trichocyst

trichocyst
—trichocystic, adj.
/trik"euh sist'/, n. Zool.
an organ of offense and defense embedded in the outer cytoplasm of certain protozoans, consisting of a small elongated sac containing a fine, hairlike filament capable of being ejected.
[1850-55; TRICHO- + CYST]

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 a structure in the cortex of certain ciliate and flagellate protozoans consisting of a cavity and long, thin threads that can be ejected in response to certain stimuli. Trichocysts may be widely distributed over an organism or restricted to certain areas (e.g., tentacles, papillae, around the mouth). There are several types. Mucoid trichocysts are elongated inclusions that may be ejected as visible bodies after artificial stimulation. Filamentous trichocysts in Paramecium and other ciliates are discharged as filaments composed of a cross-striated shaft and a tip. Toxicysts (in Dileptus and certain other carnivorous protozoans) tend to be localized around the mouth. When discharged, a toxicyst expels a long, nonstriated filament with a rodlike tip, which paralyzes or kills other microorganisms; this filament is used to capture food and, presumably, in defense.

      The functional significance of other trichocysts is uncertain, although those of Paramecium apparently can be extruded for anchorage during feeding.

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Universalium. 2010.

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Look at other dictionaries:

  • Trichocyst — Trich o*cyst, n. [Gr. tri x, tricho s, a hair + ? bag.] (Zo[ o]l.) A lasso cell. [1913 Webster] …   The Collaborative International Dictionary of English

  • trichocyst — [trik′ə sist΄] n. [ TRICHO + CYST] any of the many tiny, rodlike, stinging and attachment organelles embedded in the ectoplasm of many ciliated protozoans trichocystic [trik′ōsis′tik] adj …   English World dictionary

  • Trichocyst — A trichocyst is a structure in the cortex of certain ciliate and flagellate protozoans consisting of a cavity and long, thin threads that can be ejected in response to certain stimuli. Trichocysts may be widely distributed over an organism or… …   Wikipedia

  • trichocyst — Small membrane bounded vesicle lying below the pellicle of many ciliates. Fusion of the trichocyst with the plasma membrane occurs at a predictable site which can therefore be examined for membrane specialization …   Dictionary of molecular biology

  • trichocyst — noun Date: 1859 any of the minute lassoing or stinging organelles of protozoans and especially of many ciliates …   New Collegiate Dictionary

  • trichocyst — noun A threadlike organ in certain protozoans that can be discharged suddenly in order to grasp or sting …   Wiktionary

  • trichocyst — One of a number of structures, in the form of minute elongated cysts, arranged radially around the periphery of a protozoan cell and containing fluid which when discharged serves for offense or defense; found in ciliates, such as Paramecium… …   Medical dictionary

  • trichocyst — n. organ in the protoplasm of some single celled organisms which can eject a filament for purposes of offense or defense …   English contemporary dictionary

  • trichocyst — n. (Zool.) Lasso cell …   New dictionary of synonyms

  • trichocyst — trich·o·cyst …   English syllables

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