Mycotoxigenic potential of fungi isolated from freshly harvested Argentinean blueberries

Survey and toxigenic abilities of Aspergillus, Fusarium, and Alternaria fungi from wheat and paddy grains in Shanghai, China

A systematic study was carried out on 638 wheat and paddy grains (including fresh and stored samples) collected in 2021 from Shanghai, China, to identify the major mycobiota and their toxigenic abilities. A total of 349 fungi, namely, 252 Fusarium, 53 Aspergillus, and 44 Alternaria, were characterized by morphological and molecular identification. Fusarium and Aspergillus were more frequently isolated in paddy with Fusarium sambucinum species complex and Aspergillus section flavi as the predominant species, respectively. The genus Alternaria was the most frequently isolated fungal species in wheat. The toxin-producing potentials of the identified fungi were further evaluated in vitro. Deoxynevalenol (DON) was produced by 34.5% of Fusarium isolates and zearalenone (ZEN) was produced by 47.6% of them, and one isolate also processed the abilities for fumonisin B1 (FB1), B2 (FB2), and B3 (FB3) productions. Aflatoxin B1 (AFB1), B2 (AFB2), and G1 (AFG1) were only generated by Aspergillus section flavi, with the production rate of 65.5%, 27.6%, and 13.8%, respectively. Alternariol (AOH) was the most prevalent Alternaria toxin, which could be produced by 95.5% of the isolates, followed by alternariol monomethyl ether (AME) (72.7%), altenuene (ALT) (52.3%), tenuazonic acid (TeA) (45.5%), tentoxin (TEN) (29.5%), and altenusin (ALS) (4.5%). A combinational analysis of mycobiota and toxigenic ability allowed us to provide comprehensive information about the production mechanisms of mycotoxins in wheat and paddy in a specific geographic area, and will be helpful for developing efficient prevention and control programs.

Seasonal and Geographical Impact on the Mycotoxigenicity of Aspergillus and Fusarium Species Isolated from Smallholder Dairy Cattle Feeds and Feedstuffs in Free State and Limpopo Provinces of South Africa

This study evaluated the impact of seasonal and geographical variations on the toxigenicity of Aspergillus and Fusarium strains previously isolated from smallholder dairy cattle feeds and feedstuffs sampled during summer and winter in the Free State and Limpopo provinces of South Africa (SA). In total, 112 potential toxigenic fungal species were obtained and determined for their capability to produce mycotoxins on solid Czapek Yeast Extract Agar (CYA); followed by liquid chromatography-mass spectrometry (LC-MS/MS) analysis. Our result revealed that 41.96% of the fungal species produced their respective mycotoxins, including aflatoxin B₁ (AFB₁), aflatoxin B₂ (AFB₂), and zearalenone (ZEN), with higher levels of AFB₁ (0.22 to 1045.80 µg/kg) and AFB₂ (0.11 to 3.44 µg/kg) produced by fungal species isolated from summer samples than those in winter [(0.69 to 14.44 µg/kg) and (0.21 to 2.26 µg/kg), respectively]. The same pattern was also observed for AFB₁ and AFB₂ in Limpopo (0.43 to 1045.80 µg/kg and 0.13 to 3.44 µg/kg) and Free State (0.22 to 576.14 µg/kg and 0.11 to 2.82 µg/kg), respectively. More so, ZEN concentrations in summer (7.75 to 97.18 µg/kg) were higher than in winter (5.20 to 15.90 µg/kg). A similar observation was also noted for ZEN in Limpopo (7.80 to 97.18 µg/kg) and Free State (5.20 to 15.90 µg/kg). These findings were confirmed via Welch and Brown-Forsythe tests with significantly (p ≤ 0.05) higher mycotoxin levels produced by fungal strains obtained in samples during summer than those in winter. In contrast, the concentrations of mycotoxins produced by the fungal species from both provinces were not significantly (p > 0.05) different.

Citrus flavonoids against Fusarium verticillioides in post-harvest maize: Minimization of fumonisins and alteration of fungal ultrastructure

AIMS

To minimize fumonisins (FBs) accumulation by Fusarium verticillioides in post-harvest maize, using flavonoids obtained from citrus residues: naringin (NAR), neohesperidin (NEO), quercetin (QUER), and its mixtures.

METHODS AND RESULTS

Response surface methodology with Box-Behnken design was applied in maize at 0.98 and 0.95 a_w . The optimal mixture found, composed of 0.40 mmol kg^-1  NAR, 0.16 mmol kg^-1  NEO and 0.37 mmol kg^-1 QUER, reduced the accumulation of FBs B1, B2, and B3 by 88 ± 6%, 90 ± 6% and 85 ± 5%, respectively, when applied to maize at 0.98 a_w . The mentioned mixture led to a 54 ± 9% reduction of fumonisin B1 accumulation in maize adjusted to 0.95 a_w . These flavonoids applied individually and as a mixture, affected the structure of both the cell wall and the cytoplasm of F. verticillioides. The cell wall lost rigidity and the cells appeared highly deformed, with ruptured plasmalemma and disrupted endomembranes.

CONCLUSIONS

It was possible to diminish the accumulation of FBs in maize by a highly toxigenic Fusarium strain, producing severe damage to its ultrastructure.

SIGNIFICANCE AND IMPACT OF STUDY

The results indicate the possible use of flavonoids from citrus industry residues as natural and environmentally friendly antifungal agents to restrain the accumulation of FBs in stored maize.

Toxic Effect of Aflatoxins in Dogs Fed Contaminated Commercial Dry Feed: A Review

Since its first patent (1897), commercial dry feed (CDF) for dogs has diversified its formulation to meet the nutritional needs of different breeds, age, or special conditions and establish a foundation for integration of these pets into urban lifestyles. The risk of aflatoxicosis in dogs has increased because the ingredients used to formulate CDF have also proliferated, making it difficult to ensure the quality required of each to achieve the safety of the entire CDF. This review contains a description of the fungi and aflatoxins detected in CDF and the ingredients commonly used for their formulation. The mechanisms of action and pathogenic effects of aflatoxins are outlined; as well as the clinical findings, and macroscopic and microscopic lesions found in aflatoxicosis in dogs. In addition, alternatives for diagnosis, treatment, and control of aflatoxins (AF) in CDF are analyzed, such as biomarkers of effect, improvement of blood coagulation, rate of elimination of AF, control of secondary infection, protection of gastric mucosa, reduction of oxidative stress, use of chemo-protectors, sequestrants, grain-free CDF, biocontrol, and maximum permitted limits, are also included.

AlternariaMycotoxins in Food and Feed: An Overview

Alternariais one of the major mycotoxigenic fungal genera with more than 70 reported metabolites.Alternariamycotoxins showed notably toxicity, such as mutagenicity, carcinogenicity, induction of DNA strand break, sphingolipid metabolism disruption, or inhibition of enzymes activity and photophosphorylation. This review reports on the toxicity, stability, metabolism, current analytical methods, and prevalence ofAlternariamycotoxins in food and feed through the most recent published research. Half of the publications were focused on fruits, vegetables, and derived products—mainly tomato and apples—while cereals and cereal by-products represented 38%. The most studied compounds were alternariol, alternariol methyl ether, tentoxin, and tenuazonic acid, but altenuene, altertoxins (I, II, and III), and macrosporin have been gaining importance in recent years. Solid-liquid extraction (50%) with acetonitrile or ethyl acetate was the most common extraction methodology, followed by QuEChERS and dilution-direct injection (both 14%). High- and ultraperformance liquid chromatography coupled with tandem mass spectrometry was the predominant determination technique (80%). The highest levels of alternariol and alternariol methyl ether were found in lentils, oilseeds, tomatoes, carrots, juices, wines, and cereals. Tenuazonic acid highest levels were detected in cereals followed by beer, while alternariol, alternariol methyl ether, tenuazonic acid, and tentoxin were found in legumes, nuts, and oilseeds.

Systemic Infection of Maize, Sorghum, Rice, and Beet Seedlings with Fumonisin-Producing and Nonproducing Fusarium verticillioides Strains

Two fumonisin-nonproducing strains of Fusarium verticillioides and their fumonisin producing progenitors were tested for aggressiveness toward maize, sorghum, rice, and beetroot seedlings grown under greenhouse conditions. None of the plants showed obvious disease symptoms after root dip inoculation. Fungal biomass was determined by species-specific real-time PCR. No significant (P = 0.05) differences in systemic colonization were detected between the wild type strains and mutants not producing fumonisins. F. verticillioides was not detected in any of the non-inoculated control plants. The fungus grew from roots to the first two internodes/leaves of maize, rice and beet regardless of fumonisin production. The systemic growth of F. verticillioides in sorghum was limited. The results showed that fumonisin production was not required for the infection of roots of maize, rice and beet by F. verticillioides.