Venom effects on monoaminergic systems

Metatranscriptome analysis reveals the putative venom toxin repertoire of the biofouling hydroid Ectopleura larynx

Cnidarians thriving in biofouling communities on aquaculture net pens represent a significant health risk for farmed finfish due to their stinging cells. The toxins coming into contact with the fish, during net cleaning, can adversely affect their behavior, welfare, and survival, with a particularly serious health risk for the gills, causing direct tissue damage such as formation of thrombi and increasing risks of secondary infections. The hydroid Ectopleura larynx is one of the most common fouling organisms in Northern Europe. However, despite its significant economic, environmental, and operational impact on finfish aquaculture, biological information on this species is scarce and its venom composition has never been investigated. In this study, we generated a whole transcriptome of E. larynx, and identified its putative expressed venom toxin proteins (predicted toxin proteins, not functionally characterized) based on in silico transcriptome annotation mining and protein sequence analysis. The results uncovered a broad and diverse repertoire of putative toxin proteins for this hydroid species. Its toxic arsenal appears to include a wide and complex selection of toxin proteins, covering a large panel of potential biological functions that play important roles in envenomation. The putative toxins identified in this species, such as neurotoxins, GTPase toxins, metalloprotease toxins, ion channel impairing toxins, hemorrhagic toxins, serine protease toxins, phospholipase toxins, pore-forming toxins, and multifunction toxins may cause various major deleterious effects in prey, predators, and competitors. These results provide valuable new insights into the venom composition of cnidarians, and venomous marine organisms in general, and offer new opportunities for further research into novel and valuable bioactive molecules for medicine, agronomics and biotechnology.

Indolealkylamines in the venom of the scorpion Thorellius intrepidus

Scorpions are a group of arthropods that strike fear in many people due to their severe medical symptoms, even death, caused by their venomous stings. Even so, not all scorpion species contain harmful venoms against humans but still have valuable bioactive molecules, which could be used in developing new pharmaceutical leads for treating important diseases. This work conducted a comprehensive analysis of the venom from the scorpion Thorellius intrepidus. The venom of T. intrepidus was separated by size exclusion chromatography, and four main fractions were obtained. Fraction IV (FIV) contained small molecules representing over 90% of the total absorbance at 280 nm. Analysis of fraction FIV by RP-HPLC indicated the presence of three main molecules (FIV.1, FIV.2, and FIV.3) with similar UV absorbance spectra profiles. The molecular masses of FIV.1, FIV.2, and FIV.3 were determined, resulting in 175.99, 190.07, and 218.16 Da, respectively. Further confirmation through 1H-NMR and 13C-NMR analyses revealed that these molecules were serotonin, N-methylserotonin, and bufotenidine. These intriguing compounds are speculated to play a pivotal role in self-defense and increasing venom toxicity and could also offer promising biotechnological applications as small bioactive molecules.

Tako-tsubo cardiomyopathy in clinical toxinology: A systematic review

Tako-tsubo cardiomyopathy (TTC) is a transient left ventricular dysfunction, normally triggered by emotional or physical stress, although it is also associated with to use of drugs, drug abuse, or some intoxications. In addition, TTC has been reported in some case reports derived from the exposure of patients to animal venoms, toxins or poisons, or bacterial infections. However, to date, a systematic assessment of TTC in clinical toxinology is lacking. Therefore the aim of this study was to collect and integrate the available information about TTC in clinical toxinology. After our search strategy, 19 articles were retrieved, resulting in 20 case reports. Most cases occurred in women (75.0%). The venomous species that trigger TTC are bee/wasp, including probable Africanized honey bee and Vespa orientalis (15.0%), scorpions (Tytius serrulatus and Androctonus australis, 15.0%), a spider (Latrodectus tredecimguttatus, 5.0%), snakes (Gloydius blomhofii and Naja nivea, 10.0%), Clostridium sp (C. tetani, C. botulinum and C. difficile, 45.0%) and jellyfish (Pelagia noctiluca and Carukia barnesi, 10.0%). Among the affected people there were two deaths. In all case reports authors diagnosed TTC by using the combination of some of the following strategies: clinical findings, echocardiography, magnetic cardiac resonance, electrocardiogram changes and/or the increased plasma levels of cardiac damage biomarkers. In most cases images were available. We hypothesized the possible mode of action of venoms, toxins or poisons to induce TTC, however other mechanisms may exist, but they have not been described yet. Therefore, further studies are needed. In some cases, venoms, toxins, or poisons might cause catecholamine discharge either directly or indirectly, therefore, this was suggested as the trigger of TTC. Finally, the appearance of TTC should be considered in clinical toxinology.

Dopaminergic metabolism is affected by intracerebral injection of Tb II-I isolated from Tityus bahiensis scorpion venom

Tb II-I isolated from Tityus bahiensis venom causes epileptic-discharges when injected into the hippocampus of rats. The involvement of neurotransmitters in this activity was investigated. Our results demonstrated that Tb II-I increases the concentrations of dopamine metabolite but does not alter other neurotransmitters. Thus, dopaminergic system seems to be partially responsible for the convulsive process. Specific action on particular neurotransmitter can make this toxin a useful tool to better understand the functioning of the system.

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The dopaminergic system is affected by intracerebral injection of Tb II-I

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The dopaminergic system seems to be partially responsible for the convulsive process.

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The hippocampal level of glutamate and GABA is not affected by Tb II-I

Transcriptomic Analysis of the Venom Gland and Enzymatic Characterization of the Venom of Phoneutria depilata (Ctenidae) from Colombia

The transcriptome of the venom glands of the Phoneutria depilata spider was analyzed using RNA-seq with an Illumina protocol, which yielded 86,424 assembled transcripts. A total of 682 transcripts were identified as potentially coding for venom components. Most of the transcripts found were neurotoxins (156) that commonly act on sodium and calcium channels. Nevertheless, transcripts coding for some enzymes (239), growth factors (48), clotting factors (6), and a diuretic hormone (1) were found, which have not been described in this spider genus. Furthermore, an enzymatic characterization of the venom of P. depilata was performed, and the proteomic analysis showed a correlation between active protein bands and protein sequences found in the transcriptome. The transcriptomic analysis of P. depilata venom glands show a deeper description of its protein components, allowing the identification of novel molecules that could lead to the treatment of human diseases, or could be models for developing bioinsecticides.

Stingray Venom Proteins: Mechanisms of Action Revealed Using a Novel Network Pharmacology Approach

Animal venoms offer a valuable source of potent new drug leads, but their mechanisms of action are largely unknown. We therefore developed a novel network pharmacology approach based on multi-omics functional data integration to predict how stingray venom disrupts the physiological systems of target animals. We integrated 10 million transcripts from five stingray venom transcriptomes and 848,640 records from three high-content venom bioactivity datasets into a large functional data network. The network featured 216 signaling pathways, 29 of which were shared and targeted by 70 transcripts and 70 bioactivity hits. The network revealed clusters for single envenomation outcomes, such as pain, cardiotoxicity and hemorrhage. We carried out a detailed analysis of the pain cluster representing a primary envenomation symptom, revealing bibrotoxin and cholecystotoxin-like transcripts encoding pain-inducing candidate proteins in stingray venom. The cluster also suggested that such pain-inducing toxins primarily activate the inositol-3-phosphate receptor cascade, inducing intracellular calcium release. We also found strong evidence for synergistic activity among these candidates, with nerve growth factors cooperating with the most abundant translationally-controlled tumor proteins to activate pain signaling pathways. Our network pharmacology approach, here applied to stingray venom, can be used as a template for drug discovery in neglected venomous species.

Pain-related toxins in scorpion and spider venoms: a face to face with ion channels

Pain is a common symptom induced during envenomation by spiders and scorpions. Toxins isolated from their venom have become essential tools for studying the functioning and physiopathological role of ion channels, as they modulate their activity. In particular, toxins that induce pain relief effects can serve as a molecular basis for the development of future analgesics in humans. This review provides a summary of the different scorpion and spider toxins that directly interact with pain-related ion channels, with inhibitory or stimulatory effects. Some of these toxins were shown to affect pain modalities in different animal models providing information on the role played by these channels in the pain process. The close interaction of certain gating-modifier toxins with membrane phospholipids close to ion channels is examined along with molecular approaches to improve selectivity, affinity or bioavailability in vivo for therapeutic purposes.

Mast Cells in Inflammation and Disease: Recent Progress and Ongoing Concerns

Mast cells have existed long before the development of adaptive immunity, although they have been given different names. Thus, in the marine urochordate Styela plicata, they have been designated as test cells. However, based on their morphological characteristics (including prominent cytoplasmic granules) and mediator content (including heparin, histamine, and neutral proteases), test cells are thought to represent members of the lineage known in vertebrates as mast cells. So this lineage presumably had important functions that preceded the development of antibodies, including IgE. Yet mast cells are best known, in humans, as key sources of mediators responsible for acute allergic reactions, notably including anaphylaxis, a severe and potentially fatal IgE-dependent immediate hypersensitivity reaction to apparently harmless antigens, including many found in foods and medicines. In this review, we briefly describe the origins of tissue mast cells and outline evidence that these cells can have beneficial as well as detrimental functions, both innately and as participants in adaptive immune responses. We also discuss aspects of mast cell heterogeneity and comment on how the plasticity of this lineage may provide insight into its roles in health and disease. Finally, we consider some currently open questions that are yet unresolved.

Lesser weever fish (Echiichthys vipera Cuvier, 1829) venom is cardiotoxic but not haemorrhagic

Despite comprising over half of the biodiversity of living venomous vertebrates, fish venoms are comparatively understudied. Venom from the lesser weever fish (Echiichthys vipera syn. Trachinus vipera) has received only cursory attention despite containing one of the most potent venom toxins (trachinine). Literature records are further complicated by early studies combining the venom with that of the related greater weever (Trachinus draco). The current study used a chicken chorioallantoic membrane assay to investigate venom bioactivity following the application of measured quantities of crude venom to a major bilateral vein at 1 cm distance from the heart. The venom had a dose-dependent effect on survival rate and exhibited dose-dependent cardiotoxic properties at day six of development. Crude E. vipera triggered tachycardia at doses of 37.58 and 44.88 μg/μL and bradycardia at 77.4 μg/μL. The three highest doses (65.73, 77.4 and 151.24 μg/μL) caused significant mortality. These data also suggested intra-specific variation in E. vipera venom potency. Unlike a number of other piscine venoms, E. vipera venom was not haemorrhagic at the concentrations assayed.

Identification and quantification of honeybee venom constituents by multiplatform metabolomics

Honeybee (Apis mellifera) venom (HBV) has been a subject of extensive proteomics research; however, scarce information on its metabolite composition can be found in the literature. The aim of the study was to identify and quantify the metabolites present in HBV. To gain the highest metabolite coverage, three different mass spectrometry (MS)-based methodologies were applied. In the first step, untargeted metabolomics was used, which employed high-resolution, accurate-mass Orbitrap MS. It allowed obtaining a broad overview of HBV metabolic components. Then, two targeted metabolomics approaches, which employed triple quadrupole MS, were applied to quantify metabolites in HBV samples. The untargeted metabolomics not only confirmed the presence of amines, amino acids, carbohydrates, and organic acids in HBV, but also provided information on venom components from other metabolite classes (e.g., nucleosides, alcohols, purine and pyrimidine derivatives). The combination of three MS-based metabolomics platforms facilitated the identification of 214 metabolites in HBV samples, among which 138 were quantified. The obtaining of the wide free amino acid profiles of HBV is one of the project’s achievements. Our study contributed significantly to broadening the knowledge about HBV composition and should be continued to obtain the most comprehensive metabolite profile of HBV.

Novel components of Tityus serrulatus venom: A transcriptomic approach

Several research groups have studied the components produced by the venom gland of the scorpion Tityus serrulatus, which has one of the most lethal venoms in the world. Various methodologies have been employed to clarify the complex mechanisms of action of these components, especially neurotoxins and enzymes. Transcriptomes and proteomes have provided important information for pharmacological, biochemical, and immunological research. Next-generation sequencing (NGS) has allowed the description of new transcripts and completion of partial sequence descriptions for peptides, especially those with low expression levels. In the present work, after NGS sequencing, we searched for new putative venom components. We present a total of nine new transcripts with neurotoxic potential (Ts33-41) and describe the sequences of one hyaluronidase (TsHyal_4); three enzymes involved in amidation (peptidyl-glycine alpha-amidating monooxygenase A, peptidyl-alpha-hydroxyglycine alpha-amidating lyase, and peptidylglycine alpha-hydroxylating monooxygenase), which increases the lethal potential of neurotoxins; and also the enzyme Ts_Chitinase1, which may be involved in the venom's digestive action. In addition, we determined the level of transcription of five groups: toxins, metalloproteases, hyaluronidases, chitinases and amidation enzymes, including new components found in this study. Toxins are the predominant group with an expression level of 91.945%, followed by metalloproteases with only 7.790% and other groups representing 0.265%.

The venoms of the lesser (Echiichthys vipera) and greater (Trachinus draco) weever fish- A review

In comparison with other animal venoms, fish venoms remain relatively understudied. This is especially true for that of the lesser Echiichthys vipera and greater weever fish Trachinus draco which, apart from the isolation of their unique venom cytolysins, trachinine and dracotoxin, respectively, remain relatively uncharacterised. Envenomation reports mainly include mild symptoms consisting of nociception and inflammation. However, like most fish venoms, if the venom becomes systemic it causes cardiorespiratory and blood pressure changes. Although T. draco venom has not been studied since the 1990's, recent studies on E. vipera venom have discovered novel cytotoxic components on human cancer cells, but due to the scarcity of research on the molecular make-up of the venom, the molecule(s) causing this cytotoxicity remains unknown. This review analyses past studies on E. vipera and T. draco venom, the methods used in the , the venom constituents characterised, the reported symptoms of envenomation and compares these findings with those from other venomous Scorpaeniformes.

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Research on the weever fish venoms Echiichthys vipera and Trachinus draco has

been scarce.

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E. vipera and T. draco venoms elicit cardiorespiratory symptoms in victims.

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E. vipera and T. draco contain unique cytolysins – Trachinine and Dracotoxin.

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Dracotoxin is haemolytic and contains membrane depolarising activities.

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E. vipera venom triggers apoptosis in human colon carcinoma cells.

Asian hornet Vespa velutina nigrithorax venom: Evaluation and identification of the bioactive compound responsible for human keratinocyte protection against oxidative stress

The present study aimed to explore the potential antioxidant molecules of the Asian hornet venom (Vespa velutina nigrithorax) responsible for radical scavenging activity and human keratinocyte protection against oxidative stress. We developed a first technical platform that combined a DPPH radical scavenging chemical assay and cytotoxicity and ROS (reactive oxygen species) production in HaCaT keratinocyte cells exposed to UVB to evaluate the antioxidant property of V. velutina venom. We further employed Thin Layer Chromatography (TLC) combined with the DPPH assay as a targeted separation approach to isolate the antioxidant compounds responsible for the free radical scavenging property of V. velutina venom. In parallel, the latter was fractionated by a HPLC-DAD non-targeted separation approach. From this experiment, nine fractions were generated which were again evaluated separately for their antioxidant properties using DPPH assays. Results showed that only one fraction exhibited significant antioxidant activity in which serotonin was identified as the major compound by a UHPLC-ESI-QTOF HRMS/MS approach. We finally demonstrated, using purified serotonin molecule that this bioactive structure is mostly responsible for the free radical scavenging property of the crude venom as evidenced by DPPH and ROS assays in HaCaT cells exposed to UVB.

A population of descending tyraminergic/octopaminergic projection neurons of the insect deutocerebrum

In this study, we describe a cluster of tyraminergic/octopaminergic neurons in the lateral dorsal deutocerebrum of desert locusts (Schistocerca gregaria) with descending axons to the abdominal ganglia. In the locust, these neurons synthesize octopamine from tyramine stress-dependently. Electrophysiological recordings in locusts reveal that they respond to mechanosensory touch stimuli delivered to various parts of the body including the antennae. A similar cluster of tyraminergic/octopaminergic neurons was also identified in the American cockroach (Periplaneta americana) and the pink winged stick insect (Sipyloidea sipylus). It is suggested that these neurons release octopamine in the ventral nerve cord ganglia and, most likely, convey information on arousal and/or stressful stimuli to neuronal circuits thus contributing to the many actions of octopamine in the central nervous system.

Application of Metabolomic Tools for Studying Low Molecular-Weight Fraction of Animal Venoms and Poisons

Both venoms and poisonous secretions are complex mixtures that assist in defense, predation, communication, and competition in the animal world. They consist of variable bioactive molecules, such as proteins, peptides, salts and also metabolites. Metabolomics opens up new perspectives for the study of venoms and poisons as it gives an opportunity to investigate their previously unexplored low molecular-weight components. The aim of this article is to summarize the available literature where metabolomic technologies were used for examining the composition of animal venoms and poisons. The paper discusses only the low molecular-weight components of venoms and poisons collected from snakes, spiders, scorpions, toads, frogs, and ants. An overview is given of the analytical strategies used in the analysis of the metabolic content of the samples. We paid special attention to the classes of compounds identified in various venoms and poisons and potential applications of the small molecules (especially bufadienolides) discovered. The issues that should be more effectively addressed in the studies of animal venoms and poisons include challenges related to sample collection and preparation, species-related chemical diversity of compounds building the metabolome and a need of an online database that would enhance identification of small molecule components of these secretions.

Tick Paralysis: Solving an Enigma

In comparison to other arachnids, ticks are major vectors of disease, but less than 8% of the known species are capable of inducing paralysis, as compared to the ~99⁻100% arachnids that belong to venomous classes. When considering the potential monophyly of venomous Arachnida, this review reflects on the implications regarding the classification of ticks as venomous animals and the possible origin of toxins. The origin of tick toxins is compared with scorpion and spider toxins and venoms based on their significance, functionality, and structure in the search to find homologous venomous characters. Phenotypic evaluation of paralysis, as caused by different ticks, demonstrated the need for expansion on existing molecular data of pure isolated tick toxins because of differences and discrepancies in available data. The use of in-vivo, in-vitro, and in-silico assays for the purification and characterization of paralysis toxins were critically considered, in view of what may be considered to be a paralysis toxin. Purified toxins should exhibit physiologically relevant activity to distinguish them from other tick-derived proteins. A reductionist approach to identify defined tick proteins will remain as paramount in the search for defined anti-paralysis vaccines.

Possible complication of bee stings and a review of the cardiac effects of bee stings

We report the case of a patient who, ∼3 weeks after multiple bee stings, developed a prolonged heart block, syncope and cardiac arrest. This required a temporary pacemaker to be implanted, which was later replaced with a permanent pacemaker. An ECG taken following surgery for a fractured humerus 6 years earlier was reportedly normal. The patient had been a rubber tapper who walked ∼1.5 km/day, but after the bee attack he was no longer able to walk or get up from the bed without experiencing syncope. We presume that the bee venom caused these signs, as well as the resulting heart block, which persisted long after the bee sting had subsided. Since his coronary angiogram was normal we believe he had a Kounis type involvement of the cardiovascular system, namely profound coronary spasm that caused complete heart block that did not recover. Another probable reason for the complete heart block could have been that the bees had consumed the pollen of a rhododendron flower, causing 'grayanotoxin' poisoning and severe heart block. The other effects of bee sting are discussed briefly.

In vivo and real-time monitoring of secondary metabolites of living organisms by mass spectrometry

Secondary metabolites are compounds that are important for the survival and propagation of animals and plants. Our current understanding on the roles and secretion mechanism of secondary metabolites is limited by the existing techniques that typically cannot provide transient and dynamic information about the metabolic processes. In this manuscript, by detecting venoms secreted by living scorpion and toad upon attack and variation of alkaloids in living Catharanthus roseus upon stimulation, which represent three different sampling methods for living organisms, we demonstrated that in vivo and real-time monitoring of secondary metabolites released from living animals and plants could be readily achieved by using field-induced direct ionization mass spectrometry.

ADP is a vasodilator component from Lasiodora sp. mygalomorph spider venom

Members of the spider genus Lasiodora are widely distributed in Brazil, where they are commonly known as caranguejeiras. Lasiodora spider venom is slightly harmful to humans. The bite of this spider causes local pain, edema and erythema. However, Lasiodora sp. spider venom may be a source of important pharmacological tools. Our research group has described previously that Lasiodora sp. venom produces bradycardia in the isolated rat heart. In the present work, we sought to evaluate the vascular effect of Lasiodora sp. venom and to isolate the vasoactive compounds from the venom. The results showed that Lasiodora spider venom induced a concentration-dependent vasodilation in rat aortic rings, which was dependent on the presence of a functional endothelium and abolished by the nitric oxide synthase (NOS) inhibitor L-NAME. Western blot experiments revealed that the venom also increased endothelial NOS function by increasing phosphorylation of the Ser¹¹⁷⁷ residue. Assay-directed fractionation isolated a vasoactive fraction from Lasiodora sp. venom. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) assays identified a mixture of two compounds: adenosine diphosphate (ADP, approximately 90%) and adenosine monophosphate (AMP, approximately 10%). The vasodilator effects of Lasiodora sp. whole venom, as well as ADP, were significantly inhibited by suramin, which is a purinergic P2-receptor antagonist. Therefore, the results of the present work indicate that ADP is a main vasodilator component of Lasiodora sp. spider venom.

Parasites: evolution’s neurobiologists

For millions of years, parasites have altered the behaviour of their hosts. Parasites can affect host behaviour by: (1) interfering with the host’s normal immune–neural communication, (2) secreting substances that directly alter neuronal activity via non-genomic mechanisms and (3) inducing genomic- and/or proteomic-based changes in the brain of the host. Changes in host behaviour are often restricted to particular behaviours, with many other behaviours remaining unaffected. Neuroscientists can produce this degree of selectivity by targeting specific brain areas. Parasites, however, do not selectively attack discrete brain areas. Parasites typically induce a variety of effects in several parts of the brain. Parasitic manipulation of host behaviour evolved within the context of the manipulation of other host physiological systems (especially the immune system) that was required for a parasite’s survival. This starting point, coupled with the fortuitous nature of evolutionary innovation and evolutionary pressures to minimize the costs of parasitic manipulation, likely contributed to the complex and indirect nature of the mechanisms involved in host behavioural control. Because parasites and neuroscientists use different tactics to control behaviour, studying the methods used by parasites can provide novel insights into how nervous systems generate and regulate behaviour. Studying how parasites influence host behaviour will also help us integrate genomic, proteomic and neurophysiological perspectives on behaviour.

Conserved role of dopamine in the modulation of behavior

Dopamine is an ancient signaling molecule. It is responsible for maintaining the adaptability of behavioral outputs and is found across taxa. The following is a summary of the role of dopamine and the mechanisms of its function and dysfunction. We discuss our recent findings on dopaminergic control of behaviors in C. elegans and discuss its potential implications for work in the fields of C. elegans and Parkinson research.

Mast cell chymase reduces the toxicity of Gila monster venom, scorpion venom, and vasoactive intestinal polypeptide in mice

Mast cell degranulation is important in the pathogenesis of anaphylaxis and allergic disorders. Many animal venoms contain components that can induce mast cell degranulation, and this has been thought to contribute to the pathology and mortality caused by envenomation. However, we recently reported evidence that mast cells can enhance the resistance of mice to the venoms of certain snakes and that mouse mast cell-derived carboxypeptidase A3 (CPA3) can contribute to this effect. Here, we investigated whether mast cells can enhance resistance to the venom of the Gila monster, a toxic component of that venom (helodermin), and the structurally similar mammalian peptide, vasoactive intestinal polypeptide (VIP). Using 2 types of mast cell-deficient mice, as well as mice selectively lacking CPA3 activity or the chymase mouse mast cell protease-4 (MCPT4), we found that mast cells and MCPT4, which can degrade helodermin, can enhance host resistance to the toxicity of Gila monster venom. Mast cells and MCPT4 also can limit the toxicity associated with high concentrations of VIP and can reduce the morbidity and mortality induced by venoms from 2 species of scorpions. Our findings support the notion that mast cells can enhance innate defense by degradation of diverse animal toxins and that release of MCPT4, in addition to CPA3, can contribute to this mast cell function.

Brown spider (Loxosceles genus) venom toxins: tools for biological purposes

Venomous animals use their venoms as tools for defense or predation. These venoms are complex mixtures, mainly enriched of proteic toxins or peptides with several, and different, biological activities. In general, spider venom is rich in biologically active molecules that are useful in experimental protocols for pharmacology, biochemistry, cell biology and immunology, as well as putative tools for biotechnology and industries. Spider venoms have recently garnered much attention from several research groups worldwide. Brown spider (Loxosceles genus) venom is enriched in low molecular mass proteins (5–40 kDa). Although their venom is produced in minute volumes (a few microliters), and contain only tens of micrograms of protein, the use of techniques based on molecular biology and proteomic analysis has afforded rational projects in the area and permitted the discovery and identification of a great number of novel toxins. The brown spider phospholipase-D family is undoubtedly the most investigated and characterized, although other important toxins, such as low molecular mass insecticidal peptides, metalloproteases and hyaluronidases have also been identified and featured in literature. The molecular pathways of the action of these toxins have been reported and brought new insights in the field of biotechnology. Herein, we shall see how recent reports describing discoveries in the area of brown spider venom have expanded biotechnological uses of molecules identified in these venoms, with special emphasis on the construction of a cDNA library for venom glands, transcriptome analysis, proteomic projects, recombinant expression of different proteic toxins, and finally structural descriptions based on crystallography of toxins.

Pathological axes of wound repair: gastrulation revisited

Post-traumatic inflammation is formed by molecular and cellular complex mechanisms whose final goal seems to be injured tissue regeneration.

In the skin -an exterior organ of the body- mechanical or thermal injury induces the expression of different inflammatory phenotypes that resemble similar phenotypes expressed during embryo development. Particularly, molecular and cellular mechanisms involved in gastrulation return. This is a developmental phase that delineates the three embryonic germ layers: ectoderm, endoderm and mesoderm. Consequently, in the post-natal wounded skin, primitive functions related with the embryonic mesoderm, i.e. amniotic and yolk sac-derived, are expressed. Neurogenesis and hematogenesis stand out among the primitive function mechanisms involved.

Interestingly, in these phases of the inflammatory response, whose molecular and cellular mechanisms are considered as traces of the early phases of the embryonic development, the mast cell, a cell that is supposedly inflammatory, plays a key role.

The correlation that can be established between the embryonic and the inflammatory events suggests that the results obtained from the research regarding both great fields of knowledge must be interchangeable to obtain the maximum advantage.

Cardiovascular effects of scorpionfish (Scorpaena plumieri) venom

The aim of the present study was to investigate the cardiovascular activity of Scorpaena plumieri venom in both in vivo and in vitro models. In anesthetized rats, doses of the venom (14-216 microg protein/kg) induced a transient increase in the mean arterial pressure. However at higher dose (338 microg protein/kg) this effect was followed by a sudden hypotension and the animal evolved to death. The heart rate was temporarily increased and followed by bradycardia using doses > or =108 microg/kg. In isolated rat hearts the crude venom (5-80 microg protein) produced dose-dependent positive ventricular chronotropic, inotropic, lusitropic and coronary vasoconstriction responses. Partial purification of an active fraction (CF, cardiovascular fraction) which reproduced the cardiovascular effects induced by crude venom on isolated hearts was achieved by conventional gel filtration chromatography. Adrenergic blockades, prazosin and propranolol, significantly attenuated these responses. The coronary vasoconstriction response to CF was also attenuated by chemical endothelium denudation. In conclusion, the data showed that S. plumieri fish venom induces disorders in the cardiovascular system. It also suggests that alpha(1) and beta-adrenergic receptors, and the vascular endothelium, are involved at least partially, in these cardiac effects.

Mast cell functions in the innate skin immune system

Mast cells are not only potent effector cells in allergy, but are also important players in protective immune responses against pathogens. Most of our knowledge about mast cells in innate immunity is derived from models of sepsis, whereas their role in innate immune responses of the skin has largely been neglected in the past. Their particular pattern of distribution in the skin and their ability to sense and react to pathogens and other danger signals indicate that mast cells can be important sentinels and effector cells in skin immune responses. The recent findings reviewed here have confirmed this hypothesis and have established a prominent role for skin mast cells in innate immunity.

Mast cells in the promotion and limitation of chronic inflammation

Observations of increased numbers of mast cells at sites of chronic inflammation have been reported for over a hundred years. Light and electron microscopic evidence of mast cell activation at such sites, taken together with the known functions of the diverse mediators, cytokines, and growth factors that can be secreted by appropriately activated mast cells, have suggested a wide range of possible functions for mast cells in promoting (or suppressing) many features of chronic inflammation. Similarly, these and other lines of evidence have implicated mast cells in a variety of adaptive or pathological responses that are associated with persistent inflammation at the affected sites. Definitively characterizing the importance of mast cells in chronic inflammation in humans is difficult. However, mice that genetically lack mast cells, especially those which can undergo engraftment with wildtype or genetically altered mast cells, provide a means to investigate the importance of mast cells and specific mast cell functions or products in diverse models of chronic inflammation. Such work has confirmed that mast cells can significantly influence multiple features of chronic inflammatory responses, through diverse effects that can either promote or, perhaps more surprisingly, suppress aspects of these responses.

Mast cells--key effector cells in immune responses

Mast cells are best known for their potent effector functions in allergic disorders. In recent years, however, mast cells have been identified to be involved in a surprisingly complex range of immune functions that go far beyond allergies and include the development of autoimmune disorders and peripheral tolerance, and the initiation and maintenance of adaptive and innate host responses. Here, we review the key signals and effector mechanisms that have lately been identified for mast cell functions in these immune responses.

Age and diet influence the composition of venom from the endoparasitic wasp Pimpla turionellae L. (Hymenoptera: Ichneumonidae)

Venom from the endoparasitic wasp Pimpla turionellae L. (Hymenoptera: Ichneumonidae) was found to contain a complex mixture of biogenic amines, noradrenalin, phospholipase B, and several proteins and peptides. The amount of noradrenalin and serotonin was found to be highest in venom from newly emerged wasps and decreased with age. Histamine was detected in minute amounts in comparison to the other venom components, and declined with increasing age of the parasitoids. Total peptides and proteins detected by reversed-phase HPLC increased with host age. Old-aged (30-33 days after emergence) wasps contained 2-fold more phospholipase B than young (<10 days [d] old) or medium-aged (10-22-d-old) females. Increases in phospholipase B alone, however, did not account for all changes in total venom protein because by 40 days after emergence, the levels of this enzyme began to decline while the amount of total protein was higher than in younger wasps. For all venom components detected, the amount present in the venom sharply decreased following host exposure. This was presumed to be the result of venom depletion associated with envenomation. Consistent with this view were the modest increases in venom components in wasps displaying a decreased rate of parasitization. When adult females were offered honey alone or in combination with feeding on hosts, no significant changes in venom composition were observed, with the exception of noradrenalin, which was found to be 5 times higher in concentration in wasps fed honey only. These results suggest that wasp age and incidence of parasitism are more important features influencing the composition of venom than the diet of adult females.