Puncture mechanics of cnidarian cnidocysts: a natural actuator

Oppegard, Shawn C.; Anderson, Peter; Eddington, David T.

doi:10.1186/1754-1611-3-17

Cited by 10 publications

(12 citation statements)

References 34 publications

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“…; Oppegard et al. ). The discharge of these structures is triggered by the stimulation of the cnidocil (a modified cilium on the outside of the cnidocyte) by chemical and/or mechanical mechanisms (Cormier & Hessinger ; Östman ; Özbek et al.…”

Section: What Are Nematocysts?mentioning

confidence: 96%

“…Nematocysts are small venom-filled capsules containing an eversible tubule ( Fig. 2B), often with spines or barbs, that can be discharged into the tissues of other organisms with very high accelerations, up to 5 million g (N€ uchter et al 2006;Oppegard et al 2009). The discharge of these structures is triggered by the stimulation of the cnidocil (a modified cilium on the outside of the cnidocyte) by chemical and/or mechanical mechanisms (Cormier & Hessinger 1980;€ Ostman 2000;€ Ozbek et al 2009).…”

Section: What Are Nematocysts?mentioning

confidence: 99%

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Sequestration of nematocysts by divergent cnidarian predators: mechanism, function, and evolution

Goodheart

Bely

2016

Invertebrate Biology

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Animals have evolved diverse mechanisms to protect themselves from predators. Although such defenses are typically generated endogenously, some species have evolved the ability to acquire defenses by sequestering defensive chemicals or structures from other species. Chemical sequestration is widespread among animals, but the ability to sequester entire structures, such as organelles, appears to be rare. Here, we review information on the seques-tration of functional nematocysts, the stinging organelles produced by Cnidaria, by divergent predators. Nematocyst sequestration has evolved multiple times, having been documented in Ctenophora, Acoelomorpha, Platyhelminthes, and Mollusca. For each of these phyla, we review the phylogenetic distribution, mechanisms, and possible functions of nematocyst sequestration. We estimate that nematocyst sequestration has evolved 9-17 times across these four phyla. Although data on the mechanism of sequestration remain limited, similarities across several groups are evident. For example, in multiple groups, nematocysts are transported within cells from the gut to peripheral tissues, and certain types of nematocysts are selectively sequestered over others, suggesting convergent evolution in some aspects of the sequestration process across phyla. Similarly, although the function of nematocyst sequestra-tion has not been well documented, several studies do suggest that the nematocysts seques-tered by these groups are effective for defense. We highlight several traits that are common to Ctenophora, Acoelomorpha, Platyhelminthes, and Mollusca and suggest hypotheses for how these traits could have played a role in the evolution of nematocyst sequestration. Finally, we propose a generalized working model for the steps that may lead to the evolution of nemato-cyst sequestration and discuss important areas for future research.

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Section: What Are Nematocysts?mentioning

confidence: 96%

Section: What Are Nematocysts?mentioning

confidence: 99%

Sequestration of nematocysts by divergent cnidarian predators: mechanism, function, and evolution

Goodheart

Bely

2016

Invertebrate Biology

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“…In particular, some taxa within Cladobranchia possess the ability to sequester nematocysts from their cnidarian prey. Termed kleptocnides once sequestered, these small venom-filled capsules contain an eversible tubule, often with spines or barbs, that can be discharged into the tissues of other organisms [ 16 , 17 ] and are used by members of Cnidaria to sting predators and capture food [ 18 ]. The sequestration of cnidarian nematocysts occurs primarily in one group of cladobranchs, Aeolidida (commonly referred to as aeolids), which appears to be monophyletic [ 19 ].…”

Section: Introductionmentioning

confidence: 99%

Comparative morphology and evolution of the cnidosac in Cladobranchia (Gastropoda: Heterobranchia: Nudibranchia)

et al. 2018

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BackgroundA number of shelled and shell-less gastropods are known to use multiple defensive mechanisms, including internally generated or externally obtained biochemically active compounds and structures. Within Nudipleura, nudibranchs within Cladobranchia possess such a special defense: the ability to sequester cnidarian nematocysts – small capsules that can inject venom into the tissues of other organisms. This ability is distributed across roughly 600 species within Cladobranchia, and many questions still remain in regard to the comparative morphology and evolution of the cnidosac – the structure that houses sequestered nematocysts (called kleptocnides). In this paper, we describe cnidosac morphology across the main groups of Cladobranchia in which it occurs, and place variation in its structure in a phylogenetic context to better understand the evolution of nematocyst sequestration.ResultsOverall, we find that the length, size and structure of the entrance to the cnidosac varies more than expected based on previous work, as does the structure of the exit, the musculature surrounding the cnidosac, and the position and orientation of the kleptocnides. The sequestration of nematocysts has originated at least twice within Cladobranchia based on the phylogeny presented here using 94 taxa and 409 genes.ConclusionsThe cnidosac is not homologous to cnidosac-like structures found in Hancockiidae. Additionally, the presence of a sac at the distal end of the digestive gland may have originated prior to the sequestration of nematocysts. This study provides a more complete picture of variation in, and evolution of, morphological characters associated with nematocyst sequestration in Cladobranchia.Electronic supplementary materialThe online version of this article (10.1186/s12983-018-0289-2) contains supplementary material, which is available to authorized users.

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“…These nematocysts have harpoon-like stylets that are used for venom injection (Holstein and Tardent, 1984). When triggered by a combination of chemical and mechanical cues (Pantin, 1942;Lubbock, 1979;Arai, 1997), the stylets are discharged at incredible speeds, likely driven by a combination of osmotic pressure and mechanical energy storage in the capsule walls (although the precise mechanisms are still debated) (Godknecht and Tardent, 1988;Nüchter et al, 2006;Oppegard et al, 2009). These harpoon-like structures are barbed and expendable once they have delivered their sting.…”

Section: Injection/removalmentioning

confidence: 99%

“…Examples of biological puncture mechanisms can be found in numerous phyla and span several orders of magnitude in size (from the beaks of great blue heron to the stinging cells on jellyfish) and a range of speeds (from passive puncturing in cacti to the ultrafast puncturing in mantis shrimp). This diversity of puncture mechanics has drawn the attention of engineers looking to design better puncture tools (Ramasubramanian, et al, 2008;Oppegard et al, 2009;Frasson et al, 2012), as well as materials that can resist penetration (Chintapalli et al, 2014). In many cases, nature still outperforms our technology: in order to pierce human skin, ultra-sharp artificial microneedles require three times the force needed by a mosquito (Kong and Wu, 2009).…”

Section: Introductionmentioning

confidence: 99%

Making a point: shared mechanics underlying the diversity of biological puncture

Anderson

2018

Journal of Experimental Biology

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A viper injecting venom into a target, a mantis shrimp harpooning a fish, a cactus dispersing itself via spines attaching to passing mammals; all these are examples of biological puncture. Although disparate in terms of materials, kinematics and phylogeny, all three examples must adhere to the same set of fundamental physical laws that govern puncture mechanics. The diversity of biological puncture systems is a good case study for how physical laws can be used as a baseline for comparing disparate biological systems. In this Review, I explore the diversity of biological puncture and identify key variables that influence these systems. First, I explore recent work on biological puncture in a diversity of organisms, based on their hypothesized objectives: gripping, injection, damage and defence. Variation within each category is discussed, such as the differences between gripping for prey capture, gripping for dispersal of materials or gripping during reproduction. The second half of the Review is focused on specific physical parameters that influence puncture mechanics, such as material properties, stress, energy, speed and the medium within which puncture occurs. I focus on how these parameters have been examined in biology, and how they influence the evolution of biological systems. The ultimate objective of this Review is to outline an initial framework for examining the mechanics and evolution of puncture systems across biology. This framework will not only allow for broad biological comparisons, but also create a baseline for bioinspired design of both tools that puncture efficiently and materials that can resist puncture.

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Puncture mechanics of cnidarian cnidocysts: a natural actuator

Cited by 10 publications

References 34 publications

Sequestration of nematocysts by divergent cnidarian predators: mechanism, function, and evolution

Sequestration of nematocysts by divergent cnidarian predators: mechanism, function, and evolution

Comparative morphology and evolution of the cnidosac in Cladobranchia (Gastropoda: Heterobranchia: Nudibranchia)

Making a point: shared mechanics underlying the diversity of biological puncture

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