Search Results (921)

Invasive infections caused by Aspergillus flavus are more common in tropical and subtropical countries. The emergence of azole resistance in A. flavus complicates the management of aspergillosis, as azoles are the first-line and empirical therapy. The aim of this study was to investigate the molecular mechanisms underlying azole resistance in A. flavus, focusing on the cyp51C gene. We screened 34 molecularly confirmed A. flavus isolates obtained from patients with invasive aspergillosis for cyp51C gene expression by real-time RT-qPCR and for mutations by PCR sequencing. Molecular modeling and docking studies were performed using SWISS-MODEL, SwissDock, and I-TASSER software. Susceptibility testing revealed that 14.71% and 8.82% of isolates were resistant to itraconazole and posaconazole, respectively, with 5.88% exhibiting cross-resistance. The mRNA expression of cyp51C was upregulated (>2.5-fold) in five of the six resistant strains (83.33%). Hyperexpression of cyp51C was significantly more frequent among resistant isolates than among susceptible isolates (Fisher’s exact test, p = 0.014). Sequencing identified ten point mutations, including six synonymous and four non-synonymous substitutions. The non-synonymous mutations M54T and S240A were detected in the protein sequences of both resistant and susceptible isolates. Notably, D254N and I285V were observed exclusively in resistant isolates and in susceptible isolates with itraconazole MICs near the epidemiological threshold. Homology modeling and 3D structure prediction of the mutated Cyp51C protein demonstrated interactions with itraconazole, posaconazole, and voriconazole. Importantly, I-TASSER analysis indicated that the I285V substitution is located near the itraconazole binding site. Simultaneous overexpression of the cyp51A, cyp51B and cyp51C genes was observed in 33.33% of resistant isolates. These findings suggest that multiple target genes and mechanisms may act concurrently to confer azole resistance in A. flavus. Overall, this study supports the hypothesis that azole resistance in A. flavus is multifactorial and highlights the potential value of combining mutation analysis, gene expression profiling, and structural modeling for improved molecular surveillance and antifungal resistance monitoring. Full article

Aflatoxins are carcinogenic secondary metabolites produced by Aspergillus flavus and Aspergillus parasiticus. These two fungi are ubiquitous in soil and are often found in agricultural fields. Four aflatoxin variants commonly found in infected crops are: AFB₁, AFB₂, AFG₁, and AFG₂. Aspergillus parasiticus can produce all aflatoxin variants, with A. flavus only able to produce the aflatoxin B variants. Production of aflatoxins typically occurs as pre-harvest contamination in the Australian peanut-growing regions of Queensland. This study analysed geographic variations in aflatoxin component variants using the HPLC method for the 2020–2024 season peanuts. Aflatoxin-G was found as most common aflatoxin variant across three of the four peanut-growing regions. This study also evaluated diversity of A. flavus and A. parasiticus across the four peanut-growing regions, using post-harvest soil samples from the 2023–2024 growing season. Aspergillus parasiticus was found to be most prevalent (97% isolates) across the regions, whereas A. flavus was least prevalent (3% isolates) and only found in the Tolga region. The North Burnett had no Aspergillus colonies identified from the soil samples in the current year of collection. The data suggests the aflatoxin G variant is most predominant in Australian peanuts and also that there is large variation between the growing regions for prevalence of Aspergillus species. Full article

An Aspergillus flavus outbreak strain dominated the indoor environment in a Danish hospital ward for eight years and subsequently multiple isogenic infections occurred. We investigated whether strain-specific traits were present to understand its prevalence and persistence. The outbreak strain was studied alongside comparator A. flavus isolates with respect to altered virulence that could enhance its pathogenic potential and secondary metabolism that could influence environmental persistence. Twenty-four isolates were examined for growth patterns on ten media and by secondary metabolite profiling using high-performance liquid chromatography with diode-array detection. Strain-specific virulence and other phenotypic traits were studied in vivo using Galleria mellonella and in vitro by culturing on specialised media. No indication of virulence alterations was observed in larvae. However, the outbreak strain exhibited a reproducible fingerprint phenotype with distinct morphological features and secondary metabolites. These included mycotoxins known to be harmful to humans and animals. Although this study found no evidence of increased virulence, identification of a distinct phenotypic profile could indicate adaptation or an intrinsic ecological background of the outbreak strain and possibly competitive traits via potentially bioactive secondary metabolites. Moreover, the production of several mycotoxins by this A. flavus strain raises concerns for both patients and staff. Further analyses of the strain’s ecology, toxic potential, virulence, and phylogeny in a global context could be studied in future experiments. Full article

The present study was conducted to study the effect of exposure time to ultraviolet-C (UV-C) radiation on seed germination, fungal suppression and seedling growth of three Egyptian rice cultivars, namely, Sakha 105, Sakha 108, and Giza 183. Experiments were carried out under controlled laboratory conditions. Rice seeds were exposed to UV-C radiation with a wavelength of 253.7 nm and intensity of 1960 µW cm² for 0 (control), 10, 20, 30, 40, 50, and 60 min. Initial seed health testing showed the presence of several seed-borne fungi, mainly Alternaria alternata, Rhizoctonia solani, and Fusarium verticillioides, in addition to Aspergillus niger and Aspergillus flavus. Results revealed that UV-C exposure time, rice cultivar and their interactions significantly (p < 0.05) affected germination percentage, reduction percentage of seed fungal infection, and seedling growth parameters. The optimum exposure time was 30 min, which was found to maximize germination and improve shoot and root growth to achieve high levels of fungal suppression. Giza 183 exhibited the highest average germination percentage (92.40%), while Sakha 105 obtained the highest shoot height (17.00 cm) and root length (12.91 cm). The results indicate that UV-C irradiation is an effective, residue-free and environmentally sustainable seed treatment technology for improving rice seed quality as well as early seedling performance. Full article

Ants, plants, and hemipterans in tritrophic mutualisms represent closer approximations to real ecosystems compared to twofold mutualisms, playing a critical role in ecosystem functioning. Although habitat degradation is a useful framework for investigating the stability of mutualisms, few studies have focused on such mutualistic interactions in degraded grassland. In this study, we conducted both a field and a greenhouse experiment to assess the effect of grassland degradation on the organization of ant–plant networks and ant-hemipteran-plant tritrophic interactions in the light and severely degraded grassland of Songnen Plain, China. In general, we found that severe degradation of grassland changed the spatial distribution pattern of ant–plant networks from uniform to aggregation and increased the species diversity within these networks and facilitated the Lasius flavus-aphid/mealybugs-Artemisia scoparia tritrophic mutualisms. L. flavus improves individual plant performance by increasing plant height, reducing soil moisture content, and facilitating seed transportation of A. scoparia. These advantages enhance plant fitness and population spread of A. scoparia, consequently boosting its dominance within degraded grassland habitats. In turn, the well-developed root of A. scoparia attracted more L. flavus and aphid/mealybugs by providing living space and food. Our findings enhance the understanding of tritrophic mutualisms and their mechanisms in the context of grassland degradation, thus providing valuable information for the conservation, management, and restoration of degraded grassland. Full article

Bacterial–fungal interactions are prevalent in microbial communities, and fungi often facilitate bacterial dispersal along networks created by fungal hyphae. Using a microfluidic device, we examined how diverse bacterial species disperse in monoculture versus travel in coculture with Aspergillus flavus. Most of the bacteria traveled further when in coculture, although this was not absolute. Two bacteria showing significant dispersal rates only in coculture were the human pathogens Listeria monocytogenes and Staphylococcus aureus. Mechanistically, L. monocytogenes dispersal required flagella, with dispersal impaired in flagellar mutants but enhanced in ∆mogR strains that upregulate flagellar expression. In contrast, the non-flagellar bacterium S. aureus exhibited a unique, wave-like dispersal pattern along the hyphae, a phenomenon that was abolished in agr quorum-sensing mutants deficient in phenol-soluble modulins (PSMs). In a triculture of L. monocytogenes, S. aureus, and A. flavus, L. monocytogenes limited S. aureus dispersal along the fungal hyphae; however, this inhibition was dependent on an intact L. monocytogenes quorum system. Our findings reveal that bacterial motility on fungal networks arises from diverse, species-specific mechanisms, including flagella, transcriptional regulation, potential quorum-sensing-mediated interactions, as well as other notable dispersal phenomena that warrant further investigation. Full article

This study explores the use of endophytic fungi for the biocontrol of harmful aflatoxins (AFTs) in maize (Zea mays L.). The main objective of this study was to evaluate the effects of fungal pathogens and biocontrol agents on the corn seed germination and growth of seedlings under controlled conditions. Experiments were conducted under laboratory conditions in a growth chamber and in a greenhouse to assess the influence of environmental factors on seed performance and treatment efficacy. The growth chamber provided uniform conditions for physiological assessment while the greenhouses represented more realistic field conditions. Corn kernels were sown in sterile pots inside the growth chamber at standard conditions or in the greenhouse at controlled conditions and four treatment groups were established: untreated control seeds, seeds treated with non-AFT-producing (non-aflatoxigenic) strains (Trichoderma harzianum, T. asperellum and Aspergillus niger), seeds inoculated with AFT-producing (aflatoxigenic) strains (A. flavus and A. parasiticus), and seeds co-inoculated with both aflatoxigenic and non-aflatoxigenic strains (A. flavus and A. parasiticus with T. harzianum, T. asperellum or A. niger). High-performance liquid chromatography was utilized to detect and analyze the presence of AFTs. Co-culturing of A. flavus with T. harzianum resulted in a significant decrease in AFT levels, achieving a relative reduction of 99.3% compared to aflatoxigenic treatments alone. Among the isolates tested, T. harzianum and T. asperellum were the most effective at lowering AFT production of the aflatoxigenic strains, reducing the 5120 ± 560 µg/kg AFT level produced by A. flavus alone to 50.1 ± 1.10 and 63.1 ± 3.1 µg/kg, respectively. A. flavus negatively affected germination and early growth, whereas T. harzianum significantly enhanced both parameters. This study demonstrates that non-aflatoxigenic Trichoderma isolates can effectively mitigate AFT contamination and improve seedling growth, highlighting their potential as effective. sustainable, and locally adopted biocontrol agents for Pakistan’s chronic AFT problem under diverse environmental conditions—an area with minimal prior research and high national relevance. Full article

Aflatoxin B1 (AFB1), a highly potent Group 1 human carcinogen produced by Aspergillus flavus (A. flavus), poses a significant contamination risk to corn silage, a threat that is further intensified by rising global temperatures. This study aimed to characterize the combined effects of temperature and co-inoculation with the lactic acid bacterium Limosilactobacillus fermentum (L. fermentum) on AFB1 production and the expression of key biosynthetic genes in A. flavus colonizing corn silage. Corn silage was incubated at 20 °C, 30 °C, and 37 °C with and without L. fermentum. Using qRT-PCR and HPLC, we found that elevated temperatures, particularly 37 °C, strongly induced the expression of the aflatoxin biosynthetic cluster, including the regulatory gene aflR and structural genes such as omtA and ordA. Co-inoculation with L. fermentum consistently reduced in the final AFB1 concentration by approximately 50–60% at all three temperatures. Molecular analysis revealed that this reduction was associated with transcriptional repression at 30 °C and 37 °C. L. fermentum consistently and markedly down-regulated the expression of aflR and all structural genes. A particularly pronounced suppression was observed for the late-pathway gene ordA at 30 °C. These findings provide molecular evidence supporting the incorporation of selected L. fermentum strains into silage inoculant formulations to mitigate the AFB1 risk under high-temperature conditions. Full article

Background: The clinical burden of pulmonary diseases associated with the genus Aspergillus is increasing, although diagnostic focus remains largely on A. fumigatus. This study evaluated the diagnostic value of testing for A. flavus and A. niger-specific IgG in patients with chronic respiratory conditions. Methods: A retrospective study was conducted on 274 subjects (156 with chronic respiratory diseases, Bronchiectasis, Hypersensitivity Pneumonitis [HP], and Interstitial Lung Disease [ILD] non-HP, and 67 healthy controls). Cut-off values were established at the 97.5th percentile of the control group: 30 mg/L for A. fumigatus, 13 mg/L for A. flavus, and 8 mg/L for A. niger. Results: Among 109 patients who tested negative for A. fumigatus, 49.5% showed positivity to at least one other species, preventing a significant diagnostic gap in exposure detection. Notably, 40.4% of these patients exhibited simultaneous positivity for both A. flavus and A. niger. In the HP subgroup, 100% of patients who were A. fumigatus-positive also showed concurrent positivity to the two other species. Furthermore, the Bronchiectasis group showed the highest rate of isolated A. flavus at 11.8%. Conclusions: Testing solely for A. fumigatus IgG leads to substantial underestimation of Aspergillus exposure. Integrating A. flavus and A. niger into diagnostic panels is essential for a comprehensive immunological assessment of fungal interaction, particularly in HP and ILD, where identifying specific antigenic exposure is crucial for managing chronic inflammation and preventing disease progression. Full article

Wild maize (teosinte) has been reported to be less susceptible to biotic and abiotic stresses than its modern relative, corn. The composition of the teosinte root microbiome may be linked to traits such as drought tolerance and pest resistance. Trichoderma spp. are ubiquitous saprotrophic fungi found in the plant rhizosphere, enhancing host plant growth and crop productivity while alleviating biotic and abiotic stresses. The present study identified ten Trichoderma fungal isolates associated with the rhizosphere microbiome of teosinte (Zea mays spp. mexicana) and performed in vitro screening to assess both their multi-trait plant growth-promoting activities and their biological control potential against the phytopathogens Aspergillus flavus and Fusarium verticillioides. Additionally, interaction tests were conducted to evaluate the phytostimulant effect of Trichoderma spp. on maize (Zea mays) seed germination. Taxonomic and phylogenetic analysis identified five different Trichoderma species: T. rifaii (TA and TH); T. azevedoi (TB and TI); T. afroharzianum (TE); T. hamatum (TF and TG); and Trichoderma sp. (aff. bannaense) (TC, TD, and TJ). Partial least squares discriminant analysis revealed the isolates TF, TG, and TJ to have the highest potential for use as biocontrol and biostimulant agents. The present study is the first to examine Trichoderma species associated with the teosinte microbiome, and the results suggest that Trichoderma isolates are a potential sustainable alternative for improving maize cultivation. Full article

The cell wall (CW) of Mucoromycota has a unique chitin/chitosan complex, unlike chitin/glucan complex in Ascomycota. Under cell wall stress (CWS), induced by azo dyes, ascomycetes increase the amount of CW chitin. This study analyzes the response of Mucor flavus to CWS, induced by Congo red and Calcofluor white. It was found that azo dyes significantly reduced the biomass yield and inhibited apical growth and branching but did not lead to an increase in the amount of CW chitin/chitosan, neutral polysacchrides and cytosol osmolytes. Non-bilayer phosphatidic acids and phosphatidylethanolamines dominated in the control membrane lipids, but the proportion of bilayer phosphatidylcholines did not exceed 5%. Under CWS, the proportion of phosphatidic acids increased, while the proportion of phosphatidylethanolamines decreased and the degree of unsaturation of phospholipids increased. Storage lipids in the control were represented by mono-, di- and triacylglycerides and free fatty acids. Under CWS, the proportion of diacylglycerides increased significantly, while the proportion of triacylglycerides decreased. Thus, the CWS response of M. flavus consisted of significant changes in growth and the composition of membrane and storage lipids, but the amount of CW chitin/chitosan and cytosol osmolytes did not increase, which is different from the response of ascomycetes. Full article

Aspergillosis encompasses a heterogeneous spectrum of diseases caused by filamentous fungi of the genus Aspergillus, ranging from allergic airway disorders and chronic pulmonary infection to rapidly progressive invasive disease. Aspergillus fumigatus is the predominant pathogen worldwide, although other species, including Aspergillus flavus, Aspergillus terreus and cryptic species, contribute to morbidity and may exhibit intrinsic or acquired antifungal resistance. Early and accurate laboratory diagnosis is essential for timely treatment, appropriate antifungal selection, and stewardship. Traditional culture remains foundational, enabling confirmation of viable organisms, species-level identification, and antifungal susceptibility testing, but sensitivity is limited and turnaround times are prolonged. Non-culture approaches—including galactomannan, β-D-glucan, lateral flow assays, PCR, and next-generation sequencing—enhance diagnostic sensitivity, facilitate early detection, and allow identification of resistance-associated mutations. Optimal diagnostic performance is achieved through integrated, multimodal strategies combining laboratory tests with clinical and radiological findings. In invasive disease, concurrent use of biomarkers and molecular assays improves specificity and positive predictive value, while in allergic bronchopulmonary aspergillosis, immunological markers remain central. Future directions include standardised molecular protocols, novel antigenic and host-based biomarkers, and cost-effective, risk-adapted diagnostic algorithms to refine detection, guide therapy, and improve patient outcomes. Full article

Salinity stress adversely affects plant growth, yield, and productivity. It requires an investigation of ameliorative techniques, for example, spraying synthesized nanoparticles such as zinc oxide nanoparticles (ZnOnps). This current research studied the impact of sodium chloride as a stressor (150 mM NaCl) and the application of ZnOnps (2 g L⁻¹) on some biochemical properties of maize (Zea mays) leaves. The experiment involved examining some mineral concentrations (Na, K, Mg, Zn, Cu, Mn), fatty acid profile, and the antimicrobial (antibacterial and antifungal) properties of aqueous and diethyl ether maize leaf extracts, supported by molecular docking studies of the 17 previously determined phenolic compounds against DNA gyrase and alpha-L-fucosidase enzymes. Applying ZnOnps markedly decreased sodium concentrations from 5.8 to 1.9 mg g⁻¹ dry weight (DW) and established ion balance. ZnOnps also reduced γ-linolenic acid levels to 60% under stress, returning them to normal (34%), while increasing palmitic acid to 30%. Determining the antimicrobial activities indicated that extracts from plants sprayed with ZnOnps exhibited enhanced antimicrobial activity, as evidenced by the lowest minimum inhibitory concentrations against bacterial and fungal strains, including Salmonella typhi and Aspergillus flavus. The computational molecular docking confirmed the antimicrobial findings, with the compound apigenin-7-glucoside, which exhibited the highest binding affinity scores for antibacterial (−7.4 kcal/mol), and the compound chlorogenic acid as antifungal (−7.2 kcal/mol) against the enzyme targets. Thus, ZnOnps can be considered an efficient strategy for mitigating salinity stress in maize plants while elevating the antimicrobial activity and stability of variant secondary compounds. Full article

The growing threat of antimicrobial resistance necessitates alternative strategies to conventional antibiotics. Insects represent a promising source of antimicrobial peptides (AMPs) due to their potent innate immune responses. In this study, we investigated the hemolymph peptide extracts from Hermetia illucens larvae as a bioresource of infection-induced AMPs. Larvae were challenged with Gram-negative (Escherichia coli) and Gram-positive (Micrococcus flavus) bacteria, and hemolymph-derived peptides were extracted and fractionated by RP-HPLC. Peptide fractions were screened in vitro by agar diffusion assay against a panel of pathogenic strains. While extracts from uninfected larvae were essentially inactive, fractions 9–13 from infected larvae showed broad-spectrum antibacterial activity, including against multidrug-resistant clinical isolates such as carbapenem-resistant Klebsiella pneumoniae, suggesting an inducible immune response. Fractions were further analyzed by SDS-PAGE and LC-MS/MS to identify candidate AMPs, while shotgun proteomics on unfractionated extracts enabled quantitative comparison among conditions. Proteomics raw data are available via ProteomeXchange Consortium, with the dataset identifier PXD071144. In silico prediction using ProP 1.0, APD3, and CAMP_R4 supported the antimicrobial potential of candidate peptides. Overall, our integrative approach demonstrates that bacterial infection induces a diverse and bioactive immunopeptidome in H. illucens, supporting its potential as a sustainable platform for the discovery of novel antimicrobial agents. Full article

In the present study, a series of isoxazole derivatives were severally evaluated for their antifungal activity against the yeast Candida albicans and molds such as Aspergillus niger, Aspergillus flavus, and Fusarium oxysporum. The results demonstrate that the isoxazole derivatives exhibit considerable antifungal potential, particularly isoxazole-sulfonate ester 4b (Ar= 4-(Cl)C₆H₄, Ar′= 4-(CH₃)C₆H₄), which was found to be active with significant inhibition zones; the diameters of the C. albicans and F. oxysporum samples were measured at 17.00 ± 0.00 mm and 14.00 ± 0.00 mm, respectively. Furthermore, compounds 4a (Ar= 4-(CH₃)C₆H₄, Ar′= 4-(CH₃)C₆H₄), 4c (Ar: 4-(Cl)C₆H₄, Ar′: 4-(NO₂)C₆H₄) and 4d (Ar: 4-(Cl)C₆H₄, Ar′: 3-(Cl)-2-(OCH₃)C₆H₃) demonstrated MIC and MFC values of 20 µg/mL against C. albicans. In addition, the anti-hemolytic activity of these derivatives was evaluated. Compounds 4a, 4e (Ar: 4-(Cl)C₆H₄, Ar′: 3,4-(OCH₃)₂C₆H₃) and aroylisoxazole 3a (Ar: 4-(CH₃)C₆H₄) demonstrated a high degree of anti-hemolytic activity (>99%) at all concentrations evaluated (10, 15, and 20 mg/mL). Molecular docking and molecular dynamics studies over 200 ns revealed protein–ligand complexes to have high affinity and stability, which agrees with the experimental results. The compounds 4d, 4e, and 3a have shown significant interaction with the target proteins of C. albicans, A. flavus, and F. oxysporum, respectively. The results have revealed that the major interaction sites are hydrogen bonding, hydrophobic interactions, and the presence of a water molecule, especially with key residues like TYR_84, ASP_120, SER_90, and THR_89. The crystal structure of compound 4a was also obtained. Full article