Biochemical variability of venoms from individual European and Africanized honeybees (Apis mellifera)

Standardized guidelines for Africanized honeybee venom production needed for development of new apilic antivenom

Africanized bees have spread across the Americas since 1956 and consequently resulted in human and animal deaths attributed to massive attacks related to exposure from Argentina to the USA. In Brazil, more than 100,000 accidents were registered in the last 5 years with a total of 303 deaths. To treat such massive attacks, Brazilian researchers developed the first specific antivenom against Africanized honey bee sting exposure. This unique product, the first of its kind in the world, has been safely tested in 20 patients during a Phase 2 clinical trial. To develop the antivenom, a standardized process was undertaken to extract primary venom antigens from the Africanized bees for immunization of serum-producing horses. This process involved extracting, purifying, fractionating, characterizing, and identifying the venom (apitoxin) employing mass spectrometry to generate standardized antigen for hyperimmunization of horses using the major toxins (melittin and its isoforms and phospholipase A2). The current guide describes standardization of the entire production chain of venom antigens in compliance with good manufacturing practices (GMP) required by regulatory agencies. Emphasis is placed upon the welfare of bees and horses during this process, as well as the development of a new biopharmaceutical to ultimately save lives.

Experimental envenomation with honeybee venom melittin and phospholipase A2 induced multiple ultrastructural changes in adrenocortical mitochondria

Bee stings represent a public health subject, but the mechanisms involved in bee venom toxicity are not yet fully understood. To evaluate the reactions of adrenocortical cells, through which organisms respond to stress, two honeybee venom components: melittin (Mlt) and phospholipase A2 (PLA2) were tested as potential chemical stressors. Modifications were investigated with transmission electron microscopy and microanalysis. A single dose of Mlt (31 mg/kg) or PLA2 (9.3 mg/kg) was injected in rats of groups ML and PL; daily doses of Mlt (350 μg/kg) or PLA2 (105 μg/kg) were injected 30 days in rats of groups M30 and P30. Adrenocortical cells in ML group showed ultrastructural degenerative alterations of nuclei, endoplasmic reticulum, and mitochondria that exhibited lipid inclusions and mitochondrial cristae (MC) re-organized into mono- or multimembrane large vesicles, and whorls of membranes. Many MC were degenerated. In the M30 group, similar ultrastructural changes, but of lower amplitude were noted; lipid cytosolic droplets were heterogenous. MC diameters in Mlt groups (melittin treated groups) were significantly higher than in control (C) group. In PL group, mitochondria contained large lipid inclusions, vesicular MC of different sizes and multiple membranes, and debris, or whorl structures. In P30 group MC were tubular with increased diameters. In both PLA2 groups (PLA2 treated groups) MC were significantly larger than in C group. We concluded that Mlt and PLA2 were powerful stressors, toxic at the tested doses, cellular reactions concerning in all groups mainly mitochondria, but also other cellular compartments. Apart from degenerative regression of MC, the rearrangement of tubular MC occurred into one or multiple large multimembrane vesicular MC. Reactions to the high doses were more pronounced, with the highest amplitude in ML group, and the lowest in P30 group.

Wings and stings: Hymenoptera on vacation

Traveling to different regions, one might encounter a species to which they have a known allergy, or other related and unrelated species. A first-time systemic reaction can occur while on vacation, even in those with previous asymptomatic stings. Three main groups of Hymenoptera are responsible for most sting reactions. Honey bee species are virtually identical around the world. Among social wasps (family Vespidae), the yellowjacket (genus Vespula and Dolichovespula) and hornet (genus Vespa) venoms have almost complete cross-reactivity, whereas paper wasp (genus Polistes) venoms show only partial cross-reactivity with other vespid venoms. Venom immunotherapy (VIT) confers 80% to 95% protection against related insects, though isolated species of paper wasps and yellowjackets exist in every country that may be distinct from the ones at home. Those allergic to imported fire ants (genus Solenopsis) in the United States should not react to other ant species around the world. Stinging ants belong to several unrelated subfamilies in different geographic regions, which do not have cross-reactive venom. The chances of encountering specific species of Hymenoptera at a traveler's destination vary by location, planned activities, and season. In this article, we discuss special considerations for traveling, including distribution of stinging insects around the world, risk factors for more severe reactions, ways to prepare for a trip, and when allergist examination or treatment may be helpful before travel.

An evaluation of the chemical content and microbiological contamination of Anatolian bee venom

Bee venom is a natural substance produced by worker bees. The aim of this research paper is to determine the characteristics of Anatolian bee venom by evaluating its chemical content and microbiological properties. Physical, chemical and microbiological analyses were performed on 25 bee venom samples from different areas of Anatolia, Turkey. Data obtained by 3-replicate studies were evaluated with normality and one-way and two-way ANOVA / Tukey tests. Chemical analyses of the bee venoms revealed average melittin, apamin, and phospholipase A2 contents of 40.57%, 2.12% and 13.67%, respectively. The results suggest that Anatolian bee venom has a high phospholipase A2 content compared to the previous literature. The results for apamin content were similar to those reported in other countries. Melittin content was within the range of standard values. Bee venom samples were also observed to have a high sugar content, associated with pollen and nectar contamination. Total aerobic mesophilic bacteria counts revealed no microbial development in 11 samples of bee venom. Staphylococcus aureus was not detected in any sample. A low microbial load was associated with a high phospholipase A2 content in the bee venom composition, thus contributing to its antimicrobial character. This study presents an examination of Anatolian bee venom in terms of chemical content and microbial quality. The examination of other components in addition to phospholipase A2, melittin and apamin in future studies, together with an analysis of antimicrobial properties will further our understanding of Anatolian bee venom.

PGD2 /CRTH2 signaling promotes acquired immunity against bee venom by enhancing IgE production

IgE-dependent/independent activation of mast cell (MC) has been assumed to play a host defensive role against venom injection in skin. However, its detailed mechanisms remain unknown. We aimed to investigate the contribution of MC-derived prostaglandin D₂ (PGD₂ )-mediated signaling in host defense against bee venom (BV). To achieve this, we utilized gene-deficient mice of a PGD₂ receptor, chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2). We first confirmed that subcutaneous injection of BV produced PGD₂ equally in wild-type (WT) and CRTH2-deficient (Crth2^-/- ) mice skins. The BV injection dropped body temperature and impaired kidney equally in both lines of mice. In WT mice, pre-injection of BV (3 weeks) significantly inhibited the hypothermia and kidney impairment caused by second BV injection. In contrast, this pre-injection was not effective for the second BV injection in Crth2^-/- mice. We also found that BV injections increased serum BV-specific IgE levels in WT mice, and its serum transfused mice improved the BV-induced hypothermia in naïve WT mice. In contrast, serum BV-specific IgE level was significantly lower in Crth2^-/- mice. FACS analysis showed the BV injection stimulate migration of dendritic cells (DCs) into regional lymph nodes in WT mice. In Crth2^-/- mice, its number was significantly smaller than that of WT mice. In conclusion, PGD₂ /CRTH2 signaling plays defensive role against second BV injection. This signaling promotes BV-specific IgE production at least partially by promoting DCs migration into regional lymph node.

Insect Migration and Changes in Venom Allergy due to Climate Change

Insects are highly successful animals. They have limited ability to regulate their temperature and therefore will expand range in response to warming temperatures. Climate change and associated rising global temperature is impacting the range and distribution of stinging insects. There is evidence that many species are expanding range toward the poles, primarily in response to warming. With expanded distribution of stinging insects, increased interaction with humans is anticipated with consequently increased rates of sting-related reactions and need for intervention. This article focuses on evidence that insects are expanding their range in response to warming temperature, increasing likelihood of human interaction.

Toxicological study of bee venom (Apis mellifera mellifera) from different regions of the province of Buenos Aires, Argentina

Samples of Apis mellifera mellifera venom from different hives in two regions of the Buenos Aires province and its pool were analyzed for their lethal potency, myotoxic, defibrinogenating, hemolytic and inflammatory-edematizing activity and for the histological alterations they produce in the heart, lungs, kidneys, skeletal muscle and liver of mice. In vitro studies focused on the venom's hemolytic activity in different systems and species (horse, man, sheep and rabbit), the cytotoxicity in cellular lines, and on the proteolytic and coagulant activity in plasma and fibrinogen. Hemolytic activity, either observed in vitro or in vivo, showed similar toxicity levels for all samples. Erythrocytes of different species varied in their sensitivity to the venom pool, equines being the most sensitive and sheep the most resistant to direct hemolytic action. Local and systemic myotoxicity was evidenced by either the elevation of serum creatine kinase and/or histopathological lesions, observed in different muscles. All samples caused significant pathological alterations; pulmonary, cardiac, renal and skeletal muscle lesions were substantive and can be related to the pathophysiological mechanisms of envenomation. The venoms from different apiaries and regions of the Buenos Aires province showed very similar toxicological characteristics. These results suggest that severity of envenomation in case of a swarming could therefore be more related to the number of bees than to the differential toxicity of the venom from different regions of the province. This is the first study on the toxicity and toxicological characteristics of Apis mellifera venom in Argentina.

Hymenoptera allergy and anaphylaxis: are warmer temperatures changing the impact?

PURPOSE OF REVIEW

Climate change has brought about many changes in our ecosystem. Prolongation of pollen seasons has been reported, related to earlier frost off in the spring and later onset of frost on in the fall. This review considers recent global evidence that stinging insects are redistributing toward the poles, thereby potentially increasing human exposure and risk of sting events.

RECENT FINDINGS

With changing climate, particularly climate warming, range expansion of insects is occurring in both the Northern and Southern Hemispheres. Likewise, stinging insects, such as Hymenoptera and Lepidoptera, are also expanding range. Though there is scant data on associated increase of insect-related anaphylaxis, increased insect-human interaction is certain.

SUMMARY

It is likely that climate change will continue to alter the distribution and population of Hymenoptera and other insects. As temperatures warm and regions become suitable for nesting and establishment of colonies, many insects will expand their territory. As already reported in Alaska, one would anticipate expansion of range, especially toward the poles, thereby increasing the probability of human encounters and likewise anaphylaxis.

Honeybee Stings in the Era of Killer Bees: Anaphylaxis and Toxic Envenomation

BACKGROUND

Twenty-six years after the arrival of "killer bees" in Arizona, the entire state with the exception of high elevations in the north is populated with this bee variety and 11 people have died at the scene of massive bee attacks.

METHODS

Because of the aggressive behavior of these bees we studied bee stings reported to the Arizona Poison and Drug Information Center. The center received 399 calls regarding 312 victims of bee stings from January 2017 to June 2019. Calls originated from private residences and emergency centers.

RESULTS

Stings occurred at victims' home residences in 272 (84.7%) of cases and 24 (7.5%) in public areas; 251 people suffered 1 sting; 42 individuals, 2-10 stings, 4 had 11-49 stings, and 13 individuals had >50 stings (so-called massive stinging). Three individuals were admitted to intensive care units (ICU) and one 35-year-old man died of anaphylaxis after 1 sting; moderate clinical effects occurred in 32 individuals including 6 admitted to the hospital but not in the intensive care unit. Anaphylaxis occurred in 30 (9.6%) of individuals, 16 receiving 1 sting. Toxic effects, tachycardia, elevated creatinine, or rhabdomyolysis occurred in 13 (4.2%) individuals.

CONCLUSIONS

In the past, individuals stung more than 50 times were beekeepers working with European honeybees, whereas, in the current era, single as well as massive stings are the result of feral "killer bees." This change in epidemiology requires a new approach to sting victims: those with massive stinging should be evaluated and observed for anaphylaxis and serial laboratory values obtained for days to detect the toxic effects of envenomation.

Worldwide perspectives on venom allergy

Venom immunotherapy is the standard of care for people with severe reactions and has been proven to reduce risk of future anaphylactic events. There is a moral imperative to ensure production, supply and worldwide availability of locally relevant, registered, standardized commercial venom extracts for diagnosis and treatment. Insects causing severe immediate allergic reactions vary by region worldwide. The most common culprits include honeybees (Apis mellifera), social wasps including yellow jackets (Vespula and Dolichovespula), paper wasps (Polistes) and hornets (Vespa), stinging ants (Solenopsis, Myrmecia, Pachycondyla, and Pogonomyrmex), and bumblebees (Bombus). Insects with importance in specific areas of the world include the Australian tick (Ixodes holocyclus), the kissing bug (Triatoma spp), horseflies (Tabanus spp), and mosquitoes (Aedes, Culex, Anopheles). Reliable access to high quality venom immunotherapy to locally relevant allergens is not available throughout the world. Many current commercially available therapeutic vaccines have deficiencies, are not suitable for, or are unavailable in vast areas of the globe. New products are required to replace products that are unstandardized or inadequate, particularly whole-body extract products. New products are required for insects in which no current treatment options exist. Venom immunotherapy should be promoted throughout the world and the provision thereof be supported by health authorities, regulatory authorities and all sectors of the health care service.

Bee Updated: Current Knowledge on Bee Venom and Bee Envenoming Therapy

Honey bees can be found all around the world and fulfill key pollination roles within their natural ecosystems, as well as in agriculture. Most species are typically docile, and most interactions between humans and bees are unproblematic, despite their ability to inject a complex venom into their victims as a defensive mechanism. Nevertheless, incidences of bee stings have been on the rise since the accidental release of Africanized bees to Brazil in 1956 and their subsequent spread across the Americas. These bee hybrids are more aggressive and are prone to attack, presenting a significant healthcare burden to the countries they have colonized. To date, treatment of such stings typically focuses on controlling potential allergic reactions, as no specific antivenoms against bee venom currently exist. Researchers have investigated the possibility of developing bee antivenoms, but this has been complicated by the very low immunogenicity of the key bee toxins, which fail to induce a strong antibody response in the immunized animals. However, with current cutting-edge technologies, such as phage display, alongside the rise of monoclonal antibody therapeutics, the development of a recombinant bee antivenom is achievable, and promising results towards this goal have been reported in recent years. Here, current knowledge on the venom biology of Africanized bees and current treatment options against bee envenoming are reviewed. Additionally, recent developments within next-generation bee antivenoms are presented and discussed.

Ultrastructural variability of mitochondrial cristae induced in vitro by bee (Apis mellifera) venom and its derivatives, melittin and phospholipase A2, in isolated rat adrenocortical mitochondria

We tested the ability of bee venom (BV), melittin (Mlt), and phospholipase A2 (PLA) - used in 5 concentrations each (5, 10, 15, 20 and 40 μg/100 μl) - to promote ultrastructural changes and reorganization of cristae in vitro in mitochondria isolated from rat adrenal cortex after a protocol optimized by us. Thus, apart from two control grups (CI and CS), in which the mitochondria were suspended into saline buffer and isolation medium respectively, 15 more groups of mitochondria were constituted, corresponding to the five different doses of the three substance tested (BV5 to M40; M5 to M40 and P5 to P40). The ultrastructural effects were quantified on transmission electron micrographs using a morphometry software. Values of 84.49 nm and 95.45 nm were calculated for median diameters of mitochondrial cristae in two control groups. Large and very large vesicular cristae, many with 2 or 3 membranes, were generated depending on dose among normal cristae in all treated groups. In the BV and Mlt treated groups, after an initial increase (up to 127.27 nm in V15 group and 151.2 nm in M10 group) due to stimulation of cristae fusion, the cristae diameter diminished as the doses increased, mainly by the collapse of the cristae. In the PLA treated groups, the cristae diameter increased continuously from 83.84 nm to 136.01 nm, by stimulated fusion of cristae, only the two largest doses promoting the collapse of cristae in some mitochondria. The highest percentage of abnormal cristae was found in the Mlt treated groups and next in BV treated groups. All substances tested produced pronounced ultrastructural variability of mitochondrial cristae in vitro: they also changed (depending on dose) mitochondrial shapes, generated matrix debris and the highest concentrations of BV and Mlt were responsible for mitochondrial breakdown. These ultrastructural alterations of mitochondrial criste in the presence of the BV molecules suggest a reduced capacity of adrenocortical mitochondria to synthetize steroid hormones consequently to BV envenomations and partially explain the toxic effects of the BV.

Ultrastructural analysis of early toxic effects produced by bee venom phospholipase A2 and melittin in Sertoli cells in rats

In this study, we aimed to investigate the testicular toxicity of two molecules derived from bee venom (BV): phospholipase A2 (PlA2) and melittin (Mlt). Ultrastructural effects of purified BV PlA2 and Mlt were assessed consecutive to repeated dose (30 days) and acute toxicity studies. For the subchronic treatment, PlA2 and Mlt were injected in daily doses equivalent to those released by a bee sting (105 μg PlA2/kg/day and 350 μg Mlt/kg/day), while in the acute treatment their doses corresponded to those released by 100 bee stings (9.3 mg PlA2/kg and 31 mg Mlt/kg). Both PlA2 and Mlt affected the Leydig cells and the cells in seminiferous tubules, the Sertoli cells first of all. PlA2 injection resulted in detachment of the Sertoli cells from the surrounding cells, and extracellular vacuolations, cytoplasmic vacuolations in their basal region and in branches as well, detachment of spermatids, residual bodies and sometimes even spermatocytes into the lumen, changes that had a higher magnitude after the acute treatment. Mlt injection induced similar ultrastructural alterations, but more severe, including degeneration of cellular organelles and cellular necrosis, resulting into rarefaction of the seminiferous epithelium; the ultrastructural changes had a higher magnitude after the 30 repeated dose treatment. We concluded that either of the two molecules tested here, PlA2 and Mlt, were Sertoli cells toxicants at the used doses, and they participated both in the BV testicular toxicity. We consider the observed changes as part of a preceding mechanism of the more severe alterations produced by the BV. It also remains possible that these early unspecific changes reported here could represent the response of the SCs not only to the components of bee venom, but to molecules of other venoms as well. The Sertoli cells were the primary target of PlA2 and Mlt in the spermatogenic epithelium, and their alteration led to further degenerative changes of the germ cells. Since the exposure to PlA2 and Mlt caused severe alteration, including cell death and detachment of immature germ cells into the lumen, we may also conclude that the bee venom molecules had a potential to interfere with normal progression of spermatogenesis. All the degenerative changes observed in the Sertoli cells were accompanied with changes of the Leydig cells.

Histopathological and ultrastructural changes experimentally induced by bee venom in seminiferous epithelium via structural-functional alteration of Sertoli cells

We tested here the ability of bee venom (BV) to interfere with spermatogenesis in rats in two experimental conditions. The histopathological changes were assessed with brightfield microscopy using a novel staining technique, based on methylene blue, orange G and ponceau xylidine. Transmission electron microscopy was also used to identify fine subcellular changes. BV injection for 30days in daily doses of 700μg BV/kg resulted in reducing testicular weight, along with significant larger diameters of seminiferous tubules and reduced number of Sertoli cells (SCs). SCs were vacuolated, detached from the basement membrane, many necrosed, leading to the basement membrane denudation. Germ cells layers were separated by empty spaces conferring a rarefied aspect to the tissue, and spermatids were detached into lumen. Thus, the seminiferous epithelium was significantly thinned. Many Leydig cells (LCs) were in a necrotic state, with disrupted plasma membrane and without smooth endoplasmic reticulum. The acute treatment with a single LD50 of 62mgBV/kg, was followed by focal disruptions of the basement membrane and localized areas of necrosis, mainly affecting the SCs. Most of the observed SCs as well as some spermatogonia were highly vacuoled, empty spaces being observed within the epithelium. The SCs count was significantly decreased. Spermatids had also the tendency of separation from the SCs, and the significant larger diameter of the tubules found was associated with a thicker epithelium. Many LCs were necrosed, with disrupted plasma membrane, swollen mitochondria, no endoplasmic reticulum and implicitly showing rarefied cytoplasm. We concluded that BV was a testicular toxicant affecting both the LCs and the seminiferous tubules. The SCs cells represented the primary target site of BV whose effects were next extended upon the germ cells. In all cells, BV triggered unspecific degenerative changes that could impaire spermatogenesis. The present study also proposes an alternative staining technique very useful in assessing the histopathological aspects of spermatogenesis.

De novo sequencing and transcriptome analysis of venom glands of endoparasitoid Aenasius arizonensis (Girault) (=Aenasius bambawalei Hayat) (Hymenoptera, Encyrtidae)

Aenasius bambawalei Hayat (Encyrtidae: Hymenoptera) has been synonymized with Aenasius arizonensis (Girault) is a small, newly discovered endoparasitoid of the cotton mealybug Phenacoccuss solenopsis Tinsley (Pseudococcidae: Hemiptera), which completes its life cycle inside the body of its host and it is a potential insect control tool. Despite the acquired knowledge regarding host-parasitoid interaction, little information is available on the factors of parasitoid origin able to modulate mealybug physiology. The components of A. arizonensis venom have not been well studied but venom from other parasitoids and wasps contain biologically active proteins that have potential applications in pest management or may be of medicinal importance. To provide an insight into the transcripts expressed in the venom gland of A. arizonensis, a transcriptomic database was developed utilizing high throughput RNA sequencing approaches to analyze the genes expressed in venom glands of this endoparasitic wasp. The resulting A. arizonensis RNA sequences were assembled de-novo with contigs then blasted against the NCBI non-redundant sequence database. Contigs which matched database sequences were mostly homologous to genes from hymenopteran parasitoids such as Nasonia vitripennis, Copidosoma floridanum, Fopius arsenus and Pteromalas puparium. Further analysis of the A. arizonensis database was then performed which focused on selected genes encoding proteins potentially involved in host developmental arrest, disrupting the host immune system, host paralysis, and transcripts that support these functions. Sequenced mRNAS predicted to encode full length ORFs of Calreticulin, Serine Protease Precursor and Arginine kinase proteins were identified and the tissue specific expression of these putative venom genes was analyzed by RT-PCR. In addition, results also demonstrate that de novo transcriptome assembly allows useful venom gene expression analysis in a species lacking a genome sequence database and may provide useful information for devising control tools for insect pests and other applications.

Melittin, the Major Pain-Producing Substance of Bee Venom

Melittin is a basic 26-amino-acid polypeptide that constitutes 40-60% of dry honeybee (Apis mellifera) venom. Although much is known about its strong surface activity on lipid membranes, less is known about its pain-producing effects in the nervous system. In this review, we provide lines of accumulating evidence to support the hypothesis that melittin is the major pain-producing substance of bee venom. At the psychophysical and behavioral levels, subcutaneous injection of melittin causes tonic pain sensation and pain-related behaviors in both humans and animals. At the cellular level, melittin activates primary nociceptor cells through direct and indirect effects. On one hand, melittin can selectively open thermal nociceptor transient receptor potential vanilloid receptor channels via phospholipase A2-lipoxygenase/cyclooxygenase metabolites, leading to depolarization of primary nociceptor cells. On the other hand, algogens and inflammatory/pro-inflammatory mediators released from the tissue matrix by melittin's pore-forming effects can activate primary nociceptor cells through both ligand-gated receptor channels and the G-protein-coupled receptor-mediated opening of transient receptor potential canonical channels. Moreover, subcutaneous melittin up-regulates Nav1.8 and Nav1.9 subunits, resulting in the enhancement of tetrodotoxin-resistant Na(+) currents and the generation of long-term action potential firing. These nociceptive responses in the periphery finally activate and sensitize the spinal dorsal horn pain-signaling neurons, resulting in spontaneous nociceptive paw flinches and pain hypersensitivity to thermal and mechanical stimuli. Taken together, it is concluded that melittin is the major pain-producing substance of bee venom, by which peripheral persistent pain and hyperalgesia (or allodynia), primary nociceptive neuronal sensitization, and CNS synaptic plasticity (or metaplasticity) can be readily induced and the molecular and cellular mechanisms underlying naturally-occurring venomous biotoxins can be experimentally unraveled.

High-performance liquid chromatography combined with intrinsic fluorescence detection to analyse melittin in individual honeybee (Apis mellifera) venom sac

Melittin is the major toxin peptide in bee venom, which has diverse biological effects. In the present study, melittin was separated by reverse-phase high-performance liquid chromatography, and was then detected using intrinsic fluorescence signal of tryptophan residue. The accuracy, linearity, limit of quantitation (LOQ), intra-day and inter-day precision of the method were carefully validated in this study. Results indicate that the intrinsic fluorescence signal of melittin has linear range from 0.04μg/mL to 20μg/mL with LOQ of 0.04μg/mL. The recovery range of spiked samples is between 81.93% and 105.25%. The precision results are expressed as relative standard deviation (RSD), which is in the range of 2.1-7.4% for intra-day precision and 6.2-10.8% for inter-day precision. Because of the large linear dynamic range and the high sensitivity, intrinsic fluorescence detection (IFD) can be used for analyzing melittin contents in individual venom sac of honeybee (Apis mellifera). The detected contents of melittin in individual bee venom sac are 0.18±0.25μg for one-day old honeybees (n=30), and 114.98±43.51μg for 25-day old (n=30) honeybees, respectively. Results indicate that there is large bee-to-bee difference in melittin contents. The developed method can be useful for discovering the melittin related honeybee biology information, which might be covered in the complex samples.

De Novo sequencing and transcriptome analysis for Tetramorium bicarinatum: a comprehensive venom gland transcriptome analysis from an ant species

BACKGROUND

Arthropod venoms are invaluable sources of bioactive substances with biotechnological application. The limited availability of some venoms, such as those from ants, has restricted the knowledge about the composition and the potential that these biomolecules could represent. In order to provide a global insight on the transcripts expressed in the venom gland of the Brazilian ant species Tetramorium bicarinatum and to unveil the potential of its products, high-throughput approach using Illumina technology has been applied to analyze the genes expressed in active venom glands of this ant species.

RESULTS

A total of 212,371,758 pairs of quality-filtered, 100-base-pair Illumina reads were obtained. The de novo assemblies yielded 36,042 contigs for which 27,873 have at least one predicted ORF among which 59.77% produce significant hits in the available databases. The investigation of the reads mapping toxin class revealed a high diversification with the major part consistent with the classical hymenopteran venom protein signature represented by venom allergen (33.3%), followed by a diverse toxin-expression profile including several distinct isoforms of phospholipase A1 and A2, venom serine protease, hyaluronidase, protease inhibitor and secapin. Moreover, our results revealed for the first time the presence of toxin-like peptides that have been previously identified from unrelated venomous animals such as waprin-like (snakes) and agatoxins (spiders and conus).The non-toxin transcripts were mainly represented by contigs involved in protein folding and translation, consistent with the protein-secretory function of the venom gland tissue. Finally, about 40% of the generated contigs have no hits in the databases with 25% of the predicted peptides bearing signal peptide emphasizing the potential of the investigation of these sequences as source of new molecules. Among these contigs, six putative novel peptides that show homologies with previously identified antimicrobial peptides were identified.

CONCLUSIONS

To the best of our knowledge, this work reports the first large-scale analysis of genes transcribed by the venomous gland of the ant species T. bicarinatum and helps with the identification of Hymenoptera toxin arsenal. In addition, results from this study demonstrate that de novo transcriptome assembly allows useful venom gene expression analysis in a species lacking a genome sequence database.

Neutralization of Apis mellifera bee venom activities by suramin

In this work we evaluated the ability of suramin, a polysulfonated naphthylurea derivative, to antagonize the cytotoxic and enzymatic effects of the crude venom of Apis mellifera. Suramin was efficient to decrease the lethality in a dose-dependent way. The hemoconcentration caused by lethal dose injection of bee venom was abolished by suramin (30 μg/g). The edematogenic activity of the venom (0.3 μg/g) was antagonized by suramin (10 μg/g) in all treatment protocols. The changes in the vascular permeability caused by A. mellifera (1 μg/g) venom were inhibited by suramin (30 μg/g) in the pre- and posttreatment as well as when the venom was preincubated with suramin. In addition, suramin also inhibited cultured endothelial cell lesion, as well as in vitro myotoxicity, evaluated in mouse extensor digitorum longus muscle, which was inhibited by suramin (10 and 25 μM), decreasing the rate of CK release, showing that suramin protected the sarcolemma against damage induced by components of bee venom (2.5 μg/mL). Moreover, suramin inhibited the in vivo myotoxicity induced by i.m. injection of A. mellifera venom in mice (0.5 μg/g). The analysis of the area under the plasma CK vs. time curve showed that preincubation, pre- and posttreatment with suramin (30 μg/g) inhibited bee venom myotoxic activity in mice by about 89%, 45% and 40%, respectively. Suramin markedly inhibited the PLA2 activity in a concentration-dependent way (1-30 μM). Being suramin a polyanion molecule, the effects observed may be due to the interaction of its charges with the polycation components present in A. mellifera bee venom.

Bee Venom Attenuates Experimental Autoimmune Encephalomyelitis through Direct Effets on CD4+CD25+FOXP3+ T Cells

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system that leads to substantial disability through deficits of sensation and of motor, autonomic, and neuro-cognitive function. Many clinical and pathological features of experimental autoimmune encephalomyelitis (EAE) show close similarity to MS. Bee venom (BV) has been used in the practice of oriental medicine and evidence from the literature indicates that BV plays an anti-inflammatory or anti-nociceptive role against inflammatory reactions associated with arthritis and other inflammatory diseases. The purpose of the present study was to determine whether BV could suppress immune cell differentiation and infiltration into spinal cord on EAE mice commonly used as a model for MS. BV treatment increased the population of CD4+CD25+Foxp3+ T cells and inhibited CD4+ T-cell proliferation in vitro. In vivo, BV treatment increased the population of CD4+CD25+Foxp3+ T cells. Furthermore, BV administration reduced the severity of EAE while concurrently decreasing INF-γ producing CD4+T cells, IL-17A producing CD4+T cells and inflammatory cytokine production including INF-γ, IL-17A, TNF and IL-6. BV-treated animals exhibited less infiltration and preserved morphology compared to saline-treated animals. Interestingly, the therapeutic effects of BV on EAE disappeared when CD4+CD25+Foxp3+ T cells were depleted by using anti-CD25 antibody. Our research suggests that BV could be a potential therapeutic agent for antiinflammatory effects in an animal model of EAE.

Africanized honeybee stings: how to treat them

INTRODUCTION

In 1956, Africanized honeybees (AHB) migrated from Brazil to other regions of the Western Hemisphere, including South, Central, and North America, except for Canada. Despite being productive, they are highly aggressive and cause fatal accidents. This study aimed to evaluate patients at the Clinical Hospital of Botucatu Medical School (HC-FMB) and to propose treatment guidelines.

METHODS

From 2005 to 2006, the clinical and laboratorial aspects of 11 patients (7 male and 4 female) and the anatomopathological aspects of one patient who had died in 2003 were analyzed.

RESULTS

The age of the surviving patients varied from 5 to 87 years, with a mean of 42.5 years. The majority of accidents occurred in the afternoon, and the number of stings ranged from 20 to 500. The principal signs and symptoms were pain and local inflammatory signs, nausea, tachycardia, and vomiting. Biochemical findings presented increased levels of creatine phosphokinase, lactate dehydrogenase, and aspartate/alanine aminotransferase. An 11-year-old male patient died upon entering the attic of a two-story building where he was attacked by a swarm, receiving more than 1,000 stings. He was sent to HC-FMB where he was treated, but he died 24h later. Observed at the autopsy were erythematous-purpuric skin lesions besides necrosis at the sting locations, rhabdomyolysis, focal myocardial necrosis, tubular hydropic degeneration and focal tubular acute necrosis of the kidneys, myoglobinuria, and centrolobular necrosis in the liver.

CONCLUSIONS

Accidents caused by multiple AHB stings always constitute a medical emergency. As there is no specific antivenom, we have developed guidelines, including first aid, drugs, and the proper removal of stingers.

Historical perspective and human consequences of Africanized bee stings in the Americas

In 1956, Africanized bees began to spread in the American continent from southern Brazil, where original African bees mated with European bees. A few years later, in 1990, these Africanized bees reached the United States and were found in Texas. Currently, these hybrid bees are found in several North American states and will probably reach the Canadian border in the future. Although the presence of Africanized bees had produced positive effects on Brazilian economy, including improvement in crop pollination and in honey production, turning Brazil into a major exporter, the negative impacts-such as swarming, aggressive behavior, and the ability to mass attack-resulted in serious and fatal envenomation with humans and animals. Victims of bee attacks usually develop a severe envenomation syndrome characterized by the release of a large amount of cytokines [interleukins (IL) IL-1, IL-6, IL-8], and tumor necrosis factor (TNF). Subsequently, such cytokines produce an acute inflammatory response that triggers adverse effects on skeletal muscles; bone marrow; hepatic and renal functions; and cardiovascular, central nervous, and immune systems. Finally, the aim of the present review is to study historical characteristics and current status of Africanized bees' spread, the composition of their venom, the impact of the bees on the Brazilian economy and ecology, and clinical aspects of their stings including immune response, and to suggest a protocol for bee sting management since there is no safe and effective antivenom available.

The sting of the honeybee: an allergic perspective

OBJECTIVE

To provide a focused understanding of the uniqueness and special considerations of honeybee allergy.

DATA SOURCES

A PubMed search using the keywords honeybee, allergy, and hypersensitivity yielded the initial relevant articles. Additional significant sources cited in the reference lists of the initial articles were also used.

STUDY SELECTION

More than 130 articles were reviewed, and the most relevant references were selected for inclusion in this article.

RESULTS

The honeybee differs from other flying Hymenoptera from both an entomologic and allergic standpoint. The entomology literature is not often consulted by the allergist when addressing avoidance of honeybees. Beekeepers are a particular population at risk for honeybee exposure and allergy. Venom composition, sting mechanism, diagnostic evaluation, and immunotherapy efficacy and safety all have unique considerations specific to the honeybee.

CONCLUSIONS

Honeybee is a significant cause of venom hypersensitivity. By understanding unique behaviors of honeybees, proper avoidance measures may be addressed with patients. Honeybee venom is complex, and the delivery mechanism provides for a large but often variable amount of injected venom. Diagnosis of honeybee allergy by imperfect skin and serologic testing further complicated by cross-reactivity is often difficult. Generally, honeybee immunotherapy is less safe and less effective than for other flying Hymenoptera. Efforts to improve testing and immunotherapy are under way.

New CZE-DAD method for honeybee venom analysis and standardization of the product

The aim of this study was to develop a new precise and accurate CZE-DAD method for honeybee venom analysis using cytochrome c as an internal standard. The 64.5 cm total length, 56 cm effective length, 75 μm ID, and 360 μm OD uncoated fused-silica capillary was used. The samples were injected into the capillary under a 50-mbar pressure for 7 s. There were 15 kV of electric field across the capillary applied. The current intensity was 26 μA. The separation was carried out at 25 °C. The analysis was run with the normal electrode polarity. The following steps and parameters were taken into account for the validation of the developed method: selectivity, precision, accuracy, linearity, limit of detection and limit of quantitation. All steps of the validation procedure proved that the developed analytical procedure was suitable for its intended purpose. Possibly this was the first study in which several honeybee venom components were separated and five of them were identified by capillary zone electrophoresis. In addition, the developed method was applied for quantitative analysis of 38 honeybee venom samples. The content (relative to the dry venom mass) of analyzed peptides in honeybee venom samples collected in 2002–2007 was as follows: apamine from 0.93% to 4.34% (mean, 2.85 ± 0.79%); mast cell degranulating peptide (MCDP) from 1.46% to 4.37% (mean, 2.82 ± 0.64%); phospholipase A₂ from 7.41% to 20.25% (mean, 12.95 ± 3.09%); melittin from 25.40% to 60.27%, (mean, 45.91 ± 9.78%). The results were compared with the experimental data obtained for the same venom samples analyzed earlier by the HPLC method. It was stated that HPCE and HPLC data did not differ significantly and that the HPCE method was the alternative for the HPLC method. Moreover, using the results obtained principal component analysis (PCA) was applied to clarify the general distribution patterns or similarities of four major honeybee venom constituents collected from two different bee strains in various months and years. PCA has shown that the strain of bee appears to be the only criteria for bee venom sample classification. Strong correlations between apamine, MCDP, phospholipase A₂, and melittin were confirmed. These correlations have to be taken into account in the honeybee venom standardization. The developed method due to its simplicity can be easily automated and incorporated into routine operations both in the bee venom identification, quality control, and standardization of the product.

The nociceptive and anti-nociceptive effects of bee venom injection and therapy: a double-edged sword

Bee venom injection as a therapy, like many other complementary and alternative medicine approaches, has been used for thousands of years to attempt to alleviate a range of diseases including arthritis. More recently, additional theraupeutic goals have been added to the list of diseases making this a critical time to evaluate the evidence for the beneficial and adverse effects of bee venom injection. Although reports of pain reduction (analgesic and antinociceptive) and anti-inflammatory effects of bee venom injection are accumulating in the literature, it is common knowledge that bee venom stings are painful and produce inflammation. In addition, a significant number of studies have been performed in the past decade highlighting that injection of bee venom and components of bee venom produce significant signs of pain or nociception, inflammation and many effects at multiple levels of immediate, acute and prolonged pain processes. This report reviews the extensive new data regarding the deleterious effects of bee venom injection in people and animals, our current understanding of the responsible underlying mechanisms and critical venom components, and provides a critical evaluation of reports of the beneficial effects of bee venom injection in people and animals and the proposed underlying mechanisms. Although further studies are required to make firm conclusions, therapeutic bee venom injection may be beneficial for some patients, but may also be harmful. This report highlights key patterns of results, critical shortcomings, and essential areas requiring further study.

Africanized honey bee (Apis mellifera) venom profiling: Seasonal variation of melittin and phospholipase A(2) levels

Apis mellifera venom is comprised basically of melittin, phospholipase A(2), histamine, hyaluronidase, catecholamine and serotonin. Some of these components have been associated with allergic reactions, amongst several other symptoms. On the other hand, bee mass stinging, caused by Africanized honey bee (AHB), is increasingly becoming a serious public health issue in Brazil; therefore, the development of efficient serum-therapies has become necessary. In this work, we have analyzed the venom composition of AHB in Brazil through one year. In order to verify the homogeneity of this venom, one specific hive was selected and the correlation with climatic parameters was assessed. It was possible to perceive a seasonal variation on the venom contents of melittin and phospholipase A(2). Moreover, both compounds presented a synchronized variation of their levels, with an increased production in the same months. This variation does not correlate or synchronize with any climatic parameter. Data on the variation of the AHB venom composition is necessary to guide future intra and inter species studies.

Mechanisms of bee venom-induced acute renal failure

The spread of Africanized bees in the American continent has increased the number of severe envenomation after swarm attacks. Acute renal failure (ARF) is one of the major hazards in surviving patients. To assess the mechanisms of bee venom-induced ARF, rats were evaluated before, up to 70 min and 24h after 0.5mg/kg of venom injection. Control rats received saline. Bee venom caused an early and significant reduction in glomerular filtration rate (GFR, inulin clearance, 0.84+/-0.05 to 0.40+/-0.08 ml/min/100g, p<0.0001) and renal blood flow (RBF, laser Doppler flowmetry), which was more severe in the cortical (-72%) than in the medullary area (-48%), without systemic blood pressure decrease. Creatine phosphokinase, lactic dehydrogenase (LDH) and serum glutamic oxaloacetic transaminase increased significantly, pointing to rhabdomyolysis, whereas serum glutamic pyruvic transaminase and hematocrit remained stable. Twenty-four hours after venom, RBF recovered but GFR remained significantly impaired. Renal histology showed acute tubular injury and a massive tubular deposition of myoglobin. Venom was added to isolated rat proximal tubules (PT) suspension subjected to normoxia and hypoxia/reoxygenation (H/R) for direct nephrotoxicity evaluation. After 60 min of incubation, 0.1, 2 and 10 microg of venom induced significant increases in LDH release: 47%, 64% and 86%, respectively, vs. 21% in control PT while 2 microg of venom enhanced H/R injury (85% vs. 55%, p<0.01). These results indicate that vasoconstriction, direct nephrotoxicity and rhabdomyolysis are important mechanisms in the installation of bee venom-induced ARF that may occur even without hemolysis or hypotension.

Diagnosis of Hymenoptera venom allergy

The purpose of diagnostic procedure is to classify a sting reaction by history, identify the underlying pathogenetic mechanism, and identify the offending insect. Diagnosis of Hymenoptera venom allergy thus forms the basis for the treatment. In the central and northern Europe vespid (mainly Vespula spp.) and honeybee stings are the most prevalent, whereas in the Mediterranean area stings from Polistes and Vespula are more frequent than honeybee stings; bumblebee stings are rare throughout Europe and more of an occupational hazard. Several major allergens, usually glycoproteins with a molecular weight of 10-50 kDa, have been identified in venoms of bees, vespids. and ants. The sequences and structures of the majority of venom allergens have been determined and several have been expressed in recombinant form. A particular problem in the field of cross-reactivity are specific immunoglobulin E (IgE) antibodies directed against carbohydrate epitopes, which may induce multiple positive test results (skin test, in vitro tests) of still unknown clinical significance. Venom hypersensitivity may be mediated by immunologic mechanisms (IgE-mediated or non-IgE-mediated venom allergy) but also by nonimmunologic mechanisms. Reactions to Hymenoptera stings are classified into normal local reactions, large local reactions, systemic toxic reactions, systemic anaphylactic reactions, and unusual reactions. For most venom-allergic patients an anaphylactic reaction after a sting is very traumatic event, resulting in an altered health-related quality of life. Risk factors influencing the outcome of an anaphylactic reaction include the time interval between stings, the number of stings, the severity of the preceding reaction, age, cardiovascular diseases and drug intake, insect type, elevated serum tryptase, and mastocytosis. Diagnostic tests should be carried out in all patients with a history of a systemic sting reaction to detect sensitization. They are not recommended in subjects with a history of large local reaction or no history of a systemic reaction. Testing comprises skin tests with Hymenoptera venoms and analysis of the serum for Hymenoptera venom-specific IgE. Stepwise skin testing with incremental venom concentrations is recommended. If diagnostic tests are negative they should be repeated several weeks later. Serum tryptase should be analyzed in patients with a history of a severe sting reaction.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and high-performance liquid chromatography study of quantitative and qualitative variation in tarantula spider venoms

Animal venoms are important sources of novel pharmacological tools, useful in biochemical characterization of their receptors. Venom quality control, batch-to-batch homogeneity and high reproducibility of venom fractionation and toxin purification are crucial issues for biochemical and pharmacological studies. To address these issues, a study of the variability of tarantula spider venom samples was undertaken. Venom profiles of samples collected from individuals of different age and sex, and from sibling spiders of the same species, were generated by high-performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) and analyzed to assess venom variability and method accuracy. Sex-linked venom variation was studied on eight species. Clear qualitative differences were observed for six out of eight species, as well as quantitative differences. Age-related variation studied in Poecilotheria rufilata showed essentially age-related quantitative differences between adults of both sexes and immature juveniles. The venoms of nine siblings and three wild-collected Pterinochilus murinus were studied for individual variation, showing only very minor quantitative differences. On the same samples, the quality of MALDI-TOFMS venom fingerprinting was demonstrated to be highly reproducible. Our results show that tarantula venom peptide fingerprinting is a highly reliable identification method, that pooled batches of venom from several animals can be used for venom purification, that venom composition does not appear to be qualitatively related to ontogenesis in the spiders studied, and that qualitative sex-linked variation occurs across most species and may be important in activity studies.

Api m 6: a new bee venom allergen

BACKGROUND

Characterization of the primary structure of allergens is a prerequisite for the design of new diagnostic and therapeutic tools for allergic diseases.

OBJECTIVE

The purpose of this study was the identification and characterization of a low-molecular-weight, IgE-binding, bee venom (BV) allergen.

METHODS

BV proteins were separated by using size exclusion chromatography and HPLC. IgE antibody binding to purified proteins was analyzed by means of immunoblotting, and T-cell response was analyzed by means of proliferation assay. Amino acid sequence was determined with 2 approaches, namely Edman degradation and carboxy terminal analysis with mass spectrometry.

RESULTS

Api m 6, which migrated as an 8-kd band in SDS-PAGE, was frequently (42%) recognized by IgE from BV-hypersensitive patients. In addition, PBMCs from BV-hypersensitive patients, as well as from a normal control subject, proliferated in response to this allergen. Api m 6 exists as 4 isoforms of 7190, 7400, 7598, and 7808 d, respectively. Amino acid sequences obtained from HPLC-purified preparations revealed that the isoforms were constituted of a common central core of 67 residues, only differing in the amino- and carboxy-terminal ends. Api m 6 showed no significant sequence homology with known proteins.

CONCLUSIONS

We have identified and sequenced a new BV allergen that elicits a strong IgE and T-cell response in a large number of BV-hypersensitive patients. Api m 6 should be considered in the diagnostic and therapeutic approach of BV immunotherapy on the basis of peptides or recombinant proteins.

Mechanism of action of honey bee (Apis mellifera L.) venom on different types of muscles

1. The effect of crude honeybee (Apis mellifera) venom on the skeletal, smooth as well as cardiac muscles were studied in this investigation. 2. Perfusion of gastrocnemius-sciatic nerve preparation of frogs with 1 microgram/ml venom solution has weakened the mechanical contraction of the muscle without recovery. Blocking of nicotinic receptors with 3 micrograms/ml flaxedil before bee venom application sustained normal contraction of gastrocnemius muscle. 3. The electrical activity of duodenum rabbits was recorded before and after the application of 1 microgram/ml venom solution. The venom has depressed the amplitude of the muscle contraction after 15 min pretreatment with atropine nearly abolished the depressor effect of the venom on smooth muscle. 4. In concentrations from 0.5-2 micrograms/ml, bee venom caused decrease of heart rate of isolated perfused toad heart. This bradycardia was accompanied by elongation in the P-R interval. A gradual and progressive increase in the R-wave amplitude reflected a positive inotropism of the venom. Application of 5 micrograms/ml verapamil, a calcium channels blocking agent, abolished the noticed effect of the venom. 5. Marked electrocardiographic changes were produced within minutes of the venom application on the isolated perfused hearts, like marked injury current (elevation or depression of the S-T segment), atrioventricular conduction disturbances and sinus arrhythmias. Atropine and nicotine could decrease the toxic effect of the venom on the myocardium. 6. Results of the present work lead to the suggestion that bee venom is mediated through the peripheral cholinergic neurotransmitter system. General neurotoxicity of an inhibitory nature involving the autonomic as well as neuromuscular system are established as a result of the venom, meanwhile a direct effect on the myocardium membrane stabilization has been suggested.

Toxinology of venoms from the honeybee genus Apis

The venoms of Apis dorsata, A. cerana, A. florea, and three different populations of A. mellifera were compared for lethal activity toward mice. All venoms exhibited identical activities, a finding consistent with recent evolutionary history within the genus. Young queen honeybees use their venoms only for stinging other queens and possess a venom only half as lethal to mice as worker venom, and by the time queens are 1-2 years of age their venom has become essentially inactive. Phospholipase A2 is the most lethal of the honeybee venom peptides, whereas melittin, which is only slightly less lethal, is the most abundant. Concurrent analyses of melittin, phospholipase, and the combination of the two at their natural 3:1 mixture in bee venom revealed that the lethal activity of the mixture was about the same as native honeybee venom. This value was less than that for either melittin or phospholipase alone and indicates that synergism of the two peptides is not occurring. The results are consistent with independent lethal activities for the venom components, and show that melittin is not only the dominant, but also the main lethal component in honeybee venom.

Subsequent insect stings in children with hypersensitivity to Hymenoptera

To investigate the risk of life-threatening reactions to future stings, we sequentially challenged 113 children (aged 2 to 17 years) allergic to insect stings with a sting by the relevant insect. The time interval between the challenges varied from 2 to 6 weeks. The history of the index stings was a large local reaction (LR) in 16% and a systemic reaction (SR) in 84% of the test subjects. On the first challenge, 76% had a normal LR, 11% a large LR, and 13% an SR. On the second challenge, 78% of the children had a normal LR, 5% a large LR, and 17% an SR. Thirty-nine of the untreated children were exposed to a field sting during the subsequent 3-year follow-up period. In comparison with other diagnostic evaluations such as skin-prick tests, determinations of specific IgE and IgG antibodies, and single-sting exposure, the dual sting challenge scheme appears to be the best predictor of reactions to subsequent stings. It also appears to be helpful in selecting patients with an uncertain sensitization status for venom immunotherapy.

Partial biochemical characterization of venom from the ant, Pseudomyrmex triplarinus

Venom from the ant, Pseudomyrmex triplarinus, contains 12 proteins with mol. wts of > 100,000-4200, and they constitute 41.5% of the dry weight. In comparison with published data on ant, wasp, and bee venoms, whole venom has intense phospholipase activity and intermediate hemolytic activity. Four major proteins were isolated and purified by low pressure chromatography. The most abundant protein had a mol. wt of 4200 and weak hemolytic activity. The second most common protein was 20,400 and had phospholipase A2 activity. The other two major proteins had mol. wts of 24,500 and 14,100 and both exhibited phospholipase and direct hemolytic activities. There are eight minor proteins (> 100,000-40,000), each present at about 1% or less of the total protein. Assayed as a mixture, they had hyaluronidase activity. Seventeen free amino acids were detected with aspartic acid, glutamic acid, and proline together making up 72% of the total mass of amino acids. Glycerol was present at a concentration of 3.1% of the dry weight and the venom was devoid of lipids.