Toxicity of beauvericin on porcine oocyte maturation and preimplantation embryo development

Exploration of beauvericin's toxic effects and mechanisms in human astrocytes and N-acetylcysteine's protective role

Beauvericin (BEA) is a newly identified mycotoxin produced by various Fusarium species, and its contamination in food and animal feed is widespread globally. This mycotoxin demonstrates cytotoxic effects by inducing oxidative stress in multiple models. Furthermore, evidence indicates that BEA possesses diverse toxic activities, making it a promising candidate for toxicological research. Recent studies have highlighted the ability of BEA to traverse the blood-brain barrier, suggesting its potential neurotoxicity. However, limited information is available regarding the neurotoxic effects of BEA on human astrocytes. Therefore, this study aimed to assess the neurotoxic effects of BEA on the Gibco® Human Astrocyte (GHA) cell line and elucidate the underlying mechanisms. Additionally, the study aimed to investigate the protective effects of the antioxidant N-acetylcysteine (NAC) against BEA-induced toxicity. The data show that exposure to BEA within the 2.5-15 μM concentration range resulted in concentration-dependent cytotoxicity. BEA-treated cells exhibited significantly increased levels of reactive oxygen species (ROS), while intracellular glutathione (GSH) content was significantly reduced. Western blot analysis of cells treated with BEA revealed altered protein levels of Bax, cleaved caspase-9, and caspase-3, along with an increased Bax/Bcl-2 ratio, indicating the induction of apoptosis. Additionally, BEA exposure triggered antioxidant responses, as evidenced by increased protein expression of Nrf2, HO-1, and NQO1. Significantly, pretreatment with NAC partially attenuated the significant toxic effects of BEA. In conclusion, our findings suggest that BEA-induced cytotoxicity in GHA cells involves oxidative stress-associated apoptosis. Furthermore, NAC demonstrates potential as a protective agent against BEA-induced oxidative damage.

2-bromoacetamide exposure impairs oocyte maturation in mice and humans primarily via disrupting the cytoskeleton

2-bromoacetamide (BAcAm) is an emerging class of unregulated disinfection by-products (DBPs), with potent cytogenetic and developmental toxicity in animals. However, whether BAcAm exerts toxic effects on mammalian oocyte quality remains to be elucidate. In this research, we investigated the effect of BAcAm on mouse and human oocyte maturation with an in vitro culture system. Our results revealed that BAcAm exposure hindered the extrusion of the first polar body, disrupted the spindle organization and reduced the competence of embryo development after fertilization in the mouse oocytes. Results of single-cell RNA sequencing (scRNA-seq) showed that 605 differentially expressed genes (DEGs) were identified in the BAcAm exposed mouse oocytes, among which 366 were up-regulated and 239 were down-regulated. Gene Ontology (GO) analysis further revealed that DEGs were mainly enriched in mitochondrial functions, oxidative stress, cytoskeleton, endoplasmic reticulum (ER), Golgi and protein synthesis, DNA damage and apoptosis. We then conducted further tests in these aspects and discovered that BAcAm exposure principally perturbed the function of microtubule and actin cytoskeleton. This finding was confirmed in human oocytes. Overall, our data suggest that BAcAm exposure disturbs the cytoskeleton function, thus impairing oocyte maturation. These data, for the first time, provide a comprehensive view for the toxic effects of BAcAm on oocyte maturation.

Toxicity of the emerging mycotoxins beauvericin and enniatins: A mini-review

Beauvericin and enniatins, emerging mycotoxins produced mainly by Fusarium species, are natural contaminants of cereals and cereal products. These mycotoxins are cyclic hexadepsipeptides with ionophore properties and their toxicity mechanism is related to their ability to transport cations across the cell membrane. Beauvericin and enniatins are cytotoxic, as they decrease cell viability, promote cell cycle arrest, and increase apoptosis and the generation of reactive oxygen species in several cell lines. They also cause changes at the transcriptomic level and have immunomodulatory effects in vitro and in vivo. Toxicokinetic results are scarce, and, despite its proven toxic effects in vitro, no regulation or risk assessment has yet been performed due to a lack of in vivo data. This mini-review aims to report the information available in the literature on studies of in vitro and in vivo toxic effects with beauvericin and enniatins, which are mycotoxins of increasing interest to animal and human health.

Effects of beauvericin on the blood cells of Bombyx mori

In this study, silkworms were treated by injection of the bioactive depsipeptide beauvericin (BEA) to explore its effect on the cellular immunity of larvae of the silkworm Bombyx mori. The results showed that: The LC50 of BEA for silkworms on the 3rd day of the 4th instar was 362.36 µM. The total count of circulating hemocytes in the silkworms decreased at 12 h after injection with 350 µM BEA, and reached the minimum value at 72 h post-treatment; at 48 h post-treatment, a large number of nodules formed by the aggregation of blood cells of the silkworms were observed under the light microscope. The survival rate of hemocytes in the larvae treated with BEA was significantly reduced in a dose-dependent manner in vivo and in vitro. The encapsulation of Q-Sepharose Fast Flow (QFF) gel particles by hemocytes in the treatment group was significantly higher than that in the control group at 1.5 h and 3 h post-treatment (P < 0.05). Moreover, the melanization ratio of QFF gel particles kept increasing with treatment time. The melanization rate at 24 h after treatment was significantly higher than that at other times (P < 0.05), reaching 55.33 %. Under the scanning electron microscope, BEA-treated larvae showed protrusions on the surface of their blood cells in vivo. Under the transmission electron microscope, it was observed that silkworm hemocytes were vacuolated. This study demonstrated that BEA had an effect on the blood cells of silkworms, and has thrown some light on the inhibitory effect and mechanism of BEA on insect cellular immunity.

Fertility loss: negative effects of environmental toxicants on oogenesis

There has been a global decline in fertility rates, with ovulatory disorders emerging as the leading cause, contributing to a global lifetime infertility prevalence of 17.5%. Formation of the primordial follicle pool during early and further development of oocytes after puberty is crucial in determining female fertility and reproductive quality. However, the increasing exposure to environmental toxins (through occupational exposure and ubiquitous chemicals) in daily life is a growing concern; these toxins have been identified as significant risk factors for oogenesis in women. In light of this concern, this review aims to enhance our understanding of female reproductive system diseases and their implications. Specifically, we summarized and categorized the environmental toxins that can affect oogenesis. Here, we provide an overview of oogenesis, highlighting specific stages that may be susceptible to the influence of environmental toxins. Furthermore, we discuss the genetic and molecular mechanisms by which various environmental toxins, including metals, cigarette smoke, and agricultural and industrial toxins, affect female oogenesis. Raising awareness about the potential risks associated with toxin exposure is crucial. However, further research is needed to fully comprehend the mechanisms underlying these effects, including the identification of biomarkers to assess exposure levels and predict reproductive outcomes. By providing a comprehensive overview, this review aims to contribute to a better understanding of the impact of environmental toxins on female oogenesis and guide future research in this field.

Emerging mycotoxins induce hepatotoxicity in pigs' precision-cut liver slices and HepG2 cells

Emerging mycotoxins are currently gaining more attention due to their high frequency of contamination in foods and grains. However, most data available in the literature are in vitro, with few in vivo results that prevent establishing their regulation. Beauvericin (BEA), enniatins (ENNs), emodin (EMO), apicidin (API) and aurofusarin (AFN) are emerging mycotoxins frequently found contaminating food and there is growing interest in studying their impact on the liver, a key organ in the metabolization of these components. We used an ex vivo model of precision-cut liver slices (PCLS) to verify morphological and transcriptional changes after acute exposure (4 h) to these mycotoxins. The human liver cell line HepG2 was used for comparison purposes. Most of the emerging mycotoxins were cytotoxic to the cells, except for AFN. In cells, BEA and ENNs were able to increase the expression of genes related to transcription factors, inflammation, and hepatic metabolism. In the explants, only ENN B1 led to significant changes in the morphology and expression of a few genes. Overall, our results demonstrate that BEA, ENNs, and API have the potential to be hepatotoxic.

Environment to embryo: intersections of contaminant exposure and preimplantation embryo development in agricultural animals

Environmental impacts on reproductive function are well documented in humans, yet little information is known about effects on large animals. The interface of environment and reproduction has evolved prudently with a concerted effort to ensure global food sustainability tightly integrated with application of technological advances in agriculture production that include nutrient and resource management. Exposure to environmental toxicants through chemical pesticide application and industry practices have coincided with a decline in cattle and human fertility. The increased adoption of agriculture animals for human biomedical models further emphasizes the importance of understanding the consequences of livestock exposure to environmentally and physiologically relevant levels of contaminants to preimplantation embryo development. In addition, increased awareness of paternal contributions to the early embryo that include both genetic and non-genetic factors support the need to define environmental interactions from gamete to genome. Herein we summarize current knowledge of common environmental contaminants on reproductive function including direct and indirect effects on embryo development success in livestock. Information obtained from a diverse number of species including humans is presented to illustrate gaps in knowledge within livestock directly pertaining to agriculture success, sustainability, clinical practice and biomedical research.

Mycotoxins in Maize Silage from China in 2019

Animal feed (including forage and silage) can be contaminated with mycotoxins. Here, 200 maize silage samples from around China were collected in 2019 and analyzed for regulated mycotoxins, masked mycotoxins (deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, and deoxynivalenol-3-glucoside), and emerging mycotoxins (beauvericin, enniatins, moniliformin, and alternariol). Deoxynivalenol and zearalenone were detected in 99.5% and 79.5% of the samples, respectively. Other regulated mycotoxins were detected in fewer samples. The highest deoxynivalenol and zearalenone concentrations were 3600 and 830 μg/kg, respectively. The most commonly detected masked mycotoxin was 15-acetyldeoxynivalenol, which was detected in 68.5% of the samples and had median and maximum concentrations of 61.3 and 410 μg/kg, respectively. The emerging mycotoxins beauvericin, alternariol, enniatin A, enniatin B1, and moniliformin were detected in 99.5%, 85%, 80.5%, 72.5%, and 44.5%, respectively, of the samples but at low concentrations (medians <25 μg/kg). The samples tended to contain multiple mycotoxins, e.g., the correlation coefficients for the relationships between the concentrations of beauvericin and deoxynivalenol, deoxynivalenol and zearalenone, and zearalenone and beauvericin were 1.0, 0.995, and 0.995, respectively. The results indicated that there needs to be more awareness of the presence of one or more masked and emerging mycotoxins in maize silage in China.

Emerging mycotoxins and reproductive effects in animals: A short review

Emerging Fusarium mycotoxins beauvericin (BEA), enniatins (ENNs) and moniliformin (MON) are gaining increasing interest due to their wide presence especially in cereals and grain-based products. In vitro and in vivo studies indicate that Fusarium mycotoxins can be implicated in reproductive disorders in animals. Of these mycotoxins BEA may affect reproductive functions, impairing the development of oocytes in pigs and sheep. Studies show dramatic inhibitory effects of BEA and ENNA on bovine granulosa cell steroidogenesis. ENNs also inhibit boar sperm motility and cause detrimental effects on embryos in mice and pigs. Although little data are reported on reproductive effects of MON, in vitro studies show inhibitory effects of MON on Chinese hamster ovary cells. The present review aims to summarize the reproductive toxicological effects of emerging Fusarium mycotoxins BEA, ENNs and MON on embryo development, ovarian function, and testicular function of animals. In vitro and in vivo toxicological data are reported although additional studies are needed for proper risk assessment.

Perfluorooctane sulfonate affects mouse oocyte maturation in vitro by promoting oxidative stress and apoptosis induced bymitochondrial dysfunction

Perfluorooctane sulphonate (PFOS), as a surfactant, is widely applied in the agricultural production activities and has become a potential menace to human health. The mechanism of its effect on the maturation of mammalian oocytes is unclear. This study explored the toxic effect of PFOS on mouse oocyte maturation in vitro. The results revealed that PFOS under a concentration of 600 μM could significantly reduce the polar body extrusion rate (PBE) of mouse oocytes and cause symmetrical cell division. Further experiments showed that PFOS resulted in the abnormal cytoskeleton of the oocytes, causing the abnormal spindles and misplaced chromosomes, as well as the impaired dynamics of actin. Moreover, PFOS exposure inhibited the process of oocyte meiosis, which reflected in the slower spindle migration and continuous activation of spindle assembly checkpoint (SAC), then ultimately increased the probability of aneuploidy. Most importantly, PFOS exposure reduced the quality of oocytes, specifically by disrupting the function of mitochondria, inducing cell oxidative stress, and triggering early apoptosis. Furthermore, the level of methylation of histones is additionally influenced. In summary, our findings showed that PFOS exposure interfered with the maturation of mouse oocytes through affecting cytoskeletal dynamics, meiotic progression, oocyte quality, and histone modifications.

Susceptibility of Oocytes from Gilts and Sows to Beauvericin and Deoxynivalenol and Its Relationship with Oxidative Stress

Beauvericin (BEA) and deoxynivalenol are toxins produced by Fusarium species that can contaminate food and feed. The aim of this study was to assess the effects of these mycotoxins on the maturation of oocytes from gilts and sows. Furthermore, the antioxidant profiles in the oocytes' environment were assessed. Cumulus-oocyte-complexes (COCs) from gilts and sows were exposed to beauvericin (BEA) or deoxynivalenol (DON) and matured in vitro. As an extra control, these COCs were also exposed to reactive oxygen species (ROS). The maturation was mostly impaired when oocytes from gilts were exposed to 0.02 μmol/L DON. Oocytes from sows were able to mature even in the presence of 5 μmol/L BEA. However, the maturation rate of gilt oocytes was already impaired by 0.5 μmol/L BEA. It was observed that superoxide dismutase (SOD) and glutathione (GSH) levels in the follicular fluid (FF) of gilt oocytes was higher than that from sows. However, the expression of SOD1 and glutathione synthetase (GSS) was higher in the oocytes from sows than in those from gilts. Although DON and BEA impair cell development by diverse mechanisms, this redox imbalance may partially explain the vulnerability of gilt oocytes to these mycotoxins.

Melatonin protects against defects induced by Enniatin B1 during porcine early embryo development

Exogenous factors influence embryo development. Enniatin B1 (EB1), one emerging mycotoxin of Fusarium fungi, can cause damage to cells and mouse blastocysts. However, the toxicity of EB1 on porcine embryo development and whether melatonin can eliminate the detrimental effects of EB1 on embryos remain unclear. Here, this work demonstrated that EB1 significantly decreased the cleavage and blastocyst rates and blastocyst cell number of embryos in a dose and time dependent manner. Further study displayed that EB1 obviously destroyed nuclear remodeling dynamics. Importantly, EB1 triggered embryo apoptosis through downregulating the expression of Sod1,Gpx4, Cat and Bcl2l1 while upregulating the transcription of Bax and Caspase3. Moreover, EB1 significantly disrupted the transcription of Dnmt1, Dnmt3a, Tet1 and Tet3, further leading to incomplete DNA demethylation of CenRep, Oct4, Nanog and Sox2, thus, the expression of Eif1a, Oct4, Nanog and Sox2 remarkably decreased. Whereas EB1-exposed embryos were treated with melatonin, these disorders were obviously ameliorated, and the development ability of embryos was also rescued. In conclusion, EB1 exerted detrimental effects on porcine early embryos, while melatonin effectively rescued EB1-mediated defects in embryos. This work provides a novel insight into the improvement of embryo quality and the promotion of human and animal reproduction.

Fusarium Cyclodepsipeptide Mycotoxins: Chemistry, Biosynthesis, and Occurrence

Most of the fungi from the Fusarium genus are pathogenic to cereals, vegetables, and fruits and the products of their secondary metabolism mycotoxins may accumulate in foods and feeds. Non-ribosomal cyclodepsipeptides are one of the main mycotoxin groups and include beauvericins (BEAs), enniatins (ENNs), and beauvenniatins (BEAEs). When ingested, even small amounts of these metabolites significantly affect human and animal health. On the other hand, in view of their antimicrobial activities and cytotoxicity, they may be used as components in drug discovery and processing and are considered as suitable candidates for anti-cancer drugs. Therefore, it is crucial to expand the existing knowledge about cyclodepsipeptides and to search for new analogues of these compounds. The present manuscript aimed to highlight the extensive variability of cyclodepsipeptides by describing chemistry, biosynthesis, and occurrence of BEAs, ENNs, and BEAEs in foods and feeds. Moreover, the co-occurrence of Fusarium species was compared to the amounts of toxins in crops, vegetables, and fruits from different regions of the world.

The mycotoxin beauvericin impairs development, fertility and life span in the nematode Caenorhabditis elegans accompanied by increased germ cell apoptosis and lipofuscin accumulation

Beauvericin is an ubiquitous mycotoxin with relevant occurrence in food and feed. It causes a high toxicity in several cell lines, but its general mechanism of action is not fully understood and only limited in vivo studies have been performed. We used Caenorhabditis elegans as a model organism to investigate effects of beauvericin. The mycotoxin displays a moderate acute toxicity at 100 μM; at this concentration also reproductive toxicity occurred (reduction of total progeny to 32.1 %), developmental toxicity was detectable at 250 μM. However, even lower concentrations were capable to reduce stress resistance and life span of the nematode: A significant reduction was detected at 10 μM beauvericin (decrease in mean survival time of 4.3 % and reduction in life span of 12.9 %). An increase in lipofuscin fluorescence was demonstrated starting at 10 μM suggesting oxidative stress as a mechanism of beauvericin toxicity. Beauvericin (100 μM) increases the number of apoptotic germ cells comparable to the positive control UV-C (400 J/m²). Conclusion: Low concentrations of beauvericin are capable to cause adverse effects in C. elegans, which may be relevant for hazard identification of this compound.

Beauvericin alters the expression of genes coding for key proteins of the mitochondrial chain in ovine cumulus-oocyte complexes

Beauvericin (BEA) is a member of the enniatin family of mycotoxins which has received increasing interest because of frequent occurrence in food and feed. By its ionophoric properties, BEA is able to alter membrane ion permeability uncoupling oxidative phosphorylation. It was also shown to alter oocyte mitochondrial function. In this study, the effects of BEA at 0.5, 1, ,3 and 5 μmol/L on expression of genes coding for key proteins of the mitochondrial chain in ovine oocytes and cumulus cells were evaluated at different time points of in vitro maturation (IVM), germinal vesicle (GV; t = 0), metaphase I (MI; t = 7 h), and metaphase II (MII; t = 24 h). The expression of nuclear (TFAM, NDUFA12, UQCRH, COX4, ATP5O) and mitochondrial (ND1, COX1, COX2, ATP6, ATP8) genes coding for proteins of Complexes I, III, IV, and V was analyzed by qRT-PCR. After BEA exposure, perturbed expression of all genes was observed in cumulus cells and in oocytes at the MI stage (7 h IVM). Expression of ND1, UQCRH, COX4 and ATP5O was downregulated in cumulus cells and upregulated in oocytes starting from 0.5 μmol/L BEA. Expression of TFAM, NDUFA12, COX1, COX2, ATP6, and ATP8 was upregulated starting from 1 μmol/L in cumulus cells and from 3 μmol/L in oocytes. Cumulus cells and oocytes displayed different gene expression patterns upon BEA exposure. The downregulation in cumulus cells of four genes coding for proteins of mitochondrial complexes could represent a major toxic event induced by BEA on the cumulus-oocyte complex which may result in mitochondrial functional alteration.

Beauvericin: The beauty and the beast

Beauvericin (BEA) is a natural bioactive compound, with a dual nature. On the one hand, the peculiar characteristics of its molecule confer to BEA interesting properties, such as antibacterial, antiviral, antifungal, antiparasitic, insecticidal and anticarcinogenic activities. On the other hand, it is a natural contaminant of food and feed commodities, and an emerging mycotoxin, but lacks a toxicological risk assessment evaluation for long term exposure. This review aims to provide a global and comprehensive overview on BEA from its biological activities, to its in vivo and in vitro toxicological effects covering the multifaceted nature of this substance.

Toxicity of mycotoxins in vivo on vertebrate organisms: A review

Mycotoxins are considered to be a major risk factor affecting human and animal health as they are one of the most dangerous contaminants of food and feed. This review aims to compile the research developed up to date on the toxicological effects that mycotoxins can induce on human health, through the examination of a selected number of studies in vivo. AFB1 shows to be currently the most studied mycotoxin in vivo, followed by DON, ZEA and OTA. Scarce data was found for FBs, PAT, CIT, AOH and Fusarium emerging mycotoxins. The majority of them concerned the investigation of immunotoxicity, whereas the rest consisted in the study of genotoxicity, oxidative stress, hepatotoxicity, cytotoxicity, teratogenicity and neurotoxicity. In order to assess the risk, a wide range of different techniques have been employed across the reviewed studies: qPCR, ELISA, IHC, WB, LC-MS/MS, microscopy, enzymatic assays, microarray and RNA-Seq. In the last decade, the attention has been drawn to immunologic and transcriptomic aspects of mycotoxins' action, confirming their toxicity at molecular level. Even though, more in vivo studies are needed to further investigate their mechanism of action on human health.

Updates on the Effect of Mycotoxins on Male Reproductive Efficiency in Mammals

Mycotoxins are ubiquitous and unavoidable harmful fungal products with the ability to cause disease in both animals and humans, and are found in almost all types of foods, with a greater prevalence in hot humid environments. These mycotoxins vary greatly in structure and biochemical effects; therefore, by better understanding the toxicological and pathological aspects of mycotoxins, we can be better equipped to fight the diseases, as well as the biological and economic devastations, they induce. Multiple studies point to the association between a recent increase in male infertility and the increased occurrence of these mycotoxins in the environment. Furthermore, understanding how mycotoxins may induce an accumulation of epimutations during parental lifetimes can shed light on their implications with respect to fertility and reproductive efficiency. By acknowledging the diversity of mycotoxin molecular function and mode of action, this review aims to address the current limited knowledge on the effects of these chemicals on spermatogenesis and the various endocrine and epigenetics patterns associated with their disruptions.

Alternariol disturbs oocyte maturation and preimplantation development

Alternariol (AOH) is produced by fungi of the genus Alternaria and can be found in fruits, vegetables, and grains. Besides the oestrogenic activity demonstrated in vitro, this mycotoxin causes DNA damage and cell cycle arrest. Based on this, the effect of AOH was investigated on porcine female gametes during in vitro maturation and subsequent initial embryo development. A first experiment assessed a dose-response effect of AOH (5, 10, or 20 μmol/l) on cumulus expansion and in vitro oocyte nuclear maturation, in the presence or absence of follicular fluid (FF). A second experiment evaluated the effect of AOH (5, 10, or 20 μmol/l) exposure during porcine oocyte maturation, initial embryo development, or both periods, on preimplantation embryo development. Although FF protected oocytes from the deleterious effect of AOH, it did not avoid a decrease in cumulus cells expansion (5 μmol/l AOH regardless of the presence of FF). Moreover, exposure to AOH resulted in the degeneration of oocytes (10 μmol/l AOH in the absence of FF) and the occurrence of nuclear aberrations in mature oocytes (10 μmol/l AOH in the absence of FF and 20 μmol/l AOH in the presence of FF). Exposure to 5 μmol/l AOH during oocyte in vitro maturation was sufficient to impair initial embryo development.

The mycotoxin beauvericin induces oocyte mitochondrial dysfunction and affects embryo development in the juvenile sheep

Beauvericin (BEA) is a mycotoxin produced by Beauveria bassiana and Fusarium species recently reported as toxic on porcine oocyte maturation and embryo development. The aim of this study was to assess, in the juvenile sheep, whether its effects are due to alterations of oocyte and/or embryo bioenergetic/oxidative status. Cumulus-oocyte-complexes (COCs) were exposed to BEA during in vitro maturation (IVM), evaluated for cumulus cell (CC) apoptosis, oocyte maturation and bioenergetic/oxidative status or subjected to in vitro fertilization (IVF) and embryo culture (IVEC). Oocyte nuclear maturation and embryo development were assessed after Hoechst staining and CC apoptosis was analysed by terminal deoxynucleotidyl transferase-mediated dUTP nick-End labeling assay and chromatin morphology after Hoechst staining by epifluorescence microscopy. Oocyte and blastocyst bioenergetic/oxidative status were assessed by confocal microscopy after mitochondria and reactive oxygen species labelling with specific probes. BEA showed various toxic effects, that is, short-term effects on somatic and germinal compartment of the COC (CCs and the oocyte) and long-term carry-over effects on developing embryos. In detail, at 5 µM, it significantly reduced oocyte maturation and immature oocytes showed increased late-stage (Type C) CC apoptosis and DNA fragmentation while matured oocytes showed unaffected CC viability but abnormal mitochondrial distribution patterns. At lower tested concentrations (3-0.5 µM), BEA did not affect oocyte maturation, but matured oocytes showed reduced mitochondrial activity. At low concentrations, BEA impaired embryo developmental capacity and blastocyst quality after IVF and IVEC. In conclusion, in the juvenile sheep, COC exposure to BEA induces CC apoptosis and oocyte mitochondrial dysfunction with negative impact on embryo development.

Extracts of forage plants affect the developmental competence of ovine oocytes in vitro

Forage plants may contain secondary compounds that disrupt reproduction in ruminants so, as ‘duty of care’, proposed new forage species need to be tested for harmful effects on reproduction before industrial release. We evaluated the effects of Bituminaria bituminosa, Medicago sativa, Chicorium intybus, Trifolium subterraneum, Trifolium pratense, Biserrula pelecinus and Eremophila glabra, on the in vitro developmental competence of ovine oocytes. Crude methanolic extracts of each plant were added to the medium (final concentrations: 0, 50 or 100 μg dry extract per mL) used for in vitro maturation of cumulus-oocyte complexes derived from abattoir-sourced adult ewe ovaries. After in vitro fertilisation, we quantified cleavage rate, blastocyst rate, hatching rate, blastocyst efficiency, and total blastocyst cell number (TCN). Extract from B. pelecinus, at 50 μg/mL concentration, increased cleavage rate at (P &lt; 0.05), and at 100 μg/mL, increased blastocyst rate and efficiency (P &lt; 0.05). The other plant extracts did not affect these measures. TCN was affected by stage of development and treatment, but not by the interaction between stage and treatment. Within treatments, TCN was increased by C. intybus (at both 50 and 100 μg/mL) but decreased by M. sativa (at both 50 and 100 μg/mL; P &lt; 0.05). We conclude that methanolic extracts of forage plants, present during in vitro oocyte maturation, did not disrupt subsequent fertilisation and embryo development until the blastocyst stage. On the contrary, B. pelecinus appears to improve fertilisation and embryo development. Overall, these observations suggest that these plants will not disrupt in vivo oocyte maturation but further testing is still required, especially for the other stages of the reproductive process.

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.

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.

Transcriptomic study of the toxic mechanism triggered by beauvericin in Jurkat cells

Beauvericin (BEA), an ionophoric cyclic hexadepsipeptide mycotoxin, is able to increase oxidative stress by altering membrane ion permeability and uncoupling oxidative phosphorylation. A toxicogenomic study was performed to investigate gene expression changes triggered by BEA exposure (1.5, 3 and 5 μM; 24 h) in Jurkat cells through RNA-sequencing and differential gene expression analysis. Perturbed gene expression was observed in a concentration dependent manner, with 43 differentially expressed genes (DEGs) overlapped in the three studied concentrations. Gene ontology (GO) analysis showed several biological processes related to electron transport chain, oxidative phosphorylation, and cellular respiration significantly altered. Molecular functions linked to mitochondrial respiratory chain and oxidoreductase activity were over-represented (q-value < 0.01). Pathway analysis revealed oxidative phosphorylation and electron transport chain as the most significantly altered pathways in all studied doses (z-score > 1.96; adj p-value < 0.05). 77 genes involved in the respiratory chain were significantly down-regulated at least at one dose. Moreover, 21 genes related to apoptosis and programmed cell death, and 12 genes related to caspase activity were significantly altered, mainly affecting initiator caspases 8, 9 and 10. The results demonstrated BEA-induced mitochondrial damage affecting the respiratory chain, and pointing to apoptosis through the caspase cascade in human lymphoblastic T cells.

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.