''Colpoda'' is a genus of

ciliate The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to flagellum, eukaryotic flagella, but are in general shorter and present in much larger numbers, with a ...

s in the class

Colpodea The Colpodea are a class of ciliates, of about 200 species common in freshwater and soil habitats. The body cilia are typically uniform, and are supported by dikinetids of characteristic structure, with cilia on both kinetosomes. The mouth may ...

, order Colpodida, and family Colpodidae.

Description

''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 ''Paramecium'' ( , , plural "paramecia" only when used as a Common name, vernacular name) is a genus of eukaryotic, unicellular ciliates, widespread in freshwater, brackish, and Ocean, marine environments. Paramecia are often abundant in stagna ...

, they are often the first

protozoa Protozoa (: protozoan or protozoon; alternative plural: protozoans) 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 ...

to appear in hay infusions, especially when the sample does not come from an existing mature source of

standing water Water stagnation occurs when water stops Environmental flow, flowing for a long period of time. Stagnant water can be a significant environmental hazard. Dangers Malaria and dengue are among the main dangers of still water, which can become ...

Habitat

''Colpoda'' are often found in moist

soil Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...

and because of their ability to readily enter protective

cysts A cyst is a closed Wikt:sac, sac, having a distinct Cell envelope, envelope and cell division, division compared with the nearby Biological tissue, tissue. Hence, it is a cluster of Cell (biology), cells that have grouped together to form a sac ...

will quite frequently be found in desiccated samples of soil and vegetation as well as in temporary

natural pool The , also referred to as Natural Pool or ("Turtle Pen"), earned its name from the historical presence of turtles in the pool. This natural saltwater tide pool is situated in the North conservation zone of Arikok National Park. Conchi is enc ...

s such as tree holes. They have also been found in the

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. T ...

s of various animals, and can be cultured from their droppings. '' Colpoda cucullus'' has been found inhabiting the surface of plants and seems to dominate the

microfauna Microfauna ( and ) are microscopic animals and organisms that exhibit animal-like qualities and have body sizes that are usually <0.1 mm. Microfauna are represented in the animal kingdom (e.g.

there. Several species of ''Colpoda'' have been found in the pitcher plant ''

Sarracenia purpurea ''Sarracenia purpurea'', the purple pitcher plant, northern pitcher plant, turtle socks, or side-saddle flower, is a carnivorous plant in the family Sarraceniaceae. Taxonomy The species is further divided into two subspecies, ''S. purpurea'' subsp. ...

'', despite the presence of

protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalysis, catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products ...

digestive enzymes in the liquid. ''Colpoda'' also tends to be found in abundance where increased levels of

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

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. In addition to inhabiting a wide variety of

microclimate A microclimate (or micro-climate) is a local set of atmosphere of Earth, atmospheric conditions that differ from those in the surrounding areas, often slightly but sometimes substantially. The term may refer to areas as small as a few square m ...

s, ''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

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

ian

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...

s in 2003. '' Colpoda irregularis'' has been found in the high

desert A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the la ...

region of Southwest

Idaho Idaho ( ) is a landlocked U.S. state, state in the Pacific Northwest and Mountain states, Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington (state), ...

. '' Colpoda aspera'' has been found in the

Antarctic The Antarctic (, ; commonly ) is the polar regions of Earth, polar region of Earth that surrounds the South Pole, lying within the Antarctic Circle. It is antipodes, diametrically opposite of the Arctic region around the North Pole. The Antar ...

. ''Colpoda'' are also found in the

arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

where warmer temperatures and longer summers lead to greater density and

species diversity Species diversity is the number of different species that are represented in a given community (a dataset). The effective number of species refers to the number of equally abundant species needed to obtain the same mean proportional species abundan ...

. 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. 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

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s, becoming dislodged hundreds or even thousands of miles away. Also, because cysts are so small and light, they can be swept by

air current In meteorology, air currents are concentrated areas of winds. They are mainly due to differences in atmospheric pressure or temperature. They are divided into horizontal and vertical currents; both are present at Mesoscale meteorology, mesoscale w ...

s into the

upper atmosphere Upper atmosphere is a collective term that refers to various layers of the atmosphere of the Earth above the troposphere and corresponding regions of the atmospheres of other planets, and includes: * The mesosphere, which on Earth lies between th ...

, and then come down on another continent.

Reproduction and conjugation

''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. 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. As in other ciliates, division in ''Colpoda'' may be preceded by a sexual phenomenon known as

conjugation Conjugation or conjugate may refer to: Linguistics *Grammatical conjugation, the modification of a verb from its basic form *Emotive conjugation or Russell's conjugation, the use of loaded language Mathematics *Complex conjugation, the change o ...

. This involves two ''Colpoda'' joining at the oral groove and exchanging

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

. Following conjugation, the ''Colpoda'' divides, redistributing the DNA of the two original cells to produce numerous genetically distinct offspring.

Ecological role

Most ''Colpoda'' species are either primarily or exclusively

bacterivore A bacterivore is an organism which obtains energy and nutrients primarily or entirely from the consumption of bacteria. The term is most commonly used to describe free-living, heterotrophic, microscopic organisms such as nematodes as well as many s ...

s feeding on a wide variety of bacteria, which include ''

Moraxella ''Moraxella'' is a genus of gram-negative bacteria in the family Moraxellaceae. It is named after the Swiss ophthalmologist Victor Morax. The organisms are short rods, coccobacilli, or as in the case of '' Moraxella catarrhalis'', diplococci ...

''. 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. In addition to their role as predators of bacteria, ''Colpoda'' are themselves prey to a large variety of species. This includes other

ns as well as small animals such as

mosquito Mosquitoes, the Culicidae, are a Family (biology), family of small Diptera, flies consisting of 3,600 species. The word ''mosquito'' (formed by ''Musca (fly), mosca'' and diminutive ''-ito'') is Spanish and Portuguese for ''little fly''. Mos ...

larva, other insect

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

, and waterfleas.

Uses by humans

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 steinii'' has been suggested as a means to assess the toxicity of soil treated with

sewage sludge Sewage sludge is the residual, semi-solid material that is produced as a by-product during sewage treatment of industrial or municipal wastewater. The term "septage" also refers to sludge from simple wastewater treatment but is connected to si ...

and as a means to detect chemical contamination in general, possibly in the wake of a

terrorist attack Terrorism, in its broadest sense, is the use of violence against non-combatants to achieve political or ideological aims. The term is used in this regard primarily to refer to intentional violence during peacetime or in the context of war a ...

Species

*'' Colpoda acuta'' - Found in central Europe, it was first described in a paper published in 1977. *'' Colpoda aspera'' - A fairly small species, 12-42 micrometres, noted for being less reniform than other species. Found in Antarctic, Subantarctic *'' Colpoda brasiliensis'' - A small species, 18-33 micrometres, noted for its mineral envelope which acts as a passive defense against predators. Named for the country in which it was discovered. *'' Colpoda californica'' *'' Colpoda cavicola'' *'' Colpoda cucullus'' - A fairly widespread species noted for being the dominant protozoan on the surface of plants. *'' Colpoda discoidea'' *'' Colpoda duodenaria'' - A small to medium-sized species, first described by Charles Vincent Taylor and Waldo Furgason and widely studied for the effects of various chemicals on its excystment process. *'' Colpoda ecaudata'' *'' Colpoda elliotti '' - A small species, 15-28 micrometres, noted as having been cultured from deer droppings. *'' Colpoda eurystoma'' *'' Colpoda fastigata'' *'' Colpoda formisanoi'' *'' Colpoda fragilis'' *'' Colpoda henneguyi'' - Widespread medium to large species, 30-80 micrometres, noted for its habit of staying perfectly still for long periods of time, making it easy to photograph live. *''

Colpoda inflata ''Colpoda inflata'' (sometimes called ''Tillina inflata'' or ''Colpoda rouxi'') is a Unicellular organism, unicellular organism, belonging to the genus Colpoda. Colpodeans are Eukaryote, eucaryotic protozoans, that mainly feed on bacteria (bacte ...

'' - Possibly one of the best known and most common species, noted for its fitful resting stage in which it jerks around in a tight circle, frustrating microscopists trying to photograph it live. *'' Colpoda irregularis'' - This species is noted for a prominent post oral sac and was cultured from

moss Mosses are small, non-vascular plant, non-vascular flowerless plants in the taxonomic phylum, division Bryophyta (, ) ''sensu stricto''. Bryophyta (''sensu lato'', Wilhelm Philippe Schimper, Schimp. 1879) may also refer to the parent group bryo ...

and soil crust from rocks near desert

sagebrush Sagebrush is the common name of several woody and herbaceous species of plants in the genus ''Artemisia (plant), Artemisia''. The best-known sagebrush is the shrub ''Artemisia tridentata''. Sagebrush is native to the western half of North Amer ...

of southwest Idaho. *'' Colpoda lucida'' *'' Colpoda magna'' - A large species, 120-400 micrometres long. Appears dark at lower powers because of dark structures near the contractile vacuole. Often completely packed with food

vacuole A vacuole () is a membrane-bound organelle which is present in Plant cell, plant and Fungus, fungal Cell (biology), cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water ...

s. *'' Colpoda maupasi'' - Once thought to be a variety of '' Colpoda steinii'', later recognized as a separate species. Classically it was believed to produce only reproductive cysts containing 8 offspring. One strain, however, the Bensonhurst strain, was found to also produce reproductive cysts containing 4 offspring. *''

Colpoda ovinucleata ''Colpoda'' is a genus of ciliates in the class Colpodea, order Tetrahymenida, Colpodida, and family Colpodidae. Description ''Colpoda'' are distinctly reniform (kidney-shaped) and are strongly convex on one side, and concave on the other. Th ...

'' *'' Colpoda patella'' *'' Colpoda penardi'' *'' Colpoda praestans'' *'' Colpoda quinquecirrata'' *'' Colpoda reniformis'' *'' Colpoda rotunda'' *'' Colpoda simulans'' - A medium-sized ''Colpoda'' with the classic "bite taken out of it" ''Colpoda'' shape. *'' Colpoda spiralis'' - A very unusual species with a large overhang that gives it an almost snail-like appearance. It was first found in Arizona and has since been reported in New Mexico and Nevada, with a possible sighting in Northern California. *'' Colpoda steinii'' - A widely distributed small to mid-sized species, 14-60 micrometres, usually free living but capable of being parasitic to

land slug Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a sma ...

s. *'' Colpoda tripartita'' *'' Colpoda variabili''

Videos

Click on images before playing them to see full size (reload (F5) if you already hit play) Image:Colpodacircus100x1.ogg, several dozen various sized ''Colpoda'' representing at least 3 species with other ciliates 100X Image:Bigcolpoda100x1.ogv, Large ''Colpoda'' amongst many smaller ones with other ciliates 100X Image:Detailedcolpoda400x1.ogg, Detailed video of ''Colpoda'' in resting stage 400X Image:Detailedcolpoda400x2.ogg, Another view of ''Colpoda'' in resting stage, showing relative sizes 400X Image:Colpodaspiralis400x1.ogg, Unusual ''Colpoda'', possibly ''Colpoda spiralis'' 400X Image:Colpodaspiralis1st.ogg, Unusual Colpoda, possibly ''Colpoda spiralis'' From when it was first spotted. Image:Colpodastuck.ogg, Several colpoda, seemingly stuck to debris 100X Image:Colpodaharrass400x1.ogg, Active ''Colpoda'' seems to harass a resting ''Colpoda'' Magnified 400 times

References

{{Authority control Colpodea Intramacronucleata Ciliate genera Articles containing video clips