nematocyst


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Related to nematocyst: basal disc

nem·a·to·cyst

(nem'ă-tō-sist),
A stinging cell of coelenterates consisting of a poison sac and a coiled barbed sting capable of being ejected and penetrating the skin of an animal on contact; of considerable consequence in large jellyfish and in the Portuguese man-of-war which possess large numbers of these stinging cells that can cause great pain and even death.
Synonym(s): cnida, cnidocyst
[nemato- + G. kystis, bladder]

nematocyst

(nĕm′ə-tə-sĭst′, nĭ-măt′ə-)
n.
A capsule within specialized cells in the tentacles of cnidarians, such as jellyfish and corals, containing a barbed, threadlike tube that delivers a toxic sting to predators and prey.

nem′a·to·cys′tic adj.

nem·a·to·cyst

(nem'ă-tō-sist)
A stinging cell of coelenterates consisting of a poison sac and a coiled barbed sting capable of being ejected and penetrating the skin of an animal on contact; of considerable consequence in large jellyfish and in the Portuguese man-of-war whose large numbers of these stinging cells can cause great pain and even death.
[nemato- + G. kystis, bladder]

nematocyst

A coiled, tube-like stinging organ of various coelenterates, such as jellyfish. The nematocyst injects a chemical paralyzant.
Nematocystclick for a larger image
Fig. 227 Nematocyst . Nematocysts of Hydra. (a) Discharged. (b) Undischarged.

nematocyst

a structure formed of a hollow thread within a bladder in the CNIDOBLAST or thread cell of COELENTERATES. On stimulation, for example by prey, the thread is everted. Several types exist, such as stinging cells that inject poisonous substances into the prey through the thread, and sticky cells which exude a sticky substance which causes the prey to adhere to the coelenterate tentacle. Enormous numbers are present on the tentacles of some forms and nematocysts are responsible for the jellyfish ‘sting’. Such cells can be utilized by other organisms, for example flatworms preying on coelenterates. The nematocysts migrate to the surface layer of a flatworm which has fed on the coelenterate and are used by the flatworms in exactly the same way as coelenterates use them.
References in periodicals archive ?
A guideline to nematocyst nomenclature and classification, and some notes on the systematic value of nematocysts.
Although most venoms are harmless, the venoms of some species may cause local effects, including immediate and delayed inflammatory-allergic responses (pain, swelling, itching, and localized erythema due to skin contact with nematocysts).
Nematocysts were isolated from the dissected tentacles as described in a Bloom method with slight modification [25].
When nematocysts were deactivated, the pompano failed to discriminate between clams with and without hydroids, suggesting that nematocysts are responsible for deterring this predator.
Nematocyst compliment comprising isorhizas about 5.9-6.5 x 1.5-1.9 [micron]m and microbasic mastigophores of three distinct sizes; (i) small 6.3-8.0 x 1.9-2.5 [micron]m; (ii) medium 8.5-9.3 x 2.8-3.2 [micron]m; and (iii) large 13.6-16.8 x 3.3-4.1 [micron]m.
Hydras have few predators, due to the presence of nematocysts and their low mobility (Massaro et al., 2013).
I would like to thank Robert Burn and Melanie Mackenzie for their assistance with collecting specimens, Claudia Mills for the many emails about these animals, Jeanette Watson for teaching me how to examine the nematocysts, John Kuo for kindly sending me his paper on Heterozostera, Hugh Kirkman for confirming the species of seagrass present at the Jawbone and, finally, Leon Altoff for kneeling for long periods in very cold water in the middle of winter to capture images.
Slinging nematocysts within the anemone tentacles contain the venom beta phospholipase A2 and are used to stun prey or defend against potential predators (Grotendorst & Hessinger 2000).
Immature nematocyst incorporation by the aeolid nudibranch Spurilla neapolitana.
Furthermore, the cnidome (nematocyst composition) of adult A.
However, hydration may resolve situations such as that described by Gershwin (2006a: 7): "Every effort was made to study inverted and everted nematocysts; however, with fixed material, this was not always possible" improving the quality of nematocyst surveys.