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International Journal of Food... Feb 2022This study assessed the levels of mycotoxins in maize from Kenyan households. Further, local open pollinated maize varieties were compared with commercial hybrids to...
This study assessed the levels of mycotoxins in maize from Kenyan households. Further, local open pollinated maize varieties were compared with commercial hybrids to evaluate which variety is less susceptible to mycotoxin contamination. Four hundred and eighty (n = 480) maize samples were collected in the years 2018-2020 from households in Eastern, Western, Coastal and Lake Victoria regions of Kenya. Liquid chromatography coupled to tandem mass spectrometry was used to detect and quantify 22 mycotoxins, along with 31 Aspergillus flavus metabolites in the samples. Eastern Kenya had the highest aflatoxin (AF) contamination with 75% of samples having AF levels above the Kenyan regulatory limits (10 μg/kg), the highest concentration was 558.1 μg/kg. In Western Kenya, only 18% of samples had concentration levels above the Kenyan regulatory limits for AF with highest sample having 73.3 μg/kg. The Lake Victoria region had the most fumonisins (F) contamination, with 53% of the samples having fumonisin B (FB) < 1000 μg/kg. However, only 20% of the samples surpassed the Kenyan regulatory limit for total fumonisins (2000 μg/kg) with the highest concentration being 13,022 μg/kg. In addition, 21.6% of samples from the Lake Victoria region had zearalenone (ZEN) and deoxynivalenol (DON) above regulatory limits for European countries (1000 μg/kg). Western region had the least A. flavus metabolites contamination (18%) while the Eastern region had the highest incidence of A. flavus metabolites (81%). Among the A. flavus metabolites, cyclopiazonic acid (CPA), beta-cyclopiazonic acid (β CPA), flavacol (FLV) and methylcitreo-isocoumarin (MIC) positively correlated with each other but negatively correlated with the other metabolites. Significant positive co-occurrence was also noted among Fusarium mycotoxins: nivalenol (NIV) positively correlated with DON (r = 0.81), fusarenon-X (FX) (r = 0.81) and ZEN (r = 0.70). Negative correlations were observed between Aspergillus and Fusarium mycotoxins: aflatoxin B (AFB) negatively correlated with FB (r = -0.11), FX (r = -0.17) and ZEN (r = -0.20). Local open-pollinated maize varieties (L-opv) were less susceptible to mycotoxin contamination compared to the commercial hybrids (C-hy). This study reveals that Kenyan maize is contaminated with multiple mycotoxins most of which are not regulated in Kenya despite being regulated in other parts of the world. A comprehensive legislation should therefore be put in place to protect the Kenyan public against chronic exposure to these mycotoxins. In addition to high yield, there is a need for commercial hybrid maize breeders to incorporate mycotoxin resistance as an important trait in germplasm improvement in seeds production.
Topics: Aspergillus flavus; Food Contamination; Kenya; Mycotoxins; Zea mays
PubMed: 34952410
DOI: 10.1016/j.ijfoodmicro.2021.109502 -
Veterinary Medicine and Science Jan 2023The ubiquitous environmental fungus Aspergillus flavus is also a life-threatening avian pathogen.
BACKGROUND
The ubiquitous environmental fungus Aspergillus flavus is also a life-threatening avian pathogen.
OBJECTIVES
This study aimed to assess the genetic diversity and population structure of A. flavus isolated from turkey lung biopsy or environmental samples collected in a poultry farm.
METHODS
A. flavus isolates were identified using both morphological and ITS sequence features. Multilocus microsatellite genotyping was performed by using a panel of six microsatellite markers. Population genetic indices were computed using FSTAT and STRUCTURE. A minimum-spanning tree (MST) and UPGMA dendrogram were drawn using BioNumerics and NTSYS-PC, respectively.
RESULTS
The 63 environmental (air, surfaces, eggshells and food) A. flavus isolates clustered in 36 genotypes (genotypic diversity = 0.57), and the 19 turkey lung biopsies isolates clustered in 17 genotypes (genotypic diversity = 0.89). The genetic structure of environmental and avian A. flavus populations were clearly differentiated, according to both F-statistics and Bayesian model-based analysis' results. The Bayesian approach indicated gene flow between both A. flavus populations. The MST illustrated the genetic structure of this A. flavus population split in nine clusters, including six singletons.
CONCLUSIONS
Our results highlight the distinct genetic structure of environmental and avian A. flavus populations, indicative of a genome-based adaptation of isolates involved in avian aspergillosis.
Topics: Animals; Aspergillus flavus; Bayes Theorem; Farms; Aspergillosis; Birds; Turkeys; Genetic Structures
PubMed: 36445341
DOI: 10.1002/vms3.1015 -
Mycotoxin Research Aug 2021Driven by increasing temperatures and the higher incidences of heat waves during summer, an increased incidence of Aspergillus flavus next to Fusarium verticillioides in...
Driven by increasing temperatures and the higher incidences of heat waves during summer, an increased incidence of Aspergillus flavus next to Fusarium verticillioides in European maize can be expected. In the current study, we investigated the interaction between both species. Colonies of A. flavus/F. verticillioides were grown in a single culture, in a dual culture, and in a mixed culture. The growth rate of A. flavus and F. verticillioides grown in a dual or mixed culture with the other species was clearly slower compared to the growth rate in a single culture. Mycotoxin production was in most cases negatively affected by dual or mixed inoculation. In planta, a dual inoculation resulted in reduced lesions of A. flavus, whereas the lesion size and toxin production of F. verticillioides were unaffected in the presence of A. flavus. The lesions as a result of a mixed inoculation were 112% bigger than a single A. flavus inoculation and 9% smaller than a single F. verticillioides inoculation. The fumonisin levels were 17% higher compared to a single inoculation. In case A. flavus was present two days before F. verticillioides, the lesion size of F. verticillioides was 55% smaller compared to a single F. verticillioides inoculation, and fumonisin production was almost completely inhibited. The interaction between A. flavus and F. verticillioides is highly dynamic and depends on the experimental conditions, on the variables measured and on the way they colonize the host, in two inoculation points, simultaneously in one inoculation point, or sequentially one species colonizing an existing lesion made by the other.
Topics: Aspergillus flavus; Fusarium; Microbial Interactions; Mycotoxins; Zea mays
PubMed: 34128190
DOI: 10.1007/s12550-021-00435-x -
Toxins May 2024The fungal cell wall serves as the primary interface between fungi and their external environment, providing protection and facilitating interactions with the...
The fungal cell wall serves as the primary interface between fungi and their external environment, providing protection and facilitating interactions with the surroundings. Chitin is a vital structural element in fungal cell wall. Chitin deacetylase (CDA) can transform chitin into chitosan through deacetylation, providing various biological functions across fungal species. Although this modification is widespread in fungi, the biological functions of CDA enzymes in remain largely unexplored. In this study, we aimed to investigate the biofunctions of the CDA family in . The genome contains six annotated putative chitin deacetylases. We constructed knockout strains targeting each member of the CDA family, including Δ, Δ, Δ, Δ, Δ, and Δ. Functional analyses revealed that the deletion of CDA family members neither significantly affects the chitin content nor exhibits the expected chitin deacetylation function in . However, the Δ strain displayed distinct phenotypic characteristics compared to the wild-type (WT), including an increased conidia count, decreased mycelium production, heightened aflatoxin production, and impaired seed colonization. Subcellular localization experiments indicated the cellular localization of CDA6 protein within the cell wall of filaments. Moreover, our findings highlight the significance of the CBD1 and CBD2 structural domains in mediating the functional role of the CDA6 protein. Overall, we analyzed the gene functions of CDA family in , which contribute to a deeper understanding of the mechanisms underlying aflatoxin contamination and lay the groundwork for potential biocontrol strategies targeting .
Topics: Aspergillus flavus; Amidohydrolases; Aflatoxins; Fungal Proteins; Chitin; Cell Wall
PubMed: 38787069
DOI: 10.3390/toxins16050217 -
Applied Biochemistry and Biotechnology Apr 2022Cell wall mannoprotein (MP1) gene of an aflatoxigenic strain of Aspergillus flavus, isolated from stored wheat grains, was cloned and sequenced. MP1 protein was...
Cell wall mannoprotein (MP1) gene of an aflatoxigenic strain of Aspergillus flavus, isolated from stored wheat grains, was cloned and sequenced. MP1 protein was expressed in E. coli in soluble form and purified. Polyclonal antibodies were raised against recombinant MP1 protein and inactivated spores of this fungus in rabbit and purified by ammonium sulphate precipitation, Protein A sepharose and antigen affinity chromatography. The minimum concentration of purified mycelial or spore proteins that could be detected by ELISA was determined as 100 ng using 2 µg of these antibodies. The anti-MP1 antibody was found more sensitive than anti-spore protein antibody. Western blot and immunofluorescence analysis showed reactivity of these antibodies to various proteins (30 to 200 kDa) distributed throughout the surface of mycelia and spore of A. flavus. Cross-reactivity of these antibodies was detected with fungi belonging to different Aspergillus, Rhizopus and Alternaria species out of fourteen different fungal species tested. In fungal contaminated wheat grains, these antibodies could detect presence of as low as 1 µg mycelia or 10 spores per gram of wheat grains using ELISA. The results suggest that the developed antibodies could be successfully applied for the detection of predominant fungal infestation in stored wheat grains.
Topics: Animals; Antibodies; Aspergillus; Aspergillus flavus; Escherichia coli; Rabbits; Spores; Triticum
PubMed: 35013922
DOI: 10.1007/s12010-021-03780-w -
International Journal of Food... Oct 2023This study evaluated the synergistic antifungal effects of vapor-phase natural agents against Aspergillus flavus with an aim to prevent fungal contamination in...
This study evaluated the synergistic antifungal effects of vapor-phase natural agents against Aspergillus flavus with an aim to prevent fungal contamination in agricultural products. Screening different combinations of natural antifungal vapor agents using the checkerboard assay revealed that the cinnamaldehyde and nonanal (S) blend could exert the strongest synergistic antifungal activities against A. flavus, with a minimum inhibitory concentration (MIC) of 0.03 μL/mL, which caused a 76 % decrease in fungal population compared to when each agent was used separately. Subsequent gas chromatography-mass spectrometry (GC/MS) analysis demonstrated that the cinnamaldehyde/nonanal combination was stable and no effects on their individual molecular structures. S at 2 × MIC completely inhibited the fungal conidia production and mycelial growth. The calcofluor white (CFW) and dichloro-dihydro-fluorescein diacetate (DCFH-DA) staining assays showed that S treatment could accelerate the destruction of cell wall integrity and accumulation of reactive oxygen species (ROS) in A. flavus. Moreover, pathogenicity assay indicated that in contrast to separate treatment with cinnamaldehyde or nonanal, S could cause a decrease in the production of A. flavus asexual spores and AFB1 on peanuts, which verified its potential synergistic activity against fungal propagation. In addition, S effectively preserves the organoleptic and nutritional properties of stored peanuts. Overall, our findings strongly indicated that the cinnamaldehyde/nonanal combination is a potentially significant antifungal agent against A. flavus contamination during the postharvest storage of peanuts.
Topics: Aspergillus flavus; Antifungal Agents; Aldehydes
PubMed: 37331114
DOI: 10.1016/j.ijfoodmicro.2023.110277 -
Infection due to Aspergillus flavus and Rhizopus oryzae complex in a patient with diabetes mellitus.Biomedica : Revista Del Instituto... Mar 2023Fungal sinusitis is a pathology that can occur in patients with diabetes mellitus and be associated with a hyperglycemic crisis. It is an aggressive entity with local...
Fungal sinusitis is a pathology that can occur in patients with diabetes mellitus and be associated with a hyperglycemic crisis. It is an aggressive entity with local complications that include involvement of the orbit or the central nervous system, and vascular involvement. Despite surgical and antifungal treatment, mortality raises up to 75%. We report the case of a female patient with a diagnosis of diabetic ketoacidosis and signs of unilateral ophthalmoplegia, which led to the study with magnetic resonance imaging of the central nervous system, finding signs of sinusitis, meningitis, and cerebritis. Initial microbiological studies were negative, and biomarkers such as serum galactomannan and Cryptococcus antigen were also negative. After surgical management and the identification of Aspergillus flavus and Rhizopus spp. in sinus tissue, the patient received treatment with posaconazole and after two months of follow-up she presented clinical improvement. Dual fungal infection and infection by A. flavus are uncommon and clinically relevant entities, with no cases previously reported in our country, therefore this corresponds to a case of clinical interest.
Topics: Humans; Rhizopus oryzae; Aspergillus flavus; Diabetes Mellitus; Retrospective Studies
PubMed: 37167471
DOI: 10.7705/biomedica.6358 -
Microbiology Spectrum Aug 2023A variety of essential oils and edible compounds have been widely recognized for their antifungal activity in recent years. In this study, we explored the antifungal...
A variety of essential oils and edible compounds have been widely recognized for their antifungal activity in recent years. In this study, we explored the antifungal activity of estragole from Pimenta racemosa against Aspergillus flavus and investigated the underlying mechanism of action. The results showed that estragole had significant antifungal activity against A. flavus, with a minimum inhibitory concentration of 0.5 μL/mL against spore germination. Additionally, estragole inhibited the biosynthesis of aflatoxin in a dose-dependent manner, and aflatoxin biosynthesis was significantly inhibited at 0.125 μL/mL. Pathogenicity assays showed that estragole had potential antifungal activity against A. flavus in peanut and corn grains by inhibiting conidia and aflatoxin production. Transcriptomic analysis showed that the differentially expressed genes (DEGs) were mainly related to oxidative stress, energy metabolism, and secondary metabolite synthesis following estragole treatment. Importantly, we experimentally verified reactive oxidative species accumulation following downregulation of antioxidant enzymes, including catalase, superoxide dismutase, and peroxidase. These results suggest that estragole inhibits the growth and aflatoxin biosynthesis of A. flavus by modulating intracellular redox homeostasis. These findings expand our knowledge on the antifungal activity and molecular mechanisms of estragole, and provide a basis for estragole as a potential agent against A. flavus contamination. Aspergillus flavus contaminates crops and produces aflatoxins, carcinogenic secondary metabolites which pose a serious threat to agricultural production and animal and human health. Currently, control of A. flavus growth and mycotoxin contamination mainly relies on antimicrobial chemicals, agents with side effects such as toxic residues and the emergence of resistance. With their safety, environmental friendliness, and high efficiency, essential oils and edible compounds have become promising antifungal agents to control growth and mycotoxin biosynthesis in hazardous filamentous fungi. In this study, we explored the antifungal activity of estragole from against A. flavus and investigated its underlying mechanism. The results demonstrated that estragole inhibits the growth and aflatoxin biosynthesis of A. flavus by modulating intracellular redox homeostasis.
Topics: Humans; Aspergillus flavus; Reactive Oxygen Species; Antifungal Agents; Aflatoxins; Oils, Volatile; Homeostasis
PubMed: 37289093
DOI: 10.1128/spectrum.01348-23 -
Journal of Applied Microbiology Aug 2022To investigate hand-dug well water used for drinking and domestic purposes in a rural community in Southwest Nigeria for water safety and fungal presence as well as to...
AIM
To investigate hand-dug well water used for drinking and domestic purposes in a rural community in Southwest Nigeria for water safety and fungal presence as well as to determine the antifungal resistance and aflatoxigenic potentials of isolated fungi.
METHODS AND RESULTS
Water samples were analysed for risk of contamination, bacteriological and mycological parameters using a standard sanitary survey checklist and microbiological culturing. Isolates were identified and subjected to antifungal resistance profiling using the diffusion method for susceptibility testing of filamentous fungi. Multidrug-resistant strains were confirmed with DNA barcoding identification. Fungal isolates were screened for aflatoxigenic potentials by culture methods and confirmed by densitometric analysis. From the 23 hand-dug wells assessed, 56.52% had a high risk of contamination (ROC) score, nitrate >50 mg/L (73.9%), and the presence of total coliforms (100%), Escherichia coli (43.48%) and fungi (91.3%). Spearman rank correlation coefficient gave a positive and strong correlation between Total Fungi and Faecal Coliform (r = 0.701; p = 0.016; n = 23) at 0.05 significance level (2-tailed). Aspergillus sp. (34%), Penicillium sp. (18%) and Rhizopus sp. (17%) were the most dominant fungal genera. Isolates were resistant to fluconazole (76.19%), ketoconazole (73.80%), clotrimazole (92.86%), griseofulvin (88.09%) and nystatin (100%). Penicillium and Aspergillus (50%) were positive for cultural mycotoxin screening. A strain of antifungal-resistant A. flavus produced aflatoxin B1 (752 ppb) and B2 (15 ppb).
SIGNIFICANCE OF THE STUDY
The existence of antifungal-resistant and aflatoxigenic fungi in water used for drinking and domestic purposes shows that filamentous fungi constitute greater threats than previously recognized and this call for a paradigm shift from the perceived safety of untreated hand-dug well-water.
Topics: Aflatoxins; Antifungal Agents; Aspergillus; Aspergillus flavus; Fungi; Penicillium; Water
PubMed: 35368141
DOI: 10.1111/jam.15559 -
Scientific Reports May 2024Heavy metal accumulation is one of the major agronomic challenges that has seriously threatened food safety. As a result, metal-induced phytotoxicity concerns require...
Heavy metal accumulation is one of the major agronomic challenges that has seriously threatened food safety. As a result, metal-induced phytotoxicity concerns require quick and urgent action to retain and maintain the physiological activities of microorganisms, the nitrogen pool of soils, and the continuous yields of wheat in a constantly worsening environment. The current study was conducted to evaluate the plant growth-promoting endophytic Aspergillus flavus AUMC 16,068 and its EPS for improvement of plant growth, phytoremediation capacity, and physiological consequences on wheat plants (Triticum aestivum) under lead stress. After 60 days of planting, the heading stage of wheat plants, data on growth metrics, physiological properties, minerals content, and lead content in wheat root, shoot, and grains were recorded. Results evoked that lead pollution reduced wheat plants' physiological traits as well as growth at all lead stress concentrations; however, inoculation with lead tolerant endophytic A. flavus AUMC 16,068 and its respective EPS alleviated the detrimental impact of lead on the plants and promoted the growth and physiological characteristics of wheat in lead-contaminated conditions and also lowering oxidative stress through decreasing (CAT, POD, and MDA), in contrast to plants growing in the un-inoculated lead polluted dealings. In conclusion, endophytic A. flavus AUMC 16,068 spores and its EPS are regarded as eco-friendly, safe, and powerful inducers of wheat plants versus contamination with heavy metals, with a view of protecting plant, soil, and human health.
Topics: Triticum; Lead; Aspergillus flavus; Endophytes; Stress, Physiological; Polysaccharides; Biodegradation, Environmental; Soil Pollutants; Oxidative Stress; Plant Roots
PubMed: 38796501
DOI: 10.1038/s41598-024-61936-0