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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.

In this study, the influence of two subfractions (with previously proven anti-cancer properties) isolated from wood rot fungus Cerrena unicolor on the formation of a fibrin clot was investigated in the context of potential use as fibrin glue and sealant enhancers and potential wound healing agents. With the use of ROTEM thromboelastometry, we demonstrated that, in the presence of fibrinogen and thrombin, the S6 fraction accelerated the formation of a fibrin clot, had a positive effect on its elasticity modulus, and enhanced the degree of fibrin cross-linking. The S5 fraction alone showed no influence on the fibrin coagulation process; however, in the presence of fibrin, it exhibited a decrease in anti-proliferative properties against the HT-29 line, while it increased the proliferation of cells in general at a concentration of 100 µg/mL. Both fractions retained their proapoptotic properties to a lesser degree. In combination with the S6 fraction in the ratio of 1:1 and 1:3, the fractions contributed to increased inhibition of the activity of matrix metalloproteinases (MMPs). This may suggest anti-metastatic activity of the combined fractions. In conclusion, the potential of the fractions isolated from the C. unicolor secretome to be used as a means of improving the wound healing process was presented. The potential for delivering agents with cytostatic properties introduced far from the site of action or exerting a pro-proliferative effect at the wound site with the aid of a fibrin sealant was demonstrated.

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.

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