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Open AccessArticle Antibacterial Activity and Toxicity of Analogs of Scorpion Venom IsCT Peptides
Antibiotics 2017, 6(3), 13; doi:10.3390/antibiotics6030013
Received: 6 June 2017 / Revised: 19 June 2017 / Accepted: 26 June 2017 / Published: 28 June 2017
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Abstract
Seven analogs of the natural, α-helix peptides IsCT1 and IsCT2—found in the venom of scorpion Opithancatus Madagascariensis—have been synthesized and tested to compare their antibacterial and hemolytic activity against natural peptides. In general, results show that increasing hydrophobicity by substituting positions 5
[...] Read more.
Seven analogs of the natural, α-helix peptides IsCT1 and IsCT2—found in the venom of scorpion Opithancatus Madagascariensis—have been synthesized and tested to compare their antibacterial and hemolytic activity against natural peptides. In general, results show that increasing hydrophobicity by substituting positions 5 and 9 of the sequences with alanine, valine, and leucine, enhances antibacterial activity. However, this also increases hemolytic activity. The analog with an increased net positive charge from +1 to +3 produces moderate bacterial growth inhibition but also has high hemolytic activity. On the other hand, the analog with a negative net charge (−1) has low antibacterial properties but also no cytotoxicity under the tested conditions, a similar result was found for five of the seven studied analogs. Full article
(This article belongs to the Special Issue Antibiotic Synthesis)
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Open AccessArticle Emulsion-Based Intradermal Delivery of Melittin in Rats
Molecules 2017, 22(5), 836; doi:10.3390/molecules22050836
Received: 14 March 2017 / Revised: 16 May 2017 / Accepted: 16 May 2017 / Published: 19 May 2017
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Abstract
Bee venom (BV) has long been used as a traditional medicine. The aim of the present study was to formulate a BV emulsion with good rheological properties for dermal application and investigate the effect of formulation on the permeation of melittin through dermatomed
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Bee venom (BV) has long been used as a traditional medicine. The aim of the present study was to formulate a BV emulsion with good rheological properties for dermal application and investigate the effect of formulation on the permeation of melittin through dermatomed rat skin. A formulated emulsion containing 1% (w/v) BV was prepared. The emulsion was compared with distilled water (DW) and 25% (w/v) N-methyl-2-pyrrolidone (NMP) in DW. Permeation of melittin from aqueous solution through the dermatomed murine skin was evaluated using the Franz diffusion cells. Samples of receptor cells withdrawn at pre-determined time intervals were measured for melittin amount. After the permeation study, the same skin was used for melittin extraction. In addition, a known amount of melittin (5 μg/mL) was added to stratum corneum, epidermis, and dermis of the rat skin, and the amount of melittin was measured at pre-determined time points. The measurement of melittin from all samples was done with HPLC-MS/MS. No melittin was detected in the receptor phase at all time points in emulsion, DW, or NMP groups. When the amount of melittin was further analyzed in stratum corneum, epidermis, and dermis from the permeation study, melittin was still not detected. In an additional experiment, the amount of melittin added to all skin matrices was corrected against the amount of melittin recovered. While the total amount of melittin was retained in the stratum corneum, less than 10% of melittin remained in epidermis and dermis within 15 and 30 min, respectively. Skin microporation with BV emulsion facilitates the penetration of melittin across the stratum corneum into epidermis and dermis, where emulsified melittin could have been metabolized by locally-occurring enzymes. Full article
(This article belongs to the Special Issue Bioactive Natural Peptides As A Pipeline For Therapeutics)
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Open AccessFeature PaperArticle Insect-Active Toxins with Promiscuous Pharmacology from the African Theraphosid Spider Monocentropus balfouri
Toxins 2017, 9(5), 155; doi:10.3390/toxins9050155
Received: 28 March 2017 / Revised: 24 April 2017 / Accepted: 28 April 2017 / Published: 5 May 2017
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Abstract
Many chemical insecticides are becoming less efficacious due to rising resistance in pest species, which has created much interest in the development of new, eco-friendly bioinsecticides. Since insects are the primary prey of most spiders, their venoms are a rich source of insect-active
[...] Read more.
Many chemical insecticides are becoming less efficacious due to rising resistance in pest species, which has created much interest in the development of new, eco-friendly bioinsecticides. Since insects are the primary prey of most spiders, their venoms are a rich source of insect-active peptides that can be used as leads for new bioinsecticides or as tools to study molecular receptors that are insecticidal targets. In the present study, we isolated two insecticidal peptides, µ/ω-TRTX-Mb1a and -Mb1b, from venom of the African tarantula Monocentropus balfouri. Recombinant µ/ω-TRTX-Mb1a and -Mb1b paralyzed both Lucilia cuprina (Australian sheep blowfly) and Musca domestica (housefly), but neither peptide affected larvae of Helicoverpa armigera (cotton bollworms). Both peptides inhibited currents mediated by voltage-gated sodium (NaV) and calcium channels in Periplaneta americana (American cockroach) dorsal unpaired median neurons, and they also inhibited the cloned Blattella germanica (German cockroach) NaV channel (BgNaV1). An additional effect seen only with Mb1a on BgNaV1 was a delay in fast inactivation. Comparison of the NaV channel sequences of the tested insect species revealed that variations in the S1–S2 loops in the voltage sensor domains might underlie the differences in activity between different phyla. Full article
(This article belongs to the Section Animal Venoms)
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Open AccessArticle A Pharmacological Examination of the Cardiovascular Effects of Malayan Krait (Bungarus candidus) Venoms
Toxins 2017, 9(4), 122; doi:10.3390/toxins9040122
Received: 13 March 2017 / Revised: 23 March 2017 / Accepted: 24 March 2017 / Published: 29 March 2017
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Abstract
Cardiovascular effects (e.g., tachycardia, hypo- and/or hypertension) are often clinical outcomes of snake envenoming. Malayan krait (Bungarus candidus) envenoming has been reported to cause cardiovascular effects that may be related to abnormalities in parasympathetic activity. However, the exact mechanism for this
[...] Read more.
Cardiovascular effects (e.g., tachycardia, hypo- and/or hypertension) are often clinical outcomes of snake envenoming. Malayan krait (Bungarus candidus) envenoming has been reported to cause cardiovascular effects that may be related to abnormalities in parasympathetic activity. However, the exact mechanism for this effect has yet to be determined. In the present study, we investigated the in vivo and in vitro cardiovascular effects of B. candidus venoms from Southern (BC-S) and Northeastern (BC-NE) Thailand. SDS-PAGE analysis of venoms showed some differences in the protein profile of the venoms. B. candidus venoms (50 µg/kg–100 µg/kg, i.v.) caused dose-dependent hypotension in anaesthetised rats. The highest dose caused sudden hypotension (phase I) followed by a return of mean arterial pressure to baseline levels and a decrease in heart rate with transient hypertension (phase II) prior to a small decrease in blood pressure (phase III). Prior administration of monovalent antivenom significantly attenuated the hypotension induced by venoms (100 µg/kg, i.v.). The sudden hypotensive effect of BC-NE venom was abolished by prior administration of hexamethonium (10 mg/kg, i.v.) or atropine (5 mg/kg, i.v.). BC-S and BC-NE venoms (0.1 µg/kg–100 µg/ml) induced concentration-dependent relaxation (EC50 = 8 ± 1 and 13 ± 3 µg/mL, respectively) in endothelium-intact aorta. The concentration–response curves were markedly shifted to the right by pre-incubation with L-NAME (0.2 mM), or removal of the endothelium, suggesting that endothelium-derived nitric oxide (NO) is likely to be responsible for venom-induced aortic relaxation. Our data indicate that the cardiovascular effects caused by B. candidus venoms may be due to a combination of vascular mediators (i.e., NO) and autonomic adaptation via nicotinic and muscarinic acetylcholine receptors. Full article
(This article belongs to the Section Animal Venoms)
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Open AccessArticle Toxin Fused with SUMO Tag: A New Expression Vector Strategy to Obtain Recombinant Venom Toxins with Easy Tag Removal inside the Bacteria
Toxins 2017, 9(3), 82; doi:10.3390/toxins9030082
Received: 11 January 2017 / Revised: 16 February 2017 / Accepted: 22 February 2017 / Published: 27 February 2017
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Abstract
Many animal toxins may target the same molecules that need to be controlled in certain pathologies; therefore, some toxins have led to the formulation of drugs that are presently used, and many other drugs are still under development. Nevertheless, collecting sufficient toxins from
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Many animal toxins may target the same molecules that need to be controlled in certain pathologies; therefore, some toxins have led to the formulation of drugs that are presently used, and many other drugs are still under development. Nevertheless, collecting sufficient toxins from the original source might be a limiting factor in studying their biological activities. Thus, molecular biology techniques have been applied in order to obtain large amounts of recombinant toxins into Escherichia coli. However, most animal toxins are difficult to express in this system, which results in insoluble, misfolded, or unstable proteins. To solve these issues, toxins have been fused with tags that may improve protein expression, solubility, and stability. Among these tags, the SUMO (small ubiquitin-related modifier) has been shown to be very efficient and can be removed by the Ulp1 protease. However, removing SUMO is a labor- and time-consuming process. To enhance this system, here we show the construction of a bicistronic vector that allows the expression of any protein fused to both the SUMO and Ulp1 protease. In this way, after expression, Ulp1 is able to cleave SUMO and leave the protein interest-free and ready for purification. This strategy was validated through the expression of a new phospholipase D from the spider Loxosceles gaucho and a disintegrin from the Bothrops insularis snake. Both recombinant toxins showed good yield and preserved biological activities, indicating that the bicistronic vector may be a viable method to produce proteins that are difficult to express. Full article
(This article belongs to the Section Animal Venoms)
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Open AccessEditorial Understanding the Snake Venom Metalloproteinases: An Interview with Jay Fox and José María Gutiérrez
Toxins 2017, 9(1), 33; doi:10.3390/toxins9010033
Received: 3 January 2017 / Accepted: 11 January 2017 / Published: 16 January 2017
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Abstract
Jay W. Fox and José María Gutiérrez recently finished editing a Special Issue on the topic “Snake Venom Metalloproteinases” in Toxins. The Special Issue covers a wide range of topics, including the molecular evolution and structure of snake venom metalloproteinases (SVMPs), the
[...] Read more.
Jay W. Fox and José María Gutiérrez recently finished editing a Special Issue on the topic “Snake Venom Metalloproteinases” in Toxins. The Special Issue covers a wide range of topics, including the molecular evolution and structure of snake venom metalloproteinases (SVMPs), the mechanisms involved in the generation of diversity of SVMPs, the mechanism of action of SVMPs, and their role in the pathophysiology of envenomings, with implications for improving the therapy of envenomings. In this interview, we discussed with Jay W. Fox and José María Gutiérrez their research on the SVMPs and their perspectives on the future trends and challenges for studying snake venoms. Full article
(This article belongs to the Special Issue Snake Venom Metalloproteinases) Printed Edition available
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Open AccessArticle A Novel Toxin from Haplopelma lividum Selectively Inhibits the NaV1.8 Channel and Possesses Potent Analgesic Efficacy
Toxins 2017, 9(1), 7; doi:10.3390/toxins9010007
Received: 15 October 2016 / Revised: 16 December 2016 / Accepted: 19 December 2016 / Published: 26 December 2016
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Abstract
Spider venoms are a complex mixture of peptides with a large number of neurotoxins targeting ion channels. Although thousands of peptide toxins have been identified from venoms of numerous species of spiders, many unknown species urgently need to be investigated. In this study,
[...] Read more.
Spider venoms are a complex mixture of peptides with a large number of neurotoxins targeting ion channels. Although thousands of peptide toxins have been identified from venoms of numerous species of spiders, many unknown species urgently need to be investigated. In this study, a novel sodium channel inhibitor, µ-TRTX-Hl1a, was identified from the venom of Haplopelma lividum. It contained eight cysteines and formed a conserved cysteine pattern of ICK motif. µ-TRTX-Hl1a inhibited the TTX-resistant (TTX-r) sodium channel current rather than the TTX-sensitive (TTX-s) sodium channel current. Meanwhile, µ-TRTX-Hl1a selectively inhibited NaV1.8 with an IC50 value of 2.19 μM. Intraperitoneal injection of µ-TRTX-Hl1a dose-dependently reduced inflammatory and neuropathic pain in rodent models of formalin-induced paw licking, tail-flicking, acetic acid-induced writhing, and hot plate test. It showed a better analgesic effect than morphine in inflammatory pain and equipotent effect to morphine in neuropathic pain. These findings demonstrate that µ-TRTX-Hl1a might be a valuable tool for physiology studies on NaV1.8 and a promising lead molecule for pain therapeutics. Full article
(This article belongs to the Section Animal Venoms)
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Open AccessReview Current Controversies in Lupus Anticoagulant Detection
Antibodies 2016, 5(4), 22; doi:10.3390/antib5040022
Received: 27 September 2016 / Revised: 17 November 2016 / Accepted: 18 November 2016 / Published: 2 December 2016
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Abstract
Antiphospholipid syndrome is an autoimmune, acquired thrombophilia diagnosed when vascular thrombosis or pregnancy morbidity are accompanied by persistent antiphospholipid antibodies. Lupus anticoagulants (LA) are one of the criteria antibodies but calibration plasmas are unavailable and they are detected by inference based on antibody
[...] Read more.
Antiphospholipid syndrome is an autoimmune, acquired thrombophilia diagnosed when vascular thrombosis or pregnancy morbidity are accompanied by persistent antiphospholipid antibodies. Lupus anticoagulants (LA) are one of the criteria antibodies but calibration plasmas are unavailable and they are detected by inference based on antibody behaviour in a medley of coagulation-based assays. Elevated screening tests suggest the presence of a LA, which is confirmed with mixing tests to evidence inhibition and confirmatory tests to demonstrate phospholipid-dependence. At least two screening tests of different principle must be used to account for antibody heterogeneity and controversy exists on whether assays, in addition to dilute Russell’s viper venom time and activated partial thromboplastin time, should be employed. A variety of approaches to raw data manipulation and interpretation attract debate, as does inclusion or exclusion of mixing studies in circumstances where the presence of a LA is already evident from other results. Therapeutic anticoagulation compromises coagulation-based assays but careful data interpretation and use of alternative reagents can detect or exclude LA in specific circumstances, and this aspect of LA detection continues to evolve. This review focuses on the main areas of debate in LA detection. Full article
(This article belongs to the Special Issue Antiphospholipid Antibodies and Syndrome)
Open AccessArticle Hydrostatin-TL1, an Anti-Inflammatory Active Peptide from the Venom Gland of Hydrophis cyanocinctus in the South China Sea
Int. J. Mol. Sci. 2016, 17(11), 1940; doi:10.3390/ijms17111940
Received: 22 September 2016 / Revised: 31 October 2016 / Accepted: 14 November 2016 / Published: 22 November 2016
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Abstract
Tumor necrosis factor (TNF)-α is a pleiotropic cytokine with intense pro-inflammatory and immunomodulatory properties, and anti-TNF-α biologics are effective therapies for various inflammatory diseases such as inflammatory bowel disease (IBD) and sepsis. Snake venom, as a traditional Chinese medicine, has been used in
[...] Read more.
Tumor necrosis factor (TNF)-α is a pleiotropic cytokine with intense pro-inflammatory and immunomodulatory properties, and anti-TNF-α biologics are effective therapies for various inflammatory diseases such as inflammatory bowel disease (IBD) and sepsis. Snake venom, as a traditional Chinese medicine, has been used in the treatment of inflammatory diseases in China for centuries. In this research, we constructed a venom gland T7 phage display library of the sea snake Hydrophis cyanocinctus to screen bioactive compounds that antagonize TNF-α and identified a novel nine-amino-acid peptide, termed hydrostatin-TL1 (H-TL1). In enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR) analyses, H-TL1 inhibited the interaction between TNF-α and TNF receptor 1 (TNFR1). Further, H-TL1 attenuated the cytotoxicity of TNF-α in L929 cells as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. H-TL1 also decreased the mRNA expression of TNF-α/TNFR1 downstream targets and suppressed the phosphorylation of well-characterized proteins of downstream signal transduction pathways in HEK-293 cells. In vivo data demonstrated that H-TL1 protects animals against dextran sodium sulfate (DSS)-induced acute colitis and lipopolysaccharide (LPS)-induced acute shock. Given its significant anti-inflammatory activity in vitro and in vivo, H-TL1 is a potential peptide for the development of new agents to treat TNF-α-associated inflammatory diseases. Full article
(This article belongs to the Section Biochemistry, Molecular and Cellular Biology)
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Open AccessArticle Structural and Functional Elucidation of Peptide Ts11 Shows Evidence of a Novel Subfamily of Scorpion Venom Toxins
Toxins 2016, 8(10), 288; doi:10.3390/toxins8100288
Received: 26 July 2016 / Revised: 25 September 2016 / Accepted: 26 September 2016 / Published: 30 September 2016
Cited by 1 | Viewed by 816 | PDF Full-text (3738 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
To date, several families of peptide toxins specifically interacting with ion channels in scorpion venom have been described. One of these families comprise peptide toxins (called KTxs), known to modulate potassium channels. Thus far, 202 KTxs have been reported, belonging to several subfamilies
[...] Read more.
To date, several families of peptide toxins specifically interacting with ion channels in scorpion venom have been described. One of these families comprise peptide toxins (called KTxs), known to modulate potassium channels. Thus far, 202 KTxs have been reported, belonging to several subfamilies of KTxs (called α, β, γ, κ, δ, and λ-KTxs). Here we report on a previously described orphan toxin from Tityus serrulatus venom, named Ts11. We carried out an in-depth structure-function analysis combining 3D structure elucidation of Ts11 and electrophysiological characterization of the toxin. The Ts11 structure is highlighted by an Inhibitor Cystine Knot (ICK) type scaffold, completely devoid of the classical secondary structure elements (α-helix and/or β-strand). This has, to the best of our knowledge, never been described before for scorpion toxins and therefore represents a novel, 6th type of structural fold for these scorpion peptides. On the basis of their preferred interaction with voltage-gated K channels, as compared to all the other targets tested, it can be postulated that Ts11 is the first member of a new subfamily, designated as ε-KTx. Full article
(This article belongs to the Section Animal Venoms)
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Open AccessArticle Protective Effects of Intratracheally-Administered Bee Venom Phospholipase A2 on Ovalbumin-Induced Allergic Asthma in Mice
Toxins 2016, 8(10), 269; doi:10.3390/toxins8100269
Received: 14 June 2016 / Accepted: 14 September 2016 / Published: 22 September 2016
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Abstract
Asthma is a common chronic disease characterized by bronchial inflammation, reversible airway obstruction, and airway hyperresponsiveness (AHR). Current therapeutic options for the management of asthma include inhaled corticosteroids and β2 agonists, which elicit harmful side effects. In the present study, we examined the
[...] Read more.
Asthma is a common chronic disease characterized by bronchial inflammation, reversible airway obstruction, and airway hyperresponsiveness (AHR). Current therapeutic options for the management of asthma include inhaled corticosteroids and β2 agonists, which elicit harmful side effects. In the present study, we examined the capacity of phospholipase A2 (PLA2), one of the major components of bee venom (BV), to reduce airway inflammation and improve lung function in an experimental model of asthma. Allergic asthma was induced in female BALB/c mice by intraperitoneal administration of ovalbumin (OVA) on days 0 and 14, followed by intratracheal challenge with 1% OVA six times between days 22 and 30. The infiltration of immune cells, such as Th2 cytokines in the lungs, and the lung histology, were assessed in the OVA-challenged mice in the presence and absence of an intratracheal administration of bvPLA2. We showed that the intratracheal administration of bvPLA2 markedly suppressed the OVA-induced allergic airway inflammation by reducing AHR, overall area of inflammation, and goblet cell hyperplasia. Furthermore, the suppression was associated with a significant decrease in the production of Th2 cytokines, such as IL-4, IL-5, and IL-13, and a reduction in the number of total cells, including eosinophils, macrophages, and neutrophils in the airway. Full article
(This article belongs to the Section Animal Venoms)
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Open AccessArticle Interaction between TNF and BmooMP-Alpha-I, a Zinc Metalloprotease Derived from Bothrops moojeni Snake Venom, Promotes Direct Proteolysis of This Cytokine: Molecular Modeling and Docking at a Glance
Toxins 2016, 8(7), 223; doi:10.3390/toxins8070223
Received: 17 December 2015 / Revised: 4 July 2016 / Accepted: 7 July 2016 / Published: 20 July 2016
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Abstract
Tumor necrosis factor (TNF) is a major cytokine in inflammatory processes and its deregulation plays a pivotal role in several diseases. Here, we report that a zinc metalloprotease extracted from Bothrops moojeni venom (BmooMP-alpha-I) inhibits TNF directly by promoting its degradation. This inhibition
[...] Read more.
Tumor necrosis factor (TNF) is a major cytokine in inflammatory processes and its deregulation plays a pivotal role in several diseases. Here, we report that a zinc metalloprotease extracted from Bothrops moojeni venom (BmooMP-alpha-I) inhibits TNF directly by promoting its degradation. This inhibition was demonstrated by both in vitro and in vivo assays, using known TLR ligands. These findings are supported by molecular docking results, which reveal interaction between BmooMP-alpha-I and TNF. The major cluster of interaction between BmooMP-alpha-I and TNF was confirmed by the structural alignment presenting Ligand Root Mean Square Deviation LRMS = 1.05 Å and Interactive Root Mean Square Deviation IRMS = 1.01 Å, this result being compatible with an accurate complex. Additionally, we demonstrated that the effect of this metalloprotease on TNF is independent of cell cytotoxicity and it does not affect other TLR-triggered cytokines, such as IL-12. Together, these results indicate that this zinc metalloprotease is a potential tool to be further investigated for the treatment of inflammatory disorders involving TNF deregulation. Full article
(This article belongs to the Special Issue Venomics, Venom Proteomics and Venom Transcriptomics)
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Open AccessArticle Activity of Palythoa caribaeorum Venom on Voltage-Gated Ion Channels in Mammalian Superior Cervical Ganglion Neurons
Toxins 2016, 8(5), 135; doi:10.3390/toxins8050135
Received: 10 March 2016 / Revised: 19 April 2016 / Accepted: 28 April 2016 / Published: 5 May 2016
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Abstract
The Zoanthids are an order of cnidarians whose venoms and toxins have been poorly studied. Palythoa caribaeorum is a zoanthid commonly found around the Mexican coastline. In this study, we tested the activity of P. caribaeorum venom on voltage-gated sodium channel (NaV
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The Zoanthids are an order of cnidarians whose venoms and toxins have been poorly studied. Palythoa caribaeorum is a zoanthid commonly found around the Mexican coastline. In this study, we tested the activity of P. caribaeorum venom on voltage-gated sodium channel (NaV1.7), voltage-gated calcium channel (CaV2.2), the A-type transient outward (IA) and delayed rectifier (IDR) currents of KV channels of the superior cervical ganglion (SCG) neurons of the rat. These results showed that the venom reversibly delays the inactivation process of voltage-gated sodium channels and inhibits voltage-gated calcium and potassium channels in this mammalian model. The compounds responsible for these effects seem to be low molecular weight peptides. Together, these results provide evidence for the potential use of zoanthids as a novel source of cnidarian toxins active on voltage-gated ion channels. Full article
(This article belongs to the Special Issue Animal Toxins and Biological Ion Channels)
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Open AccessArticle Prediction of Toxin Genes from Chinese Yellow Catfish Based on Transcriptomic and Proteomic Sequencing
Int. J. Mol. Sci. 2016, 17(4), 556; doi:10.3390/ijms17040556
Received: 14 March 2016 / Revised: 6 April 2016 / Accepted: 7 April 2016 / Published: 13 April 2016
Cited by 2 | Viewed by 914 | PDF Full-text (7544 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Fish venom remains a virtually untapped resource. There are so few fish toxin sequences for reference, which increases the difficulty to study toxins from venomous fish and to develop efficient and fast methods to dig out toxin genes or proteins. Here, we utilized
[...] Read more.
Fish venom remains a virtually untapped resource. There are so few fish toxin sequences for reference, which increases the difficulty to study toxins from venomous fish and to develop efficient and fast methods to dig out toxin genes or proteins. Here, we utilized Chinese yellow catfish (Pelteobagrus fulvidraco) as our research object, since it is a representative species in Siluriformes with its venom glands embedded in the pectoral and dorsal fins. In this study, we set up an in-house toxin database and a novel toxin-discovering protocol to dig out precise toxin genes by combination of transcriptomic and proteomic sequencing. Finally, we obtained 15 putative toxin proteins distributed in five groups, namely Veficolin, Ink toxin, Adamalysin, Za2G and CRISP toxin. It seems that we have developed a novel bioinformatics method, through which we could identify toxin proteins with high confidence. Meanwhile, these toxins can also be useful for comparative studies in other fish and development of potential drugs. Full article
(This article belongs to the Special Issue Fish Molecular Biology)
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Open AccessArticle Biodistribution and Lymphatic Tracking of the Main Neurotoxin of Micrurus fulvius Venom by Molecular Imaging
Toxins 2016, 8(4), 85; doi:10.3390/toxins8040085
Received: 16 February 2016 / Revised: 16 March 2016 / Accepted: 16 March 2016 / Published: 26 March 2016
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Abstract
The venom of the Eastern coral snake Micrurus fulvius can cause respiratory paralysis in the bitten patient, which is attributable to β-neurotoxins (β-NTx). The aim of this work was to study the biodistribution and lymphatic tracking by molecular imaging of the main β-NTx
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The venom of the Eastern coral snake Micrurus fulvius can cause respiratory paralysis in the bitten patient, which is attributable to β-neurotoxins (β-NTx). The aim of this work was to study the biodistribution and lymphatic tracking by molecular imaging of the main β-NTx of M. fulvius venom. β-NTx was bioconjugated with the chelator diethylenetriaminepenta-acetic acid (DTPA) and radiolabeled with the radionuclide Gallium-67. Radiolabeling efficiency was 60%–78%; radiochemical purity ≥92%; and stability at 48 h ≥ 85%. The median lethal dose (LD50) and PLA2 activity of bioconjugated β-NTx decreased 3 and 2.5 times, respectively, in comparison with native β-NTx. The immune recognition by polyclonal antibodies decreased 10 times. Biodistribution of β-NTx-DTPA-67Ga in rats showed increased uptake in popliteal, lumbar nodes and kidneys that was not observed with 67Ga-free. Accumulation in organs at 24 h was less than 1%, except for kidneys, where the average was 3.7%. The inoculation site works as a depot, since 10% of the initial dose of β-NTx-DTPA-67Ga remains there for up to 48 h. This work clearly demonstrates the lymphatic system participation in the biodistribution of β-NTx-DTPA-67Ga. Our approach could be applied to analyze the role of the lymphatic system in snakebite for a better understanding of envenoming. Full article
(This article belongs to the Section Animal Venoms)
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Open AccessArticle Apoptosis Activation in Human Lung Cancer Cell Lines by a Novel Synthetic Peptide Derived from Conus californicus Venom
Toxins 2016, 8(2), 38; doi:10.3390/toxins8020038
Received: 28 November 2015 / Revised: 26 January 2016 / Accepted: 28 January 2016 / Published: 5 February 2016
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Abstract
Lung cancer is one of the most common types of cancer in men and women and a leading cause of death worldwide resulting in more than one million deaths per year. The venom of marine snails Conus contains up to 200 pharmacologically active
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Lung cancer is one of the most common types of cancer in men and women and a leading cause of death worldwide resulting in more than one million deaths per year. The venom of marine snails Conus contains up to 200 pharmacologically active compounds that target several receptors in the cell membrane. Due to their diversity and specific binding properties, Conus toxins hold great potential as source of new drugs against cancer. We analyzed the cytotoxic effect of a 17-amino acid synthetic peptide (s-cal14.1a) that is based on a native toxin (cal14.1a) isolated from the sea snail Conus californicus. Cytotoxicity studies in four lung cancer cell lines were complemented with measurement of gene expression of apoptosis-related proteins Bcl-2, BAX and the pro-survival proteins NFκB-1 and COX-2, as well as quantification of caspase activity. Our results showed that H1299 and H1437 cell lines treated with s-call4.1a had decreased cell viability, activated caspases, and reduced expression of the pro-survival protein NFκB-1. To our knowledge, this is the first report describing activation of apoptosis in human lung cancer cell lines by s-cal14.1a and we offer insight into the possible mechanism of action. Full article
(This article belongs to the Special Issue Conotoxins: Novel Pharmacologies for Nervous System Disorders)
Open AccessArticle Structure-Activity Relationship of Chlorotoxin-Like Peptides
Toxins 2016, 8(2), 36; doi:10.3390/toxins8020036
Received: 2 November 2015 / Revised: 18 January 2016 / Accepted: 19 January 2016 / Published: 2 February 2016
Cited by 4 | Viewed by 1031 | PDF Full-text (2792 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Animal venom (e.g., scorpion) is a rich source of various protein and peptide toxins with diverse physio-/pharmaco-logical activities, which generally exert their action via target-specific modulation of different ion channel functions. Scorpion venoms are among the most widely-known source of peptidyl neurotoxins used
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Animal venom (e.g., scorpion) is a rich source of various protein and peptide toxins with diverse physio-/pharmaco-logical activities, which generally exert their action via target-specific modulation of different ion channel functions. Scorpion venoms are among the most widely-known source of peptidyl neurotoxins used for callipering different ion channels, such as; Na+, K+, Ca+, Cl, etc. A new peptide of the chlorotoxin family (i.e., Bs-Tx7) has been isolated, sequenced and synthesized from scorpion Buthus sindicus (family Buthidae) venom. This peptide demonstrates 66% with chlorotoxin (ClTx) and 82% with CFTR channel inhibitor (GaTx1) sequence identities reported from Leiurus quinquestriatus hebraeus venom. The toxin has a molecular mass of 3821 Da and possesses four intra-chain disulphide bonds. Amino acid sequence analysis of Bs-Tx7 revealed the presence of a scissile peptide bond (i.e., Gly-Ile) for human MMP2, whose activity is increased in the case of tumour malignancy. The effect of hMMP2 on Bs-Tx7, or vice versa, observed using the FRET peptide substrate with methoxycoumarin (Mca)/dinitrophenyl (Dnp) as fluorophore/quencher, designed and synthesized to obtain the lowest Km value for this substrate, showed approximately a 60% increase in the activity of hMMP2 upon incubation of Bs-Tx7 with the enzyme at a micromolar concentration (4 µM), indicating the importance of this toxin in diseases associated with decreased MMP2 activity. Full article
(This article belongs to the Special Issue Animal Toxins and Biological Ion Channels)
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Open AccessReview Computational Studies of Venom Peptides Targeting Potassium Channels
Toxins 2015, 7(12), 5194-5211; doi:10.3390/toxins7124877
Received: 15 October 2015 / Revised: 13 November 2015 / Accepted: 20 November 2015 / Published: 1 December 2015
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Abstract
Small peptides isolated from the venom of animals are potential scaffolds for ion channel drug discovery. This review article mainly focuses on the computational studies that have advanced our understanding of how various toxins interfere with the function of K+ channels. We
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Small peptides isolated from the venom of animals are potential scaffolds for ion channel drug discovery. This review article mainly focuses on the computational studies that have advanced our understanding of how various toxins interfere with the function of K+ channels. We introduce the computational tools available for the study of toxin-channel interactions. We then discuss how these computational tools have been fruitfully applied to elucidate the mechanisms of action of a wide range of venom peptides from scorpions, spiders, and sea anemone. Full article
(This article belongs to the Special Issue Animal Toxins and Biological Ion Channels)
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Open AccessReview Centipede Venoms and Their Components: Resources for Potential Therapeutic Applications
Toxins 2015, 7(11), 4832-4851; doi:10.3390/toxins7114832
Received: 14 October 2015 / Revised: 10 November 2015 / Accepted: 11 November 2015 / Published: 17 November 2015
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Abstract
Venomous animals have evolved with sophisticated bio-chemical strategies to arrest prey and defend themselves from natural predators. In recent years, peptide toxins from venomous animals have drawn considerable attention from researchers due to their surprising chemical, biochemical, and pharmacological diversity. Similar to other
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Venomous animals have evolved with sophisticated bio-chemical strategies to arrest prey and defend themselves from natural predators. In recent years, peptide toxins from venomous animals have drawn considerable attention from researchers due to their surprising chemical, biochemical, and pharmacological diversity. Similar to other venomous animals, centipedes are one of the crucial venomous arthropods that have been used in traditional medicine for hundreds of years in China. Despite signifying pharmacological importance, very little is known about the active components of centipede venoms. More than 500 peptide sequences have been reported in centipede venomous glands by transcriptome analysis, but only a small number of peptide toxins from centipede has been functionally described. Like other venomous animals such as snakes, scorpions, and spiders, the venom of centipedes could be an excellent source of peptides for developing drugs for treatments as well as bio-insecticides for agrochemical applications. Although centipede venoms are yet to be adequately studied, the venom of centipedes as well as their components described to date, should be compiled to help further research. Therefore, based on previous reports, this review focusses on findings and possible therapeutic applications of centipede venoms as well as their components. Full article
(This article belongs to the Special Issue Arthropod Venoms)
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Open AccessReview Pharmacological Alternatives for the Treatment of Neurodegenerative Disorders: Wasp and Bee Venoms and Their Components as New Neuroactive Tools
Toxins 2015, 7(8), 3179-3209; doi:10.3390/toxins7083179
Received: 15 May 2015 / Revised: 1 August 2015 / Accepted: 5 August 2015 / Published: 18 August 2015
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Abstract
Neurodegenerative diseases are relentlessly progressive, severely impacting affected patients, families and society as a whole. Increased life expectancy has made these diseases more common worldwide. Unfortunately, available drugs have insufficient therapeutic effects on many subtypes of these intractable diseases, and adverse effects hamper
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Neurodegenerative diseases are relentlessly progressive, severely impacting affected patients, families and society as a whole. Increased life expectancy has made these diseases more common worldwide. Unfortunately, available drugs have insufficient therapeutic effects on many subtypes of these intractable diseases, and adverse effects hamper continued treatment. Wasp and bee venoms and their components are potential means of managing or reducing these effects and provide new alternatives for the control of neurodegenerative diseases. These venoms and their components are well-known and irrefutable sources of neuroprotectors or neuromodulators. In this respect, the present study reviews our current understanding of the mechanisms of action and future prospects regarding the use of new drugs derived from wasp and bee venom in the treatment of major neurodegenerative disorders, including Alzheimer’s Disease, Parkinson’s Disease, Epilepsy, Multiple Sclerosis and Amyotrophic Lateral Sclerosis. Full article
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Open AccessArticle Molecular Cloning and Functional Studies of Two Kazal-Type Serine Protease Inhibitors Specifically Expressed by Nasonia vitripennis Venom Apparatus
Toxins 2015, 7(8), 2888-2905; doi:10.3390/toxins7082888
Received: 13 May 2015 / Revised: 29 June 2015 / Accepted: 27 July 2015 / Published: 4 August 2015
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Abstract
Two cDNA sequences of Kazal-type serine protease inhibitors (KSPIs) in Nasonia vitripennis, NvKSPI-1 and NvKSPI-2, were characterized and their open reading frames (ORFs) were 198 and 264 bp, respectively. Both NvKSPI-1 and NvKSPI-2 contained a typical Kazal-type domain. Real-time quantitative PCR
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Two cDNA sequences of Kazal-type serine protease inhibitors (KSPIs) in Nasonia vitripennis, NvKSPI-1 and NvKSPI-2, were characterized and their open reading frames (ORFs) were 198 and 264 bp, respectively. Both NvKSPI-1 and NvKSPI-2 contained a typical Kazal-type domain. Real-time quantitative PCR (RT-qPCR) results revealed that NvKSPI-1 and NvKSPI-2 mRNAs were mostly detected specifically in the venom apparatus, while they were expressed at lower levels in the ovary and much lower levels in other tissues tested. In the venom apparatus, both NvKSPI-1 and NvKSPI-2 transcripts were highly expressed on the fourth day post eclosion and then declined gradually. The NvKSPI-1 and NvKSPI-2 genes were recombinantly expressed utilizing a pGEX-4T-2 vector, and the recombinant products fused with glutathione S-transferase were purified. Inhibition of recombinant GST-NvKSPI-1 and GST-NvKSPI-2 to three serine protease inhibitors (trypsin, chymotrypsin, and proteinase K) were tested and results showed that only NvKSPI-1 could inhibit the activity of trypsin. Meanwhile, we evaluated the influence of the recombinant GST-NvKSPI-1 and GST-NvKSPI-2 on the phenoloxidase (PO) activity and prophenoloxidase (PPO) activation of hemolymph from a host pupa, Musca domestica. Results showed PPO activation in host hemolymph was inhibited by both recombinant proteins; however, there was no significant inhibition on the PO activity. Our results suggested that NvKSPI-1 and NvKSPI-2 could inhibit PPO activation in host hemolymph and trypsin activity in vitro. Full article
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Open AccessArticle Revealing the Function and the Structural Model of Ts4: Insights into the “Non-Toxic” Toxin from Tityus serrulatus Venom
Toxins 2015, 7(7), 2534-2550; doi:10.3390/toxins7072534
Received: 20 May 2015 / Revised: 20 June 2015 / Accepted: 25 June 2015 / Published: 6 July 2015
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Abstract
The toxin, previously described as a “non-toxic” toxin, was isolated from the scorpion venom of Tityus serrulatus (Ts), responsible for the most severe and the highest number of accidents in Brazil. In this study, the subtype specificity and selectivity of Ts4 was investigated
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The toxin, previously described as a “non-toxic” toxin, was isolated from the scorpion venom of Tityus serrulatus (Ts), responsible for the most severe and the highest number of accidents in Brazil. In this study, the subtype specificity and selectivity of Ts4 was investigated using six mammalian Nav channels (Nav1.2→Nav1.6 and Nav1.8) and two insect Nav channels (DmNav1 and BgNav). The electrophysiological assays showed that Ts4 specifically inhibited the fast inactivation of Nav1.6 channels, the most abundant sodium channel expressed in the adult central nervous system, and can no longer be classified as a “non-toxic peptide”. Based on the results, we could classify the Ts4 as a classical α-toxin. The Ts4 3D-structural model was built based on the solved X-ray Ts1 3D-structure, the major toxin from Ts venom with which it shares high sequence identity (65.57%). The Ts4 model revealed a flattened triangular shape constituted by three-stranded antiparallel β-sheet and one α-helix stabilized by four disulfide bonds. The absence of a Lys in the first amino acid residue of the N-terminal of Ts4 is probably the main responsible for its low toxicity. Other key amino acid residues important to the toxicity of α- and β-toxins are discussed here. Full article
(This article belongs to the Special Issue Arthropod Venoms)
Open AccessArticle The Anti-Inflammatory Effects of the Methanolic Extract and Fractions from Davilla elliptica St. Hil. (Dilleniaceae) on Bothrops jararaca Envenomation
Int. J. Mol. Sci. 2015, 16(6), 12454-12466; doi:10.3390/ijms160612454
Received: 27 April 2015 / Revised: 19 May 2015 / Accepted: 19 May 2015 / Published: 2 June 2015
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Abstract
Inflammation and haemorrhage are the main characteristics of tissue injury in botropic envenomation. Although some studies have shown that anti-venom prevents systemic reactions, it is not efficient in preventing tissue injury at the site of the bite. Therefore, this work was undertaken to
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Inflammation and haemorrhage are the main characteristics of tissue injury in botropic envenomation. Although some studies have shown that anti-venom prevents systemic reactions, it is not efficient in preventing tissue injury at the site of the bite. Therefore, this work was undertaken to investigate the anti-inflammatory effects of the methanolic extract and fractions from D. elliptica and to evaluate the role of matrix metalloproteinases (MMPs) in this process. Effects of the extract and fractions from D. elliptica were evaluated using a carrageenan-induced paw oedema model in rats, and leukocyte rolling was visualized by intravital. The quantification of MMPs activities (MMP-2 and MMP-9) extracted from the dermis of mice treated with extract and fractions alone or incubated with venom was determined by zymographic analyses. Our results show that intraperitoneal (i.p.) injection of fractions significantly reduced paw oedema after the carrageenan challenge. Treatment with the tannins fraction also resulted in considerable inhibition of the rolling of leukocytes and this fraction was able to decrease the activation of MMP-9. These results confirmed the anti-inflammatory activity of the methanolic extract and tannins fraction of D. elliptica and showed that the dermonecrosis properties of B. jararaca venom might be mediated through the inhibition of MMP-9 activity. Full article
(This article belongs to the Special Issue Metalloproteins)
Open AccessArticle Influence of Honeybee Sting on Peptidome Profile in Human Serum
Toxins 2015, 7(5), 1808-1820; doi:10.3390/toxins7051808
Received: 31 March 2015 / Accepted: 15 May 2015 / Published: 22 May 2015
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Abstract
The aim of this study was to explore the serum peptide profiles from honeybee stung and non-stung individuals. Two groups of serum samples obtained from 27 beekeepers were included in our study. The first group of samples was collected within 3 h after
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The aim of this study was to explore the serum peptide profiles from honeybee stung and non-stung individuals. Two groups of serum samples obtained from 27 beekeepers were included in our study. The first group of samples was collected within 3 h after a bee sting (stung beekeepers), and the samples were collected from the same person a second time after at least six weeks after the last bee sting (non-stung beekeepers). Peptide profile spectra were determined using MALDI-TOF mass spectrometry combined with Omix, ZipTips and magnetic beads based on weak-cation exchange (MB-WCX) enrichment strategies in the mass range of 1–10 kDa. The samples were classified, and discriminative models were established by using the quick classifier, genetic algorithm and supervised neural network algorithms. All of the statistical algorithms used in this study allow distinguishing analyzed groups with high statistical significance, which confirms the influence of honeybee sting on the serum peptidome profile. The results of this study may broaden the understanding of the human organism’s response to honeybee venom. Due to the fact that our pilot study was carried out on relatively small datasets, it is necessary to conduct further proteomic research of the response to honeybee sting on a larger group of samples. Full article
Open AccessFeature PaperReview Natural Compounds Interacting with Nicotinic Acetylcholine Receptors: From Low-Molecular Weight Ones to Peptides and Proteins
Toxins 2015, 7(5), 1683-1701; doi:10.3390/toxins7051683
Received: 28 March 2015 / Accepted: 7 May 2015 / Published: 14 May 2015
Cited by 6 | Viewed by 1442 | PDF Full-text (811 KB) | HTML Full-text | XML Full-text
Abstract
Nicotinic acetylcholine receptors (nAChRs) fulfill a variety of functions making identification and analysis of nAChR subtypes a challenging task. Traditional instruments for nAChR research are d-tubocurarine, snake venom protein α-bungarotoxin (α-Bgt), and α-conotoxins, neurotoxic peptides from Conus snails. Various new compounds of different
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Nicotinic acetylcholine receptors (nAChRs) fulfill a variety of functions making identification and analysis of nAChR subtypes a challenging task. Traditional instruments for nAChR research are d-tubocurarine, snake venom protein α-bungarotoxin (α-Bgt), and α-conotoxins, neurotoxic peptides from Conus snails. Various new compounds of different structural classes also interacting with nAChRs have been recently identified. Among the low-molecular weight compounds are alkaloids pibocin, varacin and makaluvamines C and G. 6-Bromohypaphorine from the mollusk Hermissenda crassicornis does not bind to Torpedo nAChR but behaves as an agonist on human α7 nAChR. To get more selective α-conotoxins, computer modeling of their complexes with acetylcholine-binding proteins and distinct nAChRs was used. Several novel three-finger neurotoxins targeting nAChRs were described and α-Bgt inhibition of GABA-A receptors was discovered. Information on the mechanisms of nAChR interactions with the three-finger proteins of the Ly6 family was found. Snake venom phospholipases A2 were recently found to inhibit different nAChR subtypes. Blocking of nAChRs in Lymnaea stagnalis neurons was shown for venom C-type lectin-like proteins, appearing to be the largest molecules capable to interact with the receptor. A huge nAChR molecule sensible to conformational rearrangements accommodates diverse binding sites recognizable by structurally very different compounds. Full article
(This article belongs to the Special Issue Selected Papers from the 5th Venoms to Drugs Meeting)
Open AccessArticle The Finding of a Group IIE Phospholipase A2 Gene in a Specified Segment of Protobothrops flavoviridis Genome and Its Possible Evolutionary Relationship to Group IIA Phospholipase A2 Genes
Toxins 2014, 6(12), 3471-3487; doi:10.3390/toxins6123471
Received: 7 November 2014 / Revised: 5 December 2014 / Accepted: 15 December 2014 / Published: 18 December 2014
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Abstract
The genes encoding group IIE phospholipase A2, abbreviated as IIE PLA2, and its 5' and 3' flanking regions of Crotalinae snakes such as Protobothrops flavoviridis, P. tokarensis, P. elegans, and Ovophis okinavensis, were found and
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The genes encoding group IIE phospholipase A2, abbreviated as IIE PLA2, and its 5' and 3' flanking regions of Crotalinae snakes such as Protobothrops flavoviridis, P. tokarensis, P. elegans, and Ovophis okinavensis, were found and sequenced. The genes consisted of four exons and three introns and coded for 22 or 24 amino acid residues of the signal peptides and 134 amino acid residues of the mature proteins. These IIE PLA2s show high similarity to those from mammals and Colubridae snakes. The high expression level of IIE PLA2s in Crotalinae venom glands suggests that they should work as venomous proteins. The blast analysis indicated that the gene encoding OTUD3, which is ovarian tumor domain-containing protein 3, is located in the 3' downstream of IIE PLA2 gene. Moreover, a group IIA PLA2 gene was found in the 5' upstream of IIE PLA2 gene linked to the OTUD3 gene (OTUD3) in the P. flavoviridis genome. It became evident that the specified arrangement of IIA PLA2 gene, IIE PLA2 gene, and OTUD3 in this order is common in the genomes of humans to snakes. The present finding that the genes encoding various secretory PLA2s form a cluster in the genomes of humans to birds is closely related to the previous finding that six venom PLA2 isozyme genes are densely clustered in the so-called NIS-1 fragment of the P. flavoviridis genome. It is also suggested that venom IIA PLA2 genes may be evolutionarily derived from the IIE PLA2 gene. Full article
(This article belongs to the collection Evolution of Venom Systems)
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Open AccessArticle Intrahippocampal Infusion of Crotamine Isolated from Crotalus durissus terrificus Alters Plasma and Brain Biochemical Parameters
Int. J. Environ. Res. Public Health 2014, 11(11), 11438-11449; doi:10.3390/ijerph111111438
Received: 3 July 2014 / Revised: 21 October 2014 / Accepted: 21 October 2014 / Published: 5 November 2014
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Abstract
Crotamine is one of the main constituents of the venom of the South American rattlesnake Crotalus durissus terrificus. Here we sought to investigate the inflammatory and toxicological effects induced by the intrahippocampal administration of crotamine isolated from Crotalus whole venom. Adult rats
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Crotamine is one of the main constituents of the venom of the South American rattlesnake Crotalus durissus terrificus. Here we sought to investigate the inflammatory and toxicological effects induced by the intrahippocampal administration of crotamine isolated from Crotalus whole venom. Adult rats received an intrahippocampal infusion of crotamine or vehicle and were euthanized 24 h or 21 days after infusion. Plasma and brain tissue were collected for biochemical analysis. Complete blood count, creatinine, urea, glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), creatine-kinase (CK), creatine kinase-muscle B (CK-MB) and oxidative parameters (assessed by DNA damage and micronucleus frequency in leukocytes, lipid peroxidation and protein carbonyls in plasma and brain) were quantified. Unpaired and paired t-tests were used for comparisons between saline and crotamine groups, and within groups (24 h vs. 21 days), respectively. After 24 h crotamine infusion promoted an increase of urea, GOT, GPT, CK, and platelets values (p ≤ 0.01), while red blood cells, hematocrit and leukocytes values decreased (p ≤ 0.01). Additionally, 21 days after infusion crotamine group showed increased creatinine, leukocytes, TBARS (plasma and brain), carbonyl (plasma and brain) and micronucleus compared to the saline-group (p ≤ 0.01). Our findings show that crotamine infusion alter hematological parameters and cardiac markers, as well as oxidative parameters, not only in the brain, but also in the blood, indicating a systemic pro-inflammatory and toxicological activity. A further scientific attempt in terms of preserving the beneficial activity over toxicity is required. Full article
Open AccessArticle PhTX-II a Basic Myotoxic Phospholipase A2 from Porthidium hyoprora Snake Venom, Pharmacological Characterization and Amino Acid Sequence by Mass Spectrometry
Toxins 2014, 6(11), 3077-3097; doi:10.3390/toxins6113077
Received: 10 September 2014 / Revised: 16 October 2014 / Accepted: 21 October 2014 / Published: 31 October 2014
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Abstract
A monomeric basic PLA2 (PhTX-II) of 14149.08 Da molecular weight was purified to homogeneity from Porthidium hyoprora venom. Amino acid sequence by in tandem mass spectrometry revealed that PhTX-II belongs to Asp49 PLA2 enzyme class and displays conserved domains as the
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A monomeric basic PLA2 (PhTX-II) of 14149.08 Da molecular weight was purified to homogeneity from Porthidium hyoprora venom. Amino acid sequence by in tandem mass spectrometry revealed that PhTX-II belongs to Asp49 PLA2 enzyme class and displays conserved domains as the catalytic network, Ca2+-binding loop and the hydrophobic channel of access to the catalytic site, reflected in the high catalytic activity displayed by the enzyme. Moreover, PhTX-II PLA2 showed an allosteric behavior and its enzymatic activity was dependent on Ca2+. Examination of PhTX-II PLA2 by CD spectroscopy indicated a high content of alpha-helical structures, similar to the known structure of secreted phospholipase IIA group suggesting a similar folding. PhTX-II PLA2 causes neuromuscular blockade in avian neuromuscular preparations with a significant direct action on skeletal muscle function, as well as, induced local edema and myotoxicity, in mice. The treatment of PhTX-II by BPB resulted in complete loss of their catalytic activity that was accompanied by loss of their edematogenic effect. On the other hand, enzymatic activity of PhTX-II contributes to this neuromuscular blockade and local myotoxicity is dependent not only on enzymatic activity. These results show that PhTX-II is a myotoxic Asp49 PLA2 that contributes with toxic actions caused by P. hyoprora venom. Full article
(This article belongs to the Section Animal Venoms)
Open AccessArticle Okinalysin, a Novel P-I Metalloproteinase from Ovophis okinavensis: Biological Properties and Effect on Vascular Endothelial Cells
Toxins 2014, 6(9), 2594-2604; doi:10.3390/toxins6092594
Received: 18 July 2014 / Accepted: 18 August 2014 / Published: 25 August 2014
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Abstract
A novel hemorrhagic metalloproteinase, okinalysin, was isolated from the venom of Ovophis okinavensis. It possessed caseinolytic and hemorrhagic activities, and also hydrolyzed fibrinogen and collagen. These activities were inhibited by ethylenediaminetetraacetic acid (EDTA) but not by p-amidinophenyl methanesulfonyl fluoride hydrochloride (APMSF).
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A novel hemorrhagic metalloproteinase, okinalysin, was isolated from the venom of Ovophis okinavensis. It possessed caseinolytic and hemorrhagic activities, and also hydrolyzed fibrinogen and collagen. These activities were inhibited by ethylenediaminetetraacetic acid (EDTA) but not by p-amidinophenyl methanesulfonyl fluoride hydrochloride (APMSF). The molecular mass of okinalysin was 22,202 Da measured by MALDI/TOF mass spectrometry. The primary structure of okinalysin was partially determined by Edman sequencing, and the putative zinc-binding domain HEXXHXXGXXH was found to be present in its structure. From these data, okinalysin is defined as a metalloproteinase belonging to a P-I class. The partial amino acid sequence of okinalysin was homologous to the C-terminus of MP 10, a putative metalloproteinase induced from transcriptome of the venom gland cDNA sequencing of O. okinavensis. Okinalysin possessed cytotoxic activity on cultured endothelial cells, and the EC50 on human pulmonary artery endothelial cells was determined to be 0.6 μg/mL. The histopathological study also showed that okinalysin causes the leakage of red blood cells and neutrophil infiltration. These results indicate that destruction of blood vessels by okinalysin is one of the main causes of hemorrhage. Full article
(This article belongs to the Special Issue Antivenom and Venom Therapeutics)
Open AccessEditorial Scorpions: A Presentation
Toxins 2014, 6(7), 2137-2148; doi:10.3390/toxins6072137
Received: 20 December 2013 / Revised: 7 July 2014 / Accepted: 8 July 2014 / Published: 21 July 2014
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Abstract
Scorpions, at least the species of the family Buthidæ whose venoms are better known, appear as animals that have evolved very little over time. The composition of their venoms is relatively simple as most toxins have a common structural motif that is found
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Scorpions, at least the species of the family Buthidæ whose venoms are better known, appear as animals that have evolved very little over time. The composition of their venoms is relatively simple as most toxins have a common structural motif that is found in other venoms from primitive species. Moreover, all the scorpion venom toxins principally act on membrane ionic channels of excitable cells. The results of recent works lead to the conclusion that in scorpions there is a close relationship between venomous function and innate immune function both remarkably efficient. Full article
(This article belongs to the Special Issue Scorpion Toxins)
Open AccessArticle Characterization of a Novel Conus bandanus Conopeptide Belonging to the M-Superfamily Containing Bromotryptophan
Mar. Drugs 2014, 12(6), 3449-3465; doi:10.3390/md12063449
Received: 21 February 2014 / Revised: 7 March 2014 / Accepted: 22 May 2014 / Published: 5 June 2014
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Abstract
A novel conotoxin (conopeptide) was biochemically characterized from the crude venom of the molluscivorous marine snail, Conus bandanus (Hwass in Bruguière, 1792), collected in the south-central coast of Vietnam. The peptide was identified by screening bromotryptophan from chromatographic fractions of the crude venom.
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A novel conotoxin (conopeptide) was biochemically characterized from the crude venom of the molluscivorous marine snail, Conus bandanus (Hwass in Bruguière, 1792), collected in the south-central coast of Vietnam. The peptide was identified by screening bromotryptophan from chromatographic fractions of the crude venom. Tandem mass spectrometry techniques were used to detect and localize different post-translational modifications (PTMs) present in the BnIIID conopeptide. The sequence was confirmed by Edman’s degradation and mass spectrometry revealing that the purified BnIIID conopeptide had 15 amino acid residues, with six cysteines at positions 1, 2, 7, 11, 13, and 14, and three PTMs: bromotryptophan, γ-carboxy glutamate, and amidated aspartic acid, at positions “4”, “5”, and “15”, respectively. The BnIIID peptide was synthesized for comparison with the native peptide. Homology comparison with conopeptides having the III-cysteine framework (–CCx1x2x3x4Cx1x2x3Cx1CC–) revealed that BnIIID belongs to the M-1 family of conotoxins. This is the first report of a member of the M-superfamily containing bromotryptophan as PTM. Full article
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Open AccessArticle Enhanced Antimicrobial Activity of AamAP1-Lysine, a Novel Synthetic Peptide Analog Derived from the Scorpion Venom Peptide AamAP1
Pharmaceuticals 2014, 7(5), 502-516; doi:10.3390/ph7050502
Received: 7 March 2014 / Revised: 9 April 2014 / Accepted: 14 April 2014 / Published: 25 April 2014
Cited by 5 | Viewed by 2037 | PDF Full-text (307 KB) | HTML Full-text | XML Full-text
Abstract
There is great interest in the development of antimicrobial peptides as a potentially novel class of antimicrobial agents. Several structural determinants are responsible for the antimicrobial and cytolytic activity of antimicrobial peptides. In our study, a new synthetic peptide analog, AamAP1-Lysine from the
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There is great interest in the development of antimicrobial peptides as a potentially novel class of antimicrobial agents. Several structural determinants are responsible for the antimicrobial and cytolytic activity of antimicrobial peptides. In our study, a new synthetic peptide analog, AamAP1-Lysine from the naturally occurring scorpion venom antimicrobial peptide AamAP1, was designed by modifying the parent peptide in order to increase the positive charge and optimize other physico-chemical parameters involved in antimicrobial activity. AamAP1-Lysine displayed potent antibacterial activity against Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration was in the range of 5 to 15 µM with a 10 fold increase in potency over the parent peptide. The hemolytic and antiproliferative activity of AamAP1-Lysine against eukaryotic mammalian cells was minimal at the concentration range needed to inhibit bacterial growth. The antibacterial mechanism analysis indicated that AamAP1-Lysine is probably inducing bacterial cell death through membrane damage and permeabilization determined by the release of β-galactosidase enzyme from peptide treated E. coli cells. DNA binding studies revealed that AamAP1-Lysine caused complete retardation of DNA migration and could display intracellular activities in addition to the membrane permeabilization mode of action reported earlier. In conclusion, AamAP1-Lysine could prove to be a potential candidate for antimicrobial drug development in future studies. Full article
Open AccessArticle Electrophysiological Characterization of Ts6 and Ts7, K+ Channel Toxins Isolated through an Improved Tityus serrulatus Venom Purification Procedure
Toxins 2014, 6(3), 892-913; doi:10.3390/toxins6030892
Received: 12 December 2013 / Revised: 24 January 2014 / Accepted: 17 February 2014 / Published: 28 February 2014
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Abstract
In Brazil, Tityus serrulatus (Ts) is the species responsible for most of the scorpion related accidents. Among the Ts toxins, the neurotoxins with action on potassium channels (α-KTx) present high interest, due to their effect in the envenoming process and the ion channel
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In Brazil, Tityus serrulatus (Ts) is the species responsible for most of the scorpion related accidents. Among the Ts toxins, the neurotoxins with action on potassium channels (α-KTx) present high interest, due to their effect in the envenoming process and the ion channel specificity they display. The α-KTx toxins family is the most relevant because its toxins can be used as therapeutic tools for specific target cells. The improved isolation method provided toxins with high resolution, obtaining pure Ts6 and Ts7 in two chromatographic steps. The effects of Ts6 and Ts7 toxins were evaluated in 14 different types of potassium channels using the voltage-clamp technique with two-microelectrodes. Ts6 toxin shows high affinity for Kv1.2, Kv1.3 and Shaker IR, blocking these channels in low concentrations. Moreover, Ts6 blocks the Kv1.3 channel in picomolar concentrations with an IC50 of 0.55 nM and therefore could be of valuable assistance to further designing immunosuppressive therapeutics. Ts7 toxin blocks multiple subtypes channels, showing low selectivity among the channels analyzed. This work also stands out in its attempt to elucidate the residues important for interacting with each channel and, in the near future, to model a desired drug. Full article
(This article belongs to the Special Issue Scorpion Toxins)
Open AccessArticle Nerve Growth Factor from Cobra Venom Inhibits the Growth of Ehrlich Tumor in Mice
Toxins 2014, 6(3), 784-795; doi:10.3390/toxins6030784
Received: 12 November 2013 / Revised: 14 February 2014 / Accepted: 17 February 2014 / Published: 26 February 2014
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Abstract
The effects of nerve growth factor (NGF) from cobra venom (cvNGF) on growth of Ehrlich ascites carcinoma (EAC) cells inoculated subcutaneously in mice have been studied. The carcinoma growth slows down, but does not stop, during a course of cvNGF injections and restores
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The effects of nerve growth factor (NGF) from cobra venom (cvNGF) on growth of Ehrlich ascites carcinoma (EAC) cells inoculated subcutaneously in mice have been studied. The carcinoma growth slows down, but does not stop, during a course of cvNGF injections and restores after the course has been discontinued. The maximal anti-tumor effect has been observed at a dose of 8 nmoles cvNGF/kg body weight. cvNGF does not impact on lifespan of mice with grafted EAC cells. K252a, a tyrosine kinase inhibitor, attenuates the anti-tumor effect of cvNGF indicating the involvement of TrkA receptors in the process. cvNGF has induced also increase in body weight of the experimental animals. In overall, cvNGF shows the anti-tumor and weight-increasing effects which are opposite to those described for mammalian NGF (mNGF). However in experiments on breast cancer cell line MCF-7 cvNGF showed the same proliferative effects as mNGF and had no cytotoxic action on tumor cells in vitro. These data suggest that cvNGF slows down EAC growth via an indirect mechanism in which TrkA receptors are involved. Full article
(This article belongs to the Section Animal Venoms)
Open AccessArticle Expression of VEGF and Flk-1 and Flt-1 Receptors during Blood-Brain Barrier (BBB) Impairment Following Phoneutria nigriventer Spider Venom Exposure
Toxins 2013, 5(12), 2572-2588; doi:10.3390/toxins5122572
Received: 23 October 2013 / Revised: 30 November 2013 / Accepted: 3 December 2013 / Published: 18 December 2013
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Abstract
Apart from its angiogenic and vascular permeation activity, the vascular endothelial growth factor (VEGF) has been also reported as a potent neuronal protector. Newborn rats with low VEGF levels develop neuron degeneration, while high levels induce protective mechanisms in several neuropathological conditions. Phoneutria
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Apart from its angiogenic and vascular permeation activity, the vascular endothelial growth factor (VEGF) has been also reported as a potent neuronal protector. Newborn rats with low VEGF levels develop neuron degeneration, while high levels induce protective mechanisms in several neuropathological conditions. Phoneutria nigriventer spider venom (PNV) disrupts the blood-brain barrier (BBB) and causes neuroinflammation in central neurons along with excitotoxic signals in rats and humans. All these changes are transient. Herein, we examined the expression of VEGF and its receptors, Flt-1 and Flk-1 in the hippocampal neurons following envenomation by PNV. Adult and neonatal rats were evaluated at time limits of 2, 5 and 24 h. Additionally, BBB integrity was assessed by measuring the expression of occludin, β-catenin and laminin and neuron viability was evaluated by NeuN expression. VEGF, Flt-1 and Flk-1 levels increased in PNV-administered rats, concurrently with respective mRNAs. Flt-1 and Flk-1 immunolabeling was nuclear in neurons of hippocampal regions, instead of the VEGF membrane-bound typical location. These changes occurred simultaneously with the transient decreases in BBB-associated proteins and NeuN positivity. Adult rats showed more prominent expressional increases of the VEGF/Flt-1/Flk-1 system and earlier recovery of BBB-related proteins than neonates. We conclude that the reactive expressional changes seen here suggest that VEGF and receptors could have a role in the excitotoxic mechanism of PNV and that such role would be less efficient in neonate rats. Full article
Open AccessArticle Preliminary Results of the in Vivo and in Vitro Characterization of a Tentacle Venom Fraction from the Jellyfish Aurelia aurita
Toxins 2013, 5(12), 2420-2433; doi:10.3390/toxins5122420
Received: 9 October 2013 / Revised: 1 November 2013 / Accepted: 4 November 2013 / Published: 6 December 2013
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Abstract
The neurotoxic effects produced by a tentacle venom extract and a fraction were analyzed and correlated by in vivo and in vitro approaches. The tentacle venom extract exhibited a wide range of protein components (from 24 to >225 kDa) and produced tetanic reactions,
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The neurotoxic effects produced by a tentacle venom extract and a fraction were analyzed and correlated by in vivo and in vitro approaches. The tentacle venom extract exhibited a wide range of protein components (from 24 to >225 kDa) and produced tetanic reactions, flaccid paralysis, and death when injected into crabs. Two chromatography fractions also produced uncontrolled appendix movements and leg stretching. Further electrophysiological characterization demonstrated that one of these fractions potently inhibited ACh-elicited currents mediated by both vertebrate fetal and adult muscle nicotinic acetylcholine receptors (nAChR) subtypes. Receptor inhibition was concentration-dependent and completely reversible. The calculated IC50 values were 1.77 μg/μL for fetal and 2.28 μg/μL for adult muscle nAChRs. The bioactive fraction was composed of a major protein component at ~90 kDa and lacked phospholipase A activity. This work represents the first insight into the interaction of jellyfish venom components and muscle nicotinic receptors. Full article
(This article belongs to the collection Marine and Freshwater Toxins)
Open AccessArticle Molecular Cloning and Pharmacological Properties of an Acidic PLA2 from Bothrops pauloensis Snake Venom
Toxins 2013, 5(12), 2403-2419; doi:10.3390/toxins5122403
Received: 14 August 2013 / Revised: 13 November 2013 / Accepted: 21 November 2013 / Published: 4 December 2013
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Abstract
In this work, we describe the molecular cloning and pharmacological properties of an acidic phospholipase A2 (PLA2) isolated from Bothrops pauloensis snake venom. This enzyme, denominated BpPLA2-TXI, was purified by four chromatographic steps and represents 2.4% of
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In this work, we describe the molecular cloning and pharmacological properties of an acidic phospholipase A2 (PLA2) isolated from Bothrops pauloensis snake venom. This enzyme, denominated BpPLA2-TXI, was purified by four chromatographic steps and represents 2.4% of the total snake venom protein content. BpPLA2-TXI is a monomeric protein with a molecular mass of 13.6 kDa, as demonstrated by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) analysis and its theoretical isoelectric point was 4.98. BpPLA2-TXI was catalytically active and showed some pharmacological effects such as inhibition of platelet aggregation induced by collagen or ADP and also induced edema and myotoxicity. BpPLA2-TXI displayed low cytotoxicity on TG-180 (CCRF S 180 II) and Ovarian Carcinoma (OVCAR-3), whereas no cytotoxicity was found in regard to MEF (Mouse Embryonic Fibroblast) and Sarcoma 180 (TIB-66). The N-terminal sequence of forty-eight amino acid residues was determined by Edman degradation. In addition, the complete primary structure of 122 amino acids was deduced by cDNA from the total RNA of the venom gland using specific primers, and it was significantly similar to other acidic D49 PLA2s. The phylogenetic analyses showed that BpPLA2-TXI forms a group with other acidic D49 PLA2s from the gender Bothrops, which are characterized by a catalytic activity associated with anti-platelet effects. Full article
Open AccessArticle Molecular Characterization of Lys49 and Asp49 Phospholipases A2 from Snake Venom and Their Antiviral Activities against Dengue virus
Toxins 2013, 5(10), 1780-1798; doi:10.3390/toxins5101780
Received: 2 August 2013 / Revised: 11 September 2013 / Accepted: 26 September 2013 / Published: 15 October 2013
Cited by 9 | Viewed by 1912 | PDF Full-text (1177 KB) | HTML Full-text | XML Full-text
Abstract
We report the detailed molecular characterization of two PLA2s, Lys49 and Asp49 isolated from Bothrops leucurus venom, and examined their effects against Dengue virus (DENV). The Bl-PLA2s, named BlK-PLA2 and BlD-PLA2, are composed
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We report the detailed molecular characterization of two PLA2s, Lys49 and Asp49 isolated from Bothrops leucurus venom, and examined their effects against Dengue virus (DENV). The Bl-PLA2s, named BlK-PLA2 and BlD-PLA2, are composed of 121 and 122 amino acids determined by automated sequencing of the native proteins and peptides produced by digestion with trypsin. They contain fourteen cysteines with pIs of 9.05 and 8.18 for BlK- and BlD-PLA2s, and show a high degree of sequence similarity to homologous snake venom PLA2s, but may display different biological effects. Molecular masses of 13,689.220 (Lys49) and 13,978.386 (Asp49) were determined by mass spectrometry. DENV causes a prevalent arboviral disease in humans, and no clinically approved antiviral therapy is currently available to treat DENV infections. The maximum non-toxic concentration of the proteins to LLC-MK2 cells determined by MTT assay was 40 µg/mL for Bl-PLA2s (pool) and 20 µg/mL for each isoform. Antiviral effects of Bl-PLA2s were assessed by quantitative Real-Time PCR. Bl-PLA2s were able to reduce DENV-1, DENV-2, and DENV-3 serotypes in LLC-MK2 cells infection. Our data provide further insight into the structural properties and their antiviral activity against DENV, opening up possibilities for biotechnological applications of these Bl-PLA2s as tools of research. Full article
Open AccessReview Protease Inhibitors from Marine Venomous Animals and Their Counterparts in Terrestrial Venomous Animals
Mar. Drugs 2013, 11(6), 2069-2112; doi:10.3390/md11062069
Received: 19 April 2013 / Revised: 28 May 2013 / Accepted: 30 May 2013 / Published: 14 June 2013
Cited by 22 | Viewed by 2337 | PDF Full-text (1798 KB) | HTML Full-text | XML Full-text
Abstract
The Kunitz-type protease inhibitors are the best-characterized family of serine protease inhibitors, probably due to their abundance in several organisms. These inhibitors consist of a chain of ~60 amino acid residues stabilized by three disulfide bridges, and was first observed in the bovine
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The Kunitz-type protease inhibitors are the best-characterized family of serine protease inhibitors, probably due to their abundance in several organisms. These inhibitors consist of a chain of ~60 amino acid residues stabilized by three disulfide bridges, and was first observed in the bovine pancreatic trypsin inhibitor (BPTI)-like protease inhibitors, which strongly inhibit trypsin and chymotrypsin. In this review we present the protease inhibitors (PIs) described to date from marine venomous animals, such as from sea anemone extracts and Conus venom, as well as their counterparts in terrestrial venomous animals, such as snakes, scorpions, spiders, Anurans, and Hymenopterans. More emphasis was given to the Kunitz-type inhibitors, once they are found in all these organisms. Their biological sources, specificity against different proteases, and other molecular blanks (being also K+ channel blockers) are presented, followed by their molecular diversity. Whereas sea anemone, snakes and other venomous animals present mainly Kunitz-type inhibitors, PIs from Anurans present the major variety in structure length and number of Cys residues, with at least six distinguishable classes. A representative alignment of PIs from these venomous animals shows that, despite eventual differences in Cys assignment, the key-residues for the protease inhibitory activity in all of them occupy similar positions in primary sequence. The key-residues for the K+ channel blocking activity was also compared. Full article
(This article belongs to the Special Issue Marine Peptides and Their Mimetics)
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Open AccessArticle Venomous Secretions from Marine Snails of the Terebridae Family Target Acetylcholine Receptors
Toxins 2013, 5(5), 1043-1050; doi:10.3390/toxins5051043
Received: 5 December 2012 / Revised: 13 May 2013 / Accepted: 13 May 2013 / Published: 21 May 2013
Cited by 6 | Viewed by 2079 | PDF Full-text (625 KB) | HTML Full-text | XML Full-text
Abstract
Venoms from cone snails (Conidae) have been extensively studied during the last decades, but those from other members of the suborder Toxoglossa, such as of Terebridae and Turridae superfamilies attracted less interest so far. Here, we report the effects of venom and gland
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Venoms from cone snails (Conidae) have been extensively studied during the last decades, but those from other members of the suborder Toxoglossa, such as of Terebridae and Turridae superfamilies attracted less interest so far. Here, we report the effects of venom and gland extracts from three species of the superfamily Terebridae. By 2-electrode voltage-clamp technique the gland extracts were tested on Xenopus oocytes expressing nicotinic acetylcholine receptors (nAChRs) of rat neuronal (α3β2, α3β4, α4β2, α4β4, α7) and muscle subtypes (α1β1γδ), and expressing potassium (Kv1.2 and Kv1.3) and sodium channels (Nav1.2, 1.3, 1.4, 1.6). The extracts were shown to exhibit remarkably high inhibitory activities on almost all nAChRs tested, in particular on the α7 subtype suggesting the presence of peptides of the A-superfamily from the venom of Conus species. In contrast, no effects on the potassium and sodium channels tested were observed. The venoms of terebrid snails may offer an additional source of novel biologically active peptides. Full article
(This article belongs to the Special Issue Toxins from Aquatic Organisms)
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Open AccessReview The Snake Venom Rhodocytin from Calloselasma rhodostoma— A Clinically Important Toxin and a Useful Experimental Tool for Studies of C-Type Lectin-like Receptor 2 (CLEC-2)
Toxins 2013, 5(4), 665-674; doi:10.3390/toxins5040665
Received: 11 March 2013 / Revised: 1 April 2013 / Accepted: 7 April 2013 / Published: 17 April 2013
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Abstract
The snake venom, rhodocytin, from the Malayan viper, Calloselasma rhodostoma, and the endogenous podoplanin are identified as ligands for the C-type lectin-like receptor 2 (CLEC-2). The snakebites caused by Calloselasma rhodostoma cause a local reaction with swelling, bleeding and eventually necrosis, together
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The snake venom, rhodocytin, from the Malayan viper, Calloselasma rhodostoma, and the endogenous podoplanin are identified as ligands for the C-type lectin-like receptor 2 (CLEC-2). The snakebites caused by Calloselasma rhodostoma cause a local reaction with swelling, bleeding and eventually necrosis, together with a systemic effect on blood coagulation with distant bleedings that can occur in many different organs. This clinical picture suggests that toxins in the venom have effects on endothelial cells and vessel permeability, extravasation and, possibly, activation of immunocompetent cells, as well as effects on platelets and the coagulation cascade. Based on the available biological studies, it seems likely that ligation of CLEC-2 contributes to local extravasation, inflammation and, possibly, local necrosis, due to microthrombi and ischemia, whereas other toxins may be more important for the distant hemorrhagic complications. However, the venom contains several toxins and both local, as well as distant, symptoms are probably complex reactions that cannot be explained by the effects of rhodocytin and CLEC-2 alone. The in vivo reactions to rhodocytin are thus examples of toxin-induced crosstalk between coagulation (platelets), endothelium and inflammation (immunocompetent cells). Very few studies have addressed this crosstalk as a part of the pathogenesis behind local and systemic reactions to Calloselasma rhodostoma bites. The author suggests that detailed biological studies based on an up-to-date methodology of local and systemic reactions to Calloselasma rhodostoma bites should be used as a hypothesis-generating basis for future functional studies of the CLEC-2 receptor. It will not be possible to study the effects of purified toxins in humans, but the development of animal models (e.g., cutaneous injections of rhodocytin to mimic snakebites) would supplement studies in humans. Full article
(This article belongs to the collection Toxicity and Therapeutic Interventions in the Immune System)
Open AccessArticle Biochemical and Electrophysiological Characterization of Two Sea Anemone Type 1 Potassium Toxins from a Geographically Distant Population of Bunodosoma caissarum
Mar. Drugs 2013, 11(3), 655-679; doi:10.3390/md11030655
Received: 17 December 2012 / Revised: 23 January 2013 / Accepted: 15 February 2013 / Published: 6 March 2013
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Abstract
Sea anemone (Cnidaria, Anthozoa) venom is an important source of bioactive compounds used as tools to study the pharmacology and structure-function of voltage-gated K+ channels (KV). These neurotoxins can be divided into four different types, according to their structure and
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Sea anemone (Cnidaria, Anthozoa) venom is an important source of bioactive compounds used as tools to study the pharmacology and structure-function of voltage-gated K+ channels (KV). These neurotoxins can be divided into four different types, according to their structure and mode of action. In this work, for the first time, two toxins were purified from the venom of Bunodosoma caissarum population from Saint Peter and Saint Paul Archipelago, Brazil. Sequence alignment and phylogenetic analysis reveals that BcsTx1 and BcsTx2 are the newest members of the sea anemone type 1 potassium channel toxins. Their functional characterization was performed by means of a wide electrophysiological screening on 12 different subtypes of KV channels (KV1.1–KV1.6; KV2.1; KV3.1; KV4.2; KV4.3; hERG and Shaker IR). BcsTx1 shows a high affinity for rKv1.2 over rKv1.6, hKv1.3, Shaker IR and rKv1.1, while Bcstx2 potently blocked rKv1.6 over hKv1.3, rKv1.1, Shaker IR and rKv1.2. Furthermore, we also report for the first time a venom composition and biological activity comparison between two geographically distant populations of sea anemones. Full article
(This article belongs to the Special Issue Marine Neurotoxins)
Open AccessReview Glycosylation of Conotoxins
Mar. Drugs 2013, 11(3), 623-642; doi:10.3390/md11030623
Received: 14 December 2012 / Revised: 25 January 2013 / Accepted: 6 February 2013 / Published: 1 March 2013
Cited by 11 | Viewed by 2096 | PDF Full-text (1028 KB) | HTML Full-text | XML Full-text
Abstract
Conotoxins are small peptides present in the venom of cone snails. The snail uses this venom to paralyze and capture prey. The constituent conopeptides display a high level of chemical diversity and are of particular interest for scientists as tools employed in neurological
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Conotoxins are small peptides present in the venom of cone snails. The snail uses this venom to paralyze and capture prey. The constituent conopeptides display a high level of chemical diversity and are of particular interest for scientists as tools employed in neurological studies and for drug development, because they target with exquisite specificity membrane receptors, transporters, and various ion channels in the nervous system. However, these peptides are known to contain a high frequency and variability of post-translational modifications—including sometimes O-glycosylation—which are of importance for biological activity. The potential application of specific conotoxins as neuropharmalogical agents and chemical probes requires a full characterization of the relevant peptides, including the structure of the carbohydrate part. In this review, the currently existing knowledge of O-glycosylation of conotoxins is described. Full article
(This article belongs to the Special Issue Marine Glycoconjugates)
Open AccessCommunication ESI-MS/MS Identification of a Bradykinin-Potentiating Peptide from Amazon Bothrops atrox Snake Venom Using a Hybrid Qq-oaTOF Mass Spectrometer
Toxins 2013, 5(2), 327-335; doi:10.3390/toxins5020327
Received: 3 September 2012 / Revised: 13 December 2012 / Accepted: 16 December 2012 / Published: 18 February 2013
Cited by 5 | Viewed by 2554 | PDF Full-text (315 KB) | HTML Full-text | XML Full-text
Abstract
A bradykinin-potentiating peptide (BPP) from Amazon Bothrops atrox venom with m/z 1384.7386 was identified and characterized by collision induced dissociation (CID) using an ESI-MS/MS spectra obtained in positive ion mode on a hybrid Qq-oaTOF mass spectrometer, Xevo G2 QTof MS (Waters,
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A bradykinin-potentiating peptide (BPP) from Amazon Bothrops atrox venom with m/z 1384.7386 was identified and characterized by collision induced dissociation (CID) using an ESI-MS/MS spectra obtained in positive ion mode on a hybrid Qq-oaTOF mass spectrometer, Xevo G2 QTof MS (Waters, Manchester, UK). De novo peptide sequence analysis of the CID fragmentation spectra showed the amino acid sequence ZKWPRPGPEIPP, with a pyroglutamic acid and theoretical monoisotopic m/z 1384.7378, which is similar to experimental data, showing a mass accuracy of 0.6 ppm. The peptide is homologous to other BPP from Bothrops moojeni and was named as BPP-BAX12. Full article
Open AccessReview Venom Peptides as a Rich Source of Cav2.2 Channel Blockers
Toxins 2013, 5(2), 286-314; doi:10.3390/toxins5020286
Received: 2 November 2012 / Revised: 7 January 2013 / Accepted: 25 January 2013 / Published: 4 February 2013
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Abstract
Cav2.2 is a calcium channel subtype localized at nerve terminals, including nociceptive fibers, where it initiates neurotransmitter release. Cav2.2 is an important contributor to synaptic transmission in ascending pain pathways, and is up-regulated in the spinal cord in chronic
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Cav2.2 is a calcium channel subtype localized at nerve terminals, including nociceptive fibers, where it initiates neurotransmitter release. Cav2.2 is an important contributor to synaptic transmission in ascending pain pathways, and is up-regulated in the spinal cord in chronic pain states along with the auxiliary α2δ1 subunit. It is therefore not surprising that toxins that inhibit Cav2.2 are analgesic. Venomous animals, such as cone snails, spiders, snakes, assassin bugs, centipedes and scorpions are rich sources of remarkably potent and selective Cav2.2 inhibitors. However, side effects in humans currently limit their clinical use. Here we review Cav2.2 inhibitors from venoms and their potential as drug leads. Full article
(This article belongs to the Special Issue Animal Toxins Targeting Ion Channels Involved in Pain)
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Open AccessReview Cell-Penetrating Recombinant Peptides for Potential Use in Agricultural Pest Control Applications
Pharmaceuticals 2012, 5(10), 1054-1063; doi:10.3390/ph5101054
Received: 27 August 2012 / Revised: 21 September 2012 / Accepted: 21 September 2012 / Published: 28 September 2012
Cited by 5 | Viewed by 2039 | PDF Full-text (214 KB) | HTML Full-text | XML Full-text
Abstract
Several important areas of interest intersect in a class of peptides characterized by their highly cationic and partly hydrophobic structure. These molecules have been called cell-penetrating peptides (CPPs) because they possess the ability to translocate across cell membranes. This ability makes these peptides
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Several important areas of interest intersect in a class of peptides characterized by their highly cationic and partly hydrophobic structure. These molecules have been called cell-penetrating peptides (CPPs) because they possess the ability to translocate across cell membranes. This ability makes these peptides attractive candidates for delivery of therapeutic compounds, especially to the interior of cells. Compounds with characteristics similar to CPPs and that, in addition, have antimicrobial properties are being investigated as antibiotics with a reduced risk of causing resistance. These CPP-like membrane-acting antimicrobial peptides (MAMPs) are α-helical amphipathic peptides that interact with and perturb cell membranes to produce their antimicrobial effects. One source of MAMPs is spider venom. Because these compounds are toxic to insects, they also show promise for development as biological agents for control of insecticide-resistant agricultural pests. Spider venom is a potential source of novel insect-specific peptide toxins. One example is the small amphipathic α-helical peptide lycotoxin-1 (Lyt-1 or LCTX) from the wolf spider (Lycosa carolinensis). One side of the α-helix has mostly hydrophilic and the other mainly hydrophobic amino acid residues. The positive charge of the hydrophilic side interacts with negatively charged prokaryotic membranes and the hydrophobic side associates with the membrane lipid bilayer to permeabilize it. Because the surface of the exoskeleton, or cuticle, of an insect is highly hydrophobic, to repel water and dirt, it would be expected that amphipathic compounds could permeabilize it. Mutagenized lycotoxin 1 peptides were produced and expressed in yeast cultures that were fed to fall armyworm (Spodoptera frugiperda) larvae to identify the most lethal mutants. Transgenic expression of spider venom toxins such as lycotoxin-1 in plants could provide durable insect resistance. Full article
(This article belongs to the Special Issue Cell-penetrating Peptides 2012)
Open AccessCommunication Inhibition of Melanization by a Parasitoid Serine Protease Homolog Venom Protein Requires Both the Clip and the Non-Catalytic Protease-Like Domains
Insects 2011, 2(4), 509-514; doi:10.3390/insects2040509
Received: 18 October 2011 / Revised: 10 November 2011 / Accepted: 15 November 2011 / Published: 25 November 2011
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Abstract
Endoparasitoid wasps inject a variety of components into their host hemocoel at oviposition to facilitate successful development of their progeny. Among these are venom proteins which have been shown to play crucial roles in host regulation. A serine protease homolog (SPH)-like venom protein
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Endoparasitoid wasps inject a variety of components into their host hemocoel at oviposition to facilitate successful development of their progeny. Among these are venom proteins which have been shown to play crucial roles in host regulation. A serine protease homolog (SPH)-like venom protein from Cotesia rubecula was previously shown to inhibit melanization in the host hemolymph by blocking activation of prophenoloxidase to phenoloxidase, a key enzyme in melanin formation. Similar to other SPHs, Vn50 consists of a clip and a protease-like (SPL) domain. Protein modeling demonstrated that Vn50 has a very similar structure to known SPHs and functional analysis of Vn50 domains expressed in insect cells indicated that neither of the domains on its own has an inhibitory effect on melanization. Full article
(This article belongs to the Special Issue Symbiosis: A Source of Evolutionary Innovation in Insects)
Open AccessArticle Isolation and Biochemical Characterization of Rubelase, a Non-Hemorrhagic Elastase from Crotalus ruber ruber (Red Rattlesnake) Venom
Toxins 2011, 3(7), 900-910; doi:10.3390/toxins3070900
Received: 9 May 2011 / Revised: 28 June 2011 / Accepted: 12 July 2011 / Published: 19 July 2011
Cited by 5 | Viewed by 2143 | PDF Full-text (420 KB) | HTML Full-text | XML Full-text
Abstract
A novel non-hemorrhagic basic metalloprotease, rubelase, was isolated from the venom of Crotalus ruber ruber. Rubelase hydrolyzes succinyl-L-alanyl-L-alanyl-L-alanyl p-nitroanilide (STANA), a specific substrate for elastase, and the hydrolytic activity was inhibited by chelating agents. It also hydrolyzes collagen and fibrinogen. However,
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A novel non-hemorrhagic basic metalloprotease, rubelase, was isolated from the venom of Crotalus ruber ruber. Rubelase hydrolyzes succinyl-L-alanyl-L-alanyl-L-alanyl p-nitroanilide (STANA), a specific substrate for elastase, and the hydrolytic activity was inhibited by chelating agents. It also hydrolyzes collagen and fibrinogen. However, hemorrhagic activity was not observed. By ESI/Q-TOF and MALDI/TOF mass spectrometry combined with Edman sequencing procedure, the molecular mass of rubelase was determined to be 23,266 Da. Although its primary structure was similar to rubelysin (HT-2), a hemorrhagic metalloprotease isolated from the same snake venom, the circumstances surrounding putative zinc binding domain HEXXHXXGXXH were found to be different when the three-dimensional computer models of both metalloproteases were compared. The cytotoxic effects of rubelase and rubelysin on cultured endothelial and smooth muscle cells were also different, indicating that the substitution of several amino acid residues causes the changes of active-site conformation and cell preference. Full article
Open AccessArticle Effects of Spider Venom Toxin PWTX-I (6-Hydroxytrypargine) on the Central Nervous System of Rats
Toxins 2011, 3(2), 142-162; doi:10.3390/toxins3020142
Received: 18 January 2011 / Revised: 1 February 2011 / Accepted: 12 February 2011 / Published: 22 February 2011
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Abstract
The 6-hydroxytrypargine (6-HT) is an alkaloidal toxin of the group of tetrahydro-b-carbolines (THbC) isolated from the venom of the colonial spider Parawixia bistriata. These alkaloids are reversible inhibitors of the monoamine-oxidase enzyme (MAO), with hallucinogenic, tremorigenic and anxiolytic properties. The toxin 6-HT
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The 6-hydroxytrypargine (6-HT) is an alkaloidal toxin of the group of tetrahydro-b-carbolines (THbC) isolated from the venom of the colonial spider Parawixia bistriata. These alkaloids are reversible inhibitors of the monoamine-oxidase enzyme (MAO), with hallucinogenic, tremorigenic and anxiolytic properties. The toxin 6-HT was the first THbC chemically reported in the venom of spiders; however, it was not functionally well characterized up to now. The action of 6-HT was investigated by intracerebroventricular (i.c.v.) and intravenous (i.v.) applications of the toxin in adult male Wistar rats, followed by the monitoring of the expression of fos-protein, combined with the use of double labeling immunehistochemistry protocols for the detection of some nervous receptors and enzymes related to the metabolism of neurotransmitters in the central nervous system (CNS). We also investigated the epileptiform activity in presence of this toxin. The assays were carried out in normal hippocampal neurons and also in a model of chronic epilepsy obtained by the use of neurons incubated in free-magnesium artificial cerebro-spinal fluid (ACSF). Trypargine, a well known THbC toxin, was used as standard compound for comparative purposes. Fos-immunoreactive cells (fos-ir) were observed in hypothalamic and thalamic areas, while the double-labeling identified nervous receptors of the sub-types rGlu2/3 and NMR1, and orexinergic neurons. The 6-HT was administrated by perfusion and ejection in “brain slices” of hippocampus, inducing epileptic activity after its administration; the toxin was not able to block the epileptogenic crisis observed in the chronic model of the epilepsy, suggesting that 6-HT did not block the overactive GluRs responsible for this epileptic activity. Full article
(This article belongs to the Special Issue Spider Venoms)
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Open AccessArticle Anti-hemorrhagic Activity of Four Brazilian Vegetable Species Against Bothrops jararaca Venom
Molecules 2009, 14(3), 1072-1080; doi:10.3390/molecules14031072
Received: 26 November 2008 / Revised: 30 December 2008 / Accepted: 21 January 2009 / Published: 9 March 2009
Cited by 20 | Viewed by 10012 | PDF Full-text (117 KB) | HTML Full-text | XML Full-text
Abstract
Around 20,000 snakebites are reported annually in Brazil and 90% of them are inflicted by species of the genus Bothrops. Intravenous administration of antibothropic antivenom neutralizes the systemic actions, but it is of little effect on the reversal of local symptoms and
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Around 20,000 snakebites are reported annually in Brazil and 90% of them are inflicted by species of the genus Bothrops. Intravenous administration of antibothropic antivenom neutralizes the systemic actions, but it is of little effect on the reversal of local symptoms and often induces adverse reactions, a context that drives the search for complementary treatments for snakebite accidents. Vegetable extracts with a range of antiophidian activities constitute an excellent alternative. In this study, we investigated the anti-hemorrhagic effects of Mouriri pusa Gardn. (Melastomataceae), Byrsonima crassa Niedenzu (Malpighiaceae), Davilla elliptica St. Hill. (Dilleniaceae) and Strychnos pseudoquina St. Hil. (Loganiaceae) against Bothrops jararaca venom. The methanolic extracts from M. pusa (leaves), B. crassa (leaves) and D. elliptica (leaves) showed total neutralization capacity against local hemorrhages. The amenthoflavone and quercetin fractions from B. crassa and the flavonoids fractions (quercetin and myricetin) from M. pusa and D. elliptica also showed total neutralization capacity. We conclude that flavonoids derived from myricetin, quercetin and amenthoflavone play an important role in the anti-hemorrhagic potential of these Brazilian vegetables species against B. jararaca venom. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)

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