Flavus Isolates Research Articles

MOLECULAR TECHNIQUES FOR DETECTION OF AFLATOXIGENIC ASPERGILLUS FLAVUS AND DETERMINE THEIR AFLATOXIN IN PISTACHIOS.

The better approach to control the contamination of food by aflatoxin (AF), is identifying the fungal strains responsible for producing that toxin. To estimate the presence of aflatoxigenic fungi growth and AFs in pistachios, thirty two pistachios samples (8 fresh and 24 salt roasted) were collected from Sulaimani markets (Iraq).Rapid screening method for AFs production were utilized initially based on culture methods, the positive samples confirmed by polymerase chain reaction (PCR) that were applied using DNA extracted from the isolates of A. flavus targeting the genes (afR, aflP, aflD, and aflQ). For determination of AF production of those isolates, ELISA technique was applied. The results show, contamination of 20 (62.5%) samples of pistachios with fungi, among them A. flavus was the predominant. Ten (71.4% (of the A. flavus isolates were amplified the target genes by applying PCR, indicating their ability to produce AFs. Application of ELISA technique revealed AFs detection in 21(65.6%) samples of pistachios. The mean levels of AFs determined were 6.06 and 12.08 μg/kg in fresh and salt roasted samples respectively. 19 (59.4%) of pistachio samples were exceed the maximum allowable limit set by the European union of total AFs concentration .Strong correlation obtained between AFs gene expression with AFs production. However, to avoid false negative and false positive results, applying more than one diagnostic molecular technique were suggested.

Creating large chromosomal segment deletions in Aspergillus flavus by a dual CRISPR/Cas9 system: Deletion of gene clusters for production of aflatoxin, cyclopiazonic acid, and ustiloxin B

Aspergillus flavus produces hepatocarcinogenic aflatoxin that adversely impacts human and animal health and international trade. A promising means to manage preharvest aflatoxin contamination of crops is biological control, which employs non-aflatoxigenic A. flavus isolates possessing defective aflatoxin gene clusters to outcompete field toxigenic populations. However, these isolates often produce other toxic metabolites. The CRISPR/Cas9 technology has greatly advanced genome editing and gene functional studies. Its use in deleting large chromosomal segments of filamentous fungi is rarely reported. A system of dual CRISPR/Cas9 combined with a 60-nucleotide donor DNA that allowed removal of A. flavus gene clusters involved in production of harmful specialized metabolites was established. It efficiently deleted a 102-kb segment containing both aflatoxin and cyclopiazonic acid gene clusters from toxigenic A. flavus morphotypes, L-type and S-type. It further deleted the 27-kb ustiloxin B gene cluster of a resulting L-type mutant. Overall efficiencies of deletion ranged from 66.6 % to 85.6 % and efficiencies of deletions repaired by a single copy of donor DNA ranged from 50.5 % to 72.7 %. To determine the capacity of this technique, a pigment-screening setup based on absence of aspergillic acid gene cluster was devised. Chromosomal segments of 201 kb and 301 kb were deleted with efficiencies of 57.7 % to 69.2 %, respectively. This system used natural A. flavus isolates as recipients, eliminated a forced-recycling step to produce recipients for next round deletion, and generated maker-free deletants with sequences predefined by donor DNA. The research provides a method for creating genuine atoxigenic biocontrol strains friendly for field trial release.

Nosocomial transmission of Aspergillus flavus in a neonatal intensive care unit: Long-term persistence in environment and interest of MALDI-ToF mass-spectrometry coupled with convolutional neural network for rapid clone recognition.

Aspergillosis of the newborn remains a rare but severe disease. We report four cases of primary cutaneous Aspergillus flavus infections in premature newborns linked to incubators contamination by putative clonal strains. Our objective was to evaluate the ability of matrix-assisted laser desorption/ionisation time of flight (MALDI-TOF) coupled to convolutional neural network (CNN) for clone recognition in a context where only a very small number of strains are available for machine learning. Clinical and environmental A. flavus isolates (n=64) were studied, 15 were epidemiologically related to the four cases. All strains were typed using microsatellite length polymorphism. We found a common genotype for 9/15 related strains. The isolates of this common genotype were selected to obtain a training dataset (6 clonal isolates/25 non-clonal) and a test dataset (3 clonal isolates/31 non-clonal), and spectra were analysed with a simple CNN model. On the test dataset using CNN model, all 31 non-clonal isolates were correctly classified, 2/3 clonal isolates were unambiguously correctly classified, whereas the third strain was undetermined (i.e., the CNN model was unable to discriminate between GT8 and non-GT8). Clonal strains of A. flavus have persisted in the neonatal intensive care unit for several years. Indeed, two strains of A. flavus isolated from incubators in September 2007 are identical to the strain responsible for the second case that occurred 3 years later. MALDI-TOF is a promising tool for detecting clonal isolates of A. flavus using CNN even with a limited training set for limited cost and handling time.

Efficiency of Some Clays and Organic Materials on the Reduction of Aflatoxin B1 Produced from Isolates of the Fungus Aspergillus flavus Contaminating Corn Grains

The study was conducted to evaluate the effectiveness of certain types of clay minerals, activated charcoal made from common reed and date palm kernel, in reducing the levels of aflatoxin B1(AFB1) produced by Aspergillus flavus that contaminated corn grains in a liquid medium, Yeast Extract Sucrose (YES). The results showed the presence of nine species of fungal genera that contaminated corn grains, with the Aspergillus spp being the most predominant, accounting for 42%, followed by the Penicillium spp with 27%, and the Fusarium spp with a 21%. The genera Rhizopus spp, Mucor spp, and Cladosporium spp had a prevalence of 5%, 4%, and 1%, respectively. The results of the thin-layer chromatography (TLC) test, which was used to isolate A. flavus fungi from corn grains and detect the presence of AFB1, showed variations in their ability to produce AFB1. Seventy-five percent of the diagnosed A. flavus isolates showed the ability to produce AFB1. The results indicated that all types of minerals used in the study were effective in reducing the levels of AFB1 in liquid media. Top of Form Similarly, activated charcoal from common reed showed a high potential for AFB1 reduction, where the highest reduction percentage was 93.90% for the activated charcoal from fermented reed at a concentration of 30 mgml−1.

Exploration of aflatoxigenic potential and seed colonization of Aspergillus flavus in sunflower

Aflatoxin, a mycotoxin found commonly in maize, peanuts, and sunflower worldwide, is associated with liver cancer, acute toxicosis, and growth impairment in humans and animals. In India, sunflower seeds are a source of snacks, cooking oil, and animal feed. These seeds are a potential source of aflatoxin contamination. However, reports on aflatoxin contamination in sunflower seeds and cakes are scarce. The objective of the current study was to determine the potential of Aspergillus flavus and total aflatoxin concentrations in sunflower seeds and cakes from small-scale oil processors in Rohilkhand region of Uttar Pradesh. 126 cultures of Aspergillus flavus were obtained from sunflower kernels, which showed wide variation in their cultural characters. Colour of conidial heads being a stable character was used to divide them into four groups out of which two representative isolates each, based on minimum and maximum number of sclerotia cm-2 of the culture medium were selected. Aflatoxin production by an isolate had positive correlation with the sclerotia production. These results can help in identifying the potent of A. flavus isolates for aflatoxin production and developing proper management strategies. In summary, humans and animals are potentially at high risk of exposure to aflatoxins through sunflower seeds and cakes from micro-scale millers in India and location influences risk.

Drug-Resistant Aspergillus spp.: A Literature Review of Its Resistance Mechanisms and Its Prevalence in Europe.

Infections due to the Aspergillus species constitute an important challenge for human health. Invasive aspergillosis represents a life-threatening disease, mostly in patients with immune defects. Drugs used for fungal infections comprise amphotericin B, triazoles, and echinocandins. However, in the last decade, an increased emergence of azole-resistant Aspergillus strains has been reported, principally belonging to Aspergillus fumigatus species. Therefore, both the early diagnosis of aspergillosis and its epidemiological surveillance are very important to establish the correct antifungal therapy and to ensure a successful patient outcome. In this paper, a literature review is performed to analyze the prevalence of Aspergillus antifungal resistance in European countries. Amphotericin B resistance is observed in 2.6% and 10.8% of Aspergillus fumigatus isolates in Denmark and Greece, respectively. A prevalence of 84% of amphotericin B-resistant Aspergillus flavus isolates is reported in France, followed by 49.4%, 35.1%, 21.7%, and 20% in Spain, Portugal, Greece, and amphotericin B resistance of Aspergillus niger isolates is observed in Greece and Belgium with a prevalence of 75% and 12.8%, respectively. The prevalence of triazole resistance of Aspergillus fumigatus isolates, the most studied mold obtained from the included studies, is 0.3% in Austria, 1% in Greece, 1.2% in Switzerland, 2.1% in France, 3.9% in Portugal, 4.9% in Italy, 5.3% in Germany, 6.1% in Denmark, 7.4% in Spain, 8.3% in Belgium, 11% in the Netherlands, and 13.2% in the United Kingdom. The mechanism of resistance is mainly driven by the TR34/L98H mutation. In Europe, no in vivo resistance is reported for echinocandins. Future studies are needed to implement the knowledge on the spread of drug-resistant Aspergillus spp. with the aim of defining optimal treatment strategies.

Reconsidering the Co-Occurrence of Aspergillus flavus in Spanish Vineyards and Aflatoxins in Grapes

Aspergillus flavus is a xerophilic fungus whose geographical distribution is expected to change due to the current climate change scenario. Grapes are one of the most important crops worldwide, and it is essential to evaluate the risk posed by their contamination with potential mycotoxigenic species. Recently, a few reports have described A. flavus as an emerging contaminant in vineyards, which has led to a discussion on the need to legislate aflatoxin contents in grapes. Using a specific PCR assay, the occurrence of A. flavus was demonstrated in 43 out of 61 grape samples collected from Spanish vineyards. Considering the high incidence observed, the risk of the grapes becoming contaminated with aflatoxin was subsequently evaluated. Aspergillus flavus isolates from grapes can grow in grape-based media under a variety of environmental conditions, but they were unable to produce either aflatoxin B1 (AFB1) or aflatoxin B2 (AFB2) even though their ability to produce these toxins was confirmed in a permissive medium (CYA). These results confirm that climate change is affecting the distribution of mycotoxigenic fungi, thereby increasing the occurrence of A. flavus in vineyards, although the risk of the grapes becoming contaminated with aflatoxin needs to be reconsidered.

The Molecular Identification and Antifungal Susceptibility of Clinical Isolates of Aspergillus Section Flavi from Three French Hospitals.

(1) Background: Aspergillus flavus is a cosmopolitan mold with medical, veterinary, and agronomic concerns. Its morphological similarity to other cryptic species of the Flavi section requires molecular identification techniques that are not routinely performed. For clinical isolates of Aspergillus section Flavi, we present the molecular identification, susceptibility to six antifungal agents, and clinical context of source patients. (2) Methods: One hundred forty fungal clinical isolates were included in the study. These isolates, recovered over a 15-year period (2001-2015), were identified based on their morphological characteristics as belonging to section Flavi. After the subculture, sequencing of a part of the β-tubulin and calmodulin genes was performed, and resistance to azole antifungals was screened on agar plates containing itraconazole and voriconazole. Minimum inhibitory concentrations were determined for 120 isolates by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution method. (3) Results: Partial β-tubulin and calmodulin sequences analysis showed that 138/140 isolates were A. flavus sensu stricto, 1 isolate was A. parasiticus/sojae, and 1 was A. nomiae. Many of the isolates came from samples collected in the context of respiratory tract colonization. Among probable or proven aspergillosis, respiratory infections were the most frequent, followed by ENT infections. Antifungal susceptibility testing was available for isolates (n = 120, all A. flavus ss) from one hospital. The MIC range (geometric mean MIC) in mg/L was 0.5-8 (0.77), 0.5-8 (1.03), 0.125-2 (0.25), 0.03-2 (0.22), 0.25-8 (1.91), and 0.03-0.125 (0.061) for voriconazole, isavuconazole, itraconazole, posaconazole, amphotericin B, and caspofungin, respectively. Two (1.67%) isolates showed resistance to isavuconazole according to current EUCAST breakpoints with MICs at 8 mg/L for isavuconazole and voriconazole. One of these two isolates was also resistant to itraconazole with MIC at 2 mg/L. (4) Conclusions: The present characterization of a large collection of Aspergillus belonging to the Flavi section confirmed that A. flavus ss is the predominant species. It is mainly implicated in respiratory and ENT infections. The emergence of resistance highlights the need to perform susceptibility tests on section Flavi isolates.

The biodiversity of Aspergillus flavus in stored rice grain leads to a decrease in the overall aflatoxin B1 production in these species

Aspergillus flavus is a significant fungus that poses a threat to food safety by producing mycotoxins in various crops. In this study, A. flavus isolates were obtained from storage rice collected from seven provinces in southern China, and their AFB1 production, biosynthesis genes presence, and diversity were detected. Results showed that 56 out of the 81 A. flavus isolates produced detectable levels of AFB1, and 71 isolates (87.6 %) possessed aflR gene in their AF synthesis gene cluster, while only 41 isolates (50.6 %) had the ver-1 gene present. Genetic diversity analysis using inter-simple sequence repeats (ISSR) markers revealed seven main clusters among the isolates and the genetic similarity coefficients of 81 A. flavus isolates ranged from 0.53 to 1.00. Additionally, coculture assays were conducted using two toxigenic and two atoxigenic isolates from the same grain depot to investigate the effect of intraspecific inhibition on AFB1 production and to assess the AFB1 contamination risk of storage rice. The in situ results demonstrated that the atoxigenic isolates effectively inhibited the AFB1 contamination of toxigenic isolates. These findings provide insight into the genetic diversity of A. flavus isolates populations and highlight the potential food safety hazards of them in stored rice grain in China.

Screening of Aflatoxin Production by Aspergillus flavus Isolates from Petroleum-contaminated Soil

Fungi are eukaryotic, heterogeneous, unicellular to filamentous, spore-bearing, and chemoorganotrophic organisms which lack chlorophyll. This present study was carried out to isolate and identify fungi from petroleum-contaminated soil. Several fungal genera which included Rhizopus spp., Mucor spp., Penicillium spp., Rhizoctonia spp., Aspergillus spp., Alternaria spp., and Cladosporiumspp. were isolated using potatoes dextrose agar, Czapek-Dox Agar, and Aspergillus flavus Differentiation Agar culture media that comparable with co-amoxiclav (1g) and chloramphenicol to prevent the growth of any bacteria. The direct plate and serial dilution agar plate methods were used for the isolation of fungi. Based on results, Aspergillusand Mucor spp. were the most predominant genera and had the highest number of colonies in the soil samples. In this investigation, seven out of 27 soil samples were morphologically (macroscopically and microscopically) identified, such as A. flavus. Aflatoxigenicity of A. flavus was detected using characteristics in Aspergillus differentiation agar and colony fluorescence on exposure to ultraviolet light. Moreover, molecular approaches were used for the detection of aflatoxigenic of the A. flavus isolates. Three structural (aflD, aflO, and aflP) and one regulatory (aflR) gene of the aflatoxin gene cluster of A. flavus were targeted for amplification by the polymerase chain reaction method. The aflatoxigenic of all six A. flavus isolates was detected molecularly which contained two structural (aflD, aflP)genes out of three structural genes, while there was no specific amplification of the aflO gene in the fourth, fifth, and sixth A. flavus which issimilar to the aflR gene in the first and second A. flavus.

Anti-fungal efficacy of combination of amphotericin B with colistin and gentamicin in McCarey-Kaufman corneal preservation medium.

To curtail the potential of donor corneal tissue disseminating fungi to the recipient's eye, we evaluated the addition of amphotericin B to McCarey-Kaufman (M-K)-corneal storage medium supplemented with colistin. Amphotericin B was examined for its ability to inhibit the growth of Candida albicans and Aspergillus flavus using a microbroth dilution test and checkerboard assay in combination with only gentamicin and a combination of colistin, gentamicin, and amphotericin B. The safety on epithelium and endothelium was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The minimal inhibitory concentration of gentamicin was found to be >256 μg/ml against both C. albicans and A. flavus, whereas that of amphotericin B was found to be in a range of 0.25-0.5 and 1-2 μg/ml for C. albicans and A. flavus, respectively. According to the checkerboard assay, 80% (4/5) of C. albicans isolates and 100% (5/5) of A. flavus isolates responded synergistically to the combination of amphotericin B and gentamicin, but only 20% (1/5) of C. albicans isolates showed an additive effect. None of the tested isolates displayed antagonism. The combined effect of the three drugs also did not display any antagonistic effect. Additionally, the MTT assay reveals no toxic effect of the antimicrobials used on corneal epithelial and endothelial cells. In vitro experiments demonstrate that amphotericin B is not toxic to either epithelium or endothelium and is a promising additive to the M-K medium supplemented with colistin.

The Effect of Nano-bentonite Supplementation on Reducing the Toxicity of Aflatoxin B1 in Kampung Unggul Balitbangtan Chickens Diet

Aspergillus flavus and Aspergillus parasiticus are fungi that produce toxic secondary metabolites known as aflatoxins. These toxins can contaminate various food and feed products, including grains and nuts, before or after they are harvested. This contamination is most commonly found in tropical countries. Many studies have demonstrated that clay additions can reduce animal aflatoxin toxicity. The objective of this research was to study how the usage of Pacitan's local bentonite, located in East Java, Indonesia, could potentially decrease the harmful effects of aflatoxin B1 in native chicken species. The Masking Gel Calcification method was used to create bentonite nanoparticles at the Center for Ceramics in Bandung, West Java, Indonesia. The in vivo study was conducted at a native chicken farm in Bantul, Yogyakarta, Indonesia, with 1200 unsexed Kampung Unggul Balitbangtan (KUB) chickens. Kampung Unggul Balitbangtan chickens were divided into 4 treatments and 6 replications, each containing 50 chickens. The diets in the treatments were named as T0 (the control group in which chickens were fed basal diet, without aflatoxin B1), T1 ( T0 + 200 µg/kg aflatoxin B1), T2 (T0 + 200 µg/kg aflatoxin B1 + 1 g/kg Factory Feed with standard factory absorbent), and T3 (T0 + 200 µg/kg aflatoxin B1 + 1 g/kg nano bentonite). Aspergillus flavus isolates from PAU Universitas Gadjah Mada were created using crude aflatoxin (FNC 2262). This study found a significant difference in KUB chicken performance, specifically in feed conversion ratio (FCR). Compared to T0, the findings indicated that T1 had the highest FCR value, followed by T2 and T3. It can be concluded that nanoparticle bentonite has a looser structure because of decreased packing density with the lowest FCR. Based on hematology analysis, it can suppress aflatoxin B1 toxicity in KUB chickens.

Antifungal synergic activity of essential olive oil and alcoholic turmeric extracts against isolates from the dried grapes raisins

Fungi are responsible for a wide variety of harm to humans, including food spoilage and infections. Using chemicals to restrict fungal development or infections has negative repercussions, such as human health dangers from the chemical applications and rising antifungal-drug resistance, so this study aimed to use medicinal plants and their extracts as an alternative method to restrict fungal growth. Ten isolates of the genus Aspergillus were identified from the fruits of dried grapes (raisins) of all kinds (Iraqi black raisins, Iranian yellow raisins, and brown raisins) at the species level using three – differential media: Czapek Yeast Extract Agar( CYA), Malt Extract Agar( MEA), and 25% Glycerol nitrate agar (G25N) incubated in 5, 25 and 37 ºC. Aspergillus niger was the most common isolated species. The number of A. niger isolates reached seven from all types of dried grapes, while A. flavus recorded three isolates from black raisins and brown raisins. Aspergillus Flavus Parasiticus Agar (AFPA) was used to detect the ability of A. flavus isolates to produce aflatoxin at 25-30 ºC for one week. Alcoholic extract of turmeric showed a significant inhibitory effect on the colony diameter of both A. flavus and A. niger isolated from the fruit of Iraqi black raisins with an inhibition rate of 86.6% and 68.8 %, respectively, at 4 mg/ ml concentration. The mixture of turmeric and essential olive oil gave a distinct inhibitory effect, reaching a 100% inhibition rate from the lowest to highest concentration for both A. niger and A. flavus .

WITHDRAWN: Detection and isolation of aflatoxin producing Aspergillus sp. in chewing and smokeless tobacco by microbial and molecular methods

Tobacco contains many harmful chemicals, toxins, and carcinogens that cause serious health hazards. Mycotoxins and aflatoxins are present in all forms of tobacco, including chewing tobacco and smokeless tobacco. Using microbial and molecular techniques, we identified and isolated the aflatoxins-producing fungus Aspergillus species. 50 samples were collected randomly and grown on SDA media by spread plate method. Aspergillus flavus isolates were tested for aflatoxin production using ammonia vapour test. Additionally, their DNA was extracted and utilized for molecular identification. Different fungal genera were observed, including the most commonly found Aspergillus as well as Penicillium, Rhizopus, Candida and Trichophyton. The isolated Aspergillus flavus was characterized by its soft, velvety white surface. The colony diameter ranged from 50 to 70 mm. When exposed to UV light at 365 nm on coconut agar medium, blue-green fluorescence was observed on the reverse side of the colonies. Further, the DNA extracted from all aflatoxin-producing strains was quantified. The study revealed high levels of aflatoxin in 10 different samples, while the remaining samples showed a lower range. The research employed both quantitative and qualitative techniques for the detection of aflatoxin-producing fungi. Notably, aflR and aflS were identified as potential candidates for the detection of aflatoxigenic fungi.

Detection Aflatoxin on the Imported Maize (Zea mays L) Using HPLC in the Areas of Baghdad

This study was conducted in the laboratory of fungi of the Department of biology of the collage of Science in Mustansiriyah University to investigate the contamination of grain (maize ) displayed in the markets of the city of Baghdad mycotoxins type aflatoxin, was isolated the fungi associated with contamination of maize and the number of 10 isolates where the record Aspergillus flavus isolates the most isolates occur 7 Aspergillus niger isolates followed by 2 isolates and one isolated Penicillium sp. ، Aspergillus flavus isolates done Pathogenicity test to identify the isolates of the study. Four isolates were identified (Afla1, Afla2, Afla3, Afla4). The results of the aflatoxin detection in four different samples of positive yellow maize samples showed that all samples tested were contaminated with Aflatoxin, sampled from different regions, Adhamiya, Al-shaab and Palestine Street, had the highest pollution rate of 2149μg/g for Afla 1, while Afla 2 recorded the lowest pollution rate of 114μg/g.

Seaweed extracts as biological control of aflatoxins produced by Aspergillus parasiticus and Aspergillus flavus

BackgroundMycotoxins are secondary metabolites made by a variety of molds and fungi. They contaminate a lot of food products and local crops during pre- and post-harvesting under favorable conditions like high temperature and moisture. Aspergillus species are the most common fungi that contaminate food and produce biochemicals known as mycotoxins. Aflatoxins (AFB1, AFB2, AFG1, and AFG2) are the major mycotoxins produced by A. flavus and A. parasiticus that harm animal and human health. These fungi are controlled by chemical fungicides, but these are harmful to the environment. The aim of this study was to determine whether the aflatoxigenic fungi can be exterminated only by marine algal extracts or not.ResultsThe findings showed that the tested seaweed extracts inhibited fungal growth and aflatoxins production to varying degrees. The maximum antifungal activity was recorded in Halimeda opuntia extract against A. parasiticus-24 and A. flavus-18 and Turbunaria decurrens extract against A. flavus-18 (with an inhibition percentage of 77.78%), followed by Jania rubens extract against A. parasiticus-16 with inhibition percentage 75.88% compared to the control. Aqueous extract of H. opuntia effectively eliminated aflatoxins (B1, B2, G1, and G2) in A. parasiticus-16 and A. parasiticus-24. T. decurrens extract could detoxify 100% of aflatoxins in three isolates of A. parasiticus. J. rubens extract eliminated aflatoxins in A. parasiticus-15 and A. parasiticus-16 compared to their normal production using high-performance liquid chromatography.ConclusionsAccording to this study, the macroalgal species with numerous distinctive antifungal properties constituents significantly inhibited the growth and production of aflatoxin in A. parasiticus and A. flavus isolates. The findings supported the use of macroalgae as a biological control agent against fungi and their toxins.

Impacts of Temperature and Water Activity Interactions on Growth, Aflatoxin B1 Production and Expression of Major Biosynthetic Genes of AFB1 in Aspergillus flavus Isolates.

The contamination of peanuts, with Aspergillus flavus and subsequent aflatoxins (AFs) is considered to be one of the most serious, safety problems in the world. Water activity (aw) and temperature are limiting, factors for fungal growth and aflatoxin production during storage. The objectives of this study were to integrate data on the effects of temperature (34, 37, and 42 °C) and water activity (aw; 0.85, 0.90, and 0.95) on growth rate aflatoxin B1 (AFB1) production and up- or-downregulation of the molecular expression of biosynthetic AFB1 genes divided into three types based on their A. flavus isolate composition and AFB1 capacity in vitro: A. flavus KSU114 (high producer), A. flavus KSU114 (low producer), and A. flavus KSU121 (non-producer). The A. flavus isolates were shown to be resilient in terms of growth on yeast extract sucrose agar media when exposed to temperature and water activity as pivotal environmental factors. The optimal conditions for the fungal growth of three isolates were a temperature of 34 °C and water activity of 0.95 aw; there was very slow fungal growth at the highest temperature of 42 °C, with different aw values causing inhibited fungal growth. The AFB1 production for the three isolates followed the same pattern with one exception: A. flavus KSU114 failed to produce any AFB1 at 42 °C with different aw values. All tested genes of A. flavus were significantly up- or downregulated under three levels of interaction between temperature and aw. The late structural genes of the pathway were significantly upregulated at 34 °C under aw 0.95, although aflR, aflS and most of the early structural genes were upregulated. Compared to 34 °C with an aw value of 0.95, most of the expressed genes were significantly downregulated at 37 and 42 °C with aw values of 0.85 and 0.90. Additionally, two regulatory genes were downregulated under the same conditions. The expression level of laeA was also completely associated with AFB1 production, while the expression level of brlA was linked to A. flavus colonization. This information is required to forecast the actual effects of climate change on A. flavus. The findings can be applied to improve specific food technology processes and create prevention strategies to limit the concentrations of potential carcinogenic substances in peanuts and their derivatives.

Biosynthesis and characterization of chitosan nanoparticles, determination of its antifungal and antiaflatoxigenic against Aspergillus flavus isolates

Aflatoxin is a mycotoxin generated mostly by the fungus Aspergillus flavus, which may be found in food and feed. It is a carcinogenic poison for both humans and animals. The goal of this investigation was to see if toxicogenic A. flavus strains might be found on nuts in the Kurdistan Region. A total of Fifty nut samples. The colony color of A. flavus and texture were used to identify macromorphological qualities, whereas the spore color, size, structure, conidiophore structure, and vesicle shape were used to assess micromorphological properties. Direct imaging of the UV fluorescence of A. flavus colonies on coconut agar media (CAM) was used to detect aflatoxin formation. Natural compounds, such as chitosan, have been suggested as a way to prevent fungal infection because of their extensive and well-known antibacterial action against a variety of microorganisms. The goal of this entry was to morphologically characterize and determine aflatoxigenic A. flavus isolates, characterize nanoparticles using UV–visible, X-ray diffraction (XRD), Energy-dispersive X-ray (EDX), and scanning electron microscope (SEM) analyses, and determine the formulations' in vitro antifungal activity on the treated fungus. Individual concentrations were created by altering the percentages of ingredients such chitosan solution, chitosan nanoparticles, glycerol, and canola oil. The final concentrations of chitosan solution and chitosan nanoparticles were 20% and 2% respectively. Chitosan nanoparticles completely inhibit the growth of A. flavus at 2%.

Surveillance of Mycotoxin contamination and Production of Aflatoxin by A. flavus in Contaminated Maize Seeds in Bihar

Aflatoxin- producing fungi like Aspergillus flavus contaminate maize crops in the agricultural field at harvest, post- harvest, and during storage making them one of the most widespread and dangerous mycotoxins. It has been directly correlated to adverse health effects, such as liver cancer in many animal species as well as plant systems.
 Maize samples were collected from seven districts of Bihar viz, Begusari, East Champaran, Khagaria, Bhagalpur, Saharsa, Madhepura, and Samastipur. The collected sample was examined for associated mycoflora and aflatoxin-producing prospective of Aspergillus flavus. It was determined that A. flavus was of presiding occurrence accompanied by Penicillium spp., Fusarium, A. nigar, Rhizopus, Trichoderma, Mucor and A. ochraceus. 119 strains of the total A. flavus isolates were toxigenic, producing aflatoxin B1, B2, and G1. The highest Aflatoxin is all probability due to complementary environmental conditions, undeveloped agricultural practices, poor storage circumstances of grains, and because of yearly flood problems in this region.

Isolation of Aspergillus flavus strains from Bambara groundnut (Vigna subterranea (L.) Verdcourt) seeds and screening for the production of aflatoxin B1 and B2

In Burkina Faso, Bambara groundnut is the second most important food legume after cowpea, especially in rural areas. However, this crop, due to certain conditions of production, storage or preservation is susceptible to be contaminated by potential mycotoxin producing fungi. The aim of this study was to evaluate the aflatoxinogenic capacity of Aspergillus flavus isolates isolated from Bambara groundnut seeds produced in Burkina Faso. Thus, 198 isolates of fungi belonging to section Flavi were isolated from 99 samples of Bambara groundnut seeds collected in the three agro-ecological zones of Burkina Faso. From the 198 isolates, 28 were identified as Aspergillus flavus. Then, we investigated their potential for aflatoxin B1 (AFB1) and B2 (AFB2) production by growing them on rice at 25°C for 7 days. AFB1 and AFB2 were extracted and quantified by liquid chromatography–mass spectrometry (LC-MS/MS). All of the strains (28) produced AFB1 at concentrations ranging from 46.987 μg kg–1 to 1080.320 μg kg–1. However, AFB2 was produced by 26 strains with concentrations ranging from 47.200 μg kg–1 to 1760.240 μg kg–1. Globally, most of the tested strains produced higher levels of AFB1 than AFB2. The results obtained point out the risk associated with post-harvest fungi and the need for the development of storage technics to control them, for food security.