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Toxins Nov 2022Aflatoxin contamination in corn is a significant issue, posing substantial health threats to humans and animals. Aflatoxin testing protects consumer health, ensures the... (Review)
Review
Aflatoxin contamination in corn is a significant issue, posing substantial health threats to humans and animals. Aflatoxin testing protects consumer health, ensures the safe global trade of corn, and verifies compliance with legislation; however, effective sampling procedures are essential to ensure reliable results. While many sampling procedures exist, there is no evidence to indicate which is the best approach to ensure accurate detection. Using scientific and gray literature sources, this review analyzed sampling procedures to determine an optimum approach to guide the development of standard practices. Results revealed that sampling is the major source of error in the accurate assessment of aflatoxin levels in food and crucial for obtaining reliable results. To guarantee low variability and sample bias-increased sample size and sampling frequency, the use of automatic dynamic sampling techniques, adequate storage, and homogenization of aggregate samples for analysis are advised to ensure a representative sample. However, there is a lack of evidence to support this or indicate the current utilization of the reviewed procedures. Inadequate data prevented the recommendation of sample sizes or frequency for optimum practice, and thus, further research is required. There is an urgent need to make sampling procedures fit-for-purpose to obtain accurate and reliable aflatoxin measurements.
Topics: Humans; Animals; Aflatoxins; Zea mays; Research Design; Food; Food Contamination
PubMed: 36548716
DOI: 10.3390/toxins14120819 -
Scientific Reports Jan 2023We investigate laccase-mediated detoxification of aflatoxins, fungal carcinogenic food contaminants. Our experimental comparison between two aflatoxins with similar...
We investigate laccase-mediated detoxification of aflatoxins, fungal carcinogenic food contaminants. Our experimental comparison between two aflatoxins with similar structures (AFB and AFG) shows significant differences in laccase-mediated detoxification. A multi-scale modeling approach (Docking, Molecular Dynamics, and Density Functional Theory) identifies the highly substrate-specific changes required to improve laccase detoxifying performance. We employ a large-scale density functional theory-based approach, involving more than 7000 atoms, to identify the amino acid residues that determine the affinity of laccase for aflatoxins. From this study we conclude: (1) AFB is more challenging to degrade, to the point of complete degradation stalling; (2) AFG is easier to degrade by laccase due to its lack of side products and favorable binding dynamics; and (3) ample opportunities to optimize laccase for aflatoxin degradation exist, especially via mutations leading to π-π stacking. This study identifies a way to optimize laccase for aflatoxin bioremediation and, more generally, contributes to the research efforts aimed at rational enzyme optimization.
Topics: Aflatoxins; Aflatoxin B1; Laccase; Molecular Dynamics Simulation; Food Contamination
PubMed: 36650163
DOI: 10.1038/s41598-023-27519-1 -
Microbiology Spectrum Feb 2023The filamentous fungus Aspergillus flavus causes devastating diseases not only to cash crops but also to humans by secreting a series of secondary metabolites called...
The filamentous fungus Aspergillus flavus causes devastating diseases not only to cash crops but also to humans by secreting a series of secondary metabolites called aflatoxins. In the cotranslational or posttranslational process, -myristoyltransferase (Nmt) is a crucial enzyme that catalyzes the myristate group from myristoyl-coenzyme A (myristoyl-CoA) to the N terminus or internal glycine residue of a protein by forming a covalent bond. Members of the Nmt family execute a diverse range of biological functions across a broad range of fungi. However, the underlying mechanism of AflNmt action in the A. flavus life cycle is unclear, particularly during the growth, development, and secondary metabolic synthesis stages. In the present study, was found to be essential for the development of spore and sclerotia, based on the regulation of the xylose-inducible promoter. AflNmt, located in the cytoplasm of A. flavus, is also involved in modulating aflatoxin (AFB1) in A. flavus, which has not previously been reported in Aspergillus spp. In addition, we purified, characterized, and crystallized the recombinant AflNmt protein (rAflNmt) from the Escherichia coli expression system. Interestingly, the crystal structure of rAlfNmt is moderately different from the models predicted by AlphaFold2 in the N-terminal region, indicating the limitations of machine-learning prediction. In conclusion, these results provide a molecular basis for the functional role of AflNmt in A. flavus and structural insights concerning protein prediction. As an opportunistic pathogen, A. flavus causes crop loss due to fungal growth and mycotoxin contamination. Investigating the role of virulence factors during infection and searching for novel drug targets have been popular scientific topics in the field of fungal control. Nmt has become a potential target in some organisms. However, whether Nmt is involved in the developmental stages of A. flavus and aflatoxin synthesis, and whether AlfNmt is an ideal target for structure-based drug design, remains unclear. This study systematically explored and identified the role of AlfNmt in the development of spore and sclerotia, especially in aflatoxin biosynthesis. Moreover, although there is not much difference between the AflNmt model predicted using the AlphaFold2 technique and the structure determined using the X-ray method, current AI prediction models may not be suitable for structure-based drug development. There is still room for further improvements in protein prediction.
Topics: Humans; Aspergillus flavus; Antifungal Agents; Aflatoxins; Acyltransferases; Fungal Proteins
PubMed: 36541770
DOI: 10.1128/spectrum.04212-22 -
Food Additives & Contaminants. Part A,... Feb 2020Previously a calcium bentonite clay (CB) has been shown to tightly bind aflatoxins , significantly reduce mortality and morbidity in animals, and decrease molecular...
Previously a calcium bentonite clay (CB) has been shown to tightly bind aflatoxins , significantly reduce mortality and morbidity in animals, and decrease molecular biomarkers of aflatoxin exposure in humans and animals. Extensive studies have shown that CB is safe for human and animal consumption. In further work, we have investigated a highly active sodium bentonite (SB) clay (SB-E) with enhanced aflatoxin sorption efficacy compared to CB and other clays. Computational models and isothermal analyses were used to characterise toxin/clay surface interactions, predict mechanisms of toxin sorption, and gain insight into: 1) surface capacities and affinities, and 2) thermodynamics and sites of toxin/surface interactions. We have also used a toxin-sensitive living organism () to confirm the safety and predict the efficacy of SB-E against aflatoxin toxicity. Compared to CB, SB-E had a higher capacity for aflatoxin B (AfB) at pH 2 and 6.5. Results from this work suggest that high capacity clays such as SB-E can be used as effective aflatoxin enterosorbents to decrease short-term exposures in humans and animals when included in food and/or water during extended droughts and outbreaks of aflatoxicosis.
Topics: Adsorption; Aflatoxins; Animals; Bentonite; Clay; Computer Simulation; Hydra; Toxicity Tests; Water
PubMed: 31790632
DOI: 10.1080/19440049.2019.1662493 -
BMJ Paediatrics Open Apr 2023Aflatoxin B1 (AFB1) is a carcinogen produced by and which grow on maize. Given the high prevalence of child stunting (ie, impaired growth) and other nutritional...
Assessment of aflatoxin exposure, growth faltering and the gut microbiome among children in rural Guatemala: protocol for an observational prospective cohort and bioreactor simulations.
INTRODUCTION
Aflatoxin B1 (AFB1) is a carcinogen produced by and which grow on maize. Given the high prevalence of child stunting (ie, impaired growth) and other nutritional disorders in low-income and middle-income countries, where maize is consumed, the role of aflatoxin exposure may be significant. Observational reports have demonstrated associations between aflatoxin exposure and impaired child growth; however, most have been cross-sectional and have not assessed seasonal variations in aflatoxin, food preparation and dynamic changes in growth. Biological mechanistic data on how aflatoxin may exert an impact on child growth is missing. This study incorporates a prospective cohort of children from rural Guatemala to assess (1) temporal associations between aflatoxin exposure and child growth and (2) possible mediation of the gut microbiome among aflatoxin exposure, inflammation and child growth.
METHODS AND ANALYSIS
We will prospectively evaluate aflatoxin exposure and height-for-age difference trajectories for 18 months in a cohort of 185 children aged 6-9 months at enrolment. We will assess aflatoxin exposure levels and biomarkers of gut and systemic inflammation. We will examine the faecal microbiome of each child and identify key species and metabolic pathways for differing AFB1 exposure levels and child growth trajectories. In parallel, we will use bioreactors, inoculated with faeces, to investigate the response of the gut microbiome to varying levels of AFB1 exposure. We will monitor key microbial metabolites and AFB1 biotransformation products to study nutrient metabolism and the impact of the gut microbiome on aflatoxin detoxification/metabolism. Finally, we will use path analysis to summarise the effect of aflatoxin exposure and the gut microbiome on child growth.
ETHICS AND DISSEMINATION
Ethics approval was obtained from Arizona State University Institutional Review Board (IRB; STUDY00016799) and Wuqu' Kawoq/Maya Health Alliance IRB (WK-2022-003). Findings will be disseminated in scientific presentations and peer-reviewed publications.
Topics: Child; Humans; Aflatoxin B1; Aflatoxins; Bioreactors; Cross-Sectional Studies; Gastrointestinal Microbiome; Guatemala; Inflammation; Prospective Studies; Zea mays; Observational Studies as Topic
PubMed: 37080609
DOI: 10.1136/bmjpo-2023-001960 -
Toxins Sep 2023Fungal infection and mycotoxin contamination are major hazards to the safe storage and distribution of foods and feeds consumed by humans and livestock. This study...
Fungal infection and mycotoxin contamination are major hazards to the safe storage and distribution of foods and feeds consumed by humans and livestock. This study investigated the antifungal and antiaflatoxigenic activities of massoia essential oil (MEO) and its major constituent, C10 massoia lactone (C10), against aflatoxin B (AFB)-producing ATCC 22546. Their antifungal activities were evaluated using a disc diffusion assay, agar dilution method, and a mycelial growth inhibition assay with the AFB analysis using liquid chromatography triple quadrupole mass spectrometry. MEO and C10 exhibited similar antifungal and antiaflatoxigenic activities against . C10 was a primary constituent in MEO and represented up to 45.1% of total peak areas analyzed by gas chromatography-mass spectrometry, indicating that C10 is a major compound contributing to the antifungal and antiaflatoxigenic activities of MEO. Interestingly, these two materials increased AFB production in by upregulating the expression of most genes related to AFB biosynthesis by 3- to 60-fold. Overall, MEO and C10 could be suitable candidates as natural preservatives to control fungal infection and mycotoxin contamination in foods and feeds as Generally Recognized As Safe (GRAS) in the Flavor and Extract Manufacturers Association of the United States (FEMA), and MEO is a more suitable substance than C10 because of its wider range of uses and higher allowed concentration than C10.
Topics: Humans; Aflatoxins; Aspergillus flavus; Antifungal Agents; Mycotoxins; Aflatoxin B1; Lactones
PubMed: 37755997
DOI: 10.3390/toxins15090571 -
Toxins Mar 2020Exposure to aflatoxin is considered to be one of the causes of hepatocellular carcinoma (HCC). With the development of bioinformation, we sought to reveal the occurrence...
Exposure to aflatoxin is considered to be one of the causes of hepatocellular carcinoma (HCC). With the development of bioinformation, we sought to reveal the occurrence and development of aflatoxin-induced HCC through data research. We identified differentially expressed genes (DEGs) of datasets GSE127791 (Aflatoxin-treated pluripotent stem cell derived human hepatocytes vs. controls) and GSE64041 (liver carcinoma with unknown cause vs. non-cancerous tissue) by GEO2R to find the common DEGs. Gene ontology (GO) and KEGG path enrichment analysis were used to annotate the function of DEGs. Hub genes were screened from identified DEGs by protein-protein interaction (PPI) network analysis. The prognostic value of hub genes in cancer databases were evaluated. We obtained 132 common DEGs and 11 hub genes. According to cluster analysis and protein co-expression networks, we screened out the key genes, histidine-rich glycoprotein (HRG) and phosphoenolpyruvate carboxykinase 2 (PCK2). Oncomine database and survival curve analysis showed that the decline in HRG and PCK2 expression in the development of HCC indicated poor prognosis. We speculated that the decreased expression of HRG and PCK2 after aflatoxin exposure to hepatocyte may be related to aflatoxin induced hepatocyte injury and carcinogenesis. In addition, the decreased expression of HRG and PCK2 in the occurrence and development of HCC suggests a poor prognosis of HCC.
Topics: Aflatoxins; Biomarkers, Tumor; Carcinoma, Hepatocellular; Computational Biology; Datasets as Topic; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Gene Ontology; Humans; Liver Neoplasms; Multigene Family; Protein Interaction Maps; Survival Analysis
PubMed: 32210020
DOI: 10.3390/toxins12030203 -
BMC Pediatrics Jun 2022The continued provision of safe food, free of aflatoxin remains a huge challenge in developing countries. Despite several favourable climatic conditions that facilitate...
BACKGROUND
The continued provision of safe food, free of aflatoxin remains a huge challenge in developing countries. Despite several favourable climatic conditions that facilitate aflatoxin contamination in Ethiopia, there is little information showing aflatoxin exposure in children. Therefore, this study assessed aflatoxin exposure among young children in Butajira district, South-Central Ethiopia.
METHODS
Community based cross-sectional study stratified by agro-ecology was employed in Health and Demographic Surveillance Site (HDSS) of Butajira. The study included 332 children aged 12-59 months and were selected by simple random sampling technique using the HDSS registration number as a sampling frame. We collected data on dietary practice and aflatoxin exposure. Aflatoxin M1 concentration in urine was measured by Enzyme-Linked Immunosorbent assay (ELISA). The data analysis was carried out using STATA.
RESULTS
Detectable urinary Aflatoxin M1 was found in 62.4% (95% CI: 56.9 - 67.5%) of the children at a level ranging from 0.15 to 0.4 ng/ml. Children living in lowland agro-ecological zone had [AOR = 2.11 (95% CI; 1.15, 3.88] odds of being exposed to aflatoxin as compared to children living in highland agro-ecological zone. Children at lower socio-economic status [AOR = 0.27 (95% CI; 0.14, 0.50] and medium socio-economic status [AOR = 0.47 (95% CI; 0.25, 0.87] had 73% and 53% lower odds of being exposed to aflatoxin as compared to children in the higher socio-economic status, respectively.
CONCLUSIONS
Aflatoxin exposure among young children was very high in South-Central Ethiopia. This high aflatoxin exposure might emphasize the need for aflatoxin exposure mitigation strategies in Ethiopia. Especially, raising awareness of the community towards aflatoxin exposure is very crucial. In addition, further research is required to assess long-term aflatoxin exposure and its association with child growth and development.
Topics: Aflatoxin M1; Aflatoxins; Child; Child, Preschool; Cross-Sectional Studies; Diet; Ethiopia; Humans
PubMed: 35655154
DOI: 10.1186/s12887-022-03389-w -
Public Health Nutrition Aug 2021We hypothesise that exposure to aflatoxins and fumonisins, measured in serum, alters protein synthesis, reducing serum protein and insulin-like growth factor 1 (IGF-1),...
OBJECTIVE
We hypothesise that exposure to aflatoxins and fumonisins, measured in serum, alters protein synthesis, reducing serum protein and insulin-like growth factor 1 (IGF-1), increasing inflammation and infection, leading to child's linear growth failure.
DESIGN
Children 6-35 months, stratified by baseline stunting, were subsampled from an intervention trial on quality protein maize consumption and evaluated at two time-points.
SETTING
Blood samples and anthropometric data were collected in the pre-harvest (August-September 2015) and post-harvest (February 2016) seasons in rural Ethiopia.
PARTICIPANTS
102 children (50 stunted and 52 non-stunted).
RESULTS
Proportions of children exposed to aflatoxin G1, aflatoxin G2 and aflatoxin M1 were higher in the pre-harvest (8, 33 and 7, respectively) compared to post-harvest season (4, 28 and 4, respectively). The proportion of children exposed to any aflatoxin was higher in the pre-harvest than post-harvest season (51 % v. 41 %). Fumonisin exposure ranged from 0 % to 11 %. In joint statistical tests, aflatoxin exposure was associated with serum biomarkers of inflammation (C-reactive protein, α-1-glycoprotein) and protein status (transthyretin, lysine, tryptophan), IGF-1 and linear growth (all P < 0·01). However, exposure to specific aflatoxins was not significantly associated with any biomarkers or outcomes (all P > 0·05).
CONCLUSIONS
Aflatoxin exposure among rural Ethiopian children was high, with large variation between seasons and individual aflatoxins. Fumonisin exposure was low. There was no clear association between aflatoxin exposure and protein status, inflammation or linear growth. A larger study may be needed to examine the potential biological interactions, and the assessment of aflatoxins in food is needed to determine sources of high exposure.
Topics: Aflatoxins; Child; Ethiopia; Food Contamination; Fumonisins; Humans; Longitudinal Studies
PubMed: 33517942
DOI: 10.1017/S1368980021000422 -
Toxins Jan 2023Hazelnuts represent a potential source of mycotoxins that pose a public health issue due to their increasing consumption as food ingredients worldwide. Hazelnuts... (Review)
Review
Hazelnuts represent a potential source of mycotoxins that pose a public health issue due to their increasing consumption as food ingredients worldwide. Hazelnuts contamination by mycotoxins may derive from fungal infections occurring during fruit development, or in postharvest. The present review considers the available data on mycotoxins detected in hazelnuts, on fungal species reported as infecting hazelnut fruit, and general analytical approaches adopted for mycotoxin investigation. Prompted by the European safety regulation concerning hazelnuts, many analytical methods have focused on the determination of levels of aflatoxin B1 (AFB1) and total aflatoxins. An overview of the available data shows that a multiplicity of fungal species and further mycotoxins have been detected in hazelnuts, including anthraquinones, cyclodepsipeptides, ochratoxins, sterigmatocystins, trichothecenes, and more. Hence, the importance is highlighted in developing suitable methods for the concurrent detection of a broad spectrum of these mycotoxins. Moreover, control strategies to be employed before and after harvest in the aim of controlling the fungal contamination, and in reducing or inactivating mycotoxins in hazelnuts, are discussed.
Topics: Mycotoxins; Corylus; Food Contamination; Aflatoxins; Aflatoxin B1
PubMed: 36828414
DOI: 10.3390/toxins15020099