Previous Issue

E-Mail Alert

Add your e-mail address to receive forthcoming issues of this journal:

Journal Browser

Journal Browser

Table of Contents

Toxins, Volume 11, Issue 6 (June 2019)

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
View options order results:
result details:
Displaying articles 1-45
Export citation of selected articles as:
Open AccessArticle
Toxin B Variants from Clostridium difficile Strains VPI 10463 and NAP1/027 Share Similar Substrate Profile and Cellular Intoxication Kinetics but Use Different Host Cell Entry Factors
Toxins 2019, 11(6), 348; https://doi.org/10.3390/toxins11060348 (registering DOI)
Received: 8 May 2019 / Accepted: 14 May 2019 / Published: 17 June 2019
PDF Full-text (2937 KB) | HTML Full-text | XML Full-text
Abstract
Clostridium difficile induces antibiotic-associated diarrhea due to the release of toxin A (TcdA) and toxin B (TcdB), the latter being its main virulence factor. The epidemic strain NAP1/027 has an increased virulence attributed to different factors. We compared cellular intoxication by TcdBNAP1 [...] Read more.
Clostridium difficile induces antibiotic-associated diarrhea due to the release of toxin A (TcdA) and toxin B (TcdB), the latter being its main virulence factor. The epidemic strain NAP1/027 has an increased virulence attributed to different factors. We compared cellular intoxication by TcdBNAP1 with that by the reference strain VPI 10463 (TcdBVPI). In a mouse ligated intestinal loop model, TcdBNAP1 induced higher neutrophil recruitment, cytokine release, and epithelial damage than TcdBVPI. Both toxins modified the same panel of small GTPases and exhibited similar in vitro autoprocessing kinetics. On the basis of sequence variations in the frizzled-binding domain (FBD), we reasoned that TcdBVPI and TcdBNAP1 might have different receptor specificities. To test this possibility, we used a TcdB from a NAP1 variant strain (TcdBNAP1v) unable to glucosylate RhoA but with the same receptor-binding domains as TcdBNAP1. Cells were preincubated with TcdBNAP1v to block cellular receptors, prior to intoxication with either TcdBVPI or TcdBNAP1. Preincubation with TcdBNAP1v blocked RhoA glucosylation by TcdBNAP1 but not by TcdBVPI, indicating that the toxins use different host factors for cell entry. This crucial difference might explain the increased biological activity of TcdBNAP1 in the intestine, representing a contributing factor for the increased virulence of the NAP1/027 strain. Full article
(This article belongs to the Special Issue Toxins Secretion and Translocation)
Figures

Figure 1

Open AccessReview
Repertoire of the Bacillus thuringiensis Virulence Factors Unrelated to Major Classes of Protein Toxins and Its Role in Specificity of Host-Pathogen Interactions
Toxins 2019, 11(6), 347; https://doi.org/10.3390/toxins11060347 (registering DOI)
Received: 29 April 2019 / Revised: 21 May 2019 / Accepted: 10 June 2019 / Published: 17 June 2019
PDF Full-text (647 KB) | HTML Full-text | XML Full-text
Abstract
Bacillus thuringiensis (Bt) is a Gram-positive soil bacteria that infects invertebrates, predominantly of Arthropoda phylum. Due to its immense host range Bt has become a leading producer of biopesticides applied both in biotechnology and agriculture. Cytotoxic effect of Bt, as [...] Read more.
Bacillus thuringiensis (Bt) is a Gram-positive soil bacteria that infects invertebrates, predominantly of Arthropoda phylum. Due to its immense host range Bt has become a leading producer of biopesticides applied both in biotechnology and agriculture. Cytotoxic effect of Bt, as well as its host specificity, are commonly attributed either to proteinaceous crystal parasporal toxins (Cry and Cyt) produced by bacteria in a stationary phase or to soluble toxins of Vip and Sip families secreted by vegetative cells. At the same time, numerous non-toxin virulence factors of Bt have been discovered, including metalloproteases, chitinases, aminopolyol antibiotics and nucleotide-mimicking moieties. These agents act at each stage of the B. thuringiensis invasion and contribute to cytotoxic properties of Bt strains enhancing toxin activity, ensuring host immune response evasion and participating in extracellular matrix degeneration. In this review we attempt to classify Bt virulence factors unrelated to major groups of protein toxins and discuss their putative role in the establishment of Bt specificity to various groups of insects. Full article
Figures

Figure 1

Open AccessCommunication
Recombinant Antibodies against Mycolactone
Toxins 2019, 11(6), 346; https://doi.org/10.3390/toxins11060346 (registering DOI)
Received: 28 March 2019 / Revised: 10 June 2019 / Accepted: 13 June 2019 / Published: 17 June 2019
PDF Full-text (2836 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In the past, it has proved challenging to generate antibodies against mycolactone, the primary lipidic toxin A of Mycobacterium ulcerans causing Buruli ulcer, due to its immunosuppressive properties. Here we show that in vitro display, comprising both phage and yeast display, can be [...] Read more.
In the past, it has proved challenging to generate antibodies against mycolactone, the primary lipidic toxin A of Mycobacterium ulcerans causing Buruli ulcer, due to its immunosuppressive properties. Here we show that in vitro display, comprising both phage and yeast display, can be used to select antibodies recognizing mycolactone from a large human naïve phage antibody library. Ten different antibodies were isolated, and hundreds more identified by next generation sequencing. These results indicate the value of in vitro display methods to generate antibodies against difficult antigenic targets such as toxins, which cannot be used for immunization unless inactivated by structural modification. The possibility to easily generate anti-mycolactone antibodies is an exciting prospect for the development of rapid and simple diagnostic/detection methods. Full article
(This article belongs to the Special Issue Mycolactone: Lipid-Like Immunosuppressive Toxin of Buruli Ulcer)
Figures

Figure 1

Open AccessArticle
Pharmacokinetics of Human Recombinant Anti-Botulinum Toxin Antibodies in Rats
Toxins 2019, 11(6), 345; https://doi.org/10.3390/toxins11060345 (registering DOI)
Received: 30 April 2019 / Revised: 2 June 2019 / Accepted: 3 June 2019 / Published: 17 June 2019
PDF Full-text (3663 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Botulinum neurotoxins (BoNT) are potential biothreat agents due to their high lethality, potency, and ease of distribution, thus the development of antitoxins is a high priority to the US government. This study examined pre-clinical pharmacokinetic studies in rats of four oligoclonal anti-BoNT mAb-based [...] Read more.
Botulinum neurotoxins (BoNT) are potential biothreat agents due to their high lethality, potency, and ease of distribution, thus the development of antitoxins is a high priority to the US government. This study examined pre-clinical pharmacokinetic studies in rats of four oligoclonal anti-BoNT mAb-based therapeutics (NTM-1631, NTM-1632, NTM-1633, NTM-1634) for five BoNT serotypes (A, B, E, C, and D). NTM-1631, NTM-1632, and NTM-1633 each consist of three IgG1 mAbs, each with a distinct human or humanized variable region which bind to distinct epitopes on BoNT serotype A, B, or E respectively. NTM-1634 consists of four human immunoglobulin G1 (IgG1) mAbs binding BoNT C/D mosaic toxins. The mechanism of these antitoxins requires that three antibodies simultaneously bind toxin to achieve rapid clearance. Rats (total 378) displayed no adverse clinical signs attributed to antibody treatment from any of the antitoxins. Pharmacokinetic evaluation demonstrated that the individual mAbs are slowly eliminated, exhibiting dose-dependent exposure and long elimination half-lives ranging from 6.5 days to 10 days. There were no consistent differences observed between males and females or among the individual antibodies in each formulation in half-life. Anti-drug antibodies (ADA) were observed, as expected for human antibodies administered to rats. The results presented were used to support the clinical investigation of antibody-based botulism antitoxins. Full article
(This article belongs to the Section Bacterial Toxins)
Figures

Figure 1

Open AccessArticle
Intramuscular Ricin Poisoning of Mice Leads to Widespread Damage in the Heart, Spleen, and Bone Marrow
Received: 2 May 2019 / Revised: 11 June 2019 / Accepted: 13 June 2019 / Published: 16 June 2019
Viewed by 153 | PDF Full-text (4151 KB) | Supplementary Files
Abstract
Ricin, a lethal toxin derived from castor oil beans, is a potential bio-threat due to its high availability and simplicity of preparation. Ricin is prepared according to simple recipes available on the internet, and was recently considered in terrorist, suicide, or homicide attempts [...] Read more.
Ricin, a lethal toxin derived from castor oil beans, is a potential bio-threat due to its high availability and simplicity of preparation. Ricin is prepared according to simple recipes available on the internet, and was recently considered in terrorist, suicide, or homicide attempts involving the parenteral route of exposure. In-depth study of the morbidity developing from parenteral ricin poisoning is mandatory for tailoring appropriate therapeutic measures to mitigate ricin toxicity in such instances. The present study applies various biochemical, hematological, histopathological, molecular, and functional approaches to broadly investigate the systemic effects of parenteral intoxication by a lethal dose of ricin in a murine model. Along with prompt coagulopathy, multi-organ hemorrhages, and thrombocytopenia, ricin induced profound morpho-pathological and functional damage in the spleen, bone marrow, and cardiovascular system. In the heart, diffuse hemorrhages, myocyte necrosis, collagen deposition, and induction in fibrinogen were observed. Severe functional impairment was manifested by marked thickening of the left ventricular wall, decreased ventricular volume, and a significant reduction in stroke volume and cardiac output. Unexpectedly, the differential severity of the ricin-induced damage did not correlate with the respective ricin-dependent catalytic activity measured in the various organs. These findings emphasize the complexity of ricin toxicity and stress the importance of developing novel therapeutic strategies that will combine not only anti-ricin specific therapy, but also will target ricin-induced indirect disturbances. Full article
(This article belongs to the collection Toxic and Pharmacological Effect of Plant Toxins)
Open AccessArticle
Novel Regulation of Alpha-Toxin and the Phenol-Soluble Modulins by Peptidyl-Prolyl cis/trans Isomerase Enzymes in Staphylococcus aureus
Received: 30 April 2019 / Revised: 10 June 2019 / Accepted: 12 June 2019 / Published: 16 June 2019
Viewed by 219 | PDF Full-text (1415 KB) | Supplementary Files
Abstract
Peptidyl-prolyl cis/trans isomerases (PPIases) are enzymes that catalyze the cis-to-trans isomerization around proline bonds, allowing proteins to fold into their correct confirmation. Previously, we identified two PPIase enzymes in Staphylococcus aureus (PpiB and PrsA) that are involved in the regulation of [...] Read more.
Peptidyl-prolyl cis/trans isomerases (PPIases) are enzymes that catalyze the cis-to-trans isomerization around proline bonds, allowing proteins to fold into their correct confirmation. Previously, we identified two PPIase enzymes in Staphylococcus aureus (PpiB and PrsA) that are involved in the regulation of virulence determinants and have shown that PpiB contributes to S. aureus virulence in a murine abscess model of infection. Here, we further examine the role of these PPIases in S. aureus virulence and, in particular, their regulation of hemolytic toxins. Using murine abscess and systemic models of infection, we show that a ppiB mutant in a USA300 background is attenuated for virulence but that a prsA mutant is not. Deletion of the ppiB gene leads to decreased bacterial survival in macrophages and nasal epithelial cells, while there is no significant difference when prsA is deleted. Analysis of culture supernatants reveals that a ppiB mutant strain has reduced levels of the phenol-soluble modulins and that both ppiB and prsA mutants have reduced alpha-toxin activity. Finally, we perform immunoprecipitation to identify cellular targets of PpiB and PrsA. Results suggest a novel role for PpiB in S. aureus protein secretion. Collectively, our results demonstrate that PpiB and PrsA influence S. aureus toxins via distinct mechanisms, and that PpiB but not PrsA contributes to disease. Full article
(This article belongs to the Special Issue Staphylococcus aureus Toxins)
Open AccessArticle
Occurrence of Mycotoxins in Swine Feeding from Spain
Received: 17 May 2019 / Revised: 7 June 2019 / Accepted: 13 June 2019 / Published: 15 June 2019
Viewed by 131 | PDF Full-text (842 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A survey including 228 pig feed samples from Spain has been developed, exploring the occurrence of 19 mycotoxins (aflatoxins B1, B2, G1 and G2, ochratoxin A, fumonisins B1 and B2, citrinin, zearalenone, deoxynivalenol, fusarenon X, sterigmatocystin, T-2 toxin, HT-2 toxin, enniatins A, A1, [...] Read more.
A survey including 228 pig feed samples from Spain has been developed, exploring the occurrence of 19 mycotoxins (aflatoxins B1, B2, G1 and G2, ochratoxin A, fumonisins B1 and B2, citrinin, zearalenone, deoxynivalenol, fusarenon X, sterigmatocystin, T-2 toxin, HT-2 toxin, enniatins A, A1, B and B2, and beauvericin). The samples were analysed by solid-liquid extraction followed by liquid chromatography coupled with fluorescence or mass spectrometry detection. Enniatin B was found in 100% of the samples (up to 1200 µg/kg) and beauvericin in more than 90%. Moreover, 40% of samples were contaminated with more than five mycotoxins. This high occurrence is insurmountable and surpasses all previous studies, probably due to the inclusion of emerging mycotoxins, scarcely explored. The majority of the samples (96.9%) were in accordance with EU regulations, which do not address emerging mycotoxins or co-occurrence. These results show that in order to ensure mycotoxin absence, emerging mycotoxins should always be considered. Full article
(This article belongs to the Special Issue Application of LC-MS/MS in the Mycotoxins Studies)
Figures

Figure 1

Open AccessArticle
Cytotoxicity, Genotoxicity and Disturbance of Cell Cycle in HepG2 Cells Exposed to OTA and BEA: Single and Combined Actions
Received: 21 March 2019 / Revised: 13 May 2019 / Accepted: 13 June 2019 / Published: 14 June 2019
Viewed by 148 | PDF Full-text (402 KB)
Abstract
Mycotoxins are produced by a number of fungal genera spp., for example, Aspergillus, Penicillium, Alternaria, Fusarium, and Claviceps. Beauvericin (BEA) and Ochratoxin A (OTA) are present in various cereal crops and processed grains. This goal of this study [...] Read more.
Mycotoxins are produced by a number of fungal genera spp., for example, Aspergillus, Penicillium, Alternaria, Fusarium, and Claviceps. Beauvericin (BEA) and Ochratoxin A (OTA) are present in various cereal crops and processed grains. This goal of this study was to determine their combination effect in HepG2 cells, presented for the first time. In this study, the type of interaction among BEA and OTA through an isobologram method, cell cycle disturbance by flow cytometry, and genotoxic potential by in vitro micronucleus (MN) assay following the TG 487 (OECD, 2016) of BEA and OTA individually and combined in HepG2 cells are presented. Cytotoxic concentration ranges studied by the MTT assay over 24, 48, and 72 h were from 0 to 25 µM for BEA and from 0 to 100 µM for OTA, while BEA + OTA combinations were at a 1:10 ratio from 3.4 to 27.5 µM. The toxicity observed for BEA was higher than for OTA at all times assayed; additive and synergistic effects were detected for their mixtures. Cell cycle arrest in the G0/G1 phase was detected for OTA and BEA + OTA treatments in HepG2 cells. Genotoxicity revealed significant effects for BEA, OTA, and in combinations underlining the importance of studying real exposure scenarios of chronic exposure to mycotoxins. Full article
(This article belongs to the Special Issue Toxicological Effects of Mycotoxin on Target Cells)
Open AccessArticle
Detection and Spatio-Temporal Distribution of Pinnatoxins in Shellfish from the Atlantic and Cantabrian Coasts of Spain
Received: 13 May 2019 / Revised: 7 June 2019 / Accepted: 13 June 2019 / Published: 14 June 2019
Viewed by 160 | PDF Full-text (846 KB) | Supplementary Files
Abstract
For the first time, pinnatoxins have been detected in shellfish from the Atlantic and Cantabrian coasts of Spain. High sensitivity LC-MS/MS systems were used to monitor all the currently known pinnatoxins (A–H). Pinnatoxin G (PnTX G) was the most prevalent toxin of the [...] Read more.
For the first time, pinnatoxins have been detected in shellfish from the Atlantic and Cantabrian coasts of Spain. High sensitivity LC-MS/MS systems were used to monitor all the currently known pinnatoxins (A–H). Pinnatoxin G (PnTX G) was the most prevalent toxin of the group, but its metabolite PnTX A has also been found at much lower levels. No trend in PnTX G concentration was found in the area, but a hotspot in the Ría de Camariñas has been identified. The maximum concentrations found did not exceed 15 µg·kg−1, being, in most cases, below 3 µg·kg−1. The highest concentrations were found in wild (intertidal) populations of mussels which attained much higher levels than raft-cultured ones, suggesting that the toxin-producer organisms preferentially develop in shallow areas. Other bivalve species had, in general, lower concentrations. The incidence of PnTX G followed a seasonal pattern in which the maximum concentrations took place in winter months. PnTX G was found to be partially esterified but the esterification percentage was not high (lower than 30%). Full article
(This article belongs to the Special Issue Dinoflagellate Toxins)
Figures

Graphical abstract

Open AccessArticle
Rational Design of Toxoid Vaccine Candidates for Staphylococcus aureus Leukocidin AB (LukAB)
Received: 1 May 2019 / Revised: 10 June 2019 / Accepted: 12 June 2019 / Published: 14 June 2019
Viewed by 135 | PDF Full-text (3599 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Staphylococcus aureus (SA) infections cause high mortality and morbidity in humans. Being central to its pathogenesis, S. aureus thwarts the host defense by secreting a myriad of virulence factors, including bicomponent, pore-forming leukotoxins. While all vaccine development efforts that aimed at achieving opsonophagocytic [...] Read more.
Staphylococcus aureus (SA) infections cause high mortality and morbidity in humans. Being central to its pathogenesis, S. aureus thwarts the host defense by secreting a myriad of virulence factors, including bicomponent, pore-forming leukotoxins. While all vaccine development efforts that aimed at achieving opsonophagocytic killing have failed, targeting virulence by toxoid vaccines represents a novel approach to preventing mortality and morbidity that are caused by SA. The recently discovered leukotoxin LukAB kills human phagocytes and monocytes and it is present in all known S. aureus clinical isolates. While using a structure-guided approach, we generated a library of mutations that targeted functional domains within the LukAB heterodimer to identify attenuated toxoids as potential vaccine candidates. The mutants were evaluated based on expression, solubility, yield, biophysical properties, cytotoxicity, and immunogenicity, and several fully attenuated LukAB toxoids that were capable of eliciting high neutralizing antibody titers were identified. Rabbit polyclonal antibodies against the lead toxoid candidate provided potent neutralization of LukAB. While the neutralization of LukAB alone was not sufficient to fully suppress leukotoxicity in supernatants of S. aureus USA300 isolates, a combination of antibodies against LukAB, α-toxin, and Panton-Valentine leukocidin completely neutralized the cytotoxicity of these strains. These data strongly support the inclusion of LukAB toxoids in a multivalent toxoid vaccine for the prevention of S. aureus disease. Full article
(This article belongs to the Special Issue Staphylococcus aureus Toxins)
Figures

Figure 1

Open AccessEditorial
Venom Toxins as Potential Targeted Therapies
Received: 9 May 2019 / Accepted: 10 June 2019 / Published: 13 June 2019
Viewed by 128 | PDF Full-text (193 KB) | HTML Full-text | XML Full-text
Abstract
Targeted therapy has been a very hot research topic in the last decade [...] Full article
(This article belongs to the Special Issue Venom and Toxin as Targeted Therapy)
Open AccessArticle
Cold Plasma Treatment as an Alternative for Ochratoxin a Detoxification and Inhibition of Mycotoxigenic Fungi in Roasted Coffee
Received: 23 May 2019 / Revised: 4 June 2019 / Accepted: 5 June 2019 / Published: 13 June 2019
Viewed by 127 | PDF Full-text (731 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Ochratoxin A (OTA) produced by mycotoxigenic fungi (Aspergillus and Penicillium spp.) is an extremely toxic and carcinogenic metabolite. The use of cold plasma to inhibit toxin-producing microorganisms in coffee could be an important alternative to avoid proliferation of mycotoxigenic fungi. Roasted coffee [...] Read more.
Ochratoxin A (OTA) produced by mycotoxigenic fungi (Aspergillus and Penicillium spp.) is an extremely toxic and carcinogenic metabolite. The use of cold plasma to inhibit toxin-producing microorganisms in coffee could be an important alternative to avoid proliferation of mycotoxigenic fungi. Roasted coffee samples were artificially inoculated with A. westerdijikiae, A. steynii, A. versicolor, and A. niger, and incubated at 27 °C over 21 days for OTA production. Samples were cold plasma treated at 30 W input power and 850 V output voltage with helium at 1.5 L/min flow. OTA production in coffee was analyzed by high performance liquid chromatography coupled to a mass spectrometer (HPLC-MS). After 6 min of treatment with cold plasma, fungi were completely inhibited (4 log reduction). Cold plasma reduces 50% of OTA content after 30 min of treatment. Toxicity was estimated for extracts of artificially contaminated roasted coffee samples using the brine shrimp (Artemia salina) lethality assay. Toxicity for untreated roasted coffee was shown to be “toxic”, while toxicity for cold plasma treated coffee was reduced to “slightly toxic”. These results suggested that cold plasma may be considered as an alternative method for the degradation and reduction of toxin production by mycotoxigenic fungi in the processing of foods and feedstuffs. Full article
(This article belongs to the Special Issue Novel Approaches to Minimising Mycotoxin Contamination)
Figures

Figure 1

Open AccessArticle
Rapid Purification of Endotoxin-Free RTX Toxins
Received: 14 May 2019 / Revised: 5 June 2019 / Accepted: 7 June 2019 / Published: 12 June 2019
Viewed by 194 | PDF Full-text (1593 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Cytolytic leukotoxins of the repeat in toxin (RTX) family are large proteins excreted by gram-negative bacterial pathogens through the type 1 secretion system (T1SS). Due to low yields and poor stability in cultures of the original pathogens, it is useful to purify recombinant [...] Read more.
Cytolytic leukotoxins of the repeat in toxin (RTX) family are large proteins excreted by gram-negative bacterial pathogens through the type 1 secretion system (T1SS). Due to low yields and poor stability in cultures of the original pathogens, it is useful to purify recombinant fatty-acylated RTX cytolysins from inclusion bodies produced in E. coli. Such preparations are, however, typically contaminated by high amounts of E. coli lipopolysaccharide (LPS or endotoxin). We report a simple procedure for purification of large amounts of biologically active and endotoxin-free RTX toxins. It is based on the common feature of RTX cytolysins that are T1SS-excreted as unfolded polypeptides and fold into a biologically active toxin only upon binding of calcium ions outside of the bacterial cell. Mimicking this process, the RTX proteins are solubilized from inclusion bodies with buffered 8 M urea, bound onto a suitable chromatographic medium under denaturing conditions and the contaminating LPS is removed through extensive on-column washes with buffers containing 6 to 8 M urea and 1% Triton X-100 or Triton X-114. Extensive on-column rinsing with 8 M urea buffer removes residual detergent and the eluted highly active RTX protein preparations then contain only trace amounts of LPS. The procedure is exemplified using four prototypic RTX cytolysins, the Bordetella pertussis CyaA and the hemolysins of Escherichia coli (HlyA), Kingella kingae (RtxA), and Actinobacillus pleuropneumoniae (ApxIA). Full article
(This article belongs to the Special Issue RTX Toxins)
Figures

Figure 1

Open AccessCommunication
Inhibition of Kv2.1 Potassium Channels by MiDCA1, A Pre-Synaptically Active PLA2-Type Toxin from Micrurus dumerilii carinicauda Coral Snake Venom
Received: 4 April 2019 / Revised: 13 May 2019 / Accepted: 14 May 2019 / Published: 12 June 2019
Viewed by 151 | PDF Full-text (1029 KB) | HTML Full-text | XML Full-text
Abstract
MiDCA1, a phospholipase A2 (PLA2) neurotoxin isolated from Micrurus dumerilii carinicauda coral snake venom, inhibited a major component of voltage-activated potassium (Kv) currents (41 ± 3% inhibition with 1 μM toxin) in mouse cultured dorsal root ganglion (DRG) neurons. In [...] Read more.
MiDCA1, a phospholipase A2 (PLA2) neurotoxin isolated from Micrurus dumerilii carinicauda coral snake venom, inhibited a major component of voltage-activated potassium (Kv) currents (41 ± 3% inhibition with 1 μM toxin) in mouse cultured dorsal root ganglion (DRG) neurons. In addition, the selective Kv2.1 channel blocker guangxitoxin (GxTx-1E) and MiDCA1 competitively inhibited the outward potassium current in DRG neurons. MiDCA1 (1 µM) reversibly inhibited the Kv2.1 current by 55 ± 8.9% in a Xenopus oocyte heterologous system. The toxin showed selectivity for Kv2.1 channels over all the other Kv channels tested in this study. We propose that Kv2.1 channel blockade by MiDCA1 underlies the toxin’s action on acetylcholine release at mammalian neuromuscular junctions. Full article
(This article belongs to the Special Issue Venoms and Ion Channels)
Figures

Figure 1

Open AccessReview
Rural Subsistence Maize Farming in South Africa: Risk Assessment and Intervention models for Reduction of Exposure to Fumonisin Mycotoxins
Received: 1 April 2019 / Revised: 27 April 2019 / Accepted: 14 May 2019 / Published: 12 June 2019
Viewed by 141 | PDF Full-text (639 KB) | HTML Full-text | XML Full-text
Abstract
Maize is a staple crop in rural subsistence regions of southern Africa, is mainly produced for direct household consumption and is often contaminated with high levels of mycotoxins. Chronic exposure to mycotoxins is a risk factor for human diseases as it is implicated [...] Read more.
Maize is a staple crop in rural subsistence regions of southern Africa, is mainly produced for direct household consumption and is often contaminated with high levels of mycotoxins. Chronic exposure to mycotoxins is a risk factor for human diseases as it is implicated in the development of cancer, neural tube defects as well as stunting in children. Although authorities may set maximum levels, these regulations are not effective in subsistence farming communities. As maize is consumed in large quantities, exposure to mycotoxins will surpass safe levels even where the contamination levels are below the regulated maximum levels. It is clear that the lowering of exposure in these communities requires an integrated approach. Detailed understanding of agricultural practices, mycotoxin occurrence, climate change/weather patterns, human exposure and risk are warranted to guide adequate intervention programmes. Risk communication and creating awareness in affected communities are also critical. A range of biologically based products for control of mycotoxigenic fungi and mycotoxins in maize have been developed and commercialised. Application of these methods is limited due to a lack of infrastructure and resources. Other challenges regarding integration and sustainability of technological and community-based mycotoxin reduction strategies include (i) food security, and (ii) the traditional use of mouldy maize. Full article
(This article belongs to the Special Issue Fungal Growth and Mycotoxins: Challenges for developing countries)
Figures

Figure 1

Open AccessArticle
Effects of Dietary Zearalenone on Oxidative Stress, Cell Apoptosis, and Tight Junction in the Intestine of Juvenile Grass Carp (Ctenopharyngodon idella)
Received: 20 April 2019 / Revised: 28 May 2019 / Accepted: 6 June 2019 / Published: 12 June 2019
Viewed by 149 | PDF Full-text (4870 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Zearalenone (ZEA) is a prevalent mycotoxin with high toxicity in animals. In order to study its effect on juvenile grass carp (Ctenopharyngodon idella), six diets supplemented with different levels of ZEA (0, 535, 1041, 1548, 2002, and 2507 μg/kg diet) for [...] Read more.
Zearalenone (ZEA) is a prevalent mycotoxin with high toxicity in animals. In order to study its effect on juvenile grass carp (Ctenopharyngodon idella), six diets supplemented with different levels of ZEA (0, 535, 1041, 1548, 2002, and 2507 μg/kg diet) for 10 weeks were studied to assess its toxicity on intestinal structural integrity and potential mechanisms of action. Our report firstly proved that ZEA led to growth retardation and body deformity, and impaired the intestinal structural integrity of juvenile grass carp, as revealed by the following findings: (1) ZEA accumulated in the intestine and caused histopathological lesions; (2) ZEA resulted in oxidative injury, apoptosis, and breached tight junctions in the fish intestine, which were probably associated with Nuclear factor-erythroid 2-related factor 2 (Nrf2), p38 mitogen activated protein kinases (p38MAPK), and myosin light chain kinase (MLCK) signaling pathways, respectively. ZEA had no influence on the antioxidant gene levels of Kelch-like ECH associating protein 1 (Keap1)b (rather than Keap1a), glutathione-S-transferase (GST)P1, GSTP2 (not in the distal intestine (DI)), tight junctions occludin, claudin-c (not in the proximal intestine (PI)), or claudin-3c (not in the mid intestine (MI) or DI). Full article
(This article belongs to the Special Issue Fungal Infestations in Humans, Animals, Crops)
Figures

Figure 1

Open AccessReview
The Role of Streptococcal and Staphylococcal Exotoxins and Proteases in Human Necrotizing Soft Tissue Infections
Received: 20 May 2019 / Revised: 4 June 2019 / Accepted: 10 June 2019 / Published: 11 June 2019
Viewed by 182 | PDF Full-text (1731 KB) | HTML Full-text | XML Full-text
Abstract
Necrotizing soft tissue infections (NSTIs) are critical clinical conditions characterized by extensive necrosis of any layer of the soft tissue and systemic toxicity. Group A streptococci (GAS) and Staphylococcus aureus are two major pathogens associated with monomicrobial NSTIs. In the tissue environment, both [...] Read more.
Necrotizing soft tissue infections (NSTIs) are critical clinical conditions characterized by extensive necrosis of any layer of the soft tissue and systemic toxicity. Group A streptococci (GAS) and Staphylococcus aureus are two major pathogens associated with monomicrobial NSTIs. In the tissue environment, both Gram-positive bacteria secrete a variety of molecules, including pore-forming exotoxins, superantigens, and proteases with cytolytic and immunomodulatory functions. The present review summarizes the current knowledge about streptococcal and staphylococcal toxins in NSTIs with a special focus on their contribution to disease progression, tissue pathology, and immune evasion strategies. Full article
Figures

Figure 1

Open AccessArticle
Occurrence of Tetrodotoxin in Bivalves and Gastropods from Harvesting Areas and Other Natural Spaces in Spain
Received: 30 April 2019 / Revised: 5 June 2019 / Accepted: 7 June 2019 / Published: 11 June 2019
Viewed by 187 | PDF Full-text (674 KB) | HTML Full-text | XML Full-text
Abstract
Tetrodotoxin (TTX) is a potent neurotoxin that is receiving increasing interest in the European Union because it has been found in different fishery products (fish, bivalves and gastropods) captured in European waters. Since available information is scarce, further analytical data regarding the incidence [...] Read more.
Tetrodotoxin (TTX) is a potent neurotoxin that is receiving increasing interest in the European Union because it has been found in different fishery products (fish, bivalves and gastropods) captured in European waters. Since available information is scarce, further analytical data regarding the incidence of this toxin in European fishery products is needed in order to perform an appropriate risk assessment devoted to protecting consumers’ health. Hence, samples of bivalves and gastropods were collected at different points of the Spanish coast and analyzed by high-performance hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) to evaluate the presence of TTX. None of the analyzed samples showed TTX above an internal threshold of 10 µg/kg or even showed a peak under it. Our results on TTX occurrence obtained in bivalve molluscs and gastropods did not show, at least in the studied areas, a risk for public health. However, taking into account previous positive results obtained by other research groups, and since we did not detect TTX in our samples, a more completed study increasing sampling frequency is needed to ensure proper risk evaluation towards the food safety of these products. Full article
(This article belongs to the Special Issue Tetrodotoxins)
Figures

Figure 1

Open AccessArticle
Application of Zearalenone (ZEN)-Detoxifying Bacillus in Animal Feed Decontamination through Fermentation
Received: 27 May 2019 / Revised: 5 June 2019 / Accepted: 6 June 2019 / Published: 8 June 2019
Viewed by 297 | PDF Full-text (678 KB) | HTML Full-text | XML Full-text
Abstract
Zearalenone (ZEN) is an estrogenic mycotoxin which can cause loss in animal production. The aim of this study was to screen Bacillus strains for their ZEN detoxification capability and use a fermentation process to validate their potential application in the feed industry. In [...] Read more.
Zearalenone (ZEN) is an estrogenic mycotoxin which can cause loss in animal production. The aim of this study was to screen Bacillus strains for their ZEN detoxification capability and use a fermentation process to validate their potential application in the feed industry. In the high-level ZEN-contaminated maize (5 mg·kg−1) fermentation test, B2 strain exhibited the highest detoxification rate, removing 56% of the ZEN. However, B2 strain was not the strain with the highest ZEN detoxification in the culturing media. When B2 grew in TSB medium with ZEN, it had higher bacterial numbers, lactic acid, acetic acid, total volatile fatty acids, and ammonia nitrogen. The ZEN-contaminated maize fermented by B2 strain had better fermentation characteristics (lactic acid > 110 mmol·L−1; acetic acid < 20 mmol·L−1; pH < 4.5) than ZEN-free maize. Furthermore, B2 also had detoxification capabilities toward aflatoxins B1, deoxynivalenol, fumonisin B1, and T2 toxin. Our study demonstrated differences in screening outcome between bacterial culturing conditions and the maize fermentation process. This is important for the feed industry to consider when choosing a proper method to screen candidate isolates for the pretreatment of ZEN-contaminated maize. It appears that using the fermentation process to address the ZEN-contaminated maize problem in animal feed is a reliable choice. Full article
(This article belongs to the Special Issue Novel Approaches to Minimising Mycotoxin Contamination)
Figures

Figure 1

Open AccessArticle
Occurrence of the Ochratoxin A Degradation Product 2′R-Ochratoxin A in Coffee and Other Food: An Update
Received: 18 April 2019 / Revised: 16 May 2019 / Accepted: 3 June 2019 / Published: 8 June 2019
Viewed by 322 | PDF Full-text (933 KB) | HTML Full-text | XML Full-text
Abstract
Food raw materials can contain the mycotoxin ochratoxin A (OTA). Thermal processing of these materials may result in decreased OTA levels but also in the formation of the thermal isomerization product 2′R-ochratoxin A (2′R-OTA). So far, only 2′R-OTA levels reported from 15 coffee [...] Read more.
Food raw materials can contain the mycotoxin ochratoxin A (OTA). Thermal processing of these materials may result in decreased OTA levels but also in the formation of the thermal isomerization product 2′R-ochratoxin A (2′R-OTA). So far, only 2′R-OTA levels reported from 15 coffee samples in 2008 are known, which is little when compared to the importance of coffee as a food and trading good. Herein, we present results from a set of model experiments studying the effect of temperatures between 120 °C and 270 °C on the isomerization of OTA to 2′R-OTA. It is shown that isomerization of OTA starts at temperatures as low as 120 °C. At 210 °C and above, the formation of 25% 2′R-OTA is observed in less than one minute. Furthermore, 51 coffee samples from France, Germany, and Guatemala were analyzed by HPLC-MS/MS for the presence of OTA and 2′R-OTA. OTA was quantified in 96% of the samples, while 2′R-OTA was quantifiable in 35% of the samples. The highest OTA and 2′R-OTA levels of 28.4 µg/kg and 3.9 µg/kg, respectively, were detected in coffee from Guatemala. The OTA:2′R-OTA ratio in the samples ranged between 2.5:1 and 10:1 and was on average 5.5:1. Besides coffee, 2′R-OTA was also for the first time detected in a bread sample and malt coffee powder. Full article
Figures

Figure 1

Open AccessReview
Fumonisins: Impact on Agriculture, Food, and Human Health and their Management Strategies
Received: 4 May 2019 / Revised: 4 June 2019 / Accepted: 4 June 2019 / Published: 7 June 2019
Viewed by 499 | PDF Full-text (484 KB) | HTML Full-text | XML Full-text
Abstract
The fumonisins producing fungi, Fusarium spp., are ubiquitous in nature and contaminate several food matrices that pose detrimental health hazards on humans as well as on animals. This has necessitated profound research for the control and management of the toxins to guarantee better [...] Read more.
The fumonisins producing fungi, Fusarium spp., are ubiquitous in nature and contaminate several food matrices that pose detrimental health hazards on humans as well as on animals. This has necessitated profound research for the control and management of the toxins to guarantee better health of consumers. This review highlights the chemistry and biosynthesis process of the fumonisins, their occurrence, effect on agriculture and food, along with their associated health issues. In addition, the focus has been put on the detection and management of fumonisins to ensure safe and healthy food. The main focus of the review is to provide insights to the readers regarding their health-associated food consumption and possible outbreaks. Furthermore, the consumers’ knowledge and an attempt will ensure food safety and security and the farmers’ knowledge for healthy agricultural practices, processing, and management, important to reduce the mycotoxin outbreaks due to fumonisins. Full article
(This article belongs to the Special Issue Mycotoxins in Feed and Food Chain: Present Status and Future Concerns)
Figures

Graphical abstract

Open AccessArticle
Effects of Disruption of Five FUM Genes on Fumonisin Biosynthesis and Pathogenicity in Fusarium proliferatum
Received: 7 May 2019 / Revised: 6 June 2019 / Accepted: 6 June 2019 / Published: 7 June 2019
Viewed by 180 | PDF Full-text (11715 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The mycotoxin fumonisin is known to be harmful to humans and animals, and thus it is desirable to reduce fumonisin content in crop products. We explored the functions of several genes that function in fumonisin biosynthesis (FUM1, FUM6, FUM8, [...] Read more.
The mycotoxin fumonisin is known to be harmful to humans and animals, and thus it is desirable to reduce fumonisin content in crop products. We explored the functions of several genes that function in fumonisin biosynthesis (FUM1, FUM6, FUM8, FUM19, and FUM21) in Fusarium proliferatum and found that deletion of FUM1, FUM6, FUM8, or FUM21 results in a severe reduction in fumonisin biosynthesis, while loss of FUM19 does not. In addition, fumonisin-deficient strains display significantly decreased pathogenicity. Co-cultivation of the ΔFUM1, ΔFUM6, ΔFUM8, and ΔFUM19 mutants restores fumonisin synthesis. However, co-cultivation was unable to restore fumonisin synthesis in the ΔFUM21 strain. The relative expression levels of three key FUM genes (FUM1, FUM6, and FUM8) differed significantly in each mutant strain; notably, the expression levels of these three genes were significantly down-regulated in the ΔFUM21 strain. Taken together, our results demonstrate that FUM1, FUM6, FUM8, and FUM21 are essential for fumonisin synthesis, and FUM19 is non-essential. Partial mutants lost the ability to synthesize fumonisin, the co-culture of the mutants was able to restore fumonisin biosynthesis. While the pathogenicity of F. proliferatum is affected by many factors, inhibition of the synthesis of the mycotoxin fumonisin will weaken the pathogenicity of rice spikelet rot disease (RSRD). Full article
(This article belongs to the Section Mycotoxins)
Figures

Figure 1

Open AccessArticle
Prevalence and Genetic Diversity of Toxin Genes in Clinical Isolates of Clostridium perfringens: Coexistence of Alpha-Toxin Variant and Binary Enterotoxin Genes (bec/cpile)
Received: 13 May 2019 / Revised: 30 May 2019 / Accepted: 4 June 2019 / Published: 6 June 2019
Viewed by 344 | PDF Full-text (1237 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Clostridium perfringens (C. perfringens) is responsible for food-borne gastroenteritis and other infectious diseases, and toxins produced by this bacterium play a key role in pathogenesis. Although various toxins have been described for C. perfringens isolates from humans and animals, prevalence of [...] Read more.
Clostridium perfringens (C. perfringens) is responsible for food-borne gastroenteritis and other infectious diseases, and toxins produced by this bacterium play a key role in pathogenesis. Although various toxins have been described for C. perfringens isolates from humans and animals, prevalence of individual toxins among clinical isolates has not yet been well explored. In the present study, a total of 798 C. perfringens clinical isolates were investigated for prevalence of eight toxin genes and their genetic diversity by PCR, nucleotide sequencing, and phylogenetic analysis. Besides the alpha-toxin gene (plc) present in all the isolates, the most common toxin gene was cpe (enterotoxin) (34.2%), followed by cpb2 (beta2 toxin) (1.4%), netB (NetB) (0.3%), and bec/cpile (binary enterotoxin BEC/CPILE) (0.1%), while beta-, epsilon-, and iota-toxin genes were not detected. Genetic analysis of toxin genes indicated a high level of conservation of plc, cpe, and netB. In contrast, cpb2 was revealed to be considerably divergent, containing at least two lineages. Alpha-toxin among 46 isolates was classified into ten sequence types, among which common types were distinct from those reported for avian isolates. A single isolate with bec/cpile harbored a plc variant containing an insertion of 834-bp sequence, suggesting its putative origin from chickens. Full article
Figures

Figure 1

Open AccessArticle
Structure and Activity of a Cytosolic Ribosome-Inactivating Protein from Rice
Received: 8 May 2019 / Revised: 30 May 2019 / Accepted: 4 June 2019 / Published: 6 June 2019
Viewed by 225 | PDF Full-text (5641 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Ribosome-inactivating proteins (RIPs) are cytotoxic enzymes that inhibit protein translation by depurinating ribosomal RNA. Although most plant RIPs are synthesized with leader sequences that sequester them away from the host ribosomes, several RIPs from cereals lack these signal peptides and therefore probably reside [...] Read more.
Ribosome-inactivating proteins (RIPs) are cytotoxic enzymes that inhibit protein translation by depurinating ribosomal RNA. Although most plant RIPs are synthesized with leader sequences that sequester them away from the host ribosomes, several RIPs from cereals lack these signal peptides and therefore probably reside in the cytosol near the plant ribosomes. More than 30 RIP genes have been identified in the rice (Oryza sativa spp. japonica) genome, many of them lacking a signal peptide. This paper focuses on a presumed cytosolic type-1 RIP from rice, referred to as OsRIP1. Using 3D modeling it is shown that OsRIP1 structurally resembles other cereal RIPs and has an active site that meets the requirements for activity. Furthermore, localization studies indicate that OsRIP1-eGFP fusion proteins reside in the nucleocytoplasmic space when expressed in epidermal cells of Nicotiana benthamiana or Arabidopsis thaliana suspension cells. Finally, OsRIP1 was recombinantly produced in Escherichia coli and was demonstrated to possess catalytic activity. Interestingly, this recombinant RIP inactivates wheat ribosomes far less efficiently than rabbit ribosomes in an in vitro system. These findings raise some interesting questions concerning the mode of action and physiological role of OsRIP1. This is the first time a RIP from rice is investigated at protein level and is shown to possess biological activity. Full article
(This article belongs to the Special Issue Ribosome inactivating proteins (RIPs))
Figures

Figure 1

Open AccessReview
Ricin: An Ancient Story for a Timeless Plant Toxin
Received: 15 April 2019 / Revised: 3 June 2019 / Accepted: 5 June 2019 / Published: 6 June 2019
Viewed by 259 | PDF Full-text (11729 KB) | HTML Full-text | XML Full-text
Abstract
The castor plant (Ricinus communis L.) has been known since time immemorial in traditional medicine in the pharmacopeia of Mediterranean and eastern ancient cultures. Moreover, it is still used in folk medicine worldwide. Castor bean has been mainly recommended as anti-inflammatory, anthelmintic, [...] Read more.
The castor plant (Ricinus communis L.) has been known since time immemorial in traditional medicine in the pharmacopeia of Mediterranean and eastern ancient cultures. Moreover, it is still used in folk medicine worldwide. Castor bean has been mainly recommended as anti-inflammatory, anthelmintic, anti-bacterial, laxative, abortifacient, for wounds, ulcers, and many other indications. Many cases of human intoxication occurred accidentally or voluntarily with the ingestion of castor seeds or derivatives. Ricinus toxicity depends on several molecules, among them the most important is ricin, a protein belonging to the family of ribosome-inactivating proteins. Ricin is the most studied of this category of proteins and it is also known to the general public, having been used for several biocrimes. This manuscript intends to give the reader an overview of ricin, focusing on the historical path to the current knowledge on this protein. The main steps of ricin research are here reported, with particular regard to its enzymatic activity, structure, and cytotoxicity. Moreover, we discuss ricin toxicity for animals and humans, as well as the relation between bioterrorism and ricin and its impact on environmental toxicity. Ricin has also been used to develop immunotoxins for the elimination of unwanted cells, mainly cancer cells; some of these immunoconjugates gave promising results in clinical trials but also showed critical limitation. Full article
(This article belongs to the Special Issue Ricin Toxins)
Figures

Graphical abstract

Open AccessArticle
A Gold Growth-Based Plasmonic ELISA for the Sensitive Detection of Fumonisin B1 in Maize
Received: 24 April 2019 / Revised: 31 May 2019 / Accepted: 4 June 2019 / Published: 5 June 2019
Viewed by 219 | PDF Full-text (758 KB) | Supplementary Files
Abstract
In this paper, a highly sensitive plasmonic enzyme-linked immunosorbent assay (pELISA) was developed for the naked-eye detection of fumonisin B1 (FB1). Glucose oxidase (GOx) was used as an alternative to horseradish peroxidase as the carrier of the competing antigen. GOx [...] Read more.
In this paper, a highly sensitive plasmonic enzyme-linked immunosorbent assay (pELISA) was developed for the naked-eye detection of fumonisin B1 (FB1). Glucose oxidase (GOx) was used as an alternative to horseradish peroxidase as the carrier of the competing antigen. GOx catalyzed the oxidation of glucose to produce hydrogen peroxide, which acted as a reducing agent to reduce Au3+ to Au on the surface of gold seeds (5 nm), This reaction led to a color change in the solution from colorless to purple, which was observable to the naked eye. Various parameters that could influence the detection performance of pELISA were investigated. The developed method exhibited a considerably high sensitivity for FB1 qualitative naked-eye detection, with a visible cut-off limit of 1.25 ng/mL. Moreover, the proposed pELISA showed a good linear range of 0.31–10 ng/mL with a half maximal inhibitory concentration (IC50) of 1.86 ng/mL, which was approximately 13-fold lower than that of a horseradish peroxidase- (HRP)-based conventional ELISA. Meanwhile, the proposed method was highly specific and accurate. In summary, the new pELISA exhibited acceptable accuracy and precision for sensitive naked-eye detection of FB1 in maize samples and can be applied for the detection of other chemical contaminants. Full article
(This article belongs to the Special Issue Advanced Methods for Mycotoxins Detection)
Open AccessArticle
Identification of the Fungal Pathogens of Postharvest Disease on Peach Fruits and the Control Mechanisms of Bacillus subtilis JK-14
Received: 23 April 2019 / Revised: 29 May 2019 / Accepted: 1 June 2019 / Published: 5 June 2019
Viewed by 257 | PDF Full-text (1570 KB) | HTML Full-text | XML Full-text
Abstract
Postharvest fungal disease is one of the significant factors that limits the storage period and marketing life of peaches, and even result in serious economic losses worldwide. Biological control using microbial antagonists has been explored as an alternative approach for the management of [...] Read more.
Postharvest fungal disease is one of the significant factors that limits the storage period and marketing life of peaches, and even result in serious economic losses worldwide. Biological control using microbial antagonists has been explored as an alternative approach for the management of postharvest disease of fruits. However, there is little information available regarding to the identification the fungal pathogen species that cause the postharvest peach diseases and the potential and mechanisms of using the Bacillus subtilis JK-14 to control postharvest peach diseases. In the present study, a total of six fungal isolates were isolated from peach fruits, and the isolates of Alternaria tenuis and Botrytis cinerea exhibited the highest pathogenicity and virulence on the host of mature peaches. In the culture plates, the strain of B. subtilis JK-14 showed the significant antagonistic activity against the growth of A. tenuis and B. cinerea with the inhibitory rates of 81.32% and 83.45% at 5 days after incubation, respectively. Peach fruits treated with different formulations of B. subtilis JK-14 significantly reduced the mean disease incidences and lesion diameters of A. tenuis and B. cinerea. The greatest mean percent reduction of the disease incidences (81.99% and 71.34%) and lesion diameters (82.80% and 73.57%) of A. tenuis and B. cinerea were obtained at the concentration of 1 × 107 CFU mL−1 (colony forming unit, CFU). Treatment with the strain of B. subtilis JK-14 effectively enhanced the activity of the antioxidant enzymes-superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in A. tenuis and B. cinerea inoculated peach fruits. As such, the average activities of SOD, POD and CAT were increased by 36.56%, 17.63% and 20.35%, respectively, compared to the sterile water treatment. Our results indicate that the isolates of A. tenuis and B. cinerea are the main pathogens that cause the postharvest peach diseases, and the strain of B. subtilis JK-14 can be considered as an environmentally-safe biological control agent for the management of postharvest fruits diseases. We propose the possible mechanisms of the strain of B. subtilis JK-14 in controlling of postharvest peach diseases. Full article
(This article belongs to the collection Understanding Mycotoxin Occurrence in Food and Feed Chains)
Figures

Figure 1

Open AccessReview
Exploring the Role of Staphylococcus Aureus Toxins in Atopic Dermatitis
Received: 8 May 2019 / Revised: 28 May 2019 / Accepted: 30 May 2019 / Published: 5 June 2019
Viewed by 196 | PDF Full-text (857 KB) | HTML Full-text | XML Full-text
Abstract
Atopic dermatitis (AD) is a chronic and inflammatory skin disease with intense pruritus and xerosis. AD pathogenesis is multifactorial, involving genetic, environmental, and immunological factors, including the participation of Staphylococcus aureus. This bacterium colonizes up to 30–100% of AD skin and its [...] Read more.
Atopic dermatitis (AD) is a chronic and inflammatory skin disease with intense pruritus and xerosis. AD pathogenesis is multifactorial, involving genetic, environmental, and immunological factors, including the participation of Staphylococcus aureus. This bacterium colonizes up to 30–100% of AD skin and its virulence factors are responsible for its pathogenicity and antimicrobial survival. This is a concise review of S. aureus superantigen-activated signaling pathways, highlighting their involvement in AD pathogenesis, with an emphasis on skin barrier disruption, innate and adaptive immunity dysfunction, and microbiome alterations. A better understanding of the combined mechanisms of AD pathogenesis may enhance the development of future targeted therapies for this complex disease. Full article
(This article belongs to the Special Issue Staphylococcus aureus Toxins)
Figures

Figure 1

Open AccessArticle
The Relationship Analysis on Corn Stalk Rot and Ear Rot According to Fusarium Species and Fumonisin Contamination in Kernels
Received: 12 April 2019 / Revised: 28 May 2019 / Accepted: 4 June 2019 / Published: 5 June 2019
Viewed by 179 | PDF Full-text (4927 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Fusarium diseases, including corn root rot, sheath rot, stalk rot, and ear rot are frequently occurring in maize producing areas of China. Fusarium stalk rot and ear rot are the most serious diseases and often occur at the same time, but it is [...] Read more.
Fusarium diseases, including corn root rot, sheath rot, stalk rot, and ear rot are frequently occurring in maize producing areas of China. Fusarium stalk rot and ear rot are the most serious diseases and often occur at the same time, but it is unclear whether there is a correlation between Fusarium composition and disease occurrence. This study was conducted to clarify the relationship between the two diseases. A total of 49 corn stalk rot samples were collected from 15 regions of eight provinces in China from 2016 to 2018. The pathogens were isolated and identified separately from stalks, ear stems, and kernels. The contents of the fumonisins (FB1 and FB2) were detected in kernels. The results showed that the main Fusarium species were found in corn kernels, ear stems and stalks at the same time. The results showed that 1201 strains of Fusarium verticillioides, 668 strains of Fusarium oxysporum, 574 strains of Fusarium graminearum species complex (FGSC), 318 strains of Fusarium equiseti, 95 strains of Fusarium proliferatum, and 40 strains of Fusarium subglutinans were isolated from 1470 corn kernels, 245 ear stems, and 1225 stalks randomly selected from 49 samples. The contamination rate of fumonisins in the 49 samples was 57.1% with an average content of 1.9 μg/g, of which four samples exhibited higher levels as set by the European Commission (4.0 μg/g). These results provide a certain association between stalk rot and ear rot and lay a foundation to study the relationships among Fusarium maize diseases. Full article
(This article belongs to the Special Issue Fungal Infestations in Humans, Animals, Crops)
Figures

Figure 1

Open AccessArticle
Deoxynivalenol-3-Glucoside Content Is Highly Associated with Deoxynivalenol Levels in Two-Row Barley Genotypes of Importance to Canadian Barley Breeding Programs
Received: 17 April 2019 / Revised: 15 May 2019 / Accepted: 24 May 2019 / Published: 5 June 2019
Viewed by 370 | PDF Full-text (1198 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Barley (Hordeum vulgare L.) is a multipurpose crop that can be harvested as grain or cut prior to maturity for use as forage. Fusarium head blight (FHB) is a devastating disease of barley that reduces quality of grain. FHB can also result [...] Read more.
Barley (Hordeum vulgare L.) is a multipurpose crop that can be harvested as grain or cut prior to maturity for use as forage. Fusarium head blight (FHB) is a devastating disease of barley that reduces quality of grain. FHB can also result in the accumulation of mycotoxins such as deoxynivalenol (DON). Breeding FHB resistant varieties has been a long-term goal of many barley-producing countries, including Canada. While the genetic basis of DON detoxification via production of less-phytotoxic conjugates such as DON-3-glucoside (DON3G) is well documented in barley, little information exists in reference to varietal response. Over two years, 16 spring, two-row barley genotypes, of importance to western Canadian barley breeding programs, were grown as short-rows and inoculated following spike emergence with a Fusarium graminearum conidia suspension. Half of the plots were harvested at soft dough stage and then dissected into rachis and grain components, whereas the remainder was harvested at maturity. Multiple Fusarium-mycotoxins were assayed using liquid chromatography-mass spectrometry. Mycotoxin content was elevated at the earlier harvest point, especially in the rachis tissue. DON3G constituted a significant percentage (26%) of total trichothecene content and thus its co-occurrence with DON should be considered by barley industries. DON3G was highly correlated with DON and 3-acetyl-deoxynivalenol (3ADON). The ratio of D3G/DON exhibited consistency across genotypes, however more-resistant genotypes were characterized by a higher ratio at the soft-dough stage followed by a decrease at maturity. Plant breeding practices that use DON content as a biomarker for resistance would likely result in the development of barley cultivars with lower total DON-like compounds. Full article
Figures

Figure 1

Toxins EISSN 2072-6651 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top