A pharmacological and biochemical examination of the geographical variation of Chironex fleckeri venom

Chironex fleckeri (box jellyfish) are found in the northern tropical waters of Australia. Although C. fleckeri have a wide geographical distribution and are able to swim large distances, adults tend to stay in small restricted areas. Clinical data shows that deaths from envenoming have not been recorded in Western Australia, yet numerous fatalities have occurred in Northern Territory and Queensland waters. One explanation for this discrepancy is a geographical variation in venom composition. This study examined the pharmacological and biochemical profiles of C. fleckeri venom from different geographical locations and seasons. Venoms were screened for cytotoxicity using a rat aortic smooth muscle cell line (A7r5). While all venoms caused concentration-dependent cytotoxicity, differences were seen in the potency of venoms from Mission Beach and Weipa, when collected in different seasons, as indicated by IC₅₀ values. Similarly venoms collected within the same season, from different locations around Australia, displayed marked differences in venom composition as shown by size exclusion HPLC and SDS-PAGE profiles which indicated the absence or reduced quantity of ‘peaks’ in some venoms. Based on IC₅₀ data obtained from the cell assay, the effects of the most potent (i.e. from Weipa in 2006) and the least potent (i.e. from Broome in 2007) venoms were examined in anesthetised rats. Both venoms at 10 μg/kg (i.v.) caused a transient hypertensive phase followed by cardiovascular collapse. However, at 4 μg/kg (i.v.) venom from Weipa 2006 caused a transient hypertensive phase followed by a transient decrease in MAP while venom from Broome 2007 only caused a small transient increase in MAP. This study demonstrates that there is considerable geographical variation in the composition of C. fleckeri venoms which is most distinct between specimens from western and eastern Australia and may explain the geographical variation in reported deaths.     

Clinical Marine Toxicology: A European Perspective for Clinical Toxicologists and Poison Centers

Clinical marine toxicology is a rapidly changing area. Many of the new discoveries reported every year in Europe involve ecological disturbances—including global warming—that have induced modifications in the chorology, behavior, and toxicity of many species of venomous or poisonous aquatic life including algae, ascidians, fish and shellfish. These changes have raised a number of public issues associated, e.g., poisoning after ingestion of contaminated seafood, envenomation by fish stings, and exposure to harmful microorganism blooms. The purpose of this review of medical and scientific literature in marine toxicology is to highlight the growing challenges induced by ecological disturbances that confront clinical toxicologists during the everyday job in the European Poison Centers.     

Stings of edible jellyfish (Rhopilema hispidum, Rhopilema esculentum and Nemopilema nomurai) in Japanese waters.

Three edible jellyfish Rhopilema hispidum, R. esculentum and Nemopilema nomurai are virulent to humans. We monitored one patient that was stung sequentially by these three species of jellyfish. The first species caused a persistent eruption, the second produced significant pruritus and the last induced only cutaneous symptoms rather than severe systemic disorders reported for its Chinese counterpart. The lesions of these jellyfish species are characteristic and common in workers harvesting medusae. There is no significant incidence of symptoms by ingesting these animals.     

Contact reactions to the jellyfish Carybdea marsupialis: observation of 40 cases

The clinical characteristics of 40 patients seen in an accident and emergency department after Contact with jellyfish while bathing in the sea are described.     

Experimental Assays to Assess the Efficacy of Vinegar and Other Topical First-Aid Approaches on Cubozoan (Alatina alata) Tentacle Firing and Venom Toxicity

Despite the medical urgency presented by cubozoan envenomations, ineffective and contradictory first-aid management recommendations persist. A critical barrier to progress has been the lack of readily available and reproducible envenomation assays that (1) recapitulate live-tentacle stings; (2) allow quantitation and imaging of cnidae discharge; (3) allow primary quantitation of venom toxicity; and (4) employ rigorous controls. We report the implementation of an integrated array of three experimental approaches designed to meet the above-stated criteria. Mechanistically overlapping, yet distinct, the three approaches comprised (1) direct application of test solutions on live tentacles (termed tentacle solution assay, or TSA) with single image- and video-microscopy; (2) spontaneous stinging assay using freshly excised tentacles overlaid on substrate of live human red blood cells suspended in agarose (tentacle blood agarose assays, or TBAA); and (3) a “skin” covered adaptation of TBAA (tentacle skin blood agarose assay, or TSBAA). We report the use and results of these assays to evaluate the efficacy of topical first-aid approaches to inhibit tentacle firing and venom activity. TSA results included the potent stimulation of massive cnidae discharge by alcohols but only moderate induction by urine, freshwater, and “cola” (carbonated soft drink). Although vinegar, the 40-year field standard of first aid for the removal of adherent tentacles, completely inhibited cnidae firing in TSA and TSBAA ex vivo models, the most striking inhibition of both tentacle firing and subsequent venom-induced hemolysis was observed using newly-developed proprietary formulations (Sting No More™) containing copper gluconate, magnesium sulfate, and urea.     

Jellyfish collagen matrices conserve the chondrogenic phenotype in two‐ and three‐dimensional collagen matrices

Cartilage is a tissue with a very low capability of self‐repair and the search for suitable materials supporting the chondrogenic phenotype and thus avoiding fibrotic dedifferentiation for matrix‐associated chondrocyte transplantation (MACI) is ongoing. Jellyfish collagen was thought to be a suitable material mainly because of its good availability and easy handling. Collagen was extracted from jellyfish Rhopilema esculentum and the spreading of porcine chondrocytes on two (2D) and three dimensional (3D) collagen matrices examined in comparison with vertebrate collagens, placenta collagen and a commercially available matrix from porcine collagen type I (Optimaix®). In 2D, most chondrocytes kept their round shape on jellyfish collagen and vertebrate collagen type II compared with vertebrate collagen type I. This was also confirmed in 3D experiments, where chondrocytes preserved their phenotype on jellyfish collagen, as indicated by high collagen II/(II + I) ratios (≥54 % and ~92 % collagen type II in mRNA and protein, respectively) and no proliferation during 28 days of cultivation. These observations were discussed with a view to potential structural differences of jellyfish collagen, which might influence the integrin‐mediated adhesion mechanisms of vertebrate cells on jellyfish collagen. This probably results from a lack of integrin‐binding sites and the existence of an alternative binding mechanism such that cells kept their round shape on jellyfish collagen, preventing chondrocytes from dedifferentiation. Thus, collagen from R. esculentum is a very suitable and promising material for cartilage tissue engineering. Copyright © 2015 John Wiley & Sons, Ltd.     

Benthic jellyfish dominate water mixing in mangrove ecosystems

Water mixing is a critical mechanism in marine habitats that governs many important processes, including nutrient transport. Physical mechanisms, such as winds or tides, are primarily responsible for mixing effects in shallow coastal systems, but the sheltered habitats adjacent to mangroves experience very low turbulence and vertical mixing. The significance of biogenic mixing in pelagic habitats has been investigated but remains unclear. In this study, we show that the upside-down jellyfish Cassiopea sp. plays a significant role with respect to biogenic contributions to water column mixing within its shallow natural habitat (<2 m deep). The mixing contribution was determined by high-resolution flow velocimetry methods in both the laboratory and the natural environment. We demonstrate that Cassiopea sp. continuously pump water from the benthos upward in a vertical jet with flow velocities on the scale of centimeters per second. The volumetric flow rate was calculated to be 212 L⋅h^-1 for average-sized animals (8.6 cm bell diameter), which translates to turnover of the entire water column every 15 min for a median population density (29 animals per m²). In addition, we found Cassiopea sp. are capable of releasing porewater into the water column at an average rate of 2.64 mL⋅h⁻¹ per individual. The release of nutrient-rich benthic porewater combined with strong contributions to water column mixing suggests a role for Cassiopea sp. as an ecosystem engineer in mangrove habitats.

Coastal mangrove habitats exhibit exceptionally high productivity and provide many ecosystem services, including control of flooding, sedimentation, and nutrient input in surrounding areas (1). In addition, these habitats act as critical nursery habitat for early life stages of a wide range of commercially and ecologically important species of fish and crustaceans (2, 3) and as adult habitat for many others (3). Mixing, which stirs gradients and homogenizes the water column, is a critical process which regulates important processes such as productivity (4) and benthic–pelagic coupling (5), prey encounter rate (6), and gas exchange (7). Thus, it is important to identify and understand the major sources of mixing within these coastal environments. Mixing forces are generally physical in origin, such as wind or tides, but, in some cases, they can originate from biotic sources. Biogenic mixing may be of particular importance in mangrove ecosystems, as these habitats experience comparatively little physical mixing due wind or tidal flow (8, 9).Previous studies have explored the role of biogenic mixing contributions of several taxa, including pelagic jellyfish, fish, and krill in the water column (10, 11), as well as benthic bivalves (12). These studies suggest the potential for nontrivial levels of animal-mediated mixing even in unsheltered environments, although others suggest a much lower level of mixing contribution (13) in the global oceans relative to processes such as internal waves. Little work is available regarding such effects in shallow (<2 m) habitats, however. One process by which internal waves might be produced is through interactions between tidal flow and topography in stratified waters, and these waves have been shown to interact with coastal ecosystems (14). However, in the much shallower, quiescent conditions of mangrove lagoons, these conditions do not appear to be present.While the turbulent mixing in shallow coastal ecosystems is often driven by wind and wave action (15), mangrove ecosystems provide shelter from wind and waves (9) and dampen mixing from high-velocity tidal currents, which tend to run, primarily, in deeper channels within mangrove ecosystems (16). Therefore, physical mixing is naturally low in Cassiopea sp. habitat, implying that animal-mediated mixing could have more substantial impacts in these environments.The upside-down jellyfish, Cassiopea sp., has a nearly circumtropical distribution (17). They are found in shallow, low-energy coastal environments, often dominated by the red mangrove, Rhizophora mangle (18), and have been previously documented at densities up to 31 animals per m² or 20% benthic coverage (19). In our field site, they were encountered at water depths of <2 m. Their natural range is extensive, and is further spreading due to their anthropogenic introduction as an invasive species (20–22) and through natural range expansion due to rising ocean temperatures (21). In addition, the size and abundance of Cassiopea sp. have increased near anthropogenically disturbed habitats, where nutrients tend to be elevated (23). These factors make Cassiopea sp. a potential indicator species for a variety of anthropogenic disturbances.Unlike most other jellyfish, Cassiopea sp. exhibit an epibenthic lifestyle, with their bell on the substrate and oral arms facing upward. They pulse their bells nearly continuously, producing a vertical jet (Fig. 1) (24–26); however, the extent of this vertical jet and volumetric flux have not been fully quantified. The direction of flow and volumetric fluxes may be particularly noteworthy given the fact that, in the absence of Cassiopea sp., there is a downward flux of nutrients, with the sediments acting as a nutrient sink in sheltered mangrove habitats (27). Thus, an upward pump at the benthos may serve to alter this flux and also interact with interstitial porewater, pulling a fraction of this water into the water column (26) and potentially affecting local productivity, as has been seen where benthic nutrients are released by bioturbation (28) or wind events (4).Open in a separate windowFig. 1.(A) Laboratory and (B) in situ PIV of a representative Cassiopea sp. jet. White arrows represent the velocity vectors, while colored areas represent the flow with either an upward (red) or downward (blue) component. (C) A cluster of animals produces multiple adjacent jets.In this study, we quantify the large-scale flow features of individual Cassiopea sp. as well as flows created by small groups both in the laboratory and in the field in order to test the hypothesis that range expansion and alterations in population densities of these benthic jellyfish could significantly increase mixing in otherwise quiescent habitat through the vertical excurrent jet of their feeding current. We discuss the results in the context of environmental mixing in mangrove ecosystems and examine the role of biological pumping at the surface of the benthos with respect to the liberation of interstitial porewater from the sediments.     

Cnidarians and human skin

Cnidarians are aquatic animals including the jellyfish, the Portuguese man-of-war, fire coral, hydroids, sea anemones, and coral. Many of these can harm human skin and rarely some envenomations can lead to a serious or even fatal outcome. This article discusses the varied creatures in this group that can harm man and potentially lead to serious envenomation syndromes. Treatment of cnidarian injuries and stings is discussed.     

凉拌海蛰制作过程中的细菌污染情况与分析

目的:了解凉拌海蛰制作过程中的细菌污染情况,并进行分析。方法:对凉拌海蛰加工的各个环节进行采样,如检测原料、调味料、加工用水、消毒容器、消毒后工作人员的手及环境中空气的细菌污染情况;同时凉拌海蛰分别腌制0、1、3、5、12 h后,进行细菌总数、大肠菌群数及潜在病原菌的测定。结果:凉拌海蛰在室温腌制过程中,均未检出大肠菌群和潜在病原菌;在室温腌制5 h内,随着腌制时间的延长,细菌总数有所减少,且符合国家标准;加工用水中自来水及冰水中的细菌总数分别高达3.5×104cfu/g、2.8×104cfu/g,不符合生活用水标准,对凉拌海蜇的污染较严重;原料中的细菌总数对凉拌海蜇的影响较大。结论:对凉拌海蛰制作的各个环节进行微生物污染控制,采取适当的消毒、防腐等措施,确保凉拌食品卫生安全。