| Colpoda | |
|---|---|
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| Colpoda inflata | |
Scientific classification  | |
| Domain: | Eukaryota |
| Clade: | Diaphoretickes |
| Clade: | SAR |
| Clade: | Alveolata |
| Phylum: | Ciliophora |
| Class: | Colpodea |
| Order: | Colpodida |
| Family: | Colpodidae |
| Genus: | Colpoda O. F. Müller, 1773 |
| Species [1] | |
| |
Colpoda is a genus of ciliates in the class Colpodea, order Colpodida, and family Colpodidae. [2]
Colpoda are distinctly reniform (kidney-shaped) and are strongly convex on one side, and concave on the other. The concave side often looks like a bite was taken out of it. Although they are not as well known as the paramecium, they are often the first protozoa to appear in hay infusions, especially when the sample does not come from an existing mature source of standing water.
Colpoda are often found in moist soil and because of their ability to readily enter protective cysts will quite frequently be found in desiccated samples of soil and vegetation [3] as well as in temporary natural pools such as tree holes. [4] They have also been found in the intestines of various animals, and can be cultured from their droppings. [5]
Colpoda cucullus has been found inhabiting the surface of plants and seems to dominate the microfauna there. Several species of Colpoda have been found in the pitcher plant Sarracenia purpurea , despite the presence of protease digestive enzymes in the liquid. [6]
Colpoda also tends to be found in abundance where increased levels of bacteria offer an enriched food source. In commercial chicken houses, for example, they seemed to be ubiquitous but the species found vary widely from one location to the next, suggesting that these populations represent local soil and aquatic populations which migrated into the new habitat. [7]
In addition to inhabiting a wide variety of microclimates, Colpoda can be found almost everywhere around the world where there is standing water or moist soil, even where these conditions are only ephemeral. Colpoda brasiliensis for example was discovered in Brazilian floodplains in 2003. [8] Colpoda irregularis has been found in the high desert region of Southwest Idaho. Colpoda aspera has been found in the Antarctic. Colpoda are also found in the arctic where warmer temperatures and longer summers lead to greater density and species diversity. [9]
Not only is the genus widespread, but there are also several species that have nearly global distribution, and, indeed, it has been suggested this may be true of all species, a fact that could be borne out by better investigation. [10] Though Colpoda are not normally found in the marine environment, there are many ways they can travel from one continent to another. For example, cysts can become lodged in the plumage of migratory birds, becoming dislodged hundreds or even thousands of miles away. Also, because cysts are so small and light, they can be swept by air currents into the upper atmosphere, and then come down on another continent. [11]
Colpoda normally divides into cysts, from which two to eight individuals emerge, four being the most common number. This produces genetically identical individuals. The rate at which such reproduction occurs and how it is affected by various environmental conditions has been the subject of a great deal of scientific research. [12]
On rare occasions, Colpoda have been observed to divide into 4 individuals without producing a cyst wall. It has been suggested that cyst less reproduction was the normal mode of reproduction for Colpoda under optimum conditions and that the formation of cysts was a reaction to adverse environmental conditions. However, the knowledge gained by many years of culturing Colpoda in hay infusions has shown that this mode of reproduction remains rare despite what would seem to be ideal environmental conditions. [13]
As in other ciliates, division in Colpoda may be preceded by a sexual phenomenon known as conjugation. This involves two Colpoda joining at the oral groove and exchanging DNA. Following conjugation, the Colpoda divides, redistributing the DNA of the two original cells to produce numerous genetically distinct offspring. [14] [15] [16]
Most Colpoda species are either primarily or exclusively bacterivores feeding on a wide variety of bacteria, which include Moraxella . Several scientific studies have been made on the effect of different bacterial diets on the rate of Colpoda reproduction. Much has been written on the ecological role that Colpoda fulfill in the soil. [17]
In addition to their role as predators of bacteria, Colpoda are themselves prey to a large variety of species. This includes other protozoans as well as small animals such as mosquito larva, [18] other insect larva, and waterfleas. [19]
In addition to their use in education and in a wide variety of scientific studies, Colpoda have at times been suggested for more practical uses. Colpoda steini has been suggested as a means to assess the toxicity of soil treated with sewage sludge [20] and as a means to detect chemical contamination in general, possibly in the wake of a terrorist attack. [21]
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The opalines are a small group of peculiar heterokonts, currently assigned to the family Opalinidae, in the order Slopalinida. Their name is derived from the opalescent appearance of these microscopic organisms when illuminated with full sunlight. Most opalines live in the large intestine and cloaca of anurans, though they are sometimes found in fish, reptiles, molluscs and insects; whether they are parasitic is not certain. The unusual features of the opalines, first observed by Antonie van Leeuwenhoek in 1683, has led to much debate regarding their phylogenetic position among the protists.
Blepharisma is a genus of unicellular ciliate protists found in fresh and salt water. The group includes about 40 accepted species, and many sub-varieties and strains. While species vary considerably in size and shape, most are easily identified by their red or pinkish color, which is caused by granules of the pigment blepharismin.
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.
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.
Protozoa are a polyphyletic group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic debris. Historically, protozoans were regarded as "one-celled animals".
Plagiopyla is a genus of ciliates. It includes nine species:
Nassula is a genus of unicellular ciliates, belonging to the class Nassophorea. Like other members of the class, Nassula possesses a basket-like feeding apparatus made up of cytopharyngeal rods (nematodesmata), which are themselves composed of closely packed microtubules. Nassula use this structure to ingest filamentous cyanobacteria, drawing individual strands of blue-green algae through the cytopharynx and into the body of the cell, where they are digested. As the algae are broken down, they can take on a variety of bright colours, which give Nassula a distinctive, variegated appearance under the microscope.
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.
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.
Dileptus is a genus of unicellular ciliates in the class Litostomatea. Species of Dileptus occur in fresh and salt water, as well as mosses and soils. Most are aggressive predators equipped with long, mobile proboscides lined with toxic extrusomes, with which they stun smaller organisms before consuming them. Thirteen species and subspecies of Dileptus are currently recognized.
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.
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.
Loxodidae is a family of karyorelict ciliates.
Wilbertomorphidae is a family of karyorelictean ciliates. The family is monotypic, because it contains a single genus Wilbertomorpha with a single known species, Wilbertomorpha colpoda.
Tracheloraphis is a genus of ciliates in the family Trachelocercidae.
Stentor roeselii is a free-living ciliate species of the genus Stentor, in the class Heterotrichea. It is a common and widespread protozoan, found throughout the world in freshwater ponds, lakes, rivers and ditches.
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.
Trachelocercidae is a family of ciliates in the class Karyorelictea.
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