Stichotrich

Last updated
Stichotricha secunda Stichotricha secunda - 400x - Macronuclei (14994677881).jpg
Stichotricha secunda

The stichotrichs were a proposed group of ciliates, in the class Spirotrichea. In a classification system proposed by Eugene Small and Denis Lynn in 1985, Stichotrichia formed a subclass containing four orders: Stichotrichida, Urostylida, Sporadotrichida and Plagiotomida. [1] Although the group was made up of species traditionally classified among the "hypotrichs"—ciliates possessing compound ciliary organelles called cirri—it excluded euplotid ciliates such as Euplotes and Diophrys, which were placed in the subclass Hypotrichia. In later classifications proposed by Denis Lynn, Stichotrichia omits the order Plagiotomida (species in that group were relocated to the order Stichotrichida). [2]

Contents

In more recent classifications, members of Stichotrichia, as defined by Small and Lynn., are placed in the subclass Hypotrichia, and euplotid ciliates are placed in the subclass Euplotia. [3] [4]

Like the euplotids, stichotrichs (or hypotrichs, in the sense of Gao et al., 2016) [3] have body cilia fused into cirri, but these are mostly arranged into rows, running along the ventral surface or edges of the cell. Most stichotrichs are flattened and reasonably flexible, although some, such as Stylonychia, have rigid bodies. Characteristic genera include Stylonychia , Oxytricha , Uroleptus and Urostyla.

Etymology

Ciliate Uroleptus piscis categorized in Stichotrichia by Small and Lynn Uroleptus piscis - 160x (9836674874).jpg
Ciliate Uroleptus piscis categorized in Stichotrichia by Small and Lynn

The term stichotrich derives from the ancient greek στίχος (stíkhos), meaning "row", and θρίξ , τριχός (thríx, trikhós), meaning 'hair', [5] [6] because of the arrangement into rows of the cilia.

Genomics

The draft macronuclear genome of Oxytricha trifallax was published in 2013. [7]

Related Research Articles

<span class="mw-page-title-main">Spirotrich</span> Class of single-celled organisms

The spirotrichs are a large and diverse group of ciliate protozoa. They typically have prominent oral cilia in the form of a series of polykinetids, called the adoral zone of membranelles, beginning anterior to the oral cavity and running down to the left side of the mouth. There may also be one or two paroral membranes on its right side. The body cilia are fused to form polykinetids called cirri in some, and are sparse to absent in others.

<span class="mw-page-title-main">Alveolate</span> Superphylum of protists

The alveolates are a group of protists, considered a major clade and superphylum within Eukarya. They are currently grouped with the stramenopiles and Rhizaria among the protists with tubulocristate mitochondria into the SAR supergroup.

<span class="mw-page-title-main">Heterotrich</span> Class of single-celled organisms

The heterotrichs are a class of ciliates. They typically have a prominent adoral zone of membranelles circling the mouth, used in locomotion and feeding, and shorter cilia on the rest of the body. Many species are highly contractile, and are typically compressed or conical in form. These include some of the largest protozoa, such as Stentor and Spirostomum, as well as many brightly pigmented forms, such as certain Blepharisma.

The plagiopylids are a small order of ciliates, including a few forms common in anaerobic habitats.

<span class="mw-page-title-main">Litostomatea</span> Class of single-celled organisms

The Litostomatea are a class of ciliates. The group consists of three subclasses: Haptoria, Trichostomatia and Rhynchostomatia. Haptoria includes mostly carnivorous forms such as Didinium, a species of which preys primarily on the ciliate Paramecium. Trichostomatia (trichostomes) are mostly endosymbionts in the digestive tracts of vertebrates. These include the species Balantidium coli, which is the only ciliate parasitic in humans. The group Rhynchostomatia includes two free-living orders previously included among the Haptoria, but now known to be genetically distinct from them, the Dileptida and the Tracheliida.

<i>Paramecium</i> Genus of unicellular ciliates, commonly studied as a representative of the ciliate group

Paramecium is a genus of eukaryotic, unicellular ciliates, commonly studied as a model organism of the ciliate group. Paramecium are widespread in freshwater, brackish, and marine environments and are often abundant in stagnant basins and ponds. Because some species are readily cultivated and easily induced to conjugate and divide, they have been widely used in classrooms and laboratories to study biological processes. The usefulness of Paramecium as a model organism has caused one ciliate researcher to characterize it as the "white rat" of the phylum Ciliophora.

<span class="mw-page-title-main">Hypotrich</span> Subclass of single-celled organisms


The hypotrichs are a group of ciliated protozoa, common in fresh water, salt water, soil and moss. Hypotrichs possess compound ciliary organelles called "cirri," which are made up of thick tufts of cilia, sparsely distributed on the ventral surface of the cell. The multiple fused cilia which form a cirrus function together as a unit, enabling the organism to crawl along solid substrates such as submerged debris or sediments. Hypotrichs typically possess a large oral aperture, bordered on one side by a wreath or collar of membranelles, forming an "adoral zone of membranelles," or AZM.

<span class="mw-page-title-main">Holotricha</span> Order of single-celled organisms

Holotricha is an order of ciliates. The classification has fallen from use as a formal taxon, but the terms "holotrich" and "holotrichous" are still applied descriptively to organisms with cilia of uniform length distributed evenly over the surface of the body.

<i>Stylonychia</i> Genus of single-celled organisms

Stylonychia is a genus of ciliates, in the subclass Hypotrichia. Species of Stylonychia are very common in fresh water and soil, and may be found on filamentous algae, surface films, and among particles of sediment. Like other Hypotrichs, Stylonychia has cilia grouped into membranelles alongside the mouth and cirri over the body. It is distinguished partly by long cirri at the posterior, usually a cluster of three. The largest can just be seen at a 25x magnification, and the smallest can just be seen at a 450x magnification.

Karyorelictea is a class of ciliates in the subphylum Postciliodesmatophora. Most species are members of the microbenthos community, that is, microscopic organisms found in the marine interstitial habitat, though one genus, Loxodes, is found in freshwater.

<span class="mw-page-title-main">Ciliate</span> Taxon of protozoans with hair-like organelles called cilia

The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a different undulating pattern than flagella. Cilia occur in all members of the group and are variously used in swimming, crawling, attachment, feeding, and sensation.

<i>Euplotes</i> Genus of single-celled organisms

Euplotes is a genus of ciliates in the subclass Euplotia. Species are widely distributed in marine and freshwater environments, as well as soil and moss. Most members of the genus are free-living, but two species have been recorded as commensal organisms in the digestive tracts of sea urchins.

<i>Chilodonella uncinata</i> Species of single-celled organism

Chilodonella uncinata is a single-celled organism of the ciliate class of alveoles. As a ciliate, C. uncinata has cilia covering its body and a dual nuclear structure, the micronucleus and macronucleus. Unlike some other ciliates, C. uncinata contains millions of minichromosomes in its macronucleus while its micronucleus is estimated to contain 3 chromosomes. Childonella uncinata is the causative agent of Chilodonelloza, a disease that affects the gills and skin of fresh water fish, and may act as a facultative of mosquito larva.

<span class="mw-page-title-main">Mobilida</span> Order of protists belonging to the ciliates phylum

Mobilida is a group of parasitic or symbiotic peritrich ciliates, comprising more than 280 species. Mobilids live on or within a wide variety of aquatic organisms, including fish, amphibians, molluscs, cnidarians, flatworms and other ciliates, attaching to their host organism by means of an aboral adhesive disk. Some mobilid species are pathogens of wild or farmed fish, causing severe and economically damaging diseases such as trichodinosis.

<i>Oxytricha</i> Genus of single-celled organisms

Oxytricha is a genus of ciliates in the family Oxytrichidae.

<i>Sterkiella histriomuscorum</i> Species of single-celled organism

Sterkiella histriomuscorum, formerly Oxytricha trifallax, is a ciliate species in the genus Sterkiella, known for its highly fragmented genomes which have been used as a model for ciliate genetics.

<i>Colpidium colpoda</i> Species of protozoan

Colpidium colpoda are free-living ciliates commonly found in many freshwater environments including streams, rivers, lakes and ponds across the world. Colpidium colpoda is also frequently found inhabiting wastewater treatment plants. This species is used as an indicator of water quality and waste treatment plant performance.

<span class="mw-page-title-main">Intramacronucleata</span> Subphylum of single-celled organisms

Intramacronucleata is a subphylum of ciliates. The group is characterized by the manner in which division of the macronucleus is accomplished during binary fission of the cell. In ciliates of this subphylum, division of the macronucleus is achieved by the action of microtubules which are assembled inside the macronucleus itself. This is in contrast to heterotrich ciliates of the subphylum Postciliodesmatophora, in which division of the macronucleus relies on microtubules formed outside the macronuclear envelope.

<span class="mw-page-title-main">Armophorea</span> Class of single-celled organisms

Armophorea is a class of ciliates in the subphylum Intramacronucleata. . It was first resolved in 2004 and comprises three orders: Metopida, Clevelandellida, and Armophorida. Previously members of this class were thought to be heterotrichs because of similarities in morphology, most notably a characteristic dense arrangement of cilia surrounding their oral structures. However, the development of genetic tools and subsequent incorporation of DNA sequence information has led to major revisions in the evolutionary relationships of many protists, including ciliates. Metopids, clevelandellids, and armophorids were grouped into this class based on similarities in their small subunit rRNA sequences, making them one of two so-called "riboclasses" of ciliates, however, recent analyses suggest that Armophorida may not be related to the other two orders.

<i>Halteria</i> Genus of single-celled organisms

Halteria, sometimes referred to as the jumping oligotrich, is a genus of common planktonic ciliates that are found in many freshwater environments. Halteria are easy to locate due to their abundance and distinctive behaviour with observations of Halteria potentially dating back to the 17th century and the discovery of microorganisms. Over time more has been established about their morphology and behavior, which has led to many changes in terms of classification.

References

  1. Lee JJ (2000). The Illustrated Guide to the Protozoa Vol. I. Lawrence, Kansas: Society of Protozoologists. pp. 394–5. ISBN   1-891276-22-0.
  2. Lynn D (2008). The Ciliated Protozoa: Characterization, Classification, and Guide to the Literature (3 ed.). Springer Netherlands. ISBN   9781402082382.
  3. 1 2 Gao F, Warren A, Zhang Q, Gong J, Miao M, Sun P, et al. (April 2016). "The All-Data-Based Evolutionary Hypothesis of Ciliated Protists with a Revised Classification of the Phylum Ciliophora (Eukaryota, Alveolata)". Scientific Reports. 6: 24874. Bibcode:2016NatSR...624874G. doi:10.1038/srep24874. PMC   4850378 . PMID   27126745.
  4. Adl SM, Bass D, Lane CE, Lukeš J, Schoch CL, Smirnov A, et al. (January 2019). "Revisions to the Classification, Nomenclature, and Diversity of Eukaryotes". The Journal of Eukaryotic Microbiology. 66 (1): 4–119. doi:10.1111/jeu.12691. PMC   6492006 . PMID   30257078.
  5. Bailly A (1981-01-01). Abrégé du dictionnaire grec français. Paris: Hachette. ISBN   2010035283. OCLC   461974285.
  6. Bailly A. "Greek-french dictionary online". www.tabularium.be. Retrieved 2017-01-24.
  7. Swart EC, Bracht JR, Magrini V, Minx P, Chen X, Zhou Y, et al. (2013). "The Oxytricha trifallax macronuclear genome: a complex eukaryotic genome with 16,000 tiny chromosomes". PLOS Biology. 11 (1): e1001473. doi: 10.1371/journal.pbio.1001473 . PMC   3558436 . PMID   23382650.