Hyaluronidase from the venom of the social wasp Polybia paulista (Hymenoptera, Vespidae): Cloning, structural modeling, purification, and immunological analysis

Proteomic analyses of venom from a Spider Hawk, Pepsis decorata

Background

The composition of the venom from solitary wasps is poorly known, although these animals are considered sources of bioactive substances. Until the present moment, there is only one proteomic characterization of the venom of wasps of the family Pompilidae and this is the first proteomic characterization for the genus Pepsis.

Methods

To elucidate the components of Pepsis decorata venom, the present work sought to identify proteins using four different experimental conditions, namely: (A) crude venom; (B) reduced and alkylated venom; (C) trypsin-digested reduced and alkylated venom, and; (D) chymotrypsin-digested reduced and alkylated venom. Furthermore, three different mass spectrometers were used (Ion Trap-Time of Flight, Quadrupole-Time of Flight, and Linear Triple Quadruple).

Results

Proteomics analysis revealed the existence of different enzymes related to the insect's physiology in the venom composition. Besides toxins, angiotensin-converting enzyme (ACE), hyaluronidase, and Kunitz-type inhibitors were also identified.

Conclusion

The data showed that the venom of Pepsis decorata is mostly composed of proteins involved in the metabolism of arthropods, as occurs in parasitic wasps, although some classical toxins were recorded, and among them, for the first time, ACE was found in the venom of solitary wasps. This integrative approach expanded the range of compounds identified in protein analyses, proving to be efficient in the proteomic characterization of little-known species. It is our understanding that the current work will provide a solid base for future studies dealing with other Hymenoptera venoms.

Characterization of the Composition and Biological Activity of the Venom from Vespa bicolor Fabricius, a Wasp from South China

We analyzed, for the first time, the major components and biological properties of the venom of Vespa bicolor, a wasp from South China. Using HPLC and SDS-PAGE, combined with LC–MS/MS, MALDI-TOF-MS, and NMR data to analyze V. bicolor venom (VBV), we found that VBV contains three proteins (hyaluronidase A, phospholipase A1 (two isoforms), and antigen 5 protein) with allergenic activity, two unreported proteins (proteins 5 and 6), and two active substances with large quantities (mastoparan-like peptide 12a (Vb-MLP 12a), and 5-hydroxytryptamine (5-HT)). In addition, the antimicrobial activity of VBV was determined, and results showed that it had a significant effect against anaerobic bacteria. The minimum inhibitory concentration and minimum bactericidal concentration for Propionibacterium acnes were 12.5 µg/mL. Unsurprisingly, VBV had strong antioxidant activity because of the abundance of 5-HT. Contrary to other Vespa venom, VBV showed significant anti-inflammatory activity, even at low concentrations (1 µg/mL), and we found that Vb-MLP 12a showed pro-inflammatory activity by promoting the proliferation of RAW 264.7 cells. Cytotoxicity studies showed that VBV had similar antiproliferative effects against all tested tumor cell lines (HepG2, Hela, MCF-7, A549, and SASJ-1), with HepG2 being the most susceptible. Overall, this study on VBV has high clinical importance and promotes the development of Vespa bicolor resources.

Shedding Lights on Crude Venom from Solitary Foraging Predatory Ant Ectatomma opaciventre: Initial Toxinological Investigation

Some species of primitive predatory ants, despite living in a colony, exercise their hunting collection strategy individually; their venom is painful, paralyzing, digestive, and lethal for their prey, yet the toxins responsible for these effects are poorly known. Ectatomma opaciventre is a previously unrecorded solitary hunting ant from the Brazilian Cerrado. To overcome this hindrance, the present study performed the in vitro enzymatic, biochemical, and biological activities of E. opaciventre to better understand the properties of this venom. Its venom showed several proteins with masses ranging from 1-116 kDa, highlighting the complexity of this venom. Compounds with high enzymatic activity were described, elucidating different enzyme classes present in the venom, with the presence of the first L-amino acid oxidase in Hymenoptera venoms being reported. Its crude venom contributes to a state of blood incoagulability, acting on primary hemostasis, inhibiting collagen-induced platelet aggregation, and operating on the fibrinolysis of loose red clots. Furthermore, the E. opaciventre venom preferentially induced cytotoxic effects on lung cancer cell lines and three different species of Leishmania. These data shed a comprehensive portrait of enzymatic components, biochemical and biological effects in vitro, opening perspectives for bio-pharmacological application of E. opaciventre venom molecules.

Biological and Inflammatory Effects of Antigen 5 from Polybia paulista (Hymenoptera, Vespidae) Venom in Mouse Intraperitoneal Macrophages

The social wasp Polybia paulista (Hymenoptera, Vespidae) is highly aggressive, being responsible for many medical occurrences. One of the most allergenic components of this venom is Antigen 5 (Poly p 5). The possible modulation of the in vitro immune response induced by antigen 5 from P. paulista venom, expressed recombinantly (rPoly p 5), on BALB/c mice peritoneal macrophages, activated or not with LPS, was assessed. Here, we analyzed cell viability changes, expression of the phosphorylated form of p65 NF-κB subunit, nitric oxide (NO), proinflammatory cytokines production, and co-stimulatory molecules (CD80, CD86). The results suggest that rPoly p 5 does not affect NO production nor the expression of co-stimulatory molecules in mouse peritoneal macrophages. On the other hand, rPoly p 5 induced an increase in IL-1β production in non-activated macrophages and a reduction in the production of TNF-α and MCP-1 cytokines in activated macrophages. rPoly p 5 decreased the in vitro production of the phosphorylated p65 NF-κB subunit in non-activated macrophages. These findings suggest an essential role of this allergen in the polarization of functional M2 macrophage phenotypes, when analyzed in previously activated macrophages. Further investigations, mainly in in vivo studies, should be conducted to elucidate Polybia paulista Ag5 biological role in the macrophage functional profile modulation.

Hyaluronidases and hyaluronate lyases: From humans to bacteriophages

Hyaluronan is a non-sulfated negatively-charged linear polymer distributed in most parts of the human body, where it is located around cells in the extracellular matrix of connective tissues and plays an essential role in the organization of tissue architecture. Moreover, hyaluronan is involved in many biological processes and used in many clinical, cosmetic, pharmaceutic, and biotechnological applications worldwide. As interest in hyaluronan applications increases, so does interest in hyaluronidases and hyaluronate lyases, as these enzymes play a major part in hyaluronan degradation. Many hyaluronidases and hyaluronate lyases produced by eukaryotic cells, bacteria, and bacteriophages have so far been described and annotated, and their ability to cleave hyaluronan has been experimentally proven. These enzymes belong to several carbohydrate-active enzyme families, share very low sequence identity, and differ in their cleaving mechanisms and in their structural and functional properties. This review presents a summary of annotated and characterized hyaluronidases and hyaluronate lyases isolated from different sources belonging to distinct protein families, with a main focus on the binding and catalytic residues of the discussed enzymes in the context of their biochemical properties. In addition, the application potential of individual groups of hyaluronidases and hyaluronate lyases is evaluated.

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.

Functional Profile of Antigen Specific CD4+ T Cells in the Immune Response to Phospholipase A1 Allergen from Polybia paulista Venom

Insect venom can cause systemic allergic reactions, including anaphylaxis. Improvements in diagnosis and venom immunotherapy (VIT) are based on a better understanding of an immunological response triggered by venom allergens. Previously, we demonstrated that the recombinant phospholipase A1 (rPoly p 1) from Polybia paulista wasp venom induces specific IgE and IgG antibodies in sensitized mice, which recognized the native allergen. Here, we addressed the T cell immune response of rPoly p 1-sensitized BALB/c mice. Cultures of splenocytes were stimulated with Polybia paulista venom extract and the proliferation of CD8⁺ and CD4⁺ T cells and the frequency of T regulatory cells (Tregs) populations were assessed by flow cytometry. Cytokines were quantified in cell culture supernatants in ELISA assays. The in vitro stimulation of T cells from sensitized mice induces a significant proliferation of CD4⁺ T cells, but not of CD8⁺ T cells. The cytokine pattern showed a high concentration of IFN-γ and IL-6, and no significant differences to IL-4, IL-1β and TGF-β1 production. In addition, the rPoly p 1 group showed a pronounced expansion of CD4⁺CD25⁺FoxP3⁺ and CD4⁺CD25^-FoxP3⁺ Tregs. rPoly p 1 sensitization induces a Th1/Treg profile in CD4⁺ T cell subset, suggesting its potential use in wasp venom immunotherapy.

An Integrated Proteomic and Transcriptomic Analysis Reveals the Venom Complexity of the Bullet Ant Paraponera clavata

A critical hurdle in ant venom proteomic investigations is the lack of databases to comprehensively and specifically identify the sequence and function of venom proteins and peptides. To resolve this, we used venom gland transcriptomics to generate a sequence database that was used to assign the tandem mass spectrometry (MS) fragmentation spectra of venom peptides and proteins to specific transcripts. This was performed alongside a shotgun liquid chromatography-mass spectrometry (LC-MS/MS) analysis of the venom to confirm that these assigned transcripts were expressed as proteins. Through the combined transcriptomic and proteomic investigation of Paraponera clavata venom, we identified four times the number of proteins previously identified using 2D-PAGE alone. In addition to this, by mining the transcriptomic data, we identified several novel peptide sequences for future pharmacological investigations, some of which conform with inhibitor cysteine knot motifs. These types of peptides have the potential to be developed into pharmaceutical or bioinsecticide peptides.

Heterologous expression and mutagenesis of recombinant Vespa affinis hyaluronidase protein (rVesA2)

Background

Crude venom of the banded tiger waspVespa affinis contains a variety of enzymes including hyaluronidases, commonly known as spreading factors.

Methods

The cDNA cloning, sequence analysis and structural modelling of V. affinis venom hyaluronidase (VesA2) were herein described. Moreover, heterologous expression and mutagenesis of rVesA2 were performed.

Results

V. affinis venom hyaluronidase full sequence is composed of 331 amino acids, with four predicted N-glycosylation sites. It was classified into the glycoside hydrolase family 56. The homology modelling exhibited a central core (α/β)₇ composed of Asp107 and Glu109, acting as the catalytic residues. The recombinant protein was successfully expressed in E. coli with hyaluronidase activity. A recombinant mutant type with the double point mutation, Asp107Asn and Glu109Gln, completely lost this activity. The hyaluronidase from crude venom exhibited activity from pH 2 to 7. The recombinant wild type showed its maximal activity at pH 2 but decreased rapidly to nearly zero at pH 3 and was completely lost at pH 4.

Conclusion

The recombinant wild-type protein showed its maximal activity at pH 2, more acidic pH than that found in the crude venom. The glycosylation was predicted to be responsible for the pH optimum and thermal stability of the enzymes activity.

Polybia occidentalis and Polybia fastidiosa venom: a cytogenotoxic approach of effects on human and vegetal cells

The venoms of wasps are a complex mixture of biologically active compounds, such as low molecular mass compounds, peptides, and proteins. The aim of the study was to evaluate the action of wasp venoms, Polybia occidentalis and Polybia fastidiosa, on the DNA of human leukocytes and on the cell cycle and genetic material of the plant model Lactuca sativa L. (lettuce). The cultured leukocytes were treated with the venoms and then evaluated by the comet assay. On another assay, seeds were exposed to a venom solution; the emitted roots were collected and the occurrence of cell cycle alterations (CCAs) and DNA fragmentation were evaluated by agarose gel electrophoresis and TUNEL assay. The results demonstrated that the venom of both wasps induces several CCAs and reduces the mitotic index (MI) on treated cells. They induced damage on human leukocytes DNA. High frequencies of fragments were observed in cells exposed to P. occidentalis venom, while those exposed to P. fastidiosa showed a high frequency of non-oriented chromosome. Both venoms induced the occurrence of various condensed nuclei (CN). This alteration is an excellent cytological mark to cell death (CD). Additionally, CD was evidenced by positive signals in TUNEL assay, by DNA fragmentation in agarose gel electrophoresis with vegetal cells, and by DNA fragmentation of the human leukocytes evaluated. Furthermore, human leukocytes exposed to the venom of P. fastidiosa had high rate of damage. The data demonstrate that both vegetal and human cells are adequate to evaluate the genotoxicity induced by venoms.

Revisiting Polybia paulista wasp venom using shotgun proteomics - Insights into the N-linked glycosylated venom proteins

The partial proteome of Polybia paulista wasp venom was previously reported elsewhere using a gel-dependent approach and resulted in the identification of a limited number of venom toxins. Here, we reinvestigated the P. paulista venom using a gel-free shotgun proteomic approach; the highly dynamic range of this approach facilitated the detection and identification of 1673 proteins, of which 23 venom proteins presented N-linked glycosylation as a posttranslational modification. Three different molecular forms of PLA1 were identified as allergenic proteins, and two of these forms were modified by N-linked glycosylation. This study reveals an extensive repertoire of hitherto undescribed proteins that were classified into the following six different functional groups: (i) typical venom proteins; (ii) proteins related to the folding/conformation and PTMs of toxins; (iii) proteins that protect toxins from oxidative stress; (iv) proteins involved in chemical communication; (v) housekeeping proteins; and (vi) uncharacterized proteins. It was possible to identify venom toxin-like proteins that are commonly reported in other animal venoms, including arthropods such as spiders and scorpions. Thus, the findings reported here may contribute to improving our understanding of the composition of P. paulista venom, its envenoming mechanism and the pathologies experienced by the victim after the wasp stinging accident. BIOLOGICAL SIGNIFICANCE: The present study significantly expanded the number of proteins identified in P. paulista venom, contributing to improvements in our understanding of the envenoming mechanism produced by sting accidents caused by this wasp. For example, novel wasp venom neurotoxins have been identified, but no studies have assessed the presence of this type of toxin in social wasp venoms. In addition, 23 N-linked glycosylated venom proteins were identified in the P. paulista venom proteome, and some of these proteins might be relevant allergens that are immunoreactive to human IgE.

Heterologous Expression, Purification and Immunoreactivity of the Antigen 5 from Polybia paulista Wasp Venom

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.

Isolation and characterization of Conohyal-P1, a hyaluronidase from the injected venom of Conus purpurascens

Hyaluronidases are ubiquitous enzymes commonly found in venom and their main function is to degrade hyaluran, which is the major glycosaminoglycan of the extracellular matrix in animal tissues. Here we describe the purification and characterization of a 60kDa hyaluronidase found in the injected venom from Conus purpurascens, Conohyal-P1. Using a combined strategy based on transcriptomic and proteomic analysis, we determined the Conohyal-P1 sequence. Conohyal-P1 has conserved consensus catalytic and positioning domain residues characteristic of hyaluronidases and a C-terminus EGF-like domain. Additionally, the enzyme is expressed as a mixture of glycosylated isoforms at five asparagine sites. The activity of the native Conohyal-P1 was assess MS-based methods and confirmed by classical turbidimetric methods. The MS-based assay is particularly sensitive and provides the first detailed analysis of a venom hyaluronidase activity monitored with this method. The discovery of new hyaluronidases and the development of techniques to evaluate their performance can advance several therapeutic procedures, as these enzymes are widely used for enhanced drug delivery applications.

BIOLOGICAL SIGNIFICANCE

Cone snail venom is a remarkable source of therapeutically important molecules, as is the case of conotoxins, which have undergone extensive clinical trials for several applications. In addition to the conotoxins, a large array of proteins have been reported in the venom of several species of cone snails, including enzymes that were found in dissected and injected Conus venom. Here we describe the isolation and characterization of the hyaluronidase Conohyal-P1 from the injected venom of C. purpurascens. We employed a combined transcriptomic and proteomic analysis to obtain the full sequence of this hyaluronidase. The activity of Conohyal-P1 was assessed by a mass spectrometry-based method, which provide the first detailed venom hyaluronidase activity analysis monitored by mass spectrometry allowing the visualization of the substrate degradation by the enzyme.

Wasp venomic: Unravelling the toxins arsenal of Polybia paulista venom and its potential pharmaceutical applications

Polybia paulista (Hymenoptera: Vespidae) is a neotropical social wasp from southeast Brazil. As most social Hymenoptera, venom from P. paulista comprises a complex mixture of bioactive toxins ranging from low molecular weight compounds to peptides and proteins. Several efforts have been made to elucidate the molecular composition of the P. paulista venom. Data derived from proteomic, peptidomic and allergomic analyses has enhanced our understanding of the whole envenoming process caused by the insect sting. The combined use of bioinformatics, -omics- and molecular biology tools have allowed the identification, characterization, in vitro synthesis and recombinant expression of several wasp venom toxins. Some of these P. paulista - derived bioactive compounds have been evaluated for the rational design of antivenoms and the improvement of allergy specific diagnosis and immunotherapy. Molecular characterization of crude venom extract has enabled the description and isolation of novel toxins with potential biotechnological applications. Here, we review the different approaches that have been used to unravel the venom composition of P. paulista. We also describe the main groups of P. paulista - venom toxins currently identified and analyze their potential in the development of component-resolved diagnosis of allergy, and in the rational design of antivenoms and novel bioactive drugs.

Variation in Venoms of Polybia Paulista Von Ihering and Polybia Occidentalis Olivier (Hymenoptera: Vespidae), Assessed by the FTIR-PAS Technique

Wasps are able to synthesize toxic compounds known as venoms, which form a part of a mechanism to overcome prey and also to defend their colonies. Study of the compounds that constitute these substances is essential in order to understand how this defense mechanism evolved, since there is evidence that the venoms can vary both intra- and interspecifically. Some studies have used liquid and gas chromatography as a reliable technique to analyze these compounds. However, the use of Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) to analyze the variations in venom's chemical profile has been proposed recently. This study evaluated whether the FTIR-PAS technique is effective for assessing the role of environmental factors on intra- and interspecific differences in the venom of the wasps Polybia paulista Von Ihering and Polybia occidentalis Olivier by FTIR-PAS. The colonies were collected in three municipalities of Mato Grosso do Sul, Brazil, in different types of environments. The results showed that the venoms of P. paulista and P. occidentalis differed significantly in profile. In addition, the intraspecific differences in the venom's chemical profile of P. paulista are related to the type of environment where they nested, regardless of the geographical distance between the nests. The FTIR-PAS technique proved to be reliable and effective to evaluate the variations in the venom's chemical profile in social wasps.

Molecular cloning, expression and IgE-immunoreactivity of phospholipase A1, a major allergen from Polybia paulista (Hymenoptera: Vespidae) venom

Polybia paulista (Hymenoptera: Vespidae) is a clinically relevant social wasp that frequently causes stinging accidents in southeast Brazil. To date, diagnosis and specific immunotherapy (SIT) of allergy are based on the use of crude venom extracts. Production of recombinant forms of major allergens from P. paulista venom will improve diagnosis and SIT of allergic patients by reducing the incidence of cross-reactivity and non-specific sensitization. Here, we describe the molecular cloning, heterologous expression, purification and IgE-mediated immunodetection of phospholipase A1 (Poly p 1), a major allergen from P. paulista venom. The cDNA of Poly p 1 was extracted from venom glands and then cloned, and further expression of the recombinant allergen (rPoly p 1) was achieved in Escherichia coli BL21 (DE3) cells. Purification of rPoly p 1 was performed using immobilized Ni²⁺ metal affinity chromatography. Also, a single-step chromatographic method allowed the purification of native Poly p 1 (nPoly p 1) from the wasp's venom glands. We used western blotting to evaluate IgE-reactivity of the sera from 10 P. paulista venom-allergic patients to rPoly p 1 and nPoly p 1. High levels of insoluble rPoly p 1 were obtained during heterologous expression. After solubilization of inclusion bodies and purification of the recombinant protein, a unique band of ∼34 kDa was detected in SDS-PAGE analysis. Allergen-specific IgE (sIgE) from allergic patients' sera recognized rPoly p 1, nPoly p 1 and crude venom extract to a similar extent. Our results showed that rPoly p 1 could be used for development of component-resolved diagnosis (CRD) and molecular-defined SIT of P. paulista venom allergy.

Cloning, structural modelling and characterization of VesT2s, a wasp venom hyaluronidase (HAase) from Vespa tropica

Background

Wasp venom is a complex mixture containing proteins, enzymes and small molecules, including some of the most dangerous allergens. The greater banded wasp (Vespa tropica) is well-known for its lethal venom, whose one of the major components is a hyaluronidase (HAase). It is believed that the high protein proportion and activity of this enzyme is responsible for the venom potency.

Methods

In the present study, cDNA cloning, sequencing and 3D-structure of Vespa tropica venom HAase were described. Anti-native HAase antibody was used for neutralization assay.

Results

Two isoforms, VesT2a and VesT2b, were classified as members of the glycosidase hydrolase 56 family with high similarity (42–97 %) to the allergen venom HAase. VesT2a gene contained 1486 nucleotide residues encoding 357 amino acids whereas the VesT2b isoform consisted of 1411 residues encoding 356 amino acids. The mature VesT2a and VesT2b are similar in mass and pI after prediction. They are 39119.73 Da/pI 8.91 and 39571.5 Da/pI 9.38, respectively. Two catalytic residues in VesT2a, Asp107 and Glu109 were substituted in VesT2b by Asn, thus impeding enzymatic activity. The 3D-structure of the VesT2s isoform consisted of a central core (α/β)₇ barrel and two disulfide bridges. The five putative glycosylation sites (Asn79, Asn99, Asn127, Asn187 and Asn325) of VesT2a and the three glycosylation sites (Asn1, Asn66 and Asn81) in VesT2b were predicted. An allergenic property significantly depends on the number of putative N-glycosylation sites. The anti-native HAase serum specifically recognized to venom HAase was able to neutralize toxicity of V. tropica venom. The ratio of venom antiserum was 1:12.

Conclusions

The wasp venom allergy is known to cause life-threatening and fatal IgE-mediated anaphylactic reactions in allergic individuals. Structural analysis was a helpful tool for prediction of allergenic properties including their cross reactivity among the vespid HAase.

Comparative proteomic analysis of two wasps venom, Vespa tropica and Vespa affinis

Vespid venom is composed of many bioactive compounds. The venom of the banded tiger wasp (Vespa affinis, or VA) and the great banded wasp (Vespa tropica, or VT)-which are locally found in the northeastern part of Thailand and are well known for their life-threatening venom potency-were comparatively studied in terms of potency, composition and biological activity. Clinical studies that included word-of-mouth information shared by traditional healers in local areas noted that the venom of VT is more potent than that of VA. Our previous study showed that the venom of VA is lower in potency (PD50 = 12.5 μg/g body weight) than that of VT (PD50 = 3 μg/g body weight). Analysis with the PAGE technique showed that these two venoms showed similar patterns of active proteins. Most protein spots were basic proteins at an isoelectric point (pI) ranging from 5 to 10, with molecular weights between 27 and 50 kDa. These spots were identified as hyaluronidase, phospholipase, antigen 5, dipeptidyl peptidase and albumin-like protein. The proportion of hyaluronidase was 2.5 times higher in VT than in VA. VT also showed higher hyaluronidase, phospholipase and dipeptidyl peptidase activities, suggesting that these components made VT venom more potent than VA venom.

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.

Arthropod venom Hyaluronidases: biochemical properties and potential applications in medicine and biotechnology

Hyaluronidases are enzymes that mainly degrade hyaluronan, the major glycosaminoglycan of the interstitial matrix. They are involved in several pathological and physiological activities including fertilization, wound healing, embryogenesis, angiogenesis, diffusion of toxins and drugs, metastasis, pneumonia, sepsis, bacteremia, meningitis, inflammation and allergy, among others. Hyaluronidases are widely distributed in nature and the enzymes from mammalian spermatozoa, lysosomes and animal venoms belong to the subclass EC 3.2.1.35. To date, only five three-dimensional structures for arthropod venom hyaluronidases (Apis mellifera and Vespula vulgaris) were determined. Additionally, there are four molecular models for hyaluronidases from Mesobuthus martensii, Polybia paulista and Tityus serrulatus venoms. These enzymes are employed as adjuvants to increase the absorption and dispersion of other drugs and have been used in various off-label clinical conditions to reduce tissue edema. Moreover, a PEGylated form of a recombinant human hyaluronidase is currently under clinical trials for the treatment of metastatic pancreatic cancer. This review focuses on the arthropod venom hyaluronidases and provides an overview of their biochemical properties, role in the envenoming, structure/activity relationship, and potential medical and biotechnological applications.

Facing Hymenoptera Venom Allergy: From Natural to Recombinant Allergens

Along with food and drug allergic reactions, a Hymenoptera insect Sting (Apoidea, Vespidae, Formicidae) is one of the most common causes of anaphylaxis worldwide. Diagnoses of Hymenoptera venom allergy (HVA) and specific immunotherapy (SIT) have been based on the use of crude venom extracts. However, the incidence of cross-reactivity and low levels of sensibility during diagnosis, as well as the occurrence of nonspecific sensitization and undesired side effects during SIT, encourage the search for novel allergenic materials. Recombinant allergens are an interesting approach to improve allergy diagnosis and SIT because they circumvent major problems associated with the use of crude venom. Production of recombinant allergens depends on the profound molecular characterization of the natural counterpart by combining some “omics” approaches with high-throughput screening techniques and the selection of an appropriate system for heterologous expression. To date, several clinically relevant allergens and novel venom toxins have been identified, cloned and characterized, enabling a better understanding of the whole allergenic and envenoming processes. Here, we review recent findings on identification, molecular characterization and recombinant expression of Hymenoptera venom allergens and on the evaluation of these heterologous proteins as valuable tools for tackling remaining pitfalls on HVA diagnosis and immunotherapy.

De Novo sequencing and transcriptome analysis for Tetramorium bicarinatum: a comprehensive venom gland transcriptome analysis from an ant species

BACKGROUND

Arthropod venoms are invaluable sources of bioactive substances with biotechnological application. The limited availability of some venoms, such as those from ants, has restricted the knowledge about the composition and the potential that these biomolecules could represent. In order to provide a global insight on the transcripts expressed in the venom gland of the Brazilian ant species Tetramorium bicarinatum and to unveil the potential of its products, high-throughput approach using Illumina technology has been applied to analyze the genes expressed in active venom glands of this ant species.

RESULTS

A total of 212,371,758 pairs of quality-filtered, 100-base-pair Illumina reads were obtained. The de novo assemblies yielded 36,042 contigs for which 27,873 have at least one predicted ORF among which 59.77% produce significant hits in the available databases. The investigation of the reads mapping toxin class revealed a high diversification with the major part consistent with the classical hymenopteran venom protein signature represented by venom allergen (33.3%), followed by a diverse toxin-expression profile including several distinct isoforms of phospholipase A1 and A2, venom serine protease, hyaluronidase, protease inhibitor and secapin. Moreover, our results revealed for the first time the presence of toxin-like peptides that have been previously identified from unrelated venomous animals such as waprin-like (snakes) and agatoxins (spiders and conus).The non-toxin transcripts were mainly represented by contigs involved in protein folding and translation, consistent with the protein-secretory function of the venom gland tissue. Finally, about 40% of the generated contigs have no hits in the databases with 25% of the predicted peptides bearing signal peptide emphasizing the potential of the investigation of these sequences as source of new molecules. Among these contigs, six putative novel peptides that show homologies with previously identified antimicrobial peptides were identified.

CONCLUSIONS

To the best of our knowledge, this work reports the first large-scale analysis of genes transcribed by the venomous gland of the ant species T. bicarinatum and helps with the identification of Hymenoptera toxin arsenal. In addition, results from this study demonstrate that de novo transcriptome assembly allows useful venom gene expression analysis in a species lacking a genome sequence database.

Cloning and molecular characterization of scorpion Buthus martensi venom hyaluronidases: a novel full-length and diversiform noncoding isoforms

Hyaluronidase is a common component of scorpion venom and has been considered as "spreading factor" that promotes a fast penetration of the venom in the anaphylactic reaction. In the current study, a novel full-length of hyaluronidase BmHYI and three noncoding isoforms of BmHYII, BmHYIII and BmHYIV were cloned by using a combined strategy based on peptide sequencing and Rapid Amplification of cDNA Ends (RACE). BmHYI has 410 amino acid residues containing the catalytic, positional and five potential N-glycosylation sites. The deduced protein sequence of BmHYI shares significant identity with venom hyaluronidases from bees and snakes. The phylogenetic analysis showed early divergence and independent evolution of BmHYI from other hyaluronidases. An extraordinarily high level of sequence similarity was detected among four sequences. But, BmHYII, BmHYIII and BmHYIV were short of stop-codon in the open reading frame and poly(A) signal in the 3' end.

Molecular, immunological, and biological characterization of Tityus serrulatus venom hyaluronidase: new insights into its role in envenomation

Background

Scorpionism is a public health problem in Brazil, and Tityus serrulatus (Ts) is primarily responsible for severe accidents. The main toxic components of Ts venom are low-molecular-weight neurotoxins; however, the venom also contains poorly characterized high-molecular-weight enzymes. Hyaluronidase is one such enzyme that has been poorly characterized.

Methods and principal findings

We examined clones from a cDNA library of the Ts venom gland and described two novel isoforms of hyaluronidase, TsHyal-1 and TsHyal-2. The isoforms are 83% identical, and alignment of their predicted amino acid sequences with other hyaluronidases showed conserved residues between evolutionarily distant organisms. We performed gel filtration followed by reversed-phase chromatography to purify native hyaluronidase from Ts venom. Purified native Ts hyaluronidase was used to produce anti-hyaluronidase serum in rabbits. As little as 0.94 µl of anti-hyaluronidase serum neutralized 1 LD₅₀ (13.2 µg) of Ts venom hyaluronidase activity in vitro. In vivo neutralization assays showed that 121.6 µl of anti-hyaluronidase serum inhibited mouse death 100%, whereas 60.8 µl and 15.2 µl of serum delayed mouse death. Inhibition of death was also achieved by using the hyaluronidase pharmacological inhibitor aristolochic acid. Addition of native Ts hyaluronidase (0.418 µg) to pre-neutralized Ts venom (13.2 µg venom+0.94 µl anti-hyaluronidase serum) reversed mouse survival. We used the SPOT method to map TsHyal-1 and TsHyal-2 epitopes. More peptides were recognized by anti-hyaluronidase serum in TsHyal-1 than in TsHyal-2. Epitopes common to both isoforms included active site residues.

Conclusions

Hyaluronidase inhibition and immunoneutralization reduced the toxic effects of Ts venom. Our results have implications in scorpionism therapy and challenge the notion that only neurotoxins are important to the envenoming process.

In Brazil, accidents with scorpion stings have been a serious public health problem, and Tityus serrulatus (Ts) is primarily responsible for severe accidents. Therefore, efforts have been made to understand the characteristics of the molecules present in scorpion venoms. These venoms are complex mixtures, in which neurotoxins are the main toxic components. Ts venom also contains enzymes, such as hyaluronidase, that have not been well characterized. In this study, we described for the first time two sequences of Ts hyaluronidase isoforms: TsHyal-1 and TsHyal-2. We purified native hyaluronidase from Ts venom and produced anti-hyaluronidase serum in rabbits. This serum neutralized hyaluronidase activity present in Ts venom. In vivo neutralization assays showed that anti-hyaluronidase serum inhibited and delayed mouse death after injection of a lethal dose (50% lethal dose, LD₅₀) of Ts venom. This work confirms the influence of hyaluronidase in Ts venom lethality and paves the way for the development of new strategies for scorpionism therapy.