On the Functions and Mode of Action of the Nematocysts of Hydra.

Ewer, R. F.; Fox, H. Munro

doi:10.1111/j.1096-3642.1947.tb00524.x

Cited by 113 publications

(47 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Hydra is notably able to move via a complex array of movements, including rare instances of somersaulting (alternative attachment and release of the foot and tentacles combined with contraction and extension of the body column, Figure 3B) (Trembley, 1744; Ewer and Fox, 1947). Many sea anemones (Actiniaria) are able to perform creeping using the muscles of their pedal disk (McClendon, 1906), their tentacles (Ross and Sutton, 1961) or to burrow using peristaltic movements (Williams, 2003).…”

Section: Cnidarian Muscle Functionsmentioning

confidence: 99%

Diversity of Cnidarian Muscles: Function, Anatomy, Development and Regeneration

Leclère

Röttinger

2017

Front. Cell Dev. Biol.

View full text Add to dashboard Cite

The ability to perform muscle contractions is one of the most important and distinctive features of eumetazoans. As the sister group to bilaterians, cnidarians (sea anemones, corals, jellyfish, and hydroids) hold an informative phylogenetic position for understanding muscle evolution. Here, we review current knowledge on muscle function, diversity, development, regeneration and evolution in cnidarians. Cnidarian muscles are involved in various activities, such as feeding, escape, locomotion and defense, in close association with the nervous system. This variety is reflected in the large diversity of muscle organizations found in Cnidaria. Smooth epithelial muscle is thought to be the most common type, and is inferred to be the ancestral muscle type for Cnidaria, while striated muscle fibers and non-epithelial myocytes would have been convergently acquired within Cnidaria. Current knowledge of cnidarian muscle development and its regeneration is limited. While orthologs of myogenic regulatory factors such as MyoD have yet to be found in cnidarian genomes, striated muscle formation potentially involves well-conserved myogenic genes, such as twist and mef2. Although satellite cells have yet to be identified in cnidarians, muscle plasticity (e.g., de- and re-differentiation, fiber repolarization) in a regenerative context and its potential role during regeneration has started to be addressed in a few cnidarian systems. The development of novel tools to study those organisms has created new opportunities to investigate in depth the development and regeneration of cnidarian muscle cells and how they contribute to the regenerative process.

show abstract

Section: Cnidarian Muscle Functionsmentioning

confidence: 99%

Diversity of Cnidarian Muscles: Function, Anatomy, Development and Regeneration

Leclère

Röttinger

2017

Front. Cell Dev. Biol.

View full text Add to dashboard Cite

show abstract

“…That substances produced by the prey, as mucus, can inhibit nematocyst discharge has been already demonstrated by Ewer (1947) and Grosvenor and Kass-Simon (1987), showing that substances released from Artemia nauplii and binding to GSH receptors inhibit feeding behavior, nematocyst discharge and mouth opening, and induce post-prandial tentacle along with body contractions. Mucus has also been recognized as an inhibitor of nematocyst discharge in sea anemone and clownfish interaction (Lubbock 1979) and in sea anemone and nudibranch interaction (Mauch and Elliott 1997;Greenwood et al 2004).…”

Section: Proteinsmentioning

confidence: 87%

Nematocytes’ activation in Pelagia noctiluca (Cnidaria, Scyphozoa) oral arms

Morabito

Marino²,

Spada³

2012

J Comp Physiol A

View full text Add to dashboard Cite

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.

show abstract

“…Indeed, their discharge is responsible for the immobilisation of the preys, but also for the attachment of the tentacles to the substrate during walking (Ewer, 1947;Tardent, 1995). Since their initial description (Weill, 1934a, b), the study of their biogenesis and their physiology led to surprising discoveries as for example the unique speed of their discharge (Holstein and Tardent, 1984) or the negative regulation of their discharge by opsins (Plachetzki et al, 2012).…”

Section: The Nematocyst a Sophisticated Organelle With Outstanding Bmentioning

confidence: 99%

“…All these toxic proteins are supposed to have diverged from non-toxic proteins, representing thus convergent evolutionary events between different venomous species. Moreover the composition of the venom is likely different between the different types of nematocysts, either involved in the feeding response (stenoteles, desmonemes), or in defence (holotrichous isorhizae) or in locomotion (atrichous isorhizae) (Ewer, 1947). Therefore further studies should be performed on purified homogenous populations of nematocysts.…”

Section: The Chemical Arsenal and The Chemical Landscape Of Hydramentioning

confidence: 99%

Hydra, a fruitful model system for 270 years

Galliot¹

2012

Int. J. Dev. Biol.

155

113

View full text Add to dashboard Cite

The discovery of Hydra regeneration by Abraham Trembley in 1744 promoted much scientific curiosity thanks to his clever design of experimental strategies away from the natural environment. Since then, this little freshwater cnidarian polyp flourished as a potent and fruitful model system. Here, we review some general biological questions that benefitted from Hydra research, such as the nature of embryogenesis, neurogenesis, induction by organizers, sex reversal, symbiosis, aging, feeding behavior, light regulation, multipotency of somatic stem cells, temperature-induced cell death, neuronal transdifferentiation, to cite only a few. To understand how phenotypes arise, theoricists also chose Hydra to model patterning and morphogenetic events, providing helpful concepts such as reaction-diffusion, positional information, and autocatalysis combined with lateral inhibition. Indeed, throughout these past 270 years, scientists used transplantation and grafting experiments, together with tissue, cell and molecular labelings, as well as biochemical procedures, in order to establish the solid foundations of cell and developmental biology. Nowadays, thanks to transgenic, genomic and proteomic tools, Hydra remains a promising model for these fields, but also for addressing novel questions such as evolutionary mechanisms, maintenance of dynamic homeostasis, regulation of stemness, functions of autophagy, cell death, stress response, innate immunity, bioactive compounds in ecosystems, ecotoxicant sensing and science communication. KEY WORDS: historical perspective, transplantation, modeling, developmental reactivation, Hydra regeneration, multipotency, stemness, symbiosis, environmentThe heuristic value of the Hydra model systemIn the early 18th century the word biology was not yet in use but the nature of living organisms and their evolutionary relationships was the focus of interest for philosophers and naturalists, as evidenced by their pioneering efforts to develop new tools such as microscopes that would allow finer observation (Palm, 1996). The microscopic observation of organisms taken in the field undoubtedly helped develop morphological keys to sort between the animal and vegetal kingdoms and to group them into phyla (Linnaeus, 1758). Among the ambiguous species that could not be easily classified were the seawater corals that looked like flowers (Watson, 1753;McConnell, 1990) and the freshwater Hydra polyp that was considered to exhibit both animal and vegetal features. For example, Hydra easily reproduces asexually through budding, a trait frequently assigned to plants or fungi.Having observed some Hydra polyps in a pond, Abraham Trembley (1710-1784) (who had received a PhD in mathematics from the University of Geneva (Switzerland) and was now educating the children of the Count of Bentick in the Netherlands) decided Int. J. Dev. Biol. 56: 411-423 (2012) to solve that problem by testing their capacity to regenerate, assuming that if Hydra regenerates, then it should be considered a plant, but if it does...

show abstract

On the Functions and Mode of Action of the Nematocysts of Hydra.

Cited by 113 publications

References 6 publications

Diversity of Cnidarian Muscles: Function, Anatomy, Development and Regeneration

Diversity of Cnidarian Muscles: Function, Anatomy, Development and Regeneration

Nematocytes’ activation in Pelagia noctiluca (Cnidaria, Scyphozoa) oral arms

Hydra, a fruitful model system for 270 years

Contact Info

Product

Resources

About