Genotoxic potential associated with low levels of the Fusarium mycotoxins nivalenol and fusarenon X in a human intestinal cell line

Comparative Evaluation of Mutagenic, Genotoxic, Cytotoxic, and Antimicrobial Effects of Flavour and Fragrance Aldehydes, Ketones, Oximes, and Oxime Ethers

Despite the large number of odoriferous compounds available, new ones with interesting olfactory characteristics are desired due to their potentially high commercial value. Here, we report for the first time mutagenic, genotoxic, and cytotoxic effects, and antimicrobial properties of low-molecular fragrant oxime ethers, and we compare their properties with corresponding oximes and carbonyl compounds. 24 aldehydes, ketones, oximes, and oxime ethers were evaluated for mutagenic and cytotoxic effects in Ames (using Salmonella typhimurium strains TA 98 with genotype hisD3052, rfa, uvrB, pKM101, and TA100 with genotype hisG46, rfa, uvrB, pKM101, concentration range: 0.0781-40mg/mL) and MTS (using HEK293T cell line concentration of tested substances: 0.025mM) assays. Antimicrobial evaluation was carried out against Bacillus cereus (ATCC 10876), Staphylococcus aureus (ATCC 6538), Enterococcus hirae (ATCC 10541), Pseudomonas aeruginosa (ATCC 15442), Escherichia coli (ATCC 10536), Legionella pneumophila (ATCC 33152); Candida albicans (ATCC 10231) and Aspergillus brasiliensis (ATCC 16404) with concentration range of tested substances 9.375 - 2.400mg/mL. Furthermore, 5 representatives of carbonyl compounds, oximes, and an oxime ether (stemone, buccoxime, citral, citral oxime, and propiophenone oxime O-ethyl ether) were evaluated for genotoxic properties in SOS-Chromotest (concentration range: 7.8·10^-5 - 5·10^-3mg/mL). All of the tested compounds did not exhibit mutagenic, genotoxic, or cytotoxic effects. Oximes and oxime ethers showed relevant antimicrobial activity against pathogenic species (P. aeruginosa, S. aureus, E.coli, L. pneumophila, A. brasiliensis, C. albicans) in the MIC range 0.075 - 2.400mg/mL compared to the common preservative methylparaben with the MIC range 0.400-3.600mg/mL. Our study shows that oxime ethers have the potential to be used as fragrant agents in functional products.

Mycotoxins and Essential Oils-From a Meat Industry Hazard to a Possible Solution: A Brief Review

The preservation of food supplies has been humankind's priority since ancient times, and it is arguably more relevant today than ever before. Food sustainability and safety have been heavily prioritized by consumers, producers, and government entities alike. In this regard, filamentous fungi have always been a health hazard due to their contamination of the food substrate with mycotoxins. Additionally, mycotoxins are proven resilient to technological processing. This study aims to identify the main mycotoxins that may occur in the meat and meat products "Farm to Fork" chain, along with their effect on the consumers' health, and also to identify effective methods of prevention through the use of essential oils (EO). At the same time, the antifungal and antimycotoxigenic potential of essential oils was considered in order to provide an overview of the subject. Targeting the main ways of meat products' contamination, the use of essential oils with proven in vitro or in situ efficacy against certain fungal species can be an effective alternative if all the associated challenges are addressed (e.g., application methods, suitability for certain products, toxicity).

Mycotoxins’ Toxicological Mechanisms Involving Humans, Livestock and Their Associated Health Concerns: A Review

Mycotoxins are well established toxic metabolic entities produced when fungi invade agricultural/farm produce, and this happens especially when the conditions are favourable. Exposure to mycotoxins can directly take place via the consumption of infected foods and feeds; humans can also be indirectly exposed from consuming animals fed with infected feeds. Among the hundreds of mycotoxins known to humans, around a handful have drawn the most concern because of their occurrence in food and severe effects on human health. The increasing public health importance of mycotoxins across human and livestock environments mandates the continued review of the relevant literature, especially with regard to understanding their toxicological mechanisms. In particular, our analysis of recently conducted reviews showed that the toxicological mechanisms of mycotoxins deserve additional attention to help provide enhanced understanding regarding this subject matter. For this reason, this current work reviewed the mycotoxins’ toxicological mechanisms involving humans, livestock, and their associated health concerns. In particular, we have deepened our understanding about how the mycotoxins’ toxicological mechanisms impact on the human cellular genome. Along with the significance of mycotoxin toxicities and their toxicological mechanisms, there are associated health concerns arising from exposures to these toxins, including DNA damage, kidney damage, DNA/RNA mutations, growth impairment in children, gene modifications, and immune impairment. More needs to be done to enhance the understanding regards the mechanisms underscoring the environmental implications of mycotoxins, which can be actualized via risk assessment studies into the conditions/factors facilitating mycotoxins’ toxicities.

Fusarium Mycotoxins, Their Metabolites (Free, Emerging, and Masked), Food Safety Concerns, and Health Impacts

The genus Fusarium produces a number of mycotoxins of diverse chemical structures. Fusariotoxins are secondary metabolites produced by toxigenic fungi of the genus Fusarium. The important and commonly encountered fusariotoxins are trichothecenes, fumonisins, and zearalenone. Fusarium mycotoxins pose varying toxicities to humans and/or animals after consumption of contaminated grain. They can cause acute or chronic illness and, in some cases, death. For instance, a range of Fusarium mycotoxins can alter different intestinal defense mechanisms, such as the epithelial integrity, cell proliferation, mucus layer, immunoglobulins, and cytokine production. Of recent concern is the occurrence of emerging and masked Fusarium mycotoxins in agricultural commodities, which may contribute to toxic health effects, although the metabolic fate of masked mycotoxins still remains a matter of scientific discussion. These mycotoxins have attracted attention worldwide because of their impact on human and animal health, animal productivity, and the associated economic losses. In this paper, we review Fusarium mycotoxins and their metabolites with the aim of summarizing the baseline information on the types, occurrence, and health impacts of these mycotoxins in order to encourage much-needed research on integrated management of this unavoidable food contaminant as concerns for food safety continues to grow worldwide.

Fungal Toxins and Host Immune Responses

Fungi are ubiquitous organisms that thrive in diverse natural environments including soils, plants, animals, and the human body. In response to warmth, humidity, and moisture, certain fungi which grow on crops and harvested foodstuffs can produce mycotoxins; secondary metabolites which when ingested have a deleterious impact on health. Ongoing research indicates that some mycotoxins and, more recently, peptide toxins are also produced during active fungal infection in humans and experimental models. A combination of innate and adaptive immune recognition allows the host to eliminate invading pathogens from the body. However, imbalances in immune homeostasis often facilitate microbial infection. Despite the wide-ranging effects of fungal toxins on health, our understanding of toxin-mediated modulation of immune responses is incomplete. This review will explore the current understanding of fungal toxins and how they contribute to the modulation of host immunity.

Nrf2: a main responsive element in cells to mycotoxin-induced toxicity

Nuclear factor erythroid 2-like 2 (Nrf2) is a transcription factor participating in response to cellular oxidative stress to maintain the redox balance. Generation of reactive oxygen species (ROS) and, in consequence, oxidative stress, are physiological as well as pathological processes which take place in almost all types of cells. Nrf2, in response to oxidative stress, activates expression and production of antioxidant enzymes to remove free radicals. However, the role of Nrf2 seems to be more sophisticated and its increased expression observed in cancer cells allows to draw a conclusion that its role is tissue—and condition—dependent. Interestingly, Nrf2 might also play a crucial role in response to environmental factors like mycotoxins. Thus, the aim of the study is to review the role of Nrf2 in cells exposed to most common mycotoxins to check if the Nrf2 signaling pathway serves as the main response element to mycotoxin-induced oxidative stress in human and animal cells and if it can be a target of detoxifying agents.

Genotoxic effects of mycotoxins

Fungi produce mycotoxins in the presence of appropriate temperature, humidity, sufficient nutrients and if the density of the mushroom mass is favorable. Although all mycotoxins are of fungal origin, all toxic compounds produced by fungi are not called mycotoxins. The interest in mycotoxins first started in the 1960s, and today the interest in mycotoxin-induced diseases has increased. To date, 400 mycotoxins have been identified and the most important species producing mycotoxins belongs to Aspergillus, Penicillium, Alternaria and Fusarium genera. Mycotoxins are classified as hepatotoxins, nephrotoxins, neurotoxins, immunotoxins etc. In this review genotoxic and also other health effects of some major mycotoxin groups like Aflatoxins, Ochratoxins, Patulin, Fumonisins, Zearalenone, Trichothecenes and Ergot alkaloids were deeply analyzed.

Fusarium Toxins in Chinese Wheat since the 1980s

Wheat Fusarium head blight (FHB), caused by Fusarium species, is a widespread and destructive fungal disease. In addition to the substantial yield and revenue losses, diseased grains are often contaminated with Fusarium mycotoxins, making them unsuitable for human consumption or use as animal feed. As a vital food and feed ingredient in China, the quality and safety of wheat and its products have gained growing attention from consumers, producers, scientists, and policymakers. This review supplies detailed data about the occurrence of Fusarium toxins and related intoxications from the 1980s to the present. Despite the serious situation of toxin contamination in wheat, the concentration of toxins in flour is usually lower than that in raw materials, and food-poisoning incidents have been considerably reduced. Much work has been conducted on every phase of toxin production and wheat circulation by scientific researchers. Regulations for maximum contamination limits have been established in recent years and play a substantial role in ensuring the stability of the national economy and people's livelihoods.

Primary and Immortalized Human Respiratory Cells Display Different Patterns of Cytotoxicity and Cytokine Release upon Exposure to Deoxynivalenol, Nivalenol and Fusarenon-X

The type B trichothecene mycotoxins deoxynivalenol (DON), nivalenol (NIV) and fusarenon-X (FX) are structurally related secondary metabolites frequently produced by Fusarium on wheat. Consequently, DON, NIV and FX contaminate wheat dusts, exposing grain workers to toxins by inhalation. Those trichothecenes at low, relevant, exposition concentrations have differential effects on intestinal cells, but whether such differences exist with respiratory cells is mostly unknown, while it is required to assess the combined risk of exposure to mycotoxins. The goal of the present study was to compare the effects of DON, NIV and FX alone or in combination on the viability and IL-6 and IL-8-inducing capacity of human epithelial cells representative of the respiratory tract: primary human airway epithelial cells of nasal (hAECN) and bronchial (hAECB) origin, and immortalized human bronchial (16HBE14o-) and alveolar (A549) epithelial cell lines. We report that A549 cells are particularly resistant to the cytotoxic effects of mycotoxins. FX is more toxic than DON and NIV for all epithelial cell types. Nasal and bronchial primary cells are more sensitive than bronchial and alveolar cell lines to combined mycotoxin mixtures at low concentrations, although they are less sensitive to mycotoxins alone. Interactions between mycotoxins at low concentrations are rarely additive and are observed only for DON/NIV and NIV/FX on hAECB cells and DON/NIV/FX on A549 cells. Most interactions at low mycotoxin concentrations are synergistic, antagonistic interactions being observed only for DON/FX on hAECB, DON/NIV on 16HBE14o- and NIV/FX on A549 cells. DON, NIV and FX induce, albeit at different levels, IL-6 and IL-8 release by all cell types. However, NIV and FX at concentrations of low cytotoxicity induce IL-6 release by hAECB and A549 cells, and IL-8 release by hAECN cells. Overall, these data suggest that combined exposure to mycotoxins at low concentrations have a stronger effect on primary nasal epithelial cells than on bronchial epithelial cells and activate different inflammatory pathways. This information is particularly relevant for future studies about the hazard of occupational exposure to mycotoxins by inhalation and its impact on the respiratory tract.

Health Risks Associated with Exposure to Filamentous Fungi

Filamentous fungi occur widely in the environment, contaminating soil, air, food and other substrates. Due to their wide distribution, they have medical and economic implications. Regardless of their use as a source of antibiotics, vitamins and raw materials for various industrially important chemicals, most fungi and filamentous fungi produce metabolites associated with a range of health risks, both in humans and in animals. The association of filamentous fungi and their metabolites to different negative health conditions in humans and animals, has contributed to the importance of investigating different health risks induced by this family of heterotrophs. This review aims to discuss health risks associated with commonly occurring filamentous fungal species which belong to genera Aspergillus, Penicillium and Fusarium, as well as evaluating their pathogenicity and mycotoxic properties.

Effects of different mycotoxins on humans, cell genome and their involvement in cancer (Review)

The chemical nature of most of the mycotoxins makes them highly liposoluble compounds that can be absorbed from the site of exposure such as from the gastrointestinal and respiratory tract to the blood stream where it can be dissimilated throughout the body and reach different organs such as the liver and kidneys. Mycotoxins have a strong tendency and ability to penetrate the human and animal cells and reach the cellular genome where it causes a major mutagenic change in the nucleotide sequence which leads to strong and permanent defects in the genome. This defect will eventually be transcribed, translated and lead to the development of cancer. In this review, the chemical and physical nature of mycotoxins, the action of mycotoxins on the cellular genome and its effect on humans, mycotoxins and their carcinogenicity and mycotoxins research gaps are discussed, and new research areas are suggested. The research review posed various questions. What are the different mycotoxins that can cause cancer, what is the role of mycotoxins in causing cancer and what types of cancers can be caused by mycotoxins? These questions have been selected due to the significant increase in the mycotoxin contamination and the cancer incidence rate in the contemporary world. By revealing and understanding the role of mycotoxins in developing cancer, measures to reduce the risks and incidents of cancer could be taken.

An overview of the toxicology and toxicokinetics of fusarenon-X, a type B trichothecene mycotoxin

Fusarenon-X (FX) is a type B trichothecene mycotoxin that is frequently observed along with deoxynivalenol (DON) and nivalenol (NIV) in agricultural commodities. This review aims to give an overview of the literature concerning the toxicology and toxicokinetics of FX. FX is primarily found in cereals grown in temperate regions, but it can also be found worldwide because of the global transport of products. The major toxicity of FX occurs through inhibition of protein synthesis, followed by the disruption of DNA synthesis. Moreover, FX has also been shown to induce apoptosis in in vitro and in vivo studies. The targets of FX are organs containing actively proliferating cells, such as the thymus, spleen, skin, small intestine, testes and bone marrow. FX causes immunosuppression, intestinal malabsorption, developmental toxicity and genotoxicity. In addition, sufficient evidence of carcinogenicity in experimental animals is currently lacking, and the International Agency for Research on Cancer (IARC) classifies it as a group 3 carcinogen.

Evaluation of the cytotoxic properties, gene expression profiles and secondary signalling responses of cultured cells exposed to fumonisin B1, deoxynivalenol and zearalenone mycotoxins

Mycotoxins are toxic secondary metabolites produced by a range of fungi and are common contaminants of agricultural crops. These toxins are chemically diverse and structurally stable, enabling them to enter the food chain which can lead to numerous adverse health effects in animals and humans. Although mycotoxin exposure is associated with the development of several cancers, it has proved challenging to show a direct connection between exposure and oncogenic change. This study investigates the in vitro cytotoxicity, molecular mechanisms and secondary signalling responses associated with the exposure to three major mycotoxins, fumonisin B1 (FB1), deoxynivalenol (Don) and zearalenone (Zea). The cytotoxicity of FB1, Don and Zea were investigated in cultured HepG2 and Caco-2 cells using cell viability assays as well as flow cytometry. FB1 proved to be less cytotoxic than its counterparts, while Don and Zea demonstrated high cytotoxicity through an apoptotic mechanism. Expression profiles of 84 genes involved in mediating communication between tumour cells and the cellular mediators of inflammation as well as the innate immune system were also studied. The expression profiles associated with the different mycotoxins were further explored for functional networks, biological functions, canonical pathways, toxicological association as well as to predict network associations between the differentially expressed genes. RT-qPCR revealed the significant differential expression of 46 genes, including the expression of several genes strongly associated with cancer and aberrant inflammatory signalling, after mycotoxin exposure. Aberrant inflammatory signalling seems to be a credible contributing factor that initiates the malignant change observed in cells exposed to mycotoxins.

Fungal isolates and metabolites in locally processed rice from five agro-ecological zones of Nigeria

This study reports the distribution of fungal isolates and fungal metabolites that naturally contaminate locally processed rice from five agro-ecological zones of Nigeria. The fungal species were isolated by the dilution plate technique and identified by appropriate diagnostics, while metabolites were determined by a liquid chromatographic tandem mass spectrometric method. Aspergillus and Penicillium species were the predominant isolates found in the rice samples while Fusarium spp. were not isolated. The mean fungal count differed significantly (p < 0.05) across the zones and ranged from 9.98 × 10² cfu g^-1 in the Southern Guinea Savannah to 96.97 × 10² cfu g^-1 in the Derived Savannah. For 16 fungal metabolites, selected from 63 positively identified fungal metabolites based on their concentration and spread across the zones, an occurrence map was constructed. The Northern Guinea Savannah recorded the highest contamination of fungal metabolites while the Sudan Savannah zone recorded the least.

Fusarenon-X-induced apoptosis in the liver, kidney, and spleen of mice

Fusarenon-X is a non-macrocyclic type B trichothecene mycotoxin. It occurs naturally in agricultural commodities, such as wheat and barley. We investigated fusarenon-X-induced apoptosis in the liver, kidney, and spleen of male and female mice after a single exposure. Thus, mice were orally administered fusarenon-X (4 mg/kg body weight) and were assessed at 0, 3, 9, 18, 24, and 48 hours after treatment. Apoptosis in the liver, kidney, and spleen was determined using hematoxylin and eosin staining, the terminal deoxynucleotidyl transferase dUTP nick end labeling method, immunohistochemistry for proliferating cell nuclear antigen, and electron microscopy. Fusarenon-X-induced apoptosis at 9 hours after treatment, particularly hepatocytes around the central lobular zone of the liver, in proximal tubular cells of the kidney, and in hematopoietic cells in the red pulp area of the spleen in both male and female mice. The results of this study should be very useful with regard to the toxicity of fusarenon-X in both humans and domestic animals, which has been attributed to the intake of food contaminated with mycotoxins, especially fusarenon-X.

Apoptosis and gene expression in the developing mouse brain of fusarenon-X-treated pregnant mice

Fusarenon-X (FX), a type B trichothecene mycotoxin, is mainly produced by Fusarium crookwellense, which occurs naturally in agricultural commodities, such as wheat and barley. FX has been shown to exert a variety of toxic effects on multiple targets in vitro. However, the embryonic toxicity of FX in vivo remains unclear. In the present study, we investigated FX-induced apoptosis and the relationship between the genetic regulatory mechanisms and FX-induced apoptosis in the developing mouse brain of FX-treated pregnant mice. Pregnant mice were orally administered FX (3.5 mg/kg b.w.) and were assessed at 0, 12, 24 and 48 h after treatment (HAT). Apoptosis in the fetal brain was determined using hematoxylin and eosin staining, the TUNEL method, immunohistochemistry for PCNA and electron microscopy. Gene expressions were evaluated using microarray and real time-reverse transcription polymerase chain reaction (qRT-PCR). Histopathological changes showed that the number of apoptotic cells in the telencephalon of the mouse fetus peaked at 12 HAT and decreased at 24 and 48 HAT. FX induced the up-regulation of Bax, Trp53 and Casp9 and down-regulated Bcl2 but the expression levels of Fas and Casp8 mRNA remained unchanged. These data suggested that FX induces apoptosis in the developing mouse brain in FX-treated dams. Moreover, the genetic regulatory mechanisms of FX-induced apoptosis are regulated by Bax, Bcl2, Trp53 and Casp9 or can be defined via an intrinsic apoptotic pathway.

Effect of deoxynivalenol and other Type B trichothecenes on the intestine: a review

The natural food contaminants, mycotoxins, are regarded as an important risk factor for human and animal health, as up to 25% of the world's crop production may be contaminated. The Fusarium genus produces large quantities of fusariotoxins, among which the trichothecenes are considered as a ubiquitous problem worldwide. The gastrointestinal tract is the first physiological barrier against food contaminants, as well as the first target for these toxicants. An increasing number of studies suggest that intestinal epithelial cells are targets for deoxynivalenol (DON) and other Type B trichothecenes (TCTB). In humans, various adverse digestive symptoms are observed on acute exposure, and in animals, these toxins induce pathological lesions, including necrosis of the intestinal epithelium. They affect the integrity of the intestinal epithelium through alterations in cell morphology and differentiation and in the barrier function. Moreover, DON and TCTB modulate the activity of intestinal epithelium in its role in immune responsiveness. TCTB affect cytokine production by intestinal or immune cells and are supposed to interfere with the cross-talk between epithelial cells and other intestinal immune cells. This review summarizes our current knowledge of the effects of DON and other TCTB on the intestine.

The Kidneys of Infant Mice are not Sensitive to the Food Mycotoxin Contaminant Nivalenol

Nivalenol (NIV) is a trichothecene mycotoxin produced by Fusarium fungi that frequently contaminates agricultural commodities. Dietary administration of NIV to adult mice affects the renal glomeruli, but data about NIV toxicity in human infants are limited. To evaluate the effects of NIV on infant kidneys, 3-week-old male ICR-derived glomerulonephritis (ICGN) and ICR mice were administered 0, 4, 8 or 16 ppm NIV in diet for 4 weeks, and their renal status was compared with age-matched or adult ICR mice. In ICGN mice, the number of glomeruli showing mesangial expansion and α-smooth muscle actin (SMA)-positive mesangial cells was higher with 16 ppm NIV compared with controls. No other significant differences were observed in ICGN mice. In infant ICR mice, the IgA serum concentrations were significantly elevated without glomerular morphological changes in the 16 ppm NIV group. There was no difference in NIV sensitivity in the kidneys of infant ICGN and ICR mice. These data suggest that the kidneys in infant mice are not sensitive to nivalenol under the present conditions.

Simultaneous determination of deoxynivalenol, and 15- and 3-acetyldeoxynivalenol in cereals by HPLC-UV detection

Fusarium head blight is an important cereal crop disease, which not only causes yield losses but also mycotoxin contamination in wheat and other cereal grains. Developing an accurate, rapid and efficient assay is critical to minimise the risk of Fusarium mycotoxins for human and animal health. In this study, HPLC with UV detection was used to separate and quantify deoxynivalenol, 15-acetyldeoxynivalenol and 3-acetyldeoxynivalenol in cereals. Samples were extracted with water, and the extracting solution was precipitated by adding an equal volume of ethanol followed by solid-phase extraction. The analytes were separated on a reversed-phase C18 column by a mobile phase composed of acetonitrile and 1 mM H3PO4 with gradient elution. 15- and 3-acetyldeoxynivalenol showed effective baseline separation. All analytes were well-resolved from matrix co-extractives and detected at 224 nm. The results showed good linearity of calibration curves (R2 ranged from 0.997 to 0.999) and excellent precision for inter- and intra-day determinations. Average recovery rates for the tested matrices ranged from 71 to 92%. The limits of detection and quantification ranged from 16 to 25 ng/g and 48 to 60 ng/g, respectively. The results indicate that the feasibility and practicality of the presented LC-UV method are excellent and that the method is suitable for routine analysis of DON and its acetyl derivatives in cereal grains.

Apoptotic effects of satratoxin H is mediated through DNA double-stranded break in PC12 cells

Satratoxin H is an important air- and food-borne mycotoxin, which has been implicated in human health damage. Satratoxin H is known to induce apoptosis as well as genotoxicity in PC12 cells. In the present study, we further investigated the mechanism of apoptotic effects of satratoxin H with focus on caspase-3 and poly-ADP-ribose polymerase (PARP) pathway. We also examined whether it induces DNA damage in PC12 cells. In the cells treated with satratoxin H, caspase-3 was cleaved in a time-dependent manner. Furthermore, satratoxin H induced cleavage of PARP, one of the downstream molecules of caspase-3. The cleavage was inhibited by SB203580, a p38 MAPK inhibitor, or SP600125, a JNK inhibitor. Satratoxin H, however, had no effect on expression levels of Bax and Bcl-2. Furthermore, the micronucleus assay revealed that satratoxin H induced chromosome break. Also, satratoxin H increased the level of phosphorylation of histone H2A, indicating that it caused DNA double-stranded breaks in PC12 cells. Meanwhile, no genotoxicity was detected with any of treatments carried out in the alkaline comet assay. These results imply that satratoxin H induces genotoxicity by DNA double-stranded break. Our results suggest a considerable potential for the genotoxic risk associated with the presence of satratoxin H.

Nivalenol and deoxynivalenol affect rat intestinal epithelial cells: a concentration related study

The integrity of the gastrointestinal tract represents a crucial first level defence against ingested toxins. Among them, Nivalenol is a trichotecenes mycotoxin frequently found on cereals and processed grains; when it contaminates human food and animal feed it is often associated with another widespread contaminant, Deoxynivalenol. Following their ingestion, intestinal epithelial cells are exposed to concentrations of these trichothecenes high enough to cause mycotoxicosis. In this study we have investigated the effects of Nivalenol and Deoxynivalenol on intestinal cells in an in vitro model system utilizing the non-tumorigenic rat intestinal epithelial cell line IEC-6. Both Nivalenol and Deoxynivalenol (5-80 µM) significantly affected IEC-6 viability through a pro-apoptotic process which mainly involved the following steps: (i) Bax induction; (ii) Bcl-2 inhibition, and (iii) caspase-3 activation. Moreover, treatment with Nivalenol produced a significant cell cycle arrest of IEC-6 cells, primarily at the G(0)/G(1) interphase and in the S phase, with a concomitant reduction in the fraction of cells in G(2). Interestingly, when administered at lower concentrations (0.1-2.5 µM), both Nivalenol and Deoxynivalenol affected epithelial cell migration (restitution), representing the initial step in gastrointestinal wound healing in the gut. This reduced motility was associated with significant remodelling of the actin cytoskeleton, and changes in expression of connexin-43 and focal adhesion kinase. The concentration range of Nivalenol or Deoxynivalenol we have tested is comparable with the mean estimated daily intake of consumers eating contaminated food. Thus, our results further highlight the risks associated with intake of even low levels of these toxins.

Deoxynivalenol and its toxicity

Deoxynivalenol (DON) is one of several mycotoxins produced by certain Fusarium species that frequently infect corn, wheat, oats, barley, rice, and other grains in the field or during storage. The exposure risk to human is directly through foods of plant origin (cereal grains) or indirectly through foods of animal origin (kidney, liver, milk, eggs). It has been detected in buckwheat, popcorn, sorgum, triticale, and other food products including flour, bread, breakfast cereals, noodles, infant foods, pancakes, malt and beer. DON affects animal and human health causing acute temporary nausea, vomiting, diarrhea, abdominal pain, headache, dizziness, and fever. This review briefly summarizes toxicities of this mycotoxin as well as effects on reproduction and their antagonistic and synergic actions.

Mutagens manufactured in fungal culture may affect DNA/RNA of producing fungi

Self-produced mutagens in culture by fungi may affect DNA analysis of the same fungi. This has not been considered previously. Many fungi produce numerous mutagenic secondary metabolites (SM) in culture. There is a paradox of growing fungi in media to produce representative DNA which also support mutagenic SM. This is a crucial issue in developing diagnostic and phylogenetic methods, especially for closely-related fungi. For example, idh gene analysis of the patulin metabolic pathway in fungi can be interpreted as producing some false negative and positive results in terms of possession, or nonpossession, of the gene from mutated strains. The most obvious mycotoxins and fungi to consider in this regard are aflatoxins and Aspergillus, as aflatoxins are the most mutagenic natural compounds. Many other fungi and SM are relevant. Conditions to grow fungi have not been selected to inhibit SM production although relevant data exist. In fact, fungi repair damaged nucleic acid (NA) and are capable of removing toxins by employing transporter proteins. These and NA repair mechanisms could be inhibited by secondary metabolites. Mutagenic effects may involve inhibition of DNA stabilizing enzymes. There may be an equivalent situation for bacteria. Researchers need to devise methods to reduce SM for valid protocols. More work on how mutagens affect the NA of producing fungus in vitro is required. The current review assesses the potential seriousness of the situation with selected papers.

Toxicology of mycotoxins

Humans are exposed to mycotoxins via ingestion, contact and inhalation. This must have occurred throughout human history and led to severe outbreaks. Potential diseases range from akakabio-byo to stachybotryotoxicosis and cancer. The known molecular bases of toxicology run the gamut of 23 compounds, from aflatoxins (AFs) to zearalenone, ochratoxin A and deoxynivalenol. Ergotism is one of the oldest recognized mycotoxicosis, although mycotoxin science only commenced in the 1960s with the discovery of AFs in turkey feed. AFs are carcinogenic. Some others are suspected carcinogens. The effects of mycotoxins are acute or chronic in nature. Mycotoxins are well known in the scientific community, although they have a low profile in the general population. An incongruous situation occurs in United States where mycotoxins from "moldy homes" are considered to be a significant problem, although there is a general debate about seriousness. This contrasts with the thousands of deaths from mycotoxins that occur, even now, in the technologically less developed countries (e.g., Indonesia, China, and Africa). Mycotoxins are more toxic than pesticides. Studies are moving from whole animal work to investigating the biochemical mechanisms in isolated cells, and the mechanisms of toxicity at the molecular level are being elucidated. The stereochemical nature of AFs has been shown to be important. In addition, the effect of multiple mycotoxins is being increasingly investigated, which will more accurately represent the situation in nature. It is anticipated that more fungal metabolites will be recognized as dangerous toxins and permitted statutory levels will decrease in the future.

Genetic Fusarium chemotyping as a useful tool for predicting nivalenol contamination in winter wheat

Fusarium graminearum [teleomorph Gibberella zeae] and Fusarium culmorum together with Fusarium poae are the main species known to produce nivalenol (NIV). The NIV content in wheat (Triticum aestivum L.) harvested in Luxembourg was investigated in 2007 and 2008 at 17 different locations. Species determination and genetic chemotyping of F. graminearum and F. culmorum were used to understand the spatial distribution of NIV producers in wheat from Luxembourg. Three hundred thirteen F. graminearum, 175 F. culmorum and 117 F. poae strains respectively were isolated. Chemotypes of the first two species were determined by PCR and confirmed on a sub-sample of single isolates by LC-MS/MS analysis. The 15-acetylated DON chemotype of F. graminearum was dominant in both years representing 94.2% of the population while the NIV chemotype represented 5.8%. The F. culmorum chemotypes were rather evenly distributed, with 3-acetylated DON and NIV profiles present with similar abundances (53.2% and 46.8%, respectively). NIV presence in wheat flour obtained from the 17 sites was correlated with the number of F. culmorum (NIV chemotype) isolated from 100 seeds, suggesting its primary role in NIV production on grains. The predictive power for identifying NIV contamination in grains based on NIV chemotype presence was confirmed by coupling the isolation procedure with a cut-off value, resulting in the successful identification (100%, p=0.008) of NIV contamination in grains collected from 9 additional experimental sites. In conclusion, the results highlight the importance of chemotyping for improved prediction of toxin contamination in wheat.

Fumonisins, trichothecenes and zearalenone in cereals

Fumonisins are phytotoxic mycotoxins which are synthesized by various species of the fungal genus Fusarium such as Fusarium verticillioides (Sacc.) Nirenberg (ex F.moniliforme Sheldon) and Fusarium proliferatum. The trichothecene (TC) mycotoxins are secondary metabolites produce by species that belong to several fungal genera, especially Fusarium, Stachybotrys, Trichothecium, Trichoderma, Memnoniella and Myrothecium. Fusarium mycotoxins are widely dispersed in cereals and their products. Zearalenone (ZEA) is an estrogenic compound produced by Fusarium spp. such as F. graminearum and F. culmorum. Fumonisins, the TCs and ZEA are hazardous for human and animal health. Contamination with TCs causes a number of illnesses in human and animal such as decrease in food consumption (anorexia), depression or inhibition on immune system function and haematoxicity. The purpose of this paper is to give a review of the papers published on the field of fumonisin, TC and ZEA mycotoxins in cereals consumed in the world.

Immunotoxicity of nivalenol after subchronic dietary exposure to rats

Immunobiological effects of nivalenol (NIV), a trichothecene mycotoxin produced by Fusarium nivale, were examined in male F344 rats after 90-day dietary exposure at doses of 0, 0.4, 1.5, and 6.9 mg/kg body weight/day (0, 6.25, 25 and 100 ppm, respectively) in a subchronic toxicity study. With regards to the serum immunoglobulin levels, a slight increase of IgM was observed only at 6.9 mg/kg (26% increase), while levels of IgG and IgA did not fluctuate at any dose. Flow cytometric analysis of splenic cells revealed a dose-dependent decrease of T lymphocyte/B lymphocyte (CD3(+)/B220(+)) ratio from 1.5mg/kg and an elevated CD4(+)helper/CD8(+)cytotoxic T lymphocyte ratio at 6.9 mg/kg. Furthermore, increases of natural killer (NK) activity of splenic lymphocytes against YAC-1 target cells were observed at all doses, while the magnitude of changes was similar between 1.5 and 6.9 mg/kg. At 6.9 mg/kg, the reduction of the ratio of NKR-P1A(+) splenic cells, which is an indicator of NK cells in the spleen, was apparent. As with other previous studies of NIV, decreased body weight was observed from 1.5 mg/kg during the experiment in the present study. In summary, NIV affected immune function in rats after 90-day dietary exposure, the effects being apparent from 0.4 mg/kg judging from the increase of NK activity, although nutritional suppression might have influenced the immunological changes appeared from 1.5mg/kg.