As a ciliate, " C . uncinata " has cilia covering its body and a dual nuclear structure, the micronucleus and macronucleus.
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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.
In " Tetrahymena ", the micronucleus has 10 chromosomes ( 5 per haploid genome ), while the macronucleus has over 20, 000 chromosomes.
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Ciliates are also capable of sexual reproduction, and utilize two nuclei unique to ciliates : a macronucleus for normal metabolic control and a separate micronucleus that undergoes meiosis.
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Many micronucleus assays have been developed to test for the presence of these structures and determine their frequency in cells exposed to certain chemicals or subjected to stressful conditions.
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The cytokinesis-block micronucleus ( CBMN ) assay was first developed to score micronuclei in cells that completed nuclear division by blocking them at the binucleate stage before cytokinesis.
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There is apparently little, if any, DNA damage in the new macronucleus, suggesting that rejuvenation is associated with the repair of these damages in the micronucleus during meiosis.
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This species can be distinguished from its congeners by its large body size and the shape of the macronucleus; this species'micronucleus is located situated in a small macronuclear concavity.
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Unlike most other eukaryotes, ciliates have two different sorts of nuclei : a tiny, diploid micronucleus ( reproduction ), and a large, polyploid macronucleus ( general cell regulation ).
