color = khaki
name = Peritrichs
domain = Eukaryota
unranked_phylum = Alveolata
phylum = Ciliophora
classis = Oligohymenophorea
subclassis = Peritrichia
subclassis_authority = Stein 1859
subdivision_ranks = Typical orders
subdivision =
The peritrichs are a large and distinctive group of ciliate protozoa. They are usually bell or disc shaped, with a prominent paroral membrane arising from the oral cavity and circling counter-clockwise around the anterior of the cell, accompanied by a smaller series of membranelles. The oral cavity is apical and funnel shaped, with a contractile vacuole discharging directly into it. When disturbed, the anterior of the cell can contract. The rest of the body is unciliated, except for a "telotroch band" circling the posterior in mobile species and stages.

The larger order of peritrichs are the Sessilida. Most of these have modified posterior kinetosomes which secrete a contractile stalk. The unattached stage, called a "telotroch", is mouthless. These are common in both freshwater and marine environments, and many live attached to aquatic plants and animals. They are either solitary or produce branched colonies. A few secrete a lorica. "Vorticella" is one of the best-known genera. Stalks may be as long as 2 mm, and in some cases where they are highly contractile can be extended up to 3 mm.

The other peritrichs make up the order Mobilida. In these the posterior of the cell is enlarged and modified to form a complex holdfast, allowing the cell to temporarily attach to some host organism. Most live on the integument or gills of freshwater and marine invertebrates, but other hosts occur, including fish and even other ciliates, and other locations as well. Some can be pathenogenic in high populations.

The peritrichs were first defined by Friedrich von Stein in 1859. Initially they were considered spirotrichs, then treated as a separate category, before receiving their modern placement.

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Look at other dictionaries:

  • peritrich — ⇒ Bakteriengeißel …   Deutsch wörterbuch der biologie

  • Peritrich — Flagellen oder Geißeln (lat. flagellum Geißel) sind lange, dünne Gebilde bei Lebewesen, die von der Zelloberfläche abstehen und der Bewegung dienen. Sie sind bei Prokaryoten und bei Eukaryoten hinsichtlich Struktur und Funktionsweise… …   Deutsch Wikipedia

  • peritrich — per·i·trich (pĕrʹĭ trĭk ) n. pl. pe·rit·richs, also pe·rit·ri·cha (pə rĭtʹrĭ kə) Any of various protozoans, such as the vorticella, having a wide oral opening surrounded by cilia.   [From New Latin Peritrichida, former order name : peri + Greek… …   Universalium

  • peritrich — noun A ciliate protozoan of the subclass Peritrichia. See Also: spirotrich …   Wiktionary

  • peritrich — pe|ri|trich <Adj.> [zu griech. perí = um herum u. thríx (Gen.: trichós) = Haar] (Med., Biol.): (von Mikroorganismen) auf der ganzen Oberfläche mit Geißeln (2) besetzt …   Universal-Lexikon

  • peritrich — peri·trich per ə .trik n any ciliate of the order Peritricha * * * peri·trich (perґĭ trik) 1. any ciliate protozoan of the subclass Peritrichia. 2. peritrichous …   Medical dictionary

  • peritrich — pe|ri|trich auch: pe|rit|rich 〈Adj.; bei Mikroorganismen〉 auf der Oberfläche mit Geißeln umgeben [Etym.: <peri… + grch. thrix, Gen. trichos »Haar«] …   Lexikalische Deutsches Wörterbuch

  • peritrich — peri|tri̱ch [zu ↑peri... u. gr. ϑριξ, Gen.: τριχος = Haar]: allseitig mit Geißeln versehen (von Mikroorganismen, z. B. Typhusbakterien) …   Das Wörterbuch medizinischer Fachausdrücke

  • peritrich — pe|ri|trich* <zu ↑peri... u. gr. thríx, Gen. trichós »Haar«> auf der ganzen Oberfläche mit Geißeln besetzt (von Mikroorganismen, z. B. Typhusbakterien; Med., Biol.) …   Das große Fremdwörterbuch

  • peritrich — peri·trich …   English syllables

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