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Toxins
Volume 9
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Toxins, Volume 9, Issue 8 (August 2017) – 22 articles

Cover Story (view full-size image): Fibrinogen is central to a myriad of clotting diseases and disorders including stroke. This article reports the discovery in the venoms of many varanid lizards novel enzymes which selectively cleave the different chains of fibrinogen to produce anticoagulant states. Such selective cleavage in snake venom enzumes, such as Ancrod/Arvin, has led to their therapeutic use. The unique forms discovered in lizard venoms thus have drug design and development potential. View Paper here
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1939 KiB  
Review
The Myriad Properties of Pasteurella multocida Lipopolysaccharide
by Marina Harper and John Dallas Boyce
Toxins 2017, 9(8), 254; https://doi.org/10.3390/toxins9080254 - 21 Aug 2017
Cited by 44 | Viewed by 7987
Abstract
Pasteurella multocida is a heterogeneous species that is a primary pathogen of many different vertebrates. This Gram-negative bacterium can cause a range of diseases, including fowl cholera in birds, haemorrhagic septicaemia in ungulates, atrophic rhinitis in swine, and lower respiratory tract infections in [...] Read more.
Pasteurella multocida is a heterogeneous species that is a primary pathogen of many different vertebrates. This Gram-negative bacterium can cause a range of diseases, including fowl cholera in birds, haemorrhagic septicaemia in ungulates, atrophic rhinitis in swine, and lower respiratory tract infections in cattle and pigs. One of the primary virulence factors of P. multocida is lipopolysaccharide (LPS). Recent work has shown that this crucial surface molecule shows significant structural variability across different P. multocida strains, with many producing LPS structures that are highly similar to the carbohydrate component of host glycoproteins. It is likely that this LPS mimicry of host molecules plays a major role in the survival of P. multocida in certain host niches. P. multocida LPS also plays a significant role in resisting the action of chicken cathelicidins, and is a strong stimulator of host immune responses. The inflammatory response to the endotoxic lipid A component is a major contributor to the pathogenesis of certain infections. Recent work has shown that vaccines containing killed bacteria give protection only against other strains with identical, or nearly identical, surface LPS structures. Conversely, live attenuated vaccines give protection that is broadly protective, and their efficacy is independent of LPS structure. Full article
(This article belongs to the Special Issue Pasteurella multocida and Its Virulence Factors)
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Article
Efficacy of Repeated Botulinum Toxin Type A Injections for Spastic Equinus in Children with Cerebral Palsy—A Secondary Analysis of the Randomized Clinical Trial
by Bo Young Hong, Hyun Jung Chang, Sang-Jee Lee, Soyoung Lee, Joo Hyun Park and Jeong-Yi Kwon
Toxins 2017, 9(8), 253; https://doi.org/10.3390/toxins9080253 - 21 Aug 2017
Cited by 18 | Viewed by 4918
Abstract
Botulinum toxin A is considered an important tool to control spasticity in children with cerebral palsy. Several factors are known to affect the efficacy of botulinum toxin, such as dosage, appropriate muscle selection and application, age, and accompanying therapy. A multicenter, double-blind, randomized, [...] Read more.
Botulinum toxin A is considered an important tool to control spasticity in children with cerebral palsy. Several factors are known to affect the efficacy of botulinum toxin, such as dosage, appropriate muscle selection and application, age, and accompanying therapy. A multicenter, double-blind, randomized, prospective phase III clinical trial of botulinum toxin A for the treatment of dynamic equinus in 144 children with cerebral palsy was performed to compare the efficacies of letibotulinumtoxin A and onabotulinumtoxin A. Secondary analyses were performed to evaluate factors that affected the outcome, focusing on the number of times injections were repeated. Effectiveness was defined as a change of 2 or more in the physician’s rating scale. Multivariate regression analyses were performed with multiple variables. The first injection of botulinum toxin A significantly improved D subscale of Gross Motor Function Measure-88 scores at 3 months compared to repeated injections (p < 0.05). After 6 months, patients who had one injection or none before the study showed significantly better outcomes than those who had more than one injection in terms of observational gait scores. Full article
(This article belongs to the Section Bacterial Toxins)
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Article
Efficacy and Safety of Letibotulinum Toxin A for the Treatment of Dynamic Equinus Foot Deformity in Children with Cerebral Palsy: A Randomized Controlled Trial
by Hyun Jung Chang, Bo Young Hong, Sang-Jee Lee, Soyoung Lee, Joo Hyun Park and Jeong-Yi Kwon
Toxins 2017, 9(8), 252; https://doi.org/10.3390/toxins9080252 - 18 Aug 2017
Cited by 13 | Viewed by 5616
Abstract
The objective of this clinical trial was to compare the efficacy and safety of letibotulinum toxin A and onabotulinum toxin A for improving dynamic equinus foot deformity in children with cerebral palsy (CP). In total, 144 children with spastic CP who had dynamic [...] Read more.
The objective of this clinical trial was to compare the efficacy and safety of letibotulinum toxin A and onabotulinum toxin A for improving dynamic equinus foot deformity in children with cerebral palsy (CP). In total, 144 children with spastic CP who had dynamic equinus foot deformity were assigned randomly to the Botulax group (injection of letibotulinum toxin A) or the Botox group (injection of onabotulinum toxin A). The Physician’s Rating Scale (PRS), ankle plantar flexor spasticity using the Modified Tardieu Scale, the Gross Motor Function Measure (GMFM)-88, and the GMFM-66 were completed before injection and at 6, 12, and 24 weeks after injection. The PRS responder rate was 60.27% in the Botulax group and 61.43% in the Botox group at 12 weeks after treatment, and the lower limit of the 95% confidence interval for the between-group difference in responder rates was −17.16%, higher than the non-inferiority margin of −24.00%. The clinical efficacy and the safety profiles of the groups did not significantly differ. The results suggest that injection of letibotulinum toxin A is as effective and safe as that of onabotulinum toxin A for the treatment of dynamic equinus foot deformity in children with spastic CP. Full article
(This article belongs to the Special Issue Botulinum Neurotoxins Antibody and Vaccine)
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Review
Studies on the Presence of Mycotoxins in Biological Samples: An Overview
by Laura Escrivá, Guillermina Font, Lara Manyes and Houda Berrada
Toxins 2017, 9(8), 251; https://doi.org/10.3390/toxins9080251 - 18 Aug 2017
Cited by 105 | Viewed by 9860
Abstract
Mycotoxins are fungal secondary metabolites with bioaccumulation levels leading to their carry-over into animal fluids, organs, and tissues. As a consequence, mycotoxin determination in biological samples from humans and animals has been reported worldwide. Since most mycotoxins show toxic effects at low concentrations [...] Read more.
Mycotoxins are fungal secondary metabolites with bioaccumulation levels leading to their carry-over into animal fluids, organs, and tissues. As a consequence, mycotoxin determination in biological samples from humans and animals has been reported worldwide. Since most mycotoxins show toxic effects at low concentrations and considering the extremely low levels present in biological samples, the application of reliable detection methods is required. This review summarizes the information regarding the studies involving mycotoxin determination in biological samples over the last 10 years. Relevant data on extraction methodology, detection techniques, sample size, limits of detection, and quantitation are presented herein. Briefly, liquid-liquid extraction followed by LC-MS/MS determination was the most common technique. The most analyzed mycotoxin was ochratoxin A, followed by zearalenone and deoxynivalenol—including their metabolites, enniatins, fumonisins, aflatoxins, T-2 and HT-2 toxins. Moreover, the studies were classified by their purpose, mainly focused on the development of analytical methodologies, mycotoxin biomonitoring, and exposure assessment. The study of tissue distribution, bioaccumulation, carry-over, persistence and transference of mycotoxins, as well as, toxicokinetics and ADME (absorption, distribution, metabolism and excretion) were other proposed goals for biological sample analysis. Finally, an overview of risk assessment was discussed. Full article
(This article belongs to the Collection Leading Opinions (Closed))
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Article
The Preparation and Identification of a Monoclonal Antibody against Domoic Acid and Establishment of Detection by Indirect Competitive ELISA
by Abdullah F. U. H. Saeed, Sumei Ling, Jun Yuan and Shihua Wang
Toxins 2017, 9(8), 250; https://doi.org/10.3390/toxins9080250 - 17 Aug 2017
Cited by 16 | Viewed by 6744
Abstract
Domoic acid (DA) is a potent toxin, marine biotoxin, and primarily produced by Pseudo-nitzschia. The DA hapten was coupled with bovine serum albumin (BSA), and ovalbumin (OVA) as carrier proteins. DA-BSA conjugate was used as immunogen and DA-OVA as coating antigen. Cell [...] Read more.
Domoic acid (DA) is a potent toxin, marine biotoxin, and primarily produced by Pseudo-nitzschia. The DA hapten was coupled with bovine serum albumin (BSA), and ovalbumin (OVA) as carrier proteins. DA-BSA conjugate was used as immunogen and DA-OVA as coating antigen. Cell fusion between spleen cells and sp2/0 myeloma cells developed 1C3 hybridoma clone producing 1C3 monoclonal antibody (mAb). Hybridoma was injected into the mice to produce ascites, and further purified by caprylic acid/ammonium sulfate method. The mAb was of IgG3 subclass, and was specific to DA with high affinity (2.5 × 108 L/mol). Moreover, western blot exhibited significant specificity to the DA antigens. Indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) showed DA working range of 0.006–0.2 ng/mL. The IC50 was 0.03 ng/mL with low limit of detection (LOD) of 0.006 ng/mL. Average DA recovery from spiked shellfish extract was 100.56% ± 2.8% with the coefficient variation of 0.01–0.1%. Hence, mAb producing 1C3 hybridoma was successfully developed and could be used to detect DA in contaminated samples. Full article
(This article belongs to the Section Marine and Freshwater Toxins)
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Article
Chemical Identity of Interaction of Protein with Reactive Metabolite of Diosbulbin B In Vitro and In Vivo
by Kai Wang, Dongju Lin, Xiucai Guo, Wenlin Huang, Jiang Zheng and Ying Peng
Toxins 2017, 9(8), 249; https://doi.org/10.3390/toxins9080249 - 14 Aug 2017
Cited by 26 | Viewed by 5375
Abstract
Diosbulbin B (DIOB), a hepatotoxic furan-containing compound, is a primary ingredient in Dioscorea bulbifera L., a common herbal medicine. Metabolic activation is required for DIOB-induced liver injury. Protein covalent binding of an electrophilic reactive intermediate of DIOB is considered to be one of [...] Read more.
Diosbulbin B (DIOB), a hepatotoxic furan-containing compound, is a primary ingredient in Dioscorea bulbifera L., a common herbal medicine. Metabolic activation is required for DIOB-induced liver injury. Protein covalent binding of an electrophilic reactive intermediate of DIOB is considered to be one of the key mechanisms of cytotoxicity. A bromine-based analytical technique was developed to characterize the chemical identity of interaction of protein with reactive intermediate of DIOB. Cysteine (Cys) and lysine (Lys) residues were found to react with the reactive intermediate to form three types of protein modification, including Cys adduction, Schiff’s base, and Cys/Lys crosslink. The crosslink showed time- and dose-dependence in animals given DIOB. Ketoconazole pretreatment decreased the formation of the crosslink derived from DIOB, whereas pretreatment with dexamethasone or buthionine sulfoximine increased such protein modification. These data revealed that the levels of hepatic protein adductions were proportional to the severity of hepatotoxicity of DIOB. Full article
(This article belongs to the Section Plant Toxins)
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Article
Lengths of the C-Terminus and Interconnecting Loops Impact Stability of Spider-Derived Gating Modifier Toxins
by Akello J. Agwa, Yen-Hua Huang, David J. Craik, Sónia T. Henriques and Christina I. Schroeder
Toxins 2017, 9(8), 248; https://doi.org/10.3390/toxins9080248 - 12 Aug 2017
Cited by 22 | Viewed by 5365
Abstract
Spider gating modifier toxins (GMTs) are potent modulators of voltage-gated ion channels and have thus attracted attention as drug leads for several pathophysiological conditions. GMTs contain three disulfide bonds organized in an inhibitory cystine knot, which putatively confers them with high stability; however, [...] Read more.
Spider gating modifier toxins (GMTs) are potent modulators of voltage-gated ion channels and have thus attracted attention as drug leads for several pathophysiological conditions. GMTs contain three disulfide bonds organized in an inhibitory cystine knot, which putatively confers them with high stability; however, thus far, there has not been a focused study to establish the stability of GMTs in physiological conditions. We examined the resistance of five GMTs including GpTx-1, HnTx-IV, HwTx-IV, PaurTx-3 and SgTx-1, to pH, thermal and proteolytic degradation. The peptides were stable under physiological conditions, except SgTx-1, which was susceptible to proteolysis, probably due to a longer C-terminus compared to the other peptides. In non-physiological conditions, the five peptides withstood chaotropic degradation, and all but SgTx-1 remained intact after prolonged exposure to high temperature; however, the peptides were degraded in strongly alkaline solutions. GpTx-1 and PaurTx-3 were more resistant to basic hydrolysis than HnTx-IV, HwTx-IV and SgTx-1, probably because a shorter interconnecting loop 3 on GpTx-1 and PaurTx-3 may stabilize interactions between the C-terminus and the hydrophobic patch. Here, we establish that most GMTs are exceptionally stable, and propose that, in the design of GMT-based therapeutics, stability can be enhanced by optimizing the C-terminus in terms of length, and increased interactions with the hydrophobic patch. Full article
(This article belongs to the Special Issue Toxins in Drug Discovery and Pharmacology)
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Review
Cellular Entry of Clostridium perfringens Iota-Toxin and Clostridium botulinum C2 Toxin
by Masaya Takehara, Teruhisa Takagishi, Soshi Seike, Masataka Oda, Yoshihiko Sakaguchi, Junzo Hisatsune, Sadayuki Ochi, Keiko Kobayashi and Masahiro Nagahama
Toxins 2017, 9(8), 247; https://doi.org/10.3390/toxins9080247 - 11 Aug 2017
Cited by 24 | Viewed by 7725
Abstract
Clostridium perfringens iota-toxin and Clostridium botulinum C2 toxin are composed of two non-linked proteins, one being the enzymatic component and the other being the binding/translocation component. These latter components recognize specific receptors and oligomerize in plasma membrane lipid-rafts, mediating the uptake of the [...] Read more.
Clostridium perfringens iota-toxin and Clostridium botulinum C2 toxin are composed of two non-linked proteins, one being the enzymatic component and the other being the binding/translocation component. These latter components recognize specific receptors and oligomerize in plasma membrane lipid-rafts, mediating the uptake of the enzymatic component into the cytosol. Enzymatic components induce actin cytoskeleton disorganization through the ADP-ribosylation of actin and are responsible for cell rounding and death. This review focuses upon the recent advances in cellular internalization of clostridial binary toxins. Full article
(This article belongs to the Special Issue Cellular Entry of Binary and Pore-Forming Bacterial Toxins)
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Article
Fusarium Mycotoxins in Swiss Wheat: A Survey of Growers’ Samples between 2007 and 2014 Shows Strong Year and Minor Geographic Effects
by Susanne Vogelgsang, Tomke Musa, Irene Bänziger, Andreas Kägi, Thomas D. Bucheli, Felix E. Wettstein, Matias Pasquali and Hans-Rudolf Forrer
Toxins 2017, 9(8), 246; https://doi.org/10.3390/toxins9080246 - 9 Aug 2017
Cited by 43 | Viewed by 6590 | Correction
Abstract
To assess the occurrence of Fusarium toxins in wheat in Switzerland, an eight-year survey was conducted by analysing a total of 686 harvest samples from growers using LC-MS/MS. Between 2007 and 2010, 527 samples were obtained from 17 cantons. Between 2011 and 2014, [...] Read more.
To assess the occurrence of Fusarium toxins in wheat in Switzerland, an eight-year survey was conducted by analysing a total of 686 harvest samples from growers using LC-MS/MS. Between 2007 and 2010, 527 samples were obtained from 17 cantons. Between 2011 and 2014, 159 samples were collected from the canton Berne. The most frequent toxins detected were deoxynivalenol (DON), zearalenone (ZEA) and nivalenol (NIV). The overall mean DON content in all samples was 607 µg/kg, and 11% exceeded the European limit for unprocessed cereals for foodstuffs (1250 µg/kg). For ZEA (mean 39 µg/kg), 7% exceeded the respective limit (100 µg/kg), and the mean content of NIV (no limit established) was 15 µg/kg. Between the years, the ratio of mycotoxin-contaminated samples ranged between 52% and 98% for DON, 9% and 43% for ZEA and 0% and 49% for NIV. The yearly mean contents varied substantially between 68 and 1310 µg/kg for DON, 5 and 56 µg/kg for ZEA and 6 and 29 µg/kg for NIV. The geographic origin showed a significant effect on DON and ZEA contamination, but was inconsistent between the years. This study has shown that the majority of Swiss-produced wheat is, in terms of Fusarium toxins, fit for human consumption and feed purposes. Nevertheless, depending on the year, high toxin contents can be expected, an issue that growers, cereal collection centres and the food industry have to deal with to ensure food and feed safety. Full article
(This article belongs to the Collection Understanding Mycotoxin Occurrence in Food and Feed Chains)
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Article
Spider Neurotoxins, Short Linear Cationic Peptides and Venom Protein Classification Improved by an Automated Competition between Exhaustive Profile HMM Classifiers
by Dominique Koua and Lucia Kuhn-Nentwig
Toxins 2017, 9(8), 245; https://doi.org/10.3390/toxins9080245 - 8 Aug 2017
Cited by 8 | Viewed by 5272
Abstract
Spider venoms are rich cocktails of bioactive peptides, proteins, and enzymes that are being intensively investigated over the years. In order to provide a better comprehension of that richness, we propose a three-level family classification system for spider venom components. This classification is [...] Read more.
Spider venoms are rich cocktails of bioactive peptides, proteins, and enzymes that are being intensively investigated over the years. In order to provide a better comprehension of that richness, we propose a three-level family classification system for spider venom components. This classification is supported by an exhaustive set of 219 new profile hidden Markov models (HMMs) able to attribute a given peptide to its precise peptide type, family, and group. The proposed classification has the advantages of being totally independent from variable spider taxonomic names and can easily evolve. In addition to the new classifiers, we introduce and demonstrate the efficiency of hmmcompete, a new standalone tool that monitors HMM-based family classification and, after post-processing the result, reports the best classifier when multiple models produce significant scores towards given peptide queries. The combined used of hmmcompete and the new spider venom component-specific classifiers demonstrated 96% sensitivity to properly classify all known spider toxins from the UniProtKB database. These tools are timely regarding the important classification needs caused by the increasing number of peptides and proteins generated by transcriptomic projects. Full article
(This article belongs to the Special Issue Animal Venoms and Pain)
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Article
Enzymatic and Pro-Inflammatory Activities of Bothrops lanceolatus Venom: Relevance for Envenomation
by Marie Delafontaine, Isadora Maria Villas-Boas, Laurence Mathieu, Patrice Josset, Joël Blomet and Denise V. Tambourgi
Toxins 2017, 9(8), 244; https://doi.org/10.3390/toxins9080244 - 7 Aug 2017
Cited by 27 | Viewed by 5590
Abstract
Bothrops lanceolatus, commonly named ‘Fer-de-Lance’, is an endemic snake of the French Caribbean Island of Martinique. Envenomations by B. lanceolatus present clinical aspects characterized by systemic thrombotic syndrome and important local inflammation, involving edema and pain but limited hemorrhage. To investigate mechanisms [...] Read more.
Bothrops lanceolatus, commonly named ‘Fer-de-Lance’, is an endemic snake of the French Caribbean Island of Martinique. Envenomations by B. lanceolatus present clinical aspects characterized by systemic thrombotic syndrome and important local inflammation, involving edema and pain but limited hemorrhage. To investigate mechanisms of venom-induced inflammation, B. lanceolatus venom was characterized, its cross-reactivity with bothropic antivenom explored, its cytotoxicity on human keratinocytes and vascular cells, and the production of cytokines and chemokines were analyzed. We used electrophoretic separation, zymography, colorimetric or fluorimetric enzymatic assays, and immunochemical assays. Therapeutic South American bothropic antivenom cross-reacted with B. lanceolatus venom and completely or partially abolished its PLA2, hyaluronidase, and proteolytic activities, as well as its cytotoxicity for keratinocytes. The substrate specificity of B. lanceolatus venom proteases was emphasized. B. lanceolatus venom cytotoxicity was compared to the B. jararaca venom. Both venoms were highly cytotoxic for keratinocytes (HaCaT), whereas B. lanceolatus venom showed particularly low toxicity for endothelial cells (EAhy926). Patterns of cytokine and chemokine production by cells exposed to the venoms were highly pro-inflammatory. Thus, the results presented here show that B. lanceolatus venom toxins share important antigenic similarities with South American Bothrops species toxins, although their proteases have acquired particular substrate specificity. Moreover, the venom displays important cytotoxic and pro-inflammatory action on human cell types such as keratinocytes and endothelial cells, which are important players in the local and systemic compartments affected by the envenomation. Full article
(This article belongs to the Section Animal Venoms)
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Article
Interaction between Various Apple Procyanidin and Staphylococcal Enterotoxin A and Their Inhibitory Effects on Toxin Activity
by Yuko Shimamura, Chikako Hirai, Yuka Sugiyama, Mio Utsumi, Akio Yanagida, Masatsune Murata, Norio Ohashi and Shuichi Masuda
Toxins 2017, 9(8), 243; https://doi.org/10.3390/toxins9080243 - 7 Aug 2017
Cited by 16 | Viewed by 5570
Abstract
In this study, we investigated the interaction between apple polyphenols (AP; mainly consisting of procyanidin (PC) from an apple) and staphylococcal enterotoxin A (SEA), and the inhibitory effects of AP on SEA activity. According to the degree of polymerization, in particularly highly polymerized [...] Read more.
In this study, we investigated the interaction between apple polyphenols (AP; mainly consisting of procyanidin (PC) from an apple) and staphylococcal enterotoxin A (SEA), and the inhibitory effects of AP on SEA activity. According to the degree of polymerization, in particularly highly polymerized PC (more than pentamer) strongly interacted with SEA. The binding affinity of AP with SEA molecules was determined using Biacore analysis. AP reacted with SEA immobilized on a Biacore sensor chip. After treatment with pepsin and pancreatin, to examine the changes of binding affinity of AP in intragastric conditions, AP maintained interaction with SEA. We examined whether AP inhibits the proliferation and interferon-γ (IFN-γ) production induced by SEA in mouse spleen cells. AP strongly inactivated the proliferation and IFN-γ production induced by SEA. These results suggest that AP, which has a higher degree of polymerization, inactivates stronger biological activity of SEA through interaction with SEA. Our studies are the first to demonstrate the relationship between the degree of polymerization of AP and the inhibitory effects on SEA activities. Full article
(This article belongs to the Special Issue Heat-Stable Enterotoxins)
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Article
Enter the Dragon: The Dynamic and Multifunctional Evolution of Anguimorpha Lizard Venoms
by Ivan Koludarov, Timothy NW Jackson, Bianca op den Brouw, James Dobson, Daniel Dashevsky, Kevin Arbuckle, Christofer J. Clemente, Edward J. Stockdale, Chip Cochran, Jordan Debono, Carson Stephens, Nadya Panagides, Bin Li, Mary-Louise Roy Manchadi, Aude Violette, Rudy Fourmy, Iwan Hendrikx, Amanda Nouwens, Judith Clements, Paolo Martelli, Hang Fai Kwok and Bryan G. Fryadd Show full author list remove Hide full author list
Toxins 2017, 9(8), 242; https://doi.org/10.3390/toxins9080242 - 6 Aug 2017
Cited by 38 | Viewed by 31627
Abstract
While snake venoms have been the subject of intense study, comparatively little work has been done on lizard venoms. In this study, we have examined the structural and functional diversification of anguimorph lizard venoms and associated toxins, and related these results to dentition [...] Read more.
While snake venoms have been the subject of intense study, comparatively little work has been done on lizard venoms. In this study, we have examined the structural and functional diversification of anguimorph lizard venoms and associated toxins, and related these results to dentition and predatory ecology. Venom composition was shown to be highly variable across the 20 species of Heloderma, Lanthanotus, and Varanus included in our study. While kallikrein enzymes were ubiquitous, they were also a particularly multifunctional toxin type, with differential activities on enzyme substrates and also ability to degrade alpha or beta chains of fibrinogen that reflects structural variability. Examination of other toxin types also revealed similar variability in their presence and activity levels. The high level of venom chemistry variation in varanid lizards compared to that of helodermatid lizards suggests that venom may be subject to different selection pressures in these two families. These results not only contribute to our understanding of venom evolution but also reveal anguimorph lizard venoms to be rich sources of novel bioactive molecules with potential as drug design and development lead compounds. Full article
(This article belongs to the Collection Evolution of Venom Systems)
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Article
Prevalence and Genetic Characteristics of Staphylococcus aureus and Staphylococcus argenteus Isolates Harboring Panton-Valentine Leukocidin, Enterotoxins, and TSST-1 Genes from Food Handlers in Myanmar
by Meiji Soe Aung, Thida San, Mya Mya Aye, San Mya, Win Win Maw, Khin Nyein Zan, Wut Hmone Win Htut, Mitsuyo Kawaguchiya, Noriko Urushibara and Nobumichi Kobayashi
Toxins 2017, 9(8), 241; https://doi.org/10.3390/toxins9080241 - 4 Aug 2017
Cited by 59 | Viewed by 8426
Abstract
Asymptomatic carriers of toxigenic Staphylococcus aureus are potential source of diseases, including food poisoning. Toxigenic potential and genetic traits of colonizing S. aureus were investigated for 563 healthy food handlers in Myanmar. Carriage of S. aureus was found in 110 individuals (19.5%), and [...] Read more.
Asymptomatic carriers of toxigenic Staphylococcus aureus are potential source of diseases, including food poisoning. Toxigenic potential and genetic traits of colonizing S. aureus were investigated for 563 healthy food handlers in Myanmar. Carriage of S. aureus was found in 110 individuals (19.5%), and a total of 144 S. aureus isolates were recovered from nasal cavities (110 isolates) and hands (34 isolates). Panton-Valentine leucocidin genes (pvl) were detected in 18 isolates (12.5%), among which 11 isolates were classified into coa-VIa, agr type III, and ST1930 (CC96) that had been also detected in pvl-positive clinical isolates in Myanmar. A pvl-positive, ST2250 nasal isolate was identified as S. argenteus, a novel coagulase-positive staphylococcus species. Toxic shock syndrome toxin-1 (TSST-1) gene was detected in five pvl-negative isolates. All of the 144 isolates harbored at least one of the 21 enterotoxin(-like) gene(s). The most prevalent enterotoxin(-like) gene was selw (98%), followed by selx (97%), sei (28%), sely (28%), sem (26%), sel (24%), and sea and sec (22% each). Considerable genetic diversity with five groups was detected for selw. The present study revealed the relatively high rate of pvl, as well as the wide distribution of enterotoxin(-like) genes among colonizing S. aureus in Myanmar. Full article
(This article belongs to the Collection Staphylococcus aureus Toxins)
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Article
Sex Is a Determinant for Deoxynivalenol Metabolism and Elimination in the Mouse
by James J. Pestka, Erica S. Clark, Heidi E. Schwartz-Zimmermann and Franz Berthiller
Toxins 2017, 9(8), 240; https://doi.org/10.3390/toxins9080240 - 4 Aug 2017
Cited by 23 | Viewed by 6617 | Correction
Abstract
Based on prior observations that deoxynivalenol (DON) toxicity is sex-dependent, we compared metabolism and clearance of this toxin in male and female mice. Following intraperitoneal challenge with 1 mg/kg bw DON, the dose used in the aforementioned toxicity study, ELISA and LC–MS/MS analyses [...] Read more.
Based on prior observations that deoxynivalenol (DON) toxicity is sex-dependent, we compared metabolism and clearance of this toxin in male and female mice. Following intraperitoneal challenge with 1 mg/kg bw DON, the dose used in the aforementioned toxicity study, ELISA and LC–MS/MS analyses revealed that by 24 h, most DON and DON metabolites were excreted via urine (49–86%) as compared to feces (1.2–8.3%). Females excreted DON and its principal metabolites (DON-3-, DON-8,15 hemiketal-8-, and iso-DON-8-glucuronides) in urine more rapidly than males. Metabolite concentrations were typically 2 to 4 times higher in the livers and kidneys of males than females from 1 to 4 h after dosing. Trace levels of DON-3-sulfate and DON-15-sulfate were found in urine, liver and kidneys from females but not males. Fecal excretion of DON and DON sulfonates was approximately 2-fold greater in males than females. Finally, decreased DON clearance rates in males could not be explained by glucuronidation activities in liver and kidney microsomes. To summarize, increased sensitivity of male mice to DON’s toxic effects as compared to females corresponds to decreased ability to clear the toxin via urine but did not appear to result from differences in toxin metabolism. Full article
(This article belongs to the Collection Fusarium Toxins – Relevance for Human and Animal Health)
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Article
Insights into the Mechanisms Involved in Strong Hemorrhage and Dermonecrosis Induced by Atroxlysin-Ia, a PI-Class Snake Venom Metalloproteinase
by Luciana Aparecida Freitas-de-Sousa, Mônica Colombini, Mônica Lopes-Ferreira, Solange M. T. Serrano and Ana Maria Moura-da-Silva
Toxins 2017, 9(8), 239; https://doi.org/10.3390/toxins9080239 - 2 Aug 2017
Cited by 42 | Viewed by 6356
Abstract
Hemorrhage is the most prominent effect of snake venom metalloproteinases (SVMPs) in human envenomation. The capillary injury is a multifactorial effect caused by hydrolysis of the components of the basement membrane (BM). The PI and PIII classes of SVMPs are abundant in viperid [...] Read more.
Hemorrhage is the most prominent effect of snake venom metalloproteinases (SVMPs) in human envenomation. The capillary injury is a multifactorial effect caused by hydrolysis of the components of the basement membrane (BM). The PI and PIII classes of SVMPs are abundant in viperid venoms and hydrolyze BM components. However, hemorrhage is associated mostly with PIII-class SVMPs that contain non-catalytic domains responsible for the binding of SVMPs to BM proteins, facilitating enzyme accumulation in the tissue and enhancing its catalytic efficiency. Here we report on Atroxlysin-Ia, a PI-class SVMP that induces hemorrhagic lesions in levels comparable to those induced by Batroxrhagin (PIII-class), and a unique SVMP effect characterized by the rapid onset of dermonecrotic lesions. Atroxlysin-Ia was purified from B. atrox venom, and sequence analyses indicated that it is devoid of non-catalytic domains and unable to bind to BM proteins as collagen IV and laminin in vitro or in vivo. The presence of Atroxlysin-Ia was diffuse in mice skin, and localized mainly in the epidermis with no co-localization with BM components. Nevertheless, the skin lesions induced by Atroxlysin-Ia were comparable to those induced by Batroxrhagin, with induction of leukocyte infiltrates and hemorrhagic areas soon after toxin injection. Detachment of the epidermis was more intense in skin injected with Atroxlysin-Ia. Comparing the catalytic activity of both toxins, Batroxrhagin was more active in the hydrolysis of a peptide substrate while Atroxlysin-Ia hydrolyzed more efficiently fibrin, laminin, collagen IV and nidogen. Thus, the results suggest that Atroxlysin-Ia bypasses the binding step to BM proteins, essential for hemorrhagic lesions induced by PII- and P-III class SVMPs, causing a significantly fast onset of hemorrhage and dermonecrosis, due to its higher proteolytic capacity on BM components. Full article
(This article belongs to the Section Animal Venoms)
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1872 KiB  
Article
Analysis of the Masked Metabolite of Deoxynivalenol and Fusarium Resistance in CIMMYT Wheat Germplasm
by Hiroyuki Nakagawa, Xinyao He, Yosuke Matsuo, Pawan K. Singh and Masayo Kushiro
Toxins 2017, 9(8), 238; https://doi.org/10.3390/toxins9080238 - 29 Jul 2017
Cited by 18 | Viewed by 6748
Abstract
Fusarium head blight (FHB) causes significant grain loss and contamination of grains with harmful mycotoxins, especially deoxynivalenol (DON). Fusarium resistance and DON accumulation have been extensively investigated in various cultivars; however, the level of DON-3-O-glucoside (D3G) has not been as carefully [...] Read more.
Fusarium head blight (FHB) causes significant grain loss and contamination of grains with harmful mycotoxins, especially deoxynivalenol (DON). Fusarium resistance and DON accumulation have been extensively investigated in various cultivars; however, the level of DON-3-O-glucoside (D3G) has not been as carefully studied. In this study, we measured accumulated DON and D3G levels in CIMMYT wheat elite germplasm using an analytical method validated in-house. Co-occurring nivalenol (NIV) and ergostrerol (ERG) were also analyzed. LC-MS/MS and LC-UV analyses were applied to the 50 CIMMYT elite wheat lines. D3G showed rather high correlation with DON (r = 0.82), while FHB symptoms showed slight correlation with DON and D3G (r = 0.36 and 0.32, respectively). D3G/DON ratio varied widely from 8.1 to 37.7%, and the ratio was not related with FHB resistance in this dataset. Full article
(This article belongs to the Collection Understanding Mycotoxin Occurrence in Food and Feed Chains)
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3072 KiB  
Article
The Middle Fragment of Helicobacter pylori CagA Induces Actin Rearrangement and Triggers Its Own Uptake into Gastric Epithelial Cells
by Abolghasem Tohidpour, Rebecca J. Gorrell, Anna Roujeinikova and Terry Kwok
Toxins 2017, 9(8), 237; https://doi.org/10.3390/toxins9080237 - 28 Jul 2017
Cited by 13 | Viewed by 6805
Abstract
Cytotoxin-associated gene product A (CagA) is a major virulence factor secreted by Helicobacter pylori. CagA activity in the gastric epithelium is associated with higher risk of gastric cancer development. Bacterial type IV secretion system (T4SS)-mediated translocation of CagA into the cytosol of [...] Read more.
Cytotoxin-associated gene product A (CagA) is a major virulence factor secreted by Helicobacter pylori. CagA activity in the gastric epithelium is associated with higher risk of gastric cancer development. Bacterial type IV secretion system (T4SS)-mediated translocation of CagA into the cytosol of human epithelial cells occurs via a poorly understood mechanism that requires CagA interaction with the host membrane lipid phosphatidylserine (PS) and host cell receptor integrin α5β1. Here we have characterized the isolated recombinant middle fragment of CagA (CagA-M) that contains the positively-charged PS-binding region (aa 613–636) and a putative β1 integrin binding site, but lacks the EPIYA region, secretion signal peptide and the CagA multimerization motif. We show that CagA-M, when immobilized on latex beads, is capable of binding to, and triggering its own uptake into, gastric epithelial cells in the absence of infection with cagA-positive H. pylori. Using site-directed mutagenesis, fluorescent and electron microscopy, and highly-specific inhibitors, we demonstrate that the cell-binding and endocytosis-like internalization of CagA-M are dependent on (1) binding to PS; (2) β1 integrin activity; and (3) actin dynamics. Interaction of CagA-M with the host cells is accompanied by the development of long filopodia-like protrusions (macrospikes). This novel morphology is different from the hummingbird phenotype induced by the translocation of full-length CagA. The determinants within CagA-M and within the host that are important for endocytosis-like internalization into host cells are very similar to those observed for T4SS-mediated internalization of full-length CagA, suggesting that the latter may involve an endocytic pathway. Full article
(This article belongs to the Special Issue H. pylori Virulence Factors in the Induction of Gastric Cancer)
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1449 KiB  
Review
Bacterial Toxins for Cancer Therapy
by Nour-Imene Zahaf and Gudula Schmidt
Toxins 2017, 9(8), 236; https://doi.org/10.3390/toxins9080236 - 28 Jul 2017
Cited by 67 | Viewed by 12793
Abstract
Several pathogenic bacteria secrete toxins to inhibit the immune system of the infected organism. Frequently, they catalyze a covalent modification of specific proteins. Thereby, they block production and/or secretion of antibodies or cytokines. Moreover, they disable migration of macrophages and disturb the barrier [...] Read more.
Several pathogenic bacteria secrete toxins to inhibit the immune system of the infected organism. Frequently, they catalyze a covalent modification of specific proteins. Thereby, they block production and/or secretion of antibodies or cytokines. Moreover, they disable migration of macrophages and disturb the barrier function of epithelia. In most cases, these toxins are extremely effective enzymes with high specificity towards their cellular substrates, which are often central signaling molecules. Moreover, they encompass the capacity to enter mammalian cells and to modify their substrates in the cytosol. A few molecules, at least of some toxins, are sufficient to change the cellular morphology and function of a cell or even kill a cell. Since many of those toxins are well studied concerning molecular mechanisms, cellular receptors, uptake routes, and structures, they are now widely used to analyze or to influence specific signaling pathways of mammalian cells. Here, we review the development of immunotoxins and targeted toxins for the treatment of a disease that is still hard to treat: cancer. Full article
(This article belongs to the Collection Leading Opinions (Closed))
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1711 KiB  
Article
Sensitive Detection of α-Conotoxin GI in Human Plasma Using a Solid-Phase Extraction Column and LC-MS/MS
by Shuo Yu, Bo Yang, Liangping Yan and Qiuyun Dai
Toxins 2017, 9(8), 235; https://doi.org/10.3390/toxins9080235 - 28 Jul 2017
Cited by 3 | Viewed by 4505
Abstract
α-conotoxin GI, a short peptide toxin in the venom of Conus geographus, is composed of 13 amino acids and two disulfide bonds. It is the most toxic component of Conus geographus venom with estimated lethal doses of 0.029–0.038 mg/kg for humans. There [...] Read more.
α-conotoxin GI, a short peptide toxin in the venom of Conus geographus, is composed of 13 amino acids and two disulfide bonds. It is the most toxic component of Conus geographus venom with estimated lethal doses of 0.029–0.038 mg/kg for humans. There is currently no reported analytical method for this toxin. In the present study, a sensitive detection method was developed to quantify GI in human plasma using a solid-phase extraction (SPE) column (polystyrene–divinyl benzene copolymer) combined with liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) in the multiple reaction monitoring (MRM) mode. The plasma samples were treated with a protein precipitating solvent (methanol: acetonitrile = 50:50, v/v). GI in the solvent was efficiently extracted with an SPE column and was further separated by a Grace Alltima HP C18 (50 × 2.1 mm, 5 μm) column at a flow rate of 0.4 mL/min. Water (with 2% methanol) acetonitrile (with 0.1% acetic acid) was selected as the mobile phase combination used in a linear gradient system. α-Conotoxin GI was analyzed by an API 4000 triple quadrupole mass spectrometer. In the method validation, the linear calibration curve in the range of 2.0 to 300.0 ng/mL had correlation coefficients (r) above 0.996. The recovery was 57.6–66.8% for GI and the internal standard. The lower limit of quantification (LLOQ) was 2 ng/mL. The intra- and inter-batch precisions were below 6.31% and 8.61%, respectively, and the accuracies were all within acceptance. GI was stable in a bench-top autosampler through long-term storage and freeze/thaw cycles. Therefore, this method is specific, sensitive and reliable for quantitative analysis of α-conotoxin GI in human plasma. Full article
(This article belongs to the Section Animal Venoms)
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7945 KiB  
Article
Venomics of Remipede Crustaceans Reveals Novel Peptide Diversity and Illuminates the Venom’s Biological Role
by Björn M. Von Reumont, Eivind A. B. Undheim, Robin-Tobias Jauss and Ronald A. Jenner
Toxins 2017, 9(8), 234; https://doi.org/10.3390/toxins9080234 - 26 Jul 2017
Cited by 29 | Viewed by 11890
Abstract
We report the first integrated proteomic and transcriptomic investigation of a crustacean venom. Remipede crustaceans are the venomous sister group of hexapods, and the venom glands of the remipede Xibalbanus tulumensis express a considerably more complex cocktail of proteins and peptides than previously [...] Read more.
We report the first integrated proteomic and transcriptomic investigation of a crustacean venom. Remipede crustaceans are the venomous sister group of hexapods, and the venom glands of the remipede Xibalbanus tulumensis express a considerably more complex cocktail of proteins and peptides than previously thought. We identified 32 venom protein families, including 13 novel peptide families that we name xibalbins, four of which lack similarities to any known structural class. Our proteomic data confirm the presence in the venom of 19 of the 32 families. The most highly expressed venom components are serine peptidases, chitinase and six of the xibalbins. The xibalbins represent Inhibitory Cystine Knot peptides (ICK), a double ICK peptide, peptides with a putative Cystine-stabilized α-helix/β-sheet motif, a peptide similar to hairpin-like β-sheet forming antimicrobial peptides, two peptides related to different hormone families, and four peptides with unique structural motifs. Remipede venom components represent the full range of evolutionary recruitment frequencies, from families that have been recruited into many animal venoms (serine peptidases, ICKs), to those having a very narrow taxonomic range (double ICKs), to those unique for remipedes. We discuss the most highly expressed venom components to shed light on their possible functional significance in the predatory and defensive use of remipede venom, and to provide testable ideas for any future bioactivity studies. Full article
(This article belongs to the Section Animal Venoms)
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5361 KiB  
Article
Different Metabolic Pathways Are Involved in Response of Saccharomyces cerevisiae to L-A and M Viruses
by Juliana Lukša, Bazilė Ravoitytė, Aleksandras Konovalovas, Lina Aitmanaitė, Anzhelika Butenko, Vyacheslav Yurchenko, Saulius Serva and Elena Servienė
Toxins 2017, 9(8), 233; https://doi.org/10.3390/toxins9080233 - 25 Jul 2017
Cited by 19 | Viewed by 5726
Abstract
Competitive and naturally occurring yeast killer phenotype is governed by coinfection with dsRNA viruses. Long-term relationship between the host cell and viruses appear to be beneficial and co-adaptive; however, the impact of viral dsRNA on the host gene expression has barely been investigated. [...] Read more.
Competitive and naturally occurring yeast killer phenotype is governed by coinfection with dsRNA viruses. Long-term relationship between the host cell and viruses appear to be beneficial and co-adaptive; however, the impact of viral dsRNA on the host gene expression has barely been investigated. Here, we determined the transcriptomic profiles of the host Saccharomyces cerevisiae upon the loss of the M-2 dsRNA alone and the M-2 along with the L-A-lus dsRNAs. We provide a comprehensive study based on the high-throughput RNA-Seq data, Gene Ontology and the analysis of the interaction networks. We identified 486 genes differentially expressed after curing yeast cells of the M-2 dsRNA and 715 genes affected by the elimination of both M-2 and L-A-lus dsRNAs. We report that most of the transcriptional responses induced by viral dsRNAs are moderate. Differently expressed genes are related to ribosome biogenesis, mitochondrial functions, stress response, biosynthesis of lipids and amino acids. Our study also provided insight into the virus–host and virus–virus interplays. Full article
(This article belongs to the Special Issue Yeast Killer Toxins)
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