-
Toxins Apr 2022Aflatoxin, a type of mycotoxin, is mostly produced by and It is responsible for the loss of billions of dollars to the world economy, by contaminating different crops... (Review)
Review
Aflatoxin, a type of mycotoxin, is mostly produced by and It is responsible for the loss of billions of dollars to the world economy, by contaminating different crops such as cotton, groundnut, maize, and chilies, and causing immense effects on the health of humans and animals. More than eighteen different types of aflatoxins have been reported to date, and among them, aflatoxins B1, B2, G1, and G2 are the most prevalent and lethal. Early detection of fungal infection plays a key role in the control of aflatoxin contamination. Therefore, different methods, including culture, chromatographic techniques, and molecular assays, are used to determine aflatoxin contamination in crops and food products. Many countries have set a maximum limit of aflatoxin contamination (2-20 ppb) in their food and agriculture commodities for human or animal consumption, and the use of different methods to combat this menace is essential. Fungal infection mostly takes place during the pre- and post-harvest stage of crops, and most of the methods to control aflatoxin are employed for the latter phase. Studies have shown that if correct measures are adopted during the crop development phase, aflatoxin contamination can be reduced by a significant level. Currently, the use of bio-pesticides is the intervention employed in many countries, whereby atoxigenic strains competitively reduce the burden of toxigenic strains in the field, thereby helping to mitigate this problem. This updated review on aflatoxins sheds light on the sources of contamination, and the on occurrence, impact, detection techniques, and management strategies, with a special emphasis on bio-pesticides to control aflatoxins.
Topics: Aflatoxins; Animals; Aspergillus flavus; Crops, Agricultural; Pesticides; Zea mays
PubMed: 35622554
DOI: 10.3390/toxins14050307 -
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 -
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 -
Frontiers in Microbiology 2023RNA interference (RNAi) is one of the important defense responses against viral infection, but its mechanism and impact remain unclear in mycovirus infections. In our...
RNA interference (RNAi) is one of the important defense responses against viral infection, but its mechanism and impact remain unclear in mycovirus infections. In our study, reverse genetics and virus-derived small RNA sequencing were used to show the antiviral responses of RNAi components in infected with Aspergillus flavus partitivirus 1 (AfPV1). qRT-PCR revealed that AfPV1 infection induced the expression of the RNAi components in compared with noninfected . Knock mutants of each RNAi component were generated, but the mutants did not exhibit any obvious phenotypic changes compared with the parental strain. However, after AfPV1 inoculation, production of AfPV1 was significantly less than in the parental strain. Furthermore, sporulation was greater in each AfPV1-infected mutant compared with the AfPV1-infected parental . We also investigated the sensitivity of virus-free and AfPV1-infected RNAi mutants and the parental strain to cell wall stress, osmotic stress, genotoxic stress, and oxidative stress. The mutants of DCLs and AGOs infected by AfPV1 displayed more changes than RDRP mutants in response to the first three stresses. Small RNA sequencing analysis suggested that AfPV1 infection reduced the number of unique reads of sRNA in , although there were many vsiRNA derived from the AfPV1 genome. GO term and KEGG pathway analyses revealed that the functions of sRNA affected by AfPV1 infection were closely related to vacuole production. These results provide a better understanding of the functional role of RNAi in the impact of AfPV1 on the hypovirulence of .
PubMed: 38033556
DOI: 10.3389/fmicb.2023.1252294 -
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 -
International Journal of Environmental... Oct 2020Crops contaminated by aflatoxins (AFs), the toxic and carcinogenic mycotoxins produced namely by and , have severe impacts on human health. Changes in temperature and... (Review)
Review
Crops contaminated by aflatoxins (AFs), the toxic and carcinogenic mycotoxins produced namely by and , have severe impacts on human health. Changes in temperature and water availability related to actual climate changes (increased temperature, heavy rainfalls, and droughts) are modulating factors of mould growth and production of mycotoxins. To protect human and animal health from the harmful effects caused by AFs, the development of a safe and effective multifaceted approach in combating food and feed contamination with AFs is necessary. This review aims to collect and analyze the available information regarding AF presence in food and feed to reinforce AF management and to prevent health issues related to the AF exposure in the light of actual climate changes.
Topics: Aflatoxins; Animals; Aspergillus; Aspergillus flavus; Climate Change; Food Contamination; Fungi; Humans
PubMed: 33120863
DOI: 10.3390/ijerph17217850 -
Toxins May 2021Aflatoxin B is a potent carcinogen produced by , mainly during grain storage. As pre-harvest methods are insufficient to avoid mycotoxin presence during storage, diverse...
Aflatoxin B is a potent carcinogen produced by , mainly during grain storage. As pre-harvest methods are insufficient to avoid mycotoxin presence during storage, diverse curative techniques are being investigated for the inhibition of fungal growth and aflatoxin detoxification. spp. represent an alternative as they are a promising source of detoxifying enzymes. Fifty-nine isolates and a strain from the commercial product Mycostop, evaluated against and ochratoxin A during previous work, were screened for their ability to inhibit growth and decrease the aflatoxin amount. The activities of bacterial cells and cell-free extracts (CFEs) from liquid cultures were also evaluated. Fifty-eight isolates were able to inhibit fungal growth during dual culture assays, with a maximal reduction going down to 13% of the control. Aflatoxin-specific production was decreased by all isolates to at least 54% of the control. CFEs were less effective in decreasing fungal growth (down to 40% and 55% for unheated and heated CFEs, respectively) and aflatoxin-specific production, with a few CFEs causing an overproduction of mycotoxins. Nearly all isolates were able to degrade AFB when growing in solid and liquid media. A total degradation of AFB was achieved by Mycostop on solid medium, as well as an almost complete degradation by IX20 in liquid medium (6% of the control). CFE maximal degradation went down to 37% of the control for isolate IX09. The search for degradation by-products indicated the presence of a few unknown molecules. The evaluation of residual toxicity of the tested isolates by the SOS chromotest indicated a detoxification of at least 68% of AFB's genotoxicity.
Topics: Aflatoxin B1; Aspergillus flavus; Carcinogens; Decontamination; Ochratoxins; Penicillium; Streptomyces
PubMed: 34066812
DOI: 10.3390/toxins13050340 -
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 -
Toxins Apr 2022Contamination of food chains by toxigenic fungi and aflatoxins is a global problem that causes damage to human health, as well as to crop and livestock production. The...
Contamination of food chains by toxigenic fungi and aflatoxins is a global problem that causes damage to human health, as well as to crop and livestock production. The objective is to evaluate and total aflatoxins (AFs) occurrence in totally mixed rations (TMRs) for dairy cows and aflatoxin M (AFM) in milk for human consumption. Ninety-nine dairy production units located in Aguascalientes, Mexico, were randomly selected, and samples were collected from TMRs, raw milk, and milk marketed in the city in two consecutive agricultural cycles. AFs were quantified in TMRs and milk by indirect enzyme immunoassay and HPLC; aflatoxigenic and molecular (PCR) capacity of monosporic isolates in the feed was characterized. All feed, raw, and pasteurized milk samples showed aflatoxin contamination (26.0 ± 0.4 µg/kg, 32.0 ± 1.0, and 31.3 ± 0.7 ng/L, respectively), and a significant proportion (90.4, 11.3, and 10.3%) exceeded the locally applied maximum permissible limits for feed and milk (20.0 µg/kg and 50 ng/L). Aflatoxin contamination in both TMRs and milk indicated a seasonal influence, with a higher concentration in the autumn-winter cycle when conditions of higher humidity prevail. The results obtained suggest the existence of contamination by aflatoxigenic and aflatoxins in the diet formulated for feeding dairy cows and, consequently, in the dairy food chain of this region of the Mexican Highland Plateau.
Topics: Aflatoxin M1; Aflatoxins; Animals; Aspergillus flavus; Cattle; Female; Mexico; Milk
PubMed: 35622539
DOI: 10.3390/toxins14050292 -
Polish Journal of Microbiology Dec 2022Aflatoxin (AF)-producing fungi such as commonly contaminate animal feeds, causing high economic losses. is the most prevalent and produces AFB1, a potent mutagen, and...
Aflatoxin (AF)-producing fungi such as commonly contaminate animal feeds, causing high economic losses. is the most prevalent and produces AFB1, a potent mutagen, and carcinogen threatening human and animal health. is a large group of closely related fungi sharing number of morphological and genetic similarities that complicate the diagnosis of highly pathogenic strains. We used here morphological and molecular assays to characterize fungal isolates from animal feeds in Southwestern Algeria. These tools helped to identify 20 out of 30 strains, and 15 of them belonged to the section . Further analyses detected four out of 15 as belonging to group. PCR targeting the AF genes' intergenic region amplified a single 674 bp amplicon in all four isolates. The amplicons were digested with a II endonuclease, and three specific fragments were observed for but lacked two typical fragments. Sequencing data of four amplicons confirmed the presence of the two II restriction sites yielding the three fragments, confirming that all four strains were . In addition, this analysis illustrated the genetic variability within the strains.
Topics: Animals; Humans; Aspergillus flavus; Aspergillus; Aflatoxins; Polymerase Chain Reaction; Animal Feed
PubMed: 36537059
DOI: 10.33073/pjm-2022-048