Cytotoxicity of fungal metabolites to lepidopteran (Spodoptera frugiperda) cell line (SF-9)

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.

Rapid analysis of insecticidal metabolites from the entomopathogenic fungus Beauveria bassiana 331R using UPLC-Q-Orbitrap MS

Beauveria bassiana, a representative entomopathogenic fungus, is increasingly being utilized as an eco-friendly pest management alternative to chemical insecticides. This fungus produces a range of insecticidal secondary metabolites that act as antimicrobial and immunosuppressive agents. However, detailed qualitative and quantitative analysis related to these compounds remains scarce, we developed a method for the rapid analysis of these metabolites. Eight secondary metabolites (bassianin, bassianolide, beauvericin, beauveriolide I, enniatin A, A1, and B, and tenellin) were efficiently extracted when B. bassiana-infected Tenebrio molitor larvae were ground in 70% EtOH extraction solvent and subsequently subjected to ultrasonic treatment for 30 min. The eight metabolites were rapidly and simultaneously analyzed using ultra-performance liquid chromatography-quadrupole-Orbitrap mass spectrometry (UPLC-Q-Orbitrap MS). Bassianolide (20.6-51.1 µg/g) and beauvericin (63.6-109.8 µg/g) were identified as the main metabolites in B. basssiana-infected larvae, indicating that they are likely major toxins of B. bassiana. Validation of the method exhibited recovery rates in the range of 80-115% and precision in the range of 0.1-8.0%, indicating no significant interference from compounds in the matrix. We developed a method to rapidly analyze eight insecticidal metabolites using UPLC-Q-Orbitrap MS. This can be extensively utilized for detecting and producing insecticidal fungal secondary metabolites.

Pathogenicity analysis and comparative genomics reveal the different infection strategies between the generalist Metarhizium anisopliae and the specialist Metarhizium acridum

BACKGROUND

The fungal genera Metarhizium contain many important multiple species that are used as biocontrol agents and as model organisms for exploring insect-fungal interactions. Metarhizium spp. exhibit different traits of pathogenicity, suggesting that the pathogenesis can be quite distinctive. However, the underlying differences in their pathogenesis remain poorly understood.

RESULTS

Pathogenicity analysis showed that Metarhizium anisopliae (strain CQMa421) displayed higher virulence against oriental migratory locusts, Locusta migratoria manilensis (Meyen), than the acridid-specific specie Metarhizium acridum (strain CQMa102). Relative to M. acridum, M. anisopliae possessed a higher conidial hydrophobicity, increased ability to penetrate the host, accelerated growth under hypoxia and enhanced ability for the utilization of different carbon sources. Different distributions of carbohydrate epitopes at cell wall surface of M. anisopliae might also contribute to successful evasion of host immune defenses. Comparative genomics showed that M. anisopliae has 98 more virulence-related secreted proteins (133) than M. acridum (35), which can be functionally classified as hydrolases, virulence effectors, cell wall degradation and stress tolerance-related proteins, and helpful to the cuticle penetration and host internal environment adaption. In addition, differences in genomic clusters specifically related to secondary metabolites, including the clusters of Indole-NRPS hybrid, T1PKS-NRPS like hybrid, Betalactone, Fungal-Ripp and NRPS-Terpene hybrid, may lead to differences in core virulence-related secondary metabolite genes in M. acridum (18) and M. anisopliae (36).

CONCLUSION

The comparative study provided new insights into the different infection strategies between M. anisopliae and M. acridum, and further facilitate the identification of virulence-related genes for the improvement of mycoinsecticides. © 2023 Society of Chemical Industry.

Enniatin B1: Emerging Mycotoxin and Emerging Issues

Although over the last 10 years several studies have focused on the emerging mycotoxins known as enniatins (ENNs), there is still a lack of knowledge regarding their toxicological effects and the development of a correct risk assessment. This is especially true for enniatin B1 (ENN B1), considered the younger sister of the widely studied enniatin B (ENN B). ENN B1 has been found in several food commodities and, as with other mycotoxins, presents antibacterial and antifungal properties. On the other hand, ENN B1 has shown cytotoxic activity, impairment of the cell cycle, the induction of oxidative stress, and changes in mitochondrial membrane permeabilization, as well as negative genotoxic and estrogenic effects. Overall, considering the paucity of information available regarding ENN B1, further studies are necessary to perform a risk assessment. This review summarizes information on the biological characteristics and toxicological effects of ENN B1 as well as the future challenges that this mycotoxin could present.

Cytochrome P450 isoforms contribution, plasma protein binding, toxicokinetics of enniatin A in rats and in vivo clearance prediction in humans

Emerging mycotoxins, such as enniatin A (ENNA), are becoming a worldwide concern owing to their presence in different types of food and feed. However, comprehensive toxicokinetic data that links intake, exposure and toxicological effects of ENNA has not been elucidated yet. Therefore, the present study investigated the in vitro (rat and human) and in vivo (rat) toxicokinetic properties of ENNA. Towards this, an easily applicable and sensitive bioanalytical method was developed and validated for the estimation of ENNA in rat plasma. ENNA exhibited high plasma protein binding (99%), high hepatic clearance and mainly underwent metabolism via CYP3A4 (74%). The in-house predicted hepatic clearance (54 mL/min/kg) and observed in vivo rat clearance (55 mL/min/kg) were comparable. The predicted in vivo human hepatic clearance was 18 mL/min/kg. ENNA underwent slow absorption (T_max = 4 h) and rapid elimination following oral administration to rats. The absolute oral bioavailability was 47%. The toxicokinetic findings for ENNA from this study will help in designing and interpreting toxicological studies in rats. Besides, these findings could be used in physiologically based toxicokinetic (PBTK) model development for exposure predictions and risk assessment for ENNA in humans.

Cytotoxicity of Aspergillus Section Fumigati Isolates Recovered from Protection Devices Used on Waste Sorting Industry

Safe working conditions must be guaranteed during waste sorting, which is crucial to maximizing recycling and reuse, in order to minimize workers’ exposure to chemical and biological hazards. This study determines the contribution of Aspergillus section Fumigati to the overall cytotoxicity of filtering respiratory protection devices (FRPD) and mechanic protection gloves (MPG) collected in 2019 from different workstations in one waste sorting industry in Portugal. The cytotoxicity of 133 Aspergillus section Fumigati isolates was determined as IC50 in human A549 epithelial lung cells and swine kidney cells, using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Aspergillus section Fumigati cytotoxicity results were compared with previous total cytotoxicity data from FRPD and MPG samples. A significant correlation was detected between the total cytotoxicity of samples and cytotoxicity of Aspergillus section Fumigati isolates in A549 cells (rS = −0.339, p = 0.030). The cytotoxicity of Aspergillus section Fumigati isolates explained 10.7% of the total cytotoxicity of the sample. On the basis of the comparison of cytotoxicity levels, it was possible to determine the contribution of Aspergillus section Fumigati isolates for the total cytotoxicity of protection devices used in the waste sorting industry. The results support in vitro toxicology as a relevant approach in risk assessments regarding cytotoxicity in passive sampling, and thus, useful in determining the contribution of relevant microbial contaminants to overall cytotoxicity. This approach can provide valuable answers in dose/response studies, and support innovations in risk characterization and their translation into occupational policies.

Cytotoxicity of filtering respiratory protective devices from the waste sorting industry: A comparative study between interior layer and exhalation valve

Filtering respiratory protection devices (FRPD) are mandatory for workers to wear in the Portuguese waste-sorting industry. Previous results regarding microbial contamination found on FRPD interior layer raised the question of whether microbial contamination from the exhalation valve would also have cytotoxicity effects. Since the FRPD exhalation valves are very close to workers' nose and mouth, they represent a source of exposure to bioburden by inhalation. This study aimed to evaluate the cytotoxicity of the microbial contamination present in the FRPD exhalation valves. For this purpose, the cytotoxicity effects were determined through the MTT assay in two different cell lines (human A549 epithelial lung cells, and swine kidney cells) and compared with previous results obtained with FRPD interior layers. The contamination present in the FRPD exhalation valves presented some cytotoxicity on epithelial lung cells, suggesting the inhalation route as a potential route of exposure through the use of FRPD in the waste-sorting industry. Half-maximal (50%) inhibitory concentration (IC50) values were lower for FRPD interior layer than exhalation valves in lung cells, with overall cytotoxicity lower in exhalation valves when compared to interior layer (z = -4.455, p = 0.000). Higher bacterial counts in TSA were correlated with lower IC50 values, thus, higher cytotoxicity effect in lung cells. No statistically significant differences were detected among different workplaces.

The Chemical Ecology Approach to Reveal Fungal Metabolites for Arthropod Pest Management

Biorational insecticides (for instance, avermectins, spinosins, azadirachtin, and afidopyropen) of natural origin are increasingly being used in agriculture. The review considers the chemical ecology approach for the search for new compounds with insecticidal properties (entomotoxic, antifeedant, and hormonal) produced by fungi of various ecological groups (entomopathogens, soil saprotrophs, endophytes, phytopathogens, and mushrooms). The literature survey revealed that insecticidal metabolites of entomopathogenic fungi have not been sufficiently studied, and most of the well-characterized compounds show moderate insecticidal activity. The greatest number of substances with insecticidal properties was found to be produced by soil fungi, mainly from the genera Aspergillus and Penicillium. Metabolites with insecticidal and antifeedant properties were also found in endophytic and phytopathogenic fungi. It was noted that insect pests of stored products are mostly low sensitive to mycotoxins. Mushrooms were found to be promising producers of antifeedant compounds as well as insecticidal proteins. The expansion of the number of substances with insecticidal properties detected in prospective fungal species is possible by mining fungal genomes for secondary metabolite gene clusters and secreted proteins with their subsequent activation by various methods. The efficacy of these studies can be increased with high-throughput techniques of extraction of fungal metabolites and their analysis by various methods of chromatography and mass spectrometry.

In vitro screening of 65 mycotoxins for insecticidal potential

The economic losses and threats to human and animal health caused by insects and the pathogens transmitted by them require effective and environmentally-friendly methods of controlling them. One such group of natural biocontrol agents which may be used as biopesticides is that of the entomopathogenic fungi and their toxic secondary metabolites (mycotoxins). The present in vitro work examined the insecticidal potential of 65 commercially-available mycotoxins against the insect Sf-9 cell line. Mammalian Caco-2 and THP-1 cell lines served as reference controls to select insecticidal mycotoxins harmless to mammalian cells. All tested mycotoxins significantly reduced the in vitro proliferation of the Sf-9 cells and evoked morphological changes. Ten of the mycotoxins found to strongly inhibit Sf-9 proliferation also had moderate or no effect on Caco-2 cells. The THP-1 cells were highly resistant to the tested mycotoxins: doses 10³ times higher were needed to affect viability and morphology (1 μg/ml for THP-1 versus 1 ng/ml for Sf-9 and Caco-2). Nine mycotoxins significantly decreased Sf-9 cell proliferation with minor effects on mammalian cells: cyclosporins B and D, cytochalasin E, gliotoxin, HC toxin, paxilline, penitrem A, stachybotrylactam and verruculogen. These may be good candidates for future biopesticide formulations.

The Ribosome-Binding Mode of Trichothecene Mycotoxins Rationalizes Their Structure-Activity Relationships

Trichothecenes are the most prevalent mycotoxins contaminating cereal grains. Some of them are also considered as the virulence factors of Fusarium head blight disease. However, the mechanism behind the structure-activity relationship for trichothecenes remains unexplained. Filling this information gap is a crucial step for developing strategies to manage this large family of mycotoxins in food and feed. Here, we perform an in-depth re-examination of the existing structures of Saccharomyces cerevisiae ribosome complexed with three different trichothecenes. Multiple binding interactions between trichothecenes and 25S rRNA, including hydrogen bonds, nonpolar pi stacking interactions and metal ion coordination interactions, are identified as important binding determinants. These interactions are mainly contributed by the key structural elements to the toxicity of trichothecenes, including the oxygen in the 12,13-epoxide ring and a double bond between C9 and C10. In addition, the C3-OH group also participates in binding. The comparison of three trichothecenes binding to the ribosome, along with their binding pocket architecture, suggests that the substitutions at different positions impact trichothecenes binding in two different patterns. Moreover, the binding of trichothecenes induced conformation changes of several nucleotide bases in 25S rRNA. This then provides a structural framework for understanding the structure-activity relationships apparent in trichothecenes. This study will facilitate the development of strategies aimed at detoxifying mycotoxins in food and feed and at improving the resistance of cereal crops to Fusarium fungal diseases.

Fungal natural products galaxy: Biochemistry and molecular genetics toward blockbuster drugs discovery

Secondary metabolites synthesized by fungi have become a precious source of inspiration for the design of novel drugs. Indeed, fungi are prolific producers of fascinating, diverse, structurally complex, and low-molecular-mass natural products with high therapeutic leads, such as novel antimicrobial compounds, anticancer compounds, immunosuppressive agents, among others. Given that these microorganisms possess the extraordinary capacity to secrete diverse chemical scaffolds, they have been highly exploited by the giant pharma companies to generate small molecules. This has been made possible because the isolation of metabolites from fungal natural sources is feasible and surpasses the organic synthesis of compounds, which otherwise remains a significant bottleneck in the drug discovery process. Here in this comprehensive review, we have discussed recent studies on different fungi (pathogenic, non-pathogenic, commensal, and endophytic/symbiotic) from different habitats (terrestrial and marines), the specialized metabolites they biosynthesize, and the drugs derived from these specialized metabolites. Moreover, we have unveiled the logic behind the biosynthesis of vital chemical scaffolds, such as NRPS, PKS, PKS-NRPS hybrid, RiPPS, terpenoids, indole alkaloids, and their genetic mechanisms. Besides, we have provided a glimpse of the concept behind mycotoxins, virulence factor, and host immune response based on fungal infections.

Cosmosporasides F-H, three new sugar alcohol conjugated acyclic sesquiterpenes from a Fusarium oxysporum fungus

Three new sugar alcohol conjugated acyclic sesquiterpenes, cosmosporasides F-H (1-3), were isolated from the fermented cultures of Fusarium oxysporum SC0002. Their structures were elucidated by extensive analysis of spectroscopic data, including ¹H-¹³C long-range coupling constants (J_C,H). Their antibacterial, cytotoxic and anti-inflammatory activities were evaluated.

Effects of Entomopathogenic Fungi on Individuals as Well as Groups of Workers and Immatures of Atta sexdens rubropilosa Leaf-Cutting Ants

Simple Summary

The used active ingredient sulfluramid for toxic baits for the control of leaf-cutting ants has been included in Annex B of the Stockholm Convention on Persistent Organic Pollutants. The use of entomopathogenic fungi to control these insects has shown promising results, Trichoderma harzianum showed high pathogenicity against A. sexdens rubropilosa larvae and pupae, leading to a faster mortality and a decrease in survival rates. Beauveria bassiana was responsible for causing faster worker mortality and lower survival rates. An individual contaminated with B. bassiana or T. harzianum in a group decreases its survival rate, supporting the hypothesis that entomopathogenic fungi are efficient in controlling leaf-cutting ants when contaminated workers are allocated to groups of healthy workers.

Abstract

In 2009, sulfluramid, the main ingredient in toxic baits for leaf-cutting ant control, was included in Annex B of the Stockholm Convention on Persistent Organic Pollutants. This resulted in interest in the use of entomopathogenic fungi such as Beauveria bassiana and Trichoderma harzianum for leaf-cutting ant control. The efficiency of these fungi in controlling these insects and the way that ants react individually or in group to the biological risks posed by these fungi is poorly understood. For this reason, we assessed the effects of B. bassiana and T. harzianum on Atta sexdens rubropilosa larvae, pupae and workers. Moreover, we investigated whether the number of contaminated individuals within a group has an influence in controlling the spread of fungi among workers. We found that the fungus T. harzianum showed high pathogenicity against A. sexdens rubropilosa larvae and pupae, leading to faster mortality and a survival rates. On the other hand, the fungus B. bassiana was responsible for causing faster worker mortality and lower survival rates. In addition, we observed that an increase in individuals contaminated with B. bassiana or T. harzianum in the group decreases its survival rate. The results support the hypothesis that entomopathogenic fungi are efficient in controlling leaf-cutting ants when contaminated workers are allocated to groups of healthy workers.

Cytotoxic effect of filtering respiratory protective devices from the waste sorting industry: is in vitro toxicology useful for risk characterization?

The use of Filtering Respiratory Protective Devices (FRPD) is mandatory in Portugal to protect workers from the waste industry of harmful exposures. Deleterious health effects of exposure to bioburden via inhalation and/or ingestion include respiratory symptoms and nephrotoxicity. Between January and February 2019, 118 FRPD samples were collected in one waste sorting industry and characterized regarding microbial contamination and cytotoxicity, defined as cell metabolic activity, through the MTT colorimetric assay (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide). Cytotoxic effect was classified according to percentage of extinction values with respect to the control group, as follows: absent (≥90); low (80%-90%, +); medium (60%-79%, ++); and high (below 60%, +++). For 113 samples the MTT assay revealed a cytotoxic effect in A549 cells, of which 81 presented high cytotoxicity. In SK cells, a cytotoxic effect was observed in 56 samples, of which five displayed a high cytotoxic effect. Several moderate (p < 0.05) to strong (p < 0.01) correlations were found between higher bacterial and fungal counts both in interior layers (fungi and bacteria) and in exhalation valves (fungi) of FRPD samples and reduced cell metabolic activity of SK cells. On the basis of the obtained results for the cytotoxic effect of FRPD samples on two different cells lines, it was determined that A549 cells exhibited a cytotoxic effect for a higher number of FRPD, whereas the SK cells model correlated better with the other assessed parameters, namely, bacterial and fungal counts and conditions of FRPD use. Although the results are not conclusive on the most appropriate cell line to assess FRPD cytotoxicity, they reinforce the importance of in vitro toxicology in exposure assessments to determine the cytotoxicity of mixtures of contaminants, for better risk characterization and selection of appropriate risk management measures.

Interactions Between Two Invertebrate Pathogens: An Endophytic Fungus and an Externally Applied Bacterium

The members of family Noctuidae exist in diverse environments and many species from this group are of agriculture importance, particularly Helicoverpa spp. Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is a major pest of many legumes and cereal crops. Due to environmental and regulatory concerns, safe alternatives to broad spectrum chemical insecticides are needed for the control of key noctuid pests such as H. armigera. A strain of Beauveria bassiana (Cordycipitaceae: Hypocreales) was evaluated for its ability to colonize endophytically in chickpea plants, and its effectiveness against second (L2) and fourth (L4) larval instars of H. armigera. B. bassiana was inoculated to chickpea plants through injection and endophytic establishment was confirmed by re-isolating the fungi from leaf samples. A detached leaf assay was used to evaluate pathogenicity. Bacillus thuringiensis was also applied to both larval stages through leaf dip method. In a novel approach, combined treatments of bacteria and endophytic fungi were compared with single-pathogen treatments. Relative to the single treatments, the combined pathogen treatments exhibited an increase in larval mortality, and decrease in pupation, adult emergence and egg eclosion. Specifically, synergistic effects on mortality were observed when larvae were exposed to simultaneous application of B. bassiana (1 × 108 conidia ml-1) with B. thuringiensis (0.75 μg ml-1). Both instars exhibited varying level of growth, development, frass production, diet consumption and fecundity when exposed to the chickpea leaves inoculated with endophytic B. bassiana and dipped with sub-lethal doses of B. thuringiensis. These findings indicate that the integrated application of endophytic colonized B. bassiana and B. thuringiensis can be effectively used against H. armigera.

Beauvericin and Enniatins: In Vitro Intestinal Effects

Food and feed contamination by emerging mycotoxins beauvericin and enniatins is a worldwide health problem and a matter of great concern nowadays, and data on their toxicological behavior are still scarce. As ingestion is the major route of exposure to mycotoxins in food and feed, the gastrointestinal tract represents the first barrier encountered by these natural contaminants and the first structure that could be affected by their potential detrimental effects. In order to perform a complete and reliable toxicological evaluation, this fundamental site cannot be disregarded. Several in vitro intestinal models able to recreate the different traits of the intestinal environment have been applied to investigate the various aspects related to the intestinal toxicity of emerging mycotoxins. This review aims to depict an overall and comprehensive representation of the in vitro intestinal effects of beauvericin and enniatins in humans from a species-specific perspective. Moreover, information on the occurrence in food and feed and notions on the regulatory aspects will be provided.

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.

Tryptamine accumulation caused by deletion of MrMao-1 in Metarhizium genome significantly enhances insecticidal virulence

Metarhizium is a group of insect-pathogenic fungi that can produce insecticidal metabolites, such as destruxins. Interestingly, the acridid-specific fungus Metarhizium acridum (MAC) can kill locusts faster than the generalist fungus Metarhizium robertsii (MAA) even without destruxin. However, the underlying mechanisms of different pathogenesis between host-generalist and host-specialist fungi remain unknown. This study compared transcriptomes and metabolite profiles to analyze the difference in responsiveness of locusts to MAA and MAC infections. Results confirmed that the detoxification and tryptamine catabolic pathways were significantly enriched in locusts after MAC infection compared with MAA infection and that high levels of tryptamine could kill locusts. Furthermore, tryptamine was found to be capable of activating the aryl hydrocarbon receptor of locusts (LmAhR) to produce damaging effects by inducing reactive oxygen species production and immune suppression. Therefore, reducing LmAhR expression by RNAi or inhibitor (SR1) attenuates the lethal effects of tryptamine on locusts. In addition, MAA, not MAC, possessed the monoamine oxidase (Mao) genes in tryptamine catabolism. Hence, deleting MrMao-1 could increase the virulence of generalist MAA on locusts and other insects. Therefore, our study provides a rather feasible way to design novel mycoinsecticides by deleting a gene instead of introducing any exogenous gene or domain.

Metabolism of selected model substrates and insecticides by recombinant CYP6FD encoded by its gene predominately expressed in the brain of Locusta migratoria

The migratory locust, Locusta migartoria, is a major agricultural insect pest and its resistance to insecticides is becoming more prevalent. Cytochrome P450 monooxygenases (CYPs) are important enzymes for biotransformations of various endogenous and xenobiotic substances. These enzymes play a major role in developing insecticide resistance in many insect species. In this study, we heterologously co-expressed a CYP enzyme (CYP6FD1) and cytochrome P450 reductase (CPR) from L. migartoria in Sf9 insect cells. The recombinant enzymes were assayed for metabolic activity towards six selected model substrates (luciferin-H, luciferin-Me, luciferin-Be, luciferin-PFBE, luciferin-CEE and 7-ethoxycoumarin), and four selected insecticides (deltamethrin, chlorpyrifos, carbaryl and methoprene). Recombinant CYP6FD1 showed activity towards 7-ethoxycoumarin and luciferin-Me, but no detectable activity towards the other luciferin derivatives. Furthermore, the enzyme efficiently oxidized deltamethrin to hydroxydeltamethrin through an aromatic hydroxylation in a time-dependent manner. However, the enzyme did not show any detectable activity towards the other three insecticides. Our results provide direct evidence that CYP6FD1 is capable of metabolizing deltamethrin. This work is a step towards a more complete characterization of the catalytic capabilities of CYP6FD1 and other xenobiotic metabolizing CYP enzymes in L. migratoria.

Emerging Fusarium Mycotoxins Fusaproliferin, Beauvericin, Enniatins, and Moniliformin in Serbian Maize

Emerging mycotoxins such as moniliformin (MON), enniatins (ENs), beauvericin (BEA), and fusaproliferin (FUS) may contaminate maize and negatively influence the yield and quality of grain. The aim of this study was to determine the content of emerging Fusarium mycotoxins in Serbian maize from the 2016, 2017, and 2018 harvests. A total of 190 samples from commercial maize production operations in Serbia were analyzed for the presence of MON, ENs, BEA, and FUS using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The obtained results were interpreted together with weather data from each year. MON, BEA, and FUS were major contaminants, while other emerging mycotoxins were not detected or were found in fewer samples (<20%). Overall contamination was highest in 2016 when MON and BEA were found in 50–80% of samples. In 2017 and 2018, high levels of MON, FUS, and BEA were detected in regions with high precipitation and warm weather during the silking phase of maize (July and the beginning of August), when the plants are most susceptible to Fusarium infections. Since environmental conditions in Serbia are favorable for the occurrence of mycotoxigenic fungi, monitoring Fusarium toxins is essential for the production of safe food and feed.

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 6th 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.

Establishment and characterization of a caudal fin-derived cell line, AOF, from the Oscar, Astronotus ocellatus

Astronotus ocellatus, commonly called the oscar, is one of the popular cichlids among aquarium hobby. The present study deals with the development and characterization of a new cell line from caudal fin of A. ocellatus. The cell line was cultured in Leibovitz's L-15 medium supplemented with 10% fetal bovine serum at 28 °C. The optimum temperature and FBS concentration for cell growth were tested with temperature ranges from 20 to 37 °C and FBS concentrations of 5-20% at 28 °C. The Astronotus ocellatus fin cell line has been subcultured 45 times since its development and the modal chromosome number (2n) is 48. The cell line is composed mainly of epithelial cells as confirmed by immunocytological technique using anti-cytokeratin antibodies. The cell line was cryopreserved at different passage levels and the revival efficiency showed 80% survival rate. Partial sequence amplification and sequencing of two genes, mitochondrial 16S ribosomal RNA and cytochrome oxidase I, confirmed the origin of cell line. The cell line did not show Mycoplasma contamination. The cells showed good transfection efficiency when transfected with 2 μg of pAcGFP1-N1 expression vector. The extracellular products of fish bacterial pathogens viz., Aeromonas hydrophila and A. caviae, were cytotoxic to AOF cells but were not susceptible to Cyprinid herpes virus 2. The development of AOF cell line will have significant applications in fish virology and will prove useful to isolate pathogens in the event of sudden viral disease outbreak and for the development of vaccines and diagnostic kits.

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.

Assessment of cytotoxic and genotoxic effects of enniatin-A in vitro

Enniatin A (EN-A) is a Fusarium mycotoxin which is a common contaminant in grains and especially in maize and it causes serious loss of product. The aim of this study was to investigate the cytotoxic effects using 3-(4,5-dimethylthiazolyl-2)-2,5 diphenyltetrazolium bromide (MTT) assay in human cervix carcinoma (HeLa) cell line, and genotoxic effects of EN-A using chromosome aberrations (CAs), sister chromatid exchanges (SCEs), micronuclei (MN) and comet assays in human lymphocytes. The cells were treated with 0.07, 0.14, 0.29, 0.57, 1.15, 2.29, 4.59 and 9.17 μM concentrations of EN-A. It exhibited cytotoxic effects in HeLa cell lines especially when the concentrations were increased. The half-inhibitory value (IC₅₀) was determined as 1.15 μM concentration for 24 h and 0.57 μM concentration for 48 h. However, EN-A failed to affect the frequency of CAs, SCEs and MN in human lymphocytes. Only a slight increase was observed in the frequency of SCEs at 0.57 μM concentration over 48 h. The replication (RI) and nuclear division (NDI) indices were not affected. On the contrary, EN-A decreased the mitotic index (MI) significantly at all concentrations compared to the negative control and solvent control (except at 0.29 μM for 24 h, and except at 0.14, 0.29 and 0.57 μM for 48 h). Treatments over 2.29 μM showed toxic effects in human lymphocytes. EN-A significantly increased comet tail intensity (except at 0.07 and 0.57 μM) in isolated human lymphocytes. The results of this study demonstrate that EN-A has an obvious cytotoxic effect especially when the EN-A concentration was increased. In addition, EN-A could exhibit a mild genotoxic effect.

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.

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.

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.

Beauvericin, a cyclic peptide, inhibits inflammatory responses in macrophages by inhibiting the NF-κB pathway

Beauvericin (BEA), a cyclic hexadepsipeptide produced by the fungus Beauveria bassiana, is known to have anti-cancer, anti-inflammatory, and anti-microbial actions. However, how BEA suppresses macrophage-induced inflammatory responses has not been fully elucidated. In this study, we explored the anti-inflammatory properties of BEA and the underlying molecular mechanisms using lipopolysaccharide (LPS)-treated macrophage-like RAW264.7 cells. Levels of nitric oxide (NO), mRNA levels of transcription factors and the inflammatory genes inducible NO synthase (iNOS) and interleukin (IL)-1, and protein levels of activated intracellular signaling molecules were determined by Griess assay, semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), luciferase reporter gene assay, and immunoblotting analysis. BEA dose-dependently blocked the production of NO in LPS-treated RAW264.7 cells without inducing cell cytotoxicity. BEA also prevented LPS-triggered morphological changes. This compound significantly inhibited nuclear translocation of the NF-κB subunits p65 and p50. Luciferase reporter gene assays demonstrated that BEA suppresses MyD88-dependent NF-κB activation. By analyzing upstream signaling events for NF-κB activation and overexpressing Src and Syk, these two enzymes were revealed to be targets of BEA. Together, these results suggest that BEA suppresses NF-κB-dependent inflammatory responses by suppressing both Src and Syk.

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.

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.

A new fish cell line derived from the caudal fin of freshwater angelfish Pterophyllum scalare: development and characterization

In this study, a new cell line derived from the caudal fin of the freshwater angelfish Pterophyllum scalare was developed and characterized. The cell line was designated angelfish fin (AFF) and subcultured 44 times since its development. These cells grew well in Leibovitz's -15 medium supplemented with 10% foetal bovine saline (FBS) at 28° C and the modal chromosome number (2n) was 48. The AFF cell-line is mainly comprised of epithelial cells as confirmed by immunocytological technique using anti-cytokeratin antibodies, an epithelial cell marker. This cell line was tested for growth in a temperatures range from 20 to 37° C and at various FBS concentrations of 5-20% at 28° C. The cell line was cryopreserved at different passage levels and revived successfully with 80% survival rate. Polymerase chain reaction amplification and sequencing of partial mitochondrial 16s rRNA and coI genes confirmed that the AFF cell-line originated from angelfish. Mycoplasma sp. contamination was not detected in AFF cells and checked by Hoechst 33258 fluorescence staining. At the 42nd passage the cells were transfected with 2 μg of pAcGFP1-N1 expression vector. The AFF cells exhibited cytotoxic effects when exposed to the bacterial extra cellular products from Serratia marcescens and Proteus hauseri. The AFF cells and cells from kidney and brain did not show cytopathic effect when exposed to cyprinid herpes virus2 and viral nervous necrosis virus. The newly developed AFF cell line will be useful for the isolation of viruses affecting angelfishes, such as iridoviruses, in the future.

Isolation and Identification of the Antimicrobial Agent Beauvericin from the Endophytic Fusarium oxysporum 5-19 with NMR and ESI-MS/MS

Endophytic microbe has been proved to be one of rich sources of bioactive natural products with potential application for new drug and pesticide discovery. One cyclodepsipeptide, beauvericin, was firstly isolated from the fermentation broth of Fusarium oxysporum 5-19 endophytic on Edgeworthia chrysantha Linn. Its chemical structure was unambiguously identified by a combination of spectroscopic methods, such as HRESI-MS and (1)H and (13)C NMR. ESI-MS/MS was successfully used to elucidate the splitting decomposition route of the positive molecule ion of beauvericin. Antimicrobial results showed that this cyclodepsipeptide had inhibitory effect on three human pathogenic microbes, Candida albicans, Escherichia coli, and Staphylococcus aureus. In particular, beauvericin exhibited the strongest antimicrobial activity against S. aureus with MIC values of 3.91 μM, which had similar effect with that of the positive control amoxicillin.

Mouse tissue distribution and persistence of the food-born fusariotoxins Enniatin B and Beauvericin

The fusariotoxins Enniatin B (Enn B) and Beauvericin (Bea) have recently aroused interest as food contaminants and as potential anticancer drugs. However, limited data are available about their toxic profile. Aim of this study was to investigate their pharmacological behavior in vivo and their persistence in mice. Therefore, liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to analyze the distribution of Enn B and Bea in selected tissue samples and biological fluids originating from mice treated intraperitoneally with these cyclohexadepsipeptides. Overall, no toxicological signs during life time or pathological changes were observed. Moreover, both fusariotoxins were found in all tissues and serum but not in urine. Highest amounts were measured in liver and fat demonstrating the moleculeś tendency to bioaccumulate in lipophilic tissues. While for Bea no metabolites could be detected, for Enn B three phase I metabolites (dioxygenated-Enn B, mono- and di-demethylated-Enn B) were found in liver and colon, with dioxygenated-Enn B being most prominent. Consequently, contribution of hepatic as well as intestinal metabolism seems to be involved in the overall metabolism of Enn B. Thus, despite their structural similarity, the metabolism of Enn B and Bea shows distinct discrepancies which might affect long-term effects and tolerability in humans.

Development of a Rapid LC-MS/MS Method for the Determination of Emerging Fusarium mycotoxins Enniatins and Beauvericin in Human Biological Fluids

A novel method for the simultaneous determination of enniatins A, A1, B and B1 and beauvericin, both in human urine and plasma samples, was developed and validated. The method consisted of a simple and easy pretreatment, specific for each matrix, followed by solid phase extraction (SPE) and detection by high performance liquid chromatography-tandem mass spectrometry with an electrospray ion source. The optimized SPE method was performed on graphitized carbon black cartridges after suitable dilution of the extracts, which allowed high mycotoxin absolute recoveries (76%–103%) and the removal of the major interferences from the matrix. The method was extensively evaluated for plasma and urine samples separately, providing satisfactory results in terms of linearity (R² of 0.991–0.999), process efficiency (>81%), trueness (recoveries between 85% and 120%), intra-day precision (relative standard deviation, RSD < 18%), inter-day precision (RSD < 21%) and method quantification limits (ranging between 20 ng·L⁻¹ and 40 ng·L⁻¹ in plasma and between 5 ng·L⁻¹ and 20 ng·L⁻¹ in urine). Finally, the highly sensitive validated method was applied to some urine and plasma samples from different donors.

Establishment of a new cell line from the heart of giant grouper, Epinephelus lanceolatus (Bloch), and its application in toxicology and virus susceptibility

A new marine fish cell line, derived from the heart of giant grouper, Epinephelus lanceolatus (Bloch), was established and characterized. The cell line was designated as ELGH and subcultured with more than 60 passages. The ELGH cells were mainly composed of fibroblast-like cells and multiplied well in Leibovitz's L-15 medium supplemented with 10% foetal bovine serum (FBS) at 28 °C. Chromosome analysis indicated that the modal chromosome number was 48. The fluorescent signals were detected in ELGH when transfected with green fluorescent protein reporter plasmids. The 50% cytotoxic concentration (CC50 ) of the extracellular products (ECPs) from Streptococcus iniae and Vibrio alginolyticus E333 on ELGH cells was 60.02 and 12.49 μg mL(-1), respectively. Moreover, the ELGH cells showed susceptibility to Singapore grouper iridovirus (SGIV), but not to soft-shelled turtle iridovirus (STIV), red-spotted grouper nervous necrosis virus (RGNNV) and spring viremia of carp virus (SVCV), which was demonstrated by the presence of a severe cytopathic effect (CPE) and increased viral titres. In addition, electron microscopy observation showed that abundant virus particles were present in the infected cells. Taken together, our data above provided the potential utility of ELGH cells for transgenic and genetic manipulation, as well as cytotoxicity testing and virus pathogenesis.

Insect eggs induce a systemic acquired resistance in Arabidopsis

Although they constitute an inert stage of the insect's life, eggs trigger plant defences that lead to egg mortality or attraction of egg parasitoids. We recently found that salicylic acid (SA) accumulates in response to oviposition by the Large White butterfly Pieris brassicae, both in local and systemic leaves, and that plants activate a response that is similar to the recognition of pathogen-associated molecular patterns (PAMPs), which are involved in PAMP-triggered immunity (PTI). Here we discovered that natural oviposition by P. brassicae or treatment with egg extract inhibit growth of different Pseudomonas syringae strains in Arabidopsis through the activation of a systemic acquired resistance (SAR). This egg-induced SAR involves the metabolic SAR signal pipecolic acid, depends on ALD1 and FMO1, and is accompanied by a stronger induction of defence genes upon secondary infection. Although P. brassicae larvae showed a reduced performance when feeding on Pseudomonas syringae-infected plants, this effect was less pronounced when infected plants had been previously oviposited. Altogether, our results indicate that egg-induced SAR might have evolved as a strategy to prevent the detrimental effect of bacterial pathogens on feeding larvae.

Unraveling the mechanisms involved in zearalenone-mediated toxicity in permanent fish cell cultures

The world-wide occurrence of zearalenone (ZEN) as a contaminant in feed for farm animals and fish requires the evaluation of toxicity mechanisms of action of ZEN. The present study investigates possible metabolization of ZEN in fish cell lines suggesting that mainly glucuronidation takes place. It demonstrates that concentrations up to 20,000 ng ml(-1) ZEN are capable of influencing cell viability in permanent fish cell cultures in a dose-response manner with different response patterns between the five tested cell lines, whereby lysosomes appeared to be the main target of ZEN. ZEN toxicity is often discussed in the context of oxidative stress. Our study shows a biphasic response of the cell lines when reactive oxygen species (ROS) production is monitored. Damage in cells was observed by measuring lipid peroxidation, DNA strand breaks, and alterations of intracellular glutathione levels. Metabolization of ZEN, especially at concentrations above 7500 ng ml(-1) ZEN, does not prevent cytotoxicity. ZEN as an estrogenic compound may involve processes mediated by binding to estrogen receptors (ER). Since one cell line showed no detectable expression of ER, an ER-mediated pathway seems to be unlikely in these cells. This confirms a lysosomal pathway as a main target of ZEN in fish cells.

Effect of fungal colonization of wheat grains with Fusarium spp. on food choice, weight gain and mortality of meal beetle larvae (Tenebrio molitor)

Species of Fusarium have significant agro-economical and human health-related impact by infecting diverse crop plants and synthesizing diverse mycotoxins. Here, we investigated interactions of grain-feeding Tenebrio molitor larvae with four grain-colonizing Fusarium species on wheat kernels. Since numerous metabolites produced by Fusarium spp. are toxic to insects, we tested the hypothesis that the insect senses and avoids Fusarium-colonized grains. We found that only kernels colonized with F. avenaceum or Beauveria bassiana (an insect-pathogenic fungal control) were avoided by the larvae as expected. Kernels colonized with F. proliferatum, F. poae or F. culmorum attracted T. molitor larvae significantly more than control kernels. The avoidance/preference correlated with larval feeding behaviors and weight gain. Interestingly, larvae that had consumed F. proliferatum- or F. poae-colonized kernels had similar survival rates as control. Larvae fed on F. culmorum-, F. avenaceum- or B. bassiana-colonized kernels had elevated mortality rates. HPLC analyses confirmed the following mycotoxins produced by the fungal strains on the kernels: fumonisins, enniatins and beauvericin by F. proliferatum, enniatins and beauvericin by F. poae, enniatins by F. avenaceum, and deoxynivalenol and zearalenone by F. culmorum. Our results indicate that T. molitor larvae have the ability to sense potential survival threats of kernels colonized with F. avenaceum or B. bassiana, but not with F. culmorum. Volatiles potentially along with gustatory cues produced by these fungi may represent survival threat signals for the larvae resulting in their avoidance. Although F. proliferatum or F. poae produced fumonisins, enniatins and beauvericin during kernel colonization, the larvae were able to use those kernels as diet without exhibiting increased mortality. Consumption of F. avenaceum-colonized kernels, however, increased larval mortality; these kernels had higher enniatin levels than F. proliferatum or F. poae-colonized ones suggesting that T. molitor can tolerate or metabolize those toxins.