A chemical investigation of secondary metabolites (SMs) from Aspergillus nidulans resulted in the identification of five novel dioxopiperazine (DKP)-diphenyl ether hybrids, designated as diphenylemestrins A-E (1-5). These compounds 1-5 represent the first known dimers combining DKP and diphenyl ether structures, with compound 4 featuring an uncommon dibenzofuran as the diphenyl ether component. The structural elucidation and determination of absolute stereochemistry were accomplished through spectroscopic analysis and electronic circular dichroism (ECD) calculations. Notably, diphenylemestrin C (3) exhibited moderate cytostatic activity against NB4 cells, with a half maximal inhibitory concentration (IC₅₀) value of 21.99 μmol·L^-1, and induced apoptosis at higher concentrations.
Aspergillus nidulans/metabolism* ; Diketopiperazines/pharmacology* ; Molecular Structure ; Phenyl Ethers/pharmacology* ; Humans ; Apoptosis/drug effects* ; Cell Line, Tumor

Echinocandin B (ECB) is a key precursor of the antifungal drug anidulafungin. It is a secondary metabolite of Aspergillus nidulans, and its titer in fermentation is significantly affected by the ECB synthesis pathway and cell morphology. In this study, the key genes related to the transcription activation, hydroxylation, and cell morphology during ECB biosynthesis were investigated to increase the fermentation titer of ECB and to change the cell morphology of Aspergillus nidulans to reduce the viscosity of the fermentation broth. The results indicated that after overexpression of ecdB and ecdK, the ECB titer increased by 25.8% and 23.7%, respectively, compared with that of the wild-type strain, reaching (2 030.5±99.2) mg/L and (1 996.4±151.4) mg/L. However, the deletion of fksA associated with cell wall synthesis resulted in damage to the cell wall, affecting strain growth and product synthesis. The engineered strain overexpressing ecdB was fermented in a 50-L bioreactor, in which the ECB titer reached 2 234.5 mg/L. The findings laid a research foundation for the subsequent metabolic engineering of this strain.
Fermentation ; Aspergillus nidulans/genetics* ; Echinocandins/genetics* ; Bioreactors/microbiology* ; Fungal Proteins/biosynthesis* ; Metabolic Engineering

Marine microorganisms, especially marine fungi, have historically proven their value as a prolific source for structurally novel and pharmacologically active secondary metabolites (Deshmukh et al., 2018; Carroll et al., 2022). The corals constitute a dominant part of reefs with the highest biodiversity, and harbor highly diverse and abundant microbial symbionts in their tissue, skeleton, and mucus layer, with species-specific core members that are spatially partitioned across coral microhabitats (Wang WQ et al., 2022). The coral-associated fungi were very recently found to be vital producers of structurally diverse compounds, terpenes, alkaloids, peptides, aromatics, lactones, and steroids. They demonstrate a wide range of bioactivity such as anticancer, antimicrobial, and antifouling activity (Chen et al., 2022). The genetically powerful genus Emericella (Ascomycota), which has marine and terrestrial sources, includes over 30 species and is distributed worldwide. It is considered a rich source of diverse secondary metabolites with antimicrobial activity or cytotoxicity (Alburae et al., 2020). Notably, Emericella nidulans, the sexual state of a classic biosynthetic strain Aspergillus nidulans, was recently reported as an important source of highly methylated polyketides (Li et al., 2019) and isoindolone-containing meroterpenoids (Zhou et al., 2016) with unusual skeletons.
Animals ; Aspergillus nidulans ; Polyketides/chemistry* ; Anthozoa/microbiology* ; Anti-Infective Agents/pharmacology* ; Alkaloids

Tyrosine-decahydrofluorene derivatives are a class of hybrid compounds that integrate the properties of polyketides and nonribosomal peptides. These compounds feature a [6.5.6] tricarbocyclic core and a para-cyclophane ether moiety in their structures and exhibit anti-tumor and anti-microbial activities. In this study, we constructed the biosynthetic pathway of xenoacremones from Xenoacremonium sinensis ML-31 in the Aspergillus nidulans host, resulting in the identification of four novel tyrosine-decahydrofluorene analogs, xenoacremones I-L (1-4), along with two known analogs, xenoacremones A and B. Remarkably, compounds 3 and 4 contained a 12-membered para-cyclophane ring system, which is unprecedented among tyrosine-decahydrofluorene analogs in X. sinensis. The successful reconstruction of the biosynthetic pathway and the discovery of novel analogs demonstrate the utility of heterologous expression strategy for the generation of structurally diverse natural products with potential biological activities.
Aspergillus nidulans/metabolism* ; Biological Products/metabolism* ; Polyketides/metabolism* ; Peptides/metabolism* ; Biosynthetic Pathways ; Multigene Family

Aims: Palm kernel cake (PKC) is a high-protein, high-energy food that is widely utilized in the animal feed business. However, the high fibre and limited amino acid content of untreated PKC were the main issues for it to be used as animal feed, particularly in non-ruminants. To improve the quality of PKC, this study combined the use of solid-state fermentation (SSF) and consortia of fungi and bacteria to treat the PKC. Methodology and results: Two fungi, Emericella nidulans (4DP5) and Cladosporium herbarum (7DF12) and three strains of bacteria, Bacillus subtilis, which were active mannanase producers, were used in different combinations to reduce the hemicellulose content and improve the crude protein content of PKC in a lab-scale solid-state fermentation. PKC inoculated separately with five types of mixed culture treatments were allowed to ferment. The fermentation conditions were 20% inoculum (w/v), 85-92% humidity, pH 7.0 and PKC particle size 0.8 mm. PKC treatments with two fungi, E. nidulans (4DP5) and C. herbarum (7DF12), as well as a fungus-bacterium combination, E. nidulans (4DP5) and B. subtilis, outperformed the other three treatments. The crude protein levels were increased by 3.34% and 1.86%, respectively, due to these treatments. Furthermore, the level of aflatoxins produced increased marginally but remained within the permissible limits. Conclusion, significance and impact of study The treated PKC has more sugar and crude protein and less than 20 parts per billion (ppb) of aflatoxin, making it appropriate for animal consumption. The SSF technique of combining fungi and Bacilli enhanced the nutritional and market value of PKC substantially, which can be upscaled.
Aspergillus nidulans ; Cladosporium ; Bacillus subtilis ; Palm Oil ; Fermentation

To develop a convenient promoter analysis system for fungi, a null-pigment mutant (NPG) of Aspergillus nidulans was used with the 4′-phosphopantetheinyl transferase (PPTase) gene, npgA, which restores the normal pigmentation in A. nidulans, as a new reporter gene. The functional organization of serially deleted promoter regions of the A. nidulans trpC gene and the Cryphonectria parasitica crp gene in filamentous fungi was representatively investigated to establish a novel fungal promoter assay system that depends on color complementation of the NPG mutant with the PPTase npgA gene. Several promoter regions of the trpC and crp genes were fused to the npgA gene containing the 1,034-bp open reading frame and the 966-bp 3’ downstream region from the TAA, and the constructed fusions were introduced into the NPG mutant in A. nidulans to evaluate color recovery due to the transcriptional activity of the sequence elements. Serial deletion of the trpC and crp promoter regions in this PPTase reporter assay system reaffirmed results in previous reports by using the fungal transformation step without a laborious verification process. This approach suggests a more rapid and convenient system than conventional analyses for fungal gene expression studies.
Aspergillus nidulans* ; Aspergillus* ; Complement System Proteins ; Fungi ; Genes, Fungal ; Genes, Reporter ; Open Reading Frames ; Pigmentation ; Promoter Regions, Genetic ; Transferases*

Anidulafungin is an effective antifungal medicine, which can inhibit activities of candida in vitro and in vivo. Echinocandin B (ECB) is the key precursor of Anidulafungin, thus the price and market prospect of Anidulafungin is directly due to the fermentation titer of ECB. In this study, Aspergillus nidulans was used for ECB fermentation, and the influence of adding microparticles on ECB fermentation was studied, such as talcum powder, Al2O3, and glass beads. The particle size and concentration were the key factors for mycelium morphology and ECB production, and ECB production could reach 1 262.9 mg/L and 1 344.1 mg/L by adding talcum powder of 20 g/L (d50 = 14.2 μm) and 7 glass beads (6 mm), an increase by 33.2% and 41.7%, respectively. The results indicated that the mycelium morphology of filamentous microorganisms and the product yield of fermentation could be improved by adding microparticles remarkably, and it provide an important method for the fermentative optimization of filamentous microorganisms.
Antifungal Agents ; metabolism ; Aspergillus nidulans ; metabolism ; Echinocandins ; biosynthesis ; Fermentation ; Fungal Proteins ; biosynthesis ; Industrial Microbiology ; methods

The fungi on Meju are known to play an important role as degrader of macromolecule of soybeans. In order to elucidate the origin of fungi on traditional Meju, mycobiota of the air both inside and outside traditional Meju fermentation rooms was examined. From 11 samples of air collected from inside and outside of 7 Meju fermentation rooms, 37 genera and 90 species of fungi were identified. In outside air of the fermentation room, Cladosporium sp. and Cladosporium cladosporioides were the dominant species, followed by Cladosporium tenuissimum, Eurotium sp., Phoma sp., Sistotrema brinkmannii, Alternaria sp., Aspergillus fumigatus, Schizophyllum commune, and Penicillium glabrum. In inside air of the fermentation room, Cladosporium sp., Aspergillus oryzae, Penicillium chrysogenum, Asp. nidulans, Aspergillus sp., Cla. cladosporioides, Eurotium sp., Penicillium sp., Cla. tenuissimum, Asp. niger, Eur. herbariorum, Asp. sydowii, and Eur. repens were collected with high frequency. The concentrations of the genera Aspergillus, Eurotium, and Penicillium were significantly higher in inside air than outside air. From this result and those of previous reports, the origin of fungi present on Meju was inferred. Of the dominant fungal species present on Meju, Lichtheimia ramosa, Mucor circinelloides, Mucor racemosus, and Scopulariopsis brevicaulis are thought to be originated from outside air, because these species are not or are rarely isolated from rice straw and soybean; however, they were detected outside air of fermentation room and are species commonly found in indoor environments. However, Asp. oryzae, Pen. polonicum, Eur. repens, Pen. solitum, and Eur. chevalieri, which are frequently found on Meju, are common in rice straw and could be transferred from rice straw to Meju. The fungi grow and produce abundant spores during Meju fermentation, and after the spores accumulate in the air of fermentation room, they could influence mycobiota of Meju fermentation in the following year. This could explain why concentrations of the genera Aspergillus, Eurotium, and Penicillium are much higher inside than outside of the fermentation rooms.
Alternaria ; Aspergillus ; Aspergillus fumigatus ; Aspergillus nidulans ; Aspergillus oryzae ; Cladosporium ; Eurotium ; Fermentation* ; Fungi* ; Mucor ; Niger ; Oryza ; Penicillium ; Penicillium chrysogenum ; Schizophyllum ; Scopulariopsis ; Soybeans ; Spores ; Viperidae

We have previously isolated epsilon-COP, the alpha-COP interactor in COPI of Aspergillus nidulans, by yeast two-hybrid screening. To understand the function of epsilon-COP, the aneA+ gene for epsilon-COP/AneA was deleted by homologous recombination using a gene-specific disruption cassette. Deletion of the epsilon-COP gene showed no detectable changes in vegetative growth or asexual development, but resulted in decrease in the production of the fruiting body, cleistothecium, under conditions favorable for sexual development. Unlike in the budding yeast Saccharomyces cerevisiae, in A. nidulans, over-expression of epsilon-COP did not rescue the thermo-sensitive growth defect of the alpha-COP mutant at 42degrees C. Together, these data show that epsilon-COP is not essential for viability, but it plays a role in fruiting body formation in A. nidulans.
Aspergillus nidulans* ; Coatomer Protein* ; Fruit ; Homologous Recombination ; Mass Screening ; Saccharomyces cerevisiae ; Saccharomycetales ; Sexual Development ; Yeasts

Small, cysteine-rich, highly stable antifungal proteins secreted by filamentous Ascomycetes have great potential for the development of novel antifungal strategies. However, their practical application is still limited due to their not fully clarified mode of action. The aim of this work was to provide a deep insight into the antifungal mechanism of Neosartorya fischeri antifungal protein (NFAP), a novel representative of this protein group. Within a short exposure time to NFAP, reduced cellular metabolism, apoptosis induction, changes in the actin distribution and chitin deposition at the hyphal tip were observed in NFAP-sensitive Aspergillus nidulans. NFAP did show neither a direct membrane disrupting-effect nor uptake by endocytosis. Investigation of A. nidulans signalling mutants revealed that NFAP activates the cAMP/protein kinase A pathway via G-protein signalling which leads to apoptosis and inhibition of polar growth. In contrast, NFAP does not have any influence on the cell wall integrity pathway, but an unknown cell wall integrity pathway-independent mitogen activated protein kinase A-activated target is assumed to be involved in the cell death induction. Taken together, it was concluded that NFAP shows similarities, but also differences in its mode of antifungal action compared to two most investigated NFAP-related proteins from Aspergillus giganteus and Penicillium chrysogenum.
Actins ; metabolism ; Antifungal Agents ; pharmacology ; Apoptosis ; drug effects ; Aspergillus nidulans ; cytology ; drug effects ; growth & development ; Cell Membrane ; drug effects ; metabolism ; Cell Wall ; drug effects ; metabolism ; Chitin ; metabolism ; Endocytosis ; drug effects ; Fungal Proteins ; pharmacology ; GTP-Binding Proteins ; metabolism ; Hyphae ; cytology ; drug effects ; Microbial Viability ; drug effects ; Neosartorya ; chemistry ; Signal Transduction ; drug effects