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Toxins, Volume 13, Issue 1 (January 2021) – 72 articles

Cover Story (view full-size image): A yeast synthetic–lethal phenotypic screening assay was used to identify new bacterial virulence factors and small-molecule inhibitors against a bacterial family of mono-ADP-ribosyltransferase toxins. The steps include: (1) Saccharomyces cerevisiae is grown to log phase and transformed with linear CUPI plasmid and toxin gene insert flanked by 20 base-pairs homologous to the plasmid; (2) successful transformants are grown in selective media containing Cu2+ to induce a growth-defect phenotype; (3) subsequently, small-molecule compounds are added to the culture medium upon induction of the toxin gene to reverse the phenotype; and (4) inhibitors that block the growth-defect phenotype are further characterized and developed for their therapeutic potential. This review offers an overview of structure–function work accomplished to develop antivirulence compounds against these bacterial toxins. [...] Read more.
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Open AccessArticle
The Potential of Peroxidases Extracted from the Spent Mushroom (Flammulina velutipes) Substrate Significantly Degrade Mycotoxin Deoxynivalenol
Toxins 2021, 13(1), 72; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010072 - 19 Jan 2021
Viewed by 374
Abstract
Little is known about the degradability of mycotoxin deoxynivalenol (DON) by the spent mushroom substrate (SMS)-derived manganese peroxidase (MnP) and lignin peroxidase (LiP) and its potential. The present study investigated the growth inhibition of Fusarium graminearum KR1 and the degradation of DON by [...] Read more.
Little is known about the degradability of mycotoxin deoxynivalenol (DON) by the spent mushroom substrate (SMS)-derived manganese peroxidase (MnP) and lignin peroxidase (LiP) and its potential. The present study investigated the growth inhibition of Fusarium graminearum KR1 and the degradation of DON by MnP and LiP extracted from SMS. The results from the 7-day treatment period showed that mycelium inhibition of F. graminearum KR1 by MnP and LiP were 23.7% and 74.7%, respectively. Deoxynivalenol production in the mycelium of F. graminearum KR1 was undetectable after treatment with 50 U/mL of MnP or LiP for 7 days. N-acetyl-D-glucosamine (GlcNAc) content and chitinase activity both increased in the hyphae of F. graminearum KR1 after treatment with MnP and LiP for 1, 3, and 6 h, respectively. At 12 h, only the LiP-treated group had higher chitinase activity and GlcNAc content than those of the control group (p < 0.05). However, more than 60% of DON degradabilities (0.5 mg/kg, 1 h) were observed under various pH values (2.5, 4.5, and 6.5) in both MnP (50 U/g) and LiP (50 U/g) groups, while DON degradability at 1 mg/kg was 85.5% after 50 U/g of LiP treatment for 7 h in simulated pig gastrointestinal tracts. Similarly, DON degradability at 5 mg/kg was 67.1% after LiP treatment for 4.5 h in simulated poultry gastrointestinal tracts. The present study demonstrated that SMS-extracted peroxidases, particularly LiP, could effectively degrade DON and inhibit the mycelium growth of F. graminearum KR1. Full article
(This article belongs to the Special Issue Effects of Mycotoxins on Health and Performance in Animals)
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Open AccessArticle
Molecular Characterization of the Enterohemolysin Gene (ehxA) in Clinical Shiga Toxin-Producing Escherichia coli Isolates
Toxins 2021, 13(1), 71; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010071 - 19 Jan 2021
Viewed by 411
Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) is an important foodborne pathogen with the ability to cause bloody diarrhea (BD) and hemolytic uremic syndrome (HUS). Little is known about enterohemolysin-encoded by ehxA. Here we investigated the prevalence and diversity of ehxA in 239 [...] Read more.
Shiga toxin (Stx)-producing Escherichia coli (STEC) is an important foodborne pathogen with the ability to cause bloody diarrhea (BD) and hemolytic uremic syndrome (HUS). Little is known about enterohemolysin-encoded by ehxA. Here we investigated the prevalence and diversity of ehxA in 239 STEC isolates from human clinical samples. In total, 199 out of 239 isolates (83.26%) were ehxA positive, and ehxA was significantly overrepresented in isolates carrying stx2a + stx2c (p < 0.001) and eae (p < 0.001). The presence of ehxA was significantly associated with BD and serotype O157:H7. Five ehxA subtypes were identified, among which, ehxA subtypes B, C, and F were overrepresented in eae-positive isolates. All O157:H7 isolates carried ehxA subtype B, which was related to BD and HUS. Three ehxA groups were observed in the phylogenetic analysis, namely, group Ⅰ (ehxA subtype A), group Ⅱ (ehxA subtype B, C, and F), and group Ⅲ (ehxA subtype D). Most BD- and HUS-associated isolates were clustered into ehxA group Ⅱ, while ehxA group Ⅰ was associated with non-bloody stool and individuals ≥10 years of age. The presence of ehxA + eae and ehxA + eae + stx2 was significantly associated with HUS and O157:H7 isolates. In summary, this study showed a high prevalence and the considerable genetic diversity of ehxA among clinical STEC isolates. The ehxA genotypes (subtype B and phylogenetic group Ⅱ) could be used as risk predictors, as they were associated with severe clinical symptoms, such as BD and HUS. Furthermore, ehxA, together with stx and eae, can be used as a risk predictor for HUS in STEC infections. Full article
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Open AccessEditorial
Special Issue: Immune Dysfunction in Uremia
Toxins 2021, 13(1), 70; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010070 - 19 Jan 2021
Viewed by 278
Abstract
This Special Issue of Toxins focusses on the interconnected factors interfering with the immune response in uremic patients [...] Full article
(This article belongs to the Special Issue Immune Dysfunction in Uremia)
Open AccessArticle
A Wolf in Another Wolf’s Clothing: Post-Genomic Regulation Dictates Venom Profiles of Medically-Important Cryptic Kraits in India
Toxins 2021, 13(1), 69; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010069 - 19 Jan 2021
Cited by 1 | Viewed by 924
Abstract
The Common Krait (Bungarus caeruleus) shares a distribution range with many other ‘phenotypically-similar’ kraits across the Indian subcontinent. Despite several reports of fatal envenomings by other Bungarus species, commercial Indian antivenoms are only manufactured against B. caeruleus. It is, therefore, [...] Read more.
The Common Krait (Bungarus caeruleus) shares a distribution range with many other ‘phenotypically-similar’ kraits across the Indian subcontinent. Despite several reports of fatal envenomings by other Bungarus species, commercial Indian antivenoms are only manufactured against B. caeruleus. It is, therefore, imperative to understand the distribution of genetically distinct lineages of kraits, the compositional differences in their venoms, and the consequent impact of venom variation on the (pre)clinical effectiveness of antivenom therapy. To address this knowledge gap, we conducted phylogenetic and comparative venomics investigations of kraits in Southern and Western India. Phylogenetic reconstructions using mitochondrial markers revealed a new species of krait, Romulus’ krait (Bungarus romulusi sp. nov.), in Southern India. Additionally, we found that kraits with 17 mid-body dorsal scale rows in Western India do not represent a subspecies of the Sind Krait (B. sindanus walli) as previously believed, but are genetically very similar to B. sindanus in Pakistan. Furthermore, venom proteomics and comparative transcriptomics revealed completely contrasting venom profiles. While the venom gland transcriptomes of all three species were highly similar, venom proteomes and toxicity profiles differed significantly, suggesting the prominent role of post-genomic regulatory mechanisms in shaping the venoms of these cryptic kraits. In vitro venom recognition and in vivo neutralisation experiments revealed a strong negative impact of venom variability on the preclinical performance of commercial antivenoms. While the venom of B. caeruleus was neutralised as per the manufacturer’s claim, performance against the venoms of B. sindanus and B. romulusi was poor, highlighting the need for regionally-effective antivenoms in India. Full article
(This article belongs to the Special Issue Drivers of Venom Potency across the Animal Kingdom)
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Open AccessArticle
Toxic Shock Syndrome Toxin 1 Induces Immune Response via the Activation of NLRP3 Inflammasome
Toxins 2021, 13(1), 68; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010068 - 18 Jan 2021
Viewed by 326
Abstract
Staphylococcus aureus is a Gram-positive opportunistic pathogen which causes infections in a variety of vertebrates. Virulence factors are the main pathogenesis of S. aureus as a pathogen, which induce the host’s innate and adaptive immune responses. Toxic shock syndrome toxin 1 (TSST-1) is [...] Read more.
Staphylococcus aureus is a Gram-positive opportunistic pathogen which causes infections in a variety of vertebrates. Virulence factors are the main pathogenesis of S. aureus as a pathogen, which induce the host’s innate and adaptive immune responses. Toxic shock syndrome toxin 1 (TSST-1) is one of the most important virulence factors of S. aureus. However, the role of nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) in TSST-1-induced innate immune response is still unclear. Here, purified recombinant TSST-1 (rTSST-1) was prepared and used to stimulate mouse peritoneal macrophages. The results showed that under the action of adenosine-triphosphate (ATP), rTSST-1 significantly induced interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) production in mouse macrophages and the production was dose-dependent. In addition, rTSST-1+ATP-stimulated cytokine production in macrophage depends on the activation of toll like receptor 4 (TLR4), but not TLR2 on the cells. Furthermore, the macrophages of NLRP3−/− mice stimulated with rTSST-1+ATP showed significantly low levels of IL-1β production compared to that of wild-type mice. These results demonstrated that TSST-1 can induce the expression of inflammatory cytokines in macrophages via the activation of the TLR4 and NLRP3 signaling pathways. Our study provides new information about the mechanism of the TSST-1-inducing host’s innate immune responses. Full article
(This article belongs to the Section Bacterial Toxins)
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Open AccessArticle
α-Solanine Causes Cellular Dysfunction of Human Trophoblast Cells via Apoptosis and Autophagy
Toxins 2021, 13(1), 67; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010067 - 18 Jan 2021
Viewed by 367
Abstract
The trophoblast, an embryonic tissue, exerts a crucial role in the processes of implantation and placentation. Toxins in food can cause malfunction of trophoblasts, resulting in apoptosis, oxidative stress, and abnormal angiogenesis. α-solanine, a steroidal glycoalkaloid, has antitumor properties on several cancer cells. [...] Read more.
The trophoblast, an embryonic tissue, exerts a crucial role in the processes of implantation and placentation. Toxins in food can cause malfunction of trophoblasts, resulting in apoptosis, oxidative stress, and abnormal angiogenesis. α-solanine, a steroidal glycoalkaloid, has antitumor properties on several cancer cells. However, its effect on human trophoblasts has not been elucidated. In this study, human extravillous trophoblast HTR-8/SVneo cells were exposed to α-solanine. Cellular functions including proliferation, migration, invasion, tube formation, and apoptosis were assessed. To monitor autophagic flux, trophoblasts were transfected with a mCherry-GFP-LC3B vector using lentiviral transduction, and expression of autophagy-related biomarkers including Beclin 1, Atgl3, and microtubule-associated protein 1 light chain-3 (MAP1-LC3) were detected. The results show that application of 20 μM α-solanine or above inhibited the cell viability, migration, invasion, and tube formation of the human trophoblast. Cell cycle was arrested at S and G2/M phases in response to 30 μM α-solanine. α-solanine induced apoptosis of HTR-8/SVneo cells and triggered autophagy by increasing the autophagic gene expression and stimulating the formation of autophagosome and autophagic flux. In conclusion, α-solanine can impair the functions of human trophoblast cells via activation of cell apoptosis and autophagy. Full article
(This article belongs to the Special Issue Plant Toxins Affecting Animal Health and Production)
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Open AccessArticle
Enhanced Photocatalytic Removal of Cyanotoxins by Al-Doped ZnO Nanoparticles with Visible-LED Irradiation
Toxins 2021, 13(1), 66; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010066 - 17 Jan 2021
Viewed by 419
Abstract
The ZnO-based visible-LED photocatalytic degradation and mineralization of two typical cyanotoxins, microcystin-LR (MC-LR), and anatoxin-A were examined. Al-doped ZnO nanoparticle photocatalysts, in Al:Zn ratios between 0 and 5 at.%, were prepared via sol-gel method and exhaustively characterized by X-ray diffraction, transmission electron microscopy, [...] Read more.
The ZnO-based visible-LED photocatalytic degradation and mineralization of two typical cyanotoxins, microcystin-LR (MC-LR), and anatoxin-A were examined. Al-doped ZnO nanoparticle photocatalysts, in Al:Zn ratios between 0 and 5 at.%, were prepared via sol-gel method and exhaustively characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, and nitrogen adsorption-desorption isotherms. With both cyanotoxins, increasing the Al content enhances the degradation kinetics, hence the use of nanoparticles with 5 at.% Al content (A5ZO). The dosage affected both cyanotoxins similarly, and the photocatalytic degradation kinetics improved with photocatalyst concentrations between 0.5 and 1.0 g L−1. Nevertheless, the pH study revealed that the chemical state of a species decisively facilitates the mutual interaction of cyanotoxin and photocatalysts. A5ZO nanoparticles achieved better outcomes than other photocatalysts to date, and after 180 min, the mineralization of anatoxin-A was virtually complete in weak alkaline medium, whereas only 45% of MC-LR was in neutral conditions. Moreover, photocatalyst reusability is clear for anatoxin-A, but it is adversely affected for MC-LR. Full article
(This article belongs to the Special Issue Removal of Cyanobacteria and Cyanotoxins in Waters)
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Open AccessReview
Toxic Effect of Aflatoxins in Dogs Fed Contaminated Commercial Dry Feed: A Review
Toxins 2021, 13(1), 65; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010065 - 15 Jan 2021
Viewed by 433
Abstract
Since its first patent (1897), commercial dry feed (CDF) for dogs has diversified its formulation to meet the nutritional needs of different breeds, age, or special conditions and establish a foundation for integration of these pets into urban lifestyles. The risk of aflatoxicosis [...] Read more.
Since its first patent (1897), commercial dry feed (CDF) for dogs has diversified its formulation to meet the nutritional needs of different breeds, age, or special conditions and establish a foundation for integration of these pets into urban lifestyles. The risk of aflatoxicosis in dogs has increased because the ingredients used to formulate CDF have also proliferated, making it difficult to ensure the quality required of each to achieve the safety of the entire CDF. This review contains a description of the fungi and aflatoxins detected in CDF and the ingredients commonly used for their formulation. The mechanisms of action and pathogenic effects of aflatoxins are outlined; as well as the clinical findings, and macroscopic and microscopic lesions found in aflatoxicosis in dogs. In addition, alternatives for diagnosis, treatment, and control of aflatoxins (AF) in CDF are analyzed, such as biomarkers of effect, improvement of blood coagulation, rate of elimination of AF, control of secondary infection, protection of gastric mucosa, reduction of oxidative stress, use of chemo-protectors, sequestrants, grain-free CDF, biocontrol, and maximum permitted limits, are also included. Full article
(This article belongs to the Special Issue Toxic Effect of Mycotoxins)
Open AccessBrief Report
Switching Shiga Toxin (Stx) Type from Stx2d to Stx2a but Not Stx2c Alters Virulence of Stx-Producing Escherichia coli (STEC) Strain B2F1 in Streptomycin (Str)-Treated Mice
Toxins 2021, 13(1), 64; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010064 - 15 Jan 2021
Viewed by 297
Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) strain B2F1 produces Stx type 2d, a toxin that becomes more toxic towards Vero cells in the presence of intestinal mucus. STEC that make Stx2d are more pathogenic to streptomycin (Str)-treated mice than most STEC that produce [...] Read more.
Shiga toxin (Stx)-producing Escherichia coli (STEC) strain B2F1 produces Stx type 2d, a toxin that becomes more toxic towards Vero cells in the presence of intestinal mucus. STEC that make Stx2d are more pathogenic to streptomycin (Str)-treated mice than most STEC that produce Stx2a or Stx2c. However, purified Stx2d is only 2- or 7-fold more toxic by the intraperitoneal route than Stx2a or Stx2c, respectively. We hypothesized, therefore, that the toxicity differences among Stx2a, Stx2c, and Stx2d occur at the level of delivery from the intestine. To evaluate that hypothesis, we altered the toxin type produced by stx2d+ mouse virulent O91:H21 clinical isolate B2F1 to Stx2a or Stx2c. Because B2F1 encodes two copies of stx2d, we did these studies in a derivative of B2F1 in which stx2d1 was deleted. Although the strains were equivalently virulent to the Str-treated mice at the 1010 dose, the B2F1 strain that produced Stx2a was attenuated relative to the ones that produced Stx2d or Stx2c when administered at 103 CFU/mouse. We next compared the oral toxicities of purified Stx2a, Stx2c, and Stx2d. We found that purified Stx2d is more toxic than Stx2a or Stx2c upon oral administration at 4 µg/mouse. Taken together, these studies suggest that Stx2 toxins are most potent when delivered directly from the bacterium. Furthermore, because Stx2d and Stx2c have the identical amino acid composition in the toxin B subunit, our results indicate that the virulence difference between Stx2a and Stx2d and Stx2c resides in the B or binding subunit of the toxins. Full article
(This article belongs to the Special Issue Escherichia coli Toxins and Intestinal Diseases)
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Open AccessArticle
Populations of Helicoverpa zea (Boddie) in the Southeastern United States are Commonly Resistant to Cry1Ab, but Still Susceptible to Vip3Aa20 Expressed in MIR 162 Corn
Toxins 2021, 13(1), 63; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010063 - 15 Jan 2021
Cited by 1 | Viewed by 319
Abstract
The corn earworm, Helicoverpa zea (Boddie), is a major pest targeted by pyramided Bacillus thuringiensis (Bt) corn and cotton in the U.S. Cry1Ab is one of the first insecticidal toxins used in Bt crops, while Vip3A is a relatively new toxin that has [...] Read more.
The corn earworm, Helicoverpa zea (Boddie), is a major pest targeted by pyramided Bacillus thuringiensis (Bt) corn and cotton in the U.S. Cry1Ab is one of the first insecticidal toxins used in Bt crops, while Vip3A is a relatively new toxin that has recently been incorporated into Cry corn with event MIR 162 and Cry cotton varieties to generate pyramided Bt traits targeting lepidopteran pests including H. zea. The objectives of this study were to determine the current status and distribution of the Cry1Ab resistance, and evaluate the susceptibility to Vip3Aa20 expressed in MIR 162 corn in H. zea in the southeastern U.S. During 2018 and 2019, 32 H. zea populations were collected from non-Bt corn (19 populations), Cry corn (12), and Cry/Vip3A cotton (1) across major corn areas in seven southeastern states of the U.S. Susceptibility of these populations to Cry1Ab and Vip3Aa20 was determined using diet-overlay bioassays. Compared to a known susceptible insect strain, 80% of the field populations were 13- to >150-fold resistant to Cry1Ab, while their response to Vip3Aa20 ranged from >11-fold more susceptible to 9-fold more tolerant. Mean susceptibility to each Bt toxin was not significantly different between the two groups of the populations collected from non-Bt and Bt crops, as well as between the two groups of the populations collected during 2018 and 2019. The results show that resistance to Cry1Ab in H. zea is widely distributed across the region. However, the Cry1Ab-resistant populations are not cross-resistant to Vip3Aa20, and H. zea in the region is still susceptible to the Vip3Aa20 toxin. Vip3Aa20 concentrations between 5 and 10 µg/cm2 may be used as diagnostic concentrations for susceptibility monitoring in future. Additional studies are necessary to elucidate the impact of the selection with Bt corn on resistance evolution in H. zea to Vip3A cotton in the U.S. Full article
(This article belongs to the Special Issue The Pivotal Role of Toxins in Insects-Bacteria Interactions)
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Open AccessArticle
Pathogenic Pore Forming Proteins of Plasmodium Triggers the Necrosis of Endothelial Cells Attributed to Malaria Severity
Toxins 2021, 13(1), 62; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010062 - 15 Jan 2021
Viewed by 378
Abstract
Severe malaria caused by Plasmodium falciparum poses a major global health problem with high morbidity and mortality. P. falciparum harbors a family of pore-forming proteins (PFPs), known as perforin like proteins (PLPs), which are structurally equivalent to prokaryotic PFPs. These PLPs are secreted [...] Read more.
Severe malaria caused by Plasmodium falciparum poses a major global health problem with high morbidity and mortality. P. falciparum harbors a family of pore-forming proteins (PFPs), known as perforin like proteins (PLPs), which are structurally equivalent to prokaryotic PFPs. These PLPs are secreted from the parasites and, they contribute to disease pathogenesis by interacting with host cells. The severe malaria pathogenesis is associated with the dysfunction of various barrier cells, including endothelial cells (EC). Several factors, including PLPs secreted by parasites, contribute to the host cell dysfunction. Herein, we have tested the hypothesis that PLPs mediate dysfunction of barrier cells and might have a role in disease pathogenesis. We analyzed various dysfunctions in barrier cells following rPLP2 exposure and demonstrate that it causes an increase in intracellular Ca2+ levels. Additionally, rPLP2 exposed barrier cells displayed features of cell death, including Annexin/PI positivity, depolarized the mitochondrial membrane potential, and ROS generation. We have further performed the time-lapse video microscopy of barrier cells and found that the treatment of rPLP2 triggers their membrane blebbing. The cytoplasmic localization of HMGB1, a marker of necrosis, further confirmed the necrotic type of cell death. This study highlights the role of parasite factor PLP in endothelial dysfunction and provides a rationale for the design of adjunct therapies against severe malaria. Full article
(This article belongs to the Special Issue Bacterial Toxins: Protein Folding and Membrane Interactions)
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Open AccessEditorial
Methicillin-Resistant Staphylococci and Macrococci at the Interface of Human and Animal Health
Toxins 2021, 13(1), 61; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010061 - 14 Jan 2021
Viewed by 302
Abstract
The global impact of methicillin-resistant Staphylococcus aureus (MRSA) clonal lineages on human and animal health continues, even considering the decreasing MRSA rates in some parts of the world [...] Full article
Open AccessArticle
A Neurotoxic Snake Venom without Phospholipase A2: Proteomics and Cross-Neutralization of the Venom from Senegalese Cobra, Naja senegalensis (Subgenus: Uraeus)
Toxins 2021, 13(1), 60; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010060 - 14 Jan 2021
Viewed by 499
Abstract
The Senegalese cobra, Naja senegalensis, is a non-spitting cobra species newly erected from the Naja haje complex. Naja senegalensis causes neurotoxic envenomation in Western Africa but its venom properties remain underexplored. Applying a protein decomplexation proteomic approach, this study unveiled the unique [...] Read more.
The Senegalese cobra, Naja senegalensis, is a non-spitting cobra species newly erected from the Naja haje complex. Naja senegalensis causes neurotoxic envenomation in Western Africa but its venom properties remain underexplored. Applying a protein decomplexation proteomic approach, this study unveiled the unique complexity of the venom composition. Three-finger toxins constituted the major component, accounting for 75.91% of total venom proteins. Of these, cardiotoxin/cytotoxin (~53%) and alpha-neurotoxins (~23%) predominated in the venom proteome. Phospholipase A2, however, was not present in the venom, suggesting a unique snake venom phenotype found in this species. The venom, despite the absence of PLA2, is highly lethal with an intravenous LD50 of 0.39 µg/g in mice, consistent with the high abundance of alpha-neurotoxins (predominating long neurotoxins) in the venom. The hetero-specific VINS African Polyvalent Antivenom (VAPAV) was immunoreactive to the venom, implying conserved protein antigenicity in the venoms of N. senegalensis and N. haje. Furthermore, VAPAV was able to cross-neutralize the lethal effect of N. senegalensis venom but the potency was limited (0.59 mg venom completely neutralized per mL antivenom, or ~82 LD50 per ml of antivenom). The efficacy of antivenom should be further improved to optimize the treatment of cobra bite envenomation in Africa. Full article
(This article belongs to the Special Issue Interactions of Snake Venoms and Antivenoms: Prelude to Protection)
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Open AccessArticle
Effects of Sodium Silicate Complex against Hemorrhagic Activities Induced by Protobothrops mucrosquamatus Venom
Toxins 2021, 13(1), 59; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010059 - 14 Jan 2021
Viewed by 357
Abstract
Protobothrops mucrosquamatus poses a serious medical threat to humans in Southern and Southeastern Asia. Hemorrhage is one of the conspicuous toxicities related to the pathology of P. mucrosquamatus envenoming. Previous in vitro and in vivo studies showed that a silica-derived reagent, sodium silicate [...] Read more.
Protobothrops mucrosquamatus poses a serious medical threat to humans in Southern and Southeastern Asia. Hemorrhage is one of the conspicuous toxicities related to the pathology of P. mucrosquamatus envenoming. Previous in vitro and in vivo studies showed that a silica-derived reagent, sodium silicate complex (SSC), was able to neutralize hemorrhagic and proteolytic activities induced by pit viper venoms, including Crotalus atrox, Agkistrodoncontortrix contortrix and Agkistrodon piscivorus leucostoma. In this study, we validated that SSC could neutralize enzymatic and toxic effects caused by the venom of P. mucrosquamatus. We found that SSC inhibited the hemolytic and proteolytic activities induced by P. mucrosquamatus venom in vitro. In addition, we demonstrated that SSC could block intradermal hemorrhage caused by P. mucrosquamatus venom in a mouse model. Finally, SSC could neutralize lethal effects of P. mucrosquamatus venom in the mice. Therefore, SSC is a candidate for further development as a potential onsite first-aid treatment for P. mucrosquamatus envenoming. Full article
(This article belongs to the Section Animal Venoms)
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Open AccessReview
Botulinum Toxin: An Update on Pharmacology and Newer Products in Development
Toxins 2021, 13(1), 58; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010058 - 14 Jan 2021
Viewed by 544
Abstract
Since its introduction as a treatment for strabismus, botulinum toxin (BoNT) has had a phenomenal journey and is now recommended as first-line treatment for focal dystonia, despite short-term clinical benefits and the risks of adverse effects. To cater for the high demand across [...] Read more.
Since its introduction as a treatment for strabismus, botulinum toxin (BoNT) has had a phenomenal journey and is now recommended as first-line treatment for focal dystonia, despite short-term clinical benefits and the risks of adverse effects. To cater for the high demand across various medical specialties, at least six US Food and Drug Administration (FDA)-approved formulations of BoNT are currently available for diverse labelled indications. The toxo-pharmacological properties of these formulations are not uniform and thus should not be used interchangeably. Synthetic BoNTs and BoNTs from non-clostridial sources are not far from clinical use. Moreover, the study of mutations in naturally occurring toxins has led to modulation in the toxo-pharmacokinetic properties of BoNTs, including the duration and potency. We present an overview of the toxo-pharmacology of conventional and novel BoNT preparations, including those awaiting imminent translation from the laboratory to the clinic. Full article
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Open AccessArticle
Monitoring Lipophilic Toxins in Seawater Using Dispersive Liquid—Liquid Microextraction and Liquid Chromatography with Triple Quadrupole Mass Spectrometry
Toxins 2021, 13(1), 57; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010057 - 13 Jan 2021
Viewed by 352
Abstract
The use of dispersive liquid–liquid microextraction (DLLME) is proposed for the preconcentration of thirteen lipophilic marine toxins in seawater samples. For this purpose, 0.5 mL of methanol and 440 µL of chloroform were injected into 12 mL of sample. The enriched organic phase, [...] Read more.
The use of dispersive liquid–liquid microextraction (DLLME) is proposed for the preconcentration of thirteen lipophilic marine toxins in seawater samples. For this purpose, 0.5 mL of methanol and 440 µL of chloroform were injected into 12 mL of sample. The enriched organic phase, once evaporated and reconstituted in methanol, was analyzed by reversed-phase liquid chromatography with triple-quadrupole tandem mass spectrometry. A central composite design multivariate method was used to optimize the interrelated parameters affecting DLLME efficiency. The absence of any matrix effect in the samples allowed them to be quantified against aqueous standards. The optimized procedure was validated by recovery studies, which provided values in the 82–123% range. The detection limits varied between 0.2 and 5.7 ng L−1, depending on the analyte, and the intraday precision values were in the 0.1–7.5% range in terms of relative standard deviation. Ten water samples taken from different points of the Mar Menor lagoon were analyzed and were found to be free of the studied toxins. Full article
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Open AccessConference Report
Report of the Vth Workshop of the Spanish National Network on Mycotoxins and Toxigenic Fungi and Their Decontamination Processes (MICOFOOD), 10–11 December 2020
Toxins 2021, 13(1), 56; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010056 - 13 Jan 2021
Viewed by 371
Open AccessArticle
Mapping the DNA-Binding Motif of Scabin Toxin, a Guanine Modifying Enzyme from Streptomyces scabies
Toxins 2021, 13(1), 55; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010055 - 13 Jan 2021
Viewed by 404
Abstract
Scabin is a mono-ADP-ribosyltransferase toxin/enzyme and possible virulence factor produced by the agriculture pathogen, Streptomyces scabies. Recently, molecular dynamic approaches and MD simulations revealed its interaction with both NAD+ and DNA substrates. An Essential Dynamics Analysis identified a crab-claw-like mechanism, including [...] Read more.
Scabin is a mono-ADP-ribosyltransferase toxin/enzyme and possible virulence factor produced by the agriculture pathogen, Streptomyces scabies. Recently, molecular dynamic approaches and MD simulations revealed its interaction with both NAD+ and DNA substrates. An Essential Dynamics Analysis identified a crab-claw-like mechanism, including coupled changes in the exposed motifs, and the Rβ1-RLa-NLc-STTβ2-WPN-WARTT-(QxE)ARTT sequence motif was proposed as a catalytic signature of the Pierisin family of DNA-acting toxins. A new fluorescence assay was devised to measure the kinetics for both RNA and DNA substrates. Several protein variants were prepared to probe the Scabin-NAD-DNA molecular model and to reveal the reaction mechanism for the transfer of ADP-ribose to the guanine base in the DNA substrate. The results revealed that there are several lysine and arginine residues in Scabin that are important for binding the DNA substrate; also, key residues such as Asn110 in the mechanism of ADP-ribose transfer to the guanine base were identified. The DNA-binding residues are shared with ScARP from Streptomyces coelicolor but are not conserved with Pierisin-1, suggesting that the modification of guanine bases by ADP-ribosyltransferases is divergent even in the Pierisin family. Full article
(This article belongs to the Special Issue Structure and Function of Bacterial ADP-Ribosylation Toxins)
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Open AccessArticle
Investigating Multi-Mycotoxin Exposure in Occupational Settings: A Biomonitoring and Airborne Measurement Approach
Toxins 2021, 13(1), 54; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010054 - 13 Jan 2021
Viewed by 392
Abstract
Investigating workplace exposure to mycotoxins is of the utmost importance in supporting the implementation of preventive measures for workers. The aim of this study was to provide tools for measuring mycotoxins in urine and airborne samples. A multi-class mycotoxin method was developed in [...] Read more.
Investigating workplace exposure to mycotoxins is of the utmost importance in supporting the implementation of preventive measures for workers. The aim of this study was to provide tools for measuring mycotoxins in urine and airborne samples. A multi-class mycotoxin method was developed in urine for the determination of aflatoxin B1, aflatoxin M1, ochratoxin A, ochratoxin α, deoxynivalenol, zearalenone, α-zearalenol, β-zearalenol, fumonisin B1, HT2-toxin and T2-toxin. Analysis was based on liquid chromatography–high resolution mass spectrometry. Sample pre-treatments included enzymatic digestion and an online or offline sample clean-up step. The method was validated according to the European Medicines Agency guidance procedures. In order to estimate external exposure, air samples collected with a CIP 10 (Capteur Individuel de Particules 10) personal dust sampler were analyzed for the quantification of up to ten mycotoxins, including aflatoxins, ochratoxin A, deoxynivalenol, zearalenone, fumonisin B1 and HT-2 toxin and T-2 toxin. The method was validated according to standards for workplace exposure to chemical and biological agents EN 482. Both methods, biomonitoring and airborne mycotoxin measurement, showed good analytical performances. They were successfully applied in a small pilot study to assess mycotoxin contamination in workers during cleaning of a grain elevator. We demonstrated that this approach was suitable for investigating occupational exposure to mycotoxins. Full article
(This article belongs to the Special Issue Occupational Exposure to Mycotoxins—Challenges and Ways Forward)
Open AccessReview
A Review of the Efficacy of FDA-Approved B. anthracis Anti-Toxin Agents When Combined with Antibiotic or Hemodynamic Support in Infection- or Toxin-Challenged Preclinical Models
Toxins 2021, 13(1), 53; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010053 - 13 Jan 2021
Viewed by 737
Abstract
Anti-toxin agents for severe B. anthracis infection will only be effective if they add to the benefit of the two mainstays of septic shock management, antibiotic therapy and titrated hemodynamic support. Both of these standard therapies could negate benefits related to anti-toxin treatment. [...] Read more.
Anti-toxin agents for severe B. anthracis infection will only be effective if they add to the benefit of the two mainstays of septic shock management, antibiotic therapy and titrated hemodynamic support. Both of these standard therapies could negate benefits related to anti-toxin treatment. At present, three anthrax anti-toxin antibody preparations have received US Food and Drug Administration (FDA) approval: Raxibacumab, Anthrax Immune Globulin Intravenous (AIGIV) and ETI-204. Each agent is directed at the protective antigen component of lethal and edema toxin. All three agents were compared to placebo in antibiotic-treated animal models of live B. anthracis infection, and Raxibacumab and AIGIV were compared to placebo when combined with standard hemodynamic support in a 96 h canine model of anthrax toxin-associated shock. However, only AIG has actually been administered to a group of infected patients, and this experience was not controlled and offers little insight into the efficacy of the agents. To provide a broader view of the potential effectiveness of these agents, this review examines the controlled preclinical experience either in antibiotic-treated B. anthracis models or in titrated hemodynamic-supported toxin-challenged canines. The strength and weaknesses of these preclinical experiences are discussed. Full article
(This article belongs to the Section Bacterial Toxins)
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Open AccessCommunication
Development and Evaluation of an Immuno-MALDI-TOF Mass Spectrometry Approach for Quantification of the Abrin Toxin in Complex Food Matrices
Toxins 2021, 13(1), 52; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010052 - 13 Jan 2021
Viewed by 484
Abstract
The toxin abrin found in the seeds of Abrus precatorius has attracted much attention regarding criminal and terroristic misuse over the past decade. Progress in analytical methods for a rapid and unambiguous identification of low abrin concentrations in complex matrices is essential. Here, [...] Read more.
The toxin abrin found in the seeds of Abrus precatorius has attracted much attention regarding criminal and terroristic misuse over the past decade. Progress in analytical methods for a rapid and unambiguous identification of low abrin concentrations in complex matrices is essential. Here, we report on the development and evaluation of a MALDI-TOF mass spectrometry approach for the fast, sensitive and robust abrin isolectin identification, differentiation and quantification in complex food matrices. The method combines immunoaffinity-enrichment with specific abrin antibodies, accelerated trypsin digestion and the subsequent MALDI-TOF analysis of abrin peptides using labeled peptides for quantification purposes. Following the optimization of the workflow, common and isoform-specific peptides were detected resulting in a ~38% sequence coverage of abrin when testing ng-amounts of the toxin. The lower limit of detection was established at 40 ng/mL in milk and apple juice. Isotope-labeled versions of abundant peptides with high ionization efficiency were added. The quantitative evaluation demonstrated an assay variability at or below 22% with a linear range up to 800 ng/mL. MALDI-TOF mass spectrometry allows for a simple and fast (<5 min) analysis of abrin peptides, without a time-consuming peptide chromatographic separation, thus constituting a relevant alternative to liquid chromatography-tandem mass spectrometry. Full article
(This article belongs to the Special Issue Antibodies for Toxins: From Detection to Therapeutics)
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Open AccessArticle
Quantitative Proteomic Profiling of Fungal Growth, Development, and Ochratoxin A Production in Aspergillus ochraceus on High- and Low-NaCl Cultures
Toxins 2021, 13(1), 51; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010051 - 13 Jan 2021
Viewed by 407
Abstract
Dry-cured meat products are worldwide food with high-salt content, and filamentous fungi are beneficial to the maturation process. However, some salt-tolerant strains of Aspergillus and Penicillium produce ochratoxin A (OTA) on these products and thus threaten food safety. In our study, proteomic analysis [...] Read more.
Dry-cured meat products are worldwide food with high-salt content, and filamentous fungi are beneficial to the maturation process. However, some salt-tolerant strains of Aspergillus and Penicillium produce ochratoxin A (OTA) on these products and thus threaten food safety. In our study, proteomic analysis was performed to reveal the mechanism of adaptability to high-salt environment by Aspergillus ochraceus. Twenty g/L and 70 g/L NaCl substrates were used to provide medium- and high-NaCl content environments, respectively. The NaCl addition could induce fungal growth, but only 20 g/L NaCl addition could induce spore production while 70 g/L repressed it. Proteomics analysis identified 2646 proteins in A. ochraceus fc-1, of which 237 and 251 were differentially expressed with 20 g/L and 70 g/L NaCl addition, respectively. Potential factors affecting fungal growth and development were identified by GO and KEGG analyses of biological process, cellular component, and molecular function terms. The results revealed that ergosterol synthesis pathway was significantly upregulated with 20 g/L and 70 g/L NaCl addition. However, fungal growth and development including OTA production were complex processes associated with many factors including nutrient uptake, cell membrane integrity, cell cycle, energy metabolism, intracellular redox homeostasis, protein synthesis and processing, autophagy, and secondary metabolism. Reactive oxygen species may be an important window to understand the mechanism that medium-salt content was conducive to intracellular signal transduction while high-salt content caused oxidative stress. The findings would help to improve the processes and storage conditions of dry-cured meat products. Full article
(This article belongs to the collection Ochratoxins-Collection)
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Open AccessArticle
Nicotinamide Attenuates the Progression of Renal Failure in a Mouse Model of Adenine-Induced Chronic Kidney Disease
Toxins 2021, 13(1), 50; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010050 - 11 Jan 2021
Viewed by 464
Abstract
Nicotinamide adenine dinucleotide (NAD+) supplies energy for deoxidation and anti-inflammatory reactions fostering the production of adenosine triphosphate (ATP). The kidney is an essential regulator of body fluids through the excretion of numerous metabolites. Chronic kidney disease (CKD) leads to the accumulation [...] Read more.
Nicotinamide adenine dinucleotide (NAD+) supplies energy for deoxidation and anti-inflammatory reactions fostering the production of adenosine triphosphate (ATP). The kidney is an essential regulator of body fluids through the excretion of numerous metabolites. Chronic kidney disease (CKD) leads to the accumulation of uremic toxins, which induces chronic inflammation. In this study, the role of NAD+ in kidney disease was investigated through the supplementation of nicotinamide (Nam), a precursor of NAD+, to an adenine-induced CKD mouse model. Nam supplementation reduced kidney inflammation and fibrosis and, therefore, prevented the progression of kidney disease. Notably, Nam supplementation also attenuated the accumulation of glycolysis and Krebs cycle metabolites that occurs in renal failure. These effects were due to increased NAD+ supply, which accelerated NAD+-consuming metabolic pathways. Our study suggests that Nam administration may be a novel therapeutic approach for CKD prevention. Full article
(This article belongs to the Special Issue The Functional Analysis of Uremic Toxins by Metabolomics)
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Open AccessArticle
In Vitro Neurotoxicity of Chinese Krait (Bungarus multicinctus) Venom and Neutralization by Antivenoms
Toxins 2021, 13(1), 49; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010049 - 11 Jan 2021
Viewed by 395
Abstract
Bungarus multicinctus, the Chinese krait, is a highly venomous elapid snake which causes considerable morbidity and mortality in southern China. B. multicinctus venom contains pre-synaptic PLA2 neurotoxins (i.e., β-bungarotoxins) and post-synaptic neurotoxins (i.e., α-bungarotoxins). We examined the in vitro neurotoxicity of [...] Read more.
Bungarus multicinctus, the Chinese krait, is a highly venomous elapid snake which causes considerable morbidity and mortality in southern China. B. multicinctus venom contains pre-synaptic PLA2 neurotoxins (i.e., β-bungarotoxins) and post-synaptic neurotoxins (i.e., α-bungarotoxins). We examined the in vitro neurotoxicity of B. multicinctus venom, and the efficacy of specific monovalent Chinese B. multicinctus antivenom, and Australian polyvalent elapid snake antivenom, against venom-induced neurotoxicity. B. multicinctus venom (1–10 μg/mL) abolished indirect twitches in the chick biventer cervicis nerve-muscle preparation as well as attenuating contractile responses to exogenous ACh and CCh, but not KCl. This indicates a post-synaptic neurotoxic action but myotoxicity was not evident. Given that post-synaptic α-neurotoxins have a more rapid onset than pre-synaptic neurotoxins, the activity of the latter in the whole venom will be masked. The prior addition of Chinese B. multicinctus antivenom (12 U/mL) or Australian polyvalent snake antivenom (15 U/mL), markedly attenuated the neurotoxic actions of B. multicinctus venom (3 μg/mL) and prevented the inhibition of contractile responses to ACh and CCh. The addition of B. multicinctus antivenom (60 U/mL), or Australian polyvalent snake antivenom (50 U/mL), at the t90 time point after the addition of B. multicinctus venom (3 μg/mL), did not restore the twitch height over 180 min. The earlier addition of B. multicinctus antivenom (60 U/mL), at the t20 or t50 time points, also failed to prevent the neurotoxic effects of the venom but did delay the time to abolish twitches based on a comparison of t90 values. Repeated washing of the preparation with physiological salt solution, commencing at the t20 time point, failed to reverse the neurotoxic effects of venom or delay the time to abolish twitches. This study showed that B. multicinctus venom displays marked in vitro neurotoxicity in a skeletal muscle preparation which is not reversed by antivenom. This does not appear to be related to antivenom efficacy, but due to the irreversible/pseudo-irreversible nature of the neurotoxins. Full article
(This article belongs to the Special Issue Interactions of Snake Venoms and Antivenoms: Prelude to Protection)
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Open AccessCommunication
Electric Eels Wield a Functional Venom Analogue
Toxins 2021, 13(1), 48; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010048 - 10 Jan 2021
Cited by 1 | Viewed by 414
Abstract
In this paper, I draw an analogy between the use of electricity by electric eels (Electrophorus electricus) to paralyze prey muscles and the use of venoms that paralyze prey by disrupting the neuromuscular junction. The eel’s strategy depends on the recently [...] Read more.
In this paper, I draw an analogy between the use of electricity by electric eels (Electrophorus electricus) to paralyze prey muscles and the use of venoms that paralyze prey by disrupting the neuromuscular junction. The eel’s strategy depends on the recently discovered ability of eels to activate prey motor neuron efferents with high-voltage pulses. Usually, eels use high voltage to cause brief, whole-body tetanus, thus preventing escape while swallowing prey whole. However, when eels struggle with large prey, or with prey held precariously, they often curl to bring their tail to the opposite side. This more than doubles the strength of the electric field within shocked prey, ensuring maximal stimulation of motor neuron efferents. Eels then deliver repeated volleys of high-voltage pulses at a rate of approximately 100 Hz. This causes muscle fatigue that attenuates prey movement, thus preventing both escape and defense while the eel manipulates and swallows the helpless animal. Presumably, the evolution of enough electrical power to remotely activate ion channels in prey efferents sets the stage for the selection of eel behaviors that functionally “poison” prey muscles. Full article
(This article belongs to the Special Issue The Behavioral Ecology of Venom)
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Open AccessArticle
Roles of Nutrient Limitation on Western Lake Erie CyanoHAB Toxin Production
Toxins 2021, 13(1), 47; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010047 - 09 Jan 2021
Viewed by 1374
Abstract
Cyanobacterial harmful algal bloom (CyanoHAB) proliferation is a global problem impacting ecosystem and human health. Western Lake Erie (WLE) typically endures two highly toxic CyanoHABs during summer: a Microcystis spp. bloom in Maumee Bay that extends throughout the western basin, and a Planktothrix [...] Read more.
Cyanobacterial harmful algal bloom (CyanoHAB) proliferation is a global problem impacting ecosystem and human health. Western Lake Erie (WLE) typically endures two highly toxic CyanoHABs during summer: a Microcystis spp. bloom in Maumee Bay that extends throughout the western basin, and a Planktothrix spp. bloom in Sandusky Bay. Recently, the USA and Canada agreed to a 40% phosphorus (P) load reduction to lessen the severity of the WLE blooms. To investigate phosphorus and nitrogen (N) limitation of biomass and toxin production in WLE CyanoHABs, we conducted in situ nutrient addition and 40% dilution microcosm bioassays in June and August 2019. During the June Sandusky Bay bloom, biomass production as well as hepatotoxic microcystin and neurotoxic anatoxin production were N and P co-limited with microcystin production becoming nutrient deplete under 40% dilution. During August, the Maumee Bay bloom produced microcystin under nutrient repletion with slight induced P limitation under 40% dilution, and the Sandusky Bay bloom produced anatoxin under N limitation in both dilution treatments. The results demonstrate the importance of nutrient limitation effects on microcystin and anatoxin production. To properly combat cyanotoxin and cyanobacterial biomass production in WLE, both N and P reduction efforts should be implemented in its watershed. Full article
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Open AccessReview
Aflatoxin Detoxification Using Microorganisms and Enzymes
Toxins 2021, 13(1), 46; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010046 - 09 Jan 2021
Viewed by 572
Abstract
Mycotoxin contamination causes significant economic loss to food and feed industries and seriously threatens human health. Aflatoxins (AFs) are one of the most harmful mycotoxins, which are produced by Aspergillus flavus, Aspergillus parasiticus, and other fungi that are commonly found in [...] Read more.
Mycotoxin contamination causes significant economic loss to food and feed industries and seriously threatens human health. Aflatoxins (AFs) are one of the most harmful mycotoxins, which are produced by Aspergillus flavus, Aspergillus parasiticus, and other fungi that are commonly found in the production and preservation of grain and feed. AFs can cause harm to animal and human health due to their toxic (carcinogenic, teratogenic, and mutagenic) effects. How to remove AF has become a major problem: biological methods cause no contamination, have high specificity, and work at high temperature, affording environmental protection. In the present research, microorganisms with detoxification effects researched in recent years are reviewed, the detoxification mechanism of microbes on AFs, the safety of degrading enzymes and reaction products formed in the degradation process, and the application of microorganisms as detoxification strategies for AFs were investigated. One of the main aims of the work is to provide a reliable reference strategy for biological detoxification of AFs. Full article
(This article belongs to the Special Issue Occurrence, Toxicity and Mitigation of Aflatoxins)
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Open AccessCommunication
Silver-109/Silver/Gold Nanoparticle-Enhanced Target Surface-Assisted Laser Desorption/Ionisation Mass Spectrometry—The New Methods for an Assessment of Mycotoxin Concentration on Building Materials
Toxins 2021, 13(1), 45; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010045 - 09 Jan 2021
Viewed by 405
Abstract
This study aimed to detect and quantify mycotoxins on building materials using innovative laser mass spectroscopy methods—silver-109/silver/gold nanoparticle-enhanced target surface-assisted laser desorption/ionisation mass spectrometry (109AgNPs, AgNPs and AuNPs SALDI). Results from SALDI-type methods were also compared with commonly used matrix-assisted laser [...] Read more.
This study aimed to detect and quantify mycotoxins on building materials using innovative laser mass spectroscopy methods—silver-109/silver/gold nanoparticle-enhanced target surface-assisted laser desorption/ionisation mass spectrometry (109AgNPs, AgNPs and AuNPs SALDI). Results from SALDI-type methods were also compared with commonly used matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. Standards of seven moulds mycotoxin in a final concentration of 100 µg/mL for patulin, citrinin, 3-nitropropionic acid, alternariol and 20 µg/mL for sterigmatocystin, cyclopiazonic acid, roquefortine C in the mixture were tested in pure solutions and after extraction from the plasterboards. Among the studied SALDI-type method, the lowest detection limits and the highest signal intensity of the mycotoxins tested were obtained with the use of 109AgNPs SALDI MS. The 109AgNPs method may be considered as an alternative to the currently most frequently used method MALDI MS and also liquid chromatography tandem mass spectrometry LC-MS/MS for mycotoxin determination. Future studies should attempt to use these methods for mass spectrometry imaging (MSI) to evaluate spatial distribution and depth of mycotoxin penetration into building materials. Full article
(This article belongs to the Special Issue Occurrence and Risk Assessment of Mycotoxins)
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Open AccessArticle
Topical Exposure to Nemopilema nomurai Venom Triggers Oedematogenic Effects: Enzymatic Contribution and Identification of Venom Metalloproteinase
Toxins 2021, 13(1), 44; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010044 - 08 Jan 2021
Viewed by 311
Abstract
Scyphozoan envenomation is featured as severe cutaneous damages due to the toxic effects of venom components released by the stinging nematocysts of a scyphozoan. However, the oedematogenic property and mechanism of scyphozoan venoms remain uninvestigated. Here, we present the oedematogenic properties of the [...] Read more.
Scyphozoan envenomation is featured as severe cutaneous damages due to the toxic effects of venom components released by the stinging nematocysts of a scyphozoan. However, the oedematogenic property and mechanism of scyphozoan venoms remain uninvestigated. Here, we present the oedematogenic properties of the nematocyst venom from Nemopilema nomurai (NnNV), a giant stinging scyphozoan in China, for the first time, using in vivo and in vitro models with class-specific inhibitors. NnNV was able to induce remarkable oedematogenic effects, including induction of significant oedema in the footpad and thigh of mouse, and increase in vascular permeability in the dorsal skin and kidney. Moreover, batimastat, a specific metalloproteinase inhibitor, could significantly reduce the Evan’s blue leakage in the damaged organs and attenuate paw oedema after 12 h, but exerted no influence on NnNV-induced thigh oedema. These observations suggested a considerable contribution of NnNV metalloproteinase-like components to the increased vasopermeability, and the participation was strongly suggested to be mediated by destroying the integrity of the vascular basement membrane. Moreover, partial isolation combined LC-MS/MS profiling led to identification of the protein species Nn65 with remarkable metalloproteinase activity. This study contributes to the understanding of the effector components underlying the cutaneous damages induced by scyphozoan stings. Full article
(This article belongs to the Section Marine and Freshwater Toxins)
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Open AccessArticle
Direct and Competitive Optical Grating Immunosensors for Determination of Fusarium Mycotoxin Zearalenone
Toxins 2021, 13(1), 43; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13010043 - 08 Jan 2021
Cited by 2 | Viewed by 391
Abstract
Novel optical waveguide lightmode spectroscopy (OWLS)-based immunosensor formats were developed for label-free detection of Fusarium mycotoxin zearalenone (ZON). To achieve low limits of detection (LODs), both immobilised antibody-based (direct) and immobilised antigen-based (competitive) assay setups were applied. Immunoreagents were immobilised on epoxy-, amino-, [...] Read more.
Novel optical waveguide lightmode spectroscopy (OWLS)-based immunosensor formats were developed for label-free detection of Fusarium mycotoxin zearalenone (ZON). To achieve low limits of detection (LODs), both immobilised antibody-based (direct) and immobilised antigen-based (competitive) assay setups were applied. Immunoreagents were immobilised on epoxy-, amino-, and carboxyl-functionalised sensor surfaces, and by optimising the immobilisation methods, standard sigmoid curves were obtained in both sensor formats. An outstanding LOD of 0.002 pg/mL was obtained for ZON in the competitive immunosensor setup with a dynamic detection range between 0.01 and 1 pg/mL ZON concentrations, depending on the covalent immobilisation method applied. This corresponds to a five orders of magnitude improvement in detectability of ZON relative to the previously developed enzyme-linked immonosorbent assay (ELISA) method. The selectivity of the immunosensor for ZON was demonstrated with structural analogues (α-zearalenol, α-zearalanol, and β-zearalanol) and structurally unrelated mycotoxins. The method was found to be applicable in maize extract using acetonitrile as the organic solvent, upon a dilution rate of 1:10,000 in buffer. Thus, the OWLS immunosensor method developed appears to be suitable for the quantitative determination of ZON in aqueous medium. The new technique can widen the range of sensoric detection methods of ZON for surveys in food and environmental safety assessment. Full article
(This article belongs to the Special Issue Rapid Detection of Mycotoxin Contamination)
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