Cytochalasin


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cytochalasin

[¦sīd·ō·kə′lā·sən]
(biochemistry)
One of a series of structurally related fungal metabolic products which, among other effects on biological systems, selectively and reversibly block cytokinesis while not affecting karyokinesis; the molecule with minor variations consists of a benzyl-substituted hydroaromatic isoindolone system, which in turn is fused to a small macrolide-like cyclic ring.

Cytochalasin

 

one of a group of related antibiotics produced by certain types of Fungi Imperfecti. Cytochalasins were isolated in 1967 by a British research group (S. B. Carter and coworkers). The cytochalasins that have been identified— designated A, B, C, D, E, and F—have the structural formula

and are differentiated by the side groups R1 and R2, representing different radicals.

Cytochalasins are crystal compounds with a molecular weight of 477 to 507 and a melting point of 182° to 270°C; they are insoluble in water but freely soluble in organic solvents. In a low concentration of 1 microgram per milliliter (μg/ml), cytochalasins inhibit the formation of an intracellular dividing membrane after the complete separation of the chromosomes that takes place in cell division, or mitosis, and thus lead to the formation of multinucleate cells. In concentrations of 10 μg/ml, cytochalasins cause the nucleus to be drawn out of the cell (enucleation). Another effect of cytochalasins is to block endocytosis in macrophages. The action of cytochalasins is reversible: upon their removal, endocytosis is reestablished; the nucleus, which having left the cell has remained connected to it by a cytoplasmic bridge, reenters the cell. Cytochalasins are believed to affect the microfilaments that are elements of the cell contraction system. Cytochalasins are used in research work in cytology and physiology.

REFERENCES

Carter, S. B. “Effects of Cytochalasins on Mammalian Cells.” Nature, 1967, vol. 213, no. 5073.
Carter, S. B. “The Cytochalasins as Research Tools in Cytology.” Endeavour, 1972, vol. 31, no. 113.

A. D. MOROZKIN

References in periodicals archive ?
The effects of cytochalasin B on the events of fertilization in the surf clam, Spisula solidissima.
The data and images are so clear; you don't have to be a bone biologist to see what cytochalasin D does in one week in a mouse.
Colchicine and cytochalasin B: a further characterization of their actions on crustacean chromatophores using the ionophore A23 187 and thiol reagents.
1997, Mycotoxins of Aspergillus clavatus: toxicity of cytochalasin E, patulin, and extracts of contaminated barley malt, J.
The compounds isolated from Phoma exigua were named phomin and dehydrophomin and those from Helminthosporium dematioideum were called cytochalasin A and B, dehydrophomin being identical to cytochalasin A and phomin to cytochalasin B.
The first method described in the literature consists of arresting oocytes at the second meiotic metaphase (MII) and chemically activating them with cytochalasin, a drug that prevents extrusion of the second polar body (17).
The murine heart was further perfused with 100 mL standard oxygenated Tyrode solu tion plus 25 [micor]L of 10 [micro]M cytochalasin D (Sigma, Missouri, USA) to block cardiac contraction.
The presence and distribution of actin, tubulin, myosin and cadherin in the meroplasmodia of a new marine ameboid algal group are studied, also the effect of cytochalasin and colchicine on the bidirectional particle transport along their reticulopodia.
Cytochalasin B slows but does not prevent monomer addition at the barbed end of the actin filament.
Genetic consequences of blocking polar body I with cytochalasin B in fertilized eggs of the Pacific oyster, Crassostrea gigas.
Cytochalasin B, a microfilament-disrupting chemical, affects cytoplasmic streaming throughout the length of radish root hairs, but the differential effects on the movement of small and large particles is interpreted to mean that both populations of microfilaments are affected (Seagull & Heath, 1980b).
In a related study, Silbergeld found the cultured cells were unable to migrate when exposed to cytochalasin B, a substance that prevents the assembly of the cellular skeleton.