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Topic: Nematocyst

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	Nematocyst
		Nematocyst is an active countermeasure for the spamforo trojan.
		Spamforo makes the infected machines send piles of spam; nematocyst emulates an infected machine, but doesn't send any spam; the intent is to make the trojan network useless by loading it with fake slaveclients.
		Nematocyst is written in perl and has been tested on Debian GNU/Linux.
	deekoo.net /technocracy/nematocyst (114 words)

	Cnidocyte - Wikipedia, the free encyclopedia
		Nematocysts are composed of a coiled thread-like structure attached to the bulb-shaped nematocyst capsule body.
		The nematocyst capsule stores a large concentration of calcium ions, which are released from the capsule into the cytoplasm of the cnidocyte when the trigger is activated.
		Nematocyst discharge is one of the fastest biological processes and takes not more than few microseconds.
	en.wikipedia.org /wiki/Nematocyst (442 words)

	EM PROJECT: CHARLES MOFFET
		The nematocyst of the adjacent is torn from the section due to mineralization by calcium.
		Discharged nematocyst lodged in the cuticle of Artemia prey.
		The initial template for the development of the nematocyst capsule wall is thought to be from vesicles derived from the trans-cisternal face of the Golgi Apparatus (Watson 1988).
	www.csulb.edu /~zedmason/emprojects/charlie/moffet.html (1141 words)

	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.
		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.
		Nematocysts are usually most abundant on the feeding tentacles of all species, and within the digestive cavity of some species.
	www.users.totalise.co.uk /~darrenbarton/id93.htm (212 words)

	Things with Stings… by Ronald L. Shimek, Ph.D. - Reefkeeping.com
		Nematocysts are invisible to the unaided eye, but are found by the millions in large cnidarians.
		Both the nematocyst of the coral and the tooth of the snail are adapted to sting their prey.
		Nematocyst discharge and surface of the ordinary and sweeper tentacles of a scleractinian coral, Galaxea fascicularis.
	www.reefkeeping.com /issues/2002-07/rs/index.htm (4721 words)

	eMJA: Pereira et al, Pressure immobilisation bandages in first-aid treatment of jellyfish envenomation: current ...
		nematocysts were viewed under direct microscopy before and after applying 40 mmHg pressure (replicating the pressure of PIB); and saline washings of discharged nematocysts before and after applying pressure were tested for toxicity (time to ventricular standstill after injecting into live prawns).
		After removal of the tentacles, the membrane was inverted, leaving the nematocyst bodies lying within the cylinder and their penetrating shafts directed externally through the membrane.
		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.
	www.mja.com.au /public/issues/173_11_041200/pereira/pereira.html (1668 words)

	Biochemistry of the Nematocyst
		Nematocysts are exclusive to Cnidarians, and enable them to capture prey, defend their territory (as seen in corals and their mesenterial filaments), and defend themselves from predation.
		These distinct types of nematocysts fall under four functional categories: those that pierce prey or predator and inject them with toxin, those that ensnare prey, those that adhere to prey or a substrate, and those that are used specifically for defense.
		The representative nematocyst, whose characteristics are shared amongst all these different morphological and functional nematocysts, is produced by the nematocyte (as specialized cell type) from a post-Golgi vesicle (Ozbeck et al., 2002).
	www.studentsasteachers.com /website/Cnidarian%20Defense/Biochemistry%20of%20the%20Nematocyst.htm (788 words)

	Cnidocyte (Site not responding. Last check: 2007-10-03)
		are composed of a coiled thread-like structure to the bulb-shaped nematocyst capsule body.
		Nematocyst is one of the fastest processes in and takes not more than few microsconds.
		Some nematocysts puncture the skin or exoskeleton of an organism and inject a toxin.
	www.freeglossary.com /Penetant_nematocyst (147 words)

	Cnidocytes (Site not responding. Last check: 2007-10-03)
		Nematocysts are composed ofa coiled thread-like structure attached to the bulb-shaped nematocyst capsule body.
		Nematocyst discharge is oneof the fastest processes in biology and takes not more than few microsconds.
		Some nematocysts puncture the skin or exoskeleton of an organism andinject a paralyzing toxin.
	www.therfcc.org /cnidocytes-157737.html (171 words)

	The Anemones, Corals and Jellyfish (Phylum Cnidaria)
		Nematocysts, and their enclosing Cnidocysts come in about 24 different forms, the differences play a functional role in the classification of the phylum.
		The fundamental nematocyst is a thin tubular thread with barbs at the far end, though there may be barbs near the base as well.
		When the nematocyst is discharged, the barbs penetrate the skin of the prey and a toxin can be injected.
	www.earthlife.net /inverts/cnidaria.html (1238 words)

	The Biological Bulletin: Response in nematocyst uptake by the nudibranch Flabellina verrucosa to the presence of ... (Site not responding. Last check: 2007-10-03)
		Response in nematocyst uptake by the nudibranch Flabellina verrucosa to the presence of various predators in the Southern Gulf of Maine.
		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.
		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...
	highbeam.com /library/doc0.asp?docid=1G1:112022366&refid=ink_tptd_mag (205 words)

	EM PROJECT: MICHELLE JOHNSON AND MISTY BORJA
		Nematocysts are intracellular structures that contain harpoon-like devices that can be everted rapidly into the predator upon appropriate stimulation (Behrens, 1980).
		During the digestion process, the nematocysts of the prey remain undischarged and are transported via an undetermined mechanism through interconnecting tubules from the digestive diverticula into a sac like structure at the tip of the cerata called the cnidosac.
		Intact nematocysts were observed within these cells in light micrographs, and, although the structures were removed during thin sectioning, a peri-nematocyst membrane could be observed delineating the nematocyst implying that it was of extracellular origin and had been internalized, presumably by a process such as phagocytosis.
	www.csulb.edu /~zedmason/emprojects/misty/nudibr.html (1810 words)

	World Intellectual Property Organization (Site not responding. Last check: 2007-10-03)
		This invention provides a method of inhibiting nematocyst or polar capsule discharge comprising applying an effective amount of the composition comprising formalin and chloride to the skin of a subject prior to contact with nematocysts or polar capsules, thereby inhibiting nematocyst or polar capsule discharge.
		The average number of nematocysts that were counted on a skin sample that was treated with the ointment base alone was 27+/-10 nematocysts.
		A method of inhibiting nematocyst or polar capsule discharge comprising applying an effective amount of the composition of Claims 1-25, to the skin of a subject prior to contact with nematocysts or polar capsules, thereby inhibiting nematocyst or polar capsule discharge.
	www.wipo.int /ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=01/37778.010531&ELEMENT_SET=DECL (4793 words)

	AHG4_e
		Nematocyst discharge is initiated by voltage- and Ca -dependent exocytosis (Gitter et al., 1994), which is triggered by mechanoreception that can be blocked by streptomycin (Gitter and Thurm, 1993a).
		Revisiting the history of the recognition of cnidarians as animals and the discovery of nematocysts, 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 nematocyst is an organelle of the nematocyte, which developes from the (immature) nematoblast.
	www.medizin.fu-berlin.de /klinphys/themen_ahg/ahg4_nematocysts_e.htm (1061 words)

	Phylum Cnidaria
		Nematocysts are the specialized organelle that is actually "fired" within a cnidocyte and it is created by the golgi bodies within interstitial cells.
		As cells divide, intercellular bridges remain and nematocyst development is synchronized because the cells are not completely divided, they occur in groups of 16.
		Nematocysts are among the most complex intracellular structures in the animal kingdom.
	comenius.susqu.edu /bi/322/IZLecture9.htm (1558 words)

	NEMATOCYST (Site not responding. Last check: 2007-10-03)
		According to the American Heritage dictionary, nematocyst is a capsule within specialized cells of certain cnidarians (coelenterates) such as jellyfish, containing a barbed thread-like tube that delivers a paralyzing sting when propelled into attackers and prey.
		Nematocyst is one of the unique characteristics of the phylum Cnidaria.
		Nematocyst is also used for defense, anchoring and sometimes locomotion.
	www.cc.u-ryukyu.ac.jp /~coral/Action/NEMATOCYST.htm (250 words)

	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.
		Thus the barb or coiled thread that is inside the nematocyst as it lies in the cnidoblast becomes the tip and comes into contact with its prey.
		As they brush by the tentacles of the polyps, they trigger the explosion of the cnidnocysts that extrude the long, hollow, microscopic threads (nematocysts), which unravel in a burst, penetrating or sticking to the planktonic organism and capturing or paralysing it.
	www.scsoft.de /et/et2.nsf/KAP3View/2BCB3D6F97D7B531C125645A00008612 (474 words)

	Poly-{gamma}-glutamate synthesis during formation of nematocyst capsules in Hydra -- Szczepanek et al. 115 (4): 745 -- ...
		Poly-{gamma}-glutamate synthesis during formation of nematocyst capsules in Hydra -- Szczepanek et al.
		Nematocysts are explosive organelles found in all Cnidaria.
		AO staining of nematocysts after fixation in the presence and absence of chelators of divalent ions.
	jcs.biologists.org /cgi/content/full/115/4/745 (3522 words)

	other cnidaria
		A nematocyst is a bulbous double-walled structure containing a spirally folded, venom-filled tread with a minute barb at it's tip.
		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.
		In spawning either males release sperm that swims to the female for internal fertilisation and produce a swimming larvae for long distance dispersal or both males and females release their gametes (sperm and eggs) into the water for external fertilization.
	www.reefpix.com.au /guidecnidaria.html (635 words)

	nematocyst -- Encyclopædia Britannica
		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.
		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...
		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)...
	www.britannica.com /eb/article-9055227?tocId=9055227 (587 words)

	Wonders of the Seas: Cnidarians (Site not responding. Last check: 2007-10-03)
		When the nematocyst is called upon to fire, the thread is uncoiled, and springs straight.
		The nematocyst is fired either by the tentacle touching something, 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.
	www.oceanicresearch.org /cnidarian.html (679 words)

	Nikon MicroscopyU Movie Gallery: Hydra (Coelenterata) Video No. 5
		However, they do have nematocysts, or cnidae, the microscopic intracellular stinging capsules characteristic of this phylum and for which it is named.
		Hydras have four types of nematocysts on their tentacles, which are used for a variety of purposes.
		The largest nematocyst has barbs that anchor the prey to the tentacle from which it was fired.
	www.microscopyu.com /moviegallery/pondscum/coelenterata/hydra/t1/hydra05.html (248 words)

	xm2.html (Site not responding. Last check: 2007-10-03)
		Pressure inside nematocysts has been measured to be as high as 150 atmospheres.
		Also within the nematocysts is a high concentration of Ca and Mg This implies a very tight structure within a nematocyst, not high pressure.
		Pollack mentions nematocysts because they represent an example of extremely rapid "secretion" and expansion, and they support his case that there's more to secretion than simple diffusion.
	www.cwu.edu /~verheys/320w02/xm2key.html (1703 words)

	Cnidarian Characters (Site not responding. Last check: 2007-10-03)
		Structures seen in the development of the so-called "polar capsule" of Thelohanellus nikolskii labeled in accordance with the homologous structure in cnidarian nematocysts.
		Figures A through D represent the earliest stage in cellular ontogeny through to that of the mature nematocyst respectively.
		None of the figures or data presented here can be reproduced without the consent of the authors or of the Journal of Parasitology.
	research.amnh.org /~siddall/myxozoa/cnid_char.html (158 words)

	eMedicine - Jellyfish Stings : Article Excerpt by: David Cheng, MD (Site not responding. Last check: 2007-10-03)
		This architectural arrangement of warts, ridges, spirals, and terminal swelling may be reflected in the skin pattern left via the sting and helps identify the species involved in the envenomation.
		While the amount of toxin expressed by a single nematocyst is minute, several thousand nematocysts discharging at once have a significant effect.
		Functionally, the toxin causes sodium and calcium ion transport abnormalities, disrupts cellular membranes, releases inflammatory mediators, and acts as a direct toxin on the myocardium, nervous tissue, hepatic tissue, and kidneys.
	www.emedicine.com /derm/byname/jellyfish-stings.htm (570 words)

	A switch in disulfide linkage during minicollagen assembly in Hydra nematocysts
		At the apex of the cyst (arrow), minicollagen-filled vesicular structures are observed.
		Figure 9 Schematic drawing of minicollagen and H22 antigen distribution during nematocyst morphogenesis.
		Minicollagen is shown in red, the outer wall antigen H22 in green and membranes are drawn as blue lines.
	www.nature.com /emboj/journal/v20/n12/fig_tab/7593804ft.html (1142 words)

	Novel Role of Calcium in Exocytosis: Mechanism of Nematocyst Discharge as Shown by X-Ray Microanalysis -- Lubbock et ...
		Mature nematocysts of the sea anemones Rhodactis rhodostoma and Anthopleura elegantissima contain a fluid that has a high concentration of solutes and is extraordinarily rich in calcium (ca.
		The undischarged capsule is surrounded by a membrane that probably acts as a selective permeability barrier between the cytoplasm and the nematocyst fluid.
		During discharge the nematocyst moves to the surface of the nematocyte and comes into contact with the external sea water medium.
	www.pnas.org /cgi/content/abstract/78/6/3624 (257 words)

	Getting Nailed by Jellies - Undercurrent, September 2003 (Site not responding. Last check: 2007-10-03)
		A nematocyst typically fires as the result of friction, such as brushing up against fire coral or stinging hydroids, bumping into a jellyfish, or getting thimble jelly larvae between you and your suit.
		It is designed to keep nematocysts from being activated and has both research and anecdotal reports of effectiveness.
		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).
	www.undercurrent.org /UCnow/articles/Jellies200309.shtml (1166 words)

	Capitata
		Medusae with or without exumbrellar nematocyst tracks, bell margin oblique or straight, radial radial canals; mouth usually circular; gonads covering manubrium entirely; one to four marginal tentacles; with or without asexual medusae budding from marginal bulbs; ocelli absent.
		Medusa umbrella evenly rounded; four perradial exumbrellar nematocyst pads, pads either oval, clavate, elongate or linear, usually containing stenoteles; manubrium cylindric, mouth simple, circular; gonads usually interradial, rarely in a single mass around manubrium; four radial canals; marginal tentacles 0, 2 or 4, hollow, each with numerous abaxial stalked cnidophores containing macrobasic euryteles; without ocelli.
		Medusa free swimming eumedusoids with exumbrellar nematocyst patches, radial and circular canals present, without tentacles and sense organs; gonads occupying the place of an indistinct manubrium.
	www.ville-ge.ch /musinfo/mhng/hydrozoa/antho/capitata.htm (1113 words)

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