|This article needs additional citations for verification. (April 2009)|
Multinucleate cells (also called multinucleated or polynuclear cells) are eukaryotic cells that have more than one nucleus per cell, i.e., multiple nuclei share one common cytoplasm. Mitosis in multinucleate cells can occur either in a coordinated, synchronous manner where all nuclei divide simultaneously or asynchronously where individual nuclei divide independently in time and space. The multinucleate stage in the life cycle of some organisms is called plasmodium.
Although not normally viewed as a case of multinucleation, plant cells share a common cytoplasm by plasmodesmata, and most cells in animal tissues are in communication with their neighbors via gap junctions.
Mechanisms and types
- Syncytia (formed by cell fusion) and
- Coenocytes (formed by nuclear division not being followed by cytokinesis).
Multinucleate cells can occur naturally under physiological conditions by the fusion of the plasma membranes of cells thus forming syncytia. Examples include the skeletal muscle cells of mammals, the tapetal cells of plants, and the storage cells of Douglas-fir seeds. The polymorphonuclear lymphocytes of mammals are not polynuclear cells, although the lobes of their nuclei are so deeply bifurcated that they can appear so under suboptimal microscopy.
The chlorarachniophytes form multinucleate cells by fusion, being syncytia and not coenocytes. This syncytia is called plasmodium, in the sense of a multinucleate protoplast without a cell wall which exhibits amoeboid movement. Other examples include some plasmodiophorids, some haplosporidians, and the grex of cellular slime moulds (dictyostelids and acrasids).
Furthermore, multinucleate cells are produced from specialized cell cycles in which nuclear division occurs without cytokinesis, thus leading to large coenocytes or plasmodia. In filamentous fungi, multinucleate cells may extend over hundreds of meters so that different regions of a single cell experience dramatically different microenvironments. Other examples include, the plasmodia of plasmodial slime molds (myxogastrids) and the schizont of the Plasmodium parasite which causes malaria.
- Boyd, J. D.; Hamilton, W. J. (1966). "Electron microscopic observations on the cytotrophoblast contribution to the syncytium in the human placenta". Journal of anatomy 100 (Pt 3): 535–548. PMC 1270795. PMID 5965440.
- Read, Nick D.; Roca, Gabriela M. (2006). "Chapter 5: Vegetative Hyphal Fusion in Filamentous Fungi". In Baluška, František; Volkmann, Dieter; Barlow, Peter W. Cell-Cell Channels. Landes Bioscience and Springer Science+Business Media. pp. 87–98. ISBN 978-0-387-36058-4.
- Von Aderkas, P.; Rouault, G.; Wagner, R.; Chiwocha, S.; Roques, A. (2005). "Multinucleate storage cells in Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) and the effect of seed parasitism by the chalcid Megastigmus spermotrophus Wachtl". Heredity 94 (6): 616–622. doi:10.1038/sj.hdy.6800670. PMID 15829985.
- Hoek, C. van den, Mann, D.G. and Jahns, H.M. (1995). Algae An Introduction to Phycology. Cambridge University Press, Cambridge
- Brown MW, Kolisko M, Silberman JD, Roger AJ. (2012). Aggregative Multicellularity Evolved Independently in the Eukaryotic Supergroup Rhizaria. Current Biology, Volume 22, Issue 12, 1123-1127.
|This cell biology article is a stub. You can help Wikipedia by expanding it.|