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58-400: Condylostoma is a genus of unicellular ciliate protists , belonging to the class Heterotrichea . Condylostoma is a genus of heterotrichous made up of large ciliated cells. The genus was discovered by Jean Baptiste Bory de Saint-Vincent in 1826, and over 20 species have been described since then. They are mostly marine, but some are found in freshwater lakes, and they have habitats around

116-536: A genus of fish ). In the taxonomic scheme endorsed by the International Society of Protistologists , which eliminates formal rank designations such as "phylum" and "class", "Ciliophora" is an unranked taxon within Alveolata . Unlike most other eukaryotes , ciliates have two different sorts of nuclei : a tiny, diploid micronucleus (the "generative nucleus", which carries the germline of

174-399: A pellicle maintaining the cell's shape, which varies from flexible and contractile to rigid. Numerous mitochondria and extrusomes are also generally present. The presence of alveoli, the structure of the cilia, the form of mitosis and various other details indicate a close relationship between the ciliates, Apicomplexa , and dinoflagellates . These superficially dissimilar groups make up

232-413: A chain of new organisms); and palintomy (multiple fissions, usually within a cyst ). Fission may occur spontaneously, as part of the vegetative cell cycle . Alternatively, it may proceed as a result of self-fertilization ( autogamy ), or it may follow conjugation , a sexual phenomenon in which ciliates of compatible mating types exchange genetic material. While conjugation is sometimes described as

290-468: A common phenomenon but is rarely ever reported. Secondly, in contrast to initially high hopes, 18S cannot resolve nodes at all taxonomic levels and its efficacy varies considerably among clades. This has been discussed as an effect of rapid ancient radiation within short periods. Multigene analyses are currently thought to give more reliable results for tracing deep branching events in Metazoa but 18S still

348-424: A distinctive star shape, with each point being a collecting tube. Mostly, body cilia are arranged in mono- and dikinetids , which respectively include one and two kinetosomes (basal bodies), each of which may support a cilium. These are arranged into rows called kineties , which run from the anterior to posterior of the cell. The body and oral kinetids make up the infraciliature , an organization unique to

406-451: A form of reproduction, it is not directly connected with reproductive processes, and does not directly result in an increase in the number of individual ciliates or their progeny. Ciliate conjugation is a sexual phenomenon that results in genetic recombination and nuclear reorganization within the cell. During conjugation, two ciliates of a compatible mating type form a bridge between their cytoplasms . The micronuclei undergo meiosis ,

464-427: A large variety of sources between 5 μm and 40 μm in diameter, but they are not able to ingest filamentous organisms or organisms with large spines. Interestingly, they seem to show a preference for particular species, including the green aglae Kirchneriella , Dictyosphaerium , Chlamydomonas , and Cryptomanas while rejecting cyanobacteria like Dactylococcopsis , Aphanizomenan , Synedra, and Melosira . Nevertheless

522-541: A leech cocoon from the Triassic period , about 200 million years ago. According to the 2016 phylogenetic analysis, Mesodiniea is consistently found as the sister group to all other ciliates. Additionally, two big sub-groups are distinguished inside subphylum Intramacronucleata : SAL ( Spirotrichea + Armophorea + Litostomatea ) and CONthreeP or Ventrata ( Colpodea + Oligohymenophorea + Nassophorea + Phyllopharyngea + Plagiopylea + Prostomatea ). The class Protocruziea

580-464: A length of 1869 nucleotides. The universal presence of the 18S rRNA in eukaryotes and generally high degree of conservation in evolution allow the construction of universal primers for DNA amplification by polymerase chain reaction . The possible applications mirror molecular methods involving 16S rRNA of prokaryotes . Primers binding in highly conserved regions of the 18S rRNA are an important marker for biodiversity screening, allowing

638-465: A persistent selective pressure in all living beings, highlighting its potential for comparison between distantly related clades. Early studies utilizing the 18S rRNA sequence constructed the first large-scale phylogenetic trees of the metazoa . Evidence from further studies led to the creation of several important clades , such as the Ecdysozoa and Lophotrochozoa . During the latter part of

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696-417: A single gene . In Tetrahymena , the micronucleus has 10 chromosomes (five per haploid genome), while the macronucleus has over 20,000 chromosomes. In addition, the micronuclear genes are interrupted by numerous "internal eliminated sequences" (IESs). During development of the macronucleus, IESs are deleted and the remaining gene segments, macronuclear destined sequences (MDSs), are spliced together to give

754-419: A single locus ( small subunit rRNA ) or several loci (SSU rDNA, large subunit rRNA , ITS1-5.8S-ITS2 region, alpha-tubulin and COI ) showed that Condylostoma is phylogenetically related to the genera Condylostentor and Chattonidium , and with Condylostomides possibly being their sister-group. Ciliate See text for subclasses. The ciliates are a group of alveolates characterized by

812-425: A thin transparent undulating membrane around the buccal groove which is now known to be the adoral zone of membranes (AZM). These membranes can be composed of 70 to 200 polykinetids. They have a very elastic thin pellicula (membrane) surrounding the cell which can be 2 to 8 μm depending on the section. The cells are covered in longitudinal myonemes , which help make them contractile, and have trichocysts present in

870-458: Is an abundant, yet seasonal food source, so they need to be able to survive during parts of the year when algae may not be present in high quantities, or may not be present at all. Division in these cells starts with the macronucleus beads fusing to form a band before they divide in two. Some of the polykinetids are passed onto the daughter cell and then renewed in the posterior position. Both the frontal cirri and paroral membranes need to be formed in

928-440: Is ended seems to be dependent on the location of the "stop codon" in the transcript and how close they are to the 3 ′ end of the mRNA. Condylostoma tends to be fairly slow-growing when compared to other protists. They demonstrated to have a lifespan of around 6 days in their normal form, but that they could encyst if they were starved or stressed. It is hypothesized that this is due to the fact that they feed mostly on algae. This

986-633: Is found as the sister group to Ventrata / CONthreeP . The class Cariacotrichea was excluded from the analysis, but it was originally established as part of Intramacronucleata . The odontostomatids were identified in 2018 as its own class Odontostomatea , related to Armophorea . Mesodiniea Karyorelictea Heterotrichea Odontostomatea Armophorea Litostomatea Spirotrichea Cariacotrichea Protocruziea Discotrichida Colpodea Nassophorea Phyllopharyngea Oligohymenophorea Prostomatea Plagiopylea Several different classification schemes have been proposed for

1044-451: Is guided by long RNAs derived from the parental macronucleus. More than 95% of micronuclear DNA is eliminated during spirotrich macronuclear development. ln clonal populations of Paramecium , aging occurs over successive generations leading to a gradual loss of vitality, unless the cell line is revitalized by conjugation or autogamy . In Paramecium tetraurelia , the clonally aging line loses vitality and expires after about 200 fissions, if

1102-472: Is known to cause disease in humans. Ciliates reproduce asexually , by various kinds of fission . During fission, the micronucleus undergoes mitosis and the macronucleus elongates and undergoes amitosis (except among the Karyorelictean ciliates, whose macronuclei do not divide). The cell then divides in two, and each new cell obtains a copy of the micronucleus and the macronucleus. Typically,

1160-603: Is moved by the cilia through the mouth pore into the gullet, which forms food vacuoles. Many species are also mixotrophic , combining phagotrophy and phototrophy through kleptoplasty or symbiosis with photosynthetic microbes. The ciliate Halteria has been observed to feed on chloroviruses . Feeding techniques vary considerably, however. Some ciliates are mouthless and feed by absorption ( osmotrophy ), while others are predatory and feed on other protozoa and in particular on other ciliates. Some ciliates parasitize animals , although only one species, Balantidium coli ,

1218-479: Is referred to as "isogamontic" conjugation. In some groups, partners are different in size and shape. This is referred to as "anisogamontic" conjugation. In sessile peritrichs , for instance, one sexual partner (the microconjugant) is small and mobile, while the other (macroconjugant) is large and sessile . In Paramecium caudatum , the stages of conjugation are as follows (see diagram at right): Ciliates contain two types of nuclei: somatic " macronucleus " and

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1276-524: Is water—in lakes, ponds, oceans, rivers, and soils, including anoxic and oxygen-depleted habitats. About 4,500 unique free-living species have been described, and the potential number of extant species is estimated at 27,000–40,000. Included in this number are many ectosymbiotic and endosymbiotic species, as well as some obligate and opportunistic parasites . Ciliate species range in size from as little as 10 μm in some colpodeans to as much as 4 mm in length in some geleiids , and include some of

1334-468: The Condylostoma genus. Second, the species that have been described do not have as much detail as would be needed given the fact that there are few character states, otherwise known as traits, that can be used to identify cells as belonging to this genus. These are mostly benthic organisms that glide along the sediment. The gliding is done by beating the cilia throughout their body, and interestingly

1392-406: The alveolates . Most ciliates are heterotrophs , feeding on smaller organisms, such as bacteria and algae , and detritus swept into the oral groove (mouth) by modified oral cilia. This usually includes a series of membranelles to the left of the mouth and a paroral membrane to its right, both of which arise from polykinetids , groups of many cilia together with associated structures. The food

1450-617: The germline " micronucleus ". Only the DNA in the micronucleus is passed on during sexual reproduction (conjugation). On the other hand, only the DNA in the macronucleus is actively expressed and results in the phenotype of the organism. Macronuclear DNA is derived from micronuclear DNA by amazingly extensive DNA rearrangement and amplification. The macronucleus begins as a copy of the micronucleus. The micronuclear chromosomes are fragmented into many smaller pieces and amplified to give many copies. The resulting macronuclear chromosomes often contain only

1508-476: The vacuole contains are then small enough to diffuse through the membrane of the food vacuole into the cell. Anything left in the food vacuole by the time it reaches the cytoproct ( anal pore ) is discharged by exocytosis . Most ciliates also have one or more prominent contractile vacuoles , which collect water and expel it from the cell to maintain osmotic pressure , or in some function to maintain ionic balance. In some genera, such as Paramecium , these have

1566-405: The 2000s, and with increased numbers of taxa included into molecular phylogenies, however, two problems became apparent. First, there are prevailing sequencing impediments in representatives of certain taxa, such as the mollusk classes Solenogastres and Tryblidia , selected bivalve taxa, and the enigmatic crustacean class Remipedia . Failure to obtain 18S sequences of single taxa is considered

1624-571: The active genome, clustered in nucleolus organizer regions (NORs) . In ribosome biogenesis , these genes are transcribed together by the RNA polymerase I and are processed in the nucleolus structure of the nucleus . The length of the 18S rRNA varies considerably in the eukaryotic phylogenetic tree, corresponding to a range of 16S-19S in Svedberg units , with the average length commonly given as around 2000 nucleotides . The 18S rRNA of humans has

1682-431: The amount and size of food vacuoles present, they are normally more rounded towards the middle of the cell and have a blunt posterior end. The relatively small buccal groove is about 1 ⁄ 3 the size of total body length and is present ventrally on the anterior part of the cell. The buccal groove is triangular. While there are no cilia inside the groove the surrounding "lips" are covered in cilia. Early papers describe

1740-442: The amplification of unspecified or random targets from environmental samples as well as uncharacterized specimens from collections for DNA sequencing . Subsequent sequence alignment covering the less strictly conserved segments then allows the assignment of a sample to biologic clades . In the case of 18S rRNA, retrieval of DNA is improved by the abundance of repeating sequences of the rDNA within eukaryotic cells, promoting

1798-604: The cause of aging in P. tetraurelia . Until recently, the oldest ciliate fossils known were tintinnids from the Ordovician period . In 2007, Li et al. published a description of fossil ciliates from the Doushantuo Formation , about 580 million years ago, in the Ediacaran period . These included two types of tintinnids and a possible ancestral suctorian. A fossil Vorticella has been discovered inside

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1856-423: The cell is divided transversally, with the anterior half of the ciliate (the proter ) forming one new organism, and the posterior half (the opisthe ) forming another. However, other types of fission occur in some ciliate groups. These include budding (the emergence of small ciliated offspring, or "swarmers", from the body of a mature parent); strobilation (multiple divisions along the cell body, producing

1914-470: The cell line is not rejuvenated by conjugation or self-fertilization. The basis for clonal aging was clarified by the transplantation experiments of Aufderheide in 1986 who demonstrated that the macronucleus, rather than the cytoplasm, is responsible for clonal aging. Additional experiments by Smith-Sonneborn, Holmes and Holmes, and Gilley and Blackburn demonstrated that, during clonal aging, DNA damage increases dramatically. Thus, DNA damage appears to be

1972-410: The cell shows signs of aging, and the macronuclei must be regenerated from the micronuclei. Usually, this occurs following conjugation , after which a new macronucleus is generated from the post-conjugal micronucleus. Food vacuoles are formed through phagocytosis and typically follow a particular path through the cell as their contents are digested and broken down by lysosomes so the substances

2030-448: The cell), and a large, ampliploid macronucleus (the "vegetative nucleus", which takes care of general cell regulation, expressing the phenotype of the organism). The latter is generated from the micronucleus by amplification of the genome and heavy editing. The micronucleus passes its genetic material to offspring, but does not express its genes. The macronucleus provides the small nuclear RNA for vegetative growth. Division of

2088-445: The cells is rough and dark grey, with randomly dispersed granules directly below it. The cell itself is almost colorless but has a slightly grey or yellow tinge to it. No contractile vacuole was observed at least in the marine species. The cells in this genus are notoriously hard to identify for two main reasons. First, there are many morphological differences between the species in this genus making it hard to identify them as belonging to

2146-535: The ciliate phylum known to be pathogenic to humans is Balantidium coli , which causes the disease balantidiasis . It is not pathogenic to the domestic pig, the primary reservoir of this pathogen. 18S ribosomal RNA Along with the 28S and 5.8S rRNA in eukaryotes, the 18S rRNA was early identified as integral structural element of ribosomes which were first characterized by their sedimentation properties and named according to measured Svedberg units . Given its ubiquitous presence in eukaryotic life,

2204-444: The ciliates and important in their classification, and include various fibrils and microtubules involved in coordinating the cilia. In some forms there are also body polykinetids, for instance, among the spirotrichs where they generally form bristles called cirri . The infraciliature is one of the main components of the cell cortex . Others are the alveoli , small vesicles under the cell membrane that are packed against it to form

2262-431: The ciliates. The following scheme is based on a molecular phylogenetic analysis of up to four genes from 152 species representing 110 families: Some old classifications included Opalinidae in the ciliates. The fundamental difference between multiciliate flagellates (e.g., hemimastigids , Stephanopogon , Multicilia , opalines ) and ciliates is the presence of macronuclei in ciliates alone. The only member of

2320-480: The daughter cell. Condylostoma has been found to feed on the larvae of bivalves like oysters and clams. While this was only seen in a laboratory, each ciliate could ingest up to 7 larvae. At the moment the two have fairly separate niches in the wild, but if that were to change, or if Condylostoma invades a bivalve farm that could prove to have severe impacts. Condylostoma have also been tied to deteriorating coral reefs in some areas (alongside other protists). While

2378-449: The dorsal cilia tend to beat more slowly than the rest. They mostly glide forward but can turn by adjusting the posterior end of the cell, making it act as a rudder. Their standard gliding velocity is around 1mm per 2.9 seconds but they can speed up to 3 times that velocity when stimulated. Cells can also swim but are seldom seen doing this. They tend to swim in a spiral pattern due to the asymmetry of their body. When both gliding and swimming

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2436-542: The evolution of the 18S rRNA was soon proposed as marker for phylogenetic studies to resolve the evolution of eukaryotes . The 18S ribosomal RNA is the structural RNA of the small subunit in the eukaryotic cytoplasmic ribosome . The genomic sequence of the 18S rRNA is organized in a group with the 28S and 5.8S rRNA , separated and flanked by the ITS-1, ITS-2 and ETS spacer regions. These regions of ribosomal DNA (rDNA) are present with several hundred copies in

2494-483: The exact cause is not known, the current hypotheses are either that the organisms eat the bacteria that help the coral form or that they can spread bacterial diseases to the coral. In either of these cases, this can have a severe impact on the already fragile ecosystems of coral reefs. According to the World Register of Marine Species, genus Condylostoma contains 24 species: Molecular analyses based on either

2552-408: The food web as they affect many species and different types of organisms, and provide a link between bacteria and zooplankton in the food web alongside other protists. Condylostoma are very large elongated unicellular ciliates with lengths ranging from 176 to 1600 μm. They also tend to be about 7 times longer than their width. While the shape of the cell can vary depending on many factors, especially

2610-425: The genus and over 20 species have been discovered through the use of both morphological and molecular data. Condylostoma have been found around the world. Interestingly, most newly reported species from this genus seem to originate from brackish and tropical areas of Asia and Africa. In terms of habitat, they are mostly found in marine environments but some have been found in freshwater. In addition to being found in

2668-592: The globe. Morphologically they are large cells with a buccal groove that is about one third of their total length, and they are covered in cilia which grow out of their longitudinal rows of kineties. They have an adoral zone of membranelles (AZM) around the buccal groove to help capture food, but no cilia are present in the groove itself. Another feature of note is their altered genetic code. Condylostoma includes mostly benthic organisms that spend most of their time gliding along substrate looking for food. They can eat many smaller organisms between 5 μm and 40 μm in size and are

2726-555: The macronuclei disappear, and haploid micronuclei are exchanged over the bridge. In some ciliates (peritrichs, chonotrichs and some suctorians ), conjugating cells become permanently fused, and one conjugant is absorbed by the other. In most ciliate groups, however, the cells separate after conjugation, and both form new macronuclei from their micronuclei. Conjugation and autogamy are always followed by fission. In many ciliates, such as Paramecium , conjugating partners (gamonts) are similar or indistinguishable in size and shape. This

2784-524: The macronucleus occurs in most ciliate species, apart from those in class Karyorelictea, whose macronuclei are replaced every time the cell divides. Macronuclear division is accomplished by amitosis , and the segregation of the chromosomes occurs by a process whose mechanism is unknown. After a certain number of generations (200–350, in Paramecium aurelia , and as many as 1,500 in Tetrahymena )

2842-405: The main factor in its food selection seems to be morphological features like size and shape and not the taxon of the prey and there is no preference for green algae over diatoms for example). More specifically Condylostoma seems to prefer slightly larger organisms around 15 μm to 30 μm. In turn, Condylostoma have many predators, including zooplankton and insects. This makes them an important part of

2900-399: The most morphologically complex protozoans. In most systems of taxonomy , " Ciliophora " is ranked as a phylum under any of several kingdoms , including Chromista , Protista or Protozoa . In some older systems of classification, such as the influential taxonomic works of Alfred Kahl , ciliated protozoa are placed within the class " Ciliata " (a term which can also refer to

2958-501: The ocean, they are known to inhabit the Alkaline-saline lakes, or soda lakes, in tropical Africa. These lakes are only inhabited by a few groups of organisms due to their relatively extreme environment. Not only can these lakes reach up to 50 °C, but they also have low oxygen solubility and high pHs ranging from 9-12, something that showcases Condylostoma's adaptability to different environments. Condylostoma can feed on

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3016-586: The operational gene. Tetrahymena has about 6,000 IESs and about 15% of micronuclear DNA is eliminated during this process. The process is guided by small RNAs and epigenetic chromatin marks. In spirotrich ciliates (such as Oxytricha ), the process is even more complex due to "gene scrambling": the MDSs in the micronucleus are often in different order and orientation from that in the macronuclear gene, and so in addition to deletion, DNA inversion and translocation are required for "unscrambling". This process

3074-564: The organism has been observed to stop and move backwards when touching an object. Many ciliates use a slightly alternate genetic code compared to other eukaryotes. In the case of Condylostoma , stop codons have been reassigned to code for an amino acid . For these new substitutions TAA and TAG code for glutamine and TGA codes for tryptophan. The question then becomes how does Condylostoma stop translation? The answer seems to be that these codons can function both as stop codons and as normal amino acid encoders. In this case whether or not translation

3132-416: The posterior end of the cells. Being ciliates they are covered in cilia except in the buccal funnel. The cilia are oriented following the myonemes in rows. While the number of kinetosomes do not change during interphase, the length of the kineties do, to accommodate for the cell's change in size. Their cilia are long and slender, with the posterior cilia being the longest. Additionally, some research states that

3190-508: 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 (although the peculiar Suctoria only have them for part of their life cycle ) and are variously used in swimming, crawling, attachment, feeding, and sensation. Ciliates are an important group of protists , common almost anywhere there

3248-476: The prey of zooplankton and insects. Not only do they have an important role in their food webs, but they can also cause issues for humans due to their impacts on coral reefs and bivalve larvae. Condylostoma was discovered in 1826 by Jean Baptiste Bory de Saint-Vincent. The name originates from the Latin words condyle, meaning rounded end, and stoma, meaning a bodily opening. Since then much research has been done on

3306-421: The sensitivity of the analysis. Multiple properties of the genomic sequence of the 18S rRNS have established it as an important marker gene for large-scale phylogenetic analysis and the reconstruction of the metazoan tree of life . The integral role in formation and function of the ribosome is a key cause for its omnipresence in eukaryotic life. Meanwhile, the gene maintains a high degree of conservation under

3364-406: The ventral side of the cell has fewer, longer cilia than the dorsal end but this has been disputed. Additionally many species were found to have at least one frontal cirrus with some having up to four present. Looking at the interior of the cell, they are full of food vacuoles as well as cortical granules. They have a macronucleus with differing numbers of nodules ranging from 6 to 120. The pellicle of

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