{{Short description|Cell type in the circulatory system of invertebrates}} [[File:The Biological bulletin (19755895134).jpg|thumb|The cytoskeleton of a ''Limulus'' (horseshoe crab) amebocyte]]
An '''amebocyte''' or '''amoebocyte''' ({{IPAc-en|ə|ˈ|m|iː|b|ə|s|aɪ|t}}) is a motile cell (moving like an amoeba) in the bodies of invertebrates including cnidaria, echinoderms, molluscs, tunicates, sponges, and some chelicerates.
Moving by pseudopodia, amebocytes can manifest as blood cells or play a similar biological role.
In older literature, the term ''amebocyte'' is sometimes used as a synonym of ''phagocyte''.
== Purpose == Similarly to some of the white blood cells of vertebrates, in many species amebocytes are found in the blood or body fluid (e.g. as the blood cells of ''Limulus'', the horseshoe crab)<ref name=":0" /> and play a role in the defense of the organism against pathogens. Depending on the species, an amebocyte may also digest and distribute food, dispose of wastes, form skeletal fibers, fight infections, and change into other cell types.
[[File:The Biological bulletin (20191724949).jpg|thumb|Immature ''Limulus'' granules]]
== Examples ==
In sponges, amebocytes, also known as archaeocytes, are cells found in the mesohyl that can transform into any of the animal's more specialized cell types.<ref>{{Cite web|url=http://faculty.fmcc.suny.edu/mcdarby/animals&plantsbook/animals/02-Sponges&Cnidaria.htm|title=An Online Introduction to the Biology of Animals and Plants - Sponges and Cnidaria|last=|first=|date=|website=|access-date=}}</ref>{{dead link|fix-attempted=yes|date=January 2024}}<ref>{{Cite web|url=https://www.ncsu.edu/project/bio402_315/lec%203%20porifera/Porifera%202013.html|title=The Porifera - Invertebrate Biology Course|last=|first=|date=|website=|access-date=}}</ref>{{dead link|fix-attempted=yes|date=January 2024}}
In tunicates they are blood cells and use pseudopodia to attack pathogens that enter the blood, transport nutrients, get rid of waste products, and grow/repair the tunica.<ref>{{Cite journal|last=Cima|first=Francesca|last2=Ballarin|first2=Loriano|last3=Gasparini|first3=Fabio|last4=Burighel|first4=Paolo|date=2006-01-01|title=External amebocytes guard the pharynx entry in a tunicate (Ascidiacea)|journal=Developmental & Comparative Immunology|volume=30|issue=5|pages=463–472|doi=10.1016/j.dci.2005.07.004|pmid=16182366}}</ref>
The amebocytes of ''Limulus'' are characterized by large granules around the nucleus, ribosome-like particles in the cytoplasm, and a circumferential ring of microtubules, which likely help maintain the cells' prolate-to-fusiform shape.<ref name=":0">{{Cite journal |last=Copeland |first=D. Eugene |last2=Levin |first2=Jack |date=1985 |title=The Fine Structure of the Amebocyte in the Blood of Limulus polyphemus. I. Morphology of the Normal Cell |url=https://www.jstor.org/stable/1541494 |journal=Biological Bulletin |volume=169 |issue=2 |pages=449–457 |doi=10.2307/1541494 |issn=0006-3185}}</ref>
==Uses== Limulus amebocyte lysate, an aqueous extract of amebocytes from the Atlantic horseshoe crab (''Limulus polyphemus''), is commonly used in a test to detect bacterial endotoxins.<ref>{{cite journal |author=Levin J, Bang F.B. |year=1968 |title=Clottable Protein in Limulus: Its Localization and Kinetics of Its Coagulation by Endotoxin |journal=Thromb. Diath. Haemorrh |volume=19 |issue=1 |pages=186–97 |pmid=5690028}}</ref>
==References== {{reflist}}
==External links== * {{Commons category-inline}}
Category:Motile cells Category:Invertebrate immunology
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