nostoc

nostoc
/nos"tok/, n.
any freshwater, blue-green alga of the genus Nostoc, often occurring in jellylike colonies in moist places.
[1640-50; < NL, coined by Paracelsus]

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Any of the cyanobacteria that make up the genus Nostoc.

The cells are arranged in beadlike chains grouped together in a gelatinous mass. Ranging from microscopic to walnut-sized, nostoc masses may be found on soil and floating in still water. A special thick-walled cell has the ability to withstand drying for long periods of time. After 70 years of dry storage, cells of one species can germinate into filaments when moistened. Like most other cyanobacteria, nostocs contain two pigments and are capable of nitrogen fixation.

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algae
      genus of blue-green algae with cells arranged in beadlike chains that are grouped together in a gelatinous mass. Ranging from microscopic to walnut-sized, masses of Nostoc may be found on soil and floating in quiet water. Reproduction is by fragmentation. A special thick-walled cell (akinete) has the ability to withstand desiccation for long periods of time. After 70 years of dry storage, the akinete of one species germinates into a filament when moistened. Like most blue-green algae, Nostoc contains two pigments, blue phycocyanin and red phycoerythrin, as well as chlorophyll, and has the ability to fix nitrogen in specialized cells called heterocysts. A terrestrial species has been used as a supplementary food source in Asia.

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Universalium. 2010.

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  • nostoc — [ nɔstɔk ] n. m. • XVIIe nostoch; o. i., mot créé par Paracelse ♦ Bot. Algue bleue microscopique (cyanobactéries) qui forme des masses gélatineuses dans les sols humides. ● nostoc nom masculin Algue (cyanophycée) des sols humides et des eaux… …   Encyclopédie Universelle

  • Nostoc — Nos toc, prop. n. [F.] (Bot.) A genus of alg[ae]. The plants are composed of moniliform cells imbedded in a gelatinous substance. [1913 Webster] Note: {Nostoc commune} is found on the ground, and is ordinarily not seen; but after a rain it swells …   The Collaborative International Dictionary of English

  • nostoc — NOSTÓC s. m. algă albastră microscopică, din solurile umede. (< fr. nostoc) Trimis de raduborza, 15.09.2007. Sursa: MDN …   Dicționar Român

  • nostoc — [näs′täk΄] n. [ModL, coined by PARACELSUS Philippus Aureolus] any of a genus (Nostoc) of blue green algae, having twisted, coiled filaments embedded in a gelatinous material and forming spherical colonies …   English World dictionary

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  • Nostoc — Vauch. (Nostok, Schleimling, Zittertang, Zitteralge), Algengattung aus der Familie der Nostokazeen, blaugrüne Algen, deren kugelrunde Zellen in einer homogenen Schleimmasse rosenkranzartige Fäden bilden, in denen in bestimmten Abständen einzelne… …   Meyers Großes Konversations-Lexikon

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  • Nostoc — Crachat de lune Nostoc pr …   Wikipédia en Français

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