Search Results (64)

Trichosporon austroamericanum is a recently described yeast species related to Trichosporon inkin and exclusively isolated from clinical specimens. However, its genomic features and pathogenic potential remain poorly understood. In this study, we performed whole-genome sequencing on three blood-derived isolates from patients with invasive fungal infections and comparative analyses with 13 related Trichosporon species. The three isolates yielded high-quality assemblies of 9–10 scaffolds (~21 Mb), facilitating reliable comparisons. While most species had comparable genome sizes, Trichosporon ovoides, Trichosporon coremiiforme, and Cutaneotrichosporon mucoides displayed large, fragmented genomes, suggestive of polyploidy. ANI analysis and phylogenetic trees based on ANI and single-copy orthologs supported the classification of T. austroamericanum as a distinct clade with moderate intraspecific divergence. Using the Galleria mellonella, a model for fungal pathogenicity, all T. austroamericanum strains reduced larval survival, and NIIDF 0077300 exhibited virulence comparable to T. asahii and greater than T. inkin. To explore the gene-level differences associated with pathogenicity, we performed ortholog analysis based on single-copy genes. This revealed a unique Zn(II)₂Cys₆-type transcription factor gene (OG0010545) present only in NIIDF 0077300 and T. asahii. These findings highlight the genomic diversity and infection-associated traits of T. austroamericanum, providing a framework for future functional studies. Full article

Zygophyllum coccineum L. and Haloxylon salicornicum are dominant plant species in the natural habitats of Saudi Arabia. The soil microbiome is indispensable for nutrient cycling and stress resilience. In the present study, the analysis of soil nutrients under the two plants displayed variable differences in total N, K, Zn, Mn and Cu, with significant differences in both K and Mn (p ≤ 0.05). In general, the available soil nutrients were higher under Haloxylon than Zygophyllum plants, reflecting higher N, K, Fe and Cu contents in the leaves of the Haloxylon plant. Metagenomic analysis of soil microbiome revealed that the top abundant bacteria at the phylum level were Actinobacteriota, Chloroflexi and Proteobacteria, whereas the uppermost fungal communities were Ascomycota, followed by Basidiomycota. The predicted abundant enzymes in the bacterial communities included Phosphoadenylyl-sulfate reductase, Serine-type D-Ala-carboxypeptidase, ADP-glyceromanno-heptose 6-epimerase and glutathione hydrolase. The fungal communities associated with Haloxylon possessed more than 48 enzymes that differed in their richness from the communities of Zygophyllum. Pentose-P and Sulphate-Cys pathways disclosed the extreme abundant pathways in Zygophyllum bacterial communities, while the nonoxipent pathway was overabundant in the Haloxylon fungal communities. While genomic predictions provide insights into functional potential, integrating these data with environmental parameters remains key to managing soil health. Full article

Transcription factors Fzc9 and Pdr802, characterized by their Zn₂Cys₆ DNA-binding domain, are essential for the virulence of Cryptococcus neoformans in lung and brain infections. Notably, the in vivo roles of Fzc9 and Pdr802 in contributing to the pathogenicity of C. neoformans are not adequately reflected by the phenotypic characteristics observed in vitro. This study investigates the effects of gene deletion of FZC9 or PDR802 on the proteomic and metabolomic profiles of C. neoformans. Using mass spectrometry analysis, we identified significant changes in protein abundance and metabolite levels, particularly in pathways related to ATP synthesis. These findings deepen our understanding of the metabolic roles of Fzc9 and Pdr802, suggesting potential targets for the development of novel therapeutic strategies against C. neoformans infections. Full article

Compared to natural enzymes, the development of efficient artificial simulated enzymes, such as those based on bimetallic materials with high catalytic activity and good stability, is an important way until now. Herein, we employed ZnCo₂O₄ microspheres as carriers to synthesize Pt-doped composites with different amounts using a one-pot method. The morphology and structure of the synthesized materials were characterized using XRD, SEM, BET, FT-IR, XPS, and Zeta potential techniques. It was found that Pt⁰ adhered well to the surface of ZnCo₂O₄ microspheres, with a 12.5% Pt doped ratio exhibiting abundant oxygen vacancies, excellent substrate affinity, and high peroxidase-like activity. Using fluorescent probes and electrochemical methods, the peroxidase-like catalytic mechanism has been explored that Pt@ZnCo₂O₄ microspheres can accelerate the electron transfer between H₂O₂ and 3,3′,5,5′-tetramethylbenzidine (TMB). Based on the optimal loading ratio of 12.5% of Pt@ZnCo₂O₄, a colorimetric sensor for visual detection of L-cysteine (L-Cys) was constructed, exhibiting a wide linear range of 0.1~50 µM and a low detection limit of 0.0163 µM. The sensor possesses good selectivity, reusability, and usage stability, which can be well applied to the determination of L-Cys in health product capsules with recovery rates of 96.9%~103.7% and RSD of 1.07%~6.50%. This work broadens the application prospects of spinel materials such as ZnCo₂O₄ in the field of biological analysis and also provides inspiration for the development of new artificial simulated enzymes. Full article

Enzyme-mediated protein degradation is a major concern in industrial fungal strain improvement, making low-proteolytic strains preferable for enhanced protein production. Here, we improved food-grade Aspergillus oryzae BCC7051 by manipulating the transcriptional regulation of protease-encoding genes. Genome mining of the transcription factor AoprtR and computational analysis confirmed its deduced amino acid sequence sharing evolutionary conservation across Aspergillus and Penicillium spp. The AoPrtR protein, which is classified into the Zn(II)2-Cys6-type transcription factor family, manipulates both intra- and extracellular proteolytic enzymes. Our transcriptional analysis indicated that the regulation of several protease-encoding genes was AoPrtR-dependent, with AoPrtR acting as a potent activator for extracellular acid-protease-encoding genes and a likely repressor for intracellular non-acid-protease-encoding genes. An indirect regulatory mechanism independent of PrtR may enhance proteolysis. Moreover, AoPrtR disruption increased extracellular esterase production by 2.55-fold, emphasizing its role in protein secretion. Our findings highlight the complexity of AoPrtR-mediated regulation by A. oryzae. Manipulation of regulatory processes through AoPrtR prevents secreted protein degradation and enhances the quantity of extracellular proteins, suggesting the low-proteolytic variant as a promising platform for the production of these proteins. This modified strain has biotechnological potential for further refinement and sustainable production of bio-based products in the food, feed, and nutraceutical industries. Full article

Gold nanoclusters (AuNCs) have been widely investigated because of their unique photoluminescence properties. However, the applications of AuNCs are limited by their poor stability and relatively low fluorescence. In the present work, we developed nanocomposites (L-Cys-AuNCs@ZIF-8) with high fluorescence and stability, which were constructed by encapsulating the water-dispersible L-Cys-AuNCs into a ZIF-8 via Zn²⁺-triggered growth strategy without high temperature and pressure. The maximum emission wavelength of the L-Cys-AuNCs@ZIF-8 composite was at 868 nm, and the fluorescence intensity of L-Cys-AuNCs@ZIF-8 was nearly nine-fold compared with L-Cys-AuNCs without the ZIF-8 package. The mechanism investigation by fluorescence spectroscopy and X-ray photoelectron spectroscopy showed that L-Cys-AuNCs@ZIF-8 impeded ligand rotation, induced energy dissipation, and diminished the self-quenching effect, attributing to the spatial distribution of L-Cys-AuNCs. Based on the high fluorescence efficiency of L-Cys-AuNCs@ZIF-8, a “signal off” detective platform was proposed with copper ions as a model analyte, achieving a sensitive detection limit of Cu²⁺ at 16.7 nM. The quenching mechanism was confirmed, showing that the structure of the L-Cys-AuNCs@ZIF-8 nanocomposites was collapsed by the addition of Cu²⁺. Attributing to the strong adsorption ability between copper ions and pyridyl nitrogen, the as-prepared L-Cys-AuNCs@ZIF-8 was shown to accumulate Cu²⁺, and the Zn²⁺ in ZIF-8 was replaced by Cu²⁺. Full article

The filamentous fungus Penicillium verruculosum (anamorph Talaromyces verruculosus) has been shown to be an efficient producer of secreted cellulases, used in biorefinery processes. Understanding the mechanisms of regulation of cellulase gene expression in the fungus P. verruculosum is a current task in industrial biotechnology, since it allows for targeted changes in the composition of the complex secreted by the fungus. Expression of cellulase genes in fungi is regulated mainly at the level of transcription via pathway-specific transcription factors (TF), the majority of which belong to the Zn(II)2Cys6 family of zinc binuclear cluster proteins. Transcriptional regulation of cellulase genes may have a species-specific pattern and involves several transcription factors. In this study, we used a qPCR method and transcriptome analysis to investigate the effect of knockouts and constitutive expression of genes encoding homologues of the regulatory factors XlnR and ClrB from P. verruculosum on the transcription of cbh1, egl2, and bgl1 genes, encoding three key cellulases, cellobiohydrolase, endoglucanase, and β-glucosidase, in the presence of various inducers. We have shown that the transcription factor XlnR of the filamentous fungus P. verruculosum is strictly responsible for the transcription of the main cellulolytic genes (cbh1, egl2, and bgl1) in the presence of xylose and xylobiose, but not in the presence of cellobiose. ClrB/Clr-2, a homologue from P. verruculosum, does not represent the main transcription factor regulating transcription of cellulolytic genes in the presence of selected inducers, unlike in the cases of Aspergillus nidulans, Aspergillus niger, and Penicillium oxalicum; apparently, it has a different function in fungi from the genus Talaromyces. We have also shown that constitutive expression of the transcription factor XlnR resulted in 3.5- and 2-fold increases in the activity of xylanase and β-glucosidase in a B1-XlnR enzyme preparation, respectively. In a practical sense, the obtained result can be used for the production of enzyme preparations based on the P. verruculosum B1-XlnR strain used for the bioconversion of renewable cellulose-containing raw materials into technical sugars. Full article

Colletotrichum lindemuthianum is the most frequent pathogenic fungus of the common bean Phaseolus vulgaris. This filamentous fungus employs a hemibiotrophic nutrition/infection strategy, which is characteristic of many Colletotrichum species. Due to host–pathogen coevolution, C. lindemuthianum includes pathotypes with a diversity of virulence against differential common bean varieties. In this study, we performed comparative genomic analyses on three pathotypes with different virulence levels and a non-pathogenic pathotype, isolated from different geographical areas in Mexico. Our results revealed large genomes with high transposable element contents that have undergone expansions, generating intraspecific diversity. All the pathotypes exhibited a similar number of clusters of orthologous genes (COGs) and Gene Ontology (GO) terms. TFomes contain families that are typical in fungal genomes; however, they show different contents between pathotypes, mainly in transcription factors with the fungal-specific TF and Zn2Cys6 domains. Peptidase families mainly contain abundant serine peptidases, metallopeptidases, and cysteine peptidases. In the secretomes, the number of genes differed between the pathotypes, with a high percentage of candidate effectors. Both the virulence gene and CAZyme gene content for each pathotype was abundant and diverse, and the latter was enriched in hemicellulolytic enzymes. We provide new insights into the nature of intraspecific diversity among C. lindemuthianum pathotypes and the origin of their ability to rapidly adapt to genetic changes in its host and environmental conditions. Full article

The entomopathogenic fungus (EPF) Metarhizium acridum is a typical filamentous fungus and has been used to control migratory locusts (Locusta migratoria manilensis). This study examines the impact of the Zn(II)2Cys6 transcription factor, MaAzaR, in the virulence of M. acridum. Disruption of MaAzaR (ΔMaAzaR) diminished the fungus’s ability to penetrate the insect cuticle, thereby decreasing its virulence. The median lethal time (LT₅₀) for the ΔMaAzaR strain increased by approximately 1.5 d compared to the wild-type (WT) strain when topically inoculated, simulating natural infection conditions. ΔMaAzaR compromises the formation, turgor pressure, and secretion of extracellular hydrolytic enzymes in appressoria. However, the growth ability of ΔMaAzaR within the hemolymph is not impaired; in fact, it grows better than the WT strain. Moreover, RNA-sequencing (RNA-Seq) analysis of ΔMaAzaR and WT strains grown for 20 h on locust hindwings revealed 87 upregulated and 37 downregulated differentially expressed genes (DEGs) in the mutant strain. Pathogen–host interaction database (PHI) analysis showed that about 40% of the total DEGs were associated with virulence, suggesting that MaAzaR is a crucial transcription factor that directly regulates the expression of downstream genes. This study identifies a new transcription factor involved in EPF cuticle penetration, providing theoretical support and genetic resources for the developing highly virulent strains. Full article

Entomopathogenic fungi are valuable sources of biological pesticides, with conidial yield and quality being pivotal factors determining their broad applications. AzaR, a fungus-specific zinc-cluster transcription factor, is known to regulate the biosynthesis of polyketone secondary metabolites in Aspergillus niger; however, its role in pathogenic fungi remains unclear. This study investigated the role of MaAzaR in the growth, development, and environmental tolerance of Metarhizium acridum. MaAzaR deletion slowed down conidial germination rate, caused reduction in conidial yield, lowered fungal tolerance to UV radiation, did not affect fungal heat-shock tolerance, and increased fungal sensitivity to the cell-wall-destructive agent calcofluor white. Furthermore, MaAzaR deletion transformed microcycle conidiation to normal conidiation on the microcycle conidiation medium. Transcription profile analysis demonstrated that MaAzaR could regulate transformation of the conidiation pattern by controlling the expression of genes related to cell division, mycelium growth and development, and cell wall integrity. Thus, this study identified a new gene related to fungal conidiation and environmental tolerance, enriching our understanding of the molecular mechanism of microcycle conidiation and providing theoretical support and genetic resources for the development of high-yielding strains. Full article

Aims: The study aimed to evaluate the effects of dietary folic acid (FA) on the production performance of laying hens, egg quality, and the nutritional differences between eggs fortified with FA and ordinary eggs. Methods: A total of 288 26-week-old Hy-Line Brown laying hens (initial body weights 1.65 ± 0.10 kg) with a similar weight and genetic background were used. A completely randomized design divided the birds into a control group and three treatment groups. Each group consisted of six replicates, with twelve chickens per replicate. Initially, all birds were fed a basal diet for 1 week. Subsequently, they were fed a basal diet supplemented with 0, 5, 10, or 15 mg/kg FA in a premix for a duration of 6 weeks. Results: Supplementation of FA could significantly (p < 0.05) enhance the FA content in egg yolks, particularly when 10 mg/kg was used, as it had the most effective enrichment effect. Compared to the control group, the Glu content in the 10 and 15 mg/kg FA groups showed a significant (p < 0.05) decrease. Additionally, the contents of Asp, Ile, Tyr, Phe, Cys, and Met in the 15 mg/kg FA group were significantly (p < 0.05) lower compared to the other groups. Adding FA did not have significant effects on the levels of vitamin A and vitamin E in egg yolk, but the vitamin D content in the 5 and 10 mg/kg FA groups showed a significant (p < 0.05) increase. Furthermore, the addition of FA did not have a significant effect on the levels of Cu, Fe, Mn, Se, and Zn in egg yolk. The dietary FA did not have a significant effect on the total saturated fatty acids (SFA) and polyunsaturated fatty acid (PUFA) content in egg yolk. However, the total monounsaturated fatty acid (MUFA) content in the 5 and 10 mg/kg groups significantly (p < 0.05) increased. These changes in nutritional content might be attributed to the increased very low-density lipoprotein (VLDL) protein content. The significant decrease in solute carrier family 1 Member 1 (SLC1A1), solute carrier family 1 Member 2 (SLC1A2), and solute carrier family 1 Member 3 (SLC1A3) gene expression compared to the control group appeared to be the reason for the decrease in amino acid content in egg yolk within the dietary FA group. Conclusion: The findings suggest that the appropriate addition of FA can enhance the levels of MUFA and vitamin D in egg yolks, thereby improving their nutritional value. Excessive intake of FA can decrease the effectiveness of enriching FA in egg yolk and impact the enrichment of certain amino acids. The yolk of eggs produced by adding 10 mg/kg of FA to the feed contains the optimal amount of nutrients. This study informs consumers purchasing FA-fortified eggs. Full article

Sclerotinia sclerotiorum is a fungal pathogen with a broad range of hosts, which can cause diseases and pose a great threat to many crops. Fungal-specific Zn₂Cys₆ transcription factors (TFs) constitute a large family prevalent among plant pathogens. However, the function of Zn₂Cys₆ TFs remains largely unknown. In this study, we identified and characterized SsZNC1, a Zn₂Cys₆ TF in S. sclerotiorum, which is involved in virulence, sclerotial development, and osmotic stress response. The expression of SsZNC1 was significantly up-regulated in the early stages of S. sclerotiorum infection on Arabidopsis leaves. The target deletion of SsZNC1 resulted in reduced virulence on Arabidopsis and oilseed rape. In addition, sclerotial development ability and growth ability under hyperosmotic conditions of SsZNC1 knockout transformants were reduced. A transcriptomic analysis unveiled its regulatory role in key cellular functions, including cellulose catabolic process, methyltransferase activity, and virulence, etc. Together, our results indicated that SsZNC1, a core regulatory gene involved in virulence, sclerotial development and stress response, provides new insight into the transcription regulation and pathogenesis of S. sclerotiorum. Full article

Restricted production of fungal secondary metabolites hinders the ability to conduct comprehensive research and development of novel biopesticides. Okaramine B from Penicillium demonstrates remarkable insecticidal efficacy; however, its biosynthetic yield is low, and its regulatory mechanism remains unknown. The present study found that the yield difference was influenced by fermentation modes in okaramine-producing strains and performed genomic and comparative transcriptome analysis of P. daleae strain NBP-49626, which exhibits significant features. The NBP-49626 genome is 37.4 Mb, and it encodes 10,131 protein-encoding genes. Up to 5097 differentially expressed genes (DEGs) were identified during the submerged and semi-solid fermentation processes. The oka gene cluster, lacking regulatory and transport genes, displayed distinct transcriptional patterns in response to the fermentation modes and yield of Okaramine B. Although transcription trends of most known global regulatory genes are inconsistent with those of oka, this study identified five potential regulatory genes, including two novel Zn(II)2Cys6 transcription factors, Reg2 and Reg19. A significant correlation was also observed between tryptophan metabolism and Okaramine B yields. In addition, several transporter genes were identified as DEGs. These results were confirmed using real-time quantitative PCR. This study provides comprehensive information regarding the regulatory mechanism of Okaramine B biosynthesis in Penicillium and is critical to the further yield improvement for the development of insecticides. Full article

Plant resource sharing mediated by mycorrhizal fungi has been a subject of recent debate, largely owing to the limitations of previously used isotopic tracking methods. Although CdSe/ZnS quantum dots (QDs) have been successfully used for in situ tracking of essential nutrients in plant-fungal systems, the Cd-containing QDs, due to the intrinsic toxic nature of Cd, are not a viable system for larger-scale in situ studies. We synthesized amino acid-based carbon quantum dots (CQDs; average hydrodynamic size 6 ± 3 nm, zeta potential −19 ± 12 mV) and compared their toxicity and uptake with commercial CdSe/ZnS QDs that we conjugated with the amino acid cysteine (Cys) (average hydrodynamic size 308 ± 150 nm, zeta potential −65 ± 4 mV) using yeast Saccharomyces cerevisiae as a proxy for mycorrhizal fungi. We showed that the CQDs readily entered yeast cells and were non-toxic up to 100 mg/L. While the Cys-conjugated CdSe/ZnS QDs were also not toxic to yeast cells up to 100 mg/L, they were not taken up into the cells but remained on the cell surfaces. These findings suggest that CQDs may be a suitable tool for molecular tracking in fungi (incl. mychorrhizal fungi) due to their ability to enter fungal cells. Full article

Asperpyridone A represents an unusual class of pyridone alkaloids with demonstrated potential for hypoglycemic activity, primarily by promoting glucose consumption in HepG2 cells. Trichodin A, initially isolated from the marine fungus Trichoderma sp. strain MF106, exhibits notable antibiotic activities against Staphylococcus epidermidis. Despite their pharmacological significance, the regulatory mechanisms governing their biosynthesis have remained elusive. In this investigation, we initiated the activation of a latent gene cluster, denoted as “top”, through the overexpression of the Zn₂Cys₆ transcription factor TopC in Tolypocladium ophioglossoides. The activation of the top cluster led to the biosynthesis of asperpyridone A, pyridoxatin, and trichodin A. Our study also elucidated that the regulator TopC exerts precise control over the biosynthesis of asperpyridone A and trichodin A through the detection of protein–nucleic acid interactions. Moreover, by complementing these findings with gene deletions involving topA and topH, we proposed a comprehensive biosynthesis pathway for asperpyridone A and trichodin A in T. ophioglossoides. Full article