{{short description|Living structure of cytoplasm that contains many nuclei}} {{for|the genus of parasitic protozoa which causes malaria|Plasmodium}} [[File:Hemitrichia serpula 57955.jpg|thumb|upright=1.7|Plasmodiocarp of the slime mold ''Hemitrichia serpula'': the living structure contains many nuclei, not separated from each other by cell membranes or cell walls.]]

A '''plasmodium''' is a unicellular organism, a living structure of cytoplasm that contains many nuclei, rather than being divided into individual cells each with a single nucleus.

Plasmodia are best known from slime molds, but are also found in parasitic Myxosporea, and some algae such as the Chlorarachniophyta.

==Structure==

A plasmodium is an amoeboid, multinucleate, and naked mass of cytoplasm that contains many diploid nuclei. The resulting structure, a coenocyte, is created by many nuclear divisions without the process of cytokinesis, which in other organisms pulls newly{{hyp}}divided cells apart.<ref>{{cite book | author=Sharma OP. | title=Textbook of Fungi | publisher=McGraw Hill Higher Education | location=Boston | chapter= 4. Myxomycota | chapter-url= https://books.google.com/books?id=4fcGAZBbZHAC&pg=PA33 | year=1988 | pages=33–48 | isbn=978-0-07-460329-1 | access-date= January 31, 2013}}</ref> In some cases, the resulting structure is a syncytium, created by the fusion of cells after division. Under suitable conditions, a plasmodium may differentiate and form fruiting bodies bearing spores at their tips.

==Taxonomic distribution==

The term plasmodium, introduced by Leon Cienkowski,<ref>Kuznicki, L. & Dryl, S. (1987). Leon Cienkowski. ''Acta Protozoologica'' 26 (1): 1-2, [http://rcin.org.pl/Content/9893/WA488_17670_P1825-T26-nr1_AP.pdf].</ref> usually refers to the feeding stage of slime molds; these are macroscopic mycetozoans.<ref name=Berg>{{Cite book | title=Introductory Botany: Plants, People, and the Environment | first=Linda | last=Berg | page=398 |edition=2nd | year=2008 | location=Belmont CA | publisher=Thomson Corporation | isbn=978-0-03-075453-1}}</ref>

The multinucleate developmental stages of some intracellular parasites, namely Microsporidia (now in Fungi) and Myxosporidia (now in Cnidaria), former cnidosporans, are also sometimes called plasmodia.<ref name=Hoek>Hoek, C. van den, Mann, D.G. and Jahns, H.M. (1995). Algae An Introduction to Phycology. Cambridge University Press, Cambridge. {{ISBN|0-521-30419-9}}.</ref>

Similarly, in Rhizaria, the amoeboid, multinucleate protoplasts of some Cercozoan algae, e.g. Chlorarachniophyta, are called plasmodia. These lack cell walls; the syncytia are created by cell fusion. Some plasmodiophorids and haplosporidians are other multinucleated rhizarians.<ref>Brown MW, Kolisko M, Silberman JD, Roger AJ. (2012). [http://www.cell.com/current-biology/abstract/S0960-9822(12)00413-7 Aggregative Multicellularity Evolved Independently in the Eukaryotic Supergroup Rhizaria]. ''Current Biology'', Volume 22, Issue 12, 1123-1127.</ref>

==References== {{Reflist}}

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{{Protist structures}} {{Authority control}}

Category:Eukaryote biology