Venom Secretion Research Articles

Exaptation of an evolutionary constraint enables behavioural control over the composition of secreted venom in a giant centipede.

Venoms are biochemical arsenals that have emerged in numerous animal lineages, where they have co-evolved with morphological and behavioural traits for venom production and delivery. In centipedes, venom evolution is thought to be constrained by the morphological complexity of their venom glands due to physiological limitations on the number of toxins produced by their secretory cells. Here we show that the uneven toxin expression that results from these limitations have enabled Scolopendra morsitans to regulate the composition of their secreted venom despite the lack of gross morphologically complex venom glands. We show that this control is probably achieved by a combination of this heterogenous toxin distribution with a dual mechanism of venom secretion that involves neuromuscular innervation as well as stimulation via neurotransmitters. Our results suggest that behavioural control over venom composition may be an overlooked aspect of venom biology and provide an example of how exaptation can facilitate evolutionary innovation and novelty.

Blue-ringed octopus-inspired microneedle patch for robust tissue surface adhesion and active injection drug delivery.

Intratissue topical medication is important for the treatment of cutaneous, mucosal or splanchnic diseases. However, penetrating surface barriers to providing adequate and controllable drug delivery while guaranteeing adhesion in bodily fluids remains challenging. Here, the predatory behavior of the blue-ringed octopus inspired us with a strategy to improve topical medication. For effective intratissue drug delivery, the active injection microneedles were prepared in a manner inspired by the teeth and venom secretion of blue-ringed octopus. With on demand release function guided by temperature-sensitive hydrophobic and shrinkage variations, these microneedles can supply adequate drug delivery at an early stage and then achieve the long-term release stage. Meanwhile, the bionic suction cups were developed to facilitate microneedles to stay firmly in place (>10 kilopascal) when wet. With wet bonding ability and multiple delivery mode, this microneedle patch achieved satisfactory efficacy, such as accelerating the ulcers' healing speed or halting early tumor progression.

Fire ants feed their nestmates with their own venom

Venom secretion is widely used by ants for disease control and more generally as an external surface disinfectant. Here we report evidence that Solenopsis invicta feed their nestmates with their own venom. Venom alkaloids were found in crops and midguts of ants at concentration levels that have previously been reported as effective against various pathogens. These venom alkaloids were found in midguts of the larvae, indicating that trophallaxis must be involved in the transfer of venom, since larvae do not produce alkaloids and they depend on workers to be fed. After the mating flight, the female alates shed their wings, burrow into the soil, and start new colonies. The new queen provided alkaloids to her first batch of larvae in the new colony. Since the crops of female alates contain venom alkaloids donated from their nestmate workers, the transfer of worker alkaloids to new generation occurred. After minim adult workers emerged, they took the role in providing venom to the larvae in the colony. Minim adult workers eventually died out and the normal workers became the venom donors in the colony. Although other functions may be possible, considering the well-known antimicrobial property of venom alkaloids and their detected concentration levels, venom in the digestive system is most likely used as an internal antibiotic by fire ants.

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.

An investigation into the toxicity of tissue extracts from two distinct marine Polychaeta.

The present study investigated the potential toxicity of venomous secretions of two polychaetes, Hediste diversicolor and Glycera alba (Annelida: Phyllodocida). Toxic activity of putative toxins, measured on mussel gills through the Comet assay, revealed higher effects caused by extracts from H. diversicolor skin and G. alba specialised, jawed proboscis, when compared to control. The results suggest that H. diversicolor secretes toxins via skin for protection against predators, contrarily to G. alba, who secretes toxins for predation.

The rapid development of the first instar telson with venom secretion highlights the remarkable survival ability of scorpions

The scorpion venom system plays a critical role in capturing prey and defending against predators. In this study, the rapid developmental process of the first instar telson was first presented. The small amount of venom in the first instar could be stored well by the distorted and blocked venom ducts, which disappeared in the older scorpions. This special developmental process of the first instar telson revealed the notable survival ability of scorpions.

P–801 Effects of Lonomia obliqua venom components on human endometrial stromal cells: A potential source for new cytoprotective biomolecules against recurrent pregnancy loss

Abstract Study question Could new molecules like Lonomia obliqua lipocalins and hemolins have cytoprotective effects on endometrial stem cells (hESC)? Summary answer Lonomia obliqua venom-induced hESC viability, proliferation and migration occurred mainly by protection against oxidative damage and ERK-dependent pathway activation What is known already Recurrent pregnancy loss (RPL) is associated with severe physical and psychological morbidity, for which there is no treatment options. The pathophysiology involves deficiency in proliferation and migration capacities of endometrial stromal cells (hESCs) impairing embryo implantation and development. Animal venoms are rich sources of bioactive molecules and despite its known toxic effects, they also have protective components such as pro-proliferative molecules, growth factor-like, anti-apoptotic and anti-oxidant. Study design, size, duration This study was an experimental in vitro with endometrial stem cells. Treatment duration was 8–72h. Every assay had control cells exposed to phosphate buffered saline (PBS). Participants/materials, setting, methods hESCs were isolated from fresh human endometrial biopsies and characterized according standard protocols. Then the effects of L. obliqua venomous secretions on cell viability, proliferation and migration were determined using MTT, wound-healing assay, sulforhodamine B (SRB) assay and measuring the immunocontent of Ki67. Venom components involved in cell enhancing effects were also identified by classical chromatographic methods and proteomic analysis. Assays were conducted in triplicate. Main results and the role of chance The hESCs in culture showed adhesiveness properties, presented a fusiform fibroblastoid morphology and ability to in vitro differentiate into adipocytes, osteocytes and chondrocytes. The expression of cell surface markers was also characterized by flow cytometry. hESCs were positive for mesenchymal markers (CD105, CD90 and CD73) and negative for hematopoietic markers (CD45 and CD11), indicating that isolated cells have potential for multilineage differentiation. L. obliqua bristle extract (LOBE) increased dose-dependently hESCs viability in a concentration range varying from 0.001 to 0.1 µg/mL, independently of the cell isolation bath. For some cell isolates (patient ID 1, 3, 4, 6 and 7) it was observed a slightly reduction in hESC viability at highest LOBE concentrations (10 µg/mL). Treatment increased hESC viability in the presence of low concentrations of fetal bovine serum (1% FBS) and even in its complete absence. This effect was long lasting, being significant up to 72 h of incubation with LOBE in serum deprivation conditions. r to identify the potential molecules involved in the cytoprotective action, a mass spectrometry-based proteomic analysis was performed. It was identified a total number of 430 proteins in LOBE and 312 proteins in L. obliqua hemolymph. Limitations, reasons for caution This study was only conducted in vitro. Wider implications of the findings: In this work we reported the identification of at least six protein classes with cytoprotective properties through proteomic analysis and isolated one fraction enriched in this cytoprotective factors. L. obliqua secretions induced increase in hESCs viability, proliferation and migration mainly by the protection against oxidative damage and ERK-dependent pathway activation. Trial registration number Not applicable

Ancestral Reconstruction of Diet and Fang Condition in the Lamprophiidae: Implications for the Evolution of Venom Systems in Snakes

The Colubroidea includes all venomous and some nonvenomous snakes, many of which have extraordinary dental morphology and functional capabilities. It has been proposed that the ancestral condition of the Colubroidea is venomous with tubular fangs. The venom system includes the production of venomous secretions by labial glands in the mouth and usually includes fangs for effective delivery of venom. Despite significant research on the evolution of the venom system in snakes, limited research exists on the driving forces for different fang and dental morphology at a broader phylogenetic scale. We assessed the patterns of fang and dental condition in the Lamprophiidae, a speciose family of advanced snakes within the Colubroidea, and we related fang and dental condition to diet. The Lamprophiidae is the only snake family that includes front-fanged, rear-fanged, and fangless species. We produced an ancestral reconstruction for the family and investigated the pattern of diet and fangs within the clade. We concluded that the ancestral lamprophiid was most likely rear-fanged and that the shift in dental morphology was associated with changes in diet. This pattern indicates that fang loss, and probably venom loss, has occurred multiple times within the Lamprophiidae. There is also evidence that front fangs arose from a rear-fanged condition, and this has occurred independently more than once within the family. Our findings provide insight into fang and dental condition in relation to diet and support the hypothesis of a venomous ancestor for the Lamprophiidae.

In Vitro Studies for the Evaluation of Insecticidal Potential of the Venom of Endoparasitic Wasp Aenasius arizonensis (Girault) (Hymenoptera, Encyrtidae)

Aenasius arizonensis (Hymenoptera: Encyrtidae) a nymphal, solitary endoparasitoid is a potent biocontrol agent of cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae). Female wasp injects a blend of secretions in its host during parasitization which alters the host physiology. Insecticidal potential of crude venom of A. arizonensis was evaluated along with its chromatographic fractions by microinjections bioassays in its natural host insect P. solenopsis at 3rd nymphal instars and adult. Host insects were treated with two different volumes of crude venom (0.3 and 0.5 µL) and RP-HPLC fractions of venom, while host insects with saline injections were used as control. Biological activity of the crude venom was also evaluated after heat and protease treatment. Maximum mortality (84.0 ± 2.91) of the host insects was observed at highest dose rate (0.5 µL) of the crude venom; while lowest mortality (71.0 ± 2.31) was recorded at lowest dose (0.3 µL) of venom applied on 3rd instar life stage. On the other hand, significant difference in mortality of four peaks of RP-HPLC venom fractions were recorded against 3rd instar larvae and adult when microinjections containing crude venom and fractionated venom. Our data confirms that crude venom of the wasp induces significant mortality against its host P. solenopsis. Whereas, no significant difference in mortality was observed for heat and protease treated venom, suggesting that bioactive component of the venom secretions of the wasp are proteins in nature, which lost their biological activity upon heat and protease treatments.

Venom gland transcriptome from Heloderma horridum horridum by high-throughput sequencing

Lizards of the Helodermatidae (Anguimorpha) family consist of at least two well recognized species: Heloderma horridum horridum and Heloderma suspectum suspectum. They contain specialized glands in their jaws that produce venomous secretions that causes envenoming symptoms to bitten animals. One way to study proteins from such secretions is by RNA-seq; a powerful molecular tool to characterize the transcriptome of such specialized gland, and its protein secretions. The total RNA from venom gland tissues of H. horridum horridum was extracted and a cDNA library was constructed and sequenced. Overall, 114,172 transcripts were found, and 199 were annotated based on sequence similarities to previously described peptides/proteins. Transcripts coding for putative exendins, defensins, natriuretics and serine protease inhibitors were the most highly expressed. Transcripts that code for several putative serine proteases, phospholipases, metalloproteases, lipases, L-amino oxidase and nucleases were also found. Some of the novel identified transcripts were translationally controlled tumor proteins, venom factors, vespryns, waprins, lectins, cystatins and serine protease inhibitors. All these new protein structures may contribute to a better understanding of the venomous secretions of the Helodermatidae family.

Aphidius ervi Teratocytes Release Enolase and Fatty Acid Binding Protein Through Exosomal Vesicles.

The molecular bases of the host-parasitoid interactions in the biological system Acyrthosiphon pisum (Harris) (Homoptera, Aphididae) and Aphidius ervi (Haliday) (Hymenoptera, Braconidae) have been elucidated allowing the identification of a gamma-glutamyl transpeptidase, the active component of maternal venom secretion, and teratocytes, the embryonic parasitic factors responsible for host physiology regulation after parasitization. Teratocytes, cells deriving from the dissociation of the serosa, the parasitoid embryonic membrane, are responsible for extra-oral digestion of host tissues in order to provide a suitable nutritional environment for the development of parasitoid larvae. Teratocytes rapidly grow in size without undergoing any cell division, synthesize, and release in the host hemolymph two proteins: a fatty acid binding protein (Ae-FABP) and an enolase (Ae-ENO). Ae-FABP is involved in transport of fatty acids deriving from host tissues to the parasitoid larva. Ae-ENO is an extracellular glycolytic enzyme that functions as a plasminogen like receptor inducing its activation to plasmin. Both Ae-FABP and Ae-ENO lack their signal peptides, and they are released in the extracellular environment through an unknown secretion pathway. Here, we investigated the unconventional mechanism by which teratocytes release Ae-FABP and Ae-ENO in the extracellular space. Our results, obtained using immunogold staining coupled with TEM and western blot analyses, show that these two proteins are localized in vesicles released by teratocytes. The specific dimension of these vesicles and the immunodetection of ALIX and HSP70, two exosome markers, strongly support the hypothesis that these vesicles are exosomes.

Biochemical Modulation of Venom by Spiders is Achieved Via Compartmentalized Toxin Production and Storage

Animal venoms are complex chemical arsenals containing hundreds or even thousands of diverse small molecules, peptides, and proteins that affect a myriad of molecular targets. Because this biochemical arsenal is metabolically expensive, venom must be used sparingly and therefore one might predict that venom evolution would result in retention of only the most essential toxins for predation and/or defence. However, this presents a strong dichotomy in the functional requirements of venoms that are used for both predation and defence, which results in extensive functional redundancy. Here we show that spiders can overcome this potential metabolic burden by modulating the biochemical composition of their venom. We demonstrate that the venom peptidome of the lethal Australian funnel-web spider Hadronyche infensa changes both qualitatively and quantitatively throughout a series of defensive secretions — secretion of the most potent insecticidal toxins is preceded by secretion of non-insecticidal, presumably defensive, toxins. Using mass spectrometry imaging, we show that modulation of toxin secretion is facilitated by differential storage of toxins in the venom gland. We propose that the establishment of distinct venom-gland zipcodes for toxin production is an adaptation that reduces the metabolic expense of venom production and perhaps also serves to minimize effects from development of toxin resistance during predator-prey co-evolution. Our results highlight the importance of considering behavioral aspects of natural venom secretions in understanding toxin function and evolution.

Comparative analysis of intestinal bacteria among venom secretion and non-secrection snakes

To further investigate the bacterial community and identify the bacterial biomarkers between venom secretion and non-venom secretion snakes, 50 intestinal samples (25 large intestine, 25 small intestine) were obtained from 29 snakes (13 gut samples from Deinagkistrodon, 26 from Naja and 11 from Ptyas mucosa). 16S rDNA high-throughput sequencing results showed that 29 bacterial phyla, 545 bacterial genera, and 1,725 OTUs (operational taxonomic units) were identified in these samples. OTU numbers and the Ace, Chao, Shannon, and Simpson indexes were very similar among the three breeds of snakes included in this study. The Bacteroidetes, Firmicutes, Fusobacteria and Proteobacteria were predominant bacterial phyla. The relative abundance at the phylum level among these samples was similar, and the difference between small and large intestinal samples was not obvious. However, at the genus level, venom secretion snakes Deinagkistrodon and Naja clustered together according to different breeds. 27, 24, and 16 genera were identified as core microbes for Deinagkistrodon, Naja, and Ptyas mucosa, respectively. Interestingly, the relative abundances of genera Hafnia_Obesumbacterium, Providencia, and Ureaplasma were found to be significantly higher in non-venom secretion snakes, and the genera Achromobacter, Cetobacterium, Clostridium innocuum group, Fusobacterium, Lachnoclostridium, Parabacteroides, and Romboutsia were only detected in venom secretion snakes. The function of these bacteria in venom secretion needs to be further studied, and these venom secretion related genera may be the promising target to improve venom production.

Venom in Furs: Facial Masks as Aposematic Signals in a Venomous Mammal.

The function of colouration in animals includes concealment, communication and signaling, such as the use of aposematism as a warning signal. Aposematism is unusual in mammals, and exceptions help us to understand its ecology and evolution. The Javan slow loris is a highly territorial venomous mammal that has a distinctive facial mask and monochromatic vision. To help understand if they use aposematism to advertise their venom to conspecifics or predators with different visual systems, we studied a population in Java, Indonesia. Using ImageJ, we selected colours from the facial masks of 58 individuals, converted RBG colours into monochromatic, dichromatic and trichromatic modes, and created a contrast index. During 290 captures, we recorded venom secretion and aggressiveness. Using Non-metric Multidimensional Scaling and generalised additive models for location, scale and shape, we found that young slow lorises differ significantly from adults, being both more contrasting and more aggressive, with aggressive animals showing fewer wounds. We suggest aposematic facial masks serve multiple purposes in slow lorises based on age. Change in colouration through development may play a role in intraspecific competition, and advertise toxicity or aggressiveness to competitors and/or predators in juveniles. Aposematic signals combined with intraspecific competition may provide clues to new venomous taxa among mammals.

Secreted Cysteine-Rich Repeat Proteins "SCREPs": A Novel Multi-Domain Architecture.

Peptide toxins isolated from animal venom secretions have proven to be useful pharmacological tools for probing the structure and function of a number of molecular receptors. Their molecular structures are stabilized by posttranslational formation of multiple disulfide bonds formed between sidechain thiols of cysteine residues, resulting in high thermal and chemical stability. Many of these peptides have been found to be potent modulators of ion channels, making them particularly influential in this field. Recently, several peptide toxins have been described that have an unusual tandem repeat organization, while also eliciting a unique pharmacological response toward ion channels. Most of these are two-domain peptide toxins from spider venoms, such as the double-knot toxin (DkTx), isolated from the Earth Tiger tarantula (Haplopelma schmidti). The unusual pharmacology of DkTx is its high avidity for its receptor (TRPV1), a property that has been attributed to a bivalent mode-of-action. DkTx has subsequently proven a powerful tool for elucidating the structural basis for the function of the TRPV1 channel. Interestingly, all tandem repeat peptides functionally characterized to date share this high avidity to their respective binding targets, suggesting they comprise an unrecognized structural class of peptides with unique structural features that result in a characteristic set of pharmacological properties. In this article, we explore the prevalence of this emerging class of peptides, which we have named Secreted, Cysteine-rich REpeat Peptides, or “SCREPs.” To achieve this, we have employed data mining techniques to extract SCREP-like sequences from the UniProtKB database, yielding approximately sixty thousand candidates. These results indicate that SCREPs exist within a diverse range of species with greatly varying sizes and predicted fold types, and likely include peptides with novel structures and unique modes of action. We present our approach to mining this database for discovery of novel ion-channel modulators and discuss a number of “hits” as promising leads for further investigation. Our database of SCREPs thus constitutes a novel resource for biodiscovery and highlights the value of a data-driven approach to the identification of new bioactive pharmacological tools and therapeutic lead molecules.

Beach to Bench to Bedside: Marine Invertebrate Biochemical Adaptations and Their Applications in Biotechnology and Biomedicine.

The ocean covers more than 70% of the surface of the planet and harbors very diverse ecosystems ranging from tropical coral reefs to the deepest ocean trenches, with some of the most extreme conditions of pressure, temperature, and light. Organisms living in these environments have been subjected to strong selective pressures through millions of years of evolution, resulting in a plethora of remarkable adaptations that serve a variety of vital functions. Some of these adaptations, including venomous secretions and light-emitting compounds or ink, represent biochemical innovations in which marine invertebrates have developed novel and unique bioactive compounds with enormous potential for basic and applied research. Marine biotechnology, defined as the application of science and technology to marine organisms for the production of knowledge, goods, and services, can harness the enormous possibilities of these unique bioactive compounds acting as a bridge between biological knowledge and applications. This chapter highlights some of the most exceptional biochemical adaptions found specifically in marine invertebrates and describes the biotechnological and biomedical applications derived from them to improve the quality of human life.

Comparison of biochemical and cytotoxic activities of extracts obtained from dorsal spines and caudal fin of adult and juvenile non-native Caribbean lionfish (Pterois volitans/miles)

Pterois volitans/miles lionfish (adult and juvenile) dorsal spines and caudal fin extracts were compared in their general composition, enzymatic activities and hemolytic and cytotoxic effects on bovine aortic endothelial cells and murine myoblasts, to distinguish between the activities present in the venom and epidermal mucus. Intradermal and intramuscular injections were also administered in mice to determine in vivo effects.This work shows that crude venom of Caribbean species of lionfish, present in dorsal spines, induces several in vitro effects including hemolysis, weak cytotoxicity, proteolytic and hyaluronidase activities, whereas in vivo, it is not hemorrhagic nor myotoxic, but causes edema, plasma extravasation and a thrombotic-associated lesion on the skin. Some small differences were observed between adult and juvenile venomous secretions. Gelatinolytic activity of the epidermal mucus, the only activity found in caudal fin extracts, could contribute to the in vivo toxicity of the venom.

Scorpion venoms in gastric cancer.

Venom secretions from snakes, scorpions, spiders and bees, have been widely applied in traditional medicine and current biopharmaceutical research. Possession of anticancer potential is another novel discovery for animal venoms and toxins. An increasing number of studies have shown the anticancer effects of venoms and toxins of snakes, and scorpions in vitro and in vivo, which were achieved mainly through the inhibition of cancer growth, arrest of cell cycle, induction of apoptosis and suppression of cancer metastasis. However, more evidence is needed to support this concept and the mechanisms of anticancer actions are not clearly understood. The present review is focused on the recant updates on anticancer venom research.

The Biochemical Toxin Arsenal from Ant Venoms.

Ants (Formicidae) represent a taxonomically diverse group of hymenopterans with over 13,000 extant species, the majority of which inject or spray secretions from a venom gland. The evolutionary success of ants is mostly due to their unique eusociality that has permitted them to develop complex collaborative strategies, partly involving their venom secretions, to defend their nest against predators, microbial pathogens, ant competitors, and to hunt prey. Activities of ant venom include paralytic, cytolytic, haemolytic, allergenic, pro-inflammatory, insecticidal, antimicrobial, and pain-producing pharmacologic activities, while non-toxic functions include roles in chemical communication involving trail and sex pheromones, deterrents, and aggregators. While these diverse activities in ant venoms have until now been largely understudied due to the small venom yield from ants, modern analytical and venomic techniques are beginning to reveal the diversity of toxin structure and function. As such, ant venoms are distinct from other venomous animals, not only rich in linear, dimeric and disulfide-bonded peptides and bioactive proteins, but also other volatile and non-volatile compounds such as alkaloids and hydrocarbons. The present review details the unique structures and pharmacologies of known ant venom proteinaceous and alkaloidal toxins and their potential as a source of novel bioinsecticides and therapeutic agents.

Multifunctional warheads: Diversification of the toxin arsenal of centipedes via novel multidomain transcripts

Arthropod toxins are almost invariably encoded by transcripts encoding prepropeptides that are posttranslationally processed to yield a single mature toxin. In striking contrast to this paradigm, we used a complementary transcriptomic, proteomic and MALDI-imaging approach to identify four classes of multidomain centipede-toxin transcripts that each encodes multiple mature toxins. These multifunctional warheads comprise either: (1) repeats of linear peptides; (2) linear peptides preceding cysteine-rich peptides; (3) cysteine-rich peptides preceding linear peptides; or (4) repeats of linear peptides preceding cysteine-rich peptides. MALDI imaging of centipede venom glands revealed that these peptides are posttranslationally liberated from the original gene product in the venom gland and not by proteases following venom secretion. These multidomain transcripts exhibit a remarkable conservation of coding sequences, in striking contrast to monodomain toxin transcripts from related centipede species, and we demonstrate that they represent a rare class of predatory toxins that have evolved under strong negative selection. We hypothesize that the peptide toxins liberated from multidomain precursors might have synergistic modes of action, thereby allowing negative selection to dominate as the toxins encoded by the same transcript become increasingly interdependent. These results have direct implications for understanding the evolution of centipede venoms, and highlight the importance of taking a multidisciplinary approach for the investigation of novel venoms. The potential synergistic actions of the mature peptides are also of relevance to the growing biodiscovery efforts aimed at centipede venom. We also demonstrate the application of MALDI imaging in providing a greater understanding of toxin production in venom glands. This is the first MALDI imaging data of any venom gland.