-
Mycotoxin Research Apr 2024Aspergillus section Flavi (Flavi) is a diverse group of fungal species whose common members include A. flavus and A. parasiticus. These are well-known for the production...
Aspergillus section Flavi (Flavi) is a diverse group of fungal species whose common members include A. flavus and A. parasiticus. These are well-known for the production of aflatoxin (AF) B and G and other toxic metabolites, like cyclopiazonic acid (CPA). They are saprophytic soil dwellers and also become crop opportunistic epiphytes. The consequence is contamination of the crop with mycotoxins, such as carcinogenic AF. We investigated the Flavi community structure of maize and that of their surrounding soil, including their mycotoxigenicity. Furthermore, we investigated the link of the maize Flavi diversity with preharvest maize AF levels. The study was carried out in four selected districts of Zambia, in a low rainfall zone. The Flavi characterisation was triphasic, involving morphological (colony colour and sclerotia formation), metabolic (AF and CPA production) and genetic (calmodulin gene polymorphism) analyses. Flavi abundance was determined by dilution plate technique on modified rose Bengal agar. Results showed that Flavi communities on maize and in soil differed. Maize had a higher Flavi species diversity than soil. A. parasiticus dominated the soil community by frequency of field appearance (85%), while maize was dominated by A. minisclerotigenes (45%). CPA-producers with or without AF production dominated the maize (65%) while producers of only AF (B/G) dominated the soil (88%). The ratio between maize A. parasiticus and A. minisclerotigenes abundance seemed to have had a bearing on the levels of AF in maize, with a ratio close to 1:1 having higher levels than a pure community of either A. parasiticus or A. minisclerotigenes.
PubMed: 38647834
DOI: 10.1007/s12550-024-00532-7 -
International Journal of Food... Jun 2024Previous investigations proved the potential of Saccharomyces cerevisiae MBELGA62 and Pichia kudriavzevii MBELGA61 as suitable biocontrolling agents against Aspergillus...
Previous investigations proved the potential of Saccharomyces cerevisiae MBELGA62 and Pichia kudriavzevii MBELGA61 as suitable biocontrolling agents against Aspergillus sp. through the production of soluble and volatile bioactive antifungal compounds. The present study delves into those finding by means of the identification of the volatile compounds produced by brewer's strains that demonstrated fungistatic and fungicidal effects against Aspergillus flavus and A. parasiticus when cultured in brewer's wort agar plates. Traditional brewer's yeasts such as S. cerevisiae MBELGA62 and Saccharomyces pastorianus SAFS235 synthetize volatiles that fully inhibited mycelial development for up to 9 days at 30 °C. The non-conventional brewer's strains P. kudriavzevii MBELGA61 and Meyerozyma guilliermondii MUS122 increased the lag phase by >100% and significantly reduced the fungal growth rate by 27.5-43.0% and 15.4-31.4%, respectively. In this context, 2-phenylethanol, 2-phenylethyl acetate and benzyl alcohol were identified as the main antifungal agents involved in Aspergillus sp.'s inhibition.
Topics: Aspergillus; Fermentation; Antifungal Agents; Volatile Organic Compounds; Saccharomyces cerevisiae; Pichia; Phenylethyl Alcohol
PubMed: 38640817
DOI: 10.1016/j.ijfoodmicro.2024.110692 -
Food Microbiology Aug 2024Aspergillus flavus colonization on agricultural products during preharvest and postharvest results in tremendous economic losses. Inspired by the synergistic antifungal...
Aspergillus flavus colonization on agricultural products during preharvest and postharvest results in tremendous economic losses. Inspired by the synergistic antifungal effects of essential oils, the aims of this study were to explore the mechanism of combined cinnamaldehyde and nonanal (S) against A. flavus and to evaluate the antifungal activity of S loading into diatomite (DM). Shriveled mycelia were observed by scanning electron microscopy, especially in the S treatment group. Calcofluor white staining, transmission electron microscopy, dichloro-dihydro-fluorescein diacetate staining and the inhibition of key enzymes in tricarboxylic acid cycle indicated that the antifungal mechanism of S against A. flavus was related to the cell wall damage, reactive oxygen species accumulation and energy metabolism interruption. RNA sequencing revealed that some genes involved in antioxidation were upregulated, whereas genes responsible for cell wall biosynthesis, oxidative stress, cell cycle and spore development were significantly downregulated, supporting the occurrence of cellular apoptosis. In addition, compared with the control group, conidia production in 1.5 mg/mL DM/cinnamaldehyde, DM/nonanal and DM/S groups were decreased by 27.16%, 48.22% and 76.66%, respectively, and the aflatoxin B1 (AFB1) contents decreased by 2.00%, 73.02% and 84.15%, respectively. These finding suggest that DM/S complex has potential uses in food preservation.
Topics: Aspergillus flavus; Antifungal Agents; Aflatoxin B1; Food Preservation; Acrolein; Aldehydes
PubMed: 38637086
DOI: 10.1016/j.fm.2024.104524 -
Journal of Agricultural and Food... May 2024Aflatoxins (AFs), highly carcinogenic natural products, are produced by the secondary metabolism of fungi such as . Essential for the fungi to respond to environmental...
Aflatoxins (AFs), highly carcinogenic natural products, are produced by the secondary metabolism of fungi such as . Essential for the fungi to respond to environmental changes and aflatoxin synthesis, the pheromone mitogen-activated protein kinase (MAPK) is a potential regulator of aflatoxin biosynthesis. However, the mechanism by which pheromone MAPK regulates aflatoxin biosynthesis is not clear. Here, we showed Gal83, a new target of Fus3, and identified the pheromone Fus3-MAPK signaling pathway as a regulator of the Snf1/AMPK energy-sensing pathway modulating aflatoxins synthesis substrates. The screening for Fus3 target proteins identified the β subunit of Snf1/AMPK complexes using tandem affinity purification and multiomics. This subunit physically interacted with Fus3 both and and received phosphorylation from Fus3. Although the transcript levels of aflatoxin synthesis genes were not noticeably downregulated in both 83 and 3 deletion mutant strains, the levels of aflatoxin B and its synthesis substrates and gene expression levels of primary metabolizing enzymes were significantly reduced. This suggests that both the Fus3-MAPK and Snf1/AMPK pathways respond to energy signals. In conclusion, all the evidence unlocks a novel pathway of Fus3-MAPK to regulate AFs synthesis substrates by cross-talking with the Snf1/AMPK complexes.
Topics: Aspergillus flavus; Fungal Proteins; Mitogen-Activated Protein Kinases; Gene Expression Regulation, Fungal; Secondary Metabolism; Protein Serine-Threonine Kinases; AMP-Activated Protein Kinases; Phosphorylation; Aflatoxins; Protein Binding; Signal Transduction
PubMed: 38634532
DOI: 10.1021/acs.jafc.4c01229 -
Environmental Microbiology Reports Apr 2024Aspergillus flavus is the most frequently identified producer of aflatoxins. Non-aflatoxigenic members of the A. flavus L strains are used in various continents as...
Aspergillus flavus is the most frequently identified producer of aflatoxins. Non-aflatoxigenic members of the A. flavus L strains are used in various continents as active ingredients of bioprotectants directed at preventing aflatoxin contamination by competitive displacement of aflatoxin producers. The current research examined the genetic diversity of A. flavus L strain across southern Europe to gain insights into the population structure and evolution of this species and to evaluate the prevalence of genotypes closely related to MUCL54911, the active ingredient of AF-X1. A total of 2173L strain isolates recovered from maize collected across Greece, Spain, and Serbia in 2020 and 2021 were subjected to simple sequence repeat (SSR) genotyping. The analysis revealed high diversity within and among countries and dozens of haplotypes shared. Linkage disequilibrium analysis indicated asexual reproduction and clonal evolution of A. flavus L strain resident in Europe. Moreover, haplotypes closely related to MUCL54911 were found to belong to the same vegetative compatibility group (VCG) IT006 and were relatively common in all three countries. The results indicate that IT006 is endemic to southern Europe and may be utilized as an aflatoxin mitigation tool for maize across the region without concern for potential adverse impacts associated with the introduction of an exotic microorganism.
Topics: Aspergillus flavus; Aflatoxins; Zea mays; Greece; Spain; Serbia
PubMed: 38634243
DOI: 10.1111/1758-2229.13249 -
Cureus Mar 2024Knowing the spectrum, prevalence, and modes of diagnosis of pulmonary aspergillosis (PA) will be beneficial to clinicians for its early diagnosis and management. This...
Knowing the spectrum, prevalence, and modes of diagnosis of pulmonary aspergillosis (PA) will be beneficial to clinicians for its early diagnosis and management. This study aims to estimate the prevalence, spectrum, and role of serological tests and radiological findings in the diagnosis of PA. A total of 150 patients were suspected of having PA after obtaining relevant clinical history and radiological imaging. The patients were grouped into each spectrum of PA as invasive PA (IPA), chronic necrotizing PA (CNPA), aspergilloma, allergic bronchopulmonary aspergillosis (ABPA) based on predisposing factors, clinical and radiological findings, and the guidelines of the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG). Samples (bronchoalveolar lavage (BAL), sputum, blood) were collected from these patients and processed in a microbiology lab. BAL and sputum were subjected to microscopy by potassium hydroxide mount, calcofluor white mount, and culture. The serum was separated from blood by centrifugation and subjected to specific serological tests based on the spectrum of PA that the patient was suspected to have. For IPA, serum and BAL galactomannan antigen enzyme-linked immunosorbent assay (ELISA) was performed. For CNPA and aspergilloma, the anti- IgG antibody ELISA was performed. For ABPA, the tests performed were total immunoglobulin E (IgE) ELISA, -specific IgE ELISA, and anti- immunoglobulin G (IgG) antibody ELISA. After compiling the clinical, radiological, culture, and serological findings, patients were diagnosed to have a particular spectrum of PA. The prevalence of IPA was 1.4%, CNPA was 4%, ABPA was 3.2%, and aspergilloma was 2.9%. CNPA was the predominant spectrum of PA in our study. Culture positivity for species was seen the highest in aspergilloma patients, followed by IPA, ABPA, and CNPA patients. was the most common causative agent of PA, except for IPA for which was the most common causative. and were less the frequent causes of PA. A combination of radiological, microbiological, and serological tests along with clinical correlation is needed to confirm the diagnosis of PA.
PubMed: 38618367
DOI: 10.7759/cureus.56147 -
Environmental Research Jul 2024In the present work, the biomass of Aspergillus flavus (AF) was modified using magnetic nanoparticles MnFeO and metal-organic framework of ZIF-67, and its ability to...
In the present work, the biomass of Aspergillus flavus (AF) was modified using magnetic nanoparticles MnFeO and metal-organic framework of ZIF-67, and its ability to remove tetracycline antibiotic (TCH) was investigated. With the help of physicochemical tests, AF biomass modification with ZIF-67 and MnFeO magnetic nanoparticles was confirmed. Based on the BET value, AF-MnFeO-ZIF-67 (139.83 m/g) has a higher surface value than AF (0.786 m/g) and AF/MnFeO (17.504 m/g). Also, the magnetic saturation value revealed that the modified biomass can be isolated from the treated solution using a simple magnetic field. Maximum TCH elimination (99.04%) using AF-MnFeO-ZIF-67 was obtained at pH 7, adsorber mass of 1 g/L, adsorption time of 40 min, and TCH content of 10 mg/L. The thermodynamic study indicated that the TCH abatement using the desired composite is spontaneous and exothermic. The experimental results showed that the adsorption process is compatible with the pseudo-second-order kinetic and Freundlich model. The maximum adsorption capacity for AF, AF-MnFeO, and AF-MnFeO-ZIF-67 was quantified to be 9.75 mg/g, 25.59 mg/g, and 43.87 mg/g, respectively. The reusability of the desired adsorbers was examined in up to 8 steps. The outcomes showed that the adsorbers can be used several times in TCH elimination. The provided composite can remove TCH from hospital wastewater, so it can be suggested for use in water and wastewater treatment works.
Topics: Aspergillus flavus; Tetracycline; Water Pollutants, Chemical; Biomass; Adsorption; Anti-Bacterial Agents; Metal-Organic Frameworks; Ferric Compounds; Manganese Compounds; Kinetics; Magnetite Nanoparticles; Water Purification; Imidazoles; Zeolites
PubMed: 38615794
DOI: 10.1016/j.envres.2024.118931 -
International Journal of Molecular... Mar 2024species create major postharvest problems due to the food losses caused by their mere presence and the hazardous mycotoxins they produce, such as aflatoxin B1 (AFB1)...
species create major postharvest problems due to the food losses caused by their mere presence and the hazardous mycotoxins they produce, such as aflatoxin B1 (AFB1) and ochratoxin A (OTA). These mycotoxins are mainly produced by and , respectively. In this study, we developed a rapid detection method for the two aforementioned species based on loop-mediated isothermal amplification (LAMP). The primers were designed to target genes belonging to the mycotoxin clusters and for and , respectively. Result visualization was carried out in real time via the detection of fluorescent signals. The method developed showed high sensitivity and specificity, with detection limits of 0.3 and 0.03 pg/reaction of purified DNA of and , respectively. The assays were further implemented on inoculated nuts, including pistachios and almonds, after one-step crude DNA extraction. These tests revealed a detection level of 0.5 spore/g that shows the effectiveness of LAMP as a rapid method for detecting potentially toxigenic spp. directly in food. The validation of the assays included tests on a larger scale that further confirmed their sensitivity and specificity, as well as enabling the production of ready-to-use LAMP prototype kits. These kits are easy to use and aim to simplify the screening of food samples in order to monitor the presence of specific contaminations.
Topics: Aspergillus flavus; Nuts; Mycotoxins; DNA; Nucleic Acid Amplification Techniques; Molecular Diagnostic Techniques
PubMed: 38612622
DOI: 10.3390/ijms25073809 -
Molecules (Basel, Switzerland) Apr 2024The uses of natural compounds, such as essential oils (EOs), are limited due to their instability to light, oxygen and temperature, factors that affect their...
The uses of natural compounds, such as essential oils (EOs), are limited due to their instability to light, oxygen and temperature, factors that affect their application. Therefore, improving stability becomes necessary. The objective of this study was to prepare inclusion complexes of essential oil (LCEO) with β-cyclodextrin (β-CD) using physical mixing (PM), kneading (KN) and co-precipitation (CP) methods and to evaluate the efficiency of the complexes and their physicochemical properties using ATR-FTIR, FT-Raman, DSC and TG. The study also assessed cytotoxicity against human colorectal and cervical cancer cells and antifungal activity against and . The complexation efficiency results presented significant evidence of LCEO:β-CD inclusion complex formation, with KN (83%) and CP (73%) being the best methods used in this study. All tested LCEO:β-CD inclusion complexes exhibited toxicity to HT-29 cells. Although the cytotoxic effect was less pronounced in HeLa tumor cells, LCEO-KN was more active against Hela than non-tumor cells. LCEO-KN and LCEO-CP inclusion complexes were efficient against both toxigenic fungi, and . Therefore, the molecular inclusion of LCEO into β-CD was successful, as well as the preliminary biological results, evidencing that the β-CD inclusion process may be a viable alternative to facilitate and increase future applications of this EO as therapeutic medication, food additive and natural antifungal agent.
Topics: Humans; Female; Antifungal Agents; Litsea; Uterine Cervical Neoplasms; Aspergillus flavus; Food Additives
PubMed: 38611905
DOI: 10.3390/molecules29071626 -
Molecules (Basel, Switzerland) Mar 2024A fungal isolate PDB-B (accession number: MT774567.1), which could tolerate up to 500 mg/L of cypermethrin, was isolated from the lake sediments of Kulamangalam...
A fungal isolate PDB-B (accession number: MT774567.1), which could tolerate up to 500 mg/L of cypermethrin, was isolated from the lake sediments of Kulamangalam tropical lake, Madurai, and identified by internal transcribed spacer (ITS) sequencing followed by phylogenetic analysis. The biotransformation potential of the strain was compared with five other strains (A, J, UN2, M1 and SM108) as a consortium, which were tentatively identified as , , , , and , respectively. Batch culture and soil microcosm studies were conducted to explore biotransformation using plate-based enzymatic screening and GC-MS. A mycotransformation pathway was predicted based on a comparative analysis of the transformation products (TPs) obtained. The cytotoxicity assay revealed that the presence of (3-methylphenyl) methanol and isopropyl ether could be relevant to the high rate of lethality.
Topics: Lakes; Phylogeny; India; Aspergillus niger; Aspergillus; Pyrethrins
PubMed: 38611726
DOI: 10.3390/molecules29071446