Nesting biology of the potter wasp Rhynchium brunneum brunneum (Fabricius, 1793) (Hymenoptera: Vespidae: Eumeninae) in North Vietnam

Rhynchium brunneum brunneum (Fabricius, 1793) is a common species using trap nests in North Vietnam. The females chose the nest traps with diameters ranging from 5.5 to 17 mm. Nests consisted of a linear series of one to eleven brood cells separated by mud partitions. Brood cells were provisioned with caterpillars, and eggs were attached to the ceiling of the cells by a thin filament. The life history and sex ratio data of this species were recorded from April to early November. Its sex ratio is strongly male-biased, being multivoltine, likely with four generations per year, the last one overwintering in the prepupal stage. Nesting activity of the species was described with major activities such as nesting site selection, oviposition, prey collecting, and applying cell material. Only 53.3% of the provisioned cells were successful; the others were damaged by six parasitoid species or died during development for unknown reasons.     

Isolation, partial purification and pharmacodynamics of a slow contractile substance in the venom sac extract of the wasp Vespa cincta Fabr

The venom of V. cincta contains acetylcholine (ACh), histamine and 5-hydroxytryptamine (5-HT). Blockers of these agonists did not block completely the hypotensive and smooth muscle contractile activity of venom. On smooth muscle, there was a residual slow contraction. The active substance which produced this slow contraction was separated by solvent extraction, gel filtration and TLC. The purified material (which has been provisionally designated "Vecikinin") lowered cat, rat and guinea pig blood pressure, increased amplitude of cardiac contraction, and increased capillary permeability. Vecikinin contracted several smooth muscle preparations (rat uterus, rat ascending colon, guinea pig ileum, guinea pig colon and rat ileum), while relaxing rat duodenum. Its contractile activity was not lost on boiling, but acid or alkali-boiling reduced its contractile activity. It was inactivated on incubation with chymotrypsin and carboxypeptidase but not with trypsin, pepsin or leucine aminopeptidase. It is a peptide, appears to be of low molecular weight, and could be distinguished from substance P, angiotensin, bradykinin and hornet or wasp kinin.     

Insensitivity of the spider heart to solitary wasp venom

• 1.1. The heart and associated tissues of spiders that had been stung by a mud-dauber wasp were examined for responses to the toxin. Microelectrode recordings of myocardial cell membrane depolarizations were obtained from spontaneously beating hearts in situ. Transmission electron microscopic examination was made of the cardiac ganglion, myocardium and hemocytes.
• 2.2. The myocardial cell depolarizations in paralyzed and unparalyzed spiders were 20–40 mV in amplitude and 300–500 msec in duration. The depolarizations did not display an overshoot, and individual excitatory synaptic potentials were seen in the responses. Therefore, the normal electrical events in the heartbeat, which is neurogenic, were not interrupted by the toxin.
• 3.3. No alteration in the ultrastructure of the cardiac ganglion, neuromuscular synapses, myocardial cells or hemocytes was apparent in the material obtained from paralyzed spiders.

     

Males of a solitary wasp possess a postpharyngeal gland

The postpharyngeal gland has long been thought to occur only in ants. Here we characterize, by use of light and electron microscopy as well as 3D reconstruction based on nuclear magnetic resonance (NMR) imaging data, a large cephalic gland reservoir of males of a solitary digger wasp, the European beewolf, Philanthus triangulum. Several lines of evidence suggest that this reservoir is a postpharyngeal gland. The gland reservoir originates from the posterior part of the pharynx and consists of two pairs of unbranched tubular structures that occupy a large portion of the head capsule. Its wall is composed of a unicellular epithelium that is lined by a cuticle. The gland contains a blend of hydrocarbons and compounds with functional groups, and we show that the hydrocarbon fraction of the pheromone is congruent with the hydrocarbons on the cuticle. We discuss the implications of our findings for the evolution of the postpharyngeal gland in ants.     

Molecular components and toxicity of the venom of the solitary wasp, Anoplius samariensis

The solitary spider wasp, Anoplius samariensis, is known to exhibit a unique long-term, non-lethal paralysis in spiders that it uses as a food source for its larvae. However, neither detailed venom components nor paralytic compounds have ever been characterized. In this study, we examined the components in the low molecular weight fraction of the venom and the paralytic activity of the high molecular weight fraction. The major low molecular weight components of the venom were identified as gamma-aminobutyric acid and glutamic acid by micro-liquid chromatography/electrospray ionization mass spectrometry and nuclear magnetic resonance spectrometry analysis. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis and mass analysis revealed that the A. samariensis venom contained the various proteins with weights of 4-100 kDa. A biological assay using Joro spiders (Nephila clavata) clearly showed that the high molecular weight fraction of the venom prepared by ultrafiltration exerted as potent non-lethal long-term paralysis as the whole venom, whereas the low molecular weight fraction was devoid of any paralytic activity. These results indicated that several venomous proteins in the high molecular weight fraction are responsible for the paralytic activity. Furthermore, we determined the primary structure of one component designated As-fr-19, which was a novel multiple-cysteine peptide with high sequence similarity to several sea anemone and snake toxins including dendrotoxins, rather than any insect toxic peptides identified so far. Taken together, our data showed the unprecedented molecular and toxicological profiles of wasp venoms.     

Proteomic analysis of the venom of the social wasp Apoica pallens (Hymenoptera: Vespidae)

Wasps are a diverse group of insects that possess a sting apparatus associated with a venom gland, which is used for predation and colony defense. The biochemistry of Hymenoptera venom has been evaluated in relation to allergy and immunology, and proteomics has been shown to be a powerful tool for the identification of compounds with pharmacological potential. Data on wasps venom the of genus Apoica are scarce, so the objective of the present work was to identify the venom proteins of the eusocial wasp Apoica pallens, as a first step towards further investigation of applied uses of the venom and its protein constituents. The venom proteins were separated by two-dimensional gel electrophoresis, followed by MALDI-TOF/TOF mass spectrometry. A total of 259 spots were detected, with molecular weights from 4.9 to 141 kDa. Thirty of these proteins were identified and classified into eight functional categories: allergen, enzyme, metabolism, structural, environmental response, proteoglycan, active in DNA and RNA, and unknown function. Due to the few available proteomic data for wasp venom, many proteins could not be identified, which makes studies with proteomic analysis of Hymenoptera venom even more important.     

Profiling the peptidome of the venom from the social wasp Agelaia pallipes pallipes

The wasp Agelaia pallipes pallipes is one of the most aggressive species from the neotropical region, causing many stinging accidents every year, characterized by severe envenoming reactions. The identification of peptides is important for understanding the envenoming process; however, the tiny amount of venom produced by these insects makes this task a challenge, using classical analytical approaches. Thus, the venom was previously fractionated, and the sequences were obtained through the use of electrospray ionization with a tridimensional ion-trap and time-of-flight mass analysis under CID conditions. This approach permitted the sequence assignment of nine peptides. The presence of type -d and -w ions generated from the fragmentation of the side chains was used to resolve I/L ambiguity. The distinction between K and Q residues was achieved through esterification of the α- and ε-amino groups in the peptides, followed by mass spectrometry analysis. Six of these peptides were short, linear and polycationic, while the three other peptides presented a single disulfide bridge. The use of reduction and alkylation protocols, followed by ESI-IT-TOF/MS analysis under CID conditions, permitted easy sequencing of the three peptides presenting this post-translational modification. These peptides presented activity related to mast cell degranulation, hemolysis, or even the chemotaxis of leukocytes.     

Anoplin, a novel antimicrobial peptide from the venom of the solitary wasp Anoplius samariensis.

A novel antimicrobial peptide, anoplin, was purified from the venom of the solitary wasp Anoplius samariensis. The sequence was mostly analyzed by mass spectrometry, which was corroborated by solid-phase synthesis. Anoplin, composed of 10 amino acid residues, Gly-Leu-Leu-Lys-Arg-Ile-Lys-Thr-Leu-Leu-NH2, has a high homology to crabrolin and mastoparan-X, the mast cell degranulating peptides from social wasp venoms, and, therefore, can be predicted to adopt an amphipathic alpha-helix secondary structure. In fact, the circular dichroism (CD) spectra of anoplin in the presence of trifluoroethanol or sodium dodecyl sulfate showed a high content, up to 55%, of the alpha-helical conformation. A modeling study of anoplin based on its homology to mastoparan-X supported the CD results. Biological evaluation using the synthetic peptide revealed that this peptide exhibited potent activity in stimulating degranulation from rat peritoneal mast cells and broad-spectrum antimicrobial activity against both Gram-positive and Gram-negative bacteria. Therefore, this is the first antimicrobial component to be found in the solitary wasp venom and it may play a key role in preventing potential infection by microorganisms during prey consumption by their larvae. Moreover, this peptide is the smallest among the linear alpha-helical antimicrobial peptides hitherto found in nature, which is advantageous for chemical manipulation and medical application.     

Eumenitin, a novel antimicrobial peptide from the venom of the solitary eumenine wasp Eumenes rubronotatus

A novel antimicrobial peptide, eumenitin, was isolated from the venom of the solitary eumenine wasp Eumenes rubronotatus. The sequence of eumenitin, Leu-Asn-Leu-Lys-Gly-Ile-Phe-Lys-Lys-Val-Ala-Ser-Leu-Leu-Thr, was mostly analyzed by mass spectrometry together with Edman degradation, and corroborated by solid-phase synthesis. This peptide has characteristic features of cationic linear alpha-helical antimicrobial peptides, and therefore, can be predicted to adopt an amphipathic alpha-helix secondary structure. In fact, the CD spectra of eumenitin in the presence of TFE or SDS showed a high content of alpha-helical conformation. Eumenitin exhibited inhibitory activity against both Gram-positive and Gram-negative bacteria, and moderately stimulated degranulation from the rat peritoneal mast cells and the RBL-2H3 cells, but showed no hemolytic activity against human erythrocytes. This antimicrobial peptide in the eumenine wasp venom may play a role in preventing potential infection by microorganisms during prey consumption by their larvae.     

松树蜂毒腺转录组分析

【目的】构建入侵种松树蜂Sirex noctilio毒腺转录组数据库,筛选并分析松树蜂毒腺基因数据。【方法】采用新一代高通量测序平台Illumina HiSeq^TM 4000对松树蜂雌成虫毒腺进行转录组测序、数据组装和生物信息学分析。【结果】共获得12.7 Gb松树蜂雌成虫毒腺有效转录组数据,并组装到37 098条unigenes,平均长度968 bp,N50长度为2 364 bp。将所得的unigenes数据使用BlastX与各大数据库比对,共注释到13 515条unigenes,并且在NR数据库中注释的unigenes最多,共11 108条(占总数的29.94%),其中相似基因占比最高的物种为丽蝇蛹集金小蜂Nasonia vitripennis,达815条(占总数的7.29%)。在GO数据库中注释到5 726条unigenes,根据功能被分为生物学进程、细胞组分和分子功能3大类63个亚类。KEGG代谢通路分析表明,7 602条unigenes注释到357个代谢通路。根据基因注释信息进一步筛选到43条嗅觉相关基因,包括嗅觉受体(odorant receptor, Or)基因25条、化学感受蛋白(chemosensory protein, CSP)基因10条、离子型受体(ionotropic receptor, IR)基因5条和气味结合蛋白(odorant binding protein, OBP)基因3条。此外,还筛选出11条漆酶基因,包括漆酶1(laccase1, LAC1)基因5条、漆酶2(laccase2, LAC2)基因4条、漆酶4(laccase4, LAC4)基因1条和漆酶9(laccase9, LAC9)基因1条,且其中1条LAC2基因在所有被注释的基因中表达量最高(FPKM值=21 126)。【结论】本研究获得的松树蜂毒腺转录组数据为松树蜂毒液组分的鉴定和生物学功能的研究奠定了一定的理论基础。     

Partial venom gland transcriptome of a Drosophila parasitoid wasp, Leptopilina heterotoma, reveals novel and shared bioactive profiles with stinging Hymenoptera

Analysis of natural host-parasite relationships reveals the evolutionary forces that shape the delicate and unique specificity characteristic of such interactions. The accessory long gland-reservoir complex of the wasp Leptopilina heterotoma (Figitidae) produces venom with virus-like particles. Upon delivery, venom components delay host larval development and completely block host immune responses. The host range of this Drosophila endoparasitoid notably includes the highly-studied model organism, Drosophila melanogaster. Categorization of 827 unigenes, using similarity as an indicator of putative homology, reveals that approximately 25% are novel or classified as hypothetical proteins. Most of the remaining unigenes are related to processes involved in signaling, cell cycle, and cell physiology including detoxification, protein biogenesis, and hormone production. Analysis of L. heterotoma's predicted venom gland proteins demonstrates conservation among endo- and ectoparasitoids within the Apocrita (e.g., this wasp and the jewel wasp Nasonia vitripennis) and stinging aculeates (e.g., the honey bee and ants). Enzyme and KEGG pathway profiling predicts that kinases, esterases, and hydrolases may contribute to venom activity in this unique wasp. To our knowledge, this investigation is among the first functional genomic studies for a natural parasitic wasp of Drosophila. Our findings will help explain how L. heterotoma shuts down its hosts' immunity and shed light on the molecular basis of a natural arms race between these insects.     

Decoralin, a novel linear cationic alpha-helical peptide from the venom of the solitary eumenine wasp Oreumenes decoratus

A novel peptide, decoralin, was isolated from the venom of the solitary eumenine wasp Oreumenes decoratus. Its sequence, Ser-Leu-Leu-Ser-Leu-Ile-Arg-Lys-Leu-Ile-Thr, was determined by Edman degradation and corroborated by solid-phase synthesis. This sequence has the characteristic features of linear cationic alpha-helical peptides; rich in hydrophobic and basic amino acids with no disulfide bond, and accordingly, it can be predicted to adopt an amphipathic alpha-helix secondary structure. In fact, the CD spectra of decoralin in the presence of TFE or SDS showed a high alpha-helical conformation content. In a biological evaluation, decoralin exhibited a significant broad-spectrum antimicrobial activity, and moderate mast cell degranulation and leishmanicidal activities, but showed virtually no hemolytic activity. A synthetic analog with C-terminal amidation showed a much more potent activity in all the biological assays.