Isolation and molecular cloning of venom peptides from Orancistrocerus drewseni (Hymenoptera: Eumenidae)

Characterization of the Hemolytic Activity of Mastoparan Family Peptides from Wasp Venoms

Biologically active peptides have attracted increasing attention in research on the development of new drugs. Mastoparans, a group of wasp venom linear cationic α-helical peptides, have a variety of biological effects, including mast cell degranulation, activation of protein G, and antimicrobial and anticancer activities. However, the potential hemolytic activity of cationic α-helical peptides greatly limits the clinical applications of mastoparans. Here, we systematically and comprehensively studied the hemolytic activity of mastoparans based on our wasp venom mastoparan family peptide library. The results showed that among 55 mastoparans, 18 had strong hemolytic activity (EC50 ≤ 100 μM), 14 had modest hemolytic activity (100 μM < EC50 ≤ 400 μM) and 23 had little hemolytic activity (EC50 > 400 μM), suggesting functional variation in the molecular diversity of mastoparan family peptides from wasp venom. Based on these data, structure-function relationships were further explored, and, hydrophobicity, but not net charge and amphiphilicity, was found to play a critical role in the hemolytic activity of mastoparans. Combining the reported antimicrobial activity with the present hemolytic activity data, we found that four mastoparan peptides, Parapolybia-MP, Mastoparan-like peptide 12b, Dominulin A and Dominulin B, have promise for applications because of their high antimicrobial activity (MIC ≤ 10 μM) and low hemolytic activity (EC50 ≥ 400 μM). Our research not only identified new leads for the antimicrobial application of mastoparans but also provided a large chemical space to support the molecular design and optimization of mastoparan family peptides with low hemolytic activity regardless of net charge or amphiphilicity.

Exploring the therapeutic potential of an antinociceptive and anti-inflammatory peptide from wasp venom

Animal venoms are rich sources of neuroactive compounds, including anti-inflammatory, antiepileptic, and antinociceptive molecules. Our study identified a protonectin peptide from the wasp Parachartergus fraternus' venom using mass spectrometry and cDNA library construction. Using this peptide as a template, we designed a new peptide, protonectin-F, which exhibited higher antinociceptive activity and less motor impairment compared to protonectin. In drug interaction experiments with naloxone and AM251, Protonectin-F's activity was decreased by opioid and cannabinoid antagonism, two critical antinociception pathways. Further experiments revealed that this effect is most likely not induced by direct action on receptors but by activation of the descending pain control pathway. We noted that protonectin-F induced less tolerance in mice after repeated administration than morphine. Protonectin-F was also able to decrease TNF-α production in vitro and modulate the inflammatory response, which can further contribute to its antinociceptive activity. These findings suggest that protonectin-F may be a potential molecule for developing drugs to treat pain disorders with fewer adverse effects. Our results reinforce the biotechnological importance of animal venom for developing new molecules of clinical interest.

Truncated analog Brevinin2-CE-N26V5K: Revelation the Augmentation of Antimicrobial Activity

Brevinin2-CE (B2CE), a natural peptide containing 37 amino acids, was first isolated from the skin secretions of the Chinese forest frog Rana chensinensis. B2CE shows good antibacterial activity. In this study, a series of B2CE analogs with differences in cationicity, α-helicity, hydrophobicity and amphipathic properties were designed through chain-length deletion and amino acid substitution. The most potent, nontoxic analog, B2CE-N26V5K, was identified by examination of its antibacterial activity, hemolytic activity, and stability under physiological conditions. The increased cationicity, hydrophobicity and more obvious hydrophilic and hydrophobic surface of B2CE-N26-N16WA18KG23K did not improve the antibacterial activity but increased the hemolytic activity of this modified peptide. The helicity might promote antibacterial activity for brevinin-2 peptides, as the 15-aa analogs with lower helicity show decreased potency against different test bacteria (approximately 2- to 72-fold) compared to B2CE-N26V5K. Additionally, the results indicated that the "Rana box" does not affect the antimicrobial activity of brevinin-2 peptides, as B2CE, B2CE-nonDS and B2CE-C31-37 S have similar strong inhibitory effects on both gram-positive and gram-negative bacteria. However, the "Rana box" does affect the hemolytic activity, as the HC₅₀ values of the 3 peptides range from 25 ~ 130 µM. Furthermore, B2CE-N26V5K caused obvious morphological alterations of the bacterial surfaces, as shown by atomic force microscopy. Additionally, B2CE-N26V5K exhibited strong membrane-disrupting activity when examined using the LIVE/DEAD Bac Light Bacterial Viability Kit. Thus, the antibacterial effect of B2CE-N26V5K on gram-negative and gram-positive bacteria may be caused by cell membrane attack. In conclusion, the excellent candidate B2CE-N26V5K was obtained and has application prospects as a novel anti-infective agent.

Mastoparans: A Group of Multifunctional α-Helical Peptides With Promising Therapeutic Properties

Biologically active peptides have been attracting increasing attention, whether to improve the understanding of their mechanisms of action or in the search for new therapeutic drugs. Wasp venoms have been explored as a remarkable source for these molecules. In this review, the main findings on the group of wasp linear cationic α-helical peptides called mastoparans were discussed. These compounds have a wide variety of biological effects, including mast cell degranulation, activation of protein G, phospholipase A₂, C, and D activation, serotonin and insulin release, and antimicrobial, hemolytic, and anticancer activities, which could lead to the development of new therapeutic agents.

Profiling hymenopteran venom toxins: Protein families, structural landscape, biological activities, and pharmacological benefits

Hymenopterans are an untapped source of venom secretions. Their recent proteo-transcriptomic studies have revealed an extraordinary pool of toxins that participate in various biological processes, including pain, paralysis, allergic reactions, and antimicrobial activities. Comprehensive and clade-specific campaigns to collect hymenopteran venoms are therefore needed. We consider that data-driven bioprospecting may help prioritise sampling and alleviate associated costs. This work established the current protein landscape from hymenopteran venoms to evaluate possible sample bias by studying their origins, sequence diversity, known structures, and biological functions. We collected all 282 reported hymenopteran toxins (peptides and proteins) from the UniProt database that we clustered into 21 protein families from the three studied clades - wasps, bees, and ants. We identified 119 biological targets of hymenopteran toxins ranging from pathogen membranes to eukaryotic proteases, ion channels and protein receptors. Our systematic study further extended to hymenopteran toxins' therapeutic and biotechnological values, where we revealed promising applications in crop pests, human infections, autoimmune diseases, and neurodegenerative disorders.

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The hymenopteran toxin diversity includes 21 protein families from 81 species.

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Some toxins are shared across wasps, bees and ants, others are clade-specific.

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Their venoms contain membrane-active peptides, neurotoxins, allergens and enzymes.

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Hymenopteran toxins have been tested against a total of 119 biological targets.

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Hymenopteran toxins were predominantly evaluated as anti-infective agents.

Isolation and characterization of FMRFamide-like peptides in the venoms of solitary sphecid wasps

Purification of small peptide components in the venoms of the solitary sphecid wasps, Sphex argentatus argentatus and Isodontia harmandi, led to the isolation of several major peptides. Analysis of MS/MS spectra by MALDI-TOF/TOF revealed the sequence of a new peptide Sa112 (EDVDHVFLRF-NH₂), which is structurally very similar to leucomyosupressin (pQDVDHVFLRF-NH₂) and SchistoFLRFamide (PDVDHVFLRF-NH₂), the FMRFamide-like peptides from cockroach and locust, respectively. Indeed, this new peptide, like SchistoFLRFamide, inhibited the frequency and amplitude of spontaneous contractions of the locust oviduct in a dose-dependent manner. A non-amidated peptide Sa12b (EDVDHVFLRF) was also isolated, but this peptide had no effect on spontaneous locust oviduct contraction. This is the first example of a FMRF-like peptide to be found in solitary wasp venom. Additionally, a truncated form of the myosuppressins, which has previously been synthesized and tested for biological activity, DVDHVFLRF-NH₂ (Sh5b), was found for the first time as a natural product. Four other novel peptides were isolated and characterized as Sa81 (EDDLEDFNPTVS), Sa10 (EDDLEDFNPTIA), Sh41 (DDLSDFNPKV), and Sh42 (EDDLSDFNPKV). They are structurally related to each other, having a high content of acidic amino acids, but no structural similarity to any known peptides. Ion channel associated activities of Sh41 and Sh42 were tested, but did not show any activity for Na⁺, K⁺, Ca²⁺ channels.

New bioactive peptides from the venom gland of a social hornet Vespa velutina

Bacterial resistance to drugs is a global problem requiring the urgent development of new antibiotics. Antimicrobial peptides (AMPs) are excellent candidates for the design of novel antibiotics to combat microbial resistance. In this research, we identified four new peptides (U-VVTX-Vp1a, U-VVTX-Vp1b, U-VVTX-Vp2a, and U-VVTX-Vp2b, respectively) from the venom of Vespa velutina, and tested their antimicrobial, antioxidant, and hemolytic effects. All four peptides showed scavenging ability against DPPH, ABTS⁺, and •OH free radicals. Of note, Vp1b strongly inhibited the growth of Staphylococcus aureus and Escherichia coli bacteria at concentrations of 60 and 120 μM. Due to their low hemolytic activity, all four peptides could be utilized in the development of new antioxidants and as candidates for the design of novel antimicrobial agents.

Wasp Venom Biochemical Components and Their Potential in Biological Applications and Nanotechnological Interventions

Wasps, members of the order Hymenoptera, are distributed in different parts of the world, including Brazil, Thailand, Japan, Korea, and Argentina. The lifestyles of the wasps are solitary and social. Social wasps use venom as a defensive measure to protect their colonies, whereas solitary wasps use their venom to capture prey. Chemically, wasp venom possesses a wide variety of enzymes, proteins, peptides, volatile compounds, and bioactive constituents, which include phospholipase A2, antigen 5, mastoparan, and decoralin. The bioactive constituents have anticancer, antimicrobial, and anti-inflammatory effects. However, the limited quantities of wasp venom and the scarcity of advanced strategies for the synthesis of wasp venom’s bioactive compounds remain a challenge facing the effective usage of wasp venom. Solid-phase peptide synthesis is currently used to prepare wasp venom peptides and their analogs such as mastoparan, anoplin, decoralin, polybia-CP, and polydim-I. The goal of the current review is to highlight the medicinal value of the wasp venom compounds, as well as limitations and possibilities. Wasp venom could be a potential and novel natural source to develop innovative pharmaceuticals and new agents for drug discovery.

Chemical and Biological Characteristics of Antimicrobial α-Helical Peptides Found in Solitary Wasp Venoms and Their Interactions with Model Membranes

Solitary wasps use their stinging venoms for paralyzing insect or spider prey and feeding them to their larvae. We have surveyed bioactive substances in solitary wasp venoms, and found antimicrobial peptides together with some other bioactive peptides. Eumenine mastoparan-AF (EMP-AF) was the first to be found from the venom of the solitary eumenine wasp Anterhynchium flavomarginatum micado, showing antimicrobial, histamine-releasing, and hemolytic activities, and adopting an α-helical secondary structure under appropriate conditions. Further survey of solitary wasp venom components revealed that eumenine wasp venoms contained such antimicrobial α-helical peptides as the major peptide component. This review summarizes the results obtained from the studies of these peptides in solitary wasp venoms and some analogs from the viewpoint of (1) chemical and biological characterization; (2) physicochemical properties and secondary structure; and (3) channel-like pore-forming properties.

New Mastoparan Peptides in the Venom of the Solitary Eumenine Wasp Eumenes micado

Comprehensive LC-MS and MS/MS analysis of the crude venom extract from the solitary eumenine wasp Eumenes micado revealed the component profile of this venom mostly consisted of small peptides. The major peptide components, eumenine mastoparan-EM1 (EMP-EM1: LKLMGIVKKVLGAL-NH₂) and eumenine mastoparan-EM2 (EMP-EM2: LKLLGIVKKVLGAI-NH₂), were purified and characterized by the conventional method. The sequences of these new peptides are homologous to mastoparans, the mast cell degranulating peptides from social wasp venoms; they are 14 amino acid residues in length, rich in hydrophobic and basic amino acids, and C-terminal amidated. Accordingly, these new peptides can belong to mastoparan peptides (in other words, linear cationic α-helical peptides). Indeed, the CD spectra of these new peptides showed predominantly α-helix conformation in TFE and SDS. In biological evaluation, both peptides exhibited potent antibacterial activity, moderate degranulation activity from rat peritoneal mast cells, and significant leishmanicidal activity, while they showed virtually no hemolytic activity on human or mouse erythrocytes. These results indicated that EMP-EM peptides rather strongly associated with bacterial cell membranes rather than mammalian cell membranes.

Evaluation of the bioactivity of a mastoparan peptide from wasp venom and of its analogues designed through targeted engineering

Mastoparan is a typical cationic and amphipathic tetradecapeptide found in wasp venom and exhibits potent biological activities. Yet, compared with other insect-derived peptides, such as melittin from the bee venom, this family have been underrated. Herein, we evaluated the biological activities of mastoparan-C (MP-C), which was identified from the venom of the European Hornet (Vespa crabro), and rationally designed two analogues (a skeleton-based cyclization by two cysteine residues and an N-terminal extension via tat-linked) for enhancing the stability of the biological activity and membrane permeability, respectively. Three peptides possessed broadly efficacious inhibiting capacities towards common pathogens, resistant strains, as well as microbial biofilm. Although, cyclized MP-C showed longer half-life time than the parent peptide, the lower potency of antimicrobial activity and higher degree of haemolysis were observed. The tat-linked MP-C exhibited more potent anticancer activity than the parent peptide, but it also loses the specificity. The study revealed that MP-C is good candidate for developing antimicrobial agents and the targeted-design could improve the stability and transmembrane delivery, but more investigation would be needed to adjust the side effects brought from the design.

Protection efficacy of the Brucella abortus ghost vaccine candidate lysed by the N-terminal 24-amino acid fragment (GI24) of the 36-amino acid peptide PMAP-36 (porcine myeloid antimicrobial peptide 36) in murine models

Brucella abortus cells were lysed by the N-terminal 24-amino acid fragment (GI24) of the 36-amino acid peptide PMAP-36 (porcine myeloid antimicrobial peptide 36). Next, the protection efficacy of the lysed fragment as a vaccine candidate was evaluated. Group A mice were immunized with sterile PBS, group B mice were intraperitoneally (ip) immunized with 3 × 10⁸ colony-forming units (CFUs) of B. abortus strain RB51, group C mice were immunized ip with 3 × 10⁸ cells of the B. abortus vaccine candidate, and group D mice were orally immunized with 3 × 10⁹ cells of the B. abortus vaccine candidate. Brucella lipopolysaccharide (LPS)-specific serum IgG titers were considerably higher in groups C and D than in group A. The levels of interleukin (IL)-4, IL-10, tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) were significantly higher in groups B–D than in group A. After an ip challenge with B. abortus 544, only group C mice showed a significant level of protection as compared to group A. Overall, these results show that ip immunization with a vaccine candidate lysed by GI24 can effectively protect mice from systemic infection with virulent B. abortus.

Peptide Toxins in Solitary Wasp Venoms

Solitary wasps paralyze insects or spiders with stinging venom and feed the paralyzed preys to their larva. Accordingly, the venoms should contain a variety of constituents acting on nervous systems. However, only a few solitary wasp venoms have been chemically studied despite thousands of species inhabiting the planet. We have surveyed bioactive substances in solitary wasp venoms found in Japan and discovered a variety of novel bioactive peptides. Pompilidotoxins (PMTXs), in the venoms of the pompilid wasps Anoplius samariensis and Batozonellus maculifrons, are small peptides consisting of 13 amino acids without a disulfide bond. PMTXs slowed Na⁺ channel inactivation, in particular against neuronal type Na⁺ channels, and were rather selective to the Nav1.6 channel. Mastoparan-like cytolytic and antimicrobial peptides are the major components of eumenine wasp venoms. They are rich in hydrophobic and basic amino acids, adopting a α-helical secondary structure, and showing mast cell degranulating, antimicrobial and hemolytic activities. The venom of the spider wasp Cyphononyx fulvognathus contained four bradykinin-related peptides. They are hyperalgesic and, dependent on the structure, differently associated with B₁ or B₂ receptors. Further survey led to the isolation of leucomyosuppressin-like FMRFamide peptides from the venoms of the digger wasps Sphex argentatus and Isodontia harmandi. These results of peptide toxins in solitary wasp venoms from our studies are summarized.

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.

Integrated analysis of the ecotoxicological and genotoxic effects of the antimicrobial peptide melittin on Daphnia magna and Pseudokirchneriella subcapitata

Melittin is a major constituent of the bee venom of Apis mellifera with a broad spectrum of activities. Melittin therapeutical potential is subject to its toxicity and the assessment of ecotoxicity and genotoxicity is of particular interest for therapeutic use. Here we analyzed the biological effects of melittin on two aquatic species, which are representative of two different levels of the aquatic trophic chain: the invertebrate Daphnia magna and the unicellular microalgae Pseudokirchneriella subcapitata. The attention was focused on the determination of: i) ecotoxicity; ii) genotoxicity; iii) antigenotoxicity. Our main finding is that melittin is detrimental to D. magna reproduction and its sub-lethal concentrations create an accumulation dependent on exposition times and a negative effect on DNA. We also observed that melittin significantly delayed time to first eggs. Moreover, results showed that melittin exerted its toxic and genotoxic effects in both species, being a bit more aggressive towards P. subcapitata.

Antimicrobial activity and membrane-active mechanism of tryptophan zipper-like β-hairpin antimicrobial peptides

Antimicrobial peptides (AMPs) with amphipathic β-hairpin structures have been demonstrated to possess potent antimicrobial activities and great cell selectivities. However, our understanding of β-hairpin antimicrobial peptides lags behind that of α-helices, mainly because it is difficult for short peptides to form robust β-hairpin structures. Tryptophan zipper (trpzip) peptides are among the most stable β-hairpin peptides known to fold spontaneously without requiring covalent disulfide constraint or metal binding. To develop model β-hairpin AMPs with small size and remarkable stability, a series of amphiphilic linear peptides were designed based on the trpzip motif. The sequence of designed peptides is (WK) n (D) PG(KW) n -NH2 (n = 1, 2, 3, 4, 5), and the antimicrobial activity and membrane interaction mechanism of the peptides were evaluated. The results showed that these peptides readily fold into β-hairpin structures in aqueous and membrane-mimicking environments and exhibit broad-spectrum antimicrobial activities against both gram-positive and gram-negative bacteria. The antibacterial potency of the peptides initially increased and then decreased with increasing chain length. WK3, a 14-residue peptide, displayed excellent antimicrobial activity with minimal hemolytic activity and cytotoxicity, suggesting that it possesses great cell selectivity. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), fluorescence spectroscopy, and flow cytometry indicated that representative peptides WK3 and WK4 exert their activities by permeabilizing the microbial membrane and damaging cell membrane integrity. This study reveals the application potential of the designed peptides as promising antimicrobial agents for the control of infectious diseases, and it also provides new insights into the design and optimization of highly stable β-hairpin AMPs with great antimicrobial activities and cell selectivities.

Production of antibacterial peptide from bee venom via a new strategy for heterologous expression

Honey bee is important economic insect that not only pollinates fruits and crops but also provides products with various physiological activities. Bee venom is a functional agent that is widely applied in clinical treatment and pharmacy. Secapin is one of these agents that have a significant role in therapy. The functions of secapin from the bee venom have been documented, but little information is known about its heterologous expression under natural condition. Moreover, few scholars verified experimentally the functions of secapin from bee venom in vitro. In this study, we successfully constructed a heterologous expression vector, which is different from conventional expression system. A transgenic approach was established for transformation of secapin gene from the venom of Apis mellifera carnica (Ac-sec) into the edible fungi, Coprinus cinereus. Ac-sec was encoded by a 234 bp nucleotide that contained a signal peptide domain and two potential phosphorylation sites. The sequence exhibited highly homology with various secapins characterized from honey bee and related species. Southern blot data indicated that Ac-sec was present as single or multiple copy loci in the C. cinereus genome. By co-transformation and double-layer active assay, Ac-sec was expressed successfully in C. cinereus and the antibacterial activity of the recombinants was identified, showing notable antibacterial activities on different bacteria. Although Ac-sec is from the venom of Apidae, phylogenetic analysis demonstrated that Ac-sec was more closely related to that of Vespid than to bee species from Apidae. The molecular characteristics of Ac-sec and the potential roles of small peptides in biology were discussed.

Polar characterization of antifungal peptides from APD2 Database

The increase in the number of pathogens due to fungi that are tolerant to therapies does not grow at the same speed than the advance on new antifungal drugs. In this sense, it is imperative to find anti-fungi peptides that are not detrimental to mammalian cells and have an effective toxicity to fungi. In this work, we use a method called polarity index, to identify anti-fungi peptides with an efficiency of 70 %. This method already published, initially identified selective antibacterial peptides from APD2 Database, and was characterized by developing a comprehensive analysis of the polar dynamics of a peptide from its linear sequence. Discriminating tests showed that in addition to being efficient in this identification, it was also good at rejecting other classifications of peptides found in that same database.

Antimicrobial properties and membrane-active mechanism of a potential α-helical antimicrobial derived from cathelicidin PMAP-36

Antimicrobial peptides (AMPs), which present in the non-specific immune system of organism, are amongst the most promising candidates for the development of novel antimicrobials. The modification of naturally occurring AMPs based on their residue composition and distribution is a simple and effective strategy for optimization of known AMPs. In this study, a series of truncated and residue-substituted derivatives of antimicrobial peptide PMAP-36 were designed and synthesized. The 24-residue truncated peptide, GI24, displayed antimicrobial activity comparable to the mother peptide PMAP-36 with MICs ranging from 1 to 4 µM, which is lower than the MICs of bee venom melittin. Although GI24 displayed high antimicrobial activity, its hemolytic activity was much lower than melittin, suggesting that GI24 have optimal cell selectivity. In addition, the crucial site of GI24 was identified through single site-mutation. An amino acid with high hydrophobicity at position 23 played an important role in guaranteeing the high antimicrobial activity of GI24. Then, lipid vesicles and whole bacteria were employed to investigate the membrane-active mechanisms. Membrane-simulating experiments showed that GI24 interacted strongly with negatively charged phospholipids and weakly with zwitterionic phospholipids, which corresponded well with the data of its biological activities. Membrane permeabilization and flow cytometry provide the evidence that GI24 killed microbial cells by permeabilizing the cell membrane and damaging membrane integrity. GI24 resulted in greater cell morphological changes and visible pores on cell membrane as determined using scanning electron microscopy (SEM) and transmission electron microscope (TEM). Taken together, the peptide GI24 may provide a promising antimicrobial agent for therapeutic applications against the frequently-encountered bacteria.

"It stings a bit but it cleans well": venoms of Hymenoptera and their antimicrobial potential

Venoms from Hymenoptera display a wide range of functions and biological roles. These notably include manipulation of the host, capture of prey and defense against competitors and predators thanks to endocrine and immune systems disruptors, neurotoxic, cytolytic and pain-inducing venom components. Recent works indicate that many hymenopteran species, whatever their life style, have also evolved a venom with properties which enable it to regulate microbial infections, both in stinging and stung animals. In contrast to biting insects and their salivary glands, stinging Hymenoptera seem to constitute an under-exploited ecological niche for agents of vector-borne disease. Few parasitic or mutualistic microorganisms have been reported to be hosted by venom-producing organs or to be transmitted to stung animals. This may result from the presence of potent antimicrobial molecules in venoms, histological features of venom apparatuses and selective effects of venoms on immune defenses of targeted organisms. The present paper reviews for the first time the venom antimicrobial potential of solitary and social Hymenoptera in molecular, ecological, and evolutionary perspectives.

Identification and characterization of a novel antimicrobial peptide from the venom of the ant Tetramorium bicarinatum

A novel antimicrobial peptide, named Bicarinalin, has been isolated from the venom of the ant Tetramorium bicarinatum. Its amino acid sequence has been determined by de novo sequencing using mass spectrometry and by Edman degradation. Bicarinalin contained 20 amino acid residues and was C-terminally amidated as the majority of antimicrobial peptides isolated to date from insect venoms. Interestingly, this peptide had a linear structure and exhibited no meaningful similarity with any known peptides. Antibacterial activities against Staphylococcus aureus and S. xylosus strains were evaluated using a synthetic replicate. Bicarinalin had a potent and broad antibacterial activity of the same magnitude as Melittin and other hymenopteran antimicrobial peptides such as Pilosulin or Defensin. Moreover, this antimicrobial peptide has a weak hemolytic activity compared to Melittin on erythrocytes, suggesting potential for development into an anti-infective agent for use against emerging antibiotic-resistant pathogens.

Overview on the recent study of antimicrobial peptides: origins, functions, relative mechanisms and application

Antimicrobial peptides (AMPs), which are produced by several species including insects, other animals, micro-organisms and synthesis, are a critical component of the natural defense system. With the growing problem of pathogenic organisms resistant to conventional antibiotics, especially with the emergence of NDM-1, there is increased interest in the pharmacological application of AMPs. They can protect against a broad array of infectious agents, such as bacteria, fungi, parasite, virus and cancer cells. AMPs have a very good future in the application in pharmaceuticals industry and food additive. This review focuses on the AMPs from different origins in these recent years, and discusses their various functions and relative mechanisms of action. It will provide some detailed files for clinical research of pharmaceuticals industry and food additive in application.

Venom peptides from solitary hunting wasps induce feeding disorder in lepidopteran larvae

The cell lytic activity and toxicity against lepidopteran larvae of 13 venom peptides (4 OdVPs and 9 EpVPs) from two solitary hunting wasps, Orancistrocerus drewseni and Eumenes pomiformis, were examined with mastoparan as a reference peptide. Of the 13 peptides, 7 were predicted to have α-helical structures that exhibit the typical character of amphipathic α-helical antimicrobial peptides. The remaining peptides exhibited coil structures; among these, EpVP5 possesses two Cys residues that form an internal disulfide bridge. All the helical peptides including mastoparan showed antimicrobial and insect cell lytic activities, whereas only two of them were hemolytic against human erythrocytes. The helical peptides induced a feeding disorder when injected into the vicinity of the head and thorax of Spodoptera exigua larvae, perhaps because their non-specific neurotoxic or myotoxic action induced cell lysis. At low concentrations, however, these helical peptides increased cell permeability without inducing cell lysis. These findings suggest that the helical venom peptides may function as non-specific neurotoxins or myotoxins and venom-spreading factors at low concentrations, as well as preservatives for long-term storage of the prey via antimicrobial, particularly antifungal, activities.

Identification and characterization of venom proteins of two solitary wasps, Eumenes pomiformis and Orancistrocerus drewseni

Secretory proteins were identified in the venoms of two solitary hunting wasps, Eumenes pomiformis and Orancistrocerus drewseni, by SDS-PAGE in conjunction with mass analysis. More than 30 protein bands (2-300 kDa) were detected from the crude venom of each wasp. With the aid of the previously constructed venom gland/sac-specific EST libraries, a total of 31 and 20 proteins were identified from 18 to 20 distinctive protein bands of E. pomiformis and O. drewseni venoms, respectively. Arginine kinase was the most predominant protein in both wasp venoms. Along with the full-length arginine kinase, a truncated form, which was known to have paralytic activity on a spider, was a common predominant protein in the two wasp venoms. Insulin/insulin-like peptide-binding protein was abundantly found only in E. pomiformis venom, which might be due to its unique behaviors of oviposition and provision. The presence of various immune response-related proteins and antioxidants suggested that wasps might use their venom to maintain prey fresh while feeding wasp larvae by protecting the prey from microbial invasion and physiological stresses. It seemed that some venom proteins are secreted into venom fluid from venom gland cells via exosomes, not by signal sequence-mediated transport processes.

Differential gene expression profiles in the venom gland/sac of Eumenes pomiformis (Hymenoptera: Eumenidae)

To search for novel transcripts encoding biologically active venom components, a subtractive cDNA library specific to the venom gland and sac (gland/sac) of a solitary hunting wasp species, Eumenes pomiformis Fabricius (1781), was constructed by suppression subtractive hybridization. A total of 541 expressed sequence tags (ESTs) were clustered and assembled into 102 contigs (31 multiple sequences and 71 singletons). In total, 37 cDNAs were found in the library via BLASTx searching and manual annotation. Eight contigs (337 ESTs) encoding short venom peptides (10 to 16 amino acids) occupied 62% of the library. The deduced amino acid sequence (78 amino acids) of a novel venom peptide transcript shared sequence similarity with trypsin inhibitors and dendrotoxin-like venom peptides known to be K(+) channel blockers, implying that this novel peptide may play a role in the paralysis of prey. In addition to phospholipase A2 and hyaluronidase, which are known to be the main components of wasp venoms, several transcripts encoding enzymes, including three metallopeptidases and a decarboxylase likely involved in the processing and activation of venomous proteins, peptides, amines, and neurotransmitters, were also isolated from the library. The presence of a transcript encoding a putative insulin/insulin-like peptide binding protein suggests that solitary hunting wasps use their venom to control their prey, leading to larval growth cessation. The abundance of these venom components in the venom gland/sac and in the alimentary canal was confirmed by quantitative real-time PCR. Discovery of venom gland/sac-specific transcripts should promote further studies on biologically active components in the venom of solitary hunting wasps.