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.
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.
Colpidium colpoda é unha especie de protozoo ciliado de vida libre que se encontra comunmente en ambientes de auga doce, como regatos, ríos, lagos e lagoas de todo o mundo.[1] Colpidium colpoda tamén se encontra frecuentemente en plantas de tratamento de augas residuais. Esta especie utilízase como indicador da calidade da auga e do procesado das augas nas plantas de tratamento.
O primeiro rexistro de Colpidium colpoda fíxoo Losana en 1829. Describiuno mellor Christian Gottfried Ehrenberg na súa publicación en dous volumes Die Infusionsthierchen als vollkommene Organismen (que se pode traducir por “Os Infusorios como Organismos Perfectos”) de 1838. A especie foi descrita en detalle por Ganner e Foissner en 1989.[1] C. colpoda considérase un ciliado de tamaño intermedio,[2] que normalmente ten entre 16 e 30 μm de longo e son células aplanadas dorsoventralmente con varias ringleiras de cilios que discorren por toda a lonxitude da célula.[3] Como moitos outros ciliados, é un heterótrofo comedor de bacterias, que inxire pola súa fenda oral. C. colpoda reprodúcese asexualmente cada 4–6 horas,[4] e as taxas de división varían segundo as condicións ambientais e a identidade da fonte de alimento bacteriano dispoñible.[5]
En xeral, crese que os ciliados forman un grupo monofilético que diverxiu doutros eucariotas bastante cedo na historia evolutiva, despois da evolución dos sistemas xenéticos heterocarióticos, pero antes da evolución da multicelularidade e algúns orgánulos como o retículo endoplasmático e o complexo de Golgi.[6] Colpidium encádrase taxonomicamente na orde dos ciliados Hymenostomatida, que tamén inclúe ao xénero ben estudado Tetrahymena e a Glaucoma. Algúns traballos previos suxeriran que Colpidium parecía estar máis próximo a Glaucoma ca a Tetrahymena,[7] pero análises máis recentes chegan á conclusión oposta.[8]
Aínda que non se dispón dunha secuenciación do xenoma completo de Colpidium colpoda, publicáronse secuencias parciais do xene do ARNr 18S e do xene da subunidade 1 da citocromo oxidase (cox1)[9] e secuencias completas do xene do ARN da telomerase[10] e o xene de ARNr 5,8S.[11] Dentro da mesma familia taxonómica de C. colpoda está o organismo modelo Tetrahymena thermophila. Hai moita literatura científica sobre o xenoma de T. thermophila como representante dos Alveolados, unha das grandes ramas evolutivas dos eucariotas que comprende a todos os ciliados, dinoflaxelados e apicomplexos.[12] Como moitos outros ciliados, T. thermophila ten un xenoma sorprendentemente complexo situado nun micronúcleo de liña xerminal e un macronúcleo somático, que funcionan e se replican independentemente. En 2006, secuenciouse o xenoma completo do macronúcleo de T. thermophila.[13]
Como Colpidium colpoda se alimenta de bacterias, esta especie atópase en hábitats de auga doce moi polucionados. Por isto, a presenza de C. colpoda considérase un indicador de mala calidade da auga.[14] C. colpoda e os seus conxéneres tamén se usan comunmente en experimentos de laboratorio.[15] C. colpoda pode usarse para acelerar a degradación do cru durante as verteduras de petróleo durante os procesos de biorremediación,[16] aínda que o mecanismo exacto que funciona non está claro. Especúlase sobre unha secreción de mucus que actúa como emulsificante, a acción mecánica dos cilios que contribúe á emulsificación e redución da competición entre as bacterias que contribúen á degradación de hidrocarburos e aquelas outras que non, entre outras posibilidades.
Colpidium colpoda é unha especie de protozoo ciliado de vida libre que se encontra comunmente en ambientes de auga doce, como regatos, ríos, lagos e lagoas de todo o mundo. Colpidium colpoda tamén se encontra frecuentemente en plantas de tratamento de augas residuais. Esta especie utilízase como indicador da calidade da auga e do procesado das augas nas plantas de tratamento.
