Molecular cloning of the precursor polypeptide of mastoparan B and its putative processing enzyme, dipeptidyl peptidase IV, from the black-bellied hornet, Vespa basalis

Structural Similarities, in Relation with the Cross-Reactivity, of Hymenoptera Allergenic Dipeptidyl Peptidases IV-An Overall Comparison Including a New Dipeptidyl Peptidase IV Sequence from Vespa velutina

(1) Background: Dipeptidyl Peptidases IV (DPPIVs), present in many organisms, are minor components in the venoms of Hymenoptera, where they have been identified as cross-reactive allergenic molecules. Considering that the structure of homologous DPPIVs is well characterized, we aimed to explain which regions have higher similarity among these proteins and present a comparison among them, including a new Vespa velutina DPPIV sequence. Moreover, two cases of sensitization to DPPIVs in wasp- and honeybee-sensitized patients are presented. (2) Methods: Proteomic analyses have been performed on the venom of the Asian hornet Vespa velutina to demonstrate the sequence of its DPPIV (allergen named Vesp v 3, with sequence accession number P0DRB8, and with the proteomic data available via ProteomeXchange with the identifier PXD046030). A comparison performed through their alignments and analysis of the three-dimensional structure showed a region with higher similarity among Hymenoptera DPPIVs. Additionally, ImmunoCAP™ determinations (including specific inhibition experiments), as well as IgE immunoblotting, are performed to demonstrate the allergenicity of Api m 5 and Ves v 3. (3) Results and Conclusions: The data presented demonstrate that the similarities among Hymenoptera DPPIVs are most likely localized at the C-terminal region of these enzymes. In addition, a higher similarity of the Vespa/Vespula DPPIVs is shown. The clinical cases analyzed demonstrated the allergenicity of Api m 5 and Ves v 3 in the sera of the allergic patients, as well as the presence of this minor component in the preparations used in venom immunotherapy.

Insects as an alternative protein source for poultry nutrition: a review

This review summarizes the most relevant scientific literature related to the use of insects as alternative protein sources in poultry diets. The black soldier fly, the housefly, the beetle, mealworms, silkworms, earthworms, crickets, and grasshoppers are in the spotlight because they have been identified as an important future source of sustainable animal proteins for poultry feeding. Insect meals meet poultry requirements in terms of nutritional value, essential amino acid composition, nutrient digestibility, and feed acceptance. Furthermore, they are enriched with antimicrobial peptides and bioactive molecules that can improve global health. Results from poultry studies suggest equivalent or enhanced growth performances and quality of end-products as compared to fish meal and soybean meal. To outline this body of knowledge, this article states established threads of research about the nutrient profiles and the digestibility of insect meals, their subsequent effects on the growth and laying performances of poultry as well as the quality of meat, carcass, and eggs. To fully exploit insect-derived products, the effects of insect bioactive molecules (antimicrobial peptides, fatty acids, and polysaccharides) were addressed. Furthermore, as edible insects are likely to take a meaningful position in the feed and food chain, the safety of their derived products needs to be ensured. Some insights into the current knowledge on the prevalence of pathogens and contaminants in edible insects were highlighted. Finally, the effect of insect farming and processing treatment on the nutritive value of insect larvae was discussed. Our overview reveals that using insects can potentially solve problems related to reliance on other food sources, without altering the growth performances and the quality of meat and eggs.

Molecular Characterization and Functional Analysis of the Dipeptidyl Peptidase IV from Venom of the Ectoparasitoid Scleroderma guani

Dipeptidyl peptidase IV (DPPIV) is a proline-specific serine peptidase that remains poorly investigated in terms of venom composition. Here, we describe the molecular characteristics and possible functions of DPPIV as a major venom component of the ant-like bethylid ectoparasitoid, Scleroderma guani, named SgVnDPPIV. The SgVnDPPIV gene was cloned, which encodes a protein with the conserved catalytic triads and substrate binding sites of mammalian DPPIV. This venom gene is highly expressed in the venom apparatus. Recombinant SgVnDPPIV, produced in Sf9 cells using the baculovirus expression system, has high enzymatic activity, which can be efficiently inhibited by vildagliptin and sitagliptin. Functional analysis revealed that SgVnDPPIV affects genes related to detoxification, lipid synthesis and metabolism, response to stimuli, and ion exchange in pupae of Tenebrio molitor, an envenomated host of S. guani. The present work contributes towards understanding the role of venom DPPIV involved in the interaction between parasitoid wasp and its host.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Antimicrobial Peptide Mastoparan-AF Kills Multi-Antibiotic Resistant Escherichia coli O157:H7 via Multiple Membrane Disruption Patterns and Likely by Adopting 3-11 Amphipathic Helices to Favor Membrane Interaction

We investigated the antimicrobial activity and membrane disruption modes of the antimicrobial peptide mastoparan-AF against hemolytic Escherichia coli O157:H7. Based on the physicochemical properties, mastoparan-AF may potentially adopt a 3-11 amphipathic helix-type structure, with five to seven nonpolar or hydrophobic amino acid residues forming the hydrophobic face. E. coli O157:H7 and two diarrheagenic E. coli veterinary clinical isolates, which are highly resistant to multiple antibiotics, are sensitive to mastoparan-AF, with minimum inhibitory and bactericidal concentrations (MIC and MBC) ranging from 16 to 32 μg mL^-1 for E. coli O157:H7 and four to eight μg mL^-1 for the latter two isolates. Mastoparan-AF treatment, which correlates proportionally with membrane permeabilization of the bacteria, may lead to abnormal dents, large perforations or full opening at apical ends (hollow tubes), vesicle budding, and membrane corrugation and invagination forming irregular pits or pores on E. coli O157:H7 surface. In addition, mRNAs of prepromastoparan-AF and prepromastoparan-B share a 5'-poly(A) leader sequence at the 5'-UTR known for the advantage in cap-independent translation. This is the first report about the 3-11 amphipathic helix structure of mastoparans to facilitate membrane interaction. Mastoparan-AF could potentially be employed to combat multiple antibiotic-resistant hemolytic E. coli O157:H7 and other pathogenic E. coli.

Mastoparans: A Group of Multifunctional α-Helical Peptides With Promising Therapeutic Properties

Biologically active peptides have been attracting increasing attention, whether to improve the understanding of their mechanisms of action or in the search for new therapeutic drugs. Wasp venoms have been explored as a remarkable source for these molecules. In this review, the main findings on the group of wasp linear cationic α-helical peptides called mastoparans were discussed. These compounds have a wide variety of biological effects, including mast cell degranulation, activation of protein G, phospholipase A₂, C, and D activation, serotonin and insulin release, and antimicrobial, hemolytic, and anticancer activities, which could lead to the development of new therapeutic agents.

Bioactive Peptides and Proteins from Wasp Venoms

Wasps, members of the order Hymenoptera, use their venom for predation and defense. Accordingly, their venoms contain various constituents acting on the circulatory, immune and nervous systems. Wasp venom possesses many allergens, enzymes, bioactive peptides, amino acids, biogenic amines, and volatile matters. In particular, some peptides show potent antimicrobial, anti-inflammatory, antitumor, and anticoagulant activity. Additionally, proteinous components from wasp venoms can cause tissue damage or allergic reactions in organisms. These bioactive peptides and proteins involved in wasp predation and defense may be potential sources of lead pharmaceutically active molecules. In this review, we focus on the advances in bioactive peptides and protein from the venom of wasps and their biological effects, as well as the allergic reactions and immunotherapy induced by the wasp venom.

Dipeptidyl peptidase IV of the Vespa velutina nigrithorax venom is recognized as a relevant allergen

BACKGROUND

Vespa velutina nigrithorax (VVN), commonly known as "the Asian yellow-legged wasp," has been one of the most significant invasive species in western Europe since 2010. Currently, VVN has become the most prevalent cause of Hymenoptera anaphylaxis in north and northwestern Spain. For this reason, it is crucial to diagnose anaphylaxis cases in the acute moment for carrying out the best available treatment as soon as possible.

OBJECTIVE

To achieve a complete understanding of the venom allergen composition that will help to develop efficient diagnostics and immunotherapy treatments based on this venom.

METHODS

In this work, autochthonous VVN venom was obtained and characterized by SDS-PAGE, isoelectric focusing, followed by a mass spectrometry analysis. In addition, the allergenic sensitization profile of patients diagnosed with allergy to VVN in the Allergology Service of Navarra University Hospital between the years 2017-2020 was studied by immunoblotting and specific IgE (ImmunoCAP).

RESULTS

Two new allergens (dipeptidyl peptidase IV and serin protease) were identified in the autochthonous VVN venom, and their identity was confirmed by LC-MS analysis. The study by ImmunoCAP using sera from 12 patients who suffered a systemic reaction after a VVN sting revealed group 5 and group 1 as predominant allergens (92% and 34%, respectively). Furthermore, the immunoblotting assay showed a recognition of the dipeptidyl peptidase IV (50%) by the sera of these patients.

CONCLUSION

A serin protease and the dipeptidyl peptidase IV are components of the VVN venom, and this last one is an allergen recognized in the studied population.

Diversity of compounds in Vespa spp. venom and the epidemiology of its sting: a global appraisal

Poisonous animals imply a risk to human life, because their venom is a complex mixture of low molecular weight components, peptides and proteins. Hornets use the venom for self-defence, to repel intruders and to capture prey, but they can cause poisoning and allergic reactions to people. In particular, they seem to be a health problem in the countries where they are native due to their sting, which in the most severe cases can lead to severe or fatal systemic anaphylaxis. But this situation is being an emerging problem for new countries and continents because hornet incursions are increasing in the global change scenario, such as in Europe and America. Furthermore, 55 detailed cases of hornet sting were found in 27 papers during the current review where 36.4% died due to, mainly, a multi-organ failure, where renal failure and liver dysfunction were the most common complications. Moreover, the great taxonomic, ecological diversity, geographical distribution and the wide spectrum of pathophysiological symptoms of hornets have been the focus of new research. Considering this, the present systematic review summarizes the current knowledge about the components of Vespa venom and the epidemiology of its sting to serve as reference for the new research focused on the development of techniques for diagnosis, new drugs and treatments of its sting.

Shedding Light on the Venom Proteomes of the Allergy-Relevant Hymenoptera Polistes dominula (European Paper Wasp) and Vespula spp. (Yellow Jacket)

Allergic reactions to stings of Hymenoptera species can have serious or even fatal consequences. If the identification of the culprit insect is possible, venom-specific immunotherapy effectively cures Hymenoptera venom allergies. Although component-resolved diagnostics has strongly evolved in recent years, the differentiation between allergies to closely related species such as Polistes dominula and Vespula spp. is still challenging. In order to generate the basis for new diagnostic and therapeutic strategies, this study aims at resolving the venom proteomes (venomes) of these species. The venoms of P. dominula and Vespula spp. (V. germanica, V. vulgaris) were analyzed by liquid chromatography-mass spectrometry. Resulting proteins were characterized regarding their function, localization and biochemical properties. The analyses yielded 157 proteins in Vespula spp. and 100 in P. dominula venom; 48 proteins, including annotated allergens, were found in both samples. In addition to a variety of venom trace molecules, new allergen candidates such as icarapin-like protein and phospholipase A2 were identified. This study elucidates the venomes of closely related allergy-eliciting Hymenoptera species. The data indicates that relying on marker allergens to differentiate between P. dominula and Vespula spp. venom allergy is probably insufficient and that strategies using cross-reactive major allergens could be more promising.

Protein Discovery: Combined Transcriptomic and Proteomic Analyses of Venom from the Endoparasitoid Cotesia chilonis (Hymenoptera: Braconidae)

Many species of endoparasitoid wasps provide biological control services in agroecosystems. Although there is a great deal of information on the ecology and physiology of host/parasitoid interactions, relatively little is known about the protein composition of venom and how specific venom proteins influence physiological systems within host insects. This is a crucial gap in our knowledge because venom proteins act in modulating host physiology in ways that favor parasitoid development. Here, we identified 37 possible venom proteins from the polydnavirus-carrying endoparasitoid Cotesia chilonis by combining transcriptomic and proteomic analyses. The most abundant proteins were hydrolases, such as proteases, peptidases, esterases, glycosyl hydrolase, and endonucleases. Some components are classical parasitoid venom proteins with known functions, including extracellular superoxide dismutase 3, serine protease inhibitor and calreticulin. The venom contains novel proteins, not recorded from any other parasitoid species, including tolloid-like proteins, chitooligosaccharidolytic β-N-acetylglucosaminidase, FK506-binding protein 14, corticotropin-releasing factor-binding protein and vascular endothelial growth factor receptor 2. These new data generate hypotheses and provide a platform for functional analysis of venom components.

Deciphering the main venom components of the ectoparasitic ant-like bethylid wasp, Scleroderma guani

Similar to venom found in most venomous animals, parasitoid venoms contain a complex cocktail of proteins with potential agrichemical and pharmaceutical use. Even though parasitoids are one of the largest group of venomous animals, little is known about their venom composition. Recent few studies revealed high variated venom composition existing not only in different species but also between closely related strains, impling that increasing information on the venom proteins from more greater diversity of species of different taxa is key to comprehensively uncover the complete picture of parasitoid venom. Here, we explored the major protein components of the venom of ectoparasitic ant-like bethylid wasp, Scleroderma guani by an integrative transcriptomic-proteomic approach. Illumina deep sequencing of venom apparatus cDNA produced 49,873 transcripts. By mapping the peptide spectral data derived from venom reservoir against these transcripts, mass spectrometry analysis revealed ten main venom proteins, including serine proteinase, metalloprotease, dipeptidyl peptidase IV, esterase, antithrombin-III, acid phosphatase, neural/ectodermal development factor IMP-L2 like protein, venom allergen 3, and unknown protein. Interestingly, one serine proteinase was firstly identified with rarely high molecular weight about 200 kDa in parasitoid venom. The occurrence of abundant acid phosphatase, antithrombin-III and venom allergen 3 demonstrated that S. guani venom composition is similar to that of social wasp venoms. All identified venom genes showed abundantly biased expression in venom apparatus, indicating their virulent functions involved in parasitization. This study shed light on the more better understanding of parasitoid venom evolution across species and will facilitate the further elucidation of function and toxicity of these venom proteins.

Differential Properties of Venom Peptides and Proteins in Solitary vs. Social Hunting Wasps

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.

Global Transcriptome Analysis of the Tentacle of the Jellyfish Cyanea capillata Using Deep Sequencing and Expressed Sequence Tags: Insight into the Toxin- and Degenerative Disease-Related Transcripts

BACKGROUND

Jellyfish contain diverse toxins and other bioactive components. However, large-scale identification of novel toxins and bioactive components from jellyfish has been hampered by the low efficiency of traditional isolation and purification methods.

RESULTS

We performed de novo transcriptome sequencing of the tentacle tissue of the jellyfish Cyanea capillata. A total of 51,304,108 reads were obtained and assembled into 50,536 unigenes. Of these, 21,357 unigenes had homologues in public databases, but the remaining unigenes had no significant matches due to the limited sequence information available and species-specific novel sequences. Functional annotation of the unigenes also revealed general gene expression profile characteristics in the tentacle of C. capillata. A primary goal of this study was to identify putative toxin transcripts. As expected, we screened many transcripts encoding proteins similar to several well-known toxin families including phospholipases, metalloproteases, serine proteases and serine protease inhibitors. In addition, some transcripts also resembled molecules with potential toxic activities, including cnidarian CfTX-like toxins with hemolytic activity, plancitoxin-1, venom toxin-like peptide-6, histamine-releasing factor, neprilysin, dipeptidyl peptidase 4, vascular endothelial growth factor A, angiotensin-converting enzyme-like and endothelin-converting enzyme 1-like proteins. Most of these molecules have not been previously reported in jellyfish. Interestingly, we also characterized a number of transcripts with similarities to proteins relevant to several degenerative diseases, including Huntington's, Alzheimer's and Parkinson's diseases. This is the first description of degenerative disease-associated genes in jellyfish.

CONCLUSION

We obtained a well-categorized and annotated transcriptome of C. capillata tentacle that will be an important and valuable resource for further understanding of jellyfish at the molecular level and information on the underlying molecular mechanisms of jellyfish stinging. The findings of this study may also be used in comparative studies of gene expression profiling among different jellyfish species.

Rhodamine B-conjugated encrypted vipericidin nonapeptide is a potent toxin to zebrafish and associated with in vitro cytotoxicity

BACKGROUND

Animal venoms contain a diverse array of proteins and enzymes that are toxic toward various physiological systems. However, there are also some practical medicinal uses for these toxins including use as anti-bacterial and anti-tumor agents.

METHODS

In this study, we identified a nine-residue cryptic oligopeptide, KRFKKFFKK (EVP50) that is repeatedly encoded in tandem within vipericidin sequences.

RESULTS

EVP50 displayed in vivo potent lethal toxicity to zebrafish larvae (LD50=6 μM) when the peptide's N-terminus was chemically conjugated to rhodamine B (RhoB). In vitro, RhoB-conjugated EVP50 (RhoB-EVP50) exhibited a concentration-dependent cytotoxic effect toward MCF-7 and MDA-MB-231 breast cancer cells. In MCF-7 cells, the RhoB-EVP50 nonapeptide accumulated inside the cells within minutes. In the cytoplasm, the RhoB-EVP50 induced extracellular calcium influx and intracellular calcium release. Membrane budding was also observed after incubation with micromolar concentrations of the fluorescent EVP50 conjugate.

CONCLUSIONS

The conjugate's interference with calcium homeostasis, its intracellular accumulation and its induced membrane dysfunction (budding and vacuolization) seem to act in concert to disrupt the cell circuitry. Contrastively, unconjugated EVP50 peptide did not display neither toxic nor cytotoxic activities in our in vivo and in vitro models.

GENERAL SIGNIFICANCE

The synergic mechanism of toxicity was restricted to the structurally modified encrypted vipericidin nonapeptide.

Efficacy of parenteral administration of bee venom in experimental arthritis in the rat: a comparison with methotrexate

The use of bee venom (BV) to treat inflammation and pain in arthritis has become increasingly common. This study aimed to compare the effects of BV and methotrexate (MTX), the most used disease-modifying anti-rheumatic drug, in arthritic rats. Edema, erythema, cyanosis, hyperalgesia, reduction of the body mass gain, high circulating tumor necrosis factor alpha (TNF-α) and anti-type II collagen antibodies (AACII), and altered activity of basic (APB) and neutral (APN) aminopeptidases and dipeptidyl peptidase IV (DPPIV) are present in arthritic rats. MTX and/or BV do not affect AACII in healthy or arthritic individuals, but restores TNF-α to normal levels in arthritic rats. BV restores body mass gain to normal levels and MTX ameliorates body mass gain. BV contains DPPIV. BV restores APN in synovial fluid (SF) and in soluble fraction (S) from synovial tissue (ST), and DPPIV in solubilized membrane-bound fraction (M) from peripheral blood mononuclear cells (PBMCs). MTX restores APN of SF, as well as ameliorates APB of S-PBMCs, APN of S-ST and DPPIV of M-PBMCs. The combination therapy does not overcome the effects of BV or MTX alone on the peptidase activities. Edema is ameliorated by MTX or BV alone. MTX, but not BV, is effective in reducing hyperalgesia. Data show that anti-arthritic effects of BV at non-acupoints are not negligible when compared with MTX.

Venom gland extract is not required for successful parasitism in the polydnavirus-associated endoparasitoid Hyposoter didymator (Hym. Ichneumonidae) despite the presence of numerous novel and conserved venom proteins

The venom gland is a conserved organ in Hymenoptera that shows adaptations associated with life-style diversification. Few studies have investigated venom components and function in the highly diverse parasitic wasps and all suggest that the venom regulates host physiology. We explored the venom of the endoparasitoid Hyposoter didymator (Campopleginae), a species with an associated polydnavirus produced in the ovarian tissue. We investigated the effects of the H. didymator venom on two physiological traits of the host Spodoptera frugiperda (Noctuidae): encapsulation response and growth rate. We found that H. didymator venom had no significant effect on host cellular immunity or development, suggesting that it does not contribute to parasitism success. The host physiology seemed to be modified essentially by the ovarian fluid containing the symbiotic polydnaviruses. Proteomic analyses indicated that the H. didymator venom gland produces a large variety of proteins, consistent with the classical hymenopteran venom protein signature, including: reprolysin-like, dipeptidyl peptidase IV, hyaluronidase, arginine kinase or allergen proteins. The venom extracts also contained novel proteins, encoded by venom genes conserved in Campopleginae ichneumonids, and proteins with similarities to active molecules identified in other parasitoid species, such as calreticulin, reprolysin, superoxide dismutase and serpin. However, some of these proteins appear to be produced only in small amounts or to not be secreted. Possibly, in Campopleginae carrying polydnaviruses, the host-modifying activities of venom became redundant following the acquisition of polydnaviruses by the lineage.

Overview on the recent study of antimicrobial peptides: origins, functions, relative mechanisms and application

Antimicrobial peptides (AMPs), which are produced by several species including insects, other animals, micro-organisms and synthesis, are a critical component of the natural defense system. With the growing problem of pathogenic organisms resistant to conventional antibiotics, especially with the emergence of NDM-1, there is increased interest in the pharmacological application of AMPs. They can protect against a broad array of infectious agents, such as bacteria, fungi, parasite, virus and cancer cells. AMPs have a very good future in the application in pharmaceuticals industry and food additive. This review focuses on the AMPs from different origins in these recent years, and discusses their various functions and relative mechanisms of action. It will provide some detailed files for clinical research of pharmaceuticals industry and food additive in application.

Structural and biological characterization of mastoparans in the venom of Vespa species in Taiwan

Mastoparans, a family of small peptides, are isolated from the wasp venom. In this study, six mastoparans were identified in the venom of six Vespa species in Taiwan. The precursors of these mastoparans are composed of N-terminal signal sequence, prosequence, mature mastoparan, and appendix glycine at C-terminus. These mature mastoparans all have characteristic features of linear cationic peptides rich in hydrophobic and basic amino acids without disulfide bond. Therefore, these peptides could be predicted to adopt an amphipathic α-helical secondary structure. In fact, the CD (circular dichroism) spectra of these peptides show a high content α-helical conformation in the presence of 8 mM SDS or 40% 2,2,2-trifluoroethanol (TFE). All mastoparans exhibit mast cell degranulation activity, antimicrobial activity against both Gram-positive and -negative bacteria tested, various degree of hemolytic activity on chicken, human, and sheep erythrocytes as well as membrane permeabilization on Escherichia coli BL21. Our results also show that the hemolytic activity of mastoparans is correlated to mean hydrophobicity and mean hydrophobic moment.

Venom peptides from solitary hunting wasps induce feeding disorder in lepidopteran larvae

The cell lytic activity and toxicity against lepidopteran larvae of 13 venom peptides (4 OdVPs and 9 EpVPs) from two solitary hunting wasps, Orancistrocerus drewseni and Eumenes pomiformis, were examined with mastoparan as a reference peptide. Of the 13 peptides, 7 were predicted to have α-helical structures that exhibit the typical character of amphipathic α-helical antimicrobial peptides. The remaining peptides exhibited coil structures; among these, EpVP5 possesses two Cys residues that form an internal disulfide bridge. All the helical peptides including mastoparan showed antimicrobial and insect cell lytic activities, whereas only two of them were hemolytic against human erythrocytes. The helical peptides induced a feeding disorder when injected into the vicinity of the head and thorax of Spodoptera exigua larvae, perhaps because their non-specific neurotoxic or myotoxic action induced cell lysis. At low concentrations, however, these helical peptides increased cell permeability without inducing cell lysis. These findings suggest that the helical venom peptides may function as non-specific neurotoxins or myotoxins and venom-spreading factors at low concentrations, as well as preservatives for long-term storage of the prey via antimicrobial, particularly antifungal, activities.

A transcriptomic analysis of gene expression in the venom gland of the snake Bothrops alternatus (urutu)

Background

The genus Bothrops is widespread throughout Central and South America and is the principal cause of snakebite in these regions. Transcriptomic and proteomic studies have examined the venom composition of several species in this genus, but many others remain to be studied. In this work, we used a transcriptomic approach to examine the venom gland genes of Bothrops alternatus, a clinically important species found in southeastern and southern Brazil, Uruguay, northern Argentina and eastern Paraguay.

Results

A cDNA library of 5,350 expressed sequence tags (ESTs) was produced and assembled into 838 contigs and 4512 singletons. BLAST searches of relevant databases showed 30% hits and 70% no-hits, with toxin-related transcripts accounting for 23% and 78% of the total transcripts and hits, respectively. Gene ontology analysis identified non-toxin genes related to general metabolism, transcription and translation, processing and sorting, (polypeptide) degradation, structural functions and cell regulation. The major groups of toxin transcripts identified were metalloproteinases (81%), bradykinin-potentiating peptides/C-type natriuretic peptides (8.8%), phospholipases A₂ (5.6%), serine proteinases (1.9%) and C-type lectins (1.5%). Metalloproteinases were almost exclusively type PIII proteins, with few type PII and no type PI proteins. Phospholipases A₂ were essentially acidic; no basic PLA₂ were detected. Minor toxin transcripts were related to L-amino acid oxidase, cysteine-rich secretory proteins, dipeptidylpeptidase IV, hyaluronidase, three-finger toxins and ohanin. Two non-toxic proteins, thioredoxin and double-specificity phosphatase Dusp6, showed high sequence identity to similar proteins from other snakes. In addition to the above features, single-nucleotide polymorphisms, microsatellites, transposable elements and inverted repeats that could contribute to toxin diversity were observed.

Conclusions

Bothrops alternatus venom gland contains the major toxin classes described for other Bothrops venoms based on trancriptomic and proteomic studies. The predominance of type PIII metalloproteinases agrees with the well-known hemorrhagic activity of this venom, whereas the lower content of serine proteases and C-type lectins could contribute to less marked coagulopathy following envenoming by this species. The lack of basic PLA₂ agrees with the lower myotoxicity of this venom compared to other Bothrops species with these toxins. Together, these results contribute to our understanding of the physiopathology of envenoming by this species.

Docking study of the precursor peptide of mastoparan onto its putative processing enzyme, dipeptidyl peptidase IV: a revisit to molecular ticketing

Stepwise-cleavage process of promastoparans to reach maturity was investigated theoretically by combining ab initio folding and unbounded docking. The comparison between the structures of the promastoparans both before and after docking were examined along with the hydrogen bonding interaction pattern between the dipetidyl peptidase IV (DPPIV) and promastoparans to reveal how the endpoint of this stepwise cleavage is recognized among these promastoparans with highly resemble amino acid sequences. The current approach of folding and docking study provides structural insight on the stepwise cleavage process.

Antimicrobial peptides from the venoms of Vespa bicolor Fabricius

Hornets possess highly toxic venoms, which are rich in toxins, enzymes and biologically active peptides. Many bioactive substances have been identified from wasp venoms. Vespa mastoparan (MP-VBs) and Vespa chemotatic peptide presenting antimicrobial action (VESP-VBs) were purified and characterized from the venom of the wasp, Vespa bicolor Fabricius. The precursors encoding VESP-VBs and MP-VBs were cloned from the cDNA library of the venomous glands. Analyzed by FAB-MS, the amino acid sequence and molecular mass for VESP-VB1 were FMPIIGRLMSGSL and 1420.6, for MP-VB1 were INMKASAAVAKKLL and 1456.5, respectively. The primary structures of these peptides are homologous to those of chemotactic peptides and mastoparans isolated from other vespid venoms. These peptides showed strong antimicrobial activities against bacteria and fungi and induced mast cell degranulation, but displayed almost no hemolytic activity towards human blood red cells.