Novel neuroprotective peptides in the venom of the solitary scoliid wasp Scolia decorata ventralis

Background Solitary wasp venoms may be a rich source of neuroactive substances, since their venoms are used for paralyzing preys. We have been exploring bioactive constituents of solitary wasp venoms and, in this study, the component profile of the venom from a solitary scoliid wasp, Scolia decorata ventralis, was investigated through a comprehensive analysis using LC-MS. Two peptides were synthesized, and their neuroprotective properties were evaluated. Methods A reverse-phase HPLC connected to ESI-MS was used for LC-MS analyses. Online mass fingerprinting was performed from TIC, and data-dependent tandem mass spectrometry gave the MS/MS spectra. The sequences of two major peptide components were determined by MALDI-TOF/TOF MS analysis, confirmed by solid phase synthesis. Using the synthetic peptides, biological activities were assessed. Cell integrity tests and neuroprotection analyzes using H2O2 as an oxidative stress inducer were performed for both peptides. Results Online mass fingerprinting revealed that the venom contains 123 components, and the MS/MS analysis resulted in 33 full sequences of peptide components. The two main peptides, α-scoliidine (DYVTVKGFSPLR) and β-scoliidine (DYVTVKGFSPLRKA), present homology with the bradykinin C-terminal. Despite this, both peptides did not behave as substrates or inhibitors of ACE, indicating that they do not interact with this metallopeptidase. In further studies, β-scoliidine, but not α -scoliidine, showed protective effects against oxidative stress-induced neurotoxicity in PC12 cells through integrity and metabolism cell assays. Interestingly, β-scoliidine has the extension of the KA dipeptide at the C-terminal in comparison with α-scoliidine. Conclusion Comprehensive LC-MS and MS/MS analyses from the Scolia decorata ventralis venom displayed the component profile of this venom. β-scoliidine showed an effective cytoprotective effect, probably due to the observed increase in the number of cells. This is the first report of solitary wasp venom peptides showing neuroprotective activity.(AU)

Virucidal activity of oriental hornet Vespa orientalis venom against hepatitis C virus

Background Hepatitis C virus (HCV) infection is a major worldwide health problem that can cause liver fibrosis and hepatocellular carcinoma (HCC). The clinical treatment of HCV infection mainly relies on the use of direct-acting antivirals (DAAs) that are usually expensive and have side effects. Therefore, achieving the discovery of more successful agents is always urgent. In this context, antiviral compounds that inhibit viral infections and disease progression with important therapeutic activities have been identified in animal venoms including arthropod toxins. This indicates that arthropod venoms represent a good natural source of promising candidates for new antivirals. Methods The antiviral activity of the wasp venom (WV), isolated from the Oriental hornet (Vespa orientalis), was assessed using cell culture technique with human hepatocellular carcinoma-derived cell line (Huh7it-1) and the recombinant strain of HCV genotype 2a (JFH1). Results The results revealed that WV inhibited HCV infectivity with 50% inhibitory concentration (IC50) of 10 ng/mL, while the 50% cytotoxic concentration (CC50) was 11,000 ng/mL. Time of addition experiment showed that the WV blocked HCV attachment/entry to the cells probably through virucidal effect. On the other hand, the venom showed no inhibitory effect on HCV replication. Conclusion WV can inhibit the entry stage of HCV infection at non-cytotoxic concentrations. Therefore, it could be considered a potential candidate for characterization of natural anti-HCV agents targeting the entry step.(AU)

Accidente por himenópteros: reporte de caso / Hymenoptera accident: case report

Resumen Los himenópteros es una de las clasificaciones de los insectos, constituida por principalmente tres tipos, la abeja, la avispa y la hormiga de fuego, que provocan picaduras con veneno, generando desde efectos locales hasta sistémicos, con repercusiones leves o mortales sino reciben una atención médica oportuna. Las reacciones sistémicas son dependientes de la respuesta inmunológica, así como de la cantidad de las picaduras. Se presentaran dos casos de fallecimiento a causa de accidente por himenópteros tipo abejas, diagnosticados por la historia médicolegal, hallazgos de autopsia relacionado al efecto sistémico del veneno de las abejas y circunstancias relacionadas a la muerte.

Abstract Hymenoptera is one of the classifications of insects, consisting mainly of three types, the bee, the wasp and the fire ant, which cause pitting with venom generating from local to systemic effects, with slight or fatal repercussions but receive timely medical attention. Systemic reactions are dependent on the immune response, as well as the number of bites. There will be two cases of death due to an accident by hymenopterans type bees, diagnosed by medical-legal history, autopsy findings related to the systemic effect of bee venom and circumstances related to death will be presented.

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.

Biochemical characterization of a phospholipase A2 homologue from the venom of the social wasp Polybia occidentalis

Background: Wasp venoms constitute a molecular reservoir of new pharmacological substances such as peptides and proteins, biological property holders, many of which are yet to be identified. Exploring these sources may lead to the discovery of molecules hitherto unknown. This study describes, for the first time in hymenopteran venoms, the identification of an enzymatically inactive phospholipase A2 (PLA2) from the venom of the social wasp Polybia occidentalis. Methods: P. occidentalis venom was fractioned by molecular exclusion and reverse phase chromatography. For the biochemical characterization of the protein, 1D and 2D SDS-PAGE were performed, along with phospholipase activity assays on synthetic substrates, MALDI-TOF mass spectrometry and sequencing by Edman degradation. Results: The protein, called PocTX, was isolated using two chromatographic steps. Based on the phospholipase activity assay, electrophoresis and mass spectrometry, the protein presented a high degree of purity, with a mass of 13,896. 47 Da and a basic pI. After sequencing by the Edman degradation method, it was found that the protein showed a high identity with snake venom PLA2 homologues. Conclusion: This is the first report of an enzymatically inactive PLA2 isolated from wasp venom, similar to snake PLA2 homologues.

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.(AU)

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

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 (4297 %) 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 (/)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.

In vitro antibacterial effect of wasp (Vespa orientalis) venom

The emergence of antibacterial resistance against several classes of antibiotics is an inevitable consequence of drug overuse. As antimicrobial resistance spreads throughout the globe, new substances will always be necessary to fight against multidrug-resistant microorganisms. Venoms of many animals have recently gained attention in the search for new antimicrobials to treat infectious diseases. Thefore, the present study aimed to study the antibacterial effects of wasp (Vespa orientalis) crude venom. Two gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two gram-negative ones (Escherichia coli and Klesiella pneumonia) were compared for their sensitivity to the venom by determining the inhibition zone (Kirby-Bauer method) and minimum inhibitory concentration (MIC). A microbroth kinetic system based on continuous monitoring of changes in the optical density of bacterial growth was also used for determination of antimicrobial activity.

In vitro antibacterial effect of wasp (Vespa orientalis) venom

The emergence of antibacterial resistance against several classes of antibiotics is an inevitable consequence of drug overuse. As antimicrobial resistance spreads throughout the globe, new substances will always be necessary to fight against multidrug-resistant microorganisms. Venoms of many animals have recently gained attention in the search for new antimicrobials to treat infectious diseases. Thefore, the present study aimed to study the antibacterial effects of wasp (Vespa orientalis) crude venom. Two gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two gram-negative ones (Escherichia coli and Klesiella pneumonia) were compared for their sensitivity to the venom by determining the inhibition zone (Kirby-Bauer method) and minimum inhibitory concentration (MIC). A microbroth kinetic system based on continuous monitoring of changes in the optical density of bacterial growth was also used for determination of antimicrobial activity.

Effects of the European hornet ( Vespa crabro Linnaeus 1761) crude venom on its own species

Background Lethal dose 50% is a classical index of toxicity that usually employs small rodents as experimental animals. Therefore, scarce data are available on the effects of venom on invertebrates, particularly the impact of wasp venom on its own species. Findings In the present study, the lethality of Vespa crabro venom on its own species was studied. Lethal dose 50% values of crude venom on workers of hornet Vespa crabro were estimated to be 4.0 mg/kg of body weight. Conclusions Wasps can use their venom apparatus effectively when attacking foreign workers that appear in the immediate vicinity of their nest. The toxins released during stinging are potent enough to kill. The result of this study eliminates the popular myth that venomous animals can be resistant to their own venom.(AU)

Alergia a veneno de himenópteros na criança / Hymenoptera venom allergy in children

Objetivos: A alergia a veneno de himenópteros pode condicionar a vida da criança de forma significativa. Pretende-se, com a exposição de dois casos clínicos e uma breve revisão do tema, salientar a importância da referenciação dessas crianças a consultas especializadas, para início de dessensibilização.Descrição dos casos: Duas crianças, aos três e aos seis anos, tiveram anafilaxia a picada de vespa e abelha, respectivamente. Em ambas, após a determinação de IgE específica e confirmação alergológica, iniciou-se dessen-sibilização com veneno de himenópteros em esquema ultra-rush, sem intercorrências relevantes, apenas edema no local da injeção. Após doze meses de injeções a cada quatro semanas, recebem agora manutenção com injeções a cada seis semanas. No primeiro caso, a criança foi picada por vespa aos dez meses de imunoterapia, desencadeando apenas reação local diminuta.Conclusões: Em ambos os casos, a imunoterapia específica subcutânea com veneno em esquema ultra-rush foisegura e eficaz, oferecendo o conforto de um menor número de injeções e de deslocamentos ao hospital na fasede indução. A manutenção da terapêutica já demonstrou efeito protetor na reexposição ao veneno em uma dascrianças.

clinical cases and a brief review on the topic, emphasizing the importance of referral of these children to specialized care for early desensitization.Cases description: Two children, at three and six years, had anaphylactic reaction to wasp and bee stings, respectively. In both cases, after the determination of specific IgE and allergologic confirmation, desensitization with hymenoptera venom in ultra-rush regimen was done, without relevant side effect apart from swelling at the injection site. After twelve months of injections every four weeks, the children are now receiving maintenance injections every six weeks. In the first case, the child was stung by wasp at ten months of immunotherapy, triggering only small localreaction.Conclusions: In both cases, the subcutaneous venom immunotherapy with ultra-rush regimen was safe and effective, providing the comfort of a smaller number of injections and hospital visits during the induction phase. Maintenance therapy has demonstrated a protective effect on re-exposure to the poison in one child.

Evaluation of effects of photooxidized Vespa orientalis venom on memory and learning in rats

Wasp venom is mixture of complex proteins that have several physical and pharmacological properties. The photochemical detoxification of Vespa orientalis venom is expected to generate photooxidized venom sac extract (PVSE). Antigenically active PVSE is obtained by exposing the venom sac extract (VSE) of Vespa orientalis to ultraviolet radiation in the presence of methylene blue. The aim of the present work was to evaluate the effect of PVSE on learning and memory of rats. Detoxification of PVSE was evident since treated mice had longer survival time than the group of mice treated with VSE. Photooxidized VSE of V. orientalis revealed enhancement on learning and memory by shortening the time to reach food (TRF) in T-maze. In a 28-day study with rats, we observed that PVSE significantly decreased transfer latency (TL) in elevated plus maze (EPM), significantly increased step down latency (SDL), diminished step down errors (SDE) and time spent in shock zone (TSS) in step down avoidance test. Thus, we concluded that although there is a possibility of employing PVSE in the treatment of Alzheimer, dementia or neurodegenerative illness as a non-herbal and non-synthetic alternative for patients who do not respond to available therapy, further investigation is still required.(AU)

A new scenario of bioprospecting of Hymenoptera venoms through proteomic approach

Venoms represent a huge and essentially unexplored reservoir of bioactive components that may cure diseases that do not respond to currently available therapies. This review select advances reported in the literature from 2000 to the present about the new scenario of Hymenoptera venom composition. On account of new technologies in the proteomic approach, which presents high resolution and sensitivity, the combination of developments in new instruments, fragmentation methods, strategic analysis, and mass spectrometry have become indispensable tools for interrogation of protein expression, molecule interaction, and post- translational modifications. Thus, the biochemical characterization of Hymenoptera venom has become a major subject of research in the area of allergy and immunology, in which proteomics has been an excellent alternative to assist the development of more specific extracts for diagnosis and treatment of hypersensitive patients to Hymenoptera venoms.

Renal- and calcium-dependent vascular effects of Polybia paulista wasp venom

In the present study, the effects of Polybia paulista venom (PPV) on renal and vascular tissues were investigated. Isolated kidneys perfused with PPV (1 and 3 ìg/mL) had increased perfusion pressure, renal vascular resistance, urinary flow, and glomerular filtration rate; and reduced sodium tubular transport. Histological evaluation demonstrated deposits of proteins in Bowman's space and tubular lumen, and focal areas of necrosis. The venom promoted a cytotoxic effect on Madin-Darby canine kidney (MDCK) cells. A significant increase in lactic dehydrogenase levels was observed in response to venom exposure. In isolated mesenteric vascular beds, pressure and vascular resistance augmented in a dose-dependent manner. PPV increased the contractility of aortic rings maintained under basal tension. This contractile response was inhibited when preparations were maintained in Ca2+-free medium. Likewise, verapamil, a voltage-gated calcium channel blocker, also inhibited the contractile response. In this study, phentolamine, a blocker of á-adrenergic receptor blocker, significantly reduced the contractile effect of PPV in the aortic ring. In conclusion, PPV produced nephrotoxicity, which suggests a direct effect on necrotic cellular death in renal tubule cells. The vascular contractile effect of PPV appears to involve calcium influx through voltage-gated calcium channels via adrenergic regulation.

Specific immunotherapy using Hymenoptera venom: systematic review / Imunoterapia específica com venenos de Hymenoptera: revisão sistemática

CONTEXT AND OBJECTIVE: The only effective treatment for patients who have severe reactions after Hymenoptera stings is venom immunotherapy. The aim of this study was to review the literature to assess the effects of venom immunotherapy among patients presenting severe reactions after Hymenoptera stings. DESIGN AND SETTING: Randomized controlled trials in the worldwide literature were reviewed. The manuscript was produced in the Discipline of Allergy and Clinical Immunology, Universidade de São Paulo (USP). METHODS: Randomized controlled trials involving venom immunotherapy versus placebo or only patient follow-up were evaluated. The risk of systemic reactions after specific immunotherapy was evaluated by calculating odds ratios (OR) and their 95 percent confidence intervals. RESULTS: 2,273 abstracts were identified by the keywords search. Only four studies were included in this review. The chi-square test for heterogeneity showed that two studies were homogeneous and could be included in a meta-analysis. By combining the two studies, the odds ratio became significant: 0.29 (0.10-0.87). However, analysis on the severity of the reactions after immunotherapy showed that the benefits may not be so significant because the reactions were mostly similar to or milder than the original reaction. CONCLUSIONS: Specific immunotherapy should be recommended for adults and children with moderate to severe reactions, but there is no need to prescribe it for children with skin reactions alone, especially if the exposure is very sporadic. On the other hand, the risk-benefit relation should always be assessed in each case.

CONTEXTO E OBJETIVO: O único tratamento eficaz para pacientes que têm reações graves após ferroada de Hymenoptera é a imunoterapia com veneno. O objetivo deste estudo foi rever a literatura para avaliar os efeitos da imunoterapia com veneno em pacientes com reações graves após ferroada de Hymenoptera. TIPO DE ESTUDO E LOCAL: Foram revisados na literatura mundial ensaios clínicos controlados e aleatórios. O manuscrito foi realizado na Disciplina de Alergia e Imunologia Clínica, Universidade de São Paulo (USP). MÉTODOS: Ensaios clínicos controlados e aleatórios envolvendo imunoterapia com veneno de Hymenoptera versus placebo ou apenas acompanhamento dos pacientes foram avaliados. Realizada imunoterapia específica, o risco de reações sistêmicas foi avaliado através de cálculo do "odds ratio" e intervalo de confiança de 95 por cento. RESULTADOS: 2.273 resumos foram identificados na busca pelas palavras chave. Apenas quatro estudos foram incluídos nesta revisão. O teste qui-quadrado de heterogeneidade mostrou que dois estudos foram homogêneos e puderam ser incluídos na metanálise. Ao combinar os dois estudos, o "odds ratio" passou a ser significativo: 0.29 (0.10-0.87). Entretanto, ao analisar a gravidade das reações ocorridas após a imunoterapia, observou-se que os benefícios podem não ser tão relevantes, pois as reações foram, na grande maioria, ou mais leves ou semelhantes à reação original. CONCLUSÕES: A imunoterapia específica deve ser recomendada para adultos e crianças com reações moderadas a graves, porém não há necessidade de prescrevê-la para as crianças apenas com reações cutâneas, especialmente se a exposição é muito esporádica. No outro lado, a relação risco-benefício deve ser sempre avaliada em cada caso.

Alergia al venono de himenópteros / Hymenoptera venom allergy

La alergia al veneno de himenópteros es un hecho epidemiológicamente significativo. Alrededor del 0.15% al 3% de la población general tiene historia de reacciones sistémicas causada por picaduras de insectos. Entre los himenópteros más comunes que provocan este tipo de reacciones se encuentran: abejas, abejorros, avispas y hormigas. Las manifestaciones clínicas varian desde reacciones locales (eritema, edema, prurito o dolor) hasta reacciones sitémicas, e incluso shock anafilçactico con riesgo vital. El manejo inmediato depende de la intensidad de la reacción y abarca desde la aplicaión de frío local y el uso de antihistamínicos orales y corticoides tópicos y orales hasta, en los casos más severos, la administración de adrenaina inyectable. En relación con el tratamiento a largo plazo, la inmunoterapia específica ha demostrado ser muy efectiva en la reducción del riesgo de reacción severa frente a la posterior picadura de insecto.

Inmunoterapia con veneno de himenópteros: presentación de diez casos clínicos / Immunotherapy against hymenoptera venom: Report of ten patients

Background: Immunotherapy can be used to treat allergic reactions to insect stings, specially bees and wasps. Aim: To report the experience with immunotherapy with aqueous extracts of hymenoptera venoms (bees and wasps). Material and methods: Ten patients aged 6 to 58 years were treated in an allergy center of a University Clinical Hospital. The medical indication for this treatment was, in all patients, anaphylactic reactions after hymenoptera stings. Immunotherapy was carried out using standardized vaccines (Aqueous extracts Venomvac LETI, Spain), applied in a traditional protocol, with subcutaneous injections. This protocol had two phases: a buildup phase (between weeks 1 and 13) and a monthly maintenance phase, from the 13th week. The monthly maintenance dose was 100 fig of hymenoptera specific venom extract. Results: Six patients had adverse reactions of different severity, during the treatment protocols and all had a good response to immediate therapeutic measures. After these events, they followed the protocol without problems. Two patients, treated with bee vaccines, suffered an accidental bee sting during the maintenance phase and they developed only local reactions. Conclusions: The lack of adverse reactions to bee stings in these two patients indicates the acquisition of clinical tolerance.

Papel de las proteínas G heterotriméricas sensibles a mastoparán en la activación muscarínica del músculo liso de vías aéreas / Paper of heterotrimetric G-proteins sensitive to mastoparan in the muscarinic activation of tracheal smooth muscle

La activación muscarínica del músculo liso traqueal de bovino (MLTB) genera de dos señales de GMPc (20 y 60s), la primera atribuida a la Guanililciclasa soluble (sGC) y la segunda a la Guanililciclasa particulada (NPR-GC). Existen evidencias que la activación muscarínica es mediada. En este sentido determinamos el efecto del tetradecapéptido desacoplante de las proteínas G Mastoparán sobre dicha activación, evaluando los niveles de GMPc y la actividad contráctil del MLTB. Mastoparán inhibió en un 63 por ciento la primera señal de GMPc y desapareció la segunda. Posteriormente evaluamos el efecto de Mastoparán sobre las sGC y NPR-GC. La enzima sGG se evalúo utilizando el Nitroprusiato de Sodio (SNP), el cual indujo un patrón bifásico de acumulación GMPc, las NPR-GC, fueron evaluadas utilizando los péptidos natriuréticos ANP y CNP-53 los cuales indujeron patrones monotónico y bifásicos respectivamente. Observando en los tres casos que la preincubación con Mastoparán, disminuyó los niveles de GMPc de manera significativa (p<0.05). Dicho efecto fue atribuido a proteínas Gi ya que al pre-tratar el MLTB con PTX desaparecía el efecto de Mastoparán. También evaluamos la actividad contráctil del MLTB, encontrándose que Mastoparán se comportan como un "inhibidor no competitivo" de la contracción muscarínica, sin comprometer la integridad funcional de la maquinaria contráctil ya que las aminas biogenas histamina y serotonina produjeron potentes contracciones. Estos hallazgos nos sugieren que la inhibición selectiva de las señales de GMPc esta relacionada con el bloqueo de la contracción muscarínica.

Ultramorphological analysis of the venom glands and their histochemical relationship with the convoluted glands in the primitive social paper wasp Polistes versicolor (Hymenoptera: vespiade)

The venom glands are part of the most important defense weapon in Aculeata: the venom apparatus. The arrangement of these glands can vary among species, but in general they are composed of long secretory tubules connected to a muscular sac-like reservoir. Although the occurrence of these variations has been documented, many studies neglected the existence of a well-developed secretory portion in the lumen of the reservoir named convoluted gland. This study is an ultramorphological analysis of the venom glands and their histochemical relationship with the convoluted glands in the primitive social wasp Polistes versicolor. In this wasp, the venom glands are constituted by two tubular portions tha penetrate individually in the venom reservoir, inside of which we can find the convoluted glands. Besides morphological differences in their cells, histochemical analysis of the venom and convoluted glands clearly show differences between them. While the venom glands indicate positive reaction only for proteins, the convoluted glands present positive reaction for proteins, neutral glycoconjugates, and lipids. The secretion of the convoluted gland cells may modify the compounds passing through the embedded tubular region