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Name derivation:
“Restless” A- without; -stasia static
Classification:
Astasia Ehrenberg 1830; Astasia Dujardin 1841 describing colorless cells (Leedale 1967); 35 or 159 species descriptions are recognized Class Euglenophyceae; Order Eutreptiales
Morphology:
Free swimming unicell, colorless osmotroph (heterotroph), 10 – 75 µm long, with two emergent flagella. Also phagotrophic if Euglenopsis species are considered to be synonymous. One emergent flagellum, a second terminated within the ‘reservoir’. No eyespot. Metaboly similar to Euglena.
Similar genera:
Euglena has an eyespot and is either photosynthetic or osmotrophic. Euglenopsis is phagotrophic, and here is treated as a synonym for the phagotrophic species of Astasia.
Cytotoxin production:
Astasia longa contains a novel cytotoxic carbohydrate-conjugated ergosterol called 'astasin' comprising ~2 – 3% of the cell lipid content. Human lymphoma HL 650 cells were growth-inhibited when cultured with 5 µg astasin per ml of medium, and completely inhibited with 50% cell death at 10 5 µg Kaya, Sano and Shiraishi 1995)..
Habitat:
Organotrophic freshwater
References:
Ehrenberg, C.G. 1830. Beitrage zur Kenntniss der Organisation der Infusorien und ihrer geographischen Verbreitung, besonders in Sibirien. Physikalische abhandlungen der Koniglichen Akadamie der Wissenschaften zu Berlin (88 pp). Dujardin, F. 1841. Histoire Naturelle des Zoophytes-Infusoires. Paris: Roret. Guiry, M.D. and G.M. Guiry 2012. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 05 December 2012. Leedale, G.F. 1967. Euglenoid Flagellates. Prentice Hall (242 pp). Kaya, K., T. Sano and F. Shiraishi 1995. Astasin, a novel cytotoxic carbohydrate-conjugated ergosterol from the colorless euglenoid, Astasia longa. Biochim Biophys Acta 1255(2):201-204.
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