Colpidium colpoda | |
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Colpidium colpoda | |
Scientific classification | |
Domain: | Eukaryota |
Clade: | Diaphoretickes |
Clade: | SAR |
Clade: | Alveolata |
Phylum: | Ciliophora |
Class: | Oligohymenophorea |
Order: | Hymenostomatida |
Family: | Tetrahymenidae |
Genus: | Colpidium |
Species: | C. colpoda |
Binomial name | |
Colpidium colpoda (Losana, 1829) Ganner & Foissner, 1989 | |
Colpidium colpoda are free-living ciliates commonly found in many freshwater environments including streams, rivers, lakes and ponds across the world. [1] 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.
The first record of Colpidium colpoda was in 1829 by Mathaeo Losana, who placed it in the genus Paramaecia. [2] It was more thoroughly described by Christian Gottfried Ehrenberg in his two volume publication Die Infusionsthierchen als vollkommene Organismen (which roughly translates to “The Infusoria as Perfect Organisms”) in 1838. The species was described in detail by Ganner and Foissner in 1989. [1]
C. colpoda is considered an intermediate sized ciliate, [3] typically between 50 and 150 μm long. The cell is roughly oval or kidney-shaped in profile, with a distinct concavity on the anterior of the oral side. Cilia are arranged in 50-63 longitudinal rows. At the center of the cell is a large, ovoid macronucleus and a small spherical micronucleus. A single contractile vacuole is located slightly posterior to the middle of the body, near the right side. [4]
Like many ciliates, it is a heterotrophic bacterivore that ingests bacteria through an oral groove. C. colpoda reproduces asexually every 4–6 hours, [5] with variation in division rates arising from environmental conditions and the identity of the available bacterial food source. [6]
In general, it is believed that ciliates form a monophyletic group that diverged from other eukaryotes early in evolutionary history, following the evolution of heterokaryotic genetic systems but prior to the evolution of multicellularity and some organelles such as endoplasmic reticulum and Golgi complex. [7] Colpidium falls within the ciliate taxonomic order Hymenostomatida, which also includes the well-studied Tetrahymena and Glaucoma genera. Previous work suggests that Colpidium seems to be more closely related to Glaucoma than to Tetrahymena. [8] However, more recent analyses have found the opposite – that Colpidium is, in fact, more closely related to Tetrahymena than to Glaucoma. [9]
Although a complete genome is not available for Colpidium colpoda, partial sequences have been published for the small subunit 18S rRNA gene and the cytochrome oxidase subunit 1 (cox1) gene [10] and complete sequences for the telomerase RNA gene [11] and the 5.8S rRNA gene. [12] Within the same taxonomic family as C. colpoda is the microbial model organism Tetrahymena thermophila. There is a large body of scientific literature on the T. thermophila genome as a representative of the Alveolates, a major evolutionary branch of eukaryotes that includes all ciliates, dinoflagellates and apicomplexans. [13] Like many ciliates, T. thermophila has a surprisingly complex genome that consists of a germline micronucleus and a somatic macronucleus that function and replicate independently of one another. In 2006, the full genome of the T. thermophila macronucleus was sequenced [14]
Because Colpidium colpoda feeds on bacteria, this species is typically found in heavily polluted freshwater habitats. For this reason, presence of C. colpoda is often seen as an indicator of poor water quality. [15] C. colpoda and its congeners are also commonly used in laboratory microcosm experiments. [16] Colpidium colpoda can be used to accelerate the rate of degradation of crude oil during bioremediation, [17] although the exact mechanism behind this relationship is unclear. Speculation points toward secretion of mucus that acts as an emulsifier, mechanical action of cilia contributing to emulsification and reduction of competition between bacteria that contribute to hydrocarbon degradation and those that do not through grazing, amongst other possibilities.
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.
Tetrahymena, a unicellular eukaryote, is a genus of free-living ciliates. The genus Tetrahymena is the most widely studied member of its phylum. It can produce, store and react with different types of hormones. Tetrahymena cells can recognize both related and hostile cells.
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.
A unicellular organism, also known as a single-celled organism, is an organism that consists of a single cell, unlike a multicellular organism that consists of multiple cells. Organisms fall into two general categories: prokaryotic organisms and eukaryotic organisms. Most prokaryotes are unicellular and are classified into bacteria and archaea. Many eukaryotes are multicellular, but some are unicellular such as protozoa, unicellular algae, and unicellular fungi. Unicellular organisms are thought to be the oldest form of life, with early protocells possibly emerging 3.8–4.8 billion years ago.
Stentor, sometimes called trumpet animalcules, are a genus of filter-feeding, heterotrophic ciliates, representative of the heterotrichs. They are usually horn-shaped, and reach lengths of two millimeters; as such, they are among the largest known extant unicellular organisms. They reproduce asexually through binary fission.
Nuclear dimorphism is a term referred to the special characteristic of having two different kinds of nuclei in a cell. There are many differences between the types of nuclei. This feature is observed in protozoan ciliates, like Tetrahymena, and some foraminifera. Ciliates contain two nucleus types: a macronucleus that is primarily used to control metabolism, and a micronucleus which performs reproductive functions and generates the macronucleus. The compositions of the nuclear pore complexes help determine the properties of the macronucleus and micronucleus. Nuclear dimorphism is subject to complex epigenetic controls. Nuclear dimorphism is continuously being studied to understand exactly how the mechanism works and how it is beneficial to cells. Learning about nuclear dimorphism is beneficial to understanding old eukaryotic mechanisms that have been preserved within these unicellular organisms but did not evolve into multicellular eukaryotes.
Didinium is a genus of unicellular ciliates with at least ten accepted species. All are free-living carnivores. Most are found in fresh and brackish water, but three marine species are known. Their diet consists largely of Paramecium, although they will also attack and consume other ciliates. Some species, such as D. gargantua, also feeds on non-ciliate protists, including dinoflagellates, cryptomonads, and green algae.
Ribosomal particles are denoted according to their sedimentation coefficients in Svedberg units. The 60S subunit is the large subunit of eukaryotic 80S ribosomes, with the other major component being the eukaryotic small ribosomal subunit (40S). It is structurally and functionally related to the 50S subunit of 70S prokaryotic ribosomes. However, the 60S subunit is much larger than the prokaryotic 50S subunit and contains many additional protein segments, as well as ribosomal RNA expansion segments.
The eukaryotic small ribosomal subunit (40S) is the smaller subunit of the eukaryotic 80S ribosomes, with the other major component being the large ribosomal subunit (60S). The "40S" and "60S" names originate from the convention that ribosomal particles are denoted according to their sedimentation coefficients in Svedberg units. It is structurally and functionally related to the 30S subunit of 70S prokaryotic ribosomes. However, the 40S subunit is much larger than the prokaryotic 30S subunit and contains many additional protein segments, as well as rRNA expansion segments.
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.
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.
Halofolliculina corallasia is a species of heterotrich ciliates identified as a cause of the syndrome called skeletal eroding band (SEB). It is the first coral disease pathogen that is a protozoan as well as the first known to be a eukaryote; all others identified are bacteria. Like other members of the folliculinid family, H. corallasia is sessile and lives in a "house" called a lorica, into which the cell can retreat when disturbed. The mouth is flanked by a pair of wing-like projections that are fringed with polykinetids, groups of cilia that work in groups to produce a current that draws food into the "mouth".
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.
Frontonia is a genus of free-living unicellular ciliate protists, belonging to the order Peniculida. As Peniculids, the Frontonia are closely related to members of the genus Paramecium. However, whereas Paramecia are mainly bacterivores, Frontonia are capable of ingesting large prey such as diatoms, filamentous algae, testate amoebas, and even, in some circumstances, members of their own species. In bacteria-rich saprobic conditions, Frontonia leucas can live as a facultative bacterivore.
Climacostomum is a genus of unicellular ciliates, belonging to the class Heterotrichea.
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.
Colpoda inflata is a unicellular organism, belonging to the genus Colpoda. Colpodeans are eucaryotic protozoans, that mainly feed on bacteria (bacteriophagous), vary a lot in size and have a funnel-shaped vestibule.
Condylostoma is a genus of unicellular ciliate protists, belonging to the class Heterotrichea.
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.
Tetrahymena thermophila is a species of Ciliophora in the family Tetrahymenidae. It is a free living protozoa and occurs in fresh water.
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