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General Introductory Topics
Published in Vadim Backman, Adam Wax, Hao F. Zhang, A Laboratory Manual in Biophotonics, 2018
Vadim Backman, Adam Wax, Hao F. Zhang
Microtubules are formed by the polymers of alpha and beta tubulin. Microtubules originate (“radiate”) from the microtubule originating center (MTOC), which lies near the nucleus in association with centrioles. The role of microtubules as structural elements is to resist compression. One can think of them as support beams. Microtubules are also found in cell flagella (thus enabling cell motility) and cilia. Cilia are structures protruding from the cell surface that are used to move extracellular material, such as mucus. This function, for example, is important in the respiratory epithelium and helps get rid of foreign microorganisms or inorganic microscopic objects that are trapped in the respiratory mucus in a process called mucociliary escalator. Microtubules also assist in mitosis. Their other function is intracellular transport. Associated with motor proteins dynein and kinesin, microtubules help transport organelles like mitochondria or vesicles across a cell. In this process, dynein and kinesin attach and move toward and from, respectively, a cell center. Furthermore, in cell division (mitosis), microtubules are part of the mitotic spindle, the structure that separates the chromosomes into daughter cells.
Computational and Experimental Approaches to Cellular and Subcellular Tracking at the Nanoscale
Published in Sarhan M. Musa, ®, 2018
Zeinab Al-Rekabi, Dominique Tremblay, Kristina Haase, Richard L. Leask, Andrew E. Pelling
They are the second major ingredient of the filamentous cytoskeleton. They primarily consist of α- and β-tubulin monomers, which polymerize into filaments. Both filament monomers have a molecular weight of 55 kDa and they arrange themselves into a small hallow cylinder during polymerization. The outer diameter of the cylindrical tube is about 25nm, and interestingly microtubules have the same effective Young’s Modulus as actin (1–3 Pa); in addition these, filaments have a persistence length of about 6μm (Gittes et al. 1993). During mitosis, microtubules form mitotic spindles, which are an essential structure for the separation of chromosomes into daughter cells (Snyder and Mcintosh 1975).
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Published in Valerio Voliani, Nanomaterials and Neoplasms, 2021
Eun-Kyung Lim, Taekhoon Kim, Soonmyung Paik, Seungjoo Haam, Yong-Min Huh, Kwangyeol Lee
Certain drugs influence the synthesis or breakdown of the mitotic spindles of cells. Mitotic spindles serve as molecular railroads in the cell during cell division; they help to split the newly copied DNA such that one copy goes to each of the two new cells. These drugs disrupt formation of these spindles and therefore interrupt cell division. PTX has been developed as mitotic inhibitor for cancer chemotherapy. It binds to microtubules and interferes with the natural breakdown of microtubules during cell division [377, 381]. It is now used to treat patients with lung, ovarian, breast, and head and neck cancers as well as for prevention of restenosis.
Proteomic analysis of whole-body responses in medaka (Oryzias latipes) exposed to benzalkonium chloride
Published in Journal of Environmental Science and Health, Part A, 2020
Young Sang Kwon, Jae-Woong Jung, Yeong Jin Kim, Chang-Beom Park, Jong Cheol Shon, Jong-Hwan Kim, June-Woo Park, Sang Gon Kim, Jong-Su Seo
Microtubule-associated protein (spot 3) was significantly upregulated in BAC-exposed medaka. Microtubule-associated proteins are involved in microtubule dynamics and are essential for mitotic spindle formation and mitosis progression. Furthermore, microtubule-associated proteins play an essential role in the early developmental stages of zebrafish.[60] Also, microtubule-associated proteins are involved in the regulation of the immune response signaling of microtubules that construct eukaryotic cells and the cytoskeleton.[61] Recent evidence suggests that classical microtubule-associated proteins also guide motor protein transport, interact with the actin cytoskeleton, and are involved in various neuronal signaling networks.[62]
Les vertus des défauts: The scientific works of the late Mr Maurice Kleman analysed, discussed and placed in historical context, with particular stress on dislocation, disclination and other manner of local material disbehaviour
Published in Liquid Crystals Reviews, 2022
In cell biology, the so-called mitotic spindle describes the state of a eukaryotic cell during cell division. We remind the reader that eukaryotes are often (not always, although the reverse is the case) multi-cellular organisms with the property that the genetic material (chromosomes are contained inside a nucleus which is bounded by the nuclear envelope consisting a lipid bilayer. During cell division microtubules (long polymers) align between two spindle poles which act as the organising centres for the new nuclei. The separated (‘single helix’) chromosomes travel along the aligned microtubules to the spindle poles, eventually creating identical daughter cells.