Evaluation of the effects of various chemicals on discharge of and pain caused by jellyfish nematocysts

Jellyfish tentacles in contact with human skin can produce pain swelling and redness. The pain is due to discharge of jellyfish nematocysts and associated toxins and discharge can be caused by a variety of mechanical and chemical stimuli. A series of tests were carried out with chemicals traditionally used to treat jellyfish stings e.g. acetic acid ammonia meat tenderizer baking soda and urea to determine if these chemicals stimulated or inhibited nematocyst discharge and if they brought relief to testers who were exposed to jellyfish tentacles. Chrysaora quinquecirrha (sea nettle) Chiropsalmus quadrumanus (sea wasp) and Physalia physalis (Portuguese man-of-war) were used in the study. It was found that many of the chemicals traditionally used to treat jellyfish stings stimulated nematocyst discharge and did not relieve the pain. However there was immediate relief when a common anesthetic lidocaine was sprayed on the skin of testers in contact with jellyfish tentacles. Initial exposure of tentacle suspensions to lidocaine prevented the nematocyst discharge by subsequent exposure to acetic acid ethanol ammonia or bromelain. Thus lidocaine in addition to acting as an anesthetic on skin in contact with jellyfish tentacles inhibited nematocyst discharge possibly by blocking sodium and/or calcium channels of the nematocytes.     

沙蜇(Stomolophus meleagris)刺丝囊毒素生物活性的初步分析

从沙蜇触手提取刺丝囊细胞毒素,并对该毒素进行溶血活性、致死活性、SOD活性和抗肿瘤活性的研究。结果显示,沙蜇毒素具有明显的溶血活性,其半溶血率(HU50)约为10.5μg/ml;该毒素还对草鱼显示出较强的致死活性,半致死量(LD50)为50μg毒素/g鱼;同时该毒素具有明显的SOD活性和抗肿瘤活性,当毒素浓度为18μg/ml时其总SOD活性为161 U/mg,而毒素浓度为1 mg/ml时,该毒素对肝癌细胞Bel-7402表现出显著的抑制效果,其抑制率达到54.9%。因此,有必要对沙蜇毒素内的生物活性组分进行深入研究,为沙蜇毒素的开发利用提供依据。     

Protective Effect of Tetracycline against Dermal Toxicity Induced by Jellyfish Venom

Background

Previously, we have reported that most, if not all, of the Scyphozoan jellyfish venoms contain multiple components of metalloproteinases, which apparently linked to the venom toxicity. Further, it is also well known that there is a positive correlation between the inflammatory reaction of dermal tissues and their tissue metalloproteinase activity. Based on these, the use of metalloproteinase inhibitors appears to be a promising therapeutic alternative for the treatment of jellyfish envenomation.

Methodology and Principal Findings

Tetracycline (a metalloproteinase inhibitor) has been examined for its activity to reduce or prevent the dermal toxicity induced by Nemopilema nomurai (Scyphozoa: Rhizostomeae) jellyfish venom (NnV) using in vitro and in vivo models. HaCaT (human keratinocyte) and NIH3T3 (mouse fibroblast) incubated with NnV showed decreases in cell viability, which is associated with the inductions of metalloproteinase-2 and -9. This result suggests that the use of metalloproteinase inhibitors, such as tetracycline, may prevent the jellyfish venom-mediated local tissue damage. In vivo experiments showed that comparing with NnV-alone treatment, tetracycline pre-mixed NnV demonstrated a significantly reduced progression of dermal toxicity upon the inoculation onto rabbit skin.

Conclusions/Significance

It is believed that there has been no previous report on the therapeutic agent of synthetic chemical origin for the treatment of jellyfish venom-induced dermonecrosis based on understanding its mechanism of action except the use of antivenom treatment. Furthermore, the current study, for the first time, has proposed a novel mechanism-based therapeutic intervention for skin damages caused by jellyfish stings.     

Cubozoan Venom-Induced Cardiovascular Collapse Is Caused by Hyperkalemia and Prevented by Zinc Gluconate in Mice

Chironex fleckeri (Australian box jellyfish) stings can cause acute cardiovascular collapse and death. We developed methods to recover venom with high specific activity, and evaluated the effects of both total venom and constituent porins at doses equivalent to lethal envenomation. Marked potassium release occurred within 5 min and hemolysis within 20 min in human red blood cells (RBC) exposed to venom or purified venom porin. Electron microscopy revealed abundant ∼12-nm transmembrane pores in RBC exposed to purified venom porins. C57BL/6 mice injected with venom showed rapid decline in ejection fraction with progression to electromechanical dissociation and electrocardiographic findings consistent with acute hyperkalemia. Recognizing that porin assembly can be inhibited by zinc, we found that zinc gluconate inhibited potassium efflux from RBC exposed to total venom or purified porin, and prolonged survival time in mice following venom injection. These findings suggest that hyperkalemia is the critical event following Chironex fleckeri envenomation and that rapid administration of zinc could be life saving in human sting victims.     

The making of a pest: the evolution of a fruit-penetrating ovipositor in Drosophila suzukii and related species

Evolutionary innovation can allow a species access to a new ecological niche, potentially reducing competition with closely related species. While the vast majority of Drosophila flies feed on rotting fruit and other decaying matter, and are harmless to human activity, Drosophila suzukii, which has a morphologically modified ovipositor, is capable of colonizing live fruit that is still in the process of ripening, causing massive agricultural damage. Here, we conducted the first comparative analysis of this species and its close relatives, analysing both ovipositor structure and fruit susceptibility. We found that the ovipositor of the species most closely related to D. suzukii, Drosophila subpulchrella, has a similar number of enlarged, evolutionarily derived bristles, but a notably different overall shape. Like D. suzukii, D. subpulchrella flies are capable of puncturing the skin of raspberries and cherries, but we found no evidence that they could penetrate the thicker skin of two varieties of grapes. More distantly related species, one of which has previously been mistaken for D. suzukii, have blunt ovipositors with small bristles. While they did not penetrate fruit skin in any of the assays, they readily colonized fruit interiors where the skin was broken. Our results suggest that considering evolutionary context may be beneficial to the management of invasive species.     

Chironex fleckeri (Box Jellyfish) Venom Proteins: EXPANSION OF A CNIDARIAN TOXIN FAMILY THAT ELICITS VARIABLE CYTOLYTIC AND CARDIOVASCULAR EFFECTS*

The box jellyfish Chironex fleckeri produces extremely potent and rapid-acting venom that is harmful to humans and lethal to prey. Here, we describe the characterization of two C. fleckeri venom proteins, CfTX-A (∼40 kDa) and CfTX-B (∼42 kDa), which were isolated from C. fleckeri venom using size exclusion chromatography and cation exchange chromatography. Full-length cDNA sequences encoding CfTX-A and -B and a third putative toxin, CfTX-Bt, were subsequently retrieved from a C. fleckeri tentacle cDNA library. Bioinformatic analyses revealed that the new toxins belong to a small family of potent cnidarian pore-forming toxins that includes two other C. fleckeri toxins, CfTX-1 and CfTX-2. Phylogenetic inferences from amino acid sequences of the toxin family grouped CfTX-A, -B, and -Bt in a separate clade from CfTX-1 and -2, suggesting that the C. fleckeri toxins have diversified structurally and functionally during evolution. Comparative bioactivity assays revealed that CfTX-1/2 (25 μg kg⁻¹) caused profound effects on the cardiovascular system of anesthetized rats, whereas CfTX-A/B elicited only minor effects at the same dose. Conversely, the hemolytic activity of CfTX-A/B (HU₅₀ = 5 ng ml⁻¹) was at least 30 times greater than that of CfTX-1/2. Structural homology between the cubozoan toxins and insecticidal three-domain Cry toxins (δ-endotoxins) suggests that the toxins have a similar pore-forming mechanism of action involving α-helices of the N-terminal domain, whereas structural diversification among toxin members may modulate target specificity. Expansion of the cnidarian toxin family therefore provides new insights into the evolutionary diversification of box jellyfish toxins from a structural and functional perspective.     

Toxinological and immunological studies of capillary electrophoresis fractionated Chrysaora quinquecirrha (Desor) fishing tentacle and Chironex fleckeri Southcott nematocyst venoms

Repeated runs of capillary electrophoresis (CE) were used to study partially-purified jellyfish nematocyst venom protein in concentrations sufficient to perform toxinological assays. Nematocyst venoms from Chironex fleckeri (Cf) and Chysaora quinquecirrha were processed. The CE eluate was divided into quadrants by scanning protein content. The fourth fraction of both jellyfish venoms, contained proteins with the smallest molecular weight components, which were responsible for the highest hemolysins and the humoral and cell-mediated immunological activity. Cytotoxic Cf lethal factor activity against human liver cells was widely dispersed throughout both venoms but more prominent in fraction 4. A V(beta) receptor human T-cell repertoire was not species-specific for either crude or fractionated jellyfish nematocyst venom.     

Jellyfish as Prey: Frequency of Predation and Selective Foraging of Boops boops (Vertebrata,Actinopterygii) on the Mauve Stinger Pelagia noctiluca (Cnidaria,Scyphozoa)

In recent years, jellyfish blooms have attracted considerable scientific interest for their potential impacts on human activities and ecosystem functioning, with much attention paid to jellyfish as predators and to gelatinous biomass as a carbon sink. Other than qualitative data and observations, few studies have quantified direct predation of fish on jellyfish to clarify whether they may represent a seasonally abundant food source. Here we estimate predation frequency by the commercially valuable Mediterranean bogue, Boops boops on the mauve stinger jellyfish, Pelagia noctiluca, in the Strait of Messina (NE Sicily). A total of 1054 jellyfish were sampled throughout one year to quantify predation by B. boops from bite marks on partially eaten jellyfish and energy density of the jellyfish. Predation by B. boops in summer was almost twice that in winter, and they selectively fed according to medusa gender and body part. Calorimetric analysis and biochemical composition showed that female jellyfish gonads had significantly higher energy content than male gonads due to more lipids and that gonads had six-fold higher energy content than the somatic tissues due to higher lipid and protein concentrations. Energetically, jellyfish gonads represent a highly rewarding food source, largely available to B. boops throughout spring and summer. During the remainder of the year, when gonads were not very evident, fish predation switched towards less-selective foraging on the somatic gelatinous biomass. P. noctiluca, the most abundant jellyfish species in the Mediterranean Sea and a key planktonic predator, may represent not only a nuisance for human leisure activities and a source of mortality for fish eggs and larvae, but also an important resource for fish species of commercial value, such as B. boops.     

Deterministic Factors Overwhelm Stochastic Environmental Fluctuations as Drivers of Jellyfish Outbreaks

Jellyfish outbreaks are increasingly viewed as a deterministic response to escalating levels of environmental degradation and climate extremes. However, a comprehensive understanding of the influence of deterministic drivers and stochastic environmental variations favouring population renewal processes has remained elusive. This study quantifies the deterministic and stochastic components of environmental change that lead to outbreaks of the jellyfish Pelagia noctiluca in the Mediterranen Sea. Using data of jellyfish abundance collected at 241 sites along the Catalan coast from 2007 to 2010 we: (1) tested hypotheses about the influence of time-varying and spatial predictors of jellyfish outbreaks; (2) evaluated the relative importance of stochastic vs. deterministic forcing of outbreaks through the environmental bootstrap method; and (3) quantified return times of extreme events. Outbreaks were common in May and June and less likely in other summer months, which resulted in a negative relationship between outbreaks and SST. Cross- and along-shore advection by geostrophic flow were important concentrating forces of jellyfish, but most outbreaks occurred in the proximity of two canyons in the northern part of the study area. This result supported the recent hypothesis that canyons can funnel P. noctiluca blooms towards shore during upwelling. This can be a general, yet unappreciated mechanism leading to outbreaks of holoplanktonic jellyfish species. The environmental bootstrap indicated that stochastic environmental fluctuations have negligible effects on return times of outbreaks. Our analysis emphasized the importance of deterministic processes leading to jellyfish outbreaks compared to the stochastic component of environmental variation. A better understanding of how environmental drivers affect demographic and population processes in jellyfish species will increase the ability to anticipate jellyfish outbreaks in the future.     

Minicollagen-15, a novel minicollagen isolated from Hydra, forms tubule structures in nematocysts

Minicollagens constitute a family of unusually short collagen molecules isolated from cnidarians. They are restricted to the nematocyst, a cylindrical explosive organelle serving in defense and capture of prey. The nematocyst capsule contains a long tubule inside of its matrix, which is expelled and everted during an ultrafast discharge process. Here, we report the cloning and characterization of a novel minicollagen in Hydra, designated minicollagen-15 (NCol-15). NCol-15, like NCol-3 and NCol-4, shows deviations from the canonical cysteine pattern in its terminal cysteine-rich domains (CRDs). Minicollagens share common domain architectures with a central collagen sequence flanked by polyproline stretches and short N- and C-terminal CRDs. The CRDs are involved in the formation of a highly resistant cysteine network, which constitutes the basic structure of the nematocyst capsule. Unlike NCol-1, which is part of the capsule wall, NCol-15 is localized to tubules, arguing for a functional differentiation of minicollagens within the nematocyst architecture. NMR analysis of the altered C-terminal CRD of NCol-15 showed a novel disulfide-linked structure within the cysteine-containing region exhibiting similar folding kinetics and stability as the canonical CRDs. Our data provide evidence for evolutionary diversification among minicollagens, which probably facilitated alterations in the morphology of the nematocyst wall and tubule.     

Predation by the phyllosoma larva of Ibacus novemdentatus on various kinds of venomous jellyfish

The phyllosoma, a larva of spiny and slipper lobsters, has an exceptionally flat body and long appendages. It is known to associate with several species of cnidarian jellyfish, a behavior that is not rare in crustaceans. Indeed, phyllosomas clinging onto jellyfish have been observed both in the laboratory and in the natural environment. Wild phyllosomas have been found to contain jellyfish tissues in their hepatopancreas and feces, suggesting that the larvae utilize jellyfish as a food source; however, how they capture jellyfish and what species of jellyfish they prefer have rarely been investigated. The few previous studies conducted have suggested that phyllosomas have a high specificity for jellyfish (preying on only a few species); in contrast, the results of our study indicate that specificity is low. We show that phyllosomas prey on a variety of jellyfish species including deadly stinging types, on a variety of jellyfish developmental stages, and on various parts of the jellyfish body. When making contact with a jellyfish, phyllosomas first cling onto its exumbrella, feed on its tentacles or oral arms, and then consume the exumbrella. Phyllosomas may be capable of defending themselves against any types of nematocyst sting, and it is likely that they have evolved to utilize venomous jellyfish as a food in the open sea, where food may be scarce.     

Isolation,characterization, and comparison of hemolytic peptides in nematocyst venoms of two species of jellyfish (Chrysaora quinquecirrha and Cyanea capillata)

• 1.1. Hemolysins of the sea nettle, Chrysaora quinquecirrha, and the lions' mane jellyfish, Cyanea capillata, collected in the Delaware Bay were partially purified by sequential gel-filtration and high performance liquid chromatography.
• 2.2. The nematocyst contents of both jellyfish had hemolytically active fractions containing large quantities of glycine and serine along with an unknown amino acid residue.
• 3.3. The Chrysaora hemolysin appeared to have a mol. wt greater than 6000 but less than 10,000 daltons.
• 4.4. Glycophorins were the most effective inhibitors to the hemolysins at the lowest concentration.

     

Separation and analysis of different types of nematocysts from <Emphasis Type="Italic">Cyanea capillata</Emphasis> (L.) medusae

Medusae play an important role in marine ecosystems, as competitors of many invertebrate and fish species. Additionally, jellyfish stings can cause severe pain, inflammation of the affected skin, and allergic reactions in human. Climate and environmental changes are likely to affect the medusae, but it is not yet clear whether these will affect their distribution, physiology, and their toxicity. Very little is known about the effect of biotic and abiotic factors on the proliferation and the distribution of medusan nematocysts. In this study, we compared three types of nematocysts (euryteles and A- and O-isorhizas) and venoms of Cyanea capillata medusae (Scyphozoa) obtained from the North Sea and the Baltic Sea, which have different salinity and temperature ranges. Different types of nematocysts were separated by laser microdissection and pressure catapulting (LMPC), and the proteinaceous contents of the nematocysts were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Medusae from the brackish Baltic Sea possessed more euryteles than those from the North Sea. The O-isorhizas and A-isorhizas were smaller in the Baltic Sea sample compared to the North Sea samples and the length-to-width ratios were larger in the Baltic Sea sample. Moreover, the pattern of proteins (potential toxins) obtained from the separated nematocysts showed differences among samples and nematocyst types, but no clear pattern was observable. This study displays the novel LMPC/MALDI-TOF MS approach as a useful tool to investigate the function and venom of cnidarian nematocysts types.     

Exceptions to the prevailing pattern of tubules (9 + 9 + 2) in the sperm flagella of certain insect species

Various deviations from classical 9 + 2 flagellar structure are found in sperm of insect species. In mature spermatozoa of a psocid, Psocus, the outer flagellar tubules are not straight, but are disposed in a long-pitched helix such that they form an angle of about 8° with a single dense rod located in the position usually occupied by the central pair. In young spermatids of Psocus the outer tubules are straight; thus, spiraling of the flagellar tubules occurs during the course of spermiogenesis. Spiraling of flagella also occurs in the cat flea Ctenocephalides felis. Variations in the number and morphology of the central element or elements occur in other insect species besides Psocus. Among the observed deviations from a central pair of tubules are a 9 + 0 tubule pattern in the sperm of three species of mayflies, a 9 + 1 tubule pattern in the sperm of two species of mosquitoes, and 9 + 7 tubules in sperm of two species of caddis flies. Spermatozoa of treehoppers vary in yet another respect from the typical 9 + 9 + 2 insect flagellum. These sperm tails branch into four long tails, three of which each contain two doublet and two singlet tubules while the fourth branch contains three doublet and three singlet tubules. The wide distribution of insects with aberrant flagella suggests that the variant forms have evolved independently.     

Expression profiling and cellular localization of myxozoan minicollagens during nematocyst formation and sporogenesis

In free-living cnidarians, minicollagens are major structural components in the biogenesis of nematocysts. Recent sequence mining and proteomic analysis demonstrate that minicollagens are also expressed by myxozoans, a group of evolutionarily ancient cnidarian endoparasites. Nonetheless, the presence and abundance of nematocyst-associated genes/proteins in nematocyst morphogenesis have never been studied in Myxozoa. Here, we report the gene expression profiles of three myxozoan minicollagens, ncol-1, ncol-3, and the recently identified noncanonical ncol-5, during the intrapiscine development of Myxidium lieberkuehni, the myxozoan parasite of the northern pike, Esox lucius. Moreover, we localized the myxozoan-specific minicollagen Ncol-5 in the developing myxosporean stages by Western blotting, immunofluorescence, and immunogold electron microscopy. We found that expression of minicollagens was spatiotemporally restricted to developing nematocysts within the myxospores during sporogenesis. Intriguingly, Ncol-5 is localized in the walls of nematocysts and predominantly in nematocyst tubules. Overall, we demonstrate that despite being significantly reduced in morphology, myxozoans retain structural components associated with nematocyst development in free-living cnidarians. Furthermore, our findings have practical implications for future functional and comparative studies as minicollagens are useful markers of the developmental phase of myxozoan parasites.     

THE AXOSTYLE OF SACCINOBACULUS : I. Structure of the Organism and Its Microtubule Bundle

The axostyle of the flagellate Saccinobaculus is a motile ribbon composed of microtubules, cross-bridged to form interconnected rows. We find a centriole-related row of dark-staining tubules near the nucleus at the anterior end of the axostyle. Other tubule rows bind parallel to this primary row, acquire ordered relationships, and become the tubules of the axostyle proper. The number of tubule rows is constant in Saccinobaculus lata from the region near the nucleus to within a few micrometers of the posterior tip of the cell. In Saccinobaculus ambloaxostylus a few tubule rows are added to the axostyle posterior to the nucleus, giving this axostyle a leaf spring construction. The tubules of S. lata are held in rows by links with a 140 Å periodicity along the tubule axis; bridges between rows of tubules are also seen but are not apparently periodic. Each tubule in S. ambloaxostylus shows an axial periodicity of 150 Å due to pairs of arms, one of which is always part of the intrarow link. Interrow bridges in this species run either from tubule to tubule or from tubule to the free arm, but as in S. lata they do not display an obvious axial periodicity. An average unit cell is presented for the axostyle of each species, and the relation of the intertubule links to the microtubule substructure is discussed.