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Toxins, Volume 2, Issue 1 (January 2010) – 12 articles , Pages 1-204

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325 KiB  
Article
PP2A Inhibition Assay Using Recombinant Enzyme for Rapid Detection of Okadaic Acid and Its Analogs in Shellfish
by Tsuyoshi Ikehara, Shihoko Imamura, Atsushi Yoshino and Takeshi Yasumoto
Toxins 2010, 2(1), 195-204; https://doi.org/10.3390/toxins2010195 - 25 Jan 2010
Cited by 27 | Viewed by 10346
Abstract
Okadaic acid and its analogs (OAs) responsible for diarrhetic shellfish poisoning (DSP) strongly inhibit protein phosphatase 2A (PP2A) and thus are quantifiable by measuring the extent of the enzyme inhibition. In this study, we evaluated the suitability of the catalytic subunit of recombinant [...] Read more.
Okadaic acid and its analogs (OAs) responsible for diarrhetic shellfish poisoning (DSP) strongly inhibit protein phosphatase 2A (PP2A) and thus are quantifiable by measuring the extent of the enzyme inhibition. In this study, we evaluated the suitability of the catalytic subunit of recombinant human PP2A (rhPP2Ac) for use in a microplate OA assay. OA, dinophysistoxin-1(DTX1), and hydrolyzate of 7-O-palmitoyl-OA strongly inhibited rhPP2Ac activity with IC50 values of 0.095, 0.104, and 0.135 nM, respectively. The limits of detection and quantitation for OA in the digestive gland of scallops and mussels were 0.0348 μg/g and 0.0611 μg/g respectively, and, when converted to the whole meat basis, are well below the regulation level proposed by EU (0.16 μg/g whole meat). A good correlation with LC-MS data was demonstrated, the correlation coefficient being 0.996 with the regression slope of 1.097. Full article
(This article belongs to the Special Issue Marine Biotoxins: Novel Issues about Old Compounds)
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457 KiB  
Review
The Protein Kinase C Agonist PEP005 (Ingenol 3-Angelate) in the Treatment of Human Cancer: A Balance between Efficacy and Toxicity
by Elisabeth Ersvaer, Astrid Olsnes Kittang, Peter Hampson, Kristoffer Sand, Bjørn Tore Gjertsen, Janet M. Lord and Øystein Bruserud
Toxins 2010, 2(1), 174-194; https://doi.org/10.3390/toxins2010174 - 22 Jan 2010
Cited by 57 | Viewed by 14559
Abstract
The diterpene ester ingenol-3-angelate (referred to as PEP005) is derived from the plant Euphorbia peplus. Crude euphorbia extract causes local toxicity and transient inflammation when applied topically and has been used in the treatment of warts, skin keratoses and skin cancer. PEP005 [...] Read more.
The diterpene ester ingenol-3-angelate (referred to as PEP005) is derived from the plant Euphorbia peplus. Crude euphorbia extract causes local toxicity and transient inflammation when applied topically and has been used in the treatment of warts, skin keratoses and skin cancer. PEP005 is a broad range activator of the classical (α, β, γ) and novel (δ, ε, η, θ) protein kinase C isoenzymes. Direct pro-apoptotic effects of this drug have been demonstrated in several malignant cells, including melanoma cell lines and primary human acute myelogenous leukemia cells. At micromolar concentrations required to kill melanoma cells this agent causes PKC-independent secondary necrosis. In contrast, the killing of leukemic cells occurs in the nanomolar range, requires activation of protein kinase C δ (PKCδ) and is specifically associated with translocation of PKCδ from the cytoplasm to the nuclear membrane. However, in addition to this pro-apoptotic effect the agent seems to have immunostimulatory effects, including: (i) increased chemokine release by malignant cells; (ii) a general increase in proliferation and cytokine release by activated T cells, including T cells derived from patients with chemotherapy-induced lymphopenia; (iii) local infiltration of neutrophils after topical application with increased antibody-dependent cytotoxicity; and (iv) development of specific anti-cancer immune responses by CD8+ T cells in animal models. Published studies mainly describe effects from in vitro investigations or after topical application of the agent, and careful evaluation of the toxicity after systemic administration is required before the possible use of this agent in the treatment of malignancies other than skin cancers. Full article
(This article belongs to the Collection Toxicity and Therapeutic Interventions in the Immune System)
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Review
Bothrops lanceolatus Bites: Guidelines for Severity Assessment and Emergent Management
by Dabor Resiere, Bruno Mégarbane, Ruddy Valentino, Hossein Mehdaoui and Laurent Thomas
Toxins 2010, 2(1), 163-173; https://doi.org/10.3390/toxins2010163 - 22 Jan 2010
Cited by 39 | Viewed by 14668
Abstract
Approximately 20–30 declared snakebite cases occurin Martinique each year. Bothrops lanceolatus, a member of the Crotalidae family, is considered to be the only involved snake. B. lanceolatus, commonly named “Fer-de-Lance”, is endemic and only found on this Caribbean island. Envenomation local [...] Read more.
Approximately 20–30 declared snakebite cases occurin Martinique each year. Bothrops lanceolatus, a member of the Crotalidae family, is considered to be the only involved snake. B. lanceolatus, commonly named “Fer-de-Lance”, is endemic and only found on this Caribbean island. Envenomation local features include the presence of fang marks, swelling, pain, bleeding from punctures, and ecchymosis. Severe envenomation is associated with multiple systemic thromboses appearing within 48 h of the bite and resulting in cerebral, myocardial or pulmonary infarctions. Diagnosis requires first of all identification of the snake. Coagulation tests are helpful to identify thrombocytopenia or disseminated intravascular coagulation. A clinical score based on 4 grades is helpful to assess envonimation severity. A specific monovalent equine anti-venom (Bothrofav®, Sanofi-Pasteur, France) to neutralize B. lanceolatus venom is available. Its early administration within 6h from the biting in case of progressive local injures, general signs or coagulation disturbances is effective to prevent severe thrombosis and coagulopathy. Its tolerance is considered to be good. Despite an increasing incidence of bites, no deaths have been recently attributed to B. lanceolatus in Martinique, probably due to the currently recommended strategy of early antivenom administration when required. Full article
(This article belongs to the Special Issue Animal Venoms)
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631 KiB  
Review
Curcumin―The Paradigm of a Multi-Target Natural Compound with Applications in Cancer Prevention and Treatment
by Marie-Hélène Teiten, Serge Eifes, Mario Dicato and Marc Diederich
Toxins 2010, 2(1), 128-162; https://doi.org/10.3390/toxins2010128 - 21 Jan 2010
Cited by 175 | Viewed by 20457
Abstract
As cancer is a multifactor disease, it may require treatment with compounds able to target multiple intracellular components. We summarize here how curcumin is able to modulate many components of intracellular signaling pathways implicated in inflammation, cell proliferation and invasion and to induce [...] Read more.
As cancer is a multifactor disease, it may require treatment with compounds able to target multiple intracellular components. We summarize here how curcumin is able to modulate many components of intracellular signaling pathways implicated in inflammation, cell proliferation and invasion and to induce genetic modulations eventually leading to tumor cell death. Clinical applications of this natural compound were initially limited by its low solubility and bioavailability in both plasma and tissues but combination with adjuvant and delivery vehicles was reported to largely improve bio-availability of curcumin. Moreover, curcumin was reported to act in synergism with several natural compounds or synthetic agents commonly used in chemotherapy. Based on this, curcumin could thus be considered as a good candidate for cancer prevention and treatment when used alone or in combination with other conventional treatments. Full article
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394 KiB  
Review
Cytotoxic Necrotizing Factors (CNFs)−A Growing Toxin Family
by Zeynep Knust and Gudula Schmidt
Toxins 2010, 2(1), 116-127; https://doi.org/10.3390/toxins2010116 - 21 Jan 2010
Cited by 39 | Viewed by 11527
Abstract
The Escherichia coli Cytotoxic Necrotizing Factors, CNF1, CNF2, CNF3 and CNFY from Yersinia pseudotuberculosis belong to a family of deamidating toxins. CNFs deamidate glutamine 63/61 in the switch II region of Rho GTPases that is essential for GTP hydrolysing activity. Deamidation leads to [...] Read more.
The Escherichia coli Cytotoxic Necrotizing Factors, CNF1, CNF2, CNF3 and CNFY from Yersinia pseudotuberculosis belong to a family of deamidating toxins. CNFs deamidate glutamine 63/61 in the switch II region of Rho GTPases that is essential for GTP hydrolysing activity. Deamidation leads to constitutive activation of Rho GTPases. However, cellular mechanisms like proteasomal degradation of the activated Rho proteins restrict the action of the GTPases. This review describes the differences between the toxin family members concerning expression, cellular entry and substrate specificity. Full article
(This article belongs to the Special Issue Bacterial Protein Toxins)
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Article
Calprotectin (S100A8/S100A9) and Myeloperoxidase: Co-Regulators of Formation of Reactive Oxygen Species
by Arne Bøyum, Knut Kristian Skrede, Oddvar Myhre, Vivi-Ann Tennfjord, Christine Gran Neurauter, Helge Tolleshaug, Eirunn Knudsen, Per Kristian Opstad, Magnar Bjørås and Haakon B. Benestad
Toxins 2010, 2(1), 95-115; https://doi.org/10.3390/toxins2010095 - 20 Jan 2010
Cited by 13 | Viewed by 15724
Abstract
Inflammatory mediators trigger polymorphonuclear neutrophils (PMN) to produce reactive oxygen species (ROS: O2-, H2O2, ∙OH). Mediated by myeloperoxidase in PMN, HOCl is formed, detectable in a chemiluminescence (CL) assay. We have shown that the abundant cytosolic PMN [...] Read more.
Inflammatory mediators trigger polymorphonuclear neutrophils (PMN) to produce reactive oxygen species (ROS: O2-, H2O2, ∙OH). Mediated by myeloperoxidase in PMN, HOCl is formed, detectable in a chemiluminescence (CL) assay. We have shown that the abundant cytosolic PMN protein calprotectin (S100A8/A9) similarly elicits CL in response to H2O2 in a cell-free system. Myeloperoxidase and calprotectin worked synergistically. Calprotectin-induced CL increased, whereas myeloperoxidase-triggered CL decreased with pH > 7.5. Myeloperoxidase needed NaCl for CL, calprotectin did not. 4-hydroxybenzoic acid, binding ∙OH, almost abrogated calprotectin CL, but moderately increased myeloperoxidase activity. The combination of native calprotectin, or recombinant S100A8/A9 proteins, with NaOCl markedly enhanced CL. NaOCl may be the synergistic link between myeloperoxidase and calprotectin. Surprisingly- and unexplained- at higher concentration of S100A9 the stimulation vanished, suggesting a switch from pro-oxidant to anti-oxidant function. We propose that the ∙OH is predominant in ROS production by calprotectin, a function not described before. Full article
(This article belongs to the Collection Toxicity and Therapeutic Interventions in the Immune System)
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73 KiB  
Correction
Correction: Čapek, P., et al. Sensing the Deadliest Toxin: Technologies for Botulinum Neurotoxin Detection. Toxins 2010, 2, 24-53
by Petr Čapek and Tobin J. Dickerson
Toxins 2010, 2(1), 93-94; https://doi.org/10.3390/toxins2010093 - 19 Jan 2010
Cited by 36 | Viewed by 8050
Abstract
We realized that in our paper published recently in Toxins [1] limits of detection (LOD) of multiplexed fluorescent magnetic suspension assay [2] were incorrectly reported to be in the ng/mL range. [...] Full article
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Article
The Versatility of the Helicobacter pylori Vacuolating Cytotoxin VacA in Signal Transduction and Molecular Crosstalk
by Steffen Backert and Nicole Tegtmeyer
Toxins 2010, 2(1), 69-92; https://doi.org/10.3390/toxins2010069 - 15 Jan 2010
Cited by 31 | Viewed by 13156
Abstract
By modulating important properties of eukaryotic cells, many bacterial protein toxins highjack host signalling pathways to create a suitable niche for the pathogen to colonize and persist. Helicobacter pylori VacA is paradigm of pore-forming toxins which contributes to the pathogenesis of peptic ulceration. [...] Read more.
By modulating important properties of eukaryotic cells, many bacterial protein toxins highjack host signalling pathways to create a suitable niche for the pathogen to colonize and persist. Helicobacter pylori VacA is paradigm of pore-forming toxins which contributes to the pathogenesis of peptic ulceration. Several cellular receptors have been described for VacA, which exert different effects on epithelial and immune cells. The crystal structure of VacA p55 subunit might be important for elucidating details of receptor interaction and pore formation. Here we discuss the multiple signalling activities of this important toxin and the molecular crosstalk between VacA and other virulence factors. Full article
(This article belongs to the Special Issue Bacterial Protein Toxins)
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640 KiB  
Review
Reciprocal Interactions between Lactoferrin and Bacterial Endotoxins and Their Role in the Regulation of the Immune Response
by Daniela Latorre, Patrizia Puddu, Piera Valenti and Sandra Gessani
Toxins 2010, 2(1), 54-68; https://doi.org/10.3390/toxins2010054 - 08 Jan 2010
Cited by 51 | Viewed by 12724
Abstract
Lactoferrin (Lf), an iron-binding glycoprotein expressed in most biological fluids, represents a major component of the mammalian innate immune system. Lf’s multiple activities rely not only on its capacity to bind iron, but also to interact with molecular and cellular components of both [...] Read more.
Lactoferrin (Lf), an iron-binding glycoprotein expressed in most biological fluids, represents a major component of the mammalian innate immune system. Lf’s multiple activities rely not only on its capacity to bind iron, but also to interact with molecular and cellular components of both host and pathogens. Lf can bind and sequester lipopolysaccharide (LPS), thus preventing pro-inflammatory pathway activation, sepsis and tissue damage. However, Lf-bound LPS may retain the capacity to induce cell activation via Toll-like receptor 4-dependent and -independent mechanisms. This review discusses the complex interplay between Lf and LPS and its relevance in the regulation of the immune response. Full article
(This article belongs to the Collection Toxicity and Therapeutic Interventions in the Immune System)
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Review
Sensing the Deadliest Toxin: Technologies for Botulinum Neurotoxin Detection
by Petr Čapek and Tobin J. Dickerson
Toxins 2010, 2(1), 24-53; https://doi.org/10.3390/toxins2010024 - 07 Jan 2010
Cited by 62 | Viewed by 22209 | Correction
Abstract
Sensitive and rapid detection of botulinum neurotoxins (BoNTs), the most poisonous substances known to date, is essential for studies of medical applications of BoNTs and detection of poisoned food, as well as for response to potential bioterrorist threats. Currently, the most common method [...] Read more.
Sensitive and rapid detection of botulinum neurotoxins (BoNTs), the most poisonous substances known to date, is essential for studies of medical applications of BoNTs and detection of poisoned food, as well as for response to potential bioterrorist threats. Currently, the most common method of BoNT detection is the mouse bioassay. While this assay is sensitive, it is slow, quite expensive, has limited throughput and requires sacrificing animals. Herein, we discuss and compare recently developed alternative in vitro detection methods and assess their ability to supplement or replace the mouse bioassay in the analysis of complex matrix samples. Full article
(This article belongs to the Special Issue Neurotoxins of Biological Origin)
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2695 KiB  
Review
Structure and Function of Snake Venom Proteins Affecting Platelet Plug Formation
by Taei Matsui, Jiharu Hamako and Koiti Titani
Toxins 2010, 2(1), 10-23; https://doi.org/10.3390/toxins2010010 - 28 Dec 2009
Cited by 16 | Viewed by 14062
Abstract
Many snake venom proteins have been isolated that affect platelet plug formation by interacting either with platelet integrins, membrane glycoprotein Ib (GPIb), or plasma von Willebrand factor (VWF). Among them, disintegrins purified from various snake venoms are strong inhibitors of platelet aggregation. Botrocetin [...] Read more.
Many snake venom proteins have been isolated that affect platelet plug formation by interacting either with platelet integrins, membrane glycoprotein Ib (GPIb), or plasma von Willebrand factor (VWF). Among them, disintegrins purified from various snake venoms are strong inhibitors of platelet aggregation. Botrocetin and bitiscetin derived from Bothrops jararaca and Bitis arietans venom, respectively, induce VWF-dependent platelet agglutination in vitro. Several GPIb-binding proteins have also been isolated from snake venoms. In this review, we focus on the structure and function of those snake venom proteins that influence platelet plug formation. These proteins are potentially useful as reagents for the sub-diagnosis of platelet disorder or von Willebrand disease, as well as for clinical and basic research of thrombosis and hemostasis. Full article
(This article belongs to the Special Issue Animal Venoms)
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Article
Protein Domain Analysis of C. botulinum Type A Neurotoxin and Its Relationship with Other Botulinum Serotypes
by Shashi K. Sharma, Uma Basavanna and Hem D. Shukla
Toxins 2010, 2(1), 1-9; https://doi.org/10.3390/toxins2010001 - 24 Dec 2009
Cited by 4 | Viewed by 11532
Abstract
Botulinum neurotoxins (BoNTs) are highly potent poisons produced by seven serotypes of Clostridium botulinum. The mechanism of neurotoxin action is a multistep process which leads to the cleavage of one of three different SNARE proteins essential for synaptic vesicle fusion and transmission [...] Read more.
Botulinum neurotoxins (BoNTs) are highly potent poisons produced by seven serotypes of Clostridium botulinum. The mechanism of neurotoxin action is a multistep process which leads to the cleavage of one of three different SNARE proteins essential for synaptic vesicle fusion and transmission of the nerve signals to muscles: synaptobrevin, syntaxin, or SNAP-25. In order to understand the precise mechanism of neurotoxin in a host, the domain structure of the neurotoxin was analyzed among different serotypes of C. botulinum. The results indicate that neurotoxins type A, C, D, E and F contain a coiled-coil domain while types B and type G neurotoxin do not. Interestingly, phylogenetic analysis based on neurotoxin sequences has further confirmed that serotypes B and G are closely related. These results suggest that neurotoxin has multi-domain structure, and coiled-coil domain plays an important role in oligomerisation of the neurotoxin. Domain analysis may help to identify effective antibodies to treat Botulinum toxin intoxication. Full article
(This article belongs to the Special Issue Neurotoxins of Biological Origin)
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