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Kasheverov IE, Logashina YA, Kornilov FD, Lushpa VA, Maleeva EE, Korolkova YV, Yu J, Zhu X, Zhangsun D, Luo S, Stensvåg K, Kudryavtsev DS, Mineev KS, Andreev YA. Peptides from the Sea Anemone Metridium senile with Modified Inhibitor Cystine Knot (ICK) Fold Inhibit Nicotinic Acetylcholine Receptors. Toxins (Basel) 2022; 15:28. [PMID: 36668848 PMCID: PMC9866706 DOI: 10.3390/toxins15010028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/21/2022] [Accepted: 12/26/2022] [Indexed: 01/03/2023] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) play an important role in the functioning of the central and peripheral nervous systems, and other organs of living creatures. There are several subtypes of nAChRs, and almost all of them are considered as pharmacological targets in different pathological states. The crude venom of the sea anemone Metridium senile showed the ability to interact with nAChRs. Four novel peptides (Ms11a-1-Ms11a-4) with nAChR binding activity were isolated. These peptides stabilized by three disulfide bridges have no noticeable homology with any known peptides. Ms11a-1-Ms11a-4 showed different binding activity towards the muscle-type nAChR from the Torpedo californica ray. The study of functional activity and selectivity for the most potent peptide (Ms11a-3) revealed the highest antagonism towards the heterologous rat α9α10 nAChR compared to the muscle and α7 receptors. Structural NMR analysis of two toxins (Ms11a-2 and Ms11a-3) showed that they belong to a new variant of the inhibitor cystine knot (ICK) fold but have a prolonged loop between the fifth and sixth cysteine residues. Peptides Ms11a-1-Ms11a-4 could represent new pharmacological tools since they have structures different from other known nAChRs inhibitors.
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Affiliation(s)
- Igor E. Kasheverov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, str. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Yulia A. Logashina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, str. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Trubetskaya str. 8, bld. 2, 119991 Moscow, Russia
| | - Fedor D. Kornilov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, str. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Moscow Institute of Physics and Technology, Institutsky per., 9, 141700 Dolgoprudnyi, Russia
| | - Vladislav A. Lushpa
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, str. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Moscow Institute of Physics and Technology, Institutsky per., 9, 141700 Dolgoprudnyi, Russia
| | - Ekaterina E. Maleeva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, str. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Yuliya V. Korolkova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, str. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Jinpeng Yu
- Medical School, Guangxi University, Nanning 530004, China
| | - Xiaopeng Zhu
- Medical School, Guangxi University, Nanning 530004, China
| | | | - Sulan Luo
- Medical School, Guangxi University, Nanning 530004, China
| | - Klara Stensvåg
- Faculty of Biosciences, Fisheries and Economics, Norwegian College of Fishery Science, UiT—The Arctic University of Norway, NO 9037 Tromsø, Norway
| | - Denis S. Kudryavtsev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, str. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Konstantin S. Mineev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, str. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Moscow Institute of Physics and Technology, Institutsky per., 9, 141700 Dolgoprudnyi, Russia
| | - Yaroslav A. Andreev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, str. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Trubetskaya str. 8, bld. 2, 119991 Moscow, Russia
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Anthony S. Cnida sequestration in aeolid nudibranchs: variability and retention time of sequestered cnidae in the opalescent sea slug, Hermissenda crassicornis (Gastropoda, Nudibranchia). CAN J ZOOL 2020. [DOI: 10.1139/cjz-2020-0010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aeolid sea slugs can isolate and store stinging cnidae obtained from their cnidarian prey, presumably for their own defence. There are 30 different varieties of cnidae, identified by their unique structure. The aeolids engulf the cnidae and store them in a functional state at the tips of their cerata. Although the process of cnida sequestration is reasonably well understood in aeolids, two critical questions remain: (1) are cnida types uniformly distributed among the cerata and (2) how long do sequestered cnidae persist? I collected opalescent sea slugs (Hermissenda crassicornis (Eschscholtz, 1831)) from Barkley Sound, British Columbia, Canada, and determined the cnida complements in four cerata per individual by microscope. The cnida complements differed between cerata from different body regions within the individual (values of Whittaker’s dissimilarity index from 2.5% to 36.3%). Furthermore, the cnidae varieties in low abundances are not consistently present within an individual. I also found that H. crassicornis fed a non-cnidarian diet lost cnidae over time, but the cnidarian-fed individuals did not: 3 of 10 H. crassicornis on the non-cnidarian diet lacked cnidae completely at 42 days. Future studies of cnida sequestration should be mindful that one ceras does not give an adequate representation of the distribution of sequestered cnidae.
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Affiliation(s)
- S.E. Anthony
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada; Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada
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O'Hanlon A, Williams CD, Gormally MJ. Terrestrial slugs (Mollusca: Gastropoda) share common anti‐predator defence mechanisms but their expression differs among species. J Zool (1987) 2018. [DOI: 10.1111/jzo.12635] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- A. O'Hanlon
- Applied Ecology Unit School of Natural Sciences National University of Ireland Galway Ireland
- Ryan Institute National University of Ireland Galway Ireland
| | - C. D. Williams
- School of Natural Sciences and Psychology Faculty of Science Liverpool John Moores University Liverpool UK
| | - M. J. Gormally
- Applied Ecology Unit School of Natural Sciences National University of Ireland Galway Ireland
- Ryan Institute National University of Ireland Galway Ireland
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Sun Z, Hamel JF, Parrish CC, Mercier A. Complex offspring size effects: variations across life stages and between species. Ecol Evol 2015; 5:1117-29. [PMID: 25798228 PMCID: PMC4364825 DOI: 10.1002/ece3.1320] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 11/04/2014] [Indexed: 11/09/2022] Open
Abstract
Classical optimality models of offspring size and number assume a monotonically increasing relationship between offspring size and performance. In aquatic organisms with complex life cycles, the size-performance function is particularly hard to grasp because measures of performance are varied and their relationships with size may not be consistent throughout early ontogeny. Here, we examine size effects in premetamorphic (larval) and postmetamorphic (juvenile) stages of brooding marine animals and show that they vary contextually in strength and direction during ontogeny and among species. Larger offspring of the sea anemone Urticina felina generally outperformed small siblings at the larval stage (i.e., greater settlement and survival rates under suboptimal conditions). However, results differed when analyses were conducted at the intrabrood versus across-brood levels, suggesting that the relationship between larval size and performance is mediated by parentage. At the juvenile stage (15 months), small offspring were less susceptible than large ones to predation by subadult nudibranchs and both sizes performed similarly when facing adult nudibranchs. In a sympatric species with a different life history (Aulactinia stella), all juveniles suffered similar predation rates by subadult nudibranchs, but smaller juveniles performed better (lower mortalities) when facing adult nudibranchs. Size differences in premetamorphic performance of U. felina were linked to total lipid contents of larvae, whereas size-specific predation of juvenile stages followed the general predictions of the optimal foraging strategy. These findings emphasize the challenge in gathering empirical support for a positive monotonic size-performance function in taxa that exhibit complex life cycles, which are dominant in the sea.
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Affiliation(s)
- Zhao Sun
- Department of Ocean Sciences, Memorial University St. John's, Newfoundland and Labrador, A1C 5S7, Canada
| | - Jean-François Hamel
- Society for the Exploration and Valuing of the Environment (SEVE) 21 Phils Hill Road, Portugal Cove-St. Philips, Newfoundland and Labrador, A1M 2B7, Canada
| | - Christopher C Parrish
- Department of Ocean Sciences, Memorial University St. John's, Newfoundland and Labrador, A1C 5S7, Canada
| | - Annie Mercier
- Department of Ocean Sciences, Memorial University St. John's, Newfoundland and Labrador, A1C 5S7, Canada
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Coyne K, Laursen JR, Yoshino TP. In Vitro Effects of Mucus from the Mantle of Compatible (Lymnaea elodes) and Incompatible (Helisoma trivolvis) Snail Hosts on Fascioloides magna Miracidia. J Parasitol 2015; 101:351-7. [PMID: 25602486 DOI: 10.1645/14-606.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The epidermal mucus covering the surface of a snail represents an important barrier to trematode larvae attempting to penetrate the snail and may play a role in mediating snail-trematode compatibility. In this study, Facioloides magna miracidia were exposed to mucus harvested from a compatible snail host, Lymnaea elodes (palustris), and from an incompatible snail, Helisoma trivolvis . In vitro treatment of freshly hatched miracidia with snail-derived mucus exerted dramatically different effects on larvae depending on snail species. At the lowest dilution of mucus tested (1:3) mean damage rates (tegumental damage and/or larval lysis and death) were as high as 100% for miracidia exposed to H. trivolvis mucus, while none of F. magna miracidia were damaged in L. elodes mucus. A dilution series for each snail species, and treatments with heat and proteinase K were performed to characterize the component(s) of mucus inducing the observed morphological changes. The damaging effects of H. trivolvis mucus were concentration dependent and completely abrogated by heat (65 C, 30 min) and proteinase treatment, strongly implicating a heat-labile protein(s) in mucus as the active cytotoxic agent(s). In contrast to our prediction that miracidial contact with mucus of compatible L. elodes would trigger larval transformation, mucus from either snail species tested exhibited little to no activity. Overall these data demonstrate the presence of a potent cytotoxic protein-like factor in the mucus of F. magna -incompatible H. trivolvis , and its absence in the mucus of the compatible snail, L. elodes . This finding supports the notion that the epidermal mucus layer may be serving as an important determinant of larval trematode-snail compatibility.
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Affiliation(s)
- Kathyrn Coyne
- Department of Pathobiological Sciences, University of Wisconsin, School of Veterinary Medicine, Madison, Wisconsin 53706
| | - Jeffrey R Laursen
- Department of Pathobiological Sciences, University of Wisconsin, School of Veterinary Medicine, Madison, Wisconsin 53706
| | - Timothy P Yoshino
- Department of Pathobiological Sciences, University of Wisconsin, School of Veterinary Medicine, Madison, Wisconsin 53706
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Savitzky AH, Mori A, Hutchinson DA, Saporito RA, Burghardt GM, Lillywhite HB, Meinwald J. Sequestered defensive toxins in tetrapod vertebrates: principles, patterns, and prospects for future studies. CHEMOECOLOGY 2012; 22:141-158. [PMID: 22904605 PMCID: PMC3418492 DOI: 10.1007/s00049-012-0112-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 07/14/2012] [Indexed: 12/16/2022]
Abstract
Chemical defenses are widespread among animals, and the compounds involved may be either synthesized from nontoxic precursors or sequestered from an environmental source. Defensive sequestration has been studied extensively among invertebrates, but relatively few examples have been documented among vertebrates. Nonetheless, the number of described cases of defensive sequestration in tetrapod vertebrates has increased recently and includes diverse lineages of amphibians and reptiles (including birds). The best-known examples involve poison frogs, but other examples include natricine snakes that sequester toxins from amphibians and two genera of insectivorous birds. Commonalities among these diverse taxa include the combination of consuming toxic prey and exhibiting some form of passive defense, such as aposematism, mimicry, or presumptive death-feigning. Some species exhibit passive sequestration, in which dietary toxins simply require an extended period of time to clear from the tissues, whereas other taxa exhibit morphological or physiological specializations that enhance the uptake, storage, and/or delivery of exogenous toxins. It remains uncertain whether any sequestered toxins of tetrapods bioaccumulate across multiple trophic levels, but multitrophic accumulation seems especially likely in cases involving consumption of phytophagous or mycophagous invertebrates and perhaps consumption of poison frogs by snakes. We predict that additional examples of defensive toxin sequestration in amphibians and reptiles will be revealed by collaborations between field biologists and natural product chemists. Candidates for future investigation include specialized predators on mites, social insects, slugs, and toxic amphibians. Comprehensive studies of the ecological, evolutionary, behavioral, and regulatory aspects of sequestration will require teams of ecologists, systematists, ethologists, physiologists, molecular biologists, and chemists. The widespread occurrence of sequestered defenses has important implications for the ecology, evolution, and conservation of amphibians and reptiles.
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Affiliation(s)
- Alan H. Savitzky
- Department of Biology, Utah State University, Logan UT, 84322-5305 USA
| | - Akira Mori
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto, 606-8502 Japan
| | - Deborah A. Hutchinson
- Department of Biology, Coastal Carolina University, P.O. Box 261954, Conway, SC 29528 USA
| | - Ralph A. Saporito
- Department of Biology, John Carroll University, University Heights, Ohio, 44118 USA
| | - Gordon M. Burghardt
- Department of Psychology, University of Tennessee, Knoxville, TN 37996-0900 USA
| | | | - Jerrold Meinwald
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca NY, 14853-1301 USA
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Todaro D, Watson GM. Force-dependent discharge of nematocysts in the sea anemone Haliplanella luciae (Verrill). Biol Open 2012; 1:582-7. [PMID: 23213451 PMCID: PMC3509440 DOI: 10.1242/bio.2012695] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Sea anemones discharge cnidae ('stinging capsules' including nematocysts) to capture prey and to defend themselves. In the present study, we tested the relationship between the force of test probes striking feeding tentacles and discharge of microbasic p-mastigophore nematocysts into the test probes. In seawater alone, the response curve is bimodal with maximal discharge observed at 0.33 and 1.10 millinewtons (mN) and with minimal discharge at 1.50 mN. Upon activating chemoreceptors for N-acetylated sugars, maximal discharge is observed across a broad range of smaller forces from 0.16 to 0.9 mN before decreasing to a minimum at 1.50 mN. Likewise, in the presence of nearby vibrations at key frequencies, maximal discharge is observed over a broad range of smaller forces before decreasing to a minimum at 1.50 mN. It appears that sensory input indicating proximity of potential prey expands the range of small forces of impact that stimulate maximal discharge (i.e. to less than 1.10 mN) but not at larger forces of impact (i.e. at approximately 1.50 mN). Thus, contact by small prey would stimulate maximal discharge, and all the more so if such contact is accompanied by specific odorants or by vibrations at specific frequencies. Nevertheless, anemones would not maximally discharge nematocysts into large animals that blunder into contact with their tentacles.
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Affiliation(s)
| | - Glen M. Watson
- Department of Biology, University of Louisiana at Lafayette, Lafayette, LA 70504-2451, USA
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Morabito R, Marino A, La Spada G. Nematocytes' activation in Pelagia noctiluca (Cnidaria, Scyphozoa) oral arms. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2012; 198:419-26. [PMID: 22526110 DOI: 10.1007/s00359-012-0720-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 03/12/2012] [Accepted: 03/14/2012] [Indexed: 12/23/2022]
Abstract
Nematocytes' discharge is triggered to perform both defense and predation strategies in cnidarians and occurs under chemico-physical stimulation. In this study, different compounds such as amino acids and proteins (mucin, albumin, poly-L: -lysine, trypsin), sugars and N-acetylate sugars (N-acetyl neuraminic acid, N-acetyl galactosamine, sucrose, glucose, agarose and trehalose), nucleotides (ATP and cAMP), were tested as chemosensitizers of nematocyte discharge in the oral arms of the scyphozoan Pelagia noctiluca, particularly abundant in the Strait of Messina (Italy). Excised oral arms were submitted to a combined chemico-physical stimulation by treatment with different compounds followed by mechanical stimulation by a non-vibrating test probe. Discharge induced by a chemico-physical stimulation was more significant than that obtained after mechanical stimulation alone. A chemosensitizing mechanism, with a dose-dependent effect, was observed after treatment with sugars, amino compounds such as glutathione, nucleotides and mucin, according to that already seen in sea anemones. Such findings suggest that, though Anthozoa and Scyphozoa exhibit different divergence times during the evolutionary process, the discharge activation exhibits common features, probably derived from their last common ancestor.
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Affiliation(s)
- R Morabito
- Department of Cognitive Sciences, Via Concezione 8, 98100, Messina, Italy.
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Scappaticci A, Kahn F, Kass-Simon G. Nematocyst discharge in Hydra vulgaris: Differential responses of desmonemes and stenoteles to mechanical and chemical stimulation. Comp Biochem Physiol A Mol Integr Physiol 2010; 157:184-91. [DOI: 10.1016/j.cbpa.2010.06.177] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 06/15/2010] [Accepted: 06/16/2010] [Indexed: 11/15/2022]
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Abstract
Although toxic, physically destructive, and produced solely by cnidarians, nematocysts are acquired, stored, and used by some predators of cnidarians. Despite knowledge of this phenomenon for well over a century, little empirical evidence details the mechanisms of how (and even why) these organisms use organelles of cnidarians. However, in the past 20 years a number of published experimental investigations address two of the fundamental questions of nematocyst acquisition and use by cnidarian predators: (1) how are cnidarian predators protected from nematocyst discharge during feeding; and (2) how are the nematocysts used by the predator?
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Affiliation(s)
- Paul G Greenwood
- Department of Biology, Colby College, Waterville, ME 04901, USA.
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Mebs D. Chemical biology of the mutualistic relationships of sea anemones with fish and crustaceans. Toxicon 2009; 54:1071-4. [PMID: 19268681 DOI: 10.1016/j.toxicon.2009.02.027] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fish species of the genera Amphiprion and Premnas (Perciformes: Pomacentridae) as well as various crustaceans seek protection from predators among the tentacles of sea anemones, where they live essentially unharmed from stinging by the host's nematocysts. The mucous coats of anemonefish and crustaceans have been suggested as mechanisms that prevent the discharge of the nematocysts upon contact. Whereas some fish species seem to produce their own protecting mucous coating, others may acquire mucus from the sea anemone during an acclimation period, as crustaceans do. Whether the natural or acquired mucus layers contain components that inhibit nematocyst discharge or simply lack compounds stimulating the stinging cell's exocytosis is still unknown.
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Affiliation(s)
- Dietrich Mebs
- Zentrum der Rechtsmedizin, University of Frankfurt, Kennedyallee 104, D-60596 Frankfurt, Germany.
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Martin R, Hild S, Walther P, Ploss K, Boland W, Tomaschko KH. Granular chitin in the epidermis of nudibranch molluscs. THE BIOLOGICAL BULLETIN 2007; 213:307-315. [PMID: 18083970 DOI: 10.2307/25066648] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Chitin is usually found in stiff extracellular coatings typified by the arthropod exoskeleton, and is not associated with the soft, flexible mollusc skin. Here, we show, however, that chitin in nudibranch gastropods (Opisthobranchia, Mollusca) occurs as intracellular granules that fill the epidermal cells of the skin and the epithelial cells of the stomach. In response to nematocysts fired by tentacles of prey Cnidaria, the epidermal cells of eolid nudibranchs (Aeolidacea) release masses of chitin granules, which then form aggregates with the nematocyst tubules, having the effect of insulating the animal from the deleterious action of the Cnidaria tentacles. Granular chitin, while protecting the animal, does not interfere with the suppleness and flexibility of the skin, in contrast to the stiffness of chitin armor. The specialized epidermis enables nudibranchs to live with and feed on Cnidaria.
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Affiliation(s)
- Rainer Martin
- Central Facility for Electron Microscopy, University of Ulm, Albert-Einstein-Allee 11, D 89069 Ulm, Germany.
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Abstract
BACKGROUND Jellyfish stings are a common occurrence among ocean goers worldwide with an estimated 150 million envenomations annually. Fatalities and hospitalizations occur annually, particularly in the Indo-Pacific regions. A new topical jellyfish sting inhibitor based on the mucous coating of the clown fish prevents 85% of jellyfish stings in laboratory settings. The field effectiveness is unknown. The objective is to evaluate the field efficacy of the jellyfish sting inhibitor, Safe Sea. METHODS A double-blind, randomized, placebo-controlled trial occurred at the Dry Tortugas National Park, FL, USA and Sapodilla Cayes, Belize. Participants were healthy volunteers planning to snorkel for 30 to 45 minutes. Ten minutes prior to swimming, each participant was directly observed applying a blinded sample of Safe Sea (Nidaria Technology Ltd, Jordan Valley, Israel) to one side of their body and a blinded sample of Coppertone (Schering-Plough, Kenilworth, NJ, USA) to the contralateral side as placebo control. Masked 26 g samples of both Safe Sea SPF15 and Coppertone SPF15 were provided in identical containers to achieve 2 mg/cm(2) coverage. Sides were randomly chosen by participants. The incidence of jellyfish stings was the main outcome measure. This was assessed by participant interview and examination as subjects exited the water. RESULTS A total of 82 observed water exposures occurred. Thirteen jellyfish stings occurred during the study period for a 16% incidence. Eleven jellyfish stings occurred with placebo, two with the sting inhibitor, resulting in a relative risk reduction of 82% (95% confidence interval: 21%-96%; p= 0.02). No seabather's eruption or side effects occurred. CONCLUSIONS Safe Sea is a topical barrier cream effective at preventing >80% jellyfish stings under real-world conditions.
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Affiliation(s)
- David R Boulware
- Division of Infectious Disease and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, 55455, USA.
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