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| | EM PROJECT: CHARLES MOFFET |
 | | Discharged nematocyst lodged in the cuticle of Artemia prey. | | | Within the cnidocytes is the nematocyst which is an inverted tubule armed at one end with a harpoon exhibiting hooks and spines (Watson 1988). | | | The origin, formation, and function of the laminations is currently unknown, but it presumably facilitates the process of nematocyst discharge. |
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http://www.csulb.edu/~zedmason/emprojects/charlie/moffet.html
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| | eMJA: Pereira et al, Pressure immobilisation bandages in first-aid treatment of jellyfish envenomation: current ... |
| | Given that the physical processes behind nematocyst discharge in all jellyfish are similar, and that nematocyst discharge operates similarly, there is sufficient reason to believe that the use of PIB on any jellyfish sting site may exacerbate the envenomation, irrespective of whether vinegar has been applied. | | | Until evidence to the contrary is available, we recommend that applying PIB is not part of the management of this life-threatening condition. | | | Our experiment shows clearly that further venom is expressed by applying pressure (equivalent to that of PIB) to discharged nematocysts. |
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http://www.mja.com.au/public/issues/173_11_041200/pereira/pereira.html
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| | Phylum Cnidaria |
| | Discharge of nematocysts have been found in response to heat and tactile stimulation. | | | Nematocysts have been observed to have other functions. | | | These types of nematocysts are fired under different conditions and circumstances. |
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http://comenius.susqu.edu/bi/322/IZLecture9.htm
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| | World Intellectual Property Organization |
| | The average number of nematocysts that were counted on a skin sample that was treated with the ointment base alone was 27+/-10 nematocysts. | | | The method of Claim 27, wherein the nematocysts are discharged from an organism selected from the group consisting of Hydrozoa, Anthozoa or Schyphoza. | | | technique was used to monitor the number of nematocysts that penetrated into the skin. |
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http://www.wipo.int/ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=01/37778.010531&ELEMENT_SET=DECL
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| | Wonders of the Sea: Cnidarians |
| | The nematocyst is fired either by the tentacle touching prey, or in some cases by a nerve impulse from the animal telling it to fire. | | | Most Cnidarian’s nematocysts are not harmful to humans, as the stinger cannot penetrate sufficiently into human skin to inflict any harm. | | | There are some jellyfish, however, which can deliver extremely painful, and in a few cases, even fatal stings to humans. |
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http://www.oceaninn.com/guides/cnidarians.htm
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| | EM PROJECT: MICHELLE JOHNSON AND MISTY BORJA |
| | Prior to feeding, the cerata of all nudibranchs, excluding the control group, were stroked manually with a finger to stimulate discharge of the resident nematocysts and promote the incorporation of nematocysts from the prey items. | | | The most unusual aspect of this defense system is that the nudibranch cannot synthesize its own nematocysts but must rely upon acquiring them from its consumed prey which is composed mainly of coelenterates. | | | 2) Kepner, W.A. The manipulation of the nematocysts of Pennaria tiarella by Aeolis pilata. |
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http://www.csulb.edu/~zedmason/emprojects/misty/nudibr.html
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| | Biochemistry of the Nematocyst |
| | Other authors propose, however, that nematocyst discharge is more analogous to neurotransmitter release in nerves as a calcium-dependent exocytosis that is mediated by voltage-gated calcium channels (Kass-Simon and Scappaticci, 2002). | | | Despite all of this gathered knowledge, it is still not conclusively know if nematocyst behavior acts independently of central control or nervous systems within the Cnidarian organisms, or if there is slight or complete control. | | | Sea anemones were subjected to different environmental conditions, particularly different salinities and food availability in a study performed by Greenwood et al. |
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http://www.studentsasteachers.com/website/Cnidarian%20Defense/Biochemistry%20of%20the%20Nematocyst.htm
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| | xm2.html |
| | Comment: As this person notes, structured water or phase transition theory doesn't explain the observation that pressure inside nematocysts is very high -- a detail Pollack didn't mention because it is wasn't relevant to the point he was trying to make, and something he may not have even known. | | | One might believe that there is a correlation between pressure and expansion, but the high pressure still does not account for the triggering mechanism that creates explosive activities inside the vesicle. | | | This is not to say that there is necessarily no role at all for phase transition. |
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http://www.cwu.edu/~verheys/320w02/xm2key.html
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| | Things with Stings… by Ronald L. Shimek, Ph.D. - Reefkeeping.com |
| | Generally, the discharge of a single nematocyst has very little effect; however, nematocysts don't exist singly. | | | Even though the tip of the thread is minute, with such acceleration driving it, it can punch through almost all biological surfaces, including some mollusk shells, arthropod exoskeletons, and human skin. | | | Here is a link to some information about it and some rather gruesome images. |
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http://www.reefkeeping.com/issues/2002-07/rs/index.htm
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| | Shoals Marine Laboratory - Undergraduate Research Opportunities |
| | Given the uniqueness of these nematocysts as prey defense, understanding the intricacies of nudibranch predator-prey interactions is a critical step in explaining their functional role in marine communities. | | | This study focuses on laboratory manipulations of both nudibranchs and their prey. | | | Depending on the prey they consume, nudibranchs sequester different kinds of nematocysts. |
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http://www.sml.cornell.edu/research/pr-uo-uspn.htm
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| | Fwd: Post Doc available |
| | Mariscal has done some ultrastructure work on nematocysts maybe there are some leads for you to follow in Mariscal, R.N., R.B. McLean and C. | | | =93Identification of Chironex fleckeri=20 envenomation by nematocyst recovery from skin.=94 Medical Journal of=20 Australia 162: 478-480. | | | =93Identification of Chironex fleckeri envenomation by nematocyst recovery from skin.=94 Medical Journal of Australia 162: 478-480. |
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http://maillists.uci.edu/mailman/public/cnidaria/2001-December.txt
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| | eMedicine - Jellyfish Stings : Article by David Cheng, MD |
| | Treatment usually consists of (1) nematocyst deactivation, (2) pain control, (3) local wound care, (4) symptomatic treatment, (5) support of the vital organs in which function is affected, and (6) use of antivenin for box jellyfish envenomation. | | | While knowledge of location, time, and resulting skin pattern of the encounter may aid clinical identification of the envenoming jellyfish species, true identification is made only by actual visualization of the jellyfish, by microscopic examination of the nematocysts, or by serologic testing. | | | This pressurized process has a high internal hydrostatic pressure of 150 atm that causes the ejection to occur within 3 milliseconds, with an acceleration power of 40,000g and a force of penetration of 20-33 kPa. |
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http://www.emedicine.com/derm/topic199.htm
(5443 words)
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| | eMJA: Severity of Irukandji syndrome and nematocyst identification from skin scrapings |
| | Identification of Chironex fleckeri envenomation by nematocyst recovery from skin. | | | Of 50 patients who had skin scrapings, 39 had nematocysts consistent with Carukia barnesi. | | | (1) To identify the causative jellyfish species by examining skin scrapings in patients presenting to Cairns Base Hospital with marine stings, and (2) to describe clinical outcomes of those with Irukandji syndrome and those in whom nematocysts were identified from skin scrapings. |
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http://www.mja.com.au/public/issues/178_01_060103/huy10611_fm.html
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| | Nematocyst dicharge |
| | Lenhoff and Lenhoff (1988) relate that overall function and morphology of the nematocysts were detected not until the mid-nineteenth century when the necessary techniques of histology had been developed. | | | The time course of the rapid process of nematocyst discharge has been visualized in Hydra vulgaris by | | | The nematocyst is an organelle of the nematocyte, which developes from the (immature) nematoblast. |
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http://www.fh-jena.de/%7Egitter/x_nemato.html
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| | Nikon MicroscopyU Movie Gallery: Hydra (Coelenterata) Video No. 5 |
| | The fourth kind of nematocyst has spines running along the thread and is probably used to defend the hydra against potential predators. | | | With a firm hold on its prey, the hydra then envelops the organism, like a sock being pulled over a foot, and consumes it. | | | Simple as these organisms are, their nematocysts are one of the most complex structures in the animal world. |
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http://www.microscopyu.com/moviegallery/pondscum/coelenterata/hydra/t1/hydra05.html
(248 words)
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| | Cnidocyte - Wikipedia, the free encyclopedia |
| | The discharge is also accompanied by stimulation of specific chemoreactors on the animal's body. | | | Some nematocysts puncture the skin or exoskeleton of an organism and inject a paralyzing toxin. | | | Nematocyst discharge is one of the fastest biological processes and takes not more than few microseconds. |
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http://en.wikipedia.org/wiki/Nematocyst
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| | The Sea Slug Forum - Re: Nudibranch/Nematocyst interaction |
| | • Conklin, E.J. & Mariscal, R.N. (1977) Feeding behavior, ceras structure, and nematocyst storage in the aeolid nudibranch, Spurilla neapolitana (Mollusca). | | | There are few published studies on the turnover rate of nudibranch nematocysts. |
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http://www.seaslugforum.net/find.cfm?id=2686
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| | A switch in disulfide linkage during minicollagen assembly in Hydra nematocysts |
| | Vesicles fuse at the tip of the tubule (arrows). | | | The stages of morphogenesis are outlined for a stenotele but also apply to a desmoneme or an isorhiza. | | | This nematocyst is almost mature, and represents the same stages as the ones marked by arrows in (C). |
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http://www.nature.com/emboj/journal/v20/n12/fig_tab/7593804ft.html
(1142 words)
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| | Encyclopedia: Animal |
| | The tiny phylum Placozoa is similar, but individuals do not have a permanent digestive chamber. | | | Species About 120; see text Anemone (Anemone) (from the Gr. | | | Binomial name Trichoplax adhaerens F.E. von Schultze, 1883 Trichoplax adhaerens is a simple balloon-like marine animal with a body cavity filled with pressurized fluid. |
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http://www.nationmaster.com/encyclopedia/Animal
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| | The Amazing Cnidoblast |
| | The nematocyst is located inside the one-celled Cnidoblast (pronounced Ny-doh-blast) which in turn is located on the tentacles of the coral polyp, which lives inside its calcareous cup. | | | Only those nematocysts located in the stimulated area are discharged. | | | There are at least 17 kinds of nematocysts. |
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http://www.scsoft.de/et/et2.nsf/KAP3View/2BCB3D6F97D7B531C125645A00008612
(474 words)
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| | Nematocysts |
| | Nematocysts are individual cells usually on the outer surface of the organism which have a variety of functions, most usually in defence or capture of prey species. | | | Nematocyst discharge is triggered by direct contact or other external stimulus. | | | Nematocysts can be specialised to carry out a number of functions within the organism these include; Sticking to surfaces and wrapping around objects, Penetrating surfaces or secreting proteinaceous toxins. |
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http://www.users.totalise.co.uk/~darrenbarton/id93.htm
(212 words)
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| | The Anemones, Corals and Jellyfish (Phylum Cnidaria) |
| | When the nematocyst is discharged, the barbs penetrate the skin of the prey and a toxin can be injected. | | | Nematocysts, and their enclosing Cnidocysts come in about 24 different forms, the differences play a functional role in the classification of the phylum. | | | One of the most important distinguishing characteristics of the phylum are the Nematocysts. |
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http://www.earthlife.net/inverts/cnidaria.html
(1238 words)
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| | Glossary |
| | cnidoblast - a cell in the epidermis of cnidarians in which a nematocyst is developed. | | | nematocyst - a capsule within specialized cells (cnidoblasts) of certain cnidarians (such as jellyfish) containing a barbed, threadlike tube that delivers a paralyzing sting when propelled into attackers and prey; also called a stinging cell. |
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http://www.geology.wisc.edu/~museum/old/glossary.html
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| | NEMATOCYST |
| | Mechanical and chemical stimulation triggers the nematocyst to eject the needle-like thread. | | | Nematocyst is also used for defense, anchoring and sometimes locomotion. | | | The distinguishing feature of the cnidarinas is their nematocysts, which are abundant in their tentacles. |
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http://www.cc.u-ryukyu.ac.jp/~coral/Action/NEMATOCYST.htm
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| | The Sea Slug Forum - Cnidosac and nematocyst |
| | •Thompson, T.E. & Bennett,I (1969): Physalia nematocysts: utilized by mollusks for defense. | | | •Conklin, E.J. & Mariscal, R.N. (1977) Feeding behaviour, Ceras structure, and nematocyst storage in the aeolid Spurilla neapolitana (Mollusca). | | | and#8226;Allen, J.K. (1976) Function of nematocysts in Eol"> |
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http://www.seaslugforum.net/refcnido.htm
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| | Getting Nailed by Jellies - Undercurrent, September 2003 |
| | More than 13,000 species of corals, anemones, hydroids, and jellyfish can make your life an itchy, painful nightmare — and even kill. | | | Be aware, however, that these treatments can cause the nematocysts of certain jellyfish to fire, such as those of the Portuguese man o' war and lion's mane (Cyanea capillata). | | | It is designed to keep nematocysts from being activated and has both research and anecdotal reports of effectiveness. |
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http://www.undercurrent.org/UCnow/articles/Jellies200309.shtml
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| | Re: Do the darts on a sea anemone actually detach from the tentacles? |
| | Anyway, when the cnida is triggered to fire, the nematocyst is rapidly everted (turned inside out) and shot into the flesh of the prey. | | | The business end of the nematocyst can be armed with hooks, spines, or barbs, and some can inject toxins into the prey animal. | | | Once the thread is everted, it cannot be retrieved and recoiled back into the capsule, so nematocysts are definitely one-use-only structures. |
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http://www.madsci.org/posts/archives/apr2001/987118887.Zo.r.html
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| | Z250 - Best Bibliographies 2004-1 |
| | When a nematocyst fires, the skin of F. | | | Protective mechanisms against the action of nematocysts in the epidermis of Cratena peregrine and Flabellina affinis (Gastropoda, Nudibranchia). | | | Aeolid nudibranchs not only eat cnidarians, but they also live among their nematocyst-armed tentacles. |
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http://biodb.biology.ualberta.ca/courses.hp/zool250/BestBibs/biblio04-1.htm
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| | HMS Student Papers 1993 - A morphological study of a deep-sea Trachymedusa Benthocodon pedunculata (Bigelow, 1913) |
| | Gut analyses of medusae yielded copepods, amphipods, foramniferans, pycnogonid, and other unidentified organisms which show that the medusae are feeding on benthic and benthopelagic organisms. | | | This study investigates the gross morphology of the medusae, tentacle types, and nematocyst types. | | | Phase contrast microscopy and scanning electron microscopy were used to detect morphological differences between the inner and outer tentacles and also revealed two nematocyst types previously undescribed in the literature, the modified-aspirotle nematocyst and the modified-stenotele nematocyst. |
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http://www-sul.stanford.edu/depts/miller/student_papers/1993_3.html
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| | nematocyst - meaning and definition of the word. |
| | nematocyst - meaning and definition of the word. | | | You can double click on any word to find it's meaning when you see the help cursor. |
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http://dictionary.blintz.com/dictionary/nematocyst
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| | The Biological Bulletin: Response in nematocyst uptake by the nudibranch Flabellina verrucosa to the presence of ... |
| | Selection for nematocyst incorporation is a function of diet and prey choice, but ratios vary among nudibranchs feeding on a given diet, indicating that other factors may be involved. | | | Aeolid nudibranchs maintain nematocysts sequestered from their cnidarian prey for protection against predators. | | | Nematocyst uptake in the nudibranch Flabellina verrucosa collected from the southern Gulf of Maine was examined in response to various potential predators, including Crossaster papposus, Tautogolabrus adspersus, and... |
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http://highbeam.com/library/doc0.asp?docid=1G1:112022366&refid=ink_tptd_mag
(205 words)
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| | other cnidaria |
| | These tentacles are covered in stinging cells or nematocysts that have the primary function of attacking potential food organisms, however also assist the cnidarian in defending itself. | | | Tentacles are for defense and for moving food to the mouth. | | | Most Cnidaria possess a simple body with a single opening (acting as both mouth and anus) surrounded by a number of tentacles. |
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http://www.reefpix.com.au/guidecnidaria.html
(635 words)
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| | Jellyfishes |
| | Another interesting subject for the microscopist are the tentacles which are covered with cnidocysts which produce nematocysts. | | | At this time a nematocyst projects a sort of little harpoon which pierces the skin or exoskeleton of the prey and injects venom. | | | It's difficult to see the detail of a nematocyst (except with an electron microscope) but easy to make them discharge by adding a little vinegar to the slide. |
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http://www.microscopy-uk.org.uk/mag/artjun03/jmcmedusa.html
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| | Biological Bulletin, The: A nematocyst release response in the sea anemone tentacle.(Efferent Mechanisms of Discharging ... |
| | In this paper, we hypothesize a "nematocyst release response." Using methods we have developed to measure the strength of attachment of discharged nematocysts to the tentacles of... | | | A nematocyst release response in the sea anemone tentacle.(Efferent Mechanisms of Discharging Cnidae, part 2) | | | It is not known how the discharged nematocysts are released from the tentacles, and it is not known whether such release is under physiological control. |
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http://calbears.findarticles.com/p/articles/mi_hb1456/is_199810/ai_n6376022
(283 words)
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| | Neuroscience for Kids - Taking the Sting out of Jellyfish Stings |
| | This toxin results in a burning sensation and reddened skin. | | | Jellyfish use a barb-like structure called a nematocyst to inject toxin when they contact us. | | | In the movie "Finding Nemo," fish bounce off the bell-shaped tops of the jellyfish to move through them safely; humans are not so agile -- we usually collide with jellyfish, suffering painful stings on our legs or arms. |
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http://www.bonus.com/contour/neuroscienceforkids/http@@/faculty.washington.edu/chudler/sting.html
(678 words)
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| | Olympus Microscopy Resource Center: Mortimer Abramowitz Gallery of Photomicrography - Jellyfish Mantle Edge |
| | The stings of some jellyfish are quite painful and can cause reactions ranging from mild rashes to paralysis or death in humans. | | | Although their bodies are composed primarily of water, jellyfish are amazingly resourceful. | | | When the movements of another creature activate the sensory hair, the nematocyst shoots from the capsule in a fraction of a second. |
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http://www.olympusmicro.com/galleries/abramowitz/pages/jellyfishedgeofmantlesmall.html
(285 words)
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| | nematocyst |
| | a structure from which a stinging fiber, called a nematocyst fiber, is discharged, such as occurs in Hydra, threadlike structure of coelenterates |
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http://www.webref.org/biology/n/nematocyst.htm
(97 words)
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| | Jellyfish -- Facts, Info, and Encyclopedia article |
| | Whenever a prey comes in contact with a tentacle, hundreds to thousands of nematocysts fire one or another type of "hook and line" into the prey's direction. | | | Impulses to these (A cell that is specialized to conduct nerve impulses) nerve cells are sent from the nerve rings that have collected information from the environment of the jellyfish through the (Click link for more info and facts about rhopalial lappet) rhopalial lappet, which is located around the animal's body. | | | Like all other cnidarians, jellyfish have stinging cells called (Click link for more info and facts about cnidocytes) cnidocytes which contains the stinging (Click link for more info and facts about nematocyst) nematocysts on their tentacles. |
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http://www.absoluteastronomy.com/encyclopedia/j/je/jellyfish.htm
(1054 words)
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| | nematocyst -- Encyclopædia Britannica |
| | Below the sail hang various structures: tentacles armed with nematocysts, or stinging cells; gonozooids, which have a reproductive function; and a single, central gastrozooid, the... | | | The capsule, which occurs on the body surface, is produced by a special cell called a cnidoblast and contains a coiled, hollow, usually barbed thread, which quickly turns outward (i.e., is everted) from the capsule upon proper stimulation. | | | Modern authorities, however, have separated the cnidarians and ctenophores on the basis of the following ctenophore characteristics: (1) the lack of the stinging cells (nematocysts) that are characteristic of cnidarians; (2) the existence of a definite mesoderm in the ctenophores; (3)... |
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http://www.britannica.com/eb/article-9055227?tocId=9055227
(587 words)
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