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Medical Mycology Aug 2020Aspergillosis is a respiratory fungal disease of importance in captive marine birds. The aim of this study was to describe the occurrence of aspergillosis in...
Aspergillosis is a respiratory fungal disease of importance in captive marine birds. The aim of this study was to describe the occurrence of aspergillosis in Thalassarche melanophris during rehabilitation events and to identify the etiological agent. All the albatrosses that were received for rehabilitation and died within a 2-year period were included in the study. The proportionate mortality rate caused by aspergillosis was 21.4% (3/14). One of the etiological agents was Aspergillus flavus/oryzae lineage, and the other was A. fumigatus sensu stricto. Our study suggests that aspergillosis can act as a limiting factor in the rehabilitation of albatrosses.
Topics: Animals; Aspergillosis; Aspergillus flavus; Aspergillus fumigatus; Birds; Female; Male; Oceans and Seas
PubMed: 31782484
DOI: 10.1093/mmy/myz122 -
Cells Sep 2022is a representative fungal species in the section Flavi and has been used as a model system to gain insights into fungal development and toxin production. has several... (Review)
Review
is a representative fungal species in the section Flavi and has been used as a model system to gain insights into fungal development and toxin production. has several adverse effects on humans, including the production of the most carcinogenic mycotoxin aflatoxins and causing aspergillosis in immune-compromised patients. In addition, infection of crops results in economic losses due to yield loss and aflatoxin contamination. is a saprophytic fungus that disperses in the ecosystem mainly by producing asexual spores (conidia), which also provide long-term survival in the harsh environmental conditions. Conidia are composed of the rodlet layer, cell wall, and melanin and are produced from an asexual specialized structure called the conidiophore. The production of conidiophores is tightly regulated by various regulators, including the central regulatory cascade composed of BrlA-AbaA-WetA, the fungi-specific velvet regulators, upstream regulators, and developmental repressors. In this review, we summarize the findings of a series of recent studies related to asexual development in and provide insights for a better understanding of other fungal species in the section Flavi.
Topics: Aflatoxins; Aspergillus flavus; Ecosystem; Fungal Proteins; Gene Expression Regulation, Fungal; Humans; Melanins; Spores, Fungal
PubMed: 36139369
DOI: 10.3390/cells11182796 -
Fungal Genetics and Biology : FG & B Nov 2020The carcinogenic aflatoxins are a human health concern as well as an economic burden to corn, peanut and other crops grown within the United States and globally....
The carcinogenic aflatoxins are a human health concern as well as an economic burden to corn, peanut and other crops grown within the United States and globally. Aflatoxins are produced by fungi species in Aspergillus section Flavi, primarily Aspergillus flavus. Though previously thought of as only asexual, A. flavus has recently been found to undergo sexual reproduction both in laboratory crosses and in the field. To elucidate the consequences of genetic exchange through a single generation of the sexual cycle within A. flavus, we constructed genetic maps based on three mapping populations, each composed of the parental strains and approximately 70 F1 progeny. Genome-wide data using double digest Restriction Associated DNA sequencing identified 496, 811, and 576 significant polymorphisms differentiating parents across eight linkage groups; these polymorphisms served as markers. Average spacing between marker loci was 3.1, 2.1, and 3.5 map units and overall map length was 1504.4, 1669.2, and 2001.3 cM. Recombination was non-randomly distributed across chromosomes with an average rate of recombination of about 46.81 cM per Mbp. We showed inheritance of mitochondrial loci from the sclerotial (female) parent in crosses, whereas nuclear loci showed a 1:1 segregation ratio from both parents. The linkage map will be useful in QTL analyses to identify traits that increase sexual fertility in A. flavus and modulate aflatoxin production, both of which have significant implications for sustainable reduction of aflatoxin contamination using biological control agents.
Topics: Aflatoxins; Aspergillus flavus; Chromosome Mapping; Crops, Agricultural; Genetic Linkage; Genetic Variation; Genotype; Humans; Phenotype; Reproduction; Sequence Analysis, DNA; Zea mays
PubMed: 33059038
DOI: 10.1016/j.fgb.2020.103478 -
Applied Microbiology and Biotechnology Mar 2022The exploitation of plant volatile organic compounds as biofumigants to control postharvest decaying of agro-products has received considerable research attention. Our...
The exploitation of plant volatile organic compounds as biofumigants to control postharvest decaying of agro-products has received considerable research attention. Our previous study reported that 1-nonanol, the main constituent of cereal volatiles, can inhibit Aspergillus flavus growth and has the potential as a biofumigant to control the fungal spoilage of cereal grains. However, the antifungal mechanism of 1-nonanol against A. flavus is still unclear at the molecular level. In this study, the minimum inhibitory concentration and minimum fungicidal concentration of 1-nonanol against A. flavus spores were 2 and 4 μL/mL, respectively. Scanning electron microscopy revealed that the 1-nonanol can distort the morphology of A. flavus spore. Annexin V-FITC/PI double staining showed that 1-nonanol induced phosphatidylserine eversion and increased membrane permeability of A. flavus spores. Transcriptional profile analysis showed that 1-nonanol treatment mainly affected the expression of genes related to membrane damage, oxidative phosphorylation, blockage of DNA replication, and autophagy in A. flavus spores. Flow cytometry analysis showed that 1-nonanol treatment caused hyperpolarization of mitochondrial membrane potential and accumulation of reactive oxygen species in A. flavus spores. 4',6-diamidino-2-phenylindole staining showed that treatment with 1-nonanol destroyed the DNA. Biochemical analysis results confirmed that 1-nonanol exerted destructive effects on A. flavus spores by decreasing intracellular adenosine triphosphate content, reducing mitochondrial ATPase activity, accumulating hydrogen peroxide and superoxide anions, and increasing catalase and superoxide dismutase enzyme activities. This study provides new insights into the antifungal mechanisms of 1-nonanol against A. flavus. KEY POINTS: • 1-Nonanol treatment resulted in abnormal morphology of A. flavus spores. • 1-Nonanol affects the expression of key growth-related genes of A. flavus. • The apoptosis of A. favus spores were induced after exposed to 1-nonanol.
Topics: Antifungal Agents; Aspergillus flavus; Fatty Alcohols; Spores, Fungal; Transcriptome
PubMed: 35179628
DOI: 10.1007/s00253-022-11830-4 -
Comprehensive Reviews in Food Science... Nov 2020Filamentous fungi represent a rich source of extrolites, including secondary metabolites (SMs) comprising a great variety of astonishing structures and interesting... (Review)
Review
Filamentous fungi represent a rich source of extrolites, including secondary metabolites (SMs) comprising a great variety of astonishing structures and interesting bioactivities. State-of-the-art techniques in genome mining, genetic manipulation, and secondary metabolomics have enabled the scientific community to better elucidate and more deeply appreciate the genetic and biosynthetic chemical arsenal of these microorganisms. Aspergillus flavus is best known as a contaminant of food and feed commodities and a producer of the carcinogenic family of SMs, aflatoxins. This fungus produces many SMs including polyketides, ribosomal and nonribosomal peptides, terpenoids, and other hybrid molecules. This review will discuss the chemical diversity, biosynthetic pathways, and biological/ecological role of A. flavus SMs, as well as their significance concerning food safety and security.
Topics: Aflatoxins; Aspergillus flavus; Biosynthetic Pathways; Food Safety; Fungal Proteins; Genes, Fungal; Metabolome; Polyketides
PubMed: 33337039
DOI: 10.1111/1541-4337.12638 -
G3 (Bethesda, Md.) Aug 2021Aspergillus flavus is an opportunistic pathogen of crops, including peanuts and maize, and is the second leading cause of aspergillosis in immunocompromised patients. A....
Aspergillus flavus is an opportunistic pathogen of crops, including peanuts and maize, and is the second leading cause of aspergillosis in immunocompromised patients. A. flavus is also a major producer of the mycotoxin, aflatoxin, a potent carcinogen, which results in significant crop losses annually. The A. flavus isolate NRRL 3357 was originally isolated from peanut and has been used as a model organism for understanding the regulation and production of secondary metabolites, such as aflatoxin. A draft genome of NRRL 3357 was previously constructed, enabling the development of molecular tools and for understanding population biology of this particular species. Here, we describe an updated, near complete, telomere-to-telomere assembly and re-annotation of the eight chromosomes of A. flavus NRRL 3357 genome, accomplished via long-read PacBio and Oxford Nanopore technologies combined with Illumina short-read sequencing. A total of 13,715 protein-coding genes were predicted. Using RNA-seq data, a significant improvement was achieved in predicted 5' and 3' untranslated regions, which were incorporated into the new gene models.
Topics: Aflatoxins; Aspergillus flavus; Chromosomes; Genome, Fungal; Humans; Sequence Analysis, DNA
PubMed: 34849826
DOI: 10.1093/g3journal/jkab213 -
Toxins Jun 2023Peanut seeds are susceptible to infection, which has a severe impact on the peanut industry and human health. However, the molecular mechanism underlying this defense...
Peanut seeds are susceptible to infection, which has a severe impact on the peanut industry and human health. However, the molecular mechanism underlying this defense remains poorly understood. The aim of this study was to analyze the changes in differentially expressed genes (DEGs) and differential metabolites during infection between Zhonghua 6 and Yuanza 9102 by transcriptomic and metabolomic analysis. A total of 5768 DEGs were detected in the transcriptomic study. Further functional analysis showed that some DEGs were significantly enriched in pectinase catabolism, hydrogen peroxide decomposition and cell wall tissues of resistant varieties at the early stage of infection, while these genes were differentially enriched in the middle and late stages of infection in the nonresponsive variety Yuanza 9102. Some DEGs, such as those encoding transcription factors, disease course-related proteins, peroxidase (POD), chitinase and phenylalanine ammonialyase (PAL), were highly expressed in the infection stage. Metabolomic analysis yielded 349 differential metabolites. Resveratrol, cinnamic acid, coumaric acid, ferulic acid in phenylalanine metabolism and 13S-HPODE in the linolenic acid metabolism pathway play major and active roles in peanut resistance to A. flavus. Combined analysis of the differential metabolites and DEGs showed that they were mainly enriched in phenylpropane metabolism and the linolenic acid metabolism pathway. Transcriptomic and metabolomic analyses further confirmed that peanuts infected with activates various defense mechanisms, and the response to is more rapid in resistant materials. These results can be used to further elucidate the molecular mechanism of peanut resistance to infection and provide directions for early detection of infection and for breeding peanut varieties resistant to aflatoxin contamination.
Topics: Humans; Transcriptome; Aspergillus flavus; Arachis; alpha-Linolenic Acid; Plant Breeding; Aflatoxins; Seeds
PubMed: 37505683
DOI: 10.3390/toxins15070414 -
Journal of Agricultural and Food... May 2024contamination in agriculture and food industries poses threats to human health, leading to a requirement of a safe and effective method to control fungal contamination....
contamination in agriculture and food industries poses threats to human health, leading to a requirement of a safe and effective method to control fungal contamination. Chitosan-based nitrogen-containing derivatives have attracted much attention due to their safety and enhanced antimicrobial applications. Herein, a new benzimidazole-grafted chitosan (BAC) was synthesized by linking the chitosan (CS) with a simple benzimidazole compound, 2-benzimidazolepropionic acid (BA). The characterization of BAC was confirmed by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance spectroscopy (H and C NMR). Then, the efficiency of BAC against ACCC 32656 was investigated in terms of spore germination, mycelial growth, and aflatoxin production. BAC showed a much better antifungal effect than CS and BA. The minimum inhibitory concentration (MIC) value was 1.25 mg/mL for BAC, while the highest solubility of CS (16.0 mg/mL) or BA (4.0 mg/mL) could not completely inhibit the growth of . Furthermore, results showed that BAC inhibited spore germination and elongation by affecting ergosterol biosynthesis and the cell membrane integrity, leading to the permeabilization of the plasma membrane and leakage of intracellular content. The production of aflatoxin was also inhibited when treated with BAC. These findings indicate that benzimidazole-derived natural CS has the potential to be used as an ideal antifungal agent for food preservation.
Topics: Aspergillus flavus; Benzimidazoles; Chitosan; Fungicides, Industrial; Microbial Sensitivity Tests; Aflatoxins; Antifungal Agents; Spores, Fungal
PubMed: 38687832
DOI: 10.1021/acs.jafc.4c01010 -
Toxins Aug 2022Aflatoxin contamination poses serious health concerns to consumers of peanut and peanut products. This study aimed at investigating the response of peanuts to...
Aflatoxin contamination poses serious health concerns to consumers of peanut and peanut products. This study aimed at investigating the response of peanuts to Aspergillus flavus infection and aflatoxin accumulation. Isolates of A. flavus were characterised either as aflatoxigenic or non-aflatoxigenic using multiple cultural techniques. The selected isolates were used in an in vitro seed colonisation (IVSC) experiment on two A. flavus-resistant and susceptible peanut genotypes. Disease incidence, severity, and aflatoxin accumulation were measured. Genotypes differed significantly (p < 0.001) in terms of the incidence and severity of aflatoxigenic and non-aflatoxigenic A. flavus infection with the non-aflatoxigenic isolate having significantly higher incidence and severity values. There was no accumulation of aflatoxins in peanut genotypes inoculated with non-aflatoxigenic isolate, indicating its potential as a biocontrol agent. Inoculations with the aflatoxigenic isolate resulted in the accumulation of aflatoxin B1 and G1 in all the peanut genotypes. Aflatoxin B2 was not detected in ICGV−03401 (resistant genotype), while it was present and higher in Manipinta (susceptible genotype) than L027B (resistant genotype). ICGV−03401 can resist fungal infection and aflatoxin accumulation than L027B and Manipinta. Non-aflatoxigenic isolate detected in this study could further be investigated as a biocontrol agent.
Topics: Aflatoxin B1; Aflatoxins; Arachis; Aspergillus flavus; Genotype
PubMed: 36006198
DOI: 10.3390/toxins14080536 -
Toxins May 2023Aflatoxins are immunosuppressive and carcinogenic secondary metabolites, produced by the filamentous ascomycete , that are hazardous to animal and human health. In this...
Aflatoxins are immunosuppressive and carcinogenic secondary metabolites, produced by the filamentous ascomycete , that are hazardous to animal and human health. In this study, we show that multiplexed host-induced gene silencing (HIGS) of genes essential for fungal sporulation and aflatoxin production (, , , and confers enhanced resistance to infection and aflatoxin contamination in groundnut (<20 ppb). Comparative proteomic analysis of contrasting groundnut genotypes (WT and near-isogenic HIGS lines) supported a better understanding of the molecular processes underlying the induced resistance and identified several groundnut metabolites that might play a significant role in resistance to infection and aflatoxin contamination. Fungal differentiation and pathogenicity proteins, including calmodulin, transcriptional activator-HacA, kynurenine 3-monooxygenase 2, VeA, VelC, and several aflatoxin pathway biosynthetic enzymes, were downregulated in infecting the HIGS lines. Additionally, in the resistant HIGS lines, a number of host resistance proteins associated with fatty acid metabolism were strongly induced, including phosphatidylinositol phosphate kinase, lysophosphatidic acyltransferase-5, palmitoyl-monogalactosyldiacylglycerol Δ-7 desaturase, ceramide kinase-related protein, sphingolipid Δ-8 desaturase, and phospholipase-D. Combined, this knowledge can be used for groundnut pre-breeding and breeding programs to provide a safe and secure food supply.
Topics: Humans; Animals; Aspergillus flavus; Aflatoxins; Proteomics; Arachis; Plant Breeding; Aspergillosis; Gene Silencing
PubMed: 37235354
DOI: 10.3390/toxins15050319