreatus light response mechanism, which will lay the foundation for improved cultivation.

Stone fruit phenolic and triterpenoid compounds modulate gene expression of Monilinia spp. in culture media

Phenolic and triterpenoid compounds are essential components in stone fruit skin and flesh tissues. They are thought to possess general antimicrobial activity. However, regarding brown rot disease, investigations were only confined to a limited number of phenolics, especially chlorogenic acid. The activity of triterpenoids against Monilinia spp., as an essential part of the peach cuticular wax, has not been studied before. In this work, the anti-fungal effect of some phenolics, triterpenoids, and fruit surface compound (FSC) extracts of peach fruit at two developmental stages were investigated on Monilinia fructicola and Monilinia laxa characteristics during in vitro growth. A new procedure for assaying anti-fungal activity of triterpenoids, which are notoriously difficult to assess in vitro because of their hydrophobicity, has been developed. Measurements of colony diameter, sporulation, and germination of second-generation conidia were recorded. Furthermore, the expression of twelve genes of M. fructicola associated with germination and/or appressorium formation and virulence-related genes was studied relative to the presence of the compounds. The study revealed that certain phenolics and triterpenoids showed modest anti-fungal activity while dramatically modulating gene expression in mycelium of M. fructicola on culture medium. MfRGAE1 gene was overexpressed by chlorogenic and ferulic acids and MfCUT1 by betulinic acid, at 4- and 7- days of mycelium incubation. The stage II FSC extract, corresponding to the period when the fruit is resistant to Monilinia spp., considerably up-regulated the MfLAE1 gene. These findings effectively contribute to the knowledge of biochemical compounds effects on fungi on in vitro conditions.

Plant Metabolites Affect Fusarium proliferatum Metabolism and In Vitro Fumonisin Biosynthesis

Fusarium proliferatum is a common hemi-biotrophic pathogen that infect a wide range of host plants, often leading to substantial crop loss and yield reduction. F. proliferatum synthesizes various mycotoxins, and fumonisins B are the most prevalent. They act as virulence factors and specific effectors that elicit host resistance. The effects of selected plant metabolites on the metabolism of the F. proliferatum strain were analyzed in this study. Quercetin-3-glucoside (Q-3-Glc) and kaempferol-3-rutinoside (K-3-Rut) induced the pathogen's growth, while DIMBOA, isorhamnetin-3-O-rutinoside (Iso-3-Rut), ferulic acid (FA), protodioscin, and neochlorogenic acid (NClA) inhibited fungal growth. The expression of seven F. proliferatum genes related to primary metabolism and four FUM genes was measured using RT-qPCR upon plant metabolite addition to liquid cultures. The expression of CPR6 and SSC1 genes was induced 24 h after the addition of chlorogenic acid (ClA), while DIMBOA and protodioscin reduced their expression. The transcription of FUM1 on the third day of the experiment was increased by all metabolites except for Q-3-Glc when compared to the control culture. The expression of FUM6 was induced by protodioscin, K-3-Rut, and ClA, while FA and DIMBOA inhibited its expression. FUM19 was induced by all metabolites except FA. The highest concentration of fumonisin B₁ (FB₁) in control culture was 6.21 µg/mL. Protodioscin did not affect the FB content, while DIMBOA delayed their synthesis/secretion. Flavonoids and phenolic acids displayed similar effects. The results suggest that sole metabolites can have lower impacts on pathogen metabolism and mycotoxin synthesis than when combined with other compounds present in plant extracts. These synergistic effects require additional studies to reveal the mechanisms behind them.

Design, Synthesis, and Antifungal Activities of Hymexazol Glycosides Based on a Biomimetic Strategy

Hymexazol (HYM) is irreplaceable for treating soil-borne diseases due to its high efficiency and low cost, as a broad-spectrum fungicide. However, when HYM is absorbed by plants, it is rapidly converted into two glycoside metabolites, and the antifungal activities of these glycosides are inferior to that of HYM. Therefore, in this study, to maintain strong antifungal activity in vitro and in vivo, HYM was glycosylated with amino sugars that have diverse biological activities to simulate plant glycosylation. The antifungal experiment proved that glycoside 15 has the highest antifungal activity, and N-acetyl glucosamine and HYM had obvious synergistic effects. According to the structure-activity relationship studies, glycoside 15 had greater numbers of active electron-rich regions and front-line orbital electrons due to the introduction of N-acetyl glucosamine. Moreover, glycoside 15 can significantly promote plant growth and induce an increase in plant defense enzyme activity. Additionally, compared to HYM, the results of electron microscopy and proteomics revealed that glycoside 15 has a unique antifungal mechanism. The promising antifungal activity and interactions with plants mean that glycoside 15 is a potential green fungicide candidate. Furthermore, this research conducted an interesting exploration of the agricultural applications of amino sugars.

Gamma-oryzanol alleviates intervertebral disc degeneration development by intercepting the IL-1β/NLRP3 inflammasome positive cycle

BACKGROUND

Intervertebral disc degeneration (IVDD) is a highly prevalent musculoskeletal disorder characterized by a local inflammatory response associated with the IL-1β/NLRP3 inflammasome positive feedback loop. Rice bran-derived gamma-oryzanol (Ory) as a sterol ferulate has attracted much attention due to its powerful anti-inflammatory, hypoglycemic and hypolipidemic health effects. As a clinical pharmaceutical for autonomic disorders, Ory's role in musculoskeletal degenerative disease remains unknown.

PURPOSE

This study aims to validate the role of Ory in IVDD and explore the potential mechanism.

STUDY DESIGN

Establishing the in vitro and in vivo IVDD models to detect the protective effect and molecular mechanism of Ory.

METHOD

The anti-ECM degradation, antioxidant and anti-NLRP3 inflammasome activation effects of Ory on IL-1β-stimulated nucleus pulposus (NP) cells were assessed by immunoblotting and immunofluorescence, etc. MRI, S-O staining and immunohistochemistry were performed to estimate the effects of Ory administration on acupuncture-mediated IVDD in rats at imaging and histological levels.

RESULTS

Ory treatment inhibited IL-1β-mediated ECM degradation, oxidative stress and NLRP3 inflammasome activation in NP cells. By interfering with NF-κB signaling and ROS overproduction, Ory interrupted IL-1β/NLRP3-inflammasome positive cycle. In vivo experiments showed that Ory delayed acupuncture-mediated IVDD development.

CONCLUSION

Our results support the potential application of Ory as a therapeutic compound for IVDD.

Cerrena unicolor Laccases, Genes Expression and Regulation of Activity

A white rot fungus Cerrena unicolor has been identified as an important source of laccase, unfortunately regulation of this enzyme genes expression is poorly understood. Using 1D and 2D PAGE and LC-MS/MS, laccase isoenzymes were investigated in the liquid filtrate of C. unicolor culture. The level of expression of laccase genes was measured using qPCR. The elevated concentrations of copper and manganese in the medium caused greatest change in genes expression and three laccase transcripts were significantly affected after culture temperature was decreased from 28 to 4 °C or increased to 40 °C. The small differences in the PAGE band intensities of individual laccase proteins were also observed, indicating that given compound affect particular laccase’s transcript. Analyses of laccase-specific activity, at all tested conditions, showed the increased activities as compared to the control, suggesting that enzyme is regulated at the post-translational stage. We observed that the aspartic protease purified from C. unicolor, significantly stimulate laccase activity. Moreover, electrochemical analysis of protease-treated laccase sample had 5 times higher redox peaks. The obtained results indicate that laccases released by C. unicolor are regulated at transcriptional, translational, and at the post-translational steps of gene expression helping fungus adapt to the environmental changes.

Lighting Conditions Influence the Dynamics of Protease Synthesis and Proteasomal Activity in the White Rot Fungus Cerrena unicolor

Recent transcriptomic and biochemical studies have revealed that light influences the global gene expression profile and metabolism of the white-rot fungus Cerrena unicolor. Here, we aimed to reveal the involvement of proteases and ubiquitin-mediated proteolysis by the 26S proteasome in the response of this fungus to white, red, blue and green lighting conditions and darkness. The changes in the expression profile of C. unicolor genes putatively engaged in proteolysis were found to be unique and specific to the applied wavelength of light. It was also demonstrated that the activity of proteases in the culture fluid and mycelium measured using natural and synthetic substrates was regulated by light and was substrate-dependent. A clear influence of light on protein turnover and the qualitative and quantitative changes in the hydrolytic degradation of proteins catalyzed by various types of proteases was shown. The analysis of activity associated with the 26S proteasome showed a key role of ATP-dependent proteolysis in the initial stages of adaptation of fungal cells to the stress factors. It was suggested that the light-sensing pathways in C. unicolor are cross-linked with stress signaling and secretion of proteases presumably serving as regulatory molecules.