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Procentriole
A procentriole ( ) is a centriole or basal body in a stage of early development. That is, it is what is to become a set of triplets of microtubules destined to form spindles of fibres that will separate chromosomes during mitosis and in order to act as anchoring sites for some proteins. Procentrioles are generally assembled canonically in association with pre-existing centrioles that are loosely connected to each other. The environment suitable for procentriole formation is provided by the base of each centriole. Procentrioles assemble perpendicular to existing centrioles. A cylindrical structure with a diameter around 130 nm forms at the onset of assembly. Free microtubules elongate the initial cylindrical structure of procentrioles to form centrioles. An alternative way of procentriole assembly has also been discovered. Instead of forming in the vicinity of pre-exisintg centrioles, this “de novo” pathway is activated during ciliogenesis, in which many procentrioles are synt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centriole
In cell biology a centriole is a cylindrical organelle composed mainly of a protein called tubulin. Centrioles are found in most eukaryotic cells, but are not present in conifers ( Pinophyta), flowering plants ( angiosperms) and most fungi, and are only present in the male gametes of charophytes, bryophytes, seedless vascular plants, cycads, and '' Ginkgo''. A bound pair of centrioles, surrounded by a highly ordered mass of dense material, called the pericentriolar material (PCM), makes up a structure called a centrosome. Centrioles are typically made up of nine sets of short microtubule triplets, arranged in a cylinder. Deviations from this structure include crabs and '' Drosophila melanogaster'' embryos, with nine doublets, and ''Caenorhabditis elegans'' sperm cells and early embryos, with nine singlets. Additional proteins include centrin, cenexin and tektin. The main function of centrioles is to produce cilia during interphase and the aster and the spindle du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal Body
A basal body (synonymous with basal granule, kinetosome, and in older cytological literature with blepharoplast) is a protein structure found at the base of a eukaryotic undulipodium ( cilium or flagellum). The basal body was named by Theodor Wilhelm Engelmann in 1880 It is formed from a centriole and several additional protein structures, and is, essentially, a modified centriole. The basal body serves as a nucleation site for the growth of the axoneme microtubules. Centrioles, from which basal bodies are derived, act as anchoring sites for proteins that in turn anchor microtubules, and are known as the microtubule organizing center (MTOC). These microtubules provide structure and facilitate movement of vesicles and organelles within many eukaryotic cells. Assembly, structure Cilia and basal bodies form during quiescence or the G1 phase of the cell cycle. Before the cell enters G1 phase, i.e. before the formation of the cilium, the mother centriole serves as a compone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid Body
An asteroid body is a microscopic finding seen within the giant cells of granulomas in diseases such as sarcoidosis and foreign-body giant cell reactions. There is controversy about their composition. Traditionally, they were thought to be cytoskeletal elements and to consist primarily of vimentin. However, more recent research suggested that that was incorrect and that they may be composed of lipids arranged into bilayer membranes. They were also once thought to be related to centrioles, an organelle involved in cell division in eukaryotes. See also *Asteroid *Centriole In cell biology a centriole is a cylindrical organelle composed mainly of a protein called tubulin. Centrioles are found in most eukaryotic cells, but are not present in conifers (Pinophyta), flowering plants (angiosperms) and most fungi, and a ... * Schaumann body * Granulomatous diseases * Sarcoidosis Additional images Image:Asteroid body intermed mag.jpg, Micrograph of asteroid bodies in pulm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
