Pharmacological and biochemical properties of a toxin containing material from the jellyfish, Cyanea capillata

A Review of Toxins from Cnidaria

Cnidarians have been known since ancient times for the painful stings they induce to humans. The effects of the stings range from skin irritation to cardiotoxicity and can result in death of human beings. The noxious effects of cnidarian venoms have stimulated the definition of their composition and their activity. Despite this interest, only a limited number of compounds extracted from cnidarian venoms have been identified and defined in detail. Venoms extracted from Anthozoa are likely the most studied, while venoms from Cubozoa attract research interests due to their lethal effects on humans. The investigation of cnidarian venoms has benefited in very recent times by the application of omics approaches. In this review, we propose an updated synopsis of the toxins identified in the venoms of the main classes of Cnidaria (Hydrozoa, Scyphozoa, Cubozoa, Staurozoa and Anthozoa). We have attempted to consider most of the available information, including a summary of the most recent results from omics and biotechnological studies, with the aim to define the state of the art in the field and provide a background for future research.

Biotechnological Applications of Scyphomedusae

As people across the world live longer, chronic illness and diminished well-being are becoming major global public health challenges. Marine biotechnology may help overcome some of these challenges by developing new products and know-how derived from marine organisms. While some products from marine organisms such as microalgae, sponges, and fish have already found biotechnological applications, jellyfish have received little attention as a potential source of bioactive compounds. Nevertheless, recent studies have highlighted that scyphomedusae (Cnidaria, Scyphozoa) synthesise at least three main categories of compounds that may find biotechnological applications: collagen, fatty acids and components of crude venom. We review what is known about these compounds in scyphomedusae and their current biotechnological applications, which falls mainly into four categories of products: nutraceuticals, cosmeceuticals, biomedicals, and biomaterials. By defining the state of the art of biotechnological applications in scyphomedusae, we intend to promote the use of these bioactive compounds to increase the health and well-being of future societies.

Intracellular Ca(2+) overload induced by extracellular Ca(2+) entry plays an important role in acute heart dysfunction by tentacle extract from the jellyfish Cyanea capillata

The exact mechanism of acute heart dysfunction caused by jellyfish venom remains unclear for the moment. In the present study, we examined the problem caused by the tentacle extract (TE) from the jellyfish Cyanea capillata at the levels of whole animal, isolated heart, primarily cultured cardiomyocytes, and intracellular Ca(2+). The heart indexes, including HR, APs, LVPs, and MMLs, were all decreased significantly by TE in both whole animal and Langendorff-perfused isolated heart model. Imbalance of cardiac oxygen supply and demand also took place. In both Ca(2+)-containing and Ca(2+)-free bathing solutions, TE could cause obvious cytoplasmic Ca(2+) overload in NRVMs, but the cytoplasmic Ca(2+) increased faster, Ca(2+) overload peaks arrived earlier, and the morphological changes were more severe under the extracellular Ca(2+)-containing condition. L-type Ca(2+) channel blockers, as well as the inhibitor of ryanodine receptor (ryanodine), could improve the viability of NRVMs. Moreover, diltiazem significantly inhibited the acute heart dysfunction caused by TE in both Langendorff isolated heart model and whole animal. These results suggested that intracellular Ca(2+) overload induced by extracellular Ca(2+) entry plays an important role in acute heart failure by TE from the jellyfish C. capillata. Inhibition of extracellular Ca(2+) influx is a promising antagonistic alternative for heart damage by jellyfish venom.

Comparison of haemolytic activity of tentacle-only extract from jellyfish Cyanea capillata in diluted whole blood and erythrocyte suspension: diluted whole blood is a valid test system for haemolysis study

In this paper, we utilized two different test systems to compare the haemolysis of tentacle-only extract (TOE) devoid of nematocysts from jellyfish Cyanea capillata, the 1% whole blood and 0.45% erythrocyte suspension approximately with the same erythrocyte concentration from the blood samples of sheep, rabbit, mouse, rat and human, respectively. Without exception, the haemolytic activity of TOE was dose-dependent in both test systems from all the five kinds of blood samples, while it was generally stronger in erythrocyte suspension than that in diluted whole blood at the relatively high concentration of TOE. When various aliquots of plasma were added into the erythrocyte suspension test system, the haemolytic activity of TOE was declined with the plasma quantity increasing, and dropped to about 20% at the presence of two aliquots of plasma. If serum albumin of 0.5 mg/ml, approximately the same albumin content in 1% whole blood, was added into the erythrocyte suspension test system instead, the haemolysis of TOE was similarly inhibited. The effects of GSH, ascorbic acid and protease inhibitor on the haemolytic activity of TOE were detected in the erythrocyte suspension and diluted whole blood simultaneously, and the test results were coincident between the two systems. These results suggested that the inconsistency of TOE haemolysis between the erythrocyte suspension and diluted whole blood is a universal occurrence in the mammals, and blood plasma plays a dose-dependent protective role against haemolysis which may be due to serum albumin. Diluted whole blood is a valid and convenient test system for haemolysis study in vitro.

A novel proteinaceous cytotoxin from the northern Scyphozoa Cyanea capillata (L.) with structural homology to cubozoan haemolysins

It is well known that jellyfish are producers of complex mixtures of proteinaceous toxins for prey capture and defence. Nevertheless, studies on boreal scyphozoans concerning venom composition and toxic effects are rare. Here the isolation of a novel cytotoxic protein from the fishing tentacle venom of Cyanea capillata (L. 1758) using bioactivity-guided, multidimensional liquid chromatography is described. The crude venom was purified utilising preparative size-exclusion, ion-exchange, and reversed-phase chromatography. The cytotoxicity of resulting chromatographic fractions has been proven by a dye-uptake assay with the human hepatocyte cell line HepG2. The final purification step yielded, among other fractions, a fraction containing a single protein (named CcTX-1) with a molecular weight of its main isoform of 31.17 kDa The purification process leads to an increased cytotoxic activity per protein equivalents and the finally isolated CcTX-1 caused a nearly total loss of cell viability at a protein concentration of 1.3 μg mL⁻¹ corresponding to 0.4 μg/10⁵ cells. De novo sequencing of CcTX-1 was conducted after enzymatic digestion and subsequent matrix-assisted laser desorption ionisation time-of-flight/time-of-flight mass spectrometry (MALDI-ToF/ToF MS/MS). The obtained sequence data provide an approximate 85% description of the amino acid sequence. This sequence information partially matched that of two known haemolytic proteins of two cubozoan species: CaTX-1 from Carybdea alata Reynaud, 1830 and CrTX-1 from Carybdea rastonii Haacke, 1886.

Herbal compounds and toxins modulating TRP channels

Although the benefits are sometimes obvious, traditional or herbal medicine is regarded with skepticism, because the mechanism through which plant compounds exert their powers are largely elusive. Recent studies have shown however that many of these plant compounds interact with specific ion channels and thereby modulate the sensing mechanism of the human body. Especially members of the Transient Receptor Potential (TRP) channels have drawn large attention lately as the receptors for plant-derived compounds such as capsaicin and menthol. TRP channels constitute a large and diverse family of channel proteins that can serve as versatile sensors that allow individual cells and entire organisms to detect changes in their environment. For this family, a striking number of empirical views have turned into mechanism-based actions of natural compounds. In this review we will give an overview of herbal compounds and toxins, which modulate TRP channels.

In vitro and in vivo haemolytic studies of tentacle-only extract from jellyfish Cyanea capillata

To approach the real haemolytic process of jellyfish toxins, both in vitro and in vivo haemolysis of tentacle-only extract (TOE) from jellyfish Cyanea capillata has been studied. Dose-response curves of the haemolytic activity of TOE in vitro were sigmoid shaped in both erythrocyte suspension and diluted whole blood, with the former more sensitive to TOE. The in vivo haemolysis increased sharply in the first 10 min and was followed by a gradual increase in the following 3h, with increasing blood potassium and lactic acid accordingly. SC5b-9 complexes were significantly up-regulated in vitro, but not in vivo. These results showed that the haemolysis of TOE in diluted whole blood and in vivo is not totally consistent with that in the erythrocyte suspension, and blood plasma might play a protective role against haemolysis. Thus we suggested that erythrocyte suspension can be used to test the damage of toxin on erythrocyte membrane, while the diluted whole blood may be more suitable to test the haemolysis of toxins.

In vivo effects of cnidarian toxins and venoms

Cnidarians (Coelenterates), a very old and diverse animal phylum, possess a wide variety of biologically active substances that can be considered as toxins. Anthozoan toxins can be classified into two chemically very different groups, namely polypeptide toxins isolated from sea anemones and diterpenes isolated from octocorals. Cubozoan and scyphozoan protein toxins have been the most elusive cnidarian toxins to investigate - despite a tremendous effort in the past few decades, very few of these large, relatively unstable protein toxins were isolated, but recently this has been achieved for cubozoan venoms. Hydrozoans mainly contain large proteins with physiological mechanisms of action similar to the sea anemone and jellyfish pore-forming toxins. This article will focus on the in vivo physiological effects of cnidarian toxins and venoms; their actions at the cellular level will only be considered to understand their actions at the organ and whole animal levels. An understanding of mechanisms underlying the in vivo toxic effects will facilitate the development of more effective treatments of cnidarian envenomations.

Comparative study on the cell toxicity and enzymatic activity of two northern scyphozoan species Cyanea capillata (L.) and Cyanea lamarckii (Péron & Léslieur)

Two species of venomous pelagic cnidaria are compared according to their enzymatic, cytotoxic and haemolytic potency. The widely distributed jellyfish Cyanea capillata and Cyanea lamarckii were collected in the North Sea at the coasts of the Orkney Island and the Island of Helgoland. Purified cnidocyst extracts from fishing and mesenteric tentacles were prepared and tested for their bioactivity. The haemolysis induced by toxins of C. capillata was determined with respect to organism size and toxigenic organs. The haemolytic activity of the related species C. lamarckii was documented for the first time. Dose dependent haemolytic activities have been detected by means of protein equivalents at concentrations above 20mug(protein)/mL. Extracts of fishing tentacle cnidocysts showed a less potent haemolytic activity compared to extracts of mesenteric tentacles. In vitro studies with permanent cells of a hepatoma cell line have shown a time and concentration dependent loss of cell vitality up to 90% at 33.3mug(protein)/mL (10mug(protein)/10(5) cells). Supplementing the cell based toxicity tests an enzyme assay was performed to measure a phospholipase A(2) (PLA(2)) activity. A PLA(2)-like activity could be demonstrated in cnidocysts extracts prepared from mesenteric and fishing tentacles of both jellyfish species.

Jellyfish and other cnidarian envenomations cause pain by affecting TRPV1 channels

Cnidarian envenomations cause a burning-pain sensation of which the underlying mechanisms are unknown. Activation of TRPV1, a non-selective cation channel expressed in nociceptive neurons, leads to cell depolarisation and pain. Here, we show in vitro and in vivo evidence for desensitization-dependent TRPV1 activation in cnidarian envenomations. Cnidarian venom induced a nociceptive reactivity, comparable to capsaicin, in laboratory rats, which could be reduced by the selective TRPV1 antagonist, BCTC. These findings are the first to explain at least part of the symptomology of cnidarian envenomations and provide insights into the design of more effective treatments for this global public health problem.

Australian venomous jellyfish, envenomation syndromes, toxins and therapy

The seas and oceans around Australia harbour numerous venomous jellyfish. Chironex fleckeri, the box jellyfish, is the most lethal causing rapid cardiorespiratory depression and although its venom has been characterised, its toxins remain to be identified. A moderately effective antivenom exists which is also partially effective against another chirodropid, Chiropsalmus sp. Numerous carybdeids, some unidentified, cause less severe illness, including Carybdea rastoni whose toxins CrTX-A and CrTX-B are large proteins. Carukia barnesi, another small carybdeid is one cause of the 'Irukandji' syndrome which includes delayed pain from severe muscle cramping, vomiting, anxiety, restlessness, sweating and prostration, and occasionally severe hypertension and acute cardiac failure. The syndrome is in part caused by release of catecholamines but the cause of heart failure is undefined. The venom contains a sodium channel modulator. Two species of Physalia are present and although one is potentially lethal, has not caused death in Australian waters. Other significant genera of jellyfish include Tamoya, Pelagia, Cyanea, Aurelia and Chyrosaora.

Biological properties of a venom extract from the sea anemone, Bunodosoma cavernata

Crude extract was prepared from the sea anemone, Bunodosoma cavernata. The protein content of the extract was estimated to be 0.52 mg protein/ml. The extract was standardized based on the percentage inhibition of histamine-induced contraction of the guinea pig ileum, to determine the biological unit of activity (AU) of the extract. As extracts prepared on different occasions lost potency on storage, the stability of the extract was also investigated. Extracts prepared from fresh animals were about 15% more potent than those prepared from freeze-dried animals. However, freeze-dried animal extracts maintained their potency for about 6 months under storage at -20 degrees C. Lethality studies gave an LD50 of 40 microg protein/kg mice i.p. Also, the crude extract dose-dependently hemolyzed human erythrocytes at room temperature. This activity was favoured by higher temperatures, which peaked at about 60degrees C, and by pH in the alkaline range. We conclude that the crude extract from B. cavernata, though highly toxic, may also contain some biologically active agents which include a haemolytic factor and antihistamine(s), as indicated by its histamine-blocking action.

Venomous pelagic coelenterates: chemistry, toxicology, immunology and treatment of their stings

Ten years have elapsed since our last review article on the toxicology of venomous pelagic coelenterates was published (Burnett and Calton, 1977). Investigation on important medusae and the chemistry of their nematocyst venoms have been expanding. The venomous jellyfish discussed here include the Portuguese man-o'war, (Physalia physalis), the sea nettle (Chrysaora quinquecirrha), the box jellyfish (Chironex fleckeri and/or Chiropsalmus quadrigatus), the cabbage head jellyfish (Stomolophus meleagris), the lion's mane jellyfish (Cyanea capillata), the Irukandji jellyfish (Carukia barnesi), the Moreton Bay Carybdeid medusa (Morbakka), and the mauve blubber (Pelagia noctiluca).

Sea nettle (Chrysaora quinquecirrha) nematocyst venom: mechanism of action on muscle

The cellular mechanism of toxicity of sea nettle nematocyst venom was studied in the isolated, perfused frog ventricle and the isolated frog sartorius muscle. The venom depolarized both cardiac muscle fibers and sartorius fibers and shortened the duration of the ventricular action potential. Sodium content was increased, potassium content was decreased and magnesium content was unaltered in both tissues upon exposure to venom. Calcium content increased in heart ventricle, twitch tension decreased and a contracture developed. The calcium content of venom-treated, quiescent sartorius muscles was not changed from control. In stimulated sartorius muscles, tetanus tension fell during venom treatment, the twitch response was variable and no contracture was seen. Venom-treated sartorius muscles incubated with 5 mM Rb+, Cs+ or Li+ took up twice the amount of each cation as did control muscles. Sea nettle venom decreased the resistance of black lipid membranes in discrete steps, each step corresponding to a transfer of about 2 X 10(7) ions/sec at a potential of 20 mV in Ringer's solution. It was concluded that a component of sea nettle venom forms a monovalent cation channel in cardiac skeletal muscle surface membranes that allows a rapid influx of sodium into the cell.