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Name derivation: |
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Hanusia is named in memory of the Czech phycologist Hanŭs Ettl (1931-1997) See memorial: Phycologia (1997) Volume 36(6):517-523 online |
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Classification: |
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Hanusia phi J.A. Deane 1998; one species has been described and is accepted taxonomically (Guiry and Guiry 2014).Order Pyrenomonadales; Family GeminigeraceaePreviously called Cryptomonas sp. Φ (Guillard 1963), an undescribed cryptomonad treated as a model for studies of the endosymbiotic origin of polastids.
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Morphology: |
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Biflagellate unicell 5-10 µm long and 3-5 µm wide with a furrow half the length of the cell lined with large ejectosomes. Cells have one plastid, or two presumably immediately prior to cell division, containing Cr-phycoerythrin 545 as the major biliprotein (Deane et al. 1998). |
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Ultrastructure: |
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Not visible in the light microscope are rosulate scales forming a dense mat over the periplast. More ultrastructure includes many small ejectisomes under the periplast, especially toward the posterior of the cell (Deane et al. 1998). |
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Photosynthetic Endosymbiont: |
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The presence of an endosymbiont in cryptomonads was discovered and confirmed in Hanusia phi, then called 'Cryptomonas sp. Φ' that retained its own small nucleus encoding its own rRNAs, presumably incorporating them into its own ribosomes different from those produced by the host nucleus. Further the two types of ribosomes didn’t mix but remained separated by the membrane surrounding the endobiont. The endobiont occupies a small fraction of the host’s volume (McFadden et al. 1994). |
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Similar genera: |
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Teleaulax Hill 1991 and Proteomonas Hill 1991 have different 18S rRNA sequences (Hill and Saunders, unpublished data). |
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Habitat: |
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Marine plankton. |
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References: |
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Deane, J.A., D.R.A. Hill, , S.J. Brett, and G.I. McFadden 1998. Hanusia phi gen. et sp. nov. (Cryptophyceae): characterization of 'Cryptomonas sp. Φ'. European Journal of Phycology 33: 149-154, 13 figs. Guillard, R.R.L. (1963). Organic sources of nitrogen for marine centric diatoms. In Symposium on Marine Microbiology (Oppenheimer, C.H. editor), 93–104. Thomas, C.C., Springfield, IL. Guiry, M.D. and G.M. Guiry 2014. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 21 February 2013. McFadden, G.I., P.G. Gilson and S.E. Douglas 1994. The photosynthetic endosymbiont in cryptomonad cells produces both chloroplast and cytoplasmic-type ribosomes. Journal of Cell Science 107: 649–657. |
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