Acrasidae
| Acrasid slime molds | |
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| Acrasis rosea | |
Scientific classification 
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| Domain: | Eukaryota |
| Clade: | Discoba |
| Superphylum: | Discicristata |
| Phylum: | Percolozoa |
| Class: | Heterolobosea |
| Order: | Acrasida |
| Family: | Acrasidae van Tieghem 1880 ex Hartog 1906 |
| Genera | |
| Synonyms | |
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The family Acrasidae (ICZN, or Acrasiomycota, ICBN) is a family[1] of slime molds which belongs to the excavate group Percolozoa. The name element acrasio- comes from the Greek akrasia, meaning "acting against one's judgement". This group consists of cellular slime molds.
The terms "Acrasiomycota" or "Acrasiomycetes" have been used when the group was classified as a fungus ("-mycota"). In some classifications, Dictyostelium was placed in Acrasiomycetes, an artificial group of cellular slime molds, which was characterized by the aggregation of individual amoebae into a multicellular fruiting body, making it an important factor that related the acrasids to the dictyostelids.[2]
Each cell keeps its individuality even when it forms a stalk and fruiting body to reproduce.[3] Slime molds were originally thought to be in a monophyletic group Mycetozoa, with little distinction between Acrasis and Dictyostelids, however scientists uncovered that they were distinct groups, and eventually that Acrasis was incredibly distant on the tree of life. Instead, it is found in Heterolobosia with Naegleria, away from other myxamoeba.[4]
Ecology[edit]
Acrasis is found in terrestrial habitats on dead or decaying bark or dead tissue still attached to plants.[3] They are often cultured using yeast which makes up most of their diet, but they are known to participate in cannibalism in their solitary mobile stage of life.[5] They may also be found on living tree bark.[3]
Reproduction[edit]
When resources such as water or food become limiting, the amoeba will release pheromones such as acrasin to aggregate amoebal cells in preparation for movement as a large (thousands of cells) grex or pseudopod. When in the grex, the amoeboids reproduce, resulting in fruit-like structures called spores, which develop into unicellular molds of the same species.
References[edit]
- ^ Roger AJ, Smith MW, Doolittle RF, Doolittle WF (1996). "Evidence for the Heterolobosea from phylogenetic analysis of genes encoding glyceraldehyde-3-phosphate dehydrogenase". J. Eukaryot. Microbiol. 43 (6): 475–85. doi:10.1111/j.1550-7408.1996.tb04507.x. PMID 8976605.
- ^ Cavender J.C.; Spiegl F.; Swanson A. (2002). "Taxonomy, slime molds, and the questions we ask". The Mycological Society of America. 94 (6): 968–979. PMID 21156570.
- ^ a b c Brown, M. W.; Silberman; Spiegel (2010). "A Morphologically Simple Species of Acrasis (Heterolobosea, Excavata), Acrasis helenhemmesae n. sp". Journal of Eukaryotic Microbiology. 57 (4): 346–353. doi:10.1111/j.1550-7408.2010.00481.x. PMID 20497285.
- ^ Brown, M. W.; Kolisko, M.; Silberman, J. D.; Roger, A. J. (2012). "Aggregative Multicellularity Evolved Independently in the Eukaryotic Supergroup Rhizaria". Current Biology. 22 (12): 1123–1127. doi:10.1016/j.cub.2012.04.021. PMID 22608512.
- ^ Hohl, H. R.; Hamamoto, S. T. (1969). "Ultrastructure of Acrasis rosea, a Cellular Slime Mold, During Development*". The Journal of Protozoology. 16 (2): 333–344. doi:10.1111/j.1550-7408.1969.tb02279.x. PMID 5816073.
Further reading[edit]
- C.J. Alexopolous, Charles W. Mims, M. Blackwell et al., Introductory Mycology, 4th ed. (John Wiley and Sons, Hoboken NJ, 2004) ISBN 0-471-52229-5
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