RESUMO
Caterpillars of the Neotropical genus Lonomia (Lepidoptera: Saturniidae) are responsible for some fatal envenomation of humans in South America inducing hemostatic disturbances in patients upon skin contact with the caterpillars' spines. Currently, only two species have been reported to cause hemorrhagic syndromes in humans: Lonomia achelous and Lonomia obliqua. However, species identifications have remained largely unchallenged despite improved knowledge of venom diversity and growing evidence that the taxonomy used over past decades misrepresents and underestimates species diversity. Here, we revisit the taxonomic diversity and distribution of Lonomia species using the most extensive dataset assembled to date, combining DNA barcodes, morphological comparisons, and geographical information. Considering new evidence for seven undescribed species as well as three newly proposed nomenclatural changes, our integrative approach leads to the recognition of 60 species, of which seven are known or strongly suspected to cause severe envenomation in humans. From a newly compiled synthesis of epidemiological data, we also examine the consequences of our results for understanding Lonomia envenomation risks and call for further investigations of other species' venom activities. This is required and necessary to improve alertness in areas at risk, and to define adequate treatment strategies for envenomed patients, including performing species identification and assessing the efficacy of anti-Lonomia serums against a broader diversity of species.
Assuntos
Venenos de Artrópodes , Mariposas , Animais , Humanos , Larva , Venenos de Artrópodes/toxicidade , Hemorragia , América do SulRESUMO
Contact with Lonomia caterpillars can cause severe envenomation with hemorrhagic syndrome, consumptive coagulopathy, acute renal failure, and death. In Brazil, an antivenom was produced using extracts from L. obliqua caterpillar bristles as antigen and has been used in other countries in South America to treat envenomation caused by distinct species of Lonomia. This study aimed to characterize the activities of toxins from Lonomia descimoni caterpillars found in Colombia and the neutralization of these toxins by the Brazilian Lonomia antivenom. The protein composition and coagulant, phospholipase A2, hyaluronidase, and defibrinogenating activities were evaluated and compared with the same parameters of the L. obliqua bristle extract. Immune recognition and the neutralizing ability of Lonomia antivenom were also determined. The results showed that the L. descimoni bristle extract presented marked differences in electrophoretic and mass spectrometry profiles and had coagulant, phospholipase A2, and hyaluronidase activities significantly less intense than those of the L. obliqua extract. In rats, L. descimoni extract induced coagulopathy and hemoglobinuria when injected by intravenous or intraperitoneal routes. The Lonomia antivenom recognized the toxins in the extract of L. descimoni and reversed the experimental envenomation in rats. Our results indicate that L. descimoni caterpillars possess toxins with weaker activities than those of L. obliqua but with the potential to cause envenomation. Moreover, the Lonomia antivenom recognized and neutralized the toxins in the L. descimoni bristle extract.
Assuntos
Venenos de Artrópodes , Transtornos da Coagulação Sanguínea , Lepidópteros , Mariposas , Ratos , Animais , Antivenenos/farmacologia , Antivenenos/uso terapêutico , Mariposas/química , Hialuronoglucosaminidase , Venenos de Artrópodes/toxicidade , Fosfolipases A2 , BrasilRESUMO
Linear cationic venom peptides are antimicrobial peptides (AMPs) that exert their effects by damaging cell membranes. These peptides can be highly specific, and for some, a significant therapeutic value was proposed, in particular for treatment of bacterial infections. A prolific source of novel AMPs are arthropod venoms, especially those of hitherto neglected groups such as pseudoscorpions. In this study, we describe for the first time pharmacological effects of AMPs discovered in pseudoscorpion venom. We examined the antimicrobial, cytotoxic, and insecticidal activity of full-length Checacin1, a major component of the Chelifer cancroides venom, and three truncated forms of this peptide. The antimicrobial tests revealed a potent inhibitory activity of Checacin1 against several bacteria and fungi, including methicillin resistant Staphylococcus aureus (MRSA) and even Gram-negative pathogens. All peptides reduced survival rates of aphids, with Checacin1 and the C-terminally truncated Checacin11-21 exhibiting effects comparable to Spinosad, a commercially used pesticide. Cytotoxic effects on mammalian cells were observed mainly for the full-length Checacin1. All tested peptides might be potential candidates for developing lead structures for aphid pest treatment. However, as these peptides were not yet tested on other insects, aphid specificity has not been proven. The N- and C-terminal fragments of Checacin1 are less potent against aphids but exhibit no cytotoxicity on mammalian cells at the tested concentration of 100 µM.
Assuntos
Anti-Infecciosos , Proteínas de Artrópodes , Venenos de Artrópodes , Citotoxinas , Inseticidas , Sequência de Aminoácidos , Animais , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Anti-Infecciosos/toxicidade , Afídeos/efeitos dos fármacos , Aracnídeos , Proteínas de Artrópodes/química , Proteínas de Artrópodes/farmacologia , Proteínas de Artrópodes/toxicidade , Venenos de Artrópodes/química , Venenos de Artrópodes/farmacologia , Venenos de Artrópodes/toxicidade , Citotoxinas/química , Citotoxinas/farmacologia , Citotoxinas/toxicidade , Cães , Inseticidas/química , Inseticidas/farmacologia , Inseticidas/toxicidade , Células Madin Darby de Rim Canino , Alinhamento de SequênciaRESUMO
Accidents with venomous animals are a public health issue worldwide. Among the species involved in these accidents are scorpions, spiders, bees, wasps, and other members of the phylum Arthropoda. The knowledge of the function of proteins present in these venoms is important to guide diagnosis, therapeutics, besides being a source of a large variety of biotechnological active molecules. Although our understanding about the characteristics and function of arthropod venoms has been evolving in the last decades, a major aspect crucial for the function of these proteins remains poorly studied, the posttranslational modifications (PTMs). Comprehension of such modifications can contribute to better understanding the basis of envenomation, leading to improvements in the specificities of potential therapeutic toxins. Therefore, in this review, we bring to light protein/toxin PTMs in arthropod venoms by accessing the information present in the UniProtKB/Swiss-Prot database, including experimental and putative inferences. Then, we concentrate our discussion on the current knowledge on protein phosphorylation and glycosylation, highlighting the potential functionality of these modifications in arthropod venom. We also briefly describe general approaches to study "PTM-functional-venomics", herein referred to the integration of PTM-venomics with a functional investigation of PTM impact on venom biology. Furthermore, we discuss the bottlenecks in toxinology studies covering PTM investigation. In conclusion, through the mining of PTMs in arthropod venoms, we observed a large gap in this field that limits our understanding on the biology of these venoms, affecting the diagnosis and therapeutics development. Hence, we encourage community efforts to draw attention to a better understanding of PTM in arthropod venom toxins.(AU)
Assuntos
Animais , Venenos de Artrópodes/toxicidade , Processamento de Proteína Pós-Traducional , Fosforilação , Escorpiões , Espectrometria de Massas/métodos , Aranhas , Vespas , Abelhas , GlicosilaçãoRESUMO
As a tribute to Butantan Institute in its 120th anniversary, this review describes some of the scientific research efforts carried out in the study of Lonomia envenoming in Brazil, a country where accidents with caterpillars reach over 42,000 individuals per year (especially in South and Southeast Brazil). Thus, the promising data regarding the studies with Lonomia's toxins contributed to the creation of new research centers specialized in toxinology based at Butantan Institute, as well as to the production of the antilonomic serum (ALS), actions which are in line with the Butantan Institute mission "to research, develop, manufacture, and provide products and services for the health of the population". In addition, the study of the components of the Lonomia obliqua bristle extract led to the discovery of new molecules with peculiar properties, opening a field of knowledge that could lead to the development and innovation of new drugs aimed at cell regeneration and inflammatory diseases.
Assuntos
Venenos de Artrópodes/toxicidade , Borboletas/fisiologia , Mordeduras e Picadas de Insetos/terapia , Animais , Brasil/epidemiologia , Humanos , Mordeduras e Picadas de Insetos/epidemiologia , Larva/fisiologiaRESUMO
Among the Chilopoda class of centipede, the Cryptops genus is one of the most associated with envenomation in humans in the metropolitan region of the state of São Paulo. To date, there is no study in the literature about the toxins present in its venom. Thus, in this work, a transcriptomic characterization of the Cryptops iheringi venom gland, as well as a proteomic analysis of its venom, were performed to obtain a toxin profile of this species. These methods indicated that 57.9% of the sequences showed to be putative toxins unknown in public databases; among them, we pointed out a novel putative toxin named Cryptoxin-1. The recombinant form of this new toxin was able to promote edema in mice footpads with massive neutrophils infiltration, linking this toxin to envenomation symptoms observed in accidents with humans. Our findings may elucidate the role of this toxin in the venom, as well as the possibility to explore other proteins found in this work.
Assuntos
Venenos de Artrópodes/química , Venenos de Artrópodes/toxicidade , Quilópodes/química , Animais , Quilópodes/genética , Edema/induzido quimicamente , Perfilação da Expressão Gênica , Soros Imunes , Masculino , Camundongos Endogâmicos BALB C , Proteoma , Coelhos , Proteínas RecombinantesRESUMO
The significant incidence of deforestation in South America culminates in the contact of humans with typical forests species. Among these species, one may highlight Lonomia obliqua caterpillar, which, when touched by humans, can poison them through their bristles. Therefore, better acknowledging the mechanisms involved in envenomation caused by Lonomia obliqua caterpillar bristle extract (LOCBE) may contribute to further treatments. Recently, we demonstrated that LOCBE induces a pro-inflammatory profile in endothelial cells; thus, we decided to investigate the effects of LOCBE on human polymorphonuclear neutrophils (PMN), which are the first leukocytes that migrate to the inflammatory focus. Our results showed that treatment with LOCBE induced PMN chemotaxis together with alterations in actin cytoskeleton and focal adhesion kinase (FAK) activation, favoring migration. Concurrently, LOCBE induced PMN adhesion to matrix proteins, such as collagen IV, fibronectin, and fibrinogen. Moreover, we observed that LOCBE attenuated PMN apoptosis and increased reactive oxygen species (ROS) production together with nuclear factor kB (NF-κB) activation-a redox-sensitive transcription factor-as well as interleukin (IL)-1ß and IL-8 release. We call attention to the ROS-dependent effect of LOCBE on increased cell migration once an antioxidant treatment reverted it. In summary, we report that LOCBE activates PMN, inducing pro-inflammatory responses modulated by ROS.
Assuntos
Venenos de Artrópodes/toxicidade , Lepidópteros/fisiologia , Neutrófilos/efeitos dos fármacos , Animais , Adesão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Quimiotaxia , Cricetinae , Humanos , Tegumento Comum , Larva/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Pele/efeitos dos fármacosRESUMO
Envenomation caused by contact with Lonomia obliqua bristles is characterized by pain, an intense systemic proinflammatory reaction and disturbances in the coagulation cascade that can cause severe clinical manifestations and death. However, the role of immune system components in these effects is still poorly understood. In this study, we evaluated the cytotoxic effect of L. obliqua venom on THP-1-derived macrophages and its ability to modulate inflammatory markers, as well as the cytokine and chemokine release profile. Our results show that L. obliqua venom is able to directly exert a potent pro-inflammatory reaction in macrophages, characterized by the activation of the NF-κB transcription factor pathway, the expression of CD80 and CD83, and the release of pro-inflammatory mediators such as TNF-α, IL-1ß, IL-6, IL-8 and CXCL10. These results suggest that macrophages can play an important role during the orchestration of the inflammatory response present in envenomation caused by Lonomia obliqua caterpillars.
Assuntos
Venenos de Artrópodes/toxicidade , Larva , Macrófagos/efeitos dos fármacos , NF-kappa B/metabolismo , Animais , Antígenos CD/metabolismo , Antígeno B7-1/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Citocinas/genética , Citocinas/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Imunoglobulinas/metabolismo , Lepidópteros , Macrófagos/metabolismo , Glicoproteínas de Membrana/metabolismo , Células THP-1 , Antígeno CD83RESUMO
BACKGROUND: Envenomation by the South American Lonomia saturniid caterpillars, named lonomism, constitutes an emerging and somewhat neglected public health issue in Argentina and neighboring countries. Considering that there is an intricate relationship between environment and human health in such cases, this study aimed to analyze the eco-epidemiological profile of 40 accidents and 33 occurrences of Lonomia spp. in Misiones (Argentina) between January 2014 and May 2020. METHODOLOGY/PRINCIPAL FINDINGS: We described the eco-epidemiological variables and characterized the abiotic scenario of such cases. Additionally, we obtained a density map that shows the punctual intensity of Lonomia records throughout Misiones. Most of the accidents occurred in the Department of Guaraní and involved male victims younger than 20 years old. The accidental/occasional occurrence of Lonomia spp. (considering both adult and caterpillar stages together) was significantly higher in the rural area, whereas only adult specimens were found in urban areas. We determined that the presence of this insect in Misiones is positively related to higher temperatures and solar radiation, and larger precipitation and evapotranspiration throughout the year. CONCLUSION/SIGNIFICANCE: This study represents an initial step towards the global understanding of lonomism as a public health problem in Argentina. It provides a map of the risk level for this envenomation in Misiones, which could help authorities address public health policy efforts to implement sustainable strategies for prevention and response to this threat in Northeastern Argentina and neighboring regions.
Assuntos
Venenos de Artrópodes/toxicidade , Mordeduras e Picadas de Insetos/parasitologia , Larva/fisiologia , Mariposas/fisiologia , Adolescente , Adulto , Idoso , Animais , Argentina/epidemiologia , Criança , Pré-Escolar , Ecossistema , Feminino , Humanos , Lactente , Mordeduras e Picadas de Insetos/epidemiologia , Larva/classificação , Masculino , Pessoa de Meia-Idade , Mariposas/classificação , Doenças Negligenciadas/epidemiologia , Doenças Negligenciadas/parasitologia , Saúde Pública , Adulto JovemRESUMO
Velvet ants (Hymenoptera: Mutillidae) are a family of solitary parasitoid wasps that are renowned for their painful stings. We explored the chemistry underlying the stings of mutillid wasps of the genus Dasymutilla Ashmead. Detailed analyses of the venom composition of five species revealed that they are composed primarily of peptides. We found that two kinds of mutillid venom peptide appear to be primarily responsible for the painful effects of envenomation. These same peptides also have defensive utility against invertebrates, since they were able to incapacitate and kill honeybees. Both act directly on cell membranes where they directly increase ion conductivity. The defensive venom peptides of Dasymutilla bear a striking similarity, in structure and mode of action, to those of the ant Myrmecia gulosa (Fabricius), suggesting either retention of ancestral toxins, or convergence driven by similar life histories and defensive selection pressures. Finally, we propose that other highly expressed Dasymutilla venom peptides may play a role in parasitisation, possible in delay or arrest of host development. This study represents the first detailed account of the composition and function of the venoms of the Mutillidae.
Assuntos
Venenos de Artrópodes/química , Venenos de Artrópodes/toxicidade , Comportamento Animal/efeitos dos fármacos , Himenópteros/fisiologia , Mordeduras e Picadas de Insetos/induzido quimicamente , Dor/induzido quimicamente , Fragmentos de Peptídeos/toxicidade , Sequência de Aminoácidos , Animais , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Homologia de SequênciaRESUMO
BACKGROUND: Clonal mast cell disorders and elevated basal serum tryptase (BST) levels with unknown cause(s) are associated with severe Hymenoptera venom-triggered anaphylaxis (HVA). However, some individuals with clonal disease have a normal BST level (<11.4 ng/mL). OBJECTIVE: Our aim was to evaluate whether screening for KIT p.D816V in the blood is a useful clinical tool to risk-stratify patients with venom allergy. METHODS: We prospectively recruited 374 patients with Hymenoptera allergy and no overt signs of mastocytosis who were referred to our center during the years 2018 and 2019. KIT p.D816V was determined in their peripheral blood by quantitative PCR, and tryptase genotyping was performed by droplet digital PCR. RESULTS: In all, 351 patients (93.9%) had normal levels of BST, and KIT p.D816V was detected in 8% of patients (28 of 351), predominantly in patients with the most severe Mueller grade IV anaphylaxis (18.2% [24 of 132] vs 1.8% in patients with lower grades [4 of 88 with grade III and 0 of 131 with other grades]; P < .001). In grade IV patients with a normal BST level, KIT p.D816V was associated with more severe symptoms, including a significantly higher frequency of loss of consciousness (58.3% [14 of 24] vs 34.3% [37 of 108]; P = .03) and absence of skin symptoms (41.7% [10 of 24] vs 15.7% [17 of 108]; P = .004). Among patients with a normal BST level, KIT p.D816V (OR = 10.25 [95% CI = 3.75-36.14]; P < .0001) was the major risk factor associated with severe HVA. Hereditary α-tryptasemia (HαT) due to increased germline copies of TPSAB1 encoding α-tryptase was the most common cause (65.2% [15 of 23]) of elevated BST level in patients with HVA, and together with KIT p.D816V, it accounted for 90% of BST level elevations (20 of 23) in patients with HVA. CONCLUSION: These results indicate that routine KIT p.D816V screening identifies clonal disease in high-risk patients with HVA who are regularly missed when BST level is used alone.
Assuntos
Anafilaxia , Venenos de Artrópodes/toxicidade , Testes Genéticos , Mastócitos/imunologia , Mastocitose Sistêmica , Mutação de Sentido Incorreto , Proteínas Proto-Oncogênicas c-kit , Triptases/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Substituição de Aminoácidos , Anafilaxia/genética , Anafilaxia/imunologia , Feminino , Humanos , Masculino , Mastocitose Sistêmica/genética , Mastocitose Sistêmica/imunologia , Pessoa de Meia-Idade , Proteínas Proto-Oncogênicas c-kit/genética , Proteínas Proto-Oncogênicas c-kit/imunologia , Triptases/genéticaRESUMO
AIMS: Accidental contact with the Lonomia obliqua caterpillar is a common event in southern Brazil. Envenomed victims present consumption coagulopathy, which can evolve to acute kidney injury (AKI). In the present study, we searched for AKI biomarkers and changes in molecular pathway signatures through urine proteomic analysis. METHODOLOGY: Male Wistar rats were injected with L. obliqua venom (1.5 mg/kg, via s.c.) or 0.9 % NaCl and distributed into metabolic cages. After 24 h, urine was obtained, and the set of differentially regulated proteins was analyzed by MudPIT technology in an OrbiTRAP mass spectrometer. RESULTS: L. obliqua venom leads to an increase in urine output and water and electrolyte excretion and to an increase in the albumin to creatine ratio in urine. The proteomic analysis revealed an up-regulation of tubular injury biomarkers, such as neutrophil-gelatinase associated lipocalin (NGAL) and cystatin C, in urine from envenomed rats. Several components related to the heme scavenging system were up-regulated or exclusively identified in urine from envenomed animals. There was an increase in urinary heme levels and hemoglobin subunits, hemopexin, haptoglobin, and biliverdin reductase. Similarly, kinin- and angiotensin-generating/degrading peptidases, such as kallikreins, neprilysin, plasmin, dipeptidyl peptidase IV, cathepsin D, kininogen, and neutral, basic, glutamyl, and acidic aminopeptidases, were also up-regulated in urine. CONCLUSIONS: L. obliqua envenomation induced tubular and glomerular injury, probably involving heme/hemoglobin toxicity and an imbalance in the kinin/angiotensin generating/degrading system.
Assuntos
Injúria Renal Aguda/induzido quimicamente , Aminopeptidases/metabolismo , Venenos de Artrópodes/toxicidade , Hemoglobinúria , Lepidópteros , Proteômica , Aminopeptidases/química , Animais , Heme , Hemoglobinas , Larva/fisiologia , Masculino , Ratos , Ratos Wistar , Urinálise , Urina/químicaRESUMO
Chagas disease is an important disease affecting millions of patients in the New World and is caused by a protozoan transmitted by haematophagous kissing bugs. It can be treated with drugs during the early acute phase; however, effective therapy against the chronic form of Chagas disease has yet to be discovered and developed. We herein tested the activity of solenopsin alkaloids extracted from two species of fire ants against the protozoan parasite Trypanosoma cruzi, the aetiologic agent of Chagas disease. Although IC50 determinations showed that solenopsins are more toxic to the parasite than benznidazole, the drug of choice for Chagas disease treatment, the ant alkaloids presented a lower selectivity index. As a result of exposure to the alkaloids, the parasites became swollen and rounded in shape, with hypertrophied contractile vacuoles and intense cytoplasmic vacuolization, possibly resulting in osmotic stress; no accumulation of multiple kinetoplasts and/or nuclei was detected. Overexpressing phosphatidylinositol 3-kinase-an enzyme essential for osmoregulation that is a known target of solenopsins in mammalian cells-did not prevent swelling and vacuolization, nor did it counteract the toxic effects of alkaloids on the parasites. Additional experimental results suggested that solenopsins induced a type of autophagic and programmed cell death in T. cruzi. Solenopsins also reduced the intracellular proliferation of T. cruzi amastigotes in infected macrophages in a concentration-dependent manner and demonstrated activity against Trypanosoma brucei rhodesiense bloodstream forms, which is another important aetiological kinetoplastid parasite. The results suggest the potential of solenopsins as novel natural drugs against neglected parasitic diseases caused by kinetoplastids.
Assuntos
Alcaloides/toxicidade , Venenos de Artrópodes/toxicidade , Tripanossomicidas/toxicidade , Trypanosoma cruzi/efeitos dos fármacos , Animais , Formigas/química , Apoptose , Autofagia , Células CHO , Cricetinae , Cricetulus , Macaca mulatta , Macrófagos/parasitologia , Pressão Osmótica , Trypanosoma cruzi/metabolismo , Trypanosoma cruzi/patogenicidadeRESUMO
Arthropods comprise a predominant and well-succeeded phylum of the animal kingdom that evolved and diversified in millions of species grouped in four subphyla, namely, Chelicerata (arachnids), Crustacea, Myriapoda (centipedes), and Hexapoda (insects) [...].
Assuntos
Venenos de Artrópodes , Peptídeos , Animais , Venenos de Artrópodes/química , Venenos de Artrópodes/farmacologia , Venenos de Artrópodes/uso terapêutico , Venenos de Artrópodes/toxicidade , Inseticidas/química , Inseticidas/farmacologia , Inseticidas/uso terapêutico , Inseticidas/toxicidade , Peptídeos/química , Peptídeos/farmacologia , Peptídeos/uso terapêutico , Peptídeos/toxicidadeRESUMO
Accidental contact with caterpillar bristles causes local symptoms such as severe pain, intense heat, edema, erythema, and pruritus. However, there is little functional evidence to indicate a potential mechanism. In this study, we analyzed the biological characteristics of the crude venom from the larval stage of Latoia consocia living in South-West China. Intraplantar injection of the venom into the hind paws of mice induced severe acute pain behaviors in wild type (WT) mice; the responses were much reduced in TRPV1-deficit (TRPV1 KO) mice. The TRPV1-specific inhibitor, capsazepine, significantly attenuated the pain behaviors. Furthermore, the crude venom evoked strong calcium signals in the dorsal root ganglion (DRG) neurons of WT mice but not those of TRPV1 KO mice. Among the pain-related ion channels we tested, the crude venom only activated the TRPV1 channel. To better understand the venom components, we analyzed the transcriptome of the L. consocia sebaceous gland region. Our study suggests that TRPV1 serves as a primary nociceptor in caterpillar-induced pain and forms the foundation for elucidating the pain-producing mechanism.
Assuntos
Venenos de Artrópodes/toxicidade , Larva/química , Dor/induzido quimicamente , Canais de Cátion TRPV/efeitos dos fármacos , Animais , Venenos de Artrópodes/genética , Comportamento Animal/efeitos dos fármacos , Sinalização do Cálcio/efeitos dos fármacos , Capsaicina/análogos & derivados , Capsaicina/farmacologia , Feminino , Gânglios Espinais/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nociceptores/efeitos dos fármacos , Dor/psicologia , Medição da Dor/efeitos dos fármacos , Glândulas Sebáceas/química , Canais de Cátion TRPV/antagonistas & inibidores , Canais de Cátion TRPV/genéticaRESUMO
Assassin bugs (Reduviidae) produce venoms that are insecticidal, and which induce pain in predators, but the composition and function of their individual venom components is poorly understood. We report findings on the venom system of the red-spotted assassin bug Platymeris rhadamanthus, a large species of African origin that is unique in propelling venom as a projectile weapon when threatened. We performed RNA sequencing experiments on venom glands (separate transcriptomes of the posterior main gland, PMG, and the anterior main gland, AMG), and proteomic experiments on venom that was either defensively propelled or collected from the proboscis in response to electrostimulation. We resolved a venom proteome comprising 166 polypeptides. Both defensively propelled venom and most venom samples collected in response to electrostimulation show a protein profile similar to the predicted secretory products of the PMG, with a smaller contribution from the AMG. Pooled venom samples induce calcium influx via membrane lysis when applied to mammalian neuronal cells, consistent with their ability to cause pain when propelled into the eyes or mucus membranes of potential predators. The same venom induces rapid paralysis and death when injected into fruit flies. These data suggest that the cytolytic, insecticidal venom used by reduviids to capture prey is also a highly effective defensive weapon when propelled at predators.
Assuntos
Venenos de Artrópodes/toxicidade , Comportamento Animal , Heterópteros/metabolismo , Sequência de Aminoácidos , Animais , Venenos de Artrópodes/química , Venenos de Artrópodes/genética , Heterópteros/fisiologia , Análise de Sequência de RNA , Homologia de Sequência de Aminoácidos , TranscriptomaRESUMO
Pain is a natural bioassay for detecting and quantifying biological activities of venoms. The painfulness of stings delivered by ants, wasps, and bees can be easily measured in the field or lab using the stinging insect pain scale that rates the pain intensity from 1 to 4, with 1 being minor pain, and 4 being extreme, debilitating, excruciating pain. The painfulness of stings of 96 species of stinging insects and the lethalities of the venoms of 90 species was determined and utilized for pinpointing future directions for investigating venoms having pharmaceutically active principles that could benefit humanity. The findings suggest several under- or unexplored insect venoms worthy of future investigations, including: those that have exceedingly painful venoms, yet with extremely low lethality-tarantula hawk wasps (Pepsis) and velvet ants (Mutillidae); those that have extremely lethal venoms, yet induce very little pain-the ants, Daceton and Tetraponera; and those that have venomous stings and are both painful and lethal-the ants Pogonomyrmex, Paraponera, Myrmecia, Neoponera, and the social wasps Synoeca, Agelaia, and Brachygastra. Taken together, and separately, sting pain and venom lethality point to promising directions for mining of pharmaceutically active components derived from insect venoms.
Assuntos
Venenos de Artrópodes/toxicidade , Mordeduras e Picadas de Insetos/mortalidade , Dor/induzido quimicamente , Animais , Formigas , Abelhas , Feminino , Humanos , Dose Letal Mediana , Masculino , Camundongos Endogâmicos ICR , Dor/mortalidade , Comportamento Social , VespasRESUMO
PURPOSE OF REVIEW: To update the influence of the global climate change on Hymenoptera venom allergy. RECENT FINDINGS: Climate change facilitates biological invasions of hymenopteran species and plays a role in the impact of introduced species relevant for human health. It contributes to a rise in the incidence of sting injuries and allergy reactions across the world. SUMMARY: Global climate change has contributed to the expansion and the redistribution of allergenic insect species, increasing the number of allergy cases caused by stinging insects worldwide. Imported insects are trending species in systemic reactions for multiple stings or hymenopteran venom allergy. They represent a threat for humans and a challenge for the allergists.
Assuntos
Venenos de Artrópodes/toxicidade , Mudança Climática , Himenópteros/fisiologia , Hipersensibilidade/epidemiologia , Mordeduras e Picadas de Insetos/epidemiologia , Animais , HumanosRESUMO
PURPOSE OF REVIEW: Currently, there is strong evidence about an association between hymenoptera venom anaphylaxis (HVA) and mastocytosis. This review is focused on the most relevant clinical and biological features of systemic mastocytosis associated with HVA. RECENT FINDINGS: HVA is a relatively common complication that modifies the natural course of patients with mastocytosis, particularly men with indolent systemic mastocytosis without skin lesions (ISMs-) in whom HVA can be the presenting symptom in up to around one-half of the cases. Patients with ISMs- associated with HVA are typically males with cardiovascular symptoms in the absence of itching, urticaria, and angioedema during anaphylaxis. Noteworthy, ISMs- is characterized by a low bone marrow mast cell load and a low risk for disease progression. Early and more recent studies support that specific venom immunotherapy (VIT) is a well-tolerated and effective treatment in patients with mastocytosis. SUMMARY: VIT should be given life-long to all patients with mastocytosis and proven immunoglobulin E (IgE)-mediated HVA. In patients with negative venom skin test and undetectable IgE antibodies, additional studies such as component-based allergy testing might contribute to confirm an IgE-mediated mechanism of anaphylaxis in some cases, thus providing the indication of VIT.
Assuntos
Anafilaxia , Venenos de Artrópodes/toxicidade , Dessensibilização Imunológica , Himenópteros , Mastocitose , Caracteres Sexuais , Anafilaxia/sangue , Anafilaxia/imunologia , Anafilaxia/terapia , Animais , Feminino , Humanos , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Masculino , Mastocitose/sangue , Mastocitose/imunologia , Mastocitose/terapiaRESUMO
PURPOSE OF REVIEW: To recognize the relevance of serum tryptase measurement as a useful tool for the diagnosis of allergic diseases and mast cell disorders. RECENT FINDINGS: Recent data on the role of mast cells and tryptase in allergic and other diseases provide new understanding into the mechanisms and causes of anaphylaxis. SUMMARY: Measurement of transiently elevated tryptase levels shortly after a severe reaction can help elucidate mechanism behind the reaction in identifying mast cell activation. Hymenoptera venom allergy represents an important cause of morbidity and mortality worldwide. Venom allergy is a typical IgE-mediated reaction because of sensitization to one or more allergens of the venom, and accounts for 1.5-34% of all cases of anaphylaxis. There is a preferential association between insect venom allergy and mastocytosis. The diagnosis of a clonal mast cell disease leads to therapeutic consequences concerning the treatment of venom allergy. In conclusion, baseline tryptase levels support the clinical diagnosis of anaphylaxis and mast cell disorders, determine venom immunotherapy treatment and are relevant in deciding on lifelong treatment.