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• Purified enzyme isoforms had differential coagulotoxic activity. • This variation was linked to differential ability to activate Factor X vs prothrombin. • This variation was linked to differential antiveom efficacy. Bothrops (lance-head pit vipers) venoms are rich in weaponised metalloprotease enzymes (SVMP). These toxic enzymes are structurally diverse and functionally versatile. Potent coagulotoxicity is particularly important for prey capture (via stroke-induction) and relevant to human clinical cases (due to consumption of clotting factors including the critical depletion of fibrinogen). In this study, three distinct isoforms of P-III class SVMPs (IC, IIB and IIC), isolated from Bothrops neuwiedi venom, were evaluated for their differential capacities to affect hemostasis of prey and human plasma. Furthermore, we tested the relative antivenom neutralisation of effects upon human plasma. The toxic enzymes displayed differential procoagulant potency between plasma types, and clinically relevant antivenom efficacy variations were observed. Of particular importance was the confirmation the antivenom performed better against prothrombin activating toxins than Factor X activating toxins, which is likely due to the greater prevalence of the former in the immunising venoms used for antivenom production. This is clinically relevant as the enzymes displayed differential potency in this regard, with one (IC) in particular being extremely potent in activating Factor X and thus was correspondingly poorly neutralised. This study broadens the current understanding about the adaptive role of the SVMPs, as well as highlights how the functional diversity of SVMP isoforms can influence clinical outcomes. Key Contribution: Our findings shed light upon the hemorrhagic and coagulotoxic effects of three SVMPs of the P-III class, as well as the coagulotoxic effects of SVMPs on human, avian and amphibian plasmas. Antivenom neutralised prothrombin-activating isoforms better than Factor X activating isoforms. [ABSTRACT FROM AUTHOR]

Type II diabetes mellitus (T2DM) is a chronic non‐communicable disease due to abnormal insulin actions causing uncontrolled hyperglycaemia. The treatment for T2DM, for instance, metformin and incretin mimetic, mainly focuses on the restoration of insulin sensitivity and secretion. Exendin‐4 is a short incretin‐mimetic peptide consisting of 39 amino acids. It is discovered in the venom of Heloderma suspectum as a full agonist for the glucagon‐like peptide 1 (GLP‐1) receptor and produces insulinotropic effects. It is more resistant to enzymatic degradation by dipeptidyl‐peptidase‐4 and has a longer half‐life than the endogenous GLP‐1; thus, it is further developed as an incretin hormone analogue used to treat T2DM. The helical region of the peptide first interacts with the extracellular N‐terminal domain (NTD) of GLP‐1 receptor while the C‐terminal extension containing the tryptophan cage further enhances its binding affinity. After binding to the NTD of the receptor, it may cause the receptor to switch from its auto‐inhibited state of the receptor to its auto‐activated state. Exendin‐4 enhances the physiological functions of β‐cells and the up‐regulation of GLP‐1 receptors, thus reducing the plasma glucose levels. Moreover, exendin‐4 has also been found to ameliorate neuropathy, nephropathy and ventricular remodelling. The therapeutic effects of exendin‐4 have also been extrapolated into several clinical trials. Although exendin‐4 has a reasonable subcutaneous bioavailability, its half‐life is rather short. Therefore, several modifications have been undertaken to improve its pharmacokinetics and insulinotropic potency. This review focuses on the pharmacology of exendin‐4 and the structure‐function relationships of exendin‐4 with GLP‐1 receptor. The review also highlights some challenges and future directions in the improvement of exendin‐4 as an anti‐diabetic drug. [ABSTRACT FROM AUTHOR]

Abstract Envenomation by scorpions of the genus Tityus is an important public health problem in Argentina, involving near 8000 stings and 2 deaths each year. Treatment for envenomation is the use of specific antivenom and intensive hospital care. Antivenom is produced by the Ministry of Health and freely distributed throughout the country. For antivenom production it is necessary to collect scorpion venom, which is a difficult task because although scorpions can be found in Argentina, they are less abundant than in warmer latitudes. For this reason venom collection constitutes a bottleneck for antivenom production. Although in Argentina several species of Tityus can be found, most of the accidents are caused by Tityus trivittatus, and the venom of this scorpion has historically been the venom used for antivenom production. We analyzed retrospectively 26 pools of telson homogenates (6964 telsons) and 37 pools of milked venom obtained by electrical stimulation (equivalent to 6841 milkings). Lethal potencies of samples from different provinces were very similar, although venom from scorpions of Buenos Aires city showed the lowest potency. The venom obtained by milking (median LD 50 12.3 μg), provided batches containing LD 50 s more potent when compared with the venom obtained from telson homogenates (p < 0.0001). Many batches of telson homogenates (30%) showed lower potencies than acceptable for antivenom production and control. In addition to the study of the venom yield, the records of immunization of horses, the potency of the batches and the protein content of each batch of anti-scorpion antivenom produced were analyzed, comparing those produced using milked venom with those using telson homogenates as immunogens. Batches produced using milked venom required a shorter period of immunization (p < 0.0001), rendered higher neutralizing titers (p 0.0350) and possessed lower protein content (p 0.0092). Results clearly showed that the milking of scorpions is a more efficient tool to obtain venom for antivenom production in comparison to the use of telson homogenates. Highlights • We analyzed 26 pools of telson homogenates (6964 telsons) and 37 of milked venom (6841 milkings). • The potency and the number of LD 50 s per milking were higher that those of telson homogenates. • Low toxic variability between regions was found. • 30% of the batches of homogenates did not posses quality enough to be used for antivenom production. • Milked venoms present advantages over telson homogenates for antivenom production. [ABSTRACT FROM AUTHOR]

This review presents the main contributions to our knowledge regarding the development of antivenoms for therapeutic use in victims of venomous animal bites. We cover the progress of serum therapy since tetanus and diphtheria antitoxins in Germany and France until the current scenario of antivenom production worldwide. During these more than 120 years of antivenom development, many researchers contributed to establish what are nowadays the antivenoms used for therapeutic purpose. The history of antivenoms development is fascinating! This review aims to recognize all those who contributed to the establishment of new sera, new methodologies and saving lives: much more than Calmette and Vital Brazil. [ABSTRACT FROM AUTHOR]

The growing world population is placing an increasing demand on food production. In addition, abuse and misuse of chemical insecticides has led to the evolution of resistance in insect pests as well as environmental damage. Together, these developments have created a demand for new insecticidal compounds to facilitate global food production. Arachnid venom peptides provide an environmentally-friendly alternative as potential bioinsecticides given their advantages of being fully biodegradable, highly potent, and phyletically selective. However, the use of arachnid venom peptides as bioinsecticides has been questioned due to their presumed lack of oral toxicity. Thus, the aim of this work was to develop screens for oral insecticidal activity. Based on the high susceptibility of dipterans to venom peptides, fruit flies ( Drosophila melanogaster ) and sheep blowflies ( Lucilia cuprina ) were selected for screening 56 arachnid venoms. 71.4% of these venoms caused 50% or higher mortality in Drosophila , whereas 30.4% were lethal to blowflies at oral doses of 1 or 30 μg/fly, respectively. We used these assays to compare the oral and injection activity of four well-known spider venom peptides (Hv1a, Hv1c, Dc1a and Ta1a). Hv1c and Ta1a only showed weak or no oral activity in both species, while Hv1a and Dc1a showed higher oral activity in blowflies than Drosophila . Overall, we have established screens for oral toxicity in two dipteran insects. Our results indicate that oral insecticidal activity is more widespread in arachnid venoms than expected, and that some arachnid venoms and venom peptides exhibit phyletic differences in oral toxicity. [ABSTRACT FROM AUTHOR]

The consequences of scorpion stings on the affected victims, including humans, have been known since ancient times. The effects of the venom, first on neurotransmission and thereafter on many physiological processes at the organism, tissue, cellular or molecular levels, have been the subject of intense research. It is, therefore, not surprising that a large number of toxins acting on a variety of ion channels have been isolated and described to date. Many of these toxins show high specificities and affinities towards their natural targets. Along with their own biochemical and biophysical characterization, scorpion toxins have been used as invaluable tools for studies regarding the structure and function of ion channels. They have also become important leads in drug development aiming at diagnosing, targeting or direct treatment of channelopathies caused by the improper function of those channels they recognize, as well as other anomalous physiological conditions, including autoimmune diseases and cancer. The main families of scorpion toxins are reviewed here, among which are those specific for Na + , K + and ryanodine-sensitive Ca 2+ channels. The focus is placed on the historical events that led to their discovery and their use in the identification and characterization of the structure and function of ion channels. Their potential use in medicine is also presented. [ABSTRACT FROM AUTHOR]

In the 1890s, hyperimmune sera proved effective in animals against challenge by the snake venom against which they had been raised. They were first used, apparently successfully, in a human patient in about 1895. Since then, antivenoms have become accepted as the only reliable specific treatment for snake-bite envenoming. Despite decades of accumulated clinical experience and a number of published randomized comparative and observational studies, the clinical effectiveness and safety of some antivenoms remain open to question, due to a lack of robust randomized controlled trial data. Antivenoms in some poorly regulated markets may have high rates of potentially fatal adverse effects and their use must be balanced by demonstrable effectiveness. Even those manufactured to strict regulatory requirements may pose a rare risk of severe adverse reactions. Most antivenoms currently marketed around the world were registered without first being studied clinically. There is increasing pressure to subject antivenoms, even those that are long-established, to the same protocols of rigorous pre-clinical and clinical assessment that are standard regulatory requirements for other drugs. Conventional clinical testing progresses through Phases I, II, III to IV. Most authorities consider antivenoms too dangerous to be used in Phase I studies in healthy volunteers. An alternative method for preliminary estimation of safety, dose-finding and effectiveness, is proposed - the “3 + 3” dose escalation or de-escalation design, in volunteer patients, as used in oncology to test cytotoxic drugs. Antivenoms are so widely used and well trusted, that there are few ethical justifications for placebo controls. However, placebo might be ethically justified if there were no proven effective treatment and or if withholding or delaying treatment posed acceptably negligible risks to the participants. Antivenom trials are most urgently needed in low-to middle-income countries where there are many practical, logistical and funding challenges. Basic requirements for clinical trials include identification of the biting species of snake in every case; the use of objective, clinically-relevant endpoints, such as restoration of blood coagulability; definition of inclusion, exclusion and withdrawal criteria; assurance of antivenom safety; ethical considerations; inclusion of one or more control (comparator) groups; and analysis based on intention to treat. The highest quality evidence comes from Phase II and larger Phase III studies that have been designed as statistically powerful, randomized, controlled trials (RCTs), ideally with blinding of patients and investigators to avoid bias. Because of the challenges to carrying out clinical trials of antivenoms, Phase IV trials (post-marketing surveillance) are potentially more important and useful than for most other drugs. [ABSTRACT FROM AUTHOR]

The scourge of snakebite has been well documented but largely ignored by the global health community for several decades, especially the role that economics has played in causing and exacerbating this crisis. Every year millions of people in low and middle-income countries face death, disability and disadvantage from snakebite envenoming (SBE) without access to appropriate treatment. Health-economic factors pervade every aspect of this neglected problem. A multitude of financial and commercial factors helped to cause, and now perpetuate, shortages of high quality, affordable and region-appropriate antivenom in areas where they are most needed. Alongside the death, physical disability and psychological anguish from SBE is a debilitating financial toll, which includes both direct costs of treatment and indirect costs from lost income. SBE is a problem that disproportionately affects poor, rural and agrarian communities, with most victims being young and industrious subsistence workers. The burden of envenoming is often felt by families and communities that can least afford it, and negatively impacts local and national productivity. The lack of long-term investment in health systems to properly manage SBE has led to insufficient funding for antivenom development, procurement, quality control and distribution, despite highly favourable cost effectiveness of some antivenoms. This has contributed to market failures that have seen antivenom output fall and become inaccessible to most victims. Solutions to these problems exist and are achievable, however the challenge for advocates is to appreciate the importance of health-economics and ensure that strategies to redress the economic causes and consequences of SBE are themselves cost-effective and financially sustainable. [ABSTRACT FROM AUTHOR]

Sea anemone venom is rich in bioactive compounds, including peptides containing multiple disulfide bridges. In a transcriptomic study on Oulactis sp., we identified the putative 36-residue peptide, OspTx2b, which is an isoform of the K V channel blocker OspTx2a (Sunanda P et al. [2018] Identification, chemical synthesis, structure and function of a new K V 1 channel blocking peptide from Oulactis sp. Peptide Science , in press). As OspTx2b contains a ShK/BgK-like cysteine framework, with high amino acid sequence similarity to BgK, we were interested to investigate its structure and function. The solution structure of OspTx2b was determined using nuclear magnetic resonance spectroscopy. OspTx2b does indeed possess a BgK-like scaffold, with the same disulfide bond connectivities. The orientation of the Lys-Tyr dyad in OspTx2b is more similar to that in ShK than in BgK. However, it failed to show against a range of voltage-gated potassium channels in Xenopus oocytes and human T lymphocytes. OspTx2b also showed no growth inhibitory activity against several strains of bacteria and fungi. Having a BgK-like fold with the Lys-Tyr dyad but no BgK-like activity highlights the importance of key amino acid residues in BgK that are missing in OspTx2b. The lack of activity against the K V channels assessed in this study emphasises that the ShK/BgK scaffold is capable of supporting functional activity beyond potassium channel blockade. [ABSTRACT FROM AUTHOR]

With the threat of a post-antibiotic era looming, the search for new and effective antibiotics from novel sources is imperative. Not only has crude snake venom been shown to be effective, but specific components within the venoms, such as Phospholipase A 2 s and l -amino acid oxidases have been isolated and demonstrated to be effective as well. Despite numerous studies being completed on snake venoms, there is a heavy bias towards utilizing the venoms from the highly toxic Elapidae and Viperidae species. Very few studies have been conducted on the less toxic, but taxonomically more diverse, Colubridae. Furthermore, an extensive review of the literature examining the efficacy and potential specificity of these venoms has not been completed. Therefore, the aims of this study were to elucidate any similarities in snake venoms as well as investigate the efficacy of snake venom antimicrobial properties towards morphologically and metabolically diverse microbial classes and the prevalence of snake species with antimicrobial properties within each snake family. The results indicate that snake venoms and their isolated components are powerful antimicrobial agents but vary in efficacy towards different microbial classes. Furthermore, due to similarities in venom composition, and limited preliminary studies, the less toxic Colubridae family may be a fruitful area of research to find novel antimicrobial agents that are less harmful to humans. [ABSTRACT FROM AUTHOR]

Proteins that account for the hemolytic activity found in scorpaeniform fish venoms are responsible for the majority of the effects observed upon envenomation, for instance, neurotoxic, cardiotoxic and inflammatory effects. These multifunctional toxins, described as protein lethal factors and referred to as cytolysins, are known to be extremely labile molecules. In the present work, we endeavored to overcome this constraint by determining optimal storage conditions for Sp-CTx, the major bioactive component from the scorpionfish Scorpaena plumieri venom. This cardiotoxic hemolytic cytolysin is a large dimeric glycoprotein (subunits of ≈65 kDa) with pore-forming ability. We were able to establish storage conditions that allowed us to keep the toxin partially active for up to 60 days. Stability was achieved by storing Sp-CTx at −80 and −196 °C in the presence of glycerol 10% in a pH 7.4 solution. It was demonstrated that the hemolytic activity of Sp-CTx is calcium dependent, being abolished by EDTA and zinc ions. Furthermore, the toxin exhibited its maximal hemolytic activity at pH between 8 and 9, displaying typical N- and O- linked glycoconjugated residues (galactose (1–4) N-acetylglucosamine and sialic acid (2–3) galactose in N- and/or O-glycan complexes). The hemolytic activity of Sp-CTx was inhibited by phosphatidylglycerol and phosphatidylethanolamine, suggesting a direct electrostatic interaction lipid - toxin in the pore-formation mechanism of action of this toxin. In addition, we observed that the hemolytic activity was inhibited by increasing doses of cholesterol. Finally, we were able to show, for first time, that Sp-CTx is at least partially responsible for the pain and inflammation observed upon envenomation. However, while the edema induced by Sp-CTx was reduced by pre-treatment with aprotinin and HOE-140, pointing to the involvement of the kallikrein-kinin system in this response, these drugs had no significant effect in the toxin-induced nociception. Taken together, our results could suggest that, as has been already reported for other fish cytolysins, Sp-CTx acts mostly through lipid-dependent pore formation not only in erythrocytes but also in other cell types, which could account for the pain observed upon envenomation. We believe that the present work paves the way towards the complete characterization of fish cytolysins. [ABSTRACT FROM AUTHOR]

Background: Honey bee venom is an important toxin which has various useful properties. Bee venom possesses various peptides including melittin, apamin, adolapamin and mast cell degranulating peptide. It appears to stimulate cortisone secretion, enhances antibody production, and affects cytokine production. Aim: The aim of the work is to study changes in levels of complement system proteins, C3 and C4, together with C-reactive proteins and rheumatoid factors (CRP and RF) in response to bee venom in subjects exposed naturally to sting with honey bee workers. Subjects and Methods: Subjects (12) were randomly selected from patients visiting El-Mostafa bee house, Elmarg, cairo, Egypt; to get natural bee venom therapy for various diseases. Blood samples (24) were collected from these volunteers, before and after honey bee sting, at the laboratory of Egypt Air Hospital, Cairo, Egypt following the standard protocol. Serum levels of C3 and C4 were measured by radial immunodiffusion technique. CRP was quantitatively measured by in vitro diagnostic test using auto analyzer (Dimension® EXEL) clinical chemistry system. Serum RF was measured by Rapid latex agglutination test for qualitative screening. Result: After exposure of patients to bee sting: all abnormal levels of C3 returned to normal values while abnormal C4 levels did not change; Half of cases that were showing abnormal high CRP levels have dropped to normal levels and All RF positive cases have become negative. Conclusion: The complement system has been activated, in patients, by both classical and alternative pathways before treatment with bee venom where it became only classically activated after treatment. Improved values of both CRP and RF indicate reduction in the inflammatory immune response after exposure of patients to honey bee venom. [ABSTRACT FROM AUTHOR]

There are 3 species of hump-nosed pit vipers in Sri Lanka: Hypnale hypnale, Hypnale zara, and Hypnale nepa. The latter 2 are endemic to the country. Microangiopathic hemolytic anemia (MAHA) is a known complication of hump-nosed pit viper bites. It was previously documented as a complication of general viper bites and not species specific. We report a series of 3 patients who developed MAHA after being bitten by each species of hump-nosed pit viper. The first patient was bitten by H hypnale and developed a severe form of MAHA associated with acute kidney injury and thrombocytopenia falling into the category of thrombotic microangiopathy. The other 2 developed MAHA that resolved without any complications. [ABSTRACT FROM AUTHOR]

Different types of neuronal nicotinic acetylcholine receptors (nAChRs) are expected to occur in vivo, most structure-activity relationship studies have been carried out for just a few neuronal subtypes. The present review enlightens current aspects of venom modulators of nAChRs. Important electronic databases such as PubMed or Google scholar were explored for the collection of latest studies in the field. Clinical and basic research has shown that cholinergic receptors play a role in several disorders of the nervous system such as chronic pain, Alzheimer's disease and addiction to nicotine, alcohol and drugs. Unfortunately, the lack of selective modulators for each subtype of nAChR makes their pharmacological characterization difficult, which has slowed the development of therapeutic nAChR modulators with high selectivity and absence of off-target side-effects. Animal venoms have proven to be an excellent natural source of bioactive molecules with activity against ion channels. The present review concludes that the presence of small-molecule nAChR modulators in spider venoms support the use of venoms as a potential source of novel modulators. [ABSTRACT FROM AUTHOR]

Rattlesnake venoms may be classified according to the presence/absence and relative abundance of the neurotoxic phospholipases A2s (PLA2s), such as Mojave toxin, and snake venom metalloproteinases (SVMPs). In Mexico, studies to determine venom variation in Mojave Rattlesnakes (Crotalus scutulatus scutulatus) are limited and little is known about the biological and proteolytic activities in this species. Tissue (34) and venom (29) samples were obtained from C. s. scutulatus from different locations within their distribution in Mexico. Mojave toxin detection was carried out at the genomic (by PCR) and protein (by ELISA) levels for all tissue and venom samples. Biological activity was tested on representative venoms by measuring LD50 and hemorrhagic activity. To determine the approximate amount of SVMPs, 15 venoms were separated by RP-HPLC and variation in protein profile and proteolytic activity was evaluated by SDS-PAGE (n = 28) and Hide Powder Azure proteolytic analysis (n = 27). Three types of venom were identified in Mexico which is comparable to the intraspecific venom diversity observed in the Sonoran Desert of Arizona, USA: Venom Type A (~Type II), with Mojave toxin, highly toxic, lacking hemorrhagic activity, and with scarce proteolytic activity; Type B (~Type I), without Mojave toxin, less toxic than Type A, highly hemorrhagic and proteolytic; and Type A + B, containing Mojave toxin, as toxic as venom Type A, variable in hemorrhagic activity and with intermediate proteolytic activity. We also detected a positive correlation between SVMP abundance and hemorrhagic and proteolytic activities. Although more sampling is necessary, our results suggest that venoms containing Mojave toxin and venom lacking this toxin are distributed in the northwest and southeast portions of the distribution in Mexico, respectively, while an intergradation in the middle of both zones is present. [ABSTRACT FROM AUTHOR]

The Nose-horned Viper (Vipera ammodytes) is one of the most widespread and venomous snakes in Europe, which causes high frequent snakebite accidents. The first comprehensive venom characterization of the regional endemic Transcaucasian Nose-horned Viper (Vipera ammodytes transcaucasiana) and the Transdanubian Sand Viper (Vipera ammodytes montandoni) is reported employing a combination of intact mass profiling and bottom-up proteomics. The bottom-up analysis of both subspecies identified the major snake protein families of viper venoms. Furthermore, intact mass profiling revealed the presence of two tripeptidic metalloprotease inhibitors and their precursors. While previous reports applied multivariate analysis techniques to clarify the taxonomic status of the subspecies, an accurate classification of Vipera ammodytes transcaucasiana is still part of the ongoing research. The comparative analysis of the viper venoms on the proteome level reveals a close relationship between the Vipera ammodytes subspecies, which could be considered to clarify the classification of the Transcaucasian Nose-horned Viper. However, the slightly different ratio of some venom components could be indicating interspecific variations of the two studied subspecies or intraspecies alternations based on small sample size. Additionally, we performed a bioactivity screening with the crude venoms against several human cancerous and non-cancerous cell lines, which showed interesting results against a human breast adenocarcinoma epithelial cell line. Several fractions of Vipera a. transcaucasiana demonstrated a strong cytotoxic effect on triple negative MDA MB 231 breast cancer cells. [ABSTRACT FROM AUTHOR]

Venoms are produced by a wide variety of species including spiders, scorpions, reptiles, cnidarians, and fish for the purpose of harming or incapacitating predators or prey. While some venoms are of relatively simple composition, many contain hundreds to thousands of individual components with distinct pharmacological activity. Pain-inducing or "algesic" venom compounds have proven invaluable to our understanding of how physiological nociceptive neural networks operate. In this review, we present an overview of some of the diverse nociceptive pathways that can be modulated by specific venom components to evoke pain. [ABSTRACT FROM AUTHOR]

Assessing the neutralization capability of nonlethal but medically relevant toxins in venom has been a challenging task. Nowadays, neutralization efficacy is evaluated based simply on the survival rates of animals injected with antivenom together with a predefined dose of venom, which can determine potency against neurotoxicity but not validate the capability to neutralize cytotoxin-induced complications. In this study, a high correlation with in-vivo and in-vitro neutralization assays was established using the immunoreactive peptides identified from short-chain neurotoxin and cytotoxin A3. These peptides contain conserved residues associated with toxin activities and a competition assay indicated that these peptides could specifically block the antibody binding to toxin and affect the neutralization potency of antivenom. Moreover, the titers of peptide-specific antibody in antivenoms or mouse antisera were determined by enzyme-linked immunosorbent assay (ELISA) simultaneously, and the results indicated that Taiwanese bivalent antivenom (BAV) and Vietnamese snake antivenom-Naja (SAV-Naja) exhibited superior neutralization potency against the lethal effect of short-chain neurotoxin (sNTX) and cytotoxicity of cardiotoxin/cytotoxin (CTX), respectively. Thus, the reported peptide ELISA shows not only its potential for antivenom prequalification use, but also its capability of justifying the cross-neutralization potency of antivenoms against Naja atra venom toxicity. [ABSTRACT FROM AUTHOR]

Accidents involving venomous snakes are a public health problem worldwide, causing a large number of deaths per year. In Brazil, the majority of accidents are caused by the Bothrops and Crotalus genera, which are responsible for approximately 80% of severe envenoming cases. The cross-neutralization of snake venoms by antibodies is an important issue for development of more effective treatments. Our group has previously reported the construction of human monoclonal antibody fragments towards Bothrops jararacussu and Crotalus durissus terrificus ’ venoms. This study aimed to select human single-chain variable fragments (scFvs) that recognize both bothropic and crotalic crude venoms following venoms neutralizing capacity in vitro and in vivo . The cross-reactivity of Cro-Bothrumabs were demonstrated by ELISA and in vitro and in vivo experiments showed that a combination of scFvs neutralizes in vitro toxic activities ( e.g. indirect hemolysis and plasma-clotting) of crotalic and bothropic venoms as well as prolonged survival time of envenomed animals. Our results may contribute to the development of the first human polyvalent antivenom against Bothrops jararacussu and Crotalus durissus terrificus venoms, overcoming some undesirable effects caused by conventional serotherapy. [ABSTRACT FROM AUTHOR]

Background: Venom immunotherapy (VIT) is considered to be the gold standard treatment for patients with hymenoptera venom allergy. This treatment induces systemic reactions (SR) in a significant number of patients. Objective: To evaluate the outcome of VIT in patients with known risk factors for VIT-induced SR and to compare rush VIT (RVIT) and conventional VIT (CVIT). Methods: All of the patients who received VIT and had at least one of the following risk factors were included: current cardiovascular disease, uncontrolled asthma, high basal serum tryptase, current treatment with β-blockers or angiotensin-converting enzyme inhibitors, and age >70 or <5 years. Results: Sixty-four patients were included, and most of them (52; 81.5%) were allergic exclusively to bee venom. Thirty-five (54.7%) patients underwent RVIT and 29 CVIT. The incidence of patients who developed SR during the build-up phase was similar for RVIT and CVIT (25.7 and 27.5%, respectively; p = 1). However, the incidence of SR per injection was significantly higher in CVIT than in RVIT (5.6 and 2.75%, respectively; p = 0.01). Most reactions (79.1%) were mild, limited to the skin. Most of the patients (92.1%) reached the full maintenance dose of 100 μg. This dose was reached by a significantly larger number of patients receiving RVIT compared to CVIT (100 and 82.7%, respectively; p = 0.01). None of the patients experienced exacerbation of their concurrent chronic disease during VIT. Conclusion: VIT can be performed safely and efficiently in patients with risk factors for immunotherapy. In these patients RVIT appears to be safer and more efficient than CVIT. [ABSTRACT FROM AUTHOR]

Small membranous vesicles are small closed fragments of membrane. They are released from multivesicular bodies (exosomes) or shed from the surface membrane (microvesicles). They contains various bioactive molecules and their molecular composition varies depending on their cellular origin. Small membranous vesicles have been identified in snake venoms, but the origin of these small membranous vesicles in the venom is controversial. The aim of this study was to verify the origin of the small membranous vesicles in venom of Crotalus durissus terrificus by morphological analyses using electron microscopy. In addition, the protein composition of the vesicles was analyzed by using a proteome approach. The small membranous vesicles present in the venom were microvesicles, since they originated from microvilli on the apical membrane of secretory cells. They contained cytoplasmic proteins, and proteins from the plasma membrane, endoplasmic reticulum (ER), and Golgi membrane. The release of microvesicles may be a mechanism to control the size of the cell membrane of the secretory cells after intense exocytosis. Microvesicle components that may have a role in envenoming include ecto-5′-nucleotidase, a cell membrane protein that releases adenosine, and aminopeptidase N, a cell membrane protein that may modulate the action of many peptides. [ABSTRACT FROM AUTHOR]

The encyrtid parasitoid, Diversinervus elegans (Hymenoptera: Encyrtidae), is a natural enemy of the notorious scale pests belonging to the family of Coccidae. Venom containing a rich source of bioactive molecules is a key virulent factor used to regulate host physiology by parasitoids. Although knowledge regarding venom constituents accumulated from limited parasitoids has provided insights into their roles in host-parasitoid interaction, toxins involving in manipulating scale physiology remain sparsely documented. Here, a total number of 48 putative venom proteins were identified from D. elegans using an integrative transcriptomic and proteomic approach. The majority of them such as serine protease, esterase, and major royal jelly protein have been found in venom of other several parasitoid species. Several venom proteins including three novel proteins having unknown function were firstly revealed. Quantitative real time PCR analysis demonstrated that 16 venom genes displayed female-biased expression, which might be important for parasitism success. These data enrich our understanding of parasitoid venom evolution and diversity, and will undoubtedly help deciphering functional venom proteins as potential candidates for pest control. [ABSTRACT FROM AUTHOR]

The genus Conus comprises approximately 700 species of venomous marine cone snails that are highly efficient predators of worms, snails, and fish. In evolutionary terms, cone snails are relatively young with the earliest fossil records occurring in the Lower Eocene, 55 Ma. The rapid radiation of cone snail species has been accompanied by remarkably high rates of toxin diversification. To shed light on the molecular mechanisms that accompany speciation,we investigated the toxin repertoire of two sister species, Conus andremenezi and Conus praecellens, that were until recently considered a single variable species. A total of 196 and 250 toxin sequences were identified in the venom gland transcriptomes of C. andremenezi and C. praecellens belonging to 25 and 29 putative toxin gene superfamilies, respectively. Comparative analysis with closely (Conus tribblei and Conus lenavati) and more distantly related species (Conus geographus) suggests that speciation is associated with significant diversification of individual toxin genes (exogenes)whereas the expression pattern of toxin gene superfamilies within lineages remains largely conserved. Thus, changes within individual toxin sequences can serve as a sensitive indicator for recent speciation whereas changes in the expression pattern of gene superfamilies are likely to reflect more dramatic differences in a species' interaction with its prey, predators, and competitors. [ABSTRACT FROM AUTHOR]

Polybia paulista (Hymenoptera: Vespidae) is responsible for a high number of sting accidents and anaphylaxis events in Southeast Brazil, Argentina and Paraguay. The specific detection of allergy to the venom of this wasp is often hampered by the lack of recombinant allergens currently available for molecular diagnosis. Antigen 5 (~23 kDa) from P. paulista venom (Poly p 5) is a highly abundant and glycosylated allergenic protein that could be used for development of component-resolved diagnosis (CRD). Here, we describe the cloning and heterologous expression of the antigen 5 (rPoly p 5) from P. paulista venom using the eukaryotic system Pichia pastoris. The expression as a secreted protein yielded high levels of soluble rPoly p 5. The recombinant allergen was further purified to homogeneity (99%) using a two-step chromatographic procedure. Simultaneously, the native form of the allergen (nPoly p 5) was purified from the wasp venom by Ion exchange chromatography. The rPoly p 5 and nPoly p 5 were then submitted to a comparative analysis of IgE-mediated immunodetection using sera from patients previously diagnosed with sensitization to wasp venoms. Both rPoly p 5 and nPoly p 5 were recognized by specific IgE (sIgE) in the sera of the allergic individuals. The high levels of identity found between nPoly p 5 and rPoly p 5 by the alignment of its primary sequences as well as by 3-D models support the results obtained in the immunoblot. Overall, we showed that P. pastoris is a suitable system for production of soluble rPoly p 5 and that the recombinant allergen represents a potential candidate for molecular diagnosis of P.paulista venom allergy. [ABSTRACT FROM AUTHOR]

In regions at risk of scorpion envenomation, children remain the principal victims; they exhibit severe symptoms and represent a higher mortality rate compared to adults. The pathophysiology of envenomation is related to an excessive inflammatory response; however, no studies have identified the differences in immune responses to scorpion stings and mainly the mechanisms of inflammation between children and adults, which may be a determinant key of the susceptibility of children to scorpion envenomation. In this study, we compared the systemic (blood and lung) and the central (brain) inflammatory responses after injection of Androctonus australis hector ( Aah) venom to 7 and 21 postnatal days (pnds) and adult mice by subcutaneous route. Results revealed that 7 and 21 pnd mice were more sensitive to Aah venom than adults and presented also severe systemic and central inflammatory responses characterized by a high activation of immune cells, NO liberation, and lipid peroxidation. Lymphocyte levels were much lower in young animals than in adults; however, neutrophil levels seemed to be higher in immature mice. The antioxidant GSH and catalase levels were more reduced in 7 and 21 pnd mice compared to adults leading to more pronounced tissular alterations and edema formation in lung and brain. These findings show a relationship between the severity of the pathophysiological effects of Aah venom and the age. The vulnerability of immature animals to Aah venom might result from uncontrolled inflammatory response and central nervous system alterations. Data from the present study emphasize the need for the development of age-specific therapeutic modalities. [ABSTRACT FROM AUTHOR]

There is a rising interest in snake venoms proteins (SVPs) because these macromolecules are related to pharmacological properties that manifest themselves during poisoning and can lead to secondary microbial infections. Interestingly, researchers have somehow neglected the antimicrobial activity of SVPs. The aims of this study were: (i) to verify whether the venom of the Peruvian snake Bothriopsis oligolepis displays such activity; (ii) to isolate and identify some of its antimicrobial constituents. Liquid growth inhibition assays revealed that the crude venom inhibited the growth of Gram-positive and Gram-negative bacteria, but not of Candida species. Fractionation of the venom by anion-exchange chromatography provided fractions P2, P4 and P8 active against S. aureus . Fractionation of P2 or P8 by gel-filtration chromatography and of P4 by RP-HPLC furnished the sub-fractions P2-I, P8-II and P4-II, respectively, being those fractions active against S. aureus . Analyses of these sub-fractions by SDS-PAGE under denaturing/reducing conditions evidenced SVPs with 59–73, 27 and 14–28 kDa, respectively. Their in-gel tryptic digestion gave peptide fragments, whose sequencing by MALDI-TOF/MS followed by protein BLAST analysis allowed identifying PIII metalloprotease(s) [SVMP(s)] in P2-I, serine protease(s) [SVSP(s)] in P4-II and lectin(s) in P8-II. Detection of gelatinolytic activity in P2-I and P4-II reinforced the existence of PIII-SVMP(s) and SVSP(s), respectively. Activation of the coagulation cascade intrinsic pathway by P8-II (probably by interaction with factors IX and/or X as some snake C-type lectins do) supported the presence of C-type lectin(s). Altogether, these new findings reveal that the venom of the Peruvian snake Bothriopsis oligolepis displays antibacterial activity and that the isolated SVMP(s), SVSP(s) and C-type lectin(s) are associated to its ability to inhibit the growth of S. aureus . [ABSTRACT FROM AUTHOR]

Secretion of granular glands from the skin of amphibians is a fascinating resource of active substances, particularly for cancer therapy in clinical practice of Traditional Chinese Medicine. A variety of anti‑tumor peptides have been isolated from different toads and frogs; however, no anti‑tumor peptides are reported in toad venom of Bufo gargarizans. Firstly, soluble fraction from fresh toad venom (FTV) was compared with that from dried toad venom (DTV), using HPLC analysis. It was revealed that FTV has a different HPLC chromatography compared with DTV. Soluble fraction of FTV is more toxic to SH‑SY5Y cells than that of DTV, as evaluated by MTT assay. Secondly, it was identified that protein components from soluble fractions of FTV and DTV possess different patterns by SDS‑PAGE analysis, and proteins from FTV are also more toxic than that from DTV. Thirdly, an immobilized basic fibroblast growth factor (bFGF) affinity column was used to isolate bFGF‑binding components from soluble fraction of FTV, and it was identified that bFGF‑binding components prohibited bFGF‑dependent neurite growth of SH‑SY5Y cells. Finally, it was identified that bFGF‑binding components activated apoptosis via upregulation of caspase‑3 and caspase‑8 expression in SH‑SY5Y cells. These data suggest that FTV contains active components that interact with bFGF and activate apoptosis in SH‑SY5Y cells. [ABSTRACT FROM AUTHOR]

Scorpion envenomation is a common medical problem in many countries; it is an important cause of morbidity and mortality. The venom of Leiurus quinquestriatus (LQ) is responsible for a number of deaths in children and adults. It has been stated that specific pathophysiological conditions such as generation of oxygen free radicals may trigger the onset of multiple organ dysfunction; therefore, the present study aimed to assess the oxidative stress mediated by LQ crude venom and its effect on the biochemical parameters in rats. Adult male Albino rats (250 ± 30 g body weight) were divided into three groups (n = 5). In control group, rats were intraperitoneally (ip) injected with 50 μL saline solution. Groups 2 and 3 were ip injected with 0.1 mg/kg and 0.2 mg/kg body weight of crude venom, respectively. Blood samples and liver tissues were harvested 1, 2 and 4 h post-injection. Serum levels of glucose, cholesterol, creatinine, urea, uric acid and malondialdehyde increased significantly in envenomed animals within 1, 2 and 4 h post-injection, compared to controls. However, the levels of total serum protein, albumin, globulin and triglycerides as well as catalase, glutathione peroxidase and super oxide dismutase in envenomed rats were significantly decreased compared to controls. We can conclude that LQ crude venom induces oxidative stress via reduction of antioxidant systems and alters some biochemical parameters of envenomed rats. [ABSTRACT FROM AUTHOR]

Rattlesnakes use prey chemical cues for ambush site selection and for relocating envenomated (E) prey following a predatory strike. The ability to discriminate between E and non-envenomated (NE) prey cues has been widely studied in rattlesnake species that produce type I venoms, which show high levels of snake venom metalloproteinase (SVMP) activity and low lethal toxicity [lethal dose which kills 50% of test animals (LD) >1.0 µg/g]. However, E vs. NE prey discrimination studies have not been conducted on rattlesnake species that produce a type II venom that consists of low SVMP activity and high lethal toxicity (LD <1.0 µg/g). In the current study, long-term captive Crotalus oreganus concolor, which produce a type II venom, were tested for their ability to discriminate between chemical cues of natural ( Sceloporus undulatus and Peromyscus maniculatus) and non-natural ( Hemidactylus frenatus and Mus musculus) prey cues, as well as for their ability to discriminate between E and NE mouse carcasses, when prey envenomation occurred by a conspecific. Snakes showed significant levels of tongue flicking towards the chemical extracts of P. maniculatus and M. musculus, suggesting that C. oreganus concolor exhibit both innate and experience-based plasticity in response to prey chemical cues. In addition, C. oreganus concolor were able to discriminate between E and NE prey sources, when envenomation occurred by a conspecific, indicating that a type II venomous species can also discriminate between E and NE chemical cues. [ABSTRACT FROM AUTHOR]

Compounds activating γ-aminobutyric acid type A receptor were isolated from the toad Bufo bufo venom as a result of chromatographic separation. Analysis of the structure of these compounds by mass spectrometry and nuclear magnetic resonance showed that they are arginine derivatives of dicarboxylic acids and represent suberylarginine, pimeloylarginine, and adipoylarginine. [ABSTRACT FROM AUTHOR]

Cnidarian envenomations are the leading cause of severe and lethal human sting injuries from marine life. The total amount of venom discharged into sting-site tissues, sometimes referred to as "venom load", has been previously shown to correlate with tentacle contact length and sequelae severity. Since <1% of cnidae discharge upon initial tentacle contact, effective and safe removal of adherent tentacles is of paramount importance in the management of life-threatening cubozoan stings. We evaluated whether common rinse solutions or scraping increased venom load as measured in a direct functional assay of venom activity (hemolysis). Scraping significantly increased hemolysis by increasing cnidae discharge. For Alatina alata, increases did not occur if the tentacles were first doused with vinegar or if heat was applied. However, in Chironex fleckeri, vinegar dousing and heat treatment were less effective, and the best outcomes occurred with the use of venom-inhibiting technologies (Sting No More® products). Seawater rinsing, considered a "no-harm" alternative, significantly increased venom load. The application of ice severely exacerbated A. alata stings, but had a less pronounced effect on C. fleckeri stings, while heat application markedly reduced hemolysis for both species. Our results do not support scraping or seawater rinsing to remove adherent tentacles. [ABSTRACT FROM AUTHOR]

Hemoscorpius lepturus is the most medically important scorpion in Iran. The clinical signs of H. lepturus envenomation are remarkably similar to those reported for brown spiders, including dermonecrosis, hematuria, renal failure and even death. The lethality and toxicity of brown spiders' venom have been attributed to its phospholipase D activity. This study aims to identify a phospholipase D with possible lethality and dermonecrotic activity in H. lepturus venom. In this study, a cDNA library of the venom glands was generated by Illumina RNA sequencing. Phospholipase D (PLD) from H. lepturus was characterized according to its significant similarity with PLDs from brown spiders. The main chain designated as Hl-RecPLD1 (the first recombinant isoform of H. lepturus PLD) was cloned, expressed and purified. Sphingomyelinase, dermonecrotic and lethal activities were examined. Hl-PLD1 showed remarkable sequence similarity and structural homology with PLDs of brown spiders. The conformation of Hl-PLD1 was predicted as a "TIM beta/alpha-barrel". The lethal dose 50 (LD50) and dermonecrotic activities of Hl-RecPLD1 were determined as 3.1 μg/mouse and 0.7 cm2 at 1 μg respectively. It is the first report indicating that a similar molecular evolutionary mechanism has occurred in both American brown spiders and this Iranian scorpion. In conclusion, Hl-RecPLD1 is a highly active phospholipase D, which would be considered as the lethal dermonecrotic toxin in H. lepturus venom. [ABSTRACT FROM AUTHOR]

Contact with Lonomia caterpillars can cause a hemorrhagic syndrome. In Brazil, Lonomia obliqua and Lonomia achelous are known to cause this venom-induced disease. In the Brazilian Amazon, descriptions of this kind of envenomation are scarce. Herein, we report a severe hemorrhagic syndrome caused by Lonomia envenomation in the Amazonas state, Western Brazilian Amazon. The patient showed signs of hemorrhage lasting 8 days and required Lonomia antivenom administration, which resulted in resolution of hemorrhagic syndrome. Thus, availability of Lonomia antivenom as well as early antivenom therapy administration should be addressed across remote areas in the Amazon. [ABSTRACT FROM AUTHOR]

Context: Although rare, coral snake envenomation is a serious health threat in Brazil, because of the highly neurotoxic venom and the scarcely available antivenom. The major bottleneck for antivenom production is the low availability of venom. Furthermore, the available serum is not effective against all coral snake species found in Brazil. An alternative to circumvent the lack of venom for serum production and the restricted protection of the actually available antivenom would be of great value. We compared the Brazilian coral snake and mono and polyvalent Australian antivenoms in terms of reactivity and protection. Methods: The immunoreactivity of venoms from 9 coral snakes species were assayed by ELISA and western blot using the Brazilian Micrurus and the Australian pentavalent as well as monovalent anti-Notechis, Oxyuranus and Pseudechis antivenoms. Neutralization assays were performed in mice, using 3 LD50 of the venoms, incubated for 30 minutes with 100 μL of antivenom/animal. Discussion: All the venoms reacted against the autologous and heterologous antivenoms. Nevertheless, the neutralization assays showed that the coral snake antivenom was only effective against M. corallinus, M. frontalis, M. fulvius, M. nigrocinctus and M. pyrrhocryptus venoms. On the other hand, the Australian pentavalent antivenom neutralized all venoms except the one from M. spixii. A combination of anti-Oxyuranus and Pseudechis monovalent sera, extended the protection to M. altirostris and, partially, to M. ibiboboca. By adding Notechis antivenom to this mixture, we obtained full protection against M. ibiboboca and partial neutralization against M. lemniscatus venoms. Conclusions: Our findings confirm the limited effectiveness of the Brazilian coral snake antivenom and indicate that antivenoms made from Australian snakes venoms are an effective alternative for coral snake bites in South America and also in the United States were coral snake antivenom production has been discontinued. [ABSTRACT FROM AUTHOR]

PURPOSE: We aimed to describe ultrasonography (US)-guided percutaneous aspiration thrombectomy in pregnant women with iliofemoral deep vein thrombosis. METHODS: This study included nine pregnant women with acute and subacute iliofemoral deep vein thrombosis, who were severe symptomatic cases with massive swelling and pain of the leg. Patients were excluded from the study if they had only femoropopliteal deep vein thrombosis or mild symptoms of deep vein thrombosis. US-guided percutaneous aspiration thrombectomy was applied to achieve thrombus removal and uninterrupted venous flow. The treatment was considered successful if there was adequate venous patency and symptomatic relief. RESULTS: Complete or significant thrombus removal and uninterrupted venous flow from the puncture site up to the iliac veins were achieved in all patients at first intervention. Complete relief of leg pain was achieved immediately in seven patients (77.8%). Two patients (22.2%) had a recurrence of thrombosis in the first week postintervention. One of them underwent a second intervention, where percutaneous aspiration thrombectomy was performed again with successful removal of thrombus and establishment of in line flow. Two patients were lost to follow-up after birth. None of the remaining seven patients had rethrombosis throughout the postpartum period. Symptomatic relief was detected clinically in these patients. CONCLUSION: Endovascular treatment with US-guided percutaneous aspiration thrombectomy can be considered as a safe and effective way to remove thrombus from the deep veins in pregnant women with acute and subacute iliofemoral deep vein thrombosis. [ABSTRACT FROM AUTHOR]

Background: Snakebite is a major public health problem in agricultural communities in the tropics leading to acute local and systemic impairments with resultant disabilities. Snakebite related long-term musculoskeletal disabilities have been a neglected area of research. We conducted a population-based, cross-sectional study in an agricultural community to describe the chronic musculoskeletal disabilities of snake envenoming. Methodology/Principal Findings: A sample representative of residents of a single district in a region of high incidence of snake envenoming was recruited to identify ever snakebite victims. They were evaluated for chronic musculoskeletal disabilities that had developed immediately or within four weeks after the snakebite and persisted over three months. In-depth interviews, validated musculoskeletal functional assessment criteria and specialists’ examinations were utilised. Among the 816 victims, 26 (3.2%, 95% confidence interval: 2.2–4.6%) had musculoskeletal disabilities, persisting on average for 13.4 years (SD = 14.4). The disabilities were mostly in lower limbs (61.5%) and ranged from swelling (34.6%), muscle wasting (46.1%), reduced motion (61.5%), reduced muscle power (50%), impaired balance (26.9%), chronic non-healing ulcers (3.85%), abnormal gait (3.85%), fixed deformities (19.2%) to amputations (15.4%). Based on disability patterns, six snakebite-related musculoskeletal syndromes were recognised. The offending snakes causing disabilities were cobra (30.8%), Russell’s viper (26.9%) and hump-nosed viper (7.7%). Cobra bites manifested muscle wasting (87.5%), reduced muscle power (87.5%), joint stiffness (62.5%) and deformities (37.5%) while viper bites manifested impaired balance (42.8%), pain (71.4%) and swelling (71.4%). Conclusions/Significance: Snakebite envenoming is associated with considerable long-term musculoskeletal disabilities. Facilities for specialized care and rehabilitation need to be established in high risk areas. [ABSTRACT FROM AUTHOR]

We have previously demonstrated that Phoneutria nigriventer venom (PNV) causes blood-brain barrier (BBB) breakdown, swelling of astrocytes end-feet and fluid permeation into brain interstitium in rats. Caveolae and water channels respond to BBB alterations by co-participation in shear stress response and edema formation/resolution. Herein, we showed post-natal developmental-related changes of two BBB-associated transporter proteins: the endothelial caveolin-1 (Cav-1), the major scaffolding protein from caveolae frame, and the astroglial aquaporin-4 (AQP4), the main water channel protein expressed in astrocytic peri-vascular end-feet processes, in the hippocampus of rats intraperitoneally-administered PNV. Western blotting protein levels; immunohistochemistry (IHC) protein distribution in CA1, CA2, and CA3 subfields; and gene expression by Real Time-Polymerase Chain Reaction (qPCR) were assessed in post-natal Day 14 (P14) and 8-10-week-old rats over critical periods of envenomation. The intensity and duration of the toxic manifestations indicate P14 neonate rats more vulnerable to PNV than adults. Histologically, the capillaries of P14 and 8-10-week-old rats treated with PNV showed perivascular edema, while controls did not. The intensity of the toxic manifestations in P14 decreases temporally (2 > 5 > 24 h), while inversely the expression of AQP4 and Cav-1 peaked at 24 h when clinically PNV-treated animals do not differ from saline controls. IHC of AQP4 revealed that hippocampal CA1 showed the least expression at 2 h when toxic manifestation was maximal. Subfield IHC quantification revealed that in P14 rats Cav-1 peaked at 24 h when toxic manifestations were absent, whereas in 8-10-week-old rats Cav-1 peaked at 2 h when toxic signs were highest, and progressively attenuated such increases until 24 h, remaining though significantly above baseline. Considering astrocyte-endothelial physical and functional interactions, we hypothesize that age-related modulations of AQP4 and Cav-1 might be linked both to changes in functional properties of astrocytes during post-natal development and in the BBB breakdown induced by the venom of P. nigriventer. [ABSTRACT FROM AUTHOR]

Venom secretions from snakes, scorpions, spiders and bees, have been widely applied in traditional medicine and current biopharmaceutical research. Possession of anticancer potential is another novel discovery for animal venoms and toxins. An increasing number of studies have shown the anticancer effects of venoms and toxins of snakes, and scorpions in vitro and in vivo, which were achieved mainly through the inhibition of cancer growth, arrest of cell cycle, induction of apoptosis and suppression of cancer metastasis. However, more evidence is needed to support this concept and the mechanisms of anticancer actions are not clearly understood. The present review is focused on the recant updates on anticancer venom research. [ABSTRACT FROM AUTHOR]

Thousands suffer poisonous snake bite, often from defibrinogenating species annually. Three rattlesnake species in particular, the timber rattlesnake, Eastern diamondback rattlesnake, and Southern Pacific rattlesnake, cause clinically relevant hypofibrinogenemia via thrombin-like activity in their venom. It has been demonstrated that iron (Fe) and carbon monoxide (CO) change the ultrastructure of plasma thrombi and improve coagulation kinetics. Thus, the present investigation sought to determine if pretreatment of plasma with Fe and CO could attenuate venom-mediated catalysis of fibrinogen via thrombin-like activity. Human plasma was pretreated with ferric chloride (0–10 μM) and CO-releasing molecule-2 (0–100 μM) prior to exposure to 2.5–10 μg/ml of venom obtained from the aforementioned three species of rattlesnake. Coagulation kinetics were determined with thrombelastography. All three snake venoms degraded plasmatic coagulation kinetics to a significant extent, especially diminishing the speed of clot growth and strength. Pretreatment of plasma with Fe and CO completely abrogated the effects of all three venoms on coagulation kinetics. Further in vitro investigation of other pit viper venoms that possess thrombin-like activity is indicated to see if there is significant conservation of venom enzymatic target recognition of specific amino acid sequences such that Fe and CO can reliably attenuate venom-mediated catalysis of fibrinogen. These data also serve as a rationale for future preclinical investigation. [ABSTRACT FROM AUTHOR]

Background Venom immunotherapy is efficient to desensitize people suffering from insect sting allergies. However, the numerous injections required over several years and important risks of severe side reactions complicate the widespread use of immunotherapy. In the search for novel approaches to blunt the overwhelming pro-allergic Th2 response, we evaluated the therapeutic efficacy of a treatment based on a denatured form of the major allergen, phospholipase A2, associated with microbubbles ( PLA2denat- MB) in a mouse model of honeybee venom allergy. Methods Antibodies measured by ELISA, T-cell responses assessed by CFSE-based proliferation assays and ELISA, and basophil degranulation were examined after PLA2denat- MB-based therapeutic treatment of sensitized mice. Mice were challenged with a lethal dose of PLA2 to evaluate protection against anaphylaxis. Results Therapeutic subcutaneous administration of two different PLA2denat- MB formulations, in contrast to PLA2denat alone, reduced allergic symptoms and protected all mice from anaphylaxis-mediated death after allergen challenge. At the functional level, the use of PLA2denat decreased IgE-mediated basophil degranulation as compared to the native form of the allergen. In comparison with PLA2denat alone, both PLA2denat- MB formulations decreased allergen-specific Th2 CD4 T-cell reactivity. At the mechanistic level, PLA2denat- MB containing 20% palmitic acid and PEG induced PLA2-specific IgA and increased Foxp3+ Treg frequencies and TGF-β production, whereas the formulation bearing 80% palmitic acid triggered the production of IFN-γ, IgG2a, and IgG3. Conclusions In contrast to conventional PLA2 subcutaneous immunotherapy, the therapeutic administration of PLA2- MB treatment to mice that already had established allergy to PLA2 protects all subsequently challenged animals. [ABSTRACT FROM AUTHOR]

Objective: Intra-arterial injection of Mesobuthus tamulus (BT) venom produces reflex vasosensory responses modulating cardiorespiratory parameters in albino rats. The present study was conducted to understand the role of kinin receptors in modulating vasosensory reflexes evoked by BT venom. Materials and Methods: In urethane-anesthetized rats, tracheostomy was performed to keep the airway patent. The femoral artery was cannulated proximally, as well as distally, to record the blood pressure (BP) and to inject the chemicals, respectively. Electrocardiographic and respiratory excursions were recorded to compute the heart rate (HR) and respiratory rate (RR). A group of animals was pretreated with saline/kinin receptor antagonists intra-arterially (B1/B2 receptor antagonists) before the injection of venom. Results: After intra-arterial injection of BT venom (1 mg/kg), there was an immediate increase in RR, which reached to 40% within 30 s, followed by a decrease of 40%. Further, there was sustained increase in RR (50%) up to 60 min. The BP started to increase at 40 s, peaking at 5 min (50%), and remained above the initial level up to 60 min. The bradycardiac response started after 5 min which peaked (50% of initial) at 25 min and remained at that level up to 60 min. In B1 receptor antagonist (des-Arg) pretreated animals, venom-induced cardiovascular responses were attenuated (by 20-25% in mean arterial pressure and HR) significantly but not in B2 receptor antagonist (Hoe-140) pretreated animals. Either of the antagonists failed to alter the RR responses. Conclusions: BT venom-induced vasosensory reflex responses modulating cardiovascular parameters are mediated via B1-kinin receptors in anesthetized rats. [ABSTRACT FROM AUTHOR]

Bites from genus Phoneutria (Ctenidae, Araneomorpha) are the second most frequent source of spider accidents in Southeast Brazil. Severe envenoming from Phoneutria nigriventer produces vision disturbance, tremor and convulsion, suggesting that the CNS is involved; however, the mechanisms by which P. nigriventer venom (PNV) affects the CNS remain poorly understood. The present study aimed to investigate whether PNV directly impairs astrocytes. Cultured astrocytes were exposed to PNV, and intracellular Ca 2+ release and signaling were measured (Fura-2/AM), Na + /K + -ATPase and Toll-like receptor 4 (TLR4) involvement were investigated, actin filaments were stained (Alexa™ 488-conjugated phalloidin probe), the G-actin/F-actin ratio was determined, and the expression level of connexin 43 (Cx43) was assessed. Incubation in Ca 2+ -free buffer did not change the Ca 2+ responses. However, pre-incubation in thapsigargin/caffeine completely abolished these responses, suggesting that PNV-evoked Ca 2+ transients were from intracellular Ca 2+ stores. Pretreatment with a Na + /K + -ATPase antagonist (ouabain) or a TLR4 antagonist (LPS-RS) decreased or increased the Ca 2+ -evoked transients, respectively. Astrocytes showed altered actin filament structure after PNV exposure. PNV treatment increased the expression levels of Na + /K + -ATPase and Cx43 but decreased those of TLR4. The present results suggest that PNV directly affects astrocytes. Na + /K + -ATPase may thus represent a more specific drug target for controlling the neurotoxicity of PNV. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS), such as superoxide and hydrogen peroxide, play essential roles in physiological plasticity and are also involved in the pathogenesis of persistent pain. Roles of peripheral and spinal ROS in pain have been well established, but much less is known about ROS in the amygdala, a brain region that plays an important role in pain modulation. The present study explored the contribution of ROS in the amygdala to bee venom (BV)-induced pain behaviors. Our data show that the amygdala is activated following subcutaneous BV injection into the left hindpaw, which is reflected in the increased number of c-Fos positive cells in the central and basolateral amygdala nuclei in the right hemisphere. Stereotaxic administration of a ROS scavenger (tempol, 10 mM), NADPH oxidase inhibitor (baicalein, 5 mM) or lipoxygenase inhibitor (apocynin, 10 mM) into the right amygdala attenuated the BV-induced spontaneous licking and lifting behaviors, but had no effect on BV-induced paw flinch reflexes. Our study provides further evidence for the involvement of the amygdala in nociceptive processing and pain behaviors, and that ROS in amygdala may be a potential target for treatment strategies to inhibit pain. [ABSTRACT FROM AUTHOR]

Formation of correct disulfide bonds in the endoplasmic reticulum is a crucial step for folding proteins destined for secretion. Protein disulfide isomerases (PDIs) play a central role in this process. We report a previously unidentified, hypervariable family of PDIs that represents the most diverse gene family of oxidoreductases described in a single genus to date. These enzymes are highly expressed specifically in the venom glands of predatory cone snails, animals that synthesize a remarkably diverse set of cysteine-rich peptide toxins (conotoxins). Enzymes in this PDI family, termed conotoxin-specific PDIs, significantly and differentially accelerate the kinetics of disulfide-bond formation of several conotoxins. Our results are consistent with a unique biological scenario associated with protein folding: The diversification of a family of foldases can be correlated with the rapid evolution of an unprecedented diversity of disulfide-rich structural domains expressed by venomous marine snails in the superfamily Conoidea. [ABSTRACT FROM AUTHOR]

Cyanea nozakii Kishinouy e ( C. nozakii), a giant cnidarian of the class Scyphomedusae, order Semaeostomeae and family Cyaneidae, is widely distributed in the East China Sea, the Yellow Sea and the Bohai Sea, and is abundant from late summer to early autumn. Venom produced by C. nozakii during mass agglomerations can contaminate seawater resulting in death of the halobios and seriously damage commercial fisheries. Swimmers and fishermen commonly suff er painful stings from this jellyfish, resulting in local edema, tingling, breathing difficulties, depressed blood pressure and even death. Such effects arise from the complex mixture of biologically active molecules that make up jellyfish venom. In the present study, the hemolytic activity of venom from tentacles of C. nozakii and factors aff ecting its activity were assayed. The HU ( defined as the amount of protein required to lyse 50 % of erythrocytes) of the venom against dove and chicken erythrocytes was 34 and 59 μg/mL, respectively. Carboxylmethyl chitosan and glycerol could increase hemolytic activity at concentrations greater than 0.06% and 0.2 mol/L, respectively. [ABSTRACT FROM AUTHOR]

A transcriptomic analysis of the saliva of T. pallidipennis together with a short proteomic analysis were carried out to reveal novel primary structures of the lipocalin/triabin protein families in this reduviid. Although triabins share some structural characteristics to lipocalins and they are classified as in the calcyn/lipocalin superfamily, triabins differ from lipocalins in the direction of β-strands in the general conformation of the β-barrel. The triabin protein family encompasses a wide variety of proteins, which disrupt the hemostasis of warm-blooded animals. Likewise, the function of proteins classified as triabins includes proteins that are carriers of small molecules, protease inhibitors, binders of specific cell-surface receptors as well as proteins that form complexes with other macromolecules. For example, triabin and pallidipin from the saliva of T. pallidipennis are thrombin and platelet aggregation inhibitors, respectively; triplatin from T. infestans binds to thromboxane A2; and nitrophorin from Rhodnius prolixus carries nitric oxide. Therefore, based on 42 new transcriptome sequences of triabins from the salivary glands of T. pallidipennis reported at present, and on triabin sequences of other American hematophagous reduviids already reported in the literature, subfamilies of triabins were proposed following phylogenetic analyses and functional characterization of triabin members. Eight subfamilies of proteins were recognized with known functions, which were the nitrophorin and amine binding proteins, Rhodnius prolixus aggregation inhibitor, triafestin, triatin, dipetalodipin and pallidipin, triplatin and infestilin, dimiconin and triabin, and procalin subfamilies. Interestingly, 70% of the analyzed sequences came from these eight subfamilies because there was no biological function associated with them, implying the existence of a vast number of proteins with potential novel biological activities. [ABSTRACT FROM AUTHOR]

The primary functions of venoms from solitary and social wasps are different. Whereas most solitary wasps sting their prey to paralyze and preserve it, without killing, as the provisions for their progeny, social wasps usually sting to defend their colonies from vertebrate predators. Such distinctive venom properties of solitary and social wasps suggest that the main venom components are likely to be different depending on the wasps' sociality. The present paper reviews venom components and properties of the Aculeata hunting wasps, with a particular emphasis on the comparative aspects of venom compositions and properties between solitary and social wasps. Common components in both solitary and social wasp venoms include hyaluronidase, phospholipase A2, metalloendopeptidase, etc. Although it has been expected that more diverse bioactive components with the functions of prey inactivation and physiology manipulation are present in solitary wasps, available studies on venom compositions of solitary wasps are simply too scarce to generalize this notion. Nevertheless, some neurotoxic peptides (e.g., pompilidotoxin and dendrotoxin-like peptide) and proteins (e.g., insulin-like peptide binding protein) appear to be specific to solitary wasp venom. In contrast, several proteins, such as venom allergen 5 protein, venom acid phosphatase, and various phospholipases, appear to be relatively more specific to social wasp venom. Finally, putative functions of main venom components and their application are also discussed. [ABSTRACT FROM AUTHOR]

A novel conotoxin, named as PiVIIA, was isolated from the venom of Conus princeps, a marine predatory cone snail collected in the Pacific Southern Coast of Mexico. Chymotryptic digest of the S-alkylated peptide in combination with liquid chromatography coupled to tandem mass spectrometry, were used to define the sequencing of this peptide. Eleven N-terminal amino acids were verified by automated Edman degradation. PiVIIA is a 25-mer peptide (CDAOTHYCTNYW CCSGYC HSHCW) with six cysteine residues forming three disulphide bonds, a hydroxyproline (O) and two gamma carboxyglutamic acid (γ) residues. Based on the arrangement of six Cys residues (C-C-CC-C-C), this conotoxin might belong to the O2-superfamily. Moreover, PiVIIA has a conserved motif (- CCS-) that characterizes -conotoxins from molluscivorous Conus. Peptide PiVIIA has 45% sequence identity with -PnVIIA-the prototype of this family. Biological activity of PiVIIA was assessed by voltage-clamp recording in rat dorsal root ganglion neurons. Perfusion of PiVIIA in the μM range produces a significant increase in the Ca2+ currents, without significantly modifying the Na+, K+ or proton-gated acid sensing ionic currents. These results indicate that PiVIIA is a new conotoxin whose activity deserves further studies to define its potential use as a positive modulator of neuronal activity. [ABSTRACT FROM AUTHOR]

Drug delivery across the blood-brain barrier (BBB) is a formidable challenge for therapies targeting the central nervous system. Although BBB shuttle peptides enhance transport into the brain non-invasively, their application is partly limited by lability to proteases. The present study proposes the use of cyclic peptides derived from venoms as an affordable way to circumvent this drawback. Apamin, a neurotoxin from bee venom, was minimized by reducing its complexity, toxicity, and immunogenicity, while preserving brain targeting, active transport, and protease resistance. Among the analogues designed, the monocyclic lactambridged peptidomimetic MiniAp-4 was the most permeable. This molecule is capable of translocating proteins and nanoparticles in a human-cell-based BBB model. Furthermore, MiniAp-4 can efficiently deliver a cargo across the BBB into the brain parenchyma of mice. [ABSTRACT FROM AUTHOR]

OBJECTIVE:The aim of the study was to assess immune response to honeybee venom in relation to the degree of exposure, time after a sting and clinical symptoms. MATERIALS AND METHOD:Fifty-four volunteers were divided into 2 groups: beekeepers and a control group. The serum levels of total IgE (tIgE), bee venom-specific IgE (venom sIgE), phospholipase A2-specific IgE (phospholipase A2 sIgE), tryptase and venom-specific IgG4 (venom sIgG4) were determined. In beekeepers, diagnostic tests were performed within 3 hours following a sting and were repeated after a minimum of 6 weeks from the last sting. In individuals from the control group, the tests were performed only once, without a sting. RESULTS:The tests showed significant differences in venom sIgE (beekeepers' median = 0.34 kUA/l, control group median = 0.29 kUA/l), baseline serum tryptase (beekeepers' median = 4.25 µg/l, control group median = 2.74 µg/l) and sIgG4 (beekeepers' median = 21.2 mgA/l, control group median = 0.14 mgA/l), confirming higher levels of the tested substances in the beekeepers than in the control group. A significant positive correlation was observed between phospholipase A2 sIgE concentration and severity of clinical symptoms after a sting in the group of beekeepers. It was also demonstrated that the clinical symptoms after a sting became less severe with increasing age of the beekeepers. CONCLUSIONS:The differences in the immune response to a bee sting between the beekeepers and individuals not exposed to bees were probably due to the high exposure of the beekeepers to honeybee venom allergens. This may suggest a different approach to the bee venom allergy diagnostic tests in this occupational group. [ABSTRACT FROM AUTHOR]