RESUMO
Venoms of solitary wasps are utilized for prey capture (insects and spiders), paralyzing them with a stinger injection to be offered as food for their larvae. Thus, the identification and characterization of the components of solitary wasp venoms can have biotechnological application. In the present study, the venom components profile of a solitary scoliid wasp, Campsomeriella annulata annulata, was investigated through a comprehensive analysis using LC-MS and -MS/MS. Online mass fingerprinting revealed that the venom extract contains 138 components, and MS/MS analysis identified 44 complete sequences of the peptide components. The peptides are broadly divided into two classes: bradykinin-related peptides, and linear α-helical peptides. Among the components of the first class, the two main peptides, α-campsomerin (PRLRRLTGLSPLR) and ß-campsomerin (PRLRRLTGLSPLRAP), had their biological activities evaluated. Both peptides had no effects on metallopeptidases [human neprilysin (NEP) and angiotensin-converting enzyme (ACE)] and acetylcholinesterase (AChE), and had no cytotoxic effects. Studies with PC12 neuronal cells showed that only α-campsomerin was able to enhance cell viability, while ß-campsomerin had no effect. It is noteworthy that the only difference between the primary structures from these peptides is the presence of the AP extension at the C-terminus of ß-campsomerin, compared to α-campsomerin. Among the linear α-helical peptides, annulatin (ISEALKSIIVG-NH2) was evaluated for its biological activities. Annulatin showed histamine releasing activity from mast cells and low hemolytic activity, but no antimicrobial activities against all microbes tested were observed. Thus, in addition to providing unprecedented information on the whole components, the three peptides selected for the study suggest that molecules present in solitary scoliid wasp venoms may have interesting biological activities.
Assuntos
Proteínas de Insetos/química , Proteínas de Insetos/toxicidade , Células PC12/efeitos dos fármacos , Fenômenos Toxicológicos/efeitos dos fármacos , Venenos de Vespas/química , Venenos de Vespas/toxicidade , Animais , Japão , RatosRESUMO
Among venomous animals, Hymenoptera have been suggested as a rich source of natural toxins. Due to their broad ecological diversity, venom from Hymenoptera insects (bees, wasps and ants) have evolved differentially thus widening the types and biological functions of their components. To date, insect toxinology analysis have scarcely uncovered the complex composition of bee, wasp and ant venoms which include low molecular weight compounds, highly abundant peptides and proteins, including several allergens. In Hymenoptera, these complex mixtures of toxins represent a potent arsenal of biological weapons that are used for self-defense, to repel intruders and to capture prey. Consequently, Hymenoptera venom components have a broad range of pharmacological targets and have been extensively studied, as promising sources of new drugs and biopesticides. In addition, the identification and molecular characterization of Hymenoptera venom allergens have allowed for the rational design of component-resolved diagnosis of allergy, finally improving the outcome of venom immunotherapy (VIT). Until recently, a limited number of Hymenoptera venoms had been unveiled due to the technical limitations of the approaches used to date. Nevertheless, the application of novel techniques with high dynamic range has significantly increased the number of identified peptidic and proteinaceous toxins. Considering this, the present review summarizes the current knowledge about the most representative Hymenoptera venom peptides and proteins which are under study for a better understanding of the insect-caused envenoming process and the development of new drugs and biopesticides.
Assuntos
Venenos de Artrópodes/química , Venenos de Artrópodes/toxicidade , Himenópteros/química , Animais , Venenos de Artrópodes/farmacologia , Proteínas de Insetos/química , Proteínas de Insetos/farmacologia , Proteínas de Insetos/toxicidade , Peptídeos/química , Peptídeos/farmacologia , Peptídeos/toxicidadeRESUMO
Dermal contact with Lepidoptera specimens at their larval stage (caterpillar) may cause systemic and/or local envenomation. There are multiple venomous species of them in Argentina, but their overall venom composition is poorly known. Lately, several cases of envenomation have been reported in the Misiones province, Northeastern Argentina. Thus, this work aimed to compare the protein composition, and the enzymatic properties of bristle extracts from caterpillars belonging to the families Megalopygidae (Podalia ca. fuscescens) and Saturniidae (Leucanella memusae and Lonomia obliqua) - the most common causative agents of accidents in Misiones -, and additionally to test their cross-reactivity with the L. obliqua antivenom produced in Brazil. Saturniidae venoms exhibited striking similarity in both their electrophoretic protein profile, and antigenic cross-reactivity. All venoms degraded azocasein - with the highest proteolytic activity observed in the P. ca. fuscescens bristle extract -, and hyaluronic acid, but the latter at low levels. Lonomia obliqua venom exhibited the highest level of phospholipase A2 activity. Bristle extracts from P. ca. fuscescens and L. obliqua both degraded human fibrin(ogen) and shortened the clotting time triggered by calcium, while L. memusae venom inhibited plasma coagulation. Proteins related to the coagulation disturbance were identified by mass spectrometry in all samples. Altogether, our findings show for the first time a comparative biotoxinological analysis of three genera of caterpillars with medical relevance. Moreover, this study provides relevant information about the pathophysiological mechanisms whereby these caterpillar bristle extracts can induce toxicity on human beings, and gives insight into future directions for research on them.
Assuntos
Venenos de Artrópodes/toxicidade , Mordeduras e Picadas , Mariposas/fisiologia , Animais , Argentina , Proteínas de Insetos/fisiologia , Proteínas de Insetos/toxicidade , Larva/fisiologia , ProteômicaRESUMO
Mature Ts1, the main neurotoxin from Tityus serrulatus venom, has its C-terminal Cys amidated, while the isolated isoform of Ts1, named Ts1-G, keeps the non-amidated Gly residue at the C-terminal region, allowing the study of the comparative functional importance of amidation at the C-terminal between these two native toxins. Voltage dependent sodium current measurements showed that the affinity of Ts1-G for sodium channels is smaller than that of the mature Ts1, confirming the important role played by the C-terminal amidation in determining Ts1 activity.
Assuntos
Proteínas de Artrópodes/química , Proteínas de Insetos/química , Neurotoxinas/química , Venenos de Escorpião/química , Sequência de Aminoácidos , Animais , Proteínas de Artrópodes/isolamento & purificação , Proteínas de Artrópodes/toxicidade , Glicemia/efeitos dos fármacos , Fracionamento Químico , Proteínas de Insetos/isolamento & purificação , Proteínas de Insetos/toxicidade , Masculino , Camundongos Endogâmicos , Dados de Sequência Molecular , Neurotoxinas/isolamento & purificação , Neurotoxinas/toxicidade , Isoformas de Proteínas/química , Isoformas de Proteínas/isolamento & purificação , Isoformas de Proteínas/toxicidade , Venenos de Escorpião/isolamento & purificação , Venenos de Escorpião/toxicidade , Escorpiões , Alinhamento de SequênciaRESUMO
Chagasin may be considered a potential plant-incorporated protectant (PIP) protein due to its deleterious effects on insect pests. However, extensive safety studies with PIP's are necessary before introducing them into the target plant. Thus, a short-term feeding trial in rats with high doses of r-chagasin was conducted to provide evidences about its safety. Three test diets containing casein + r-chagasin (0.25, 0.5 and 1% of total protein) were offered to rats (10 days). The test diets did not show adverse effects upon the development, organ weight, hematological parameters and serum protein profiles of rats, providing preliminary information on the safety of r-chagasin.
Assuntos
Ração Animal/toxicidade , Proteínas de Insetos/toxicidade , Tamanho do Órgão/efeitos dos fármacos , Animais , Proteínas de Insetos/administração & dosagem , Masculino , Modelos Animais , Controle Biológico de Vetores , Ratos , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/toxicidade , Testes de Toxicidade/métodos , Aumento de PesoRESUMO
Brown spider venom phospholipase-D belongs to a family of toxins characterized as potent bioactive agents. These toxins have been involved in numerous aspects of cell pathophysiology including inflammatory response, platelet aggregation, endothelial cell hyperactivation, renal disorders, and hemolysis. The molecular mechanism by which these toxins cause hemolysis is under investigation; literature data have suggested that enzyme catalysis is necessary for the biological activities triggered by the toxin. However, the way by which phospholipase-D activity is directly related with human hemolysis has not been determined. To evaluate how brown spider venom phospholipase-D activity causes hemolysis, we examined the impact of recombinant phospholipase-D on human red blood cells. Using six different purified recombinant phospholipase-D molecules obtained from a cDNA venom gland library, we demonstrated that there is a correlation of hemolytic effect and phospholipase-D activity. Studying recombinant phospholipase-D, a potent hemolytic and phospholipase-D recombinant toxin (LiRecDT1), we determined that the toxin degrades synthetic sphingomyelin (SM), lysophosphatidylcholine (LPC), and lyso-platelet-activating factor. Additionally, we determined that the toxin degrades phospholipids in a detergent extract of human erythrocytes, as well as phospholipids from ghosts of human red blood cells. The products of the degradation of synthetic SM and LPC following recombinant phospholipase-D treatments caused hemolysis of human erythrocytes. This hemolysis, dependent on products of metabolism of phospholipids, is also dependent on calcium ion concentration because the percentage of hemolysis increased with an increase in the dose of calcium in the medium. Recombinant phospholipase-D treatment of human erythrocytes stimulated an influx of calcium into the cells that was detected by a calcium-sensitive fluorescent probe (Fluo-4). This calcium influx was shown to be channel-mediated rather than leak-promoted because the influx was inhibited by L-type calcium channel inhibitors but not by a T-type calcium channel blocker, sodium channel inhibitor or a specific inhibitor of calcium activated potassium channels. Finally, this inhibition of hemolysis following recombinant phospholipase-D treatment occurred in a concentration-dependent manner in the presence of L-type calcium channel blockers such as nifedipine and verapamil. The data provided herein, suggest that the brown spider venom phospholipase-D-induced hemolysis of human erythrocytes is dependent on the metabolism of membrane phospholipids, such as SM and LPC, generating bioactive products that stimulate a calcium influx into red blood cells mediated by the L-type channel.