Hornet Venom Research Articles

A Designed Analog of an Antimicrobial Peptide, Crabrolin, Exhibits Enhanced Anti-Proliferative and In Vivo Antimicrobial Activity.

Antimicrobial peptides have gradually attracted interest as promising alternatives to conventional agents to control the worldwide health threats posed by antibiotic resistance and cancer. Crabrolin is a tridecapeptide extracted from the venom of the European hornet (Vespa crabro). Its antibacterial and anticancer potentials have been underrated compared to other peptides discovered from natural resources. Herein, a series of analogs were designed based on the template sequence of crabrolin to study its structure-activity relationship and enhance the drug's potential by changing the number, type, and distribution of charged residues. The cationicity-enhanced derivatives were shown to have improved antibacterial and anticancer activities with a lower toxicity. Notably, the double-arginine-modified product, crabrolin-TR, possessed a potent capacity against Pseudomonas aeruginosa (minimum inhibitory concentration (MIC) = 4 μM), which was around thirty times stronger than the parent peptide (MIC = 128 μM). Furthermore, crabrolin-TR showed an in vivo treatment efficacy in a Klebsiella-pneumoniae-infected waxworm model and was non-toxic under its maximum MBC value (MIC = 8 μM), indicating its therapeutic potency and better selectivity. Overall, we rationally designed functional peptides by progressively increasing the number and distribution of charged residues, demonstrating new insights for developing therapeutic molecules from natural resources with enhanced properties, and proposed crabrolin-TR as an appealing antibacterial and anticancer agent candidate for development.

Endothelial dysfunction of the cornea after exposure to sprayed venom from hornets

Purpose Ocular injuries due to Hymenoptera venom are uncommon and most injuries occur on the ocular surface. We reported two rare cases of corneal endothelial damage caused by hornet venom that was sprayed, not injected, through stinging in the eye. Observations Case 1: A 57-year-old male patient was injured when a hornet sprayed venom into his left eye. He was referred to our hospital because the edoema and epithelial erosion of the cornea persisted. The patient presented with bullous keratopathy, asymmetrical iris atrophy, irreversible mydriasis, and glaucoma. His cataract progressed, and his best-corrected visual acuity was 0.03. Cataract surgery was performed after anti-inflammatory treatment with steroids, and Descemet-stripping automated endothelial keratoplasty was performed 6 months later. The patient recovered well postoperatively: his best-corrected visual acuity improved to 1.0 and he continued his glaucoma treatment. Case 2: A 75-year-old male patient had damage to his corneal epithelium, severe conjunctivitis, and conjunctival edoema when sprayed hornet venom entered his left eye. At initial presentation, the corneal endothelial cell density had decreased to 1042 cells/mm2. The conjunctival sac was washed, and steroid and topical antibacterial instillations were administered. His best-corrected visual acuity improved from 0.07 at the initial visit to 0.5. However, the corneal opacification and glaucoma persisted, and 3 months later the corneal endothelial cell density decreased to 846 cells/mm2. Conclusions and importance Corneal injuries caused by sprayed hornet venom are rare; however, they can cause intense anterior chamber inflammation and severe, irreversible corneal endothelial damage. In such cases, prompt initial treatment, the administration of adequate anti-inflammatory medication, and careful evaluation of the corneal endothelium are required.

Characterization of the Molecular Diversity and Degranulation Activity of Mastoparan Family Peptides from Wasp Venoms.

Wasp stings have become an increasingly serious public health problem because of their high incidence and mortality rates in various countries and regions. Mastoparan family peptides are the most abundant natural peptides in hornet venoms and solitary wasp venom. However, there is a lack of systematic and comprehensive studies on mastoparan family peptides from wasp venoms. In our study, for the first time, we evaluated the molecular diversity of 55 wasp mastoparan family peptides from wasp venoms and divided them into four major subfamilies. Then, we established a wasp peptide library containing all 55 known mastoparan family peptides by chemical synthesis and C-terminal amidation modification, and we systematically evaluated their degranulation activities in two mast cell lines, namely the RBL-2H3 and P815 cell lines. The results showed that among the 55 mastoparans, 35 mastoparans could significantly induce mast cell degranulation, 7 mastoparans had modest mast cell degranulation activity, and 13 mastoparans had little mast cell degranulation activity, suggesting functional variation in mastoparan family peptides from wasp venoms. Structure-function relationship studies found that the composition of amino acids in the hydrophobic face and amidation in the C-terminal region are critical for the degranulation activity of mastoparan family peptides from wasp venoms. Our research will lay a theoretical foundation for studying the mechanism underlying the degranulation activity of wasp mastoparans and provide new evidence to support the molecular design and molecular optimization of natural mastoparan peptides from wasp venoms in the future.

Molecular diagnostics and inhibition of cross-reactive carbohydrate determinants in Hymenoptera venom allergy.

The composition of venom extracts, cross-reactive carbohydrate determinants (CCD) and the component-resolved diagnostics (CRD) are important fields of investigation. IgE-reactivity to CCD complicates the interpretation of IgE to Hymenoptera venoms, especially in patients with multiple-positivity. We analyzed the clinical importance of CRD and CCD-inhibition for selection of allergens for venom immunotherapy (VIT). In 71 patients, we measured specific IgE (sIgE) to honeybee venom (HBV), wasp venom (WV), hornet venom (HV), CCD, and recombinant allergens: phospholipase A2 (rApi m 1), hyaluronidase (rApi m 2), icarapin (rApi m 10), antigen 5 (rVes v 5), and phospholipase A1 (Immunoblot). In 29/71 HBV/WV/HV/CCD-positive patients CCD-inhibition was performed. According to CRD and CCD-inhibition, we identified true sensitization and defined groups of multiple-positive patients who needed CCD-inhibition before starting VIT. sIgE-rApi m 1, sIgE-rApi m 2, and sIgE-rApi m 10 were detected in 65.7%, 68.4%, and 58%, respectively. In HBV allergic patients, CRD sensitivity was 86.8%. In WV allergic patients, sensitivity of sIgE-rVes v 5 was 94%. True multiple-sensitization was found in 44.8% of HBV/WV/HV/CCD-positive patients after CCD-inhibition. Patients with multiple venom- and CCD-positivity had more frequent severe allergic reactions (p<0.001). CCD-inhibition was helpful in HBV/WV/HV/CCD-positive patients who were negative to all tested recombinant honeybee allergens. Persistence of HBV-positivity after CCD-inhibition requires CRD to other honeybee recombinant allergens. CRD, using a profile of five most important recombinant allergens and CCD, has a high sensitivity for the diagnosis of venom allergy, especially in patients positive to several venom extracts. CRD and CCD-inhibition are helpful to reveal the clinically relevant, true sensitization and improve the selection of venoms for long-lasting VIT.

Stings on wings: Proteotranscriptomic and biochemical profiling of the lesser banded hornet (Vespa affinis) venom.

Distinct animal lineages have convergently recruited venoms as weaponry for prey capture, anti-predator defence, conspecific competition, or a combination thereof. Most studies, however, have been primarily confined to a narrow taxonomic breadth. The venoms of cone snails, snakes, spiders and scorpions remain particularly well-investigated. Much less explored are the venoms of wasps (Order: Hymenoptera) that are infamous for causing excruciating and throbbing pain, justifying their apex position on Schmidt's pain index, including some that are rated four on four. For example, the lesser banded wasp (V. affinis) is clinically important yet has only been the subject of a few studies, despite being commonly found across tropical and subtropical Asia. Stings from these wasps, especially from multiple individuals of a nest, often lead to clinically severe manifestations, including mastocytosis, myasthenia gravis, optic neuropathy, and life-threatening pathologies such as myocardial infarction and organ failure. However, their venom composition and activity remain unexplored in the Indian subcontinent. Here, we report the proteomic composition, transcriptomic profile, and biochemical and pharmacological activities of V. affinis venom from southern India. Our findings suggest that wasp venoms are rich in diverse toxins that facilitate antipredator defence. Biochemical and pharmacological assessments reveal that these toxins can exhibit significantly higher activities than their homologues in medically important snakes. Their ability to exert potent effects on diverse molecular targets makes them a treasure trove for discovering life-saving therapeutics. Fascinatingly, wasp venoms, being evolutionarily ancient, exhibit a greater degree of compositional and sequence conservation across very distant populations/species, which contrasts with the patterns of venom evolution observed in evolutionarily younger lineages, such as advanced snakes and cone snails.

A Case Report of Anaphylactic Shock Due to Hornet Sting with Multiple Organ Dysfunction Complications

BACKGROUND: Hornet venom has been recognized to induce lethal systemic effects such as anaphylaxis shock, bronchospasm, acute kidney or liver injury, disseminated intravascular coagulation (DIC), cardiovascular collapse, and even death. It consists of several enzymes and polypeptides with low molecular weights. It has been reported to contain the enzymes phospholipase A2, hyaluronidase, phosphomonoesterase acid ester, α-D-glucosidase, lysophospholipase, α-galactosidase, α-acetylamino-deoxsiglucosidase, and arylamidase. The venom will cause localized or systemic inflammation, an anticoagulant effect that may be fatal. CASE REPORT: Herewith, a survival case report suffered from DIC with multi-organ failure following severe anaphylaxis shock post a hundred or massive Hornet sting. CONCLUSION: We have reported a case of anaphylactic shock after a massive hornet sting with DIC that presented symptoms of shock, AKI, ALI, and multi-site bleeding. Although the mortality rate for similar cases is quite high, the outcome will be better with comprehensive and adequate treatment.

Allergenome profiling of Vespa orientalis venom by serum IgE in patients with anaphylactic reaction to this hornet sting

BackgroundHymenoptera stings are one of the most common causes of anaphylaxis. Vespa orientalis (red hornet) is a common and very aggressive hymenopteran endemic in central and southern areas of Iran. Allergy testing and venom immunotherapies are carried out with venom components which are expensive, have limited commercial availability, and often lack specificity. Although proteomic analysis of hymenopteran venom has been shown to be a powerful technique to identify allergens, data on the protein components of V. orientalis venom are lacking. AimThis study was designed to characterize the allergenome profile (proteome of allergenic proteins) of this local hornet venom. MethodsVenom was extracted from V. orientalis worker venom sacs. The venom constituents were separated by two-dimensional gel electrophoresis (2DE). Protein components were blotted and probed with serum from 10 allergic patients by immunoblotting. Reactive spots were isolated and characterized by liquid chromatography with tandem mass spectrometry. ResultsA total of 195 protein spots were detected on the 2DE gels. Fifteen distinct venom proteins showed reactivity to IgE in patients’ sera. Four major allergens in order of allergenicity in patients were identified as hyaluronidase, arginine kinase, phospholipase A1 (PLA1) and PLA1 magnifin. ConclusionsBroadening our knowledge of V. orientalis venom constituents can contribute to improvements in diagnostic and immunotherapeutic techniques, both of which are dependent on the major allergens in venom extract. This information is also potentially helpful to develop medical uses of major allergens in this venom to improve the diagnostic specificity and the efficacy of immunotherapy.

A rat model of acute kidney injury caused by multiple subcutaneous injections of Asian giant hornet (Vespa mandarina Smith) venom

A model of acute kidney injury (AKI) caused by multiple subcutaneous injections of Asian giant hornet (Vespa mandarina Smith) venom was developed in male Wistar rats. The rats were injected subcutaneously at multiple sites in the dorsal region with a total venom dose of 5 mg/kg. Blood samples were obtained 8, 24 and 48 h after venom injection for the quantification of various biochemical parameters and assessment of renal function. Wasp venom caused significant increases in all biochemical parameters (aspartate aminotransferase, creatine kinase, free hemoglobin, lactate dehydrogenase, myoglobin, and plasma creatinine) within 8 h of venom administration, as well as marked alterations in renal function (a decrease in glomerular filtration rate leading to oliguria). The biochemical parameters showed varying degrees of recovery but remained elevated to varying degrees after 48 h, whereas the glomerular filtration rate showed no recovery during this period. The histopathological alterations consisted primarily of acute tubular necrosis, with tubular epithelial cell sloughing and loss of tubule brush border. This profile of biochemical and functional alterations was similar to that seen in human envenomations by this species, suggesting that this animal model may be useful for understanding the pathophysiology of AKI caused by this wasp venom.

The Diagnostic Importance of Recombinant Allergen IgE Testing in Patients with Hymenoptera Venom Allergy: Comparison of Two Methods

Adults with systemic anaphylactic reactions (SAR) to insect sting show often multiple-positivity of serum-specific IgE (sIgE) to Hymenoptera venoms. Unnecessary long-lasting venom-specific immunotherapies (VIT) in false-positive patients increase the risk of recurrent SAR. This report aims to analyze the diagnostic importance of recombinant allergen IgE testing in patients with SAR to Hymenoptera sting. In 82 patients we measured sIgE to honeybee venom (HBV), wasp venom (WV) and hornet venom (HV) extracts, recombinant phospholipase A2 from HBV (sIgE-rApi m1), recombinant antigen 5 from WV (sIgE-rVes v5), and cross-reactive carbohydrate determinants-CCD-bromelain by ImmunoCAP.We analyzed the correlation of ImmunoCAP and Immunoblot for HBV and WV extracts, rApi m1, and rVes v5 in 39/82 patients. According to the history of the culprit insect, we compared sensitivity and specificity between the two methods. The severity of the SAR does not depend on the sIgE level to venom extracts and recombinant allergens. Fifty-one percent of the patients had a multiple-positivity to HBV/WV or HBV/WV/HV extracts. Severe SAR and CCD-sIgE were more frequent in multiple-positive than single-positive patients. CCD-sIgE were more frequent in HBV allergic patients than WV and HVallergic patients. There was a significant correlation between levels of sIgE to venom extracts and recombinant allergens measured by ImmunoCAP and Immunoblot. ImmunoCAP has higher sensitivity and specificity than Immunoblot for diagnosis of SAR to Hymenoptera venoms. IgE testing to recombinant CCD-free allergens is necessary for the adequate selection of long-lasting VIT, especially in patients with multiple sensitivities to venom extracts.

Functional characterization, antimicrobial effects, and potential antibacterial mechanisms of new mastoparan peptides from hornet venom (Vespa ducalis, Vespa mandarinia, and Vespa affinis)

Antibiotic-resistant bacteria are a major threat to global public health, and there is an urgent need to find effective, antimicrobial treatments that can be well tolerated by humans. Hornet venom is known to have antimicrobial properties, and contains peptides with similarity to known antimicrobial eptides (AMPs), mastoparans. We identified multiple new AMPs from the venom glands of Vespa ducalis (U-VVTX-Vm1a, U-VVTX-Vm1b, and U-VVTX-Vm1c), Vespa mandarinia (U-VVTX-Vm1d), and Vespa affinis (U-VVTX-Vm1e). All of these AMPs have highly similar sequences and are related to the toxic peptide, mastoparan. Our newly identified AMPs have α-helical structures, are amphiphilic, and have antimicrobial properties. Both U-VVTX-Vm1b and U-VVTX-Vm1e killed bacteria, Staphylococcus aureus ATCC25923 and Escherichia coli ATCC25922, at the concentrations of 16 μg/mL and 32 μg/mL, respectively. None of the five AMPs exhibited strong toxicity as measured via their hemolytic activity on red blood cells. U-VVTX-Vm1b was able to increase the permeability of E. coli ATCC25922 and degrade its genomic DNA. These results are promising, demonstrate the value of investigating hornet venom as an antimicrobial treatment, and add to the growing arsenal of such naturally derived treatments.

Hornet venom and remission of psoriasis.

Hornet venom and remission of psoriasis.

HYMENOPTERA TOXINS: BIOLOGICAL ACTIVITY, PHARMACEUTICAL AND THERAPEUTIC USES

The present review article explains the salient features of hornet venom toxins, their physiological, biological and pharmacological effect on animals and man. Hornets sting very fast and inflict venom, which is more dangerous than those of bees. Hornet venom contains both proteinaceous and non-proteinaceous peptides i.e. scapin, adolapin, mellitin, mastoparans and enzymes, mainly phospholipase and hyaluronidase, which show multiple biological effects i.e. cytolytic, hemotoxic, neuro-inhibitor, anticancer, anti-parasitic, immune hypersensitive, inflammatory, antimicrobial and anti-insect activities. Hornet stings are more painful to humans than typical wasp stings because hornet venom contains a large amount (5%) of acetylcholine. Hornet toxin components interact with receptors, ion channels and gated channels and affect the permeability functions of cells. Heavy envenomation shows quick pathophysiological lethal effects in man and pet. This article emphasizes the use of various hornet venom components for the production of disease-modifying anti-rheumatic and analgesic, anticancer drugs and insecticides. Hornet venom allergens could be used to prepare the rational design of component-resolved diagnosis of allergy and venom immunotherapy of inflicting patients.

Identifying the toxins in hornet (Vespa basalis) venom that induce rat pain responses

The black-bellied hornet Vespa basalis is responsible for the large quantity of accidents and severe wasp envenomation in China. This study aims to identify the rat pain responses induced by experimental V. basalis sting and related-components in the venom. It was observed that unilateral intraplantar injection of crude V. basalis venom could induce several kinds of pain related behaviors in a dose-dependent manner including spontaneous pain, unilateral thermal and unilateral mechanical hypersensitivity at different time courses. Fourteen main fractions were separated from the crude venom of V. basalis using high performance liquid chromatography, among them, five components (1, 3, 4, 9 and 12) could absolutely mimic the crude venom-induced pain behaviors. According to the molecular mass and N-terminal sequence, the component 3 and 4 were identified as Mastoparan B and HP-1 respectively, the component 9 was speculated as a novel variant of HP-1/2. In addition, the other two sub-components (1-1 and 1–2) purified from component 1 cannot be determined. The results offered the key information about six active polypeptides from V. basalis contributing to pain responses, which might provide a basis for exploring mechanisms of wasp sting injury.

Development of an LC-MS multivariate nontargeted methodology for differential analysis of the peptide profile of Asian hornet venom (Vespa velutina nigrithorax): application to the investigation of the impact of collection period variation.

Insect venom is a highly complex mixture of bioactive compounds, containing proteins, peptides, and small molecules. Environmental factors can alter the venom composition and lead to intraspecific variation in its bioactivity properties. The investigation of discriminating compounds caused by variation impacts can be a key to manage sampling and explore the bioactive compounds. The present study reports the development of a peptidomic methodology based on UHPLC-ESI-QTOF-HRMS analysis followed by a nontargeted multivariate analysis to reveal the profile variance of Vespa velutina venom collected in different conditions. The reliability of the approach was enhanced by optimizing certain XCMS data processing parameters and determining the sample peak threshold to eliminate the interfering features. This approach demonstrated a good repeatability and a criterion coefficient of variation (CV) > 30% was set for deleting nonrepeatable features from the matrix. The methodology was then applied to investigate the impact of collection period variation. PCA and PLS-DA models were used and validated by cross-validation and permutation tests. A slight discrimination was found between winter and summer hornet venom in two successive years with 10 common discriminating compounds. Graphical abstract.

Asian hornet Vespa velutina nigrithorax venom: Evaluation and identification of the bioactive compound responsible for human keratinocyte protection against oxidative stress

The present study aimed to explore the potential antioxidant molecules of the Asian hornet venom (Vespa velutina nigrithorax) responsible for radical scavenging activity and human keratinocyte protection against oxidative stress. We developed a first technical platform that combined a DPPH radical scavenging chemical assay and cytotoxicity and ROS (reactive oxygen species) production in HaCaT keratinocyte cells exposed to UVB to evaluate the antioxidant property of V. velutina venom. We further employed Thin Layer Chromatography (TLC) combined with the DPPH assay as a targeted separation approach to isolate the antioxidant compounds responsible for the free radical scavenging property of V. velutina venom. In parallel, the latter was fractionated by a HPLC-DAD non-targeted separation approach. From this experiment, nine fractions were generated which were again evaluated separately for their antioxidant properties using DPPH assays. Results showed that only one fraction exhibited significant antioxidant activity in which serotonin was identified as the major compound by a UHPLC-ESI-QTOF HRMS/MS approach. We finally demonstrated, using purified serotonin molecule that this bioactive structure is mostly responsible for the free radical scavenging property of the crude venom as evidenced by DPPH and ROS assays in HaCaT cells exposed to UVB.

Purification and molecular characterization of phospholipase, antigen 5 and hyaluronidases from the venom of the Asian hornet (Vespa velutina).

The aim of this study was to purify potential allergenic components of Vespa velutina venom, the yellow legged Asian Hornet, and perform a preliminary characterization of the purified proteins. Starting from the whole venom of V.velutina, several chromatographic steps allowed to purify the phospholipase (named Vesp v 1), as well as the antigen 5 (Vesp v 5, the only allergenic component described as such so far). The two hyaluronidase isoforms found (Vesp v 2A and Vesp v 2B) cannot be separated from each other, but they are partially purified and characterized. Purity of the isolated proteins in shown by SDSPAGE, as well as by the results of the N-terminal sequencing. This characterization and nLC-MS/MS data provide most of the sequence for Vesp v 1 and Vesp v 5 (72 and 84% coverage, respectively), confirming that the whole sequences of the isolated natural components match with the data available in public transcriptomic databases. It is of particular interest that Vesp v 1 is a glycosylated phospholipase, a fact that had only described so far for the corresponding allergen components of Dolichovespula maculata and Solenopsis invicta. The availability of the complete sequences of Vespa velutina components permits comparison with homologous sequences from other Hymenoptera. These data demonstrate the higher similarity among the species of the genera Vespa and Vespula, in comparison to Polistes species, as it is especially observed with the hyaluronidases isoforms: the isoform Vesp v 2A only exists in the former genera, and not in Polistes; in addition, the most abundant isoform (Vesp v 2B) exhibits 93% sequence identity with the Ves v 2 isoform of Vespula vulgaris. Finally, the isolated components might be useful for improving the diagnosis of patients that could be allergic to stings of this invasive Asian hornet, as it has been the case of an improved diagnosis and treatment of other Hymenoptera-sensitized patients.

Triple IgE-positivity to hornet, wasp and bee venom in the patient with anaphylaxis: Diagnostic and therapeutic approach

Introduction. Triple-positivity (TP) or double-positivity (DP) for serum-specific immunoglobulin E (sIgE) antibodies against hornet venom (HV), wasp venom (WV) and/or honeybee venom (BV) causes significant problem in a selection of appropriate venom immunotherapy. However, DP/TP can be caused by cross-reactions resulting either from partial sequence identity of protein allergens in the venoms, or may be related to cross-reacting carbohydrate determinants (CCDs). Case report. A 60-year-old man was stung by a wasp and two days later by hornet. In both cases, within 15 minutes he developed hypotension and generalized urticaria and he was successfully treated with epinephrine, corticosteroids and fluids. After eight weeks, the examination revealed the negative skin prick test for all three venoms, but the sIgE-determination (ELISA, Biopharm) showed triple sensitization to native BV (0.55 IU/mL), WV (3.35 IU/mL) and HV (0.37 IU/mL). He was receiving the venom immunotherapy with venom mixtures for one year. In order to distinguish true multiple sensitization from cross-reactivity, the molecular-allergy testing by ImmunCAP with the CCD-free recombinant major allergens was performed. A high sensitization to Antigen 5-rVes v5 of WV (31.4 kU/L) was demonstrated while sIgE to phospholipase A2-rApi m1 of BV (0.15 kU/L) was negative; sIgE to CCDMUXF3- bromelain (0.75 kU/L) explained the sIgE-positivity for native BV. After these findings, a venom immunotherapy only with WV was initiated. Conclusion. In our patient, triple-IgE-positivity to native venoms detected by the ELISA was caused by cross-reactivity to CCDs. We recommend the molecular-allergy testing with the nonglycosylated recombinant allergens before starting the venom immunotherapy in patients with multiple-sIgE-positivity to native Hymenoptera venoms.

Antimicrobial effects of wasp (Vespa orientalis) venom

Background and objective The discovery of novel naturally occurring antimicrobial agents is one of the most promising approaches for overcoming the growing threat of antibiotic-resistant pathogens. Venomous animals from different ecological niches and taxonomic groups have recently gained attention in the search for new antimicrobials to treat infectious diseases. Therefore, the main aim of the present study was to investigate the antimicrobial activity of Orient hornet venom. Materials and methods Different concentrations of wasp venom were tested for their antimicrobial effect against two gram-negative bacteria (Salmonella typhimurium, Escherichia coli), two gram-positive bacteria (Bacillus cereus, Staphylococcus aureus), and one yeast like fungi (Candida albicans). The antimicrobial activity was analyzed using the well diffusion method, where zones of inhibition were used as indicators of antimicrobial activity. Results and conclusion The venom exhibited notable antimicrobial activity against all tested pathogens. Gram-positive bacterial strains were found to be more sensitive than both gram-negative bacterial strains and fungal strain. The highest inhibition zones were determined to be 24.3±1.9, 29.3±1.5, 17.3±1.8, 14.0±1.7, and 15.7±1.5 mm for S. aureus, B. cereus, S. typhimurium, E. coli, and C. albicans, respectively. The corresponding minimum inhibitory concentration values were determined to be 0.32, 0.16, 0.625, 1.25, and 0.625 mg/ml, respectively. These results offer insights into the antimicrobial potency of wasp venom and provide a basis for further pharmacological research.

Venom-derived peptide Mastoparan-1 eradicates planktonic and biofilm-embedded methicillin-resistant Staphylococcus aureus isolates

During the past decade, cationic antimicrobial peptides (CAPs) have gained particular interest among researchers, since they often display broad-spectrum antimicrobial activity and low possibility of resistance emergence. This study aimed to investigate in vitro effectiveness of Mastoparan-1 (MP-1), a tetradecapeptide CAP from hornet venom, against methicillin-resistant Staphylococcus aureus (MRSA) isolates. MP-1 had a high propensity to form alpha-helix based on structural predictions. MP-1 was found to possess strong antimicrobial activities and weak cytotoxic effects. Multiple treatments of MRSA with MP-1 at sub-lethal dose did not induce resistance. At 4 × minimum bactericidal concentration (MBC), MP-1 eradicated bacteria within 60 min, whereas vancomycin was unable to eradicate MRSA even after 480 min of exposure, highlighting rapid bactericidal kinetics of MP-1. Treatment of bacteria with 2 × MBC of MP-1 caused a time-dependent increase in orange/red fluorescence intensity. Compared with vancomycin, MP-1 significantly reduced biofilm formation and diminished both biofilm biomass and viability of biofilm-embedded bacteria in a concentration-dependent manner. Taken together, the current data reveal not only that MP-1 is a potent bactericidal and antibiofilm agent, but also that it is less likely to invoke antimicrobial resistance, reinforcing further studies concerning the therapeutic applications of MP-1.

Evaluation of the bioactivity of a mastoparan peptide from wasp venom and of its analogues designed through targeted engineering.

Mastoparan is a typical cationic and amphipathic tetradecapeptide found in wasp venom and exhibits potent biological activities. Yet, compared with other insect-derived peptides, such as melittin from the bee venom, this family have been underrated. Herein, we evaluated the biological activities of mastoparan-C (MP-C), which was identified from the venom of the European Hornet (Vespa crabro), and rationally designed two analogues (a skeleton-based cyclization by two cysteine residues and an N-terminal extension via tat-linked) for enhancing the stability of the biological activity and membrane permeability, respectively. Three peptides possessed broadly efficacious inhibiting capacities towards common pathogens, resistant strains, as well as microbial biofilm. Although, cyclized MP-C showed longer half-life time than the parent peptide, the lower potency of antimicrobial activity and higher degree of haemolysis were observed. The tat-linked MP-C exhibited more potent anticancer activity than the parent peptide, but it also loses the specificity. The study revealed that MP-C is good candidate for developing antimicrobial agents and the targeted-design could improve the stability and transmembrane delivery, but more investigation would be needed to adjust the side effects brought from the design.