Toxins

11 pages, 1403 KiB

Open AccessEditor’s ChoiceArticle

Evidence for Naturally Produced Beauvericins Containing N-Methyl-Tyrosine in Hypocreales Fungi

by Monika Urbaniak, Łukasz Stępień and Silvio Uhlig

Toxins 2019, 11(3), 182; https://doi.org/10.3390/toxins11030182 - 26 Mar 2019

Cited by 15 | Viewed by 4353

Beauvericin is a depsipeptide mycotoxin. The production of several beauvericin analogues has previously been shown among various genera among Hypocreales fungi. This includes so-called beauvenniatins, in which one or more N-methyl-phenylalanine residues is exchanged with other amino acids. In addition, a range [...] Read more.

Beauvericin is a depsipeptide mycotoxin. The production of several beauvericin analogues has previously been shown among various genera among Hypocreales fungi. This includes so-called beauvenniatins, in which one or more N-methyl-phenylalanine residues is exchanged with other amino acids. In addition, a range of “unnatural” beauvericins has been prepared by a precursor addition to growth medium. Our aim was to get insight into the natural production of beauvericin analogues among different Hypocreales fungi, such as Fusarium and Isaria spp. In addition to beauvericin, we tentatively identified six earlier described analogues in the extracts; these were beauvericin A and/or its structural isomer beauvericin F, beauvericin C, beauvericin J, beauvericin D, and beauvenniatin A. Other analogues contained at least one additional oxygen atom. We show that the additional oxygen atom(s) were due to the presence of one to three N-methyl-tyrosine moieties in the depsipeptide molecules by using different liquid chromatography–mass spectrometry-based approaches. In addition, we also tentatively identified a beauvenniatin that contained N-methyl-leucine, which we named beauvenniatin L. This compound has not been reported before. Our data show that N-methyl-tyrosine containing beauvericins may be among the major naturally produced analogues in certain fungal strains. Full article

(This article belongs to the Special Issue Fungal Infestations in Humans, Animals, Crops)

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16 pages, 2045 KiB

Open AccessEditor’s ChoiceArticle

Molecular Docking and Dynamics Simulation Studies Predict Munc18b as a Target of Mycolactone: A Plausible Mechanism for Granule Exocytosis Impairment in Buruli Ulcer Pathogenesis

by Samuel K. Kwofie, Bismark Dankwa, Kweku S. Enninful, Courage Adobor, Emmanuel Broni, Alfred Ntiamoah and Michael D. Wilson

Toxins 2019, 11(3), 181; https://doi.org/10.3390/toxins11030181 - 25 Mar 2019

Cited by 31 | Viewed by 6788

Abstract

Ulcers due to infections with Mycobacterium ulcerans are characterized by complete lack of wound healing processes, painless, an underlying bed of host dead cells and undermined edges due to necrosis. Mycolactone, a macrolide produced by the mycobacterium, is believed to be the toxin [...] Read more.

Ulcers due to infections with Mycobacterium ulcerans are characterized by complete lack of wound healing processes, painless, an underlying bed of host dead cells and undermined edges due to necrosis. Mycolactone, a macrolide produced by the mycobacterium, is believed to be the toxin responsible. Of interest and relevance is the knowledge that Buruli ulcer (BU) patients remember experiencing trauma previously at the site of the ulcers, suggesting an impairment of wound healing processes, the plausible effect due to the toxin. Wound healing processes involve activation of the blood platelets to release the contents of the dense granules mainly serotonin, calcium ions, and ADP/ATP by exocytosis into the bloodstream. The serotonin release results in attracting more platelets and mast cells to the wound site, with the mast cells also undergoing degranulation, releasing compounds into the bloodstream by exocytosis. Recent work has identified interference in the co-translational translocation of many secreted proteins via the endoplasmic reticulum and cell death involving Wiskott-Aldrich syndrome protein (WASP), Sec61, and angiotensin II receptors (AT2R). We hypothesized that mycolactone by being lipophilic, passively crosses cell membranes and binds to key proteins that are involved in exocytosis by platelets and mast cells, thus inhibiting the initiation of wound healing processes. Based on this, molecular docking studies were performed with mycolactone against key soluble n-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins and regulators, namely Vesicle-associated membrane protein (VAMP8), Synaptosomal-associated protein (SNAP23, syntaxin 11, Munc13-4 (its isoform Munc13-1 was used), and Munc18b; and also against known mycolactone targets (Sec61, AT2R, and WASP). Munc18b was shown to be a plausible mycolactone target after the molecular docking studies with binding affinity of −8.5 kcal/mol. Structural studies and molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) binding energy calculations of the mycolactone and Munc18b complex was done with 100 ns molecular dynamics simulations using GROMACS. Mycolactone binds strongly to Munc18b with an average binding energy of −247.571 ± 37.471 kJ/mol, and its presence elicits changes in the structural conformation of the protein. Analysis of the binding interactions also shows that mycolactone interacts with Arg405, which is an important residue of Munc18b, whose mutation could result in impaired granule exocytosis. These findings consolidate the possibility that Munc18b could be a target of mycolactone. The implication of the interaction can be experimentally evaluated to further understand its role in granule exocytosis impairment in Buruli ulcer. Full article

(This article belongs to the Special Issue Mycolactone: Lipid-Like Immunosuppressive Toxin of Buruli Ulcer)

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10 pages, 431 KiB

Open AccessEditor’s ChoiceShort Communication

Reduction of Mycotoxins during Fermentation of Whole Grain Sorghum to Whole Grain Ting (a Southern African Food)

by Oluwafemi Ayodeji Adebo, Eugenie Kayitesi and Patrick Berka Njobeh

Toxins 2019, 11(3), 180; https://doi.org/10.3390/toxins11030180 - 25 Mar 2019

Cited by 42 | Viewed by 4539

Abstract

Mycotoxins are fungal secondary metabolites that pose health risks to exposed individuals, requiring necessary measures to reduce them. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), mycotoxins were quantified in whole grain sorghum and ting subsequently derived from two sorghum varieties (high and low tannin). [...] Read more.

Mycotoxins are fungal secondary metabolites that pose health risks to exposed individuals, requiring necessary measures to reduce them. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), mycotoxins were quantified in whole grain sorghum and ting subsequently derived from two sorghum varieties (high and low tannin). The whole grain (WG) ting samples were obtained by fermenting sorghum with Lactobacillus fermentum strains (FUA 3165 and FUA 3321). Naturally (spontaneously) fermented WG-ting under the same conditions were equally analysed. Among the mycotoxins investigated, fumonisin B₁ (FB₁), B₂ (FB₂), B₃ (FB₃), T-2 toxin (T-2), zearalenone (ZEA), alpha-zearalenol (α-ZOL) and beta-zearalenol (β-ZOL) were detected in sorghum. Results obtained showed that mycotoxin concentrations significantly (p ≤ 0.05) reduced after fermentation. In particular, L. fermentum FUA 3321 showed the capability to significantly (p ≤ 0.05) reduce all the mycotoxins by 98% for FB₁, 84% for T-2 and up to 82% for α-ZOL, compared to raw low tannin sorghum. Fermenting with the L. fermentum strains showed potential to effectively reduce mycotoxin contamination in whole grain ting. Thus, we recommended L. fermentum FUA 3321 in particular to be used as a potential starter culture in sorghum fermentation. Full article

(This article belongs to the Section Mycotoxins)

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18 pages, 2021 KiB

Open AccessArticle

The Development of a qPCR Assay to Measure Aspergillus flavus Biomass in Maize and the Use of a Biocontrol Strategy to Limit Aflatoxin Production

by Alfred Mitema, Sheila Okoth and Suhail M. Rafudeen

Toxins 2019, 11(3), 179; https://doi.org/10.3390/toxins11030179 - 25 Mar 2019

Cited by 12 | Viewed by 4387 | Correction

Abstract

Aspergillus flavus colonisation of maize can produce mycotoxins that are detrimental to both human and animal health. Screening of maize lines, resistant to A. flavus infection, together with a biocontrol strategy, could help minimize subsequent aflatoxin contamination. We developed a qPCR assay to [...] Read more.

Aspergillus flavus colonisation of maize can produce mycotoxins that are detrimental to both human and animal health. Screening of maize lines, resistant to A. flavus infection, together with a biocontrol strategy, could help minimize subsequent aflatoxin contamination. We developed a qPCR assay to measure A. flavus biomass and showed that two African maize lines, GAF4 and KDV1, had different fungal loads for the aflatoxigenic isolate (KSM014), fourteen days after infection. The qPCR assay revealed no significant variation in A. flavus biomass between diseased and non-diseased maize tissues for GAF4, while KDV1 had a significantly higher A. flavus biomass (p < 0.05) in infected shoots and roots compared to the control. The biocontrol strategy using an atoxigenic isolate (KSM012) against the toxigenic isolate (KSM014), showed aflatoxin production inhibition at the co-infection ratio, 50:50 for both maize lines (KDV1 > 99.7% and GAF ≥ 69.4%), as confirmed by bioanalytical techniques. As far as we are aware, this is the first report in Kenya where the biomass of A. flavus from maize tissue was detected and quantified using a qPCR assay. Our results suggest that maize lines, which have adequate resistance to A. flavus, together with the appropriate biocontrol strategy, could limit outbreaks of aflatoxicoses. Full article

(This article belongs to the Special Issue Biological Control and Post-Harvest Detoxification of Mycotoxins as Strategies to Reduce the Impact of Mycotoxins)

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19 pages, 640 KiB

Open AccessEditor’s ChoiceReview

Staphylococcal Superantigens: Pyrogenic Toxins Induce Toxic Shock

by Teresa Krakauer

Toxins 2019, 11(3), 178; https://doi.org/10.3390/toxins11030178 - 23 Mar 2019

Cited by 80 | Viewed by 9268

Abstract

Staphylococcal enterotoxin B (SEB) and related superantigenic toxins produced by Staphylococcus aureus are potent activators of the immune system. These protein toxins bind to major histocompatibility complex (MHC) class II molecules and specific Vβ regions of T-cell receptors (TCRs), resulting in the activation [...] Read more.

Staphylococcal enterotoxin B (SEB) and related superantigenic toxins produced by Staphylococcus aureus are potent activators of the immune system. These protein toxins bind to major histocompatibility complex (MHC) class II molecules and specific Vβ regions of T-cell receptors (TCRs), resulting in the activation of both monocytes/macrophages and T lymphocytes. The bridging of TCRs with MHC class II molecules by superantigens triggers an early “cytokine storm” and massive polyclonal T-cell proliferation. Proinflammatory cytokines, tumor necrosis factor α, interleukin 1 (IL-1), IL-2, interferon γ (IFNγ), and macrophage chemoattractant protein 1 elicit fever, inflammation, multiple organ injury, hypotension, and lethal shock. Upon MHC/TCR ligation, superantigens induce signaling pathways, including mitogen-activated protein kinase cascades and cytokine receptor signaling, which results in NFκB activation and the phosphoinositide 3-kinase/mammalian target of rapamycin pathways. In addition, gene profiling studies have revealed the essential roles of innate antimicrobial defense genes in the pathogenesis of SEB. The genes expressed in a murine model of SEB-induced shock include intracellular DNA/RNA sensors, apoptosis/DNA damage-related molecules, endoplasmic reticulum/mitochondrial stress responses, immunoproteasome components, and IFN-stimulated genes. This review focuses on the signaling pathways induced by superantigens that lead to the activation of inflammation and damage response genes. The induction of these damage response genes provides evidence that SEB induces danger signals in host cells, resulting in multiorgan injury and toxic shock. Therapeutics targeting both host inflammatory and cell death pathways can potentially mitigate the toxic effects of staphylococcal superantigens. Full article

(This article belongs to the Special Issue Toxins and Immunology)

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18 pages, 1956 KiB

Open AccessArticle

Targeted Mass Spectrometry Analysis of Clostridium perfringens Toxins

by Miloslava Duracova, Jana Klimentova, Alena Myslivcova Fucikova, Lenka Zidkova, Valeria Sheshko, Helena Rehulkova, Jiri Dresler and Zuzana Krocova

Toxins 2019, 11(3), 177; https://doi.org/10.3390/toxins11030177 - 23 Mar 2019

Cited by 10 | Viewed by 4968

Abstract

Targeted proteomics recently proved to be a technique for the detection and absolute quantification of proteins not easily accessible to classical bottom-up approaches. Due to this, it has been considered as a high fidelity tool to detect potential warfare agents in wide spread [...] Read more.

Targeted proteomics recently proved to be a technique for the detection and absolute quantification of proteins not easily accessible to classical bottom-up approaches. Due to this, it has been considered as a high fidelity tool to detect potential warfare agents in wide spread kinds of biological and environmental matrices. Clostridium perfringens toxins are considered to be potential biological weapons, especially the epsilon toxin which belongs to a group of the most powerful bacterial toxins. Here, the development of a target mass spectrometry method for the detection of C. perfringens protein toxins (alpha, beta, beta2, epsilon, iota) is described. A high-resolution mass spectrometer with a quadrupole-Orbitrap system operating in target acquisition mode (parallel reaction monitoring) was utilized. Because of the lack of commercial protein toxin standards recombinant toxins were prepared within Escherichia coli. The analysis was performed using proteotypic peptides as the target compounds together with their isotopically labeled synthetic analogues as internal standards. Calibration curves were calculated for each peptide in concentrations ranging from 0.635 to 1101 fmol/μL. Limits of detection and quantification were determined for each peptide in blank matrices. Full article

(This article belongs to the Collection Clostridium difficile/Clostridium sordellii and Clostridium perfringens Toxins)

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21 pages, 565 KiB

Open AccessEditor’s ChoiceReview

Harmful Effects and Control Strategies of Aflatoxin B₁ Produced by Aspergillus flavus and Aspergillus parasiticus Strains on Poultry: Review

by Ahmed Mohamed Fouad, Dong Ruan, HebatAllah Kasem El-Senousey, Wei Chen, Shouqun Jiang and Chuntian Zheng

Toxins 2019, 11(3), 176; https://doi.org/10.3390/toxins11030176 - 23 Mar 2019

Cited by 136 | Viewed by 10030

Abstract

The presence of aflatoxin B₁ (AFB₁) in poultry diets decreases the hatchability, hatchling weight, growth rate, meat and egg production, meat and egg quality, vaccination efficiency, as well as impairing the feed conversion ratio and increasing the susceptibility of birds [...] Read more.

The presence of aflatoxin B₁ (AFB₁) in poultry diets decreases the hatchability, hatchling weight, growth rate, meat and egg production, meat and egg quality, vaccination efficiency, as well as impairing the feed conversion ratio and increasing the susceptibility of birds to disease and mortality. AFB₁ is transferred from poultry feed to eggs, meat, and other edible parts, representing a threat to the health of consumers because AFB₁ is carcinogenic and implicated in human liver cancer. This review considers how AFB₁ produced by Aspergillus flavus and Aspergillus parasiticus strains can affect the immune system, antioxidant defense system, digestive system, and reproductive system in poultry, as well as its effects on productivity and reproductive performance. Nutritional factors can offset the effects of AFB₁ in poultry and, thus, it is necessary to identify and select suitable additives to address the problems caused by AFB₁ in poultry. Full article

(This article belongs to the Special Issue Fungal Infestations in Humans, Animals, Crops)

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20 pages, 741 KiB

Open AccessEditor’s ChoiceReview

FGF23, Biomarker or Target?

by Cristian Rodelo-Haad, Rafael Santamaria, Juan R. Muñoz-Castañeda, M. Victoria Pendón-Ruiz de Mier, Alejandro Martin-Malo and Mariano Rodriguez

Toxins 2019, 11(3), 175; https://doi.org/10.3390/toxins11030175 - 22 Mar 2019

Cited by 44 | Viewed by 10613

Abstract

Fibroblast growth factor 23 (FGF23) plays a key role in the complex network between the bones and other organs. Initially, it was thought that FGF23 exclusively regulated phosphate and vitamin D metabolism; however, recent research has demonstrated that an excess of FGF23 has [...] Read more.

Fibroblast growth factor 23 (FGF23) plays a key role in the complex network between the bones and other organs. Initially, it was thought that FGF23 exclusively regulated phosphate and vitamin D metabolism; however, recent research has demonstrated that an excess of FGF23 has other effects that may be detrimental in some cases. The understanding of the signaling pathways through which FGF23 acts in different organs is crucial to develop strategies aiming to prevent the negative effects associated with high FGF23 levels. FGF23 has been described to have effects on the heart, promoting left ventricular hypertrophy (LVH); the liver, leading to production of inflammatory cytokines; the bones, inhibiting mineralization; and the bone marrow, by reducing the production of erythropoietin (EPO). The identification of FGF23 receptors will play a remarkable role in future research since its selective blockade might reduce the adverse effects of FGF23. Patients with chronic kidney disease (CKD) have very high levels of FGF23 and may be the population suffering from the most adverse FGF23-related effects. The general population, as well as kidney transplant recipients, may also be affected by high FGF23. Whether the association between FGF23 and clinical events is causal or casual remains controversial. The hypothesis that FGF23 could be considered a therapeutic target is gaining relevance and may become a promising field of investigation in the future. Full article

(This article belongs to the Special Issue Disposition of Uremic Toxins: The Challenges in Uremia)

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16 pages, 2505 KiB

Open AccessArticle

Whole-Cell Multiparameter Assay for Ricin and Abrin Activity-Based Digital Holographic Microscopy

by Efi Makdasi, Orly Laskar, Elad Milrot, Ofir Schuster, Shlomo Shmaya and Shmuel Yitzhaki

Toxins 2019, 11(3), 174; https://doi.org/10.3390/toxins11030174 - 22 Mar 2019

Cited by 12 | Viewed by 5112

Abstract

Ricin and abrin are ribosome-inactivating proteins leading to inhibition of protein synthesis and cell death. These toxins are considered some of the most potent and lethal toxins against which there is no available antidote. Digital holographic microscopy (DHM) is a time-lapse, label-free, and [...] Read more.

Ricin and abrin are ribosome-inactivating proteins leading to inhibition of protein synthesis and cell death. These toxins are considered some of the most potent and lethal toxins against which there is no available antidote. Digital holographic microscopy (DHM) is a time-lapse, label-free, and noninvasive imaging technique that can provide phase information on morphological features of cells. In this study, we employed DHM to evaluate the morphological changes of cell lines during ricin and abrin intoxication. We showed that the effect of these toxins is characterized by a decrease in cell confluence and changes in morphological parameters such as cell area, perimeter, irregularity, and roughness. In addition, changes in optical parameters such as phase-shift, optical thickness, and effective-calculated volume were observed. These effects were completely inhibited by specific neutralizing antibodies. An enhanced intoxication effect was observed for preadherent compared to adherent cells, as was detected in early morphology changes and confirmed by annexin V/propidium iodide (PI) apoptosis assay. Detection of the dynamic changes in cell morphology at initial stages of cell intoxication by DHM emphasizes the highly sensitive and rapid nature of this method, allowing the early detection of active toxins. Full article

(This article belongs to the Collection Toxic and Pharmacological Effect of Plant Toxins)

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13 pages, 1695 KiB

Open AccessArticle

Toxicity of Bacillus thuringiensis-Derived Pesticidal Proteins Cry1Ab and Cry1Ba against Asian Citrus Psyllid, Diaphorina citri (Hemiptera)

by Maria Teresa Fernandez-Luna, Pavan Kumar, David G. Hall, Ashaki D. Mitchell, Michael B. Blackburn and Bryony C. Bonning

Toxins 2019, 11(3), 173; https://doi.org/10.3390/toxins11030173 - 22 Mar 2019

Cited by 19 | Viewed by 5246

Abstract

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera), is an important pest of citriculture. The ACP vectors a bacterium that causes huanglongbing (HLB), a devastating and incurable disease of citrus. The bacterium Bacillus thuringiensis (Bt) produces multiple toxins with activity against a [...] Read more.

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera), is an important pest of citriculture. The ACP vectors a bacterium that causes huanglongbing (HLB), a devastating and incurable disease of citrus. The bacterium Bacillus thuringiensis (Bt) produces multiple toxins with activity against a diverse range of insects. In efforts to provide additional control methods for the ACP vector of HLB, we identified pesticidal proteins derived from Bt for toxicity against ACP. The trypsin proteolytic profiles of strain-derived toxins were characterized. Strain IBL-00200, one of six strains with toxins shown to have basal activity against ACP was selected for liquid chromatography-mass spectrometry (LC-MS/MS) identification of the individual Cry toxins expressed. Toxicity assays with individual toxins derived from IBL-00200 were then performed. The activated form of the Cry toxins Cry1Ab and Cry1Ba were toxic to ACP with LC₅₀ values of approximately 120 µg/mL. Disruption of the midgut epithelium was associated with the toxicity of both the IBL-00200-derived toxin mixture, and with Cry1Ba. With further optimization of the efficacy of Cry1Ab and Cry1Ba, these toxins may have practical utility against ACP. Bt toxins with activity against ACP may provide an additional tool for management of ACP and the associated HLB disease, thereby providing a more sustainable and environmentally benign approach than repeated application of broad-spectrum insecticides. Full article

(This article belongs to the Special Issue Insecticidal Toxins: Advances in Discovery and PestControl Applications)

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13 pages, 4878 KiB

Open AccessEditor’s ChoiceArticle

The Spodoptera exigua ABCC2 Acts as a Cry1A Receptor Independently of its Nucleotide Binding Domain II

by Daniel Pinos, María Martínez-Solís, Salvador Herrero, Juan Ferré and Patricia Hernández-Martínez

Toxins 2019, 11(3), 172; https://doi.org/10.3390/toxins11030172 - 22 Mar 2019

Cited by 18 | Viewed by 4775

Abstract

ABC proteins are primary-active transporters that require the binding and hydrolysis of ATP to transport substrates across the membrane. Since the first report of an ABCC2 transporter as receptor of Cry1A toxins, the number of ABC transporters known to be involved in the [...] Read more.

ABC proteins are primary-active transporters that require the binding and hydrolysis of ATP to transport substrates across the membrane. Since the first report of an ABCC2 transporter as receptor of Cry1A toxins, the number of ABC transporters known to be involved in the mode of action of Cry toxins has increased. In Spodoptera exigua, a mutation in the SeABCC2 gene is described as genetically linked to resistance to the Bt-product Xentari^TM. This mutation affects an intracellular domain involved in ATP binding, but not the extracellular loops. We analyzed whether this mutation affects the role of the SeABCC2 as a functional receptor to Cry1A toxins. The results show that Sf21 cells expressing the truncated form of the transporter were susceptible to Cry1A toxins. Moreover, specific Cry1Ac binding was observed in those cells expressing the truncated SeABCC2. Additionally, no differences in the irreversible Cry1Ac binding component (associated with the toxin insertion into the membrane) were observed when tested in Sf21 cells expressing either the full-length or the truncated form of the SeABCC2 transporter. Therefore, our results point out that the partial lack of the nucleotide binding domain II in the truncated transporter does not affect its functionality as a Cry1A receptor. Full article

(This article belongs to the Special Issue Insecticidal Toxins from Bacillus thuringiensis)

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30 pages, 4336 KiB

Open AccessEditor’s ChoiceArticle

Multi LC-MS/MS and LC-HRMS Methods for Determination of 24 Mycotoxins including Major Phase I and II Biomarker Metabolites in Biological Matrices from Pigs and Broiler Chickens

by Marianne Lauwers, Siegrid De Baere, Ben Letor, Michael Rychlik, Siska Croubels and Mathias Devreese

Toxins 2019, 11(3), 171; https://doi.org/10.3390/toxins11030171 - 19 Mar 2019

Cited by 55 | Viewed by 6912

Abstract

A reliable and practical multi-method was developed for the quantification of mycotoxins in plasma, urine, and feces of pigs, and plasma and excreta of broiler chickens using liquid chromatography–tandem mass spectrometry. The targeted mycotoxins belong to the regulated groups, i.e., aflatoxins, ochratoxin A [...] Read more.

A reliable and practical multi-method was developed for the quantification of mycotoxins in plasma, urine, and feces of pigs, and plasma and excreta of broiler chickens using liquid chromatography–tandem mass spectrometry. The targeted mycotoxins belong to the regulated groups, i.e., aflatoxins, ochratoxin A and Fusarium mycotoxins, and to two groups of emerging mycotoxins, i.e., Alternaria mycotoxins and enniatins. In addition, the developed method was transferred to a LC-high resolution mass spectrometry instrument to qualitatively determine phase I and II metabolites, for which analytical standards are not always commercially available. Sample preparation of plasma was simple and generic and was accomplished by precipitation of proteins alone (pig) or in combination with removal of phospholipids (chicken). A more intensive sample clean-up of the other matrices was needed and consisted of a pH-dependent liquid–liquid extraction (LLE) using ethyl acetate (pig urine), methanol/ethyl acetate/formic acid (75/24/1, v/v/v) (pig feces) or acetonitrile (chicken excreta). For the extraction of pig feces, additionally a combination of LLE using acetone and filtration of the supernatant on a HybridSPE-phospholipid cartridge was applied. The LC-MS/MS method was in-house validated according to guidelines defined by the European and international community. Finally, the multi-methods were successfully applied in a specific toxicokinetic study and a screening study to monitor the exposure of individual animals. Full article

(This article belongs to the Special Issue Application of LC-MS/MS in the Mycotoxins Studies)

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23 pages, 9587 KiB

Open AccessArticle

Protease Activity Profiling of Snake Venoms Using High-Throughput Peptide Screening

by Konstantinos Kalogeropoulos, Andreas Frederik Treschow, Ulrich auf dem Keller, Teresa Escalante, Alexandra Rucavado, José María Gutiérrez, Andreas Hougaard Laustsen and Christopher T. Workman

Toxins 2019, 11(3), 170; https://doi.org/10.3390/toxins11030170 - 19 Mar 2019

Cited by 13 | Viewed by 6168

Abstract

Snake venom metalloproteinases (SVMPs) and snake venom serine proteinases (SVSPs) are among the most abundant enzymes in many snake venoms, particularly among viperids. These proteinases are responsible for some of the clinical manifestations classically seen in viperid envenomings, including hemorrhage, necrosis, and coagulopathies. [...] Read more.

Snake venom metalloproteinases (SVMPs) and snake venom serine proteinases (SVSPs) are among the most abundant enzymes in many snake venoms, particularly among viperids. These proteinases are responsible for some of the clinical manifestations classically seen in viperid envenomings, including hemorrhage, necrosis, and coagulopathies. The objective of this study was to investigate the enzymatic activities of these proteins using a high-throughput peptide library to screen for the proteinase targets of the venoms of five viperid (Echis carinatus, Bothrops asper, Daboia russelii, Bitis arietans, Bitis gabonica) and one elapid (Naja nigricollis) species of high medical importance. The proteinase activities of these venoms were each tested against 360 peptide substrates, yielding 2160 activity profiles. A nonlinear regression model that accurately described the observed enzymatic activities was fitted to the experimental data, allowing for the comparison of cleavage rates across species. In this study, previously unknown protein targets of snake venom proteinases were identified, potentially implicating novel human and animal proteins that may be involved in the pathophysiology of viper envenomings. The functional relevance of these targets was further evaluated and discussed. These new findings may contribute to our understanding of the clinical manifestations and underlying biochemical mechanisms of snakebite envenoming by viperid species. Full article

(This article belongs to the Section Animal Venoms)

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8 pages, 1262 KiB

Open AccessArticle

Bioaccumulation and Distribution of Indospicine and Its Foregut Metabolites in Camels Fed Indigofera spicata

by Gabriele Netzel, Eddie T. T. Tan, Mukan Yin, Cindy Giles, Ken W. L. Yong, Rafat Al Jassim and Mary T. Fletcher

Toxins 2019, 11(3), 169; https://doi.org/10.3390/toxins11030169 - 19 Mar 2019

Cited by 4 | Viewed by 2963

Abstract

In vitro experiments have demonstrated that camel foregut-fluid has the capacity to metabolize indospicine, a natural toxin which causes hepatotoxicosis, but such metabolism is in competition with absorption and outflow of indospicine from the different segments of the digestive system. Six young camels [...] Read more.

In vitro experiments have demonstrated that camel foregut-fluid has the capacity to metabolize indospicine, a natural toxin which causes hepatotoxicosis, but such metabolism is in competition with absorption and outflow of indospicine from the different segments of the digestive system. Six young camels were fed Indigofera spicata (337 µg indospicine/kg BW/day) for 32 days, at which time three camels were euthanized. The remaining camels were monitored for a further 100 days after cessation of this indospicine diet. In a retrospective investigation, relative levels of indospicine foregut-metabolism products were examined by UHPLC-MS/MS in plasma, collected during both accumulation and depletion stages of this experiment. The metabolite 2-aminopimelamic acid could be detected at low levels in almost all plasma samples, whereas 2-aminopimelic acid could not be detected. In the euthanized camels, 2-aminopimelamic acid could be found in all tissues except muscle, whereas 2-aminopimelic acid was only found in the kidney, pancreas, and liver tissues. The clearance rate for these metabolites was considerably greater than for indospicine, which was still present in plasma of the remaining camels 100 days after cessation of Indigofera consumption. Full article

(This article belongs to the Special Issue Food Safety and Natural Toxins)

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14 pages, 1264 KiB

Open AccessArticle

Daboia (Vipera) palaestinae Envenomation in 123 Horses: Treatment and Efficacy of Antivenom Administration

by Sharon Tirosh-Levy, Reut Solomovich-Manor, Judith Comte, Israel Nissan, Gila A. Sutton, Annie Gabay, Emanuel Gazit and Amir Steinman

Toxins 2019, 11(3), 168; https://doi.org/10.3390/toxins11030168 - 19 Mar 2019

Cited by 6 | Viewed by 4674

Abstract

Envenomation by venomous snakes is life threatening for horses. However, the efficacy of available treatments for this occurrence, in horses, has not yet been adequately determined. The aim of this study was to describe the treatments provided in cases of Daboia palaestinae envenomation [...] Read more.

Envenomation by venomous snakes is life threatening for horses. However, the efficacy of available treatments for this occurrence, in horses, has not yet been adequately determined. The aim of this study was to describe the treatments provided in cases of Daboia palaestinae envenomation in horses and to evaluate the safety and efficacy of antivenom administration. Data regarding 123 equine snakebite cases were collected over four years from 25 veterinarians. The majority of horses were treated with procaine-penicillin (92.7%), non-steroidal anti-inflammatory drugs (82.3%), dexamethasone (81.4%), tetanus toxoid (91.1%) and antivenom (65.3%). The time interval between treatment and either cessation or 50% reduction of local swelling was linearly associated with case fatality (p < 0.001). The overall mortality rate was 20.3%. Treatment with procaine-penicillin was significantly associated with reduced mortality (OR = 0.11). Three horse-derived antivenom products were available during the study period, of which the horses were administered different brands of varying dosages. Administration of the recommended dosage of any of the aforementioned products led to a significant decrease in mortality (p = 0.014), even in severe cases (scoring 2 or greater on the equine snakebite severity scale). No adverse reactions were reported. The results of this study show that species-specific D. palaestinae antivenom administered at the manufacturer-recommended dosage is effective in significantly reducing mortality in cases of envenomation in horses. Full article

(This article belongs to the Section Animal Venoms)

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37 pages, 7260 KiB

Open AccessEditor’s ChoiceArticle

The Dual Prey-Inactivation Strategy of Spiders—In-Depth Venomic Analysis of Cupiennius salei

by Lucia Kuhn-Nentwig, Nicolas Langenegger, Manfred Heller, Dominique Koua and Wolfgang Nentwig

Toxins 2019, 11(3), 167; https://doi.org/10.3390/toxins11030167 - 19 Mar 2019

Cited by 36 | Viewed by 9968

Abstract

Most knowledge of spider venom concerns neurotoxins acting on ion channels, whereas proteins and their significance for the envenomation process are neglected. The here presented comprehensive analysis of the venom gland transcriptome and proteome of Cupiennius salei focusses on proteins and cysteine-containing peptides [...] Read more.

Most knowledge of spider venom concerns neurotoxins acting on ion channels, whereas proteins and their significance for the envenomation process are neglected. The here presented comprehensive analysis of the venom gland transcriptome and proteome of Cupiennius salei focusses on proteins and cysteine-containing peptides and offers new insight into the structure and function of spider venom, here described as the dual prey-inactivation strategy. After venom injection, many enzymes and proteins, dominated by α-amylase, angiotensin-converting enzyme, and cysteine-rich secretory proteins, interact with main metabolic pathways, leading to a major disturbance of the cellular homeostasis. Hyaluronidase and cytolytic peptides destroy tissue and membranes, thus supporting the spread of other venom compounds. We detected 81 transcripts of neurotoxins from 13 peptide families, whereof two families comprise 93.7% of all cysteine-containing peptides. This raises the question of the importance of the other low-expressed peptide families. The identification of a venom gland-specific defensin-like peptide and an aga-toxin-like peptide in the hemocytes offers an important clue on the recruitment and neofunctionalization of body proteins and peptides as the origin of toxins. Full article

(This article belongs to the Section Animal Venoms)

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16 pages, 1814 KiB

Open AccessEditor’s ChoiceArticle

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

by Danlei Sun, Nannan Qiu, Shuang Zhou, Bing Lyu, Shuo Zhang, Jingguang Li, Yunfeng Zhao and Yongning Wu

Toxins 2019, 11(3), 166; https://doi.org/10.3390/toxins11030166 - 17 Mar 2019

Cited by 23 | Viewed by 4511

Abstract

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 [...] Read more.

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

(This article belongs to the Special Issue 2^nd MycoKey International Conference - Integrated Solutions for Mycotoxin Management)

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18 pages, 305 KiB

Open AccessEditor’s ChoiceArticle

Variation of Fungal Metabolites in Sorghum Malts Used to Prepare Namibian Traditional Fermented Beverages Omalodu and Otombo

by Sylvia N. Nafuka, Jane M. Misihairabgwi, Ronnie Bock, Anthony Ishola, Michael Sulyok and Rudolf Krska

Toxins 2019, 11(3), 165; https://doi.org/10.3390/toxins11030165 - 16 Mar 2019

Cited by 18 | Viewed by 4262

Abstract

Sorghum malts, which are important ingredients in traditional fermented beverages, are commonly infected by mycotoxigenic fungi and mycotoxins may transfer into the beverages, risking consumers’ health. Liquid chromatography–tandem mass spectrometry was used to determine variation of fungal metabolites in 81 sorghum malts processed [...] Read more.

Sorghum malts, which are important ingredients in traditional fermented beverages, are commonly infected by mycotoxigenic fungi and mycotoxins may transfer into the beverages, risking consumers’ health. Liquid chromatography–tandem mass spectrometry was used to determine variation of fungal metabolites in 81 sorghum malts processed for brewing of Namibian beverages, otombo (n = 45) and omalodu (n = 36). Co-occurrence of European Union (EU)-regulated mycotoxins, such as patulin, aflatoxins (B₁, B₂, and G₂), and fumonisins (B₁, B₂, and B₃) was detected in both malts with a prevalence range of 2–84%. Aflatoxin B₁ was quantified in omalodu (44%) and otombo malts (14%), with 20% of omalodu malts and 40% of otombo malts having levels above the EU allowable limit. Fumonisin B₁ was quantified in both omalodu (84%) and otombo (42%) malts. Emerging mycotoxins, aflatoxin precursors, and ergot alkaloids were quantified in both malts. Notably, 102 metabolites were quantified in both malts, with 96% in omalodu malts and 93% in otombo malts. An average of 48 metabolites were quantified in otombo malts while an average of 67 metabolites were quantified in omalodu malts. The study accentuates the need to monitor mycotoxins in sorghum malts intended for brewing and to determine their fate in the beverages. Full article

(This article belongs to the Special Issue Application of LC-MS/MS in the Mycotoxins Studies)

8 pages, 1724 KiB

Open AccessEditor’s ChoiceArticle

Regulation of Microcystin-LR-Induced DNA Damage by miR-451a in HL7702 Cells

by Lv Chen, Shu Yang, Cong Wen, Shuilin Zheng, Yue Yang, Xiangling Feng, Jihua Chen, Dan Luo, Ran Liu and Fei Yang

Toxins 2019, 11(3), 164; https://doi.org/10.3390/toxins11030164 - 15 Mar 2019

Cited by 26 | Viewed by 3614

Abstract

Microcystin-LR is a cyclic heptapeptide hepatotoxin produced by harmful cyanobacteria. A panel of microRNAs containing miR-451a were found to be significantly changed in normal human liver cells HL7702 after exposure to microcystin-LR (MC-LR) in our previous study. However, the functions of miR-451a in [...] Read more.

Microcystin-LR is a cyclic heptapeptide hepatotoxin produced by harmful cyanobacteria. A panel of microRNAs containing miR-451a were found to be significantly changed in normal human liver cells HL7702 after exposure to microcystin-LR (MC-LR) in our previous study. However, the functions of miR-451a in hepatotoxicity induced by MC-LR remained unclear. The study aimed to investigate the impacts of miR-451a in HL7702 cells following treatment with 5 or 10 μM MC-LR. The comet assay indicated that MC-LR can influence Olive tail moment (OTM) in HL7702 cells. Furthermore, increase of miR-451a significantly repressed DNA damage and the protein expression level of γ-H2AX induced by MC-LR. Moreover, over-expression of miR-451a inhibited the expression level of p-AKT1 protein in cells following treatment by MC-LR. These results showed that miR-451a may protect from MC-LR-induced DNA damage by down-regulating the expression of p-AKT1, which provides new clues for the diagnosis and therapy policies for liver damage induced by MC-LR. Full article

(This article belongs to the Collection Toxicological Challenges of Aquatic Toxins)

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17 pages, 1286 KiB

Open AccessEditor’s ChoiceArticle

Study on Trichothecene and Zearalenone Presence in Romanian Wheat Relative to Weather Conditions

by Oana Stanciu, Cristina Juan, Houda Berrada, Doina Miere, Felicia Loghin and Jordi Mañes

Toxins 2019, 11(3), 163; https://doi.org/10.3390/toxins11030163 - 15 Mar 2019

Cited by 36 | Viewed by 4305

Abstract

To evaluate the influence of weather conditions on mycotoxin presence in wheat, deoxynivalenol (DON), 3-acetyldeoxynivalenol (3AcDON), 15-acetyldeoxynivalenol (15AcDON), fusarenon-X (FUS-X), nivalenol (NIV), HT-2 toxin (HT-2), T-2 toxin (T-2), diacetoxyscirpenol (DAS), neosolaniol (NEO) and zearalenone (ZEN) were evaluated in 102 Romanian wheat samples coming [...] Read more.

To evaluate the influence of weather conditions on mycotoxin presence in wheat, deoxynivalenol (DON), 3-acetyldeoxynivalenol (3AcDON), 15-acetyldeoxynivalenol (15AcDON), fusarenon-X (FUS-X), nivalenol (NIV), HT-2 toxin (HT-2), T-2 toxin (T-2), diacetoxyscirpenol (DAS), neosolaniol (NEO) and zearalenone (ZEN) were evaluated in 102 Romanian wheat samples coming from five wheat growing areas during 2015. Only six mycotoxins were detected, while FUS-X, DAS, NEO and NIV were not present in the wheat samples. Mycotoxin concentrations were correlated with precipitation and temperature values during anthesis and the preharvest period. Overall, the highest frequency was registered for DON, while the lowest frequency was registered for NIV. In the North Muntenia, DON and ZEN registered high frequencies (68% and 16%, respectively). This region was characterized in June and July by medium to high values of rainfall (41–100 mm/month) and normal temperatures (mean of 20.0 °C in June and 24.0 °C in July), suggesting that precipitation levels influence fungi and mycotoxin development to a greater extent compared to the influence of temperature. Full article

(This article belongs to the Collection Understanding Mycotoxin Occurrence in Food and Feed Chains)

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18 pages, 2882 KiB

Open AccessArticle

Engineering of Bacillus thuringiensis Cry Proteins to Enhance the Activity against Western Corn Rootworm

by Jingtong Hou, Ruth Cong, Michi Izumi-Willcoxon, Hana Ali, Yi Zheng, Ericka Bermudez, Mark McDonald, Mark Nelson and Takashi Yamamoto

Toxins 2019, 11(3), 162; https://doi.org/10.3390/toxins11030162 - 14 Mar 2019

Cited by 14 | Viewed by 4488

Abstract

A novel Bacillus thuringiensis Cry protein, Cry8Hb, active against Diabrotica virgifera virgifera (Western corn rootworm, WCRW) was discovered. Unexpectedly, the anti-rootworm activity of the Cry8Hb toxin was enhanced significantly by fusing Escherichia coli maltose binding protein (MBP) to this Cry toxin. While the [...] Read more.

A novel Bacillus thuringiensis Cry protein, Cry8Hb, active against Diabrotica virgifera virgifera (Western corn rootworm, WCRW) was discovered. Unexpectedly, the anti-rootworm activity of the Cry8Hb toxin was enhanced significantly by fusing Escherichia coli maltose binding protein (MBP) to this Cry toxin. While the exact mechanism of the activity enhancement remains indefinite, it is probable that the enhancement is a result of increased solubility of the MBP-Cry8Hb fusion in the rootworm midgut. This hypothesis was examined using a synthetic Cry3 protein called IP3-1, which was not soluble at a neutral pH like Cry8Hb and marginally active to WCRW. When IP3-1 was fused to MBP, its anti-WCRW activity was enhanced 13-fold. To further test the hypothesis, DNA shuffling was performed on IP3-1 to increase the solubility without MBP. Screening of shuffled libraries found six new IP3 variants showing very high anti-WCRW activity without MBP. Sequence and 3D structure analysis of those highly active, shuffled IP3 variants revealed several charge-altering mutations such as Lys to Glu on the putative MBP-attaching side of the IP3 molecule. It is likely that those mutations make the protein acidic to substitute the functions of MBP including enhancing the solubility of IP3 at a neutral pH. Full article

(This article belongs to the Special Issue Insecticidal Toxins from Bacillus thuringiensis)

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10 pages, 600 KiB

Open AccessEditor’s ChoiceArticle

Efficacy of Bacillus subtilis ANSB060 Biodegradation Product for the Reduction of the Milk Aflatoxin M₁ Content of Dairy Cows Exposed to Aflatoxin B₁

by Yongpeng Guo, Yong Zhang, Chen Wei, Qiugang Ma, Cheng Ji, Jianyun Zhang and Lihong Zhao

Toxins 2019, 11(3), 161; https://doi.org/10.3390/toxins11030161 - 13 Mar 2019

Cited by 16 | Viewed by 3671

Abstract

This study was conducted to determine the effect of Bacillus subtilis ANSB060 biodegradation product (BDP) in reducing the milk aflatoxin M₁ (AFM₁) content of dairy cows fed a diet contaminated with aflatoxin B₁ (AFB₁). Twenty-four Chinese Holstein [...] Read more.

This study was conducted to determine the effect of Bacillus subtilis ANSB060 biodegradation product (BDP) in reducing the milk aflatoxin M₁ (AFM₁) content of dairy cows fed a diet contaminated with aflatoxin B₁ (AFB₁). Twenty-four Chinese Holstein cows (254 ± 19 d in milk; milk production 19.0 ± 1.2 kg d⁻¹) were assigned to three dietary treatments, as follows: (1) control diet (CON), consisting of a basal total mixed ration (TMR); (2) aflatoxin diet (AF), containing CON plus 63 μg of AFB₁ kg⁻¹ of diet dry matter; and (3) aflatoxin diet plus BDP (AF + BDP), containing AF plus BDP at 0.2% of diet dry matter. The experiment lasted 12 days, including an AFB₁-dosing period from days one to eight, followed by a clearance period from days nine to twelve. Milk samples were collected on days 2, 4, 6, and 8–12, and the plasma was sampled on day 9, before morning feeding. Short-term AFB₁ exposure did not affect the milk production and composition. The plasma biochemical indices, except for lactic dehydrogenase (LDH), were also not changed by the AFB₁ intake. The plasma LDH level was significantly elevated (p < 0.05) following dietary treatment with AFB₁, while no significant difference was observed between the AF + BDP and CON treatments. Adding BDP to the AFB₁-contaminaed diet resulted in a significant reduction in AFM₁ concentration (483 vs. 665 ng L⁻¹) in the milk, AFM₁ excretion (9.14 vs. 12.71 μg d⁻¹), and transfer rate of dietary AFB₁ to milk AFM₁ (0.76 vs. 1.06%). In conclusion, the addition of BDP could be an alternative method for reducing the dietary AFB₁ bioavailability in dairy cows. Full article

(This article belongs to the Section Mycotoxins)

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9 pages, 403 KiB

Open AccessEditor’s ChoiceArticle

Natural Occurrence and Co-Contamination of Twelve Mycotoxins in Industry-Submitted Cool-Season Cereal Grains Grown under a Low Heat Unit Climate Condition

by Haitao Shi, Warren Schwab and Peiqiang Yu

Toxins 2019, 11(3), 160; https://doi.org/10.3390/toxins11030160 - 13 Mar 2019

Cited by 26 | Viewed by 3786

Abstract

This study aims to evaluate the prevalence of mycotoxins in industry-submitted cool-season barley and wheat grown under low heat unit climate conditions. Seventy-two barley samples and 83 wheat samples were submitted by producers and industry from May 2016 to May 2017. The concentrations [...] Read more.

This study aims to evaluate the prevalence of mycotoxins in industry-submitted cool-season barley and wheat grown under low heat unit climate conditions. Seventy-two barley samples and 83 wheat samples were submitted by producers and industry from May 2016 to May 2017. The concentrations of twelve common mycotoxins, including nivalenol (NIV), deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON), ochratoxin A (OTA), zearalenone (ZEN), α-zearalenol (α-ZAL), β-zearalenol (β-ZAL), diacetoxyscirpenol (DAS), T-2 toxin (T-2), HT-2 toxin (HT-2), and aflatoxin B1 (AFB1), were determined using the liquid chromatography/tandem mass spectrometry method. Mycotoxins were detected in 40 barley (56%) and 35 wheat (42%) samples submitted by producers and industry. DON showed the highest incidence in barley (44%) and wheat (33%). None of the barley samples contained detectable DAS and no wheat samples tested positive for α-ZAL, DAS, T-2, or AFB1. Co-occurrence of DON and other mycotoxins was frequently observed. Among the mycotoxin-positive samples, 70% of barley samples and 54% of wheat samples were co-contaminated with at least two mycotoxins. Four barley (6%) and five wheat (6%) samples contained levels of DON above 1000 μg/kg (regulatory level in diets for lactating dairy animals) and HT-2 content in five barley (7%) and four wheat (5%) samples exceeded 100 μg/kg (regulatory level in diets for cattle and poultry). Overall, contamination of these mycotoxins was more frequent and more severe in barley in comparison with wheat that was submitted by producers and industry. Comprehensive strategies, including the prevention of Fusarium toxins contamination, the routine monitoring of their prevalence, the detoxification of them in feed and food, as well as the inhibition of their absorption in the gastrointestinal tract, are highly required. A rapid detection method needs to be developed to screen mycotoxins in industry-submitted cool-season cereal grains. Full article

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3 pages, 199 KiB

Open AccessEditorial

Effects of Mycotoxins on the Intestine

by Imourana Alassane-Kpembi, Philippe Pinton and Isabelle P. Oswald

Toxins 2019, 11(3), 159; https://doi.org/10.3390/toxins11030159 - 13 Mar 2019

Cited by 24 | Viewed by 4956

Abstract

The gastrointestinal tract is the first physiological barrier against food contaminants, as well as the first target for these toxicants [...] Full article

(This article belongs to the Special Issue Effects of Mycotoxins on the Intestine)

13 pages, 2226 KiB

Open AccessArticle

Multiple CH/π Interactions Maintain the Binding of Aflatoxin B₁ in the Active Cavity of Human Cytochrome P450 1A2

by Jun Wu, Sisi Zhu, Yunbo Wu, Tianqing Jiang, Lingling Wang, Jun Jiang, Jikai Wen and Yiqun Deng

Toxins 2019, 11(3), 158; https://doi.org/10.3390/toxins11030158 - 12 Mar 2019

Cited by 9 | Viewed by 3329

Abstract

Human cytochrome P450 1A2 (CYP1A2) is one of the key CYPs that activate aflatoxin B₁ (AFB₁), a notorious mycotoxin, into carcinogenic exo-8,9-epoxides (AFBO) in the liver. Although the structure of CYP1A2 is available, the mechanism of CYP1A2-specific binding to AFB [...] Read more.

Human cytochrome P450 1A2 (CYP1A2) is one of the key CYPs that activate aflatoxin B₁ (AFB₁), a notorious mycotoxin, into carcinogenic exo-8,9-epoxides (AFBO) in the liver. Although the structure of CYP1A2 is available, the mechanism of CYP1A2-specific binding to AFB₁ has not been fully clarified. In this study, we used calculation biology to predict a model of CYP1A2 with AFB₁, where Thr-124, Phe-125, Phe-226, and Phe-260 possibly participate in the specific binding. Site-directed mutagenesis was performed to construct mutants T124A, F125A, F226A, and F260A. Escherichia coli-expressed recombinant proteins T124A, F226A, and F260A had active structures, while F125A did not. This was evidenced by Fe²⁺∙Carbon monoxide (CO)-reduced difference spectra and circular dichroism spectroscopy. Mutant F125A was expressed in HEK293T cells. Steady kinetic assays showed that T124A had enhanced activity towards AFB₁, while F125A, F226A, and F260A were significantly reduced in their ability to activate AFB₁, implying that hydrogen bonds between Thr-124 and AFB₁ were not important for substrate-specific binding, whereas Phe-125, Phe-226, and Phe-260 were essential for the process. The computation simulation and experimental results showed that the three key CH/π interactions between Phe-125, Phe-226, or Phe-260 and AFB₁ collectively maintained the stable binding of AFB₁ in the active cavity of CYP1A2. Full article

(This article belongs to the Collection Aflatoxins)

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13 pages, 3039 KiB

Open AccessEditor’s ChoiceArticle

Proanthocyanidins Alleviates AflatoxinB₁-Induced Oxidative Stress and Apoptosis through Mitochondrial Pathway in the Bursa of Fabricius of Broilers

by Shahid Ali Rajput, Cong Zhang, Yue Feng, Xiao Tian Wei, Mahmoud Mohamed Khalil, Imran Rashid Rajput, Dost Muhammad Baloch, Aftab Shaukat, Nasir Rajput, Hammad Qamar, Mubashar Hassan and Desheng Qi

Toxins 2019, 11(3), 157; https://doi.org/10.3390/toxins11030157 - 10 Mar 2019

Cited by 49 | Viewed by 4594

Abstract

Aflatoxin B₁ (AFB₁) is a serious threat to the poultry industry. Proanthocyanidins (PCs) demonstrates a broad range of biological, pharmacological, therapeutic, and chemoprotective properties. The aim of this study was to investigate the ameliorative effects of PCs against AFB₁ [...] Read more.

Aflatoxin B₁ (AFB₁) is a serious threat to the poultry industry. Proanthocyanidins (PCs) demonstrates a broad range of biological, pharmacological, therapeutic, and chemoprotective properties. The aim of this study was to investigate the ameliorative effects of PCs against AFB₁-induced histopathology, oxidative stress, and apoptosis via the mitochondrial pathway in the bursa of Fabricius (BF) of broilers. One hundred forty-four one-day old Cobb chicks were randomly assigned into four treatment groups of six replicates (6 birds each replicate) for 28 days. Groups were fed on the following four diets; (1) Basal diet without addition of PCs or AFB₁ (Control); (2) basal diet supplemented with 1 mg/kg AFB₁ from contaminated corn (AFB₁); (3) basal diet supplemented with 250 mg/kg PCs (PCs); and (4) basal diet supplemented with 1 mg/kg AFB₁ + 250 mg/kg PCs (AFB₁+ PCs). The present study results showed that antioxidant enzymes activities of total superoxide dismutase (T-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione S-transferase (GST) in AFB₁ treated group were (p < 0.05) decreased, whereas malondialdehyde (MDA) contents were significantly increased in comparison with the control group. Furthermore, we found that dietary PCs treatment ameliorated AFB₁-induced oxidative stress in the BF through inhibiting the accumulation of MDA content and enhancing the antioxidant enzymes activities (T-SOD, CAT, GSH-Px, and GST). Similarly, PCs markedly enhanced messenger RNA (mRNA) expression of antioxidant genes (SOD, CAT, GPx1, and GST) in comparison with AFB₁ group. Moreover, histological results showed that PCs alleviated AFB₁-induced apoptotic cells in the BF of broilers. In addition, both mRNA and protein expression results manifested that mitochondrial-apoptosis-associated genes (Bax, caspase-9, caspase-3, and p53 and cytochrome c) showed up-regulation, while (Bcl-2) showed down-regulation in AFB₁ fed group. The supplementation of PCs to AFB₁ diet significantly reversed the mRNA and protein expression of these apoptosis-associated genes, as compared to the AFB₁ group. Our results demonstrated that PCs ameliorated AFB₁-induced oxidative stress by modulating the antioxidant defense system and apoptosis in the BF through mitochondrial pathway in broilers. Full article

(This article belongs to the Special Issue Mycotoxins, Immunity, and Inflammation)

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12 pages, 1462 KiB

Open AccessArticle

Inhibitory Effect of Metalloproteinase Inhibitors on Skin Cell Inflammation Induced by Jellyfish Nemopilema nomurai Nematocyst Venom

by Aoyu Li, Huahua Yu, Rongfeng Li, Song Liu, Ronge Xing and Pengcheng Li

Toxins 2019, 11(3), 156; https://doi.org/10.3390/toxins11030156 - 10 Mar 2019

Cited by 20 | Viewed by 4162

Abstract

Jellyfish envenomations result in extensive dermatological symptoms, clinically named as jellyfish dermatitis, which can seriously affect the daily activities and physical health of people. Inflammatory response accompanies the whole process of jellyfish dermatitis and the complexity of jellyfish venom components makes it difficult [...] Read more.

Jellyfish envenomations result in extensive dermatological symptoms, clinically named as jellyfish dermatitis, which can seriously affect the daily activities and physical health of people. Inflammatory response accompanies the whole process of jellyfish dermatitis and the complexity of jellyfish venom components makes it difficult to treat jellyfish dermatitis symptoms effectively. Moreover, inhibiting inflammation is essential for the treatment of jellyfish stings and exploring the main components of jellyfish venom that cause inflammation is an urgent research area. In this study, the inhibitory effects of matrix metalloproteinase (MMP) inhibitors for venom-induced inflammation were explored at a cellular level. The expression of the three inflammatory factors, IL-6, TNF-α and MCP-1 in two skin cell lines, human keratinocyte cells (HaCaT) and human embryonic skin fibroblasts cells (CCC-ESF-1), at the cellular level, after treatment with the inhibitors of jellyfish Nemopilema nomurai (N. nomurai) nematocyst venom (NnNV-I), were determined. The results showed that inhibitors of MMP can significantly reduce the toxic effects of jellyfish Nemopilema nomurai nematocyst venom (NnNV) to skin cells. The expression levels of the three inflammatory factors IL-6, MCP-1, and TNF-α in the cells were also significantly decreased, indicating that MMPs in jellyfish venom are probably vital factors leading to jellyfish dermatitis. This study is beneficial in the prevention and treatment of jellyfish stings. Full article

(This article belongs to the Collection Toxicological Challenges of Aquatic Toxins)

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15 pages, 1694 KiB

Open AccessArticle

New Mastoparan Peptides in the Venom of the Solitary Eumenine Wasp Eumenes micado

by Katsuhiro Konno, Kohei Kazuma, Marisa Rangel, Joacir Stolarz-de-Oliveira, Renato Fontana, Marii Kawano, Hiroyuki Fuchino, Izumi Hide, Tadashi Yasuhara and Yoshihiro Nakata

Toxins 2019, 11(3), 155; https://doi.org/10.3390/toxins11030155 - 10 Mar 2019

Cited by 19 | Viewed by 4119

Abstract

Comprehensive LC-MS and MS/MS analysis of the crude venom extract from the solitary eumenine wasp Eumenes micado revealed the component profile of this venom mostly consisted of small peptides. The major peptide components, eumenine mastoparan-EM1 (EMP-EM1: LKLMGIVKKVLGAL-NH₂) and eumenine mastoparan-EM2 (EMP-EM2: [...] Read more.

Comprehensive LC-MS and MS/MS analysis of the crude venom extract from the solitary eumenine wasp Eumenes micado revealed the component profile of this venom mostly consisted of small peptides. The major peptide components, eumenine mastoparan-EM1 (EMP-EM1: LKLMGIVKKVLGAL-NH₂) and eumenine mastoparan-EM2 (EMP-EM2: LKLLGIVKKVLGAI-NH₂), were purified and characterized by the conventional method. The sequences of these new peptides are homologous to mastoparans, the mast cell degranulating peptides from social wasp venoms; they are 14 amino acid residues in length, rich in hydrophobic and basic amino acids, and C-terminal amidated. Accordingly, these new peptides can belong to mastoparan peptides (in other words, linear cationic α-helical peptides). Indeed, the CD spectra of these new peptides showed predominantly α-helix conformation in TFE and SDS. In biological evaluation, both peptides exhibited potent antibacterial activity, moderate degranulation activity from rat peritoneal mast cells, and significant leishmanicidal activity, while they showed virtually no hemolytic activity on human or mouse erythrocytes. These results indicated that EMP-EM peptides rather strongly associated with bacterial cell membranes rather than mammalian cell membranes. Full article

(This article belongs to the Special Issue Toxins-Membrane Interactions)

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14 pages, 1738 KiB

Open AccessEditor’s ChoiceArticle

Quercetin Inhibits the Proliferation and Aflatoxins Biosynthesis of Aspergillus flavus

by Xiu-Mei Li, Zhong-Yuan Li, Ya-Dong Wang, Jin-Quan Wang and Pei-Long Yang

Toxins 2019, 11(3), 154; https://doi.org/10.3390/toxins11030154 - 9 Mar 2019

Cited by 34 | Viewed by 4016

Abstract

In this work of quercetin’s anti-proliferation action on A. flavus, we revealed that quercetin can effectively hamper the proliferation of A. flavus in dose-effect and time-effect relationships. We tested whether quercetin induced apoptosis in A. flavus via various detection methods, such as [...] Read more.

In this work of quercetin’s anti-proliferation action on A. flavus, we revealed that quercetin can effectively hamper the proliferation of A. flavus in dose-effect and time-effect relationships. We tested whether quercetin induced apoptosis in A. flavus via various detection methods, such as phosphatidylserine externalization and Hoechst 33342 staining. The results showed that quercetin had no effect on phosphatidylserine externalization and cell nucleus in A. flavus. Simultaneously, quercetin reduced the levels of reactive oxygen species (ROS). For a better understanding of the molecular mechanism of the A. flavus response to quercetin, the RNA-Seq was used to explore the transcriptomic profiles of A. flavus. According to transcriptome sequencing data, quercetin inhibits the proliferation and aflatoxin biosynthesis by regulating the expression of development-related genes and aflatoxin production-related genes. These results will provide some theoretical basis for quercetin as an anti-mildew agent resource. Full article

(This article belongs to the Section Mycotoxins)

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19 pages, 3819 KiB

Open AccessEditor’s ChoiceArticle

Proteomic Analysis of Novel Components of Nemopilema nomurai Jellyfish Venom: Deciphering the Mode of Action

by Indu Choudhary, Du Hyeon Hwang, Hyunkyoung Lee, Won Duk Yoon, Jinho Chae, Chang Hoon Han, Seungshic Yum, Changkeun Kang and Euikyung Kim

Toxins 2019, 11(3), 153; https://doi.org/10.3390/toxins11030153 - 8 Mar 2019

Cited by 25 | Viewed by 5551

Abstract

Nowadays, proliferation of jellyfish has become a severe matter in many coastal areas around the world. Jellyfish Nemopilema nomurai is one of the most perilous organisms and leads to significant deleterious outcomes such as harm to the fishery, damage the coastal equipment, and [...] Read more.

Nowadays, proliferation of jellyfish has become a severe matter in many coastal areas around the world. Jellyfish Nemopilema nomurai is one of the most perilous organisms and leads to significant deleterious outcomes such as harm to the fishery, damage the coastal equipment, and moreover, its envenomation can be hazardous to the victims. Till now, the components of Nemopilema nomurai venom (NnV) are unknown owing to scant transcriptomics and genomic data. In the current research, we have explored a proteomic approach to identify NnV components and their interrelation with pathological effects caused by the jellyfish sting. Altogether, 150 proteins were identified, comprising toxins and other distinct proteins that are substantial in nematocyst genesis and nematocyte growth by employing two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI/TOF/MS). The identified toxins are phospholipase A2, phospholipase D Li Sic Tox beta IDI, a serine protease, putative Kunitz-type serine protease inhibitor, disintegrin and metalloproteinase, hemolysin, leukotoxin, three finger toxin MALT0044C, allergens, venom prothrombin activator trocarin D, tripeptide Gsp 9.1, and along with other toxin proteins. These toxins are relatively well characterized in the venoms of other poisonous species to induce pathogenesis, hemolysis, inflammation, proteolysis, blood coagulation, cytolysis, hemorrhagic activity, and type 1 hypersensitivity, suggesting that these toxins in NnV can also cause similar deleterious consequences. Our proteomic works indicate that NnV protein profile represents valuable source which leads to better understanding the clinical features of the jellyfish stings. As one of the largest jellyfish in the world, Nemopilema nomurai sting is considered to be harmful to humans due to its potent toxicity. The identification and functional characterization of its venom components have been poorly described and are beyond our knowledge. Here is the first report demonstrating the methodical overview of NnV proteomics research, providing significant information to understand the mechanism of NnV envenomation. Our proteomics findings can provide a platform for novel protein discovery and development of practical ways to deal with jellyfish stings on human beings. Full article

(This article belongs to the Section Animal Venoms)

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Toxins, Volume 11, Issue 3 (March 2019) – 50 articles

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