Beauvericin-induced channels in ventricular myocytes and liposomes

Computational Applications: Beauvericin from a Mycotoxin into a Humanized Drug

Drug discovery was initially attributed to coincidence or experimental research. Historically, the traditional approaches were complex, lengthy, and expensive, entailing costly random screening of synthesized compounds or natural products coupled with in vivo validation largely depending on the availability of appropriate animal models. Currently, in silico modeling has become a vital tool for drug discovery and repurposing. Molecular docking and dynamic simulations are being used to find the best match between a ligand and a molecule, an approach that could help predict the biomolecular interactions between the drug and the target host. Beauvericin (BEA) is an emerging mycotoxin produced by the entomopathogenic fungus Beauveria bassiana, being originally studied for its potential use as a pesticide. BEA is now considered a molecule of interest for its possible use in diverse biotechnological applications in the pharmaceutical industry and medicine. In this manuscript, we provide an overview of the repurposing of BEA as a potential therapeutic agent for multiple diseases. Furthermore, considerable emphasis is given to the fundamental role of in silico techniques to (i) further investigate the activity spectrum of BEA, a secondary metabolite, and (ii) elucidate its mode of action.

Endophytic Alternaria and Fusarium species associated to potato plants (Solanum tuberosum L.) in Iran and their capability to produce regulated and emerging mycotoxins

Endophytic fungi live inside virtually every plant species, without causing any apparent disease or damage to the host. Nevertheless, under particular conditions, mutualistic lifestyle of endophytes may change to pathogenic. In this study, the biodiversity of Alternaria and Fusarium species, the two most abundant endophytic fungi isolated from healthy potato plants in two climatically different regions of Iran, Ardebil in the north-west and Kerman in the south-east, was investigated. Seventy-five Fusarium strains and 83 Alternaria strains were molecularly characterized by multi-locus gene sequencing. Alternaria strains were characterized by the sequences of gpd and caM gene fragments and the phylogenetic tree was resolved in 3 well-separated clades. Seventy-three strains were included in the clade A, referred as Alternaria section, 6 strains were included in clade B, referred as Ulocladioides section, and 4 strains were included in clade C, referred as Infectoriae section. Fusarium strains, identified by sequencing the translation elongation factor 1α (tef1), β-tubulin (tub2) and internal transcribed spacer (ITS) genomic regions, were assigned to 13 species, viz. F. brachygibosum, F. clavum, F. equiseti, F. flocciferum, F. incarnatum, F. nirenbergiae, F. nygamai, F. oxysporum, F. proliferatum, F. redolens, F. sambucinum, F. solani and F. thapsinum. Twenty-six selected strains, representative of F. equiseti, F. nirenbergiae, F. oxysporum, F. nygamai, F. proliferatum, and F. sambucinum, were also tested for production of the mycotoxins deoxynivalenol (DON), nivalenol (NIV), diacetoxyscirpenol (DAS), T-2 toxin (T-2), beauvericin (BEA), enniatins (ENNs), fumonisins (FBs), fusaric acid (FA) and moniliformin (MON). None of the tested strains produced trichothecene toxins (DON, NIV, DAS and T-2). Two out of 2 F. equiseti isolates, 1/6 F. oxysporum, 1/3 F. proliferatum, and 1/9 F. nygamai did not produce any of the tested toxins; the rest of strains produced one or more BEA, ENNs, FBs, FA and MON toxins. The most toxigenic strain, F. nygamai ITEM-19012, produced the highest quantities of FBs (7946, 4693 and 4333 μg/g of B1, B2, and B3 respectively), along with the highest quantities of both BEA (4190 μg/g) and MON (538 μg/g). These findings suggest that contamination of potato tubers with mycotoxins in the field or at post-harvest, due to a change in lifestyle of endophytic microflora, should be carefully considered and furtherly investigated.

Fungal Species and Mycotoxins Associated with Maize Ear Rots Collected from the Eastern Cape in South Africa

Maize production in South Africa is concentrated in its central provinces. The Eastern Cape contributes less than 1% of total production, but is steadily increasing its production and has been identified as a priority region for future growth. In this study, we surveyed ear rots at maize farms in the Eastern Cape, and mycotoxins were determined to be present in collected samples. Fungal isolations were made from mouldy ears and species identified using morphology and DNA sequences. Cladosporium, Diplodia, Fusarium and Gibberella ear rots were observed during field work, and of these, we collected 78 samples and isolated 83 fungal strains. Fusarium was identified from Fusarium ear rot (FER) and Gibberella ear rot (GER) and Stenocarpella from Diplodia ear rot (DER) samples, respectively. Using LC-MS/MS multi-mycotoxin analysis, it was revealed that 83% of the collected samples contained mycotoxins, and 17% contained no mycotoxins. Fifty percent of samples contained multiple mycotoxins (deoxynivalenol, 15-acetyl-deoxynivalenol, diplodiatoxin and zearalenone) and 33% contained a single mycotoxin. Fusarium verticillioides was not isolated and fumonisins not detected during this survey. This study revealed that ear rots in the Eastern Cape are caused by a wide range of species that may produce various mycotoxins.

On the Potential Role of the (Pseudo-) Jahn-Teller Effect in the Membrane Transport Processes: Enniatin B and Beauvericin

The molecular structure of mycotoxins enniatin B and beauvericin, which are used as ionophores, was studied using density functional theory in various symmetry groups and singly charged states. We have shown that the charge addition or removal causes significant structural changes. Unlike the neutral C3 molecules, the stability of the charged C1 structures was explained by the Jahn-Teller or Pseudo-Jahn-Teller effect. This finding agrees with the available experimental X-ray structures of their metal complexes where electron density transfer from the metal can be expected. Hence, the membrane permeability of metal sandwich-structure complexes possessing antimicrobial activities is modulated by the conformational changes.

Beauvericin (BEA) and enniatin B (ENNB)-induced impairment of mitochondria and lysosomes - Potential sources of intracellular reactive iron triggering ferroptosis in Atlantic salmon primary hepatocytes

Beauvericin (BEA) and enniatin B (ENNB) are emerging mycotoxins frequently detected in plant-based fish feed. With ionophoric properties, they have shown cytotoxic potential in mammalian models. Sensitivity in fish is still largely unknown. Primary hepatocytes isolated from Atlantic salmon (Salmo salar) were used as a model and exposed to BEA and ENNB (0.05-10 μM) for 48 h. Microscopy, evaluation of cell viability, total ATP, total H₂O₂, total iron content, total Gpx enzyme activity, and RNA sequencing were used to characterize the toxicodynamics of BEA and ENNB. Both mycotoxins became cytotoxic at ≥ 5 μM, causing condensation of the hepatocytes followed by formation of blister-like protrusions on the cell's membrane. RNA sequencing analysis at sub-cytotoxic levels indicated BEA and ENNB exposed hepatocytes to experience increased energy expenditure, elevated oxidative stress, and iron homeostasis disturbances sensitizing the hepatocytes to ferroptosis. The present study provides valuable knowledge disclosing the toxic action of these mycotoxins in Atlantic salmon primary hepatocytes.

Mycotoxin-mixture assessment in mother-infant pairs in Nigeria: From mothers' meal to infants' urine

Exposure to food and environmental contaminants is a global environmental health issue. In this study, innovative LC-MS/MS approaches were applied to investigate mycotoxin co-exposure in mother-infant pairs (n = 23) by analyzing matched plate-ready food, breast milk and urine samples of mothers and their exclusively breastfed infants. The study revealed frequent co-occurrence of two to five mycotoxins. Regulated (e.g. aflatoxins, deoxynivalenol and ochratoxin A) and emerging mycotoxins (e.g. alternariol monomethyl ether and beauvericin) were frequently detected (3 %-89 % and 45 %-100 %), in at least one specimen. In addition, a moderate association of ochratoxin A in milk to urine of mothers (r = 0.47; p = 0.003) and infants (r = 0.52; p = 0.019) but no other significant correlations were found. Average concentration levels in food mostly did not exceed European maximum residue limits, and intake estimates demonstrated exposure below tolerable daily intake values. Infants were exposed to significantly lower toxin levels compared to their mothers, indicating the protective effect of breastfeeding. However, the transfer into milk and urine and the resulting chronic low-dose exposure warrant further monitoring. In the future, occurrence of mycotoxin-mixtures, and their combined toxicological effects need to be comprehensively considered and implemented in risk management strategies. These should aim to minimize early-life exposure in critical developmental stages.

Mycotoxin Production in Fusarium According to Contemporary Species Concepts

Fusarium is one of the most important genera of plant-pathogenic fungi in the world and arguably the world's most important mycotoxin-producing genus. Fusarium species produce a staggering array of toxic metabolites that contribute to plant disease and mycotoxicoses in humans and other animals. A thorough understanding of the mycotoxin potential of individual species is crucial for assessing the toxicological risks associated with Fusarium diseases. There are thousands of reports of mycotoxin production by various species, and there have been numerous attempts to summarize them. These efforts have been complicated by competing classification systems based on morphology, sexual compatibility, and phylogenetic relationships. The current depth of knowledge of Fusarium genomes and mycotoxin biosynthetic pathways provides insights into how mycotoxin production is distributedamong species and multispecies lineages (species complexes) in the genus as well as opportunities to clarify and predict mycotoxin risks connected with known and newly described species. Here, we summarize mycotoxin production in the genus Fusarium and how mycotoxin risk aligns with current phylogenetic species concepts.

Beauvericin potentiates the activity of pesticides by neutralizing the ATP-binding cassette transporters in arthropods

Multi-drug resistance is posing major challenges in suppressing the population of pests. Many herbivores develop resistance, causing a prolonged survival after exposure to a previously effective pesticide. Consequently, resistant pests reduce the yield of agricultural production, causing significant economic losses and reducing food security. Therefore, overpowering resistance acquisition of crop pests is a must. The ATP binding cassette transporters (ABC transporters) are considered as the main participants to the pesticide efflux and their neutralization will greatly contribute to potentiate failed treatments. Real-Time PCR analysis of 19 ABC transporter genes belonging to the ABCB, ABCC, ABCG, and ABCH revealed that a broad range of efflux pumps is activated in response to the exposure to pesticides. In this study, we used beauvericin (BEA), a known ABC transporters modulator, to resensitize different strains of Tetranychus urticae after artificial selection for resistance to cyflumetofen, bifenazate, and abamectin. Our results showed that the combinatorial treatment of pesticide (manufacturer's recommended doses) + BEA (sublethal doses: 0.15 mg/L) significantly suppressed the resistant populations of T. urticae when compared to single-drug treatments. Moreover, after selective pressure for 40 generations, the LC₅₀ values were significantly reduced from 36.5, 44.7, and 94.5 (pesticide) to 8.3, 12.5, and 23.4 (pesticide + BEA) for cyflumetofen, bifenazate, and abamectin, respectively. While the downstream targets for BEA are still elusive, we demonstrated hereby that it synergizes with sub-lethal doses of different pesticides and increases their effect by inhibiting ABC transporters. This is the first report to document such combinatorial activity of BEA against higher invertebrates paving the way for its usage in treating refractory cases of resistance to pesticides. Moreover, we demonstrated, for the first time, using in silico techniques, the higher affinity of BEA to ABC transformers subfamilies when compared to xenobiotics; thus, elucidating the pathway of the mycotoxin.

Study of enzymatic activity in human neuroblastoma cells SH-SY5Y exposed to zearalenone's derivates and beauvericin

Beauvericin (BEA), α-zearalenol (α-ZEL) and β-zearalenol (β-ZEL), are produced by several Fusarium species that contaminate cereal grains. These mycotoxins can cause cytotoxicity and neurotoxicity in various cell lines and they are also capable of produce oxidative stress at molecular level. However, mammalian cells are equipped with a protective endogenous antioxidant system formed by no-enzymatic antioxidant and enzymatic protective systems such as glutathione peroxidase (GPx), glutathione S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD). The aim of this study was evaluating the effects of α-ZEL, β-ZEL and BEA, on enzymatic GPx, GST, CAT and SOD activity in human neuroblastoma cells using the SH-SY5Y cell line, over 24 h and 48 h with different treatments at the following concentration range: from 1.56 to 12.5 μM for α-ZEL and β-ZEL, from 0.39 to 2.5 μM for BEA, from 1.87 to 25 μM for binary combinations and from 3.43 to 27.5 μM for tertiary combination. SH-SY5Y cells exposed to α-ZEL, β-ZEL and BEA revealed an overall increase in the activity of i) GPx, after 24 h of exposure up to 24-fold in individual treatments and 15-fold in binary combination; ii) GST after 24 h of exposure up to 10-fold (only in combination forms), and iii) SOD up to 3.5- and 5-fold in individual and combined treatment, respectively after 48 h of exposure. On the other hand, CAT activity decreased significantly in all treatments up to 92% after 24 h except for β-ZEL + BEA, which revealed the opposite.

Feedborne Mycotoxins Beauvericin and Enniatins and Livestock Animals

Mycotoxins are secondary metabolites produced by several species of fungi, including the Fusarium, Aspergillus, and Penicillium species. Currently, more than 300 structurally diverse mycotoxins are known, including a group called minor mycotoxins, namely enniatins, beauvericin, and fusaproliferin. Beauvericin and enniatins possess a variety of biological activities. Their antimicrobial, antibiotic, or ionoforic activities have been proven and according to various bioassays, they are believed to be toxic. They are mainly found in cereal grains and their products, but they have also been detected in forage feedstuff. Mycotoxins in feedstuffs of livestock animals are of dual concern. First one relates to the safety of animal-derived food. Based on the available data, the carry-over of minor mycotoxins from feed to edible animal tissues is possible. The second concern relates to detrimental effects of mycotoxins on animal health and performance. This review aims to summarize current knowledge on the relation of minor mycotoxins to livestock animals.

A Novel and Potentially MultifacetedDehydroascorbate Reductase Increasing theAntioxidant Systems Is Induced by Beauvericinin Tomato

Dehydroascorbate reductases (DHARs) are important enzymes that reconvert the dehydroascorbic acid (DHA) into ascorbic acid (ASC). They are involved in the plant response to oxidative stress, such as that induced by the mycotoxin beauvericin (BEA). Tomato plants were treated with 50 µM of BEA; the main antioxidant compounds and enzymes were evaluated. DHARs were analyzed in the presence of different electron donors by native and denaturing electrophoresis as well as by western blot and mass spectrometry to identify a novel induced protein with DHAR activity. Kinetic parameters for dehydroascorbate (DHA) and glutathione (GSH) were also determined. The novel DHAR was induced after BEA treatment. It was GSH-dependent and possessed lower affinity to DHA and GSH than the classical DHARs. Interestingly, the mass spectrometry analysis of the main band appearing on sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) revealed a chloroplast sedoheptulose 1,7-bisphosphatase, a key enzyme of the Calvin cycle, and a chloroplast mRNA-binding protein, suggesting that the DHA reducing capacity could be a side activity or the novel DHAR could be part of a protein complex. These results shed new light on the ascorbate-glutathione regulation network under oxidative stress and may represent a new way to increase the plant antioxidant defense system, plant nutraceutical value, and the health benefits of plant consumption.

Counteracting in Vitro Toxicity of the Ionophoric Mycotoxin Beauvericin-Synthetic Receptors to the Rescue

Beauvericin (BEA) and enniatins are toxic ionophoric cyclodepsipeptides that mainly occur in grains. As such, their presence in food commodities poses a concern for public health. To date, despite recent European Food Safety Authority emphasis on the need for more data to evaluate long-term toxicity effects, no suitable affinity reagents are available to detect the presence of BEA and derivatives in food samples. We here report on the synthesis of a small library of artificial receptors with varying cavity sizes and different hydrophobic building blocks. Immobilization of one of the receptors on solid support resulted in a strong retention of beauvericin, thus revealing promising properties as solid-phase extraction material for sample pretreatment. Furthermore, treatment of HepG2 cells with the most promising receptor markedly reduced beauvericin-induced cytotoxicity, hinting toward the possibility of using synthetic receptors as antidotes against ionophoric toxins.

Development of Sensitive and Reliable UPLC-MS/MS Methods for Food Analysis of Emerging Mycotoxins in China Total Diet Study

With the climatic changes that have taken place during the last decade, the spectrum of fungal pathogens as well as mycotoxins has considerably changed. As a result, some emerging mycotoxins have been shown to occur frequently in agricultural products. In this study, a sensitive and reliable method for the determination of 10 emerging mycotoxins (beauvericin, enniatin A, enniatin A1, enniatin B, enniatin B1, alternariol, alternariol monomethyl ether, altenuene, tentoxin, and tenuazonic acid) in 12 different food matrices (cereals, legumes, potatoes, meats, eggs, aquatic foods, dairy products, vegetables, fruits, sugars, beverages, and alcohol beverages) was developed and validated. After a simple extraction, a one-step sample clean-up by a HLB solid phase extraction (SPE) column was sufficient for all 12 food matrices prior to analysis with ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). Isotope internal standards ¹³C-TeA, TEN-d₃, and ¹³C-AFB2 were used for accurate quantification. Validation in terms of linearity, selectivity, sensitivity, accuracy, and precision (intra and inter-day variability) were evaluated for the 10 mycotoxins in all selected matrices. The sensitivity varied from 0.0004 to 0.3 ng mL^-1 (limits of detection) and from 0.002 to 0.9 ng mL^-1 (limits of quantitation). The recoveries of 10 mycotoxins in fortified samples were from 60.6% to 164% including very low spiking levels in all 12 food matrices, with relative standard deviations (RSDs) less than 12%. The proposed methodology was applied to the analysis of 60 samples collected from five provinces within the 6^th China Total Diet Study with the results discussed in detail. The advantages of sensitivity, accuracy, and robustness made it a powerful tool for emerging mycotoxin monitoring and dietary exposure assessment.

Food Safety and Climate Change. In: Kahime K, El Hidan MA, El Hiba O, Sereno D, Bounoua L, editors. Handbook of Research on Global Environmental Changes and Human Health. IGI Global; 2019. pp. 74-97. [DOI: 10.4018/978-1-5225-7775-1.ch005]

Mycotoxins are chemical compounds produced mainly by mounds of genera Aspergillus, Penicillium, and Fusarium on various grains and agricultural commodities at different stages in the field, before harvest, post-harvest, during processing, packaging, distribution, and storage. The production of mycotoxins depends on several environmental factors such as temperature and moisture. This chapter gives an overview about the major mycotoxins (e.g., aflatoxins, ochratoxin A, and Fusarium toxins), masked mycotoxins, and emerging mycotoxins. The toxicity of these mycotoxins and their negative economic impact was also discussed together with the effect of climate change on their production. A section on mycotoxins regulations by international agencies and organisms (WHO, FAO, EU, etc.) was discussed. Finally, the different strategies to reduce or eliminate the toxic effects of mycotoxins in contaminated foods and feeds by using chemical, physical, and biological/biotechnological methods or innovative approaches were explained.

A Review on the Synthesis and Bioactivity Aspects of Beauvericin, a Fusarium Mycotoxin

Beauvericin (BEA) is an emerging Fusarium mycotoxin that contaminates food and feeds globally. BEA biosynthesis is rapidly catalyzed by BEA synthetase through a nonribosomal, thiol-templated mechanism. This mycotoxin has cytotoxicity and is capable of increasing oxidative stress to induce cell apoptosis. Recently, large evidence further shows that this mycotoxin has a variety of biological activities and is being considered a potential candidate for medicinal and pesticide research. It is noteworthy that BEA is a potential anticancer agent since it can increase the intracellular Ca²⁺ levels and induce the cancer cell death through oxidative stress and apoptosis. BEA has exhibited effective antibacterial activities against both pathogenic Gram-positive and Gram-negative bacteria. Importantly, BEA exhibits an effective capacity to inhibit the human immunodeficiency virus type-1 integrase. Moreover, BEA can simultaneously target drug resistance and morphogenesis which provides a promising strategy to combat life-threatening fungal infections. Thus, in this review, the synthesis and the biological activities of BEA, as well as, the underlying mechanisms, are fully analyzed. The risk assessment of BEA in food and feed are also discussed. We hope this review will help to further understand the biological activities of BEA and cast some new light on drug discovery.

Comparative in vitro cytotoxicity of the emerging Fusarium mycotoxins beauvericin and enniatins to porcine intestinal epithelial cells

The emerging Fusarium mycotoxins beauvericin (BEA) and enniatin (ENN) A, ENN A1, ENN B and ENN B1 gain increasing interest due to their highly prevalent contamination of cereals and cereal products. After oral intake, the gastro-intestinal tract is the first possible site of interaction. In the present in vitro study, the relative cytotoxicity of these mycotoxins towards proliferating and differentiated intestinal porcine epithelial cells of the jejunum (IPEC-J2) was evaluated using flow cytometric viability analysis. IPEC-J2 cells showed the highest sensitivity to BEA and ENN A. In proliferating cells, incubation for 24h with 10 μM BEA caused complete disruption, while the viability percentage declined to 32% after 24h of incubation with 10 μM ENN A. ENN A1 and ENN B1 were less cytotoxic with 87% and 93% viable cells after 24h of incubation with 10 μM ENN A1 and B1, respectively. ENN B was the least cytotoxic since incubation at concentrations up to 100 μM resulted in 83% viable proliferating cells. The same trend was observed for differentiated cells. The limited in vitro cytotoxic effect of ENN B on intestinal cells corroborates previous in vivo findings in broiler chicken in which dietary ENN B had minimal effect on intestinal morphometry.

Fusarium Molds and Mycotoxins: Potential Species-Specific Effects

This review summarizes the information on biochemical and biological activity of the main Fusarium mycotoxins, focusing on toxicological aspects in terms of species-specific effects. Both in vitro and in vivo studies have centered on the peculiarity of the responses to mycotoxins, demonstrating that toxicokinetics, bioavailability and the mechanisms of action of these substances vary depending on the species involved, but additional studies are needed to better understand the specific responses. The aim of this review is to summarize the toxicological responses of the main species affected by Fusarium mycotoxins.

In vitro mechanisms of Beauvericin toxicity: A review

Beauvericin (BEA) is a mycotoxin produced by many species of fungus Fusarium and by Beauveria bassiana; BEA is a natural contaminant of cereals and cereals based products and possesses a wide variety of biological properties. The mechanism of action seems to be related to its ionophoric activity, that increases ion permeability in biological membranes. As a consequence, BEA causes cytotoxicity in several cell lines and is capable to produce oxidative stress at molecular level. Moreover, BEA is genotoxic (produces DNA fragmentation, chromosomal aberrations and micronucleus) and causes apoptosis with the involvement of mitochondrial pathway. However, several antioxidant mechanisms protect cells against oxidative stress produced by BEA. Despite its strong cytotoxicity, no risk assessment have been still carried out by authorities due to a lack of toxicity data, so research on BEA toxicological impact is still going on. This review reports information available regarding BEA mechanistic toxicology with the aim of updating information regarding last researches on this mycotoxin.

Emerging Mycotoxins: Beyond Traditionally Determined Food Contaminants

Modern analytical techniques can determine a multitude of fungal metabolites contaminating food and feed. In addition to known mycotoxins, for which maximum levels in food are enforced, also currently unregulated, so-called "emerging mycotoxins" were shown to occur frequently in agricultural products. The aim of this review is to critically discuss the relevance of selected emerging mycotoxins to food and feed safety. Acute and chronic toxicity as well as occurrence data are presented for enniatins, beauvericin, moniliformin, fusaproliferin, fusaric acid, culmorin, butenolide, sterigmatocystin, emodin, mycophenolic acid, alternariol, alternariol monomethyl ether, and tenuazonic acid. By far not all of the detected compounds are toxicologically relevant at their naturally occurring levels and are therefore of little or no health concern to consumers. Still, gaps in knowledge have been identified for several compounds. These gaps should be closed by the scientific community in the coming years to allow a proper risk assessment.

Emerging Fusarium and Alternaria Mycotoxins: Occurrence, Toxicity and Toxicokinetics

Emerging Fusarium and Alternaria mycotoxins gain more and more interest due to their frequent contamination of food and feed, although in vivo toxicity and toxicokinetic data are limited. Whereas the Fusarium mycotoxins beauvericin, moniliformin and enniatins particularly contaminate grain and grain-based products, Alternaria mycotoxins are also detected in fruits, vegetables and wines. Although contamination levels are usually low (µg/kg range), higher contamination levels of enniatins and tenuazonic acid may occasionally occur. In vitro studies suggest genotoxic effects of enniatins A, A1 and B1, beauvericin, moniliformin, alternariol, alternariol monomethyl ether, altertoxins and stemphyltoxin-III. Furthermore, in vitro studies suggest immunomodulating effects of most emerging toxins and a reproductive health hazard of alternariol, beauvericin and enniatin B. More in vivo toxicity data on the individual and combined effects of these contaminants on reproductive and immune system in both humans and animals is needed to update the risk evaluation by the European Food Safety Authority. Taking into account new occurrence data for tenuazonic acid, the complete oral bioavailability, the low total body clearance in pigs and broiler chickens and the limited toxicity data, a health risk cannot be completely excluded. Besides, some less known Alternaria toxins, especially the genotoxic altertoxins and stemphyltoxin III, should be incorporated in risk evaluation as well.

Occurrence, toxicity, bioaccessibility and mitigation strategies of beauvericin, a minor Fusarium mycotoxin

Emerging Fusarium mycotoxins include the toxic secondary metabolites fusaproliferin, enniatins, beauvericin (BEA), and moniliform. BEA is produced by some entomo- and phytopathogenic Fusarium species and occurs naturally on corn and corn-based foods and feeds infected by Fusarium spp. BEA has shown various biological activities (antibacterial, antifungal, and insecticidal) and possesses toxic activity, including the induction of apoptosis, increase cytoplasmic calcium concentration and lead to DNA fragmentation in mammalian cell lines. Cereals food processing has an important effect on mycotoxin stability, leading to less-contaminated food compared to the raw materials. Different industrial processes have shown to be effective practices to reduce BEA contents due to thermal food processing applied, such as cooking, boiling, baking, frying, roasting and pasteurization. Some studies demonstrated the capacity of lactic acid bacteria to reduce the presence of the BEA in model solution and in food chain through fermentation processes, modifying this mycotoxin in a less toxic derivate. Prebiotic and probiotic ingredient can modulate the bioaccessibility of BEA reducing the risk of intake of this minor Fusarium mycotoxin. This review summarizes the existing data on occurrence, toxicity and especially on BEA reduction strategies in food and feed such as chemical reduction, biocontrol and food processing.

Effect of Fusarium-Derived Metabolites on the Barrier Integrity of Differentiated Intestinal Porcine Epithelial Cells (IPEC-J2)

The human, animal and plant pathogen Fusarium, which contaminates agricultural commodities worldwide, produces numerous secondary metabolites. An example is the thoroughly-investigated deoxynivalenol (DON), which severely impairs gastrointestinal barrier integrity. However, to date, the toxicological profile of other Fusarium-derived metabolites, such as enniatins, beauvericin, moniliformin, apicidin, aurofusarin, rubrofusarin, equisetin and bikaverin, are poorly characterized. Thus we examined their effects—as metabolites alone and as metabolites in combination with DON—on the intestinal barrier function of differentiated intestinal porcine epithelial cells (IPEC-J2) over 72 h. Transepithelial electrical resistance (TEER) was measured at 24-h intervals, followed by evaluation of cell viability using neutral red (NR) assay. Enniatins A, A1, B and B1, apicidin, aurofusarin and beauvericin significantly reduced TEER. Moniliformin, equisetin, bikaverin and rubrofusarin had no effect on TEER. In the case of apicidin, aurofusarin and beauvericin, TEER reductions were further substantiated by the addition of otherwise no-effect DON concentrations. In all cases, viability was unaffected, confirming that TEER reductions were not due to compromised viability. Considering the prevalence of mycotoxin contamination and the diseases associated with intestinal barrier disruption, consumption of contaminated food or feed may have substantial health implications.

Toxicity of beauvericin on porcine oocyte maturation and preimplantation embryo development

Beauvericin (BEA) is one of many toxins produced by Fusarium species that contaminate feed materials. The aim of this study was to assess its effects on porcine oocyte maturation and preimplantation embryo development. Cumulus-oocyte-complexes and developing embryos were exposed to BEA and cultured until the blastocyst stage. Cumulus cells, oocytes and embryos were examined for viability, progesterone synthesis, multidrug resistance protein (MDR1), ATP content and gene expression related to MDR1 function, oxidative phosphorylation, steroidogenesis and apoptosis. BEA was toxic in embryos, oocytes and cumulus cells at concentrations exceeding 0.5μM, and embryos were most vulnerable after the four-cell stage. Since BEA exerted different effects in embryos, oocytes and cumulus cells, the toxic mechanism is suggested to involve different pathways. Currently there are no consistent data on adverse effects of BEA in pig farms.

Oxidative stress generated during monensin treatment contributes to altered Toxoplasma gondii mitochondrial function

The ionophore monensin displays potent activities against several coccidian parasites of veterinary and medical importance including the opportunistic pathogen of humans, Toxoplasma gondii. While monensin is used widely in animals, toxicity impedes its use in humans. Nonetheless, given its potency, understanding its mode of action would reveal vulnerable aspects of the parasite that can be exploited for drug development. We previously established that monensin induces Toxoplasma to undergo cell cycle arrest and an autophagy-like cell death. Interestingly, these effects are dependent on the mitochondrion-localized TgMSH-1 protein, suggesting that monensin disrupts mitochondrial function. We demonstrate that monensin treatment results in decreased mitochondrial membrane potential and altered morphology. These effects are mitigated by the antioxidant compound N-acetyl-cysteine suggesting that monensin causes an oxidative stress, which was indeed the case based on direct detection of reactive oxygen species. Moreover, over-expression of the antioxidant proteins glutaredoxin and peroxiredoxin 2 protect Toxoplasma from the deleterious effects of monensin. Thus, our studies show that the effects of monensin on Toxoplasma are due to a disruption of mitochondrial function caused by the induction of an oxidative stress and implicate parasite redox biology as a viable target for the development of drugs against Toxoplasma and related pathogenic parasites.

Beauvericin Inhibits Neuromuscular Transmission and Skeletal Muscle Contractility in Mouse Hemidiaphragm Preparation

The effects of Beauvericin (BEA) produced by the fungusBeauveria bassianaandFusariumsp. on neuromuscular transmission and contractility were determined in an isolated neuromuscular mouse hemidiaphragm preparation. BEA (5 µM) significantly inhibits indirectly elicited twitch amplitude. At higher concentrations (7.5 and 10 µM), BEA produces a significant reduction of directly elicited, or complete block of indirectly evoked, muscle contraction. BEA also appears to be myotoxic, as indicated by a slowly developing muscle contracture. Development of neuromuscular blockade and contracture is concentration dependent. BEA acted by presynaptically depressing spontaneous acetylcholine release as indicated by the reduction in the frequency of spontaneous miniature endplate potentials (MEPPs), while the membrane potential of muscle fibers remained unchanged. At higher concentrations (7.5 and 10 µM), BEA progressively reduces or completely blocks MEPPs and EPPs amplitudes. Changes in MEPPs and EPPs are associated with substantial depolarization of muscle fibers when exposed to 7.5 and 10 µM of BEA. These results indicate that BEA has neurotoxic and myotoxic effects, which overlap in a narrow range of concentrations.

Beauvericin-induced cytotoxicity via ROS production and mitochondrial damage in Caco-2 cells

The cytotoxicity of beauvericin (BEA) on human colon adenocarcinoma (Caco-2) cells was studied as a function of time. Moreover, the oxidative damage and cell death endpoints were monitored after 24, 48 and 72 h. After BEA exposure, the IC₅₀ values ranged from 1.9 ± 0.7 to 20.6 ± 6.9 μM. A decrease in reduced glutathione (GSH; 31%) levels, as well as an increase in oxidized glutathione (GSSG, 20%) was observed. In the presence of BEA, reactive oxygen species (ROS) level was highly increased at an early stage with the highest production of 2.0-fold higher than the control that was observed at 120 min. BEA induced cell death by mitochondria-dependent apoptotic process with loss of the mitochondrial membrane potential (ΔΨm; 9% compared to the control), increase in LPO level (from 120% to 207% compared to the control) and reduced G0/G1 phase, with an arrest in G2/M, in a dose and time-dependent manner. Cell proliferation, apoptosis and ΔΨm determined, were in a dose- time-dependent manner. Moreover, DNA damage was observed after 12.0 μM concentration. This study demonstrated that oxidative stress is one of the mechanism involved in BEA toxicity, moreover apoptosis induction and loss of ΔΨm contribute to its cytotoxicity in Caco-2 cells.

Destruxins: fungal-derived cyclohexadepsipeptides with multifaceted anticancer and antiangiogenic activities

Destruxins (Dtx) are secondary metabolites of the entomopathogenic fungus Metarhizium anisopliae. Recently, Dtx came into focus of interest as anticancer therapeutics. However, data on human and especially on cancer cells are fragmentary. In order to successfully establish novel anticancer therapeutics, a broad knowledge on the cellular and molecular mechanisms underlying their activity is essential. Consequently, this study aimed to investigate the impact of the most common Dtx derivatives A, B and E on human cancer cell growth and survival with a focus on colon cancer cell models. Summarizing, the experimental data showed that (i) Dtx A and B exert potent antiproliferative activity in the micromolar and Dtx E in the nanomolar range in KB-3-1, A549, CaCo-2, and especially in HCT116 colon cancer cells, (ii) all three Dtx derivatives cause imbalance of cell cycle distribution, (iii) their cytostatic/cytotoxic effects are widely p53-independent but reduced by p21- and bax-deletion, respectively, (iv) cytotoxicity is based on intrinsic apoptosis induction and associated with phosphoinositide-3-kinase (PI3K)/Akt pathway inhibition, (v) anticancer activity of Dtx E but not Dtx A and B involves disturbance of the intracellular redox balance, (vi) Dtx inhibit the migration and tube formation of human endothelial cells indicating antiangiogenic potential, and (vii) all three Dtx derivatives possess ionophoric properties not differing in conductivity, ion selectivity and single channel kinetics. Thus, Dtx represent feasible, multifunctional anticancer drug candidates for preclinical development especially against colorectal cancer.

Beauvericin, a bioactive compound produced by fungi: a short review

Beauvericin is a cyclic hexadepsipeptide mycotoxin, which has insecticidal, antimicrobial, antiviral and cytotoxic activities. It is a potential agent for pesticides and medicines. This paper reviews the bioactivity, fermentation and biosynthesis of the fungal product beauvericin.

Beauvericin induced erythrocyte cell membrane scrambling

Beauvericin is a mycotoxin with antiviral, antibacterial, nematicidal, insecticidal, cytotoxic, and apoptotic activity. Similar to nucleated cells erythrocytes may undergo suicidal death or eryptosis, which is characterized by cell shrinkage and phosphatidylserine exposure at the erythrocyte surface. Eryptosis may be triggered by energy depletion leading to increase of cytosolic Ca²+ activity. The present study thus explored whether beauvericin is able to trigger eryptosis and influence eryptosis following energy depletion. Cell membrane scrambling was estimated from binding of annexin V to phosphatidylserine at the erythrocyte surface, cell volume from forward scatter in FACS analysis, cytosolic Ca²+ concentration from Fluo3 fluorescence, cytosolic ATP concentration from a luciferase-assay and ion channel activity with whole cell patch clamp. Exposure to beauvericin (≥ 5 μM) significantly decreased erythrocyte ATP concentration and increased cytosolic Ca²+ concentration as well as annexin V-binding. The effect of beauvericin on annexin V binding was significantly blunted by removal of extracellular Ca²+. Glucose depletion (48 h) was followed by, increase of Fluo3 fluorescence, decrease of forward scatter and increase of annexin V-binding. Beauvericin (≥ 1 μM) augmented the effect of glucose withdrawal on Fluo3 fluorescence and annexin V-binding, but significantly blunted the effect of glucose withdrawal on forward scatter, an effect paralleled by inhibition of Ca²+ activated K+ channels. The present observations disclose novel effects of beauvericin, i.e. stimulation of Ca²+ entry with subsequent cell membrane scrambling and inhibition of Ca²+ activated K+ channels with blunting of cell shrinkage.

Evaluation of beauvericin genotoxicity with the chromosomal aberrations, sister-chromatid exchanges and micronucleus assays

Beauvericin, a naturally occurring contaminants of food and feeds, has been implicated in several mycotoxicoses; however, there is little information on its genotoxicity. Therefore, the genotoxic and cytotoxic effects of beauvericin in in vitro cultures of human lymphocytes were investigated with chromosome aberrations (CAs), sister-chromatid exchanges (SCEs), micronuclei (MN) as well as mitotic, proliferative and nuclear division indices. Beauvericin caused a significant concentration-dependent increase in chromosomal aberrations, sister-chromatid exchanges and micronuclei. It also significantly decreased the mitotic index at the two highest concentrations. However, no significant change in the proliferative and nuclear division indices was found. The results indicated that BEA is genotoxic to human lymphocytes in vitro.

Beauvericin and ochratoxin A genotoxicity evaluated using the alkaline comet assay: single and combined genotoxic action

This study was aimed at investigating the genotoxic potential of single beauvericin (BEA) and ochratoxin A (OTA) as well as their interaction in porcine kidney epithelial PK15 cells and human leukocytes using the alkaline comet assay. IC(50) of BEA (5.0 +/- 0.6) and OTA (15.8 +/- 1.5) estimated by MTT reduction assay shows that BEA is three times more toxic than OTA. BEA (0.1 and 0.5 microM) and OTA (1 and 5 microM) were applied alone or in combination of these concentrations for 1 and 24 h in PK15 cells and human leukocytes. Genotoxicity of these toxins to PK15 cells was time- and concentration dependent. After 1 h, significant increase in tail length, tail intensity, tail moment, and abnormal sized tails (AST) was noted upon exposure to 1 muM of OTA alone and BEA + OTA combinations. Single BEA (0.5 microM) and OTA (1 and 5 microM) and their combinations evoked significant DNA damage in PK15 cells, considering all comet tail parameters measured after 24 h of treatment. Human leukocytes were slightly concentration but not time dependent. After 1 h of exposure, there were no significant changes in the tail length. Tail intensity, tail moment, and/or incidence of AST were significantly higher in cells treated with single OTA or BEA and their combinations than in control cells. DNA damage in leukocytes was significantly higher after 24 h of exposure to single toxins and their combinations, considering all comet tail parameters, but these changes were less pronounced than in PK15 cells. Combined toxins showed additive and synergistic effects in PK15 cells, while only additive effects were observed in human leukocytes. Combined prolonged exposure to BEA and OTA in subcytotoxic concentrations through food consumption could induce DNA damage contributing to the carcinogenicity in animals and humans.

Overview of analytical methods for beauvericin and fusaproliferin in food matrices

In recent years consumers and the scientific community have become increasingly interested in food safety, making it a major focus among the objectives of the international institutions responsible for food safety monitoring, e.g. the European Union or the EFSA. Aspects attracting much attention are the colonization of food by microscopic fungi which, under aerobic conditions, produce toxic secondary metabolites known as mycotoxins, and the accumulation of these toxins in the food chain. Numerous studies of surveillance, detoxification, prevention, and toxicological aspects reported in the literature mostly concentrate on major mycotoxins such as aflatoxins, ochratoxin A, trichothecenes, and fumonisins; studies on toxic secondary metabolites of mycotoxins are less common or are only just beginning. Among the molecules of interest, the family of beauvericin and fusaproliferin is certainly the most interesting. The objective of this review is to summarize reported data and the methods used to extract and quantify beauvericin and fusaproliferin in food matrices.