Aspergillus Parasiticus Research Articles

Antifungal activity of poly(lactic acid) nanofibers containing the essential oil from Corymbia citriodora Hook or the monoterpenes β-citronellol and citronellal against mycotoxigenic fungi.

Food contamination by mycotoxigenic fungi is one of the principal factors that cause food loss and economic losses in the food industry. The objective of this work was to incorporate the essential oil from Corymbia citriodora Hook and its constituents citronellal and β-citronellol into poly(lactic acid) nanofibers; to characterize the nanofibers by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC); to evaluate the antifungal activity by the fumigation method; to evaluate the antimycotoxigenic activity against Aspergillus carbonarius, Aspergillus ochraceus, Aspergillus westerdijkiae, Aspergillus flavus and Aspergillus parasiticus; and to evaluate the morphology of these microorganisms. All the nanofibers had a regular, smooth and continuous morphology. FTIR analyses confirmed that the active ingredients were incorporated into the polymer matrix. All samples exhibited antifungal and ochratoxigenic inhibitory activities of up to 100% and 99%, respectively, with the best results observed for (PLA + 30 wt% β-citronellol) nanofibers and (PLA + 30 wt% citronellal) nanofibers. However, 100% inhibition of the production of aflatoxin B1 and B2 was not observed. The images obtained by SEM indicated that the nanofibers caused damage to the hyphae, caused a decrease in the production of spores, and caused deformation, rupture and non-formation of the conid head, might be an alternative for the control of mycotoxigenic fungi.

Assessment of Fungal Contamination and Their Toxigenic Potential of Farmed Fish in Western Algeria

Fish and fish products have been documented as a major source of pathogens, with fungi playing a key role. In this paper, a survey was conducted to determine the presence of fungi in fish reared in various aquaculture farms in western Algeria, namely Nile Tilapia (Oreochromis niloticus), gilthead sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax). The search for micromycetes was carried out on different parts of the body: skin and flesh, gills, and intestines. A total of 1937 fungal strains were revealed and divided into 10 genera of filamentous fungi, one genus of yeast, and other yeasts that have not yet been determined. Penicillium was the most common genus, representing 41.56% of the fungal population, fol-lowed by Rhodotorula (17.60%), and Aspergillus (15.95%). The greatest number of isolates was identified in the gills of gilthead sea bream, while the lowest number was isolated from sea bass intestines. Secondly, we sought to highlight the toxigenic potential of the fungal strains isolated, using the brine shrimp lethality test. Five of the fungal strains tested, belonging to the two genera Penicillium and Aspergillus, showed toxic potential for Artemia salina. The highest toxicities were observed mainly by strains of Aspergillus parasiticus (APAR001), Aspergillus terreus (ATER002), and Aspergillus niger (ANIG001) respectively. Penicillium chrysogenum (PCHR002) showed the lowest activity. These results confirm the infection of farmed fish by toxigenic fungal communities, which can present a real health hazard to consumers. Regular monitoring and compliance with fish health management practices are recommended.

Antifungal Effects of Rosmarinic Acid, α-Tocopherol and α-Tocopherol Acetate on Aspergillus parasiticus (NRRL 2999) and Candida albicans (MTCC 183) and Assessment of Chitin and Ergosterol Biomarkers

Antifungal Effects of Rosmarinic Acid, α-Tocopherol and α-Tocopherol Acetate on Aspergillus parasiticus (NRRL 2999) and Candida albicans (MTCC 183) and Assessment of Chitin and Ergosterol Biomarkers

Characteristics of inhibition of Aspergillus flavus growth and degradation of aflatoxin B1 by cell-free fermentation supernatant of Bacillus velezensis 906

Aflatoxin, a harmful secondary metabolite produced by Aspergillus flavus and Aspergillus parasiticus, poses a significant risk to human health and food safety. Therefore, the development of safe and environmentally friendly techniques for controlling A. flavus and its aflatoxin production is imperative. In this study, Bacillus velezensis 906 cell-free fermentation supernatant (CFS) inhibited the germination of A. flavus spores and mycelium growth. Scanning electron microscopy and fluorescence microscopy revealed that CFS altered cell morphology and damaged the cell membrane of A. flavus leading to cell death. Fourier transform infrared spectroscopy indicated changes in the functional groups of A. flavus filaments treated with CFS. The trend in ergosterol content demonstrated that CFS effectively inhibited the normal growth of A. flavus cell membranes. The CFS exhibited remarkable efficacy in degrading aflatoxin B1 (AFB1), achieving a degradation rate of up to 60% after 48 h of interaction. The addition of 0.2 mg/mL Cu2+ or Fe3+ metal ions to CFS significantly increased the degradation rate of AFB1 up to 90%. Furthermore, the analysis indicated that the active components responsible for AFB1 degradation might be heat-resistance and exhibit resistance to protease K. These findings underscore the potential of CFS as a green, safe, and economically viable strategy for controlling aflatoxin production by A. flavus, offering promising prospects for mitigating mold contamination in food and feed applications.

Exploring the aroma profile and biomedical applications of Scutellaria nuristanica Rech. F.: A new insight as a natural remedy

BackgroundThe Scutellaria genus has promising therapeutic capabilities as an aromatherapy. Based on that and local practices of S. nuristanica Rech. F. The essential oil was studied for the first time for its diverse biomedical applications. PurposeThis study aimed to evaluate and validate their therapeutic capabilities by screening the essential oil ingredients and examining their antimicrobial, antioxidant, carbonic anhydrase, and antidiabetic using further In silico assessment and In vivo anti-inflammatory and analgesic capabilities to devise novel sources as natural remedies alternative to the synthetic drugs. MethodsEssential oil was obtained through hydrodistillation, and the constituents were profiled using GC–MS. The antimicrobial assessment was conducted using an agar well diffusion assay. Free radical scavenging capabilities were determined by employing DPPH and ABTS assay. The carbonic anhydrase-II was examined using colorimetric assay, while the antidiabetic significance was performed using α-Glucosidase assay. The anti-inflammatory significance was examined through carrageenan-induced paw edema, and the analgesic features of the essential oil were determined using an acetic acid-induced writhing assay. ResultsFifty constituents were detected in S. nuristanica essential oil (SNEO), contributing 95.93 % of the total EO, with the predominant constituents being 24-norursa-3,12-diene (10.12 %), 3-oxomanoyl oxide (9.94 %), methyl 7-abieten-18-oate (8.85 %). SNEO presented significance resistance against the Gram-positive bacterial strains (GPBSs), Bacillus atrophaeus and Bacillus subtilis, as compared to the Salmonella typhi and Klebsiella pneumoniae, Gram-negative bacterial strains (GNBSs) as well as two fungal strains Aspergillus parasiticus and Aspergillus niger associated with their respective standards. Considerable free radical scavenging capacity was observed in DPPH compared to the ABTS assay when correlated with ascorbic acid. In addition, when equated with their standards, SNEO offered considerable in vitro carbonic anhydrase II and antidiabetic capabilities. Additionally, the antidiabetic behavior of the 9 dominant compounds of SNEO was tested via In silico techniques, such as molecular docking, which assisted in the assessment of the significance of binding contacts of protein with each chemical compound and pharmacokinetic evaluations to examine the drug-like characteristics. Molecular dynamic simulations at 100 ns and binding free energy evaluations such as PBSA and GBSA models explain the molecular mechanics and stability of molecular complexes. It was also observed that SNEO depicted substantial anti-inflammatory and analgesic capabilities. ConclusionHence, it was concluded that the SNEO comprises bioactive ingredients with biomedical significance, such as anti-microbial, antioxidant, CA-II, antidiabetic, anti-inflammatory, and analgesic agents. The computational validation also depicted that SNEO could be a potent source for the discovery of anti-diabetic drugs.

Isolation of aflatoxin biosynthetic inhibitor from Chondrostereum purpureum mushroom culture filtrate

Aflatoxins (AFs) are highly toxic mycotoxins produced by the fungi, Aspergillus flavus and Aspergillus parasiticus. AFs pose severe health risks owing to their acute toxicity and carcinogenic properties. The control of AF contamination remains significantly challenging despite the extensive efforts toward controlling it. Here, we investigated the potential of mushroom extracts as a source of AF biosynthetic inhibitors. The A.parasiticus mutant strain, NFRI-95, that accumulates an AF biosynthesis intermediate, norsolorinic acid, was used in the bioassay to detect the inhibitory activity against AF biosynthesis. The screening of 195 mushroom extracts revealed that the culture filtrate extract of Chondrostereum purpureum exhibited strong inhibitory activity against AF biosynthesis. Next, large-scale culturing of C.purpureum was performed to isolate the compounds accounting for the inhibitory activity. The culture filtrate was extracted with ethyl acetate, after which the active compound was isolated by silica gel column chromatography and preparative high performance liquid chromatography (HPLC). The active compound was identified as cyclo(Val-Pro) by spectroscopic analyses. Further, four stereoisomers of cyclo(Val-Pro) were synthesized by the condensation of the N-Boc derivatives of d- and l-valine with the methyl esters of d- and l-proline. The naturally isolated compound was identified as cyclo(l-Val-l-Pro) by comparing its retention time with those of synthetic compounds by chiral HPLC analysis and CD spectra. The IC50 value of cyclo(L-Val-L-Pro) was 2.4mM, whereas the LD, DL, and DD isomers exhibited weaker activities, with IC50 values of >5mM.

Three Ecological Models to Evaluate the Effectiveness of Trichoderma spp. for Suppressing Aflatoxigenic Aspergillus flavus and Aspergillus parasiticus.

Chemical pesticides help reduce crop loss during production and storage. However, the carbon footprints and ecological costs associated with this strategy are unsustainable. Here, we used three in vitro models to characterize how different Trichoderma species interact with two aflatoxin producers, Aspergillus flavus and Aspergillus parasiticus, to help develop a climate-resilient biological control strategy against aflatoxigenic Aspergillus species. The growth rate of Trichoderma species is a critical factor in suppressing aflatoxigenic strains via physical interactions. The dual plate assay suggests that Trichoderma mainly suppresses A. flavus via antibiosis, whereas the suppression of A. parasiticus occurs through mycoparasitism. Volatile organic compounds (VOCs) produced by Trichoderma inhibited the growth of A. parasiticus (34.6 ± 3.3%) and A. flavus (20.9 ± 1.6%). The VOCs released by T. asperellum BTU and T. harzianum OSK-34 were most effective in suppressing A. flavus growth. Metabolites secreted by T. asperellum OSK-38, T. asperellum BTU, T. virens OSK-13, and T. virens OSK-36 reduced the growth of both aflatoxigenic species. Overall, T. asperellum BTU was the most effective at suppressing the growth and aflatoxin B1 production of both species across all models. This work will guide efforts to screen for effective biological control agents to mitigate aflatoxin accumulation.

Isolation, identification, biological characteristics, and pathogenicity of an entomogenous fungus against the Egyptian mealybug, Icerya aegyptiaca (J.) (Hemiptera: Monophlebidae)

BackgroundIn this study, an entomogenous, fungus was isolated from the Egyptian mealybug, Icerya aegyptiaca (J.) (Hemiptera: Monophlebidae) on the parasol leaf tree, Macaranga tanarius, in China where evaluated as a biocontrol fungus to reduce the population of the target insect. The strain was identified as Aspergillus parasiticus by morphological and phylogenetic analysisand named ZHKUAP1. The biological characteristics, pathogenicity, and field control effect of the strain were determined.ResultsThe most suitable medium for the mycelial growth of strain ZHKUAP1 was PPDA medium, with an optimum temperature of 30 °C and pH 7, in addition to glucose and peptone as carbon and nitrogen sources. The optimum sporulation conditions were the PPDA medium at 30 °C and pH 6, using the soluble starch and beef extract as carbon and nitrogen sources. The mycelial growth and spore production of strain ZHKUAP1 were stopped at 70 °C and above, indicating that it was not resistant to high temperatures. High concentrations of spore suspension, against young insect age, resulted high corrected mortality, as well as decreased the median lethal time. When the spore concentration was 1 × 108 cfu/ml, the corrected mortality of the second nymph was 88.33%, and the LT50 was 0.66 day. After 10 days of inoculation, the LC50 of the second instar nymph was the smallest, reaching 4.07 × 104 cfu/ml. On the 10th day of the field experiment, the corrected mortality was 76.45%, indicating that the A. parasiticus strain ZHKUAP1 had strong pathogenicity on I. aegyptiaca population.ConclusionsThe indoor toxicity of the strain to I. aegyptiaca was determined, and the field control effect of the pathogen was explored on this basis. The results have important application prospects in the biological control of I. aegyptiaca.

Influence of Aspergillus parasiticus on aflatoxins production and quality change in Chrysanthemum morifolium at various storage conditions

SummaryIn this study, a full factorial design with three temperature levels (20, 30 and 40 °C), three moisture content (MC) levels (8%, 15% and 22%), and four storage times (7, 14, 21 and 28 days) was used to investigate the changes of aflatoxins (AFs), active constituents, and antioxidant activities in Hangbaiju (HBJ, Chrysanthemum morifolium) after simulated inoculation with Aspergillus parasiticus. The results showed that AFs could be produced in the range of 20~30 °C and 8~22% MC after mould infection, but both mould growth and AFs production were inhibited under the tested MC condition at 40 °C. The analysis of variance (anova) indicated that the temperature, time, interaction between the temperature and time, and interaction between MC and time had significant effects on the total aflatoxins (AFTOT) accumulation. Under 20 and 30 °C, AFTOT in inoculated HBJ usually increased with the increase of MC and storage time, while its active constituents and antioxidant activities decreased with the increase of AFTOT under corresponding storage conditions. Pearson correlation analysis suggested that relatively stronger negative correlations were observed between luteolin‐7‐O‐glucoside (LUT7G), total phenolic content (TPC), total flavonoid content (TFC), and AFTOT. Grey correlation analysis (GCA) showed that antioxidant activity was highly linked to the content of active constituents, and the characteristic flavonoid LUT7G exhibited the highest grey correlation degrees (GCDs) in the three antioxidant activities. The AFTOT reached the highest level (31.15 μg kg−1) after 28 days of storage at 30 °C and 22% MC; meanwhile, LUT7G, TPC and TFC decreased by 93.66%, 20.77% and 55.50%, respectively, and all the three antioxidant activities indicated more than 25% reduction. This is the first study about the changes and relationships of AFTOT, active constituents and bioactivities in the medicinal food influenced by A. parasiticus under different storage conditions. These results provide important references to prevent AFs production and quality control for HBJ and other medicinal foods influenced by A. parasiticus in storage strategy.

Aflatoxin exploration in basmati brown rice collected from various locations of Lahore, Pakistan

Aflatoxins are produced by various fungal species, the two primaries being Aspergillus flavus and Aspergillus parasiticus. Aflatoxins contaminate various food products, resulting in them being toxic and unsafe for consumption, hence, being classified as potent carcinogens. In this paper, samples of brown basmati rice were analyzed for contamination with aflatoxins using the ELISA method. 50 brown rice samples were collected from various shops in Lahore, Pakistan, in the year 2019-2020. During summer, 25 of the samples were collected from April-September whereas the rest 25 were collected in winter from October-March. The rice samples were in a poor condition because of high levels of aflatoxin contaminations. The percentage of aflatoxins contamination for summer and winter was 88% and 80% respectively. Further, 60% of summer collected samples and 44% of winter collected samples exceeded the permissible level allowed by European Union (10μg/kg for total aflatoxins). The samples with the highest aflatoxin for summer contained 49.60±0.45μg/kg whereas for winter the concentration was 25.07±0.04 μg/kg. With regard to their toxic nature and harm to human health, these calculated levels were frightening. These show a dire need for the implementation of practices to monitor the quality of these rice by all the rice producers and storage holders in Pakistan.

Impact of gliding arc cold plasma on deactivating of aflatoxin and post-treatment fungal growth on wheat grains

Wheat, a strategic global agricultural product, is prone to contamination by hazardous fungi and toxins, with aflatoxin being particularly prevalent and perilous. This study aimed to evaluate the efficacy of cold plasma in deactivating Aspergillus flavus (A.f.) and Aspergillus parasiticus (A.p.), as well as aflatoxins in wheat grains, offering an alternative to conventional chemical and thermal treatments. Wheat grains inoculated with fungi were subjected to humid air cold plasma at four power levels (5.39, 6.88, 8.98, and 10.88 W) and three plasma exposure periods (2, 6, and 12 min). Post-plasma treatment, Aflatoxin concentrations were analyzed using HPLC, while modified Gompertz and Baranyi and Roberts’ mathematical models were employed to study the growth kinetics of A.f. and A.p. species. Findings revealed that samples treated with 10.88 W power for 12 min exhibited a substantial reduction of 64%, 41%, 59%, 40%, and 61% in B1, B2, G1, G2 aflatoxins, and total aflatoxin, respectively. Additionally, plasma led to a 78.74% and 68.57% reduction in the growth of A.f. and A.p. fungi, respectively. Notably, plasma induced a fungal inhibitory effect by prolonging the lag time and decreasing the growth rate. These results underscore the significant potential of cold plasma as a capable technique for fungal inactivation and the emerging disinfection of contaminated wheat grains.

Characterizing the antioxidant and antifungal properties of nano-encapsulated pistachio hull extract in fenugreek seed gum to maintain the quality and safety of fresh pistachio.

The quality of pistachio, one of the export products of Iran, will be decreased during storage as a result of mold spoilage, toxins production, and oil oxidation. This study aimed to investigate the capability of pistachio hull extract (PHE) loaded in fenugreek seed gum (FSG):whey protein isolate (WPI) nanoemulsion to control oil oxidation, and fungi growth in fresh pistachio nut during storage at 4°C. The total anthocyanin and total phenolic content of the PHE were 125.44 μg/g and 675.18 mg/g, respectively. The DPPH radical scavenging activity of PHE at 100 ppm was higher than that of tert-butylhydroquinon (TBHQ). In comparison with other concentrations, 50 ppm showed the strongest antifungal activity against Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius. All nanoemulsions have a mean size lower than 265 nm. The polydispersity index (PDI) of different nanoemulsions was lower than 0.3, and a negative zeta potential was observed. The encapsulation efficiency was higher than 67.0% and all nanoemulsions had spherical morphology. The pistachio nuts were coated with different coating solutions containing 0 and 100 ppm of PHE and stored at 4°C for 8 weeks. The results showed that the pistachio sample coated with a composite coating of WPI and FSG containing 100 ppm of PHE has a higher moisture content and lower changes in L*, a*, and b* indexes, oil oxidation, fungi development, and total mold and yeast count. This treatment exhibited higher overall acceptance than other samples at the end of storage time. The results of this study suggest the use of biodegradable coatings enriched with natural extracts that have high antioxidant and antifungal activities.

Isolation, Characterization, and Biopreservation of Lactobacillus brevis DN-1 to Inhibit Mold and Remove Aflatoxin B1 in Peanut and Sunflower Cakes

Aflatoxin B1 (AFB1) is the most toxic mycotoxin and is widespread in moldy feed. The use of biological removal methods to reduce AFB1 has become a research hotspot. This study aimed to isolate lactic acid bacteria (LAB) capable of removing AFB1 from moldy feeds and assessed the removal capacity under various environmental conditions. A strain named Lactobacillus brevis DN-1 was isolated from feed samples and showed 71.38% AFB1 percent removal. Furthermore, DN-1 showed good antifungal activity against Aspergillus flavus BNCC336156 and Aspergillus parasiticus BNCC335939. The optimum growth temperature and pH of DN-1 were 37 °C and 6.0, respectively, and DN-1 grew well in the concentration range of 0–20 µg/L AFB1. Under a temperature of 20–40 °C, pH of 3.0–9.0, and anaerobic conditions, the percent removal of AFB1 was more than 60%. An analysis of the different components of DN-1 showed that cell wall adsorption was the main removal method and suggested the pathway for AFB1 removal by LAB. In addition, strain DN-1 was used as a biological preservative in artificially contaminated peanut and sunflower cakes, which significantly inhibited the growth of mold and production of AFB1. In brief, this study highlights the potential use of DN-1 as a preventive agent against aflatoxicosis via strong removal capability in the application of fermented feed or food.

Fungal Isolation and Characterization from some Ornamental Plants in Baze University Abuja, Nigeria

A research was carried out to isolate and characterize the fungal community present on some ornamental plants grown in Baze University Abuja Nigeria. Leaf samples showing diseased symptoms were collected from four different ornamental plants in the area (Indian shot, Canna indica; Plantain lily, Hosta undulata; Elephant ear, Caladium sp; and Song of India, Pleomelere flexa. The diseased portions were cut to form an aliquot. Serial dilutions were carried out and the samples were inoculated on Potato Dextrose Agar and incubated at 27 oC for 5 days. Fungal colonies formed were counted and sub-cultured. Data obtained for occurrence was analyzed in frequency and percentages while for enumeration using Analysis of Variance (ANOVA) with Duncan’s New Multiple Range Test was used to separate significant means at 5% level. The result obtained revealed the presence of ten fungal species represented by eight genera associated with the plants: Aspergillus niger, Aspergillus parasiticus, Mucor racemosus, M. mucedo, Saccharomyces cerevisiae, Fusarium oxysporum, Rhizopus stolonifer, Alternaria alternata, Pythium aphanidermatum and Penicillium chrysogenum. Aspergillus niger is the most predominant species. Elephant ear has the highest fungal loads. Four of the fungal species: A. alternata, Aspergillus parasiticus, Pythium aphanidermatum and Fusarium oxysporum are potential pathogens while the remaining six species are saprophytes. This implies that the plants are at risk of losing their aesthetic values as such proper attention need to be given to these plants.

Meat Starter Culture Reduces Aspergillus parasiticus Production of Aflatoxins on Meat-Based and Salami Model Media.

There is great concern about the risk posed by the consumption of food contaminated with aflatoxins (AF), produced mostly by Aspergillus strains, that can also be found in dry-fermented meat products (DFMPs). The aim of this study was to investigate the inhibitory effect of meat starter culture (SC), frequently used for fermentation in the meat industry, on A. parasiticus growth and the production of aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), and sterigmatocystin (STE) on different meat-based (CMA) and salami model (SM-G) media. Incubation was carried out under optimal conditions for fungal growth and under typical conditions for ripening of DFMPs for 21 days. Reversed-phase UPLC-MS/MS analysis was performed to determine mycotoxin production. SC reduced A. parasiticus growth more on CMA than on SM-G media. AFB1 formation was inhibited on both types of SC-containing media, although SC generally had a stronger inhibitory effect on AFB1 production on CMA than on SM-G. AFB1 and AFB2 were produced on CMA, while AFB1 dominated in SM-G, AFG1, and AFG2 were not detected in any media. The results show that SC inhibited AFB1 formation of A. parasiticus on SM-G media after 21 days of incubation under typical conditions for the production of DFMPs. These results indicate the necessity to investigate AF on natural matrices in an environment that is as similar as possible to real conditions in the production of DFMPs.

The in Vitro Effect of Berberine Sulfate and Berberine Chloride on the Growth and Aflatoxin Production by Aspergillus flavus and Aspergillus parasiticus

Background: Aflatoxins are harmful mycotoxins that can contaminate animal and human food products. To prevent toxigenic fungi growth and aflatoxin production, researchers have long investigated plant compounds as potential inhibitory agents. Objectives: This study aimed to evaluate the in vitro effect of berberine sulfate and berberine chloride on the growth and aflatoxin production of Aspergillus flavus and Aspergillus parasiticus. Methods: The antifungal activity of berberine salts was determined according to the Clinical and Laboratory Standards Institute (CLSI) document M38-A3. The aflatoxin levels were measured using high-performance liquid chromatography (HPLC) method. Results: The berberine sulfate and berberine chloride showed inhibitory effects against both Aspergillus species, with minimum inhibitory concentration (MIC) ranging from 125 to 500 µg/mL. Berberine sulfate at 2000 μg/mL and berberine chloride at 1000 μg/mL completely inhibited the mycelial growth of A. flavus, while berberine chloride at 1000 μg/mL also completely inhibited the mycelial growth of A. parasiticus. Berberine sulfate at 2000 µg/mL reduced the mycelial growth of A. parasiticus by 96.7%. Conclusion: Berberine salts significantly decreased the total aflatoxin production of Aspergillus species at MIC/2 and MIC/4 concentrations (P˂0.05). The results suggest that berberine salts could be used as potential antifungal and anti-aflatoxigenic agents against toxigenic Aspergillus isolates.

Mass Spectrometry-Based Method to Measure Aflatoxin B1 DNA Adducts in Formalin-Fixed Paraffin-Embedded Tissues.

Aflatoxin B1 (AFB1) is a potent human liver carcinogen produced by certain molds, particularly Aspergillus flavus and Aspergillus parasiticus, which contaminate peanuts, corn, rice, cottonseed, and ground and tree nuts, principally in warm and humid climates. AFB1 undergoes bioactivation in the liver to produce AFB1-exo-8,9-epoxide, which forms the covalently bound cationic AFB1-N7-guanine (AFB1-N7-Gua) DNA adduct. This adduct is unstable and undergoes base-catalyzed opening of the guanine imidazolium ring to form two ring-opened diastereomeric 8,9-dihydro-8-(2,6-diamino-4-oxo-3,4-dihydropyrimid-5-yl-formamido)-9-hydroxy-aflatoxin B1 (AFB1-FapyGua) adducts. The AFB1 formamidopyrimidine (Fapy) adducts induce G → T transversion mutations and are likely responsible for the carcinogenic effects of AFB1. Quantitative liquid chromatography-mass spectrometry (LC-MS) methods have shown that AFB1-N7-Gua is eliminated in rodent and human urine, whereas ring-opened AFB1-FapyGua adducts persist in rodent liver. However, fresh frozen biopsy tissues are seldom available for biomonitoring AFB1 DNA adducts in humans, impeding research advances in this potent liver carcinogen. In contrast, formalin-fixed paraffin-embedded (FFPE) specimens used for histopathological analysis are often accessible for molecular studies. However, ensuring nucleic acid quality presents a challenge due to incomplete reversal of formalin-mediated DNA cross-links, which can preclude accurate quantitative measurements of DNA adducts. In this study, employing ion trap or high-resolution accurate Orbitrap mass spectrometry, we demonstrate that ring-opened AFB1-FapyGua adducts formed in AFB1-exposed newborn mice are stable to the formalin fixation and DNA de-cross-linking retrieval processes. The AFB1-FapyGua adducts can be detected at levels comparable to those in a match of fresh frozen liver. Orbitrap MS2 measurements can detect AFB1-FapyGua at a quantification limit of 4.0 adducts per 108 bases when only 0.8 μg of DNA is assayed on the column. Thus, our breakthrough DNA retrieval technology can be adapted to screen for AFB1 DNA adducts in FFPE human liver specimens from cohorts at risk of this potent liver carcinogen.

Detection of aflatoxin in raw and pasteurized milk by high-performance liquid chromatography (HPLC) in central Ethiopia

Aflatoxins are a group of structurally related mycotoxins produced by the Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius species as secondary metabolites. Well-known forms of Aflatoxin are AFB1, AFB2, AFG1, AFG2, AFM1, and AFM2. aflatoxin B1 is the most prevalent one. It can be metabolized in the liver and excreted as aflatoxin M1 in milk. Both forms have mutagenic and carcinogenic effects. In Ethiopia, there is limited information on the occurrence and contamination level of aflatoxin in raw and pasteurized milk. The present study was conducted in the Addis Ababa milk shed area to detect and quantify the level of Aflatoxin M1 in raw and pasteurized milk. A cross-sectional study was conducted from October 2020 to May 2021 on a total of 114 cow milk samples consisting of 60 raw milk and 54 pasteurized milk samples with the aim of detecting and quantifying the amount of aflatoxin M1 in raw and pasteurized milk in central Ethiopia by high-performance liquid chromatography (HPLC) using C18 column with fluorescence detector. AFM1 was detected in 79 (69.3%) of the 114 tested milk samples. The maximum and mean concentrations were 0.893 µg/L and 0.0465 µg/L, respectively. 25.4% of them contain AFM1 above the maximum limit of EU (0.05 µg/L), and 1.8% contained above the maximum limit of CES278 and FDA (0.5 µg/L). 26.7% of the samples from Sebata and 6.7% from Sululta contain above the maximum limit of EU (0.05 µg/L). Higher contamination of AFM1 was detected in pasteurized milk (96.3%) than in raw milk (16.7%). 35.2% of pasteurized and 16% of raw milk contained AFM1 above the maximum limit of EU0.05 µg /L. The study results showed a significant difference in AFM1 occurrence with feed type, storage time, and milk type. The current AFM1 concentration level in raw and pasteurized milk was not safe for human consumption in the study areas. Due to its heat resistance, AFM1 is found in pasteurized milk and has great health effects. Creating awareness of feed management for feed producers and farmers and developing risk mitigation methods are crucial in order to reduce public health threats.

Corn processing by pulsed electric fields with respect to microbial inactivation and improvement of seed vigour

Pulsed electric field (PEF) treatment of corn grains to improve seed vigour and inactivation of endogenous microflora by energies ranging from 1.20 to 28.8 J were applied to determine effectiveness of applied energies on germination rate (GR), normal seedling rate (NSR), electrical conductivity (EC), ability to germinate under salt (100- and 200 mM salt) and cold (at 10 °C for 7 days and at 25 °C for 5 days) stresses. Moreover, the effect of PEF treatments was further investigated for the inactivation of total aerobic mesophilic bacteria (TAMB), total mold and yeast (TMY), and inactivation rate (%) of Aspergillus parasiticus. Increased energy provided 11.10 % increase in GR, 21.22 % increase in NSR, 95.50 % increase in germination at 10 °C for 7 days. Germination under stress conditions revealed 32.53 %, 68.35 %, and 76 % increase in germination at 25 °C for 5 days, under 100 mM- and 200 mM NaCI salt stresses. Inactivation on the mean initial TAMB and TMY were approximately 9.25 and 7.93 log, respectively, with 63.33 ± 0.22 % reduction in A. parasiticus culture. PEF treated corn seedlings had stronger and taller body formation with stronger roots. The most optimal processing parameters were detected as 300 Hz, 28.80 J, and 19.78 sec. PEF treatment carries a high potential to improve corn vigour with inactivation of surface microflora.

Afflatoxine Effect on Livestock Health: A Review

Aflatoxins have been the cause of numerous deaths in livestock and it also the cause for economic losses. Aflatoxins belong to a group of mycotoxins that are produced by fungi species (molds) as they grow on their substrates. The major ones are aflatoxins B1, B2, G1 and G2, thus named depending on their fluorescence under blue and green light. Aspergillus parasiticus can synthesize AFB1, AFB2, AFG1, and AFG2. AFB1=AFM1>AFG1>AFB2=AFM2>AFG2 from strongest to weakest in terms of toxicity. Pigs so affected became lethargic, did not eat, and eventually became hypothermic, icteric, and had blood in their feces. Acute aflatoxicosis is characterized by an acute hepatotoxic disease that manifests itself with depression, anorexia, jaundice, hemorrhages, edema of the lower extremities, abdominal pain and vomiting. Chronic exposure leads liver cancer. The major target organ for aflatoxins in animals is the liver. Aflatoxins are probably not major causes of livestock disease and low productivity, but are contributing factors which are likely to become more important as livestock production intensifies. The animal feeds most likely to be contaminated are maize, cottonseed, and groundnuts. These feeds are at high risk for aflatoxin contamination. Aflatoxins cannot be detected by sight or smell in contaminated food or feed. Aflatoxins are not eliminated by boiling, cooking, or by processing into compound feeds. Animal source foods, especially milk, may also contain aflatoxins if animals eat contaminated feeds. This is often the case with milk; carry-over rates are relatively high, consumption is high, and milk is often given to infants and young children who are most at-risk for negative health outcomes related to aflatoxin exposure. Affected animals may exhibit reduced feed consumption, weight loss, and reduction in production. The more significant effects in cattle may occur when animals consume lower levels of aflatoxins and chronic effects appear such as reduced reproductivity, immunosuppression, and reduced feed efficiency. An increase in dietary protein protects against adverse effects of the toxin. Feeding of extra vitamins, A and K could also decrease the detrimental effects of aflatoxins. The prevention ways are removing the sources; promotes better agricultural and storage techniques; have good resources for testing and early diagnosis; strict food quality standards; General awareness and personal protection; Better livestock feeding & management.