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Flabellate amoebae widespread in freshwater, soil and seawater that can be differentiated from the many other similar looking amoeba through its very distinctive glycocalyx (Figure1).  The genus Vannella was erected by Bovee (Bovee, 1965). Named species range from  V. aberdonica at 9mm to V. simplex at 80mm in diameter, although I have frequently seen flabellate amoebae with Vannella-like characteristics very much smaller than this from marine sediments.  Vannella like other flabellate amoebae seems designed to live on bio-films creeping along the flat surfaces sweeping up bacteria.  Vannella are particularly abundant on surfaces such as seaweed fronds (Rogerson, 1991).  When disturbed Vannella produces long radiant pseudopods that allow them to float off to settle on fresh surfaces.

Van2.jpg (1068656 bytes)1a 1b
Figure 1a.   An electron micrograph of the glycocalyx of Vannella sp.  showing both a longitudinal section toward the top of the image and cross-section of the glycostyles at the mid-bottom. (Maciver, S.K. unpublished).  1b. (Left) a diagram representing a single Vannella gylcostyle.  Two cross sections are shown, one (b) towards the top and another (c) towards the membrane where rays appear to support the structure like the buttresses of rain forest trees.

Vannella are known to be infected naturally with a number of bacterial species (Hoffmann et al, 1998) and to harbour human pathogens.  The genus has also been implicated with taste and odour problems in drinking water by the production of geosmin (Hayes et al, 1991). Recently Vannella sp. were  found in association with Pseudomonas aeruginosa from a chronic corneal ulcer (Michel et al, 2000), and although there was no suggestion that the amoeba was directly involved it was possible that they  protected the bacteria against the the Gentamicin and Cefalozin treatment.

So far only one species has been shown to produce cysts Vannella persistens, isolated from upland grassland in Southern, Scotland (Smirnov & Brown, 2000), although a disputed Vannella (Page, 1988), V. cutleri has been described (Singh & Hanumaiah, 1979), that also produced cysts.

An analysis of the SSUrRNA gene of Vannella angelica reveals no particular affinity to other amoeba for which similar molecular data is available (Sims et al, 1999 ), however a recent analysis (Sims et al, 2002) of partial SSUrRNA genes suggests that Vannella and Platyamoeba are related and not distinct (see the Vannellidae family). 


Vannella at the Protist Information Server


  the Vannellidae family
Described species:-
V. anglica (Page, 1980).  Marine. 15 - 37mm in length, nucleus 5mm in diameter.  SSUrDNA sequence data is available (Sims et al, 1999).
V. aberdonica (Page, 1980). Marine. 6.5 - 13mm nucleus 2.6mm. Floating form not radiant.
V. arabica (Page, 1980). Marine. 
V. caledonica (Page, 1979). Marine. 10 - 25mm in length nucleus 5mm in diameter. Floating form rounded but not radiant.
V. cirrifera (Page, 1988). 
V. crassa (Schaeffer, 1926). Originally described as Flabellula crassa, later reclassified (Page, 1983).
V. devonica (Page, 1979). Marine
V. lata 
V. mira (Schaeffer, 1926). Originally described as Flabellula mira, later reclassified (Page, 1983) however this has recently been questioned (Smirnov, 2002).
V. peregrinia (Smirnov & Fenchel, 1996).  An anaerobic amoeba with atypical mitochondria.  Length average 9mm and breadth 8mm. 
V. persistens (Smirnov & Brown, 2000). Terrestrial soil. The only cyst forming Vannella to date!  
V. platypodia ().  Freshwater. Known to contain cytoplasmic microtubules (Smirnov, 1995)
V. sensilis (Bovee & Sawyer 1979)
V. septentrionalis (Page, 1980). 15-33mm in length nucleus 4.5mm in diameter. Floating form rounded but not radiant.
V.  simplex ()
Strains available (SSUrDNA sequence Genbank numbers in black):-
Vannella sp. ATCC 30947 Griffin, 1962, Marine, Alewife cove, Waterford, CT USA
Vannella aberdonica ATCC50815 Peglar, Marine. AY121853
Vannella anglica CCAP 1589/8, CCAP 1589/11, Marine, Walberswick, Suffolk, England.UK  AF099101
Vannella arabica CCAP 1589/7, Marine, Kuwait
Vannella devonica CCAP 1589/5, Marine, Kingsbridge estuary, Devon, England. UK.
Vannella lata CCAP 1589/12, Freshwater, Loch Morar, Scotland. UK. 
Vannella mira CCAP 1589/15, Saline water, Camarque, France.
Vannella miroides ATCC 30945 Griffin, 1963, Freshwater, Harvard Med School USA AY183888
Vannella platypodia CCAP 1589/2, Freshwater, Indiana, USA.
Vannella septentrionalis CCAP1589/10, Marine, River Don estuary, Scotland UK.
Vannella simplex CCAP 1589/3 Freshwater, Pool, Bonn, Germany.

Anderson, O. R. (1998) Densities and diversity of Gymnamoebae in relation to some inshore aquatic habitats in Berbunda  J.Eukaryotic Microbiol. 45, 151-155.

Ariza, C., Guevara, D.C., Ubeda, J.M., & Cutillas, C. (1989). Description of four species of the genus Vannella isolated from freshwater. Microbiologia SEM 5: 25-33.

Bovee, E.C. (1965). An emendation of the ameba genus Flabellula and a description of Vannella gen. nov. Trans.Am.Micros.Soc. 84:  217-227.

Hayes, S.J., Hayes, K.P. & Robinson, B.S. (1991). Geosmin as an odorous metabolite in cultures of a free-living amoeba, Vannella species (Gymnamoebia, Vannellidae).  J.Protozool. 38(1): 44-47.

Hoffmann, R., Michel, R., Schmid, E.N. & Muller, K.-D. (1998). Natural infection with microsporidian organisms (KW19) in Vannella spp. (Gymnamoebia) isolated from a domestic tap-water supply. Parasitol.Res. 84: 164-166.

Michel, R., Schmid, E.N., Boker, T., Hager, D.G., Muller, K.D., Hoffman, R. & Seitz, H.M. (2000). Vannella sp. harboring microsporidia-like organisms isolated from the contact lens and inflamed eye of a female keratitis patient. Parasitol.Res. 86(6), 514-520.

Page, F.C. (1980). A key to marine species of Vannella (Sarcodina, Gymnamoebia), with descriptions of new species. J.Mar.Biol.Ass.U.K. 60, 929-946.

Page, F.C. (1978). Two genera of marine amoebae (Gymnamoebia) with distinctive surface structures: Vannella Bovee, 1965 and Pseudoparamoeba n.gen., with two new species of Vannella. Protistologica, 15, 245-257. 

Page, F. C. (1988) A new key to freshwater and soil gymnamoebae. Culture Collection of Algae and Protozoa.

Peglar, M. T., Amaral Zettler, L. A., Anderson, O. R., Nerad, T. A., Gillevet, P. M., Mullen, T. E., Frasca Jr, S., Silverman, J. D., O'Kelly, C. J. & Sogin, M. L. (2003) Two new small-subunit ribosomal RNA gene lineages within the subclass Gymnamoebia. J.Eukaryot.Microbiol. 50, 224-232.

Rogerson, A. (1991). On the abundance of marine amoebae on the surfaces of five species of macroalgae. FEMS Microb.Ecol. 85, 301-312.

Rohr, U., Weber, S., Michel, R., Selenka, F. & Wilhelm, M. (1998) Comparison of free-living amoebae in hot water systems of hospitals with isolates from moist sanitary areas by identifying genera and determining temperature tolerance. App.Environ.Microbiol. 64, 1822-1824.

Sims, G.P., Anderson, A. & Aitken, R. (1999). Primary and secondary structure of the small-subunit ribosomal RNA of the naked , marine amoeba Vannella anglica: phylogenetic implications. J.Mol.Biol. 48, 740-749.

Sims, G. P., Aitken, R. & Rogerson, A. (2002) Identification and phylogenetic analysis of morphologically similar naked amoebae using small subunits ribosomal RNA. J.Eukaryot.Microbiol. 49, 478-484.

Singh, B.N. & Hanumaiah, V. (1979). Studies on pathogenic and non-pathogenic amoebae and the bearing of nuclear division and locomotive form and behaviour on the classification of the order Amoebida. Monograph No 1, Association of Microbiologists of India.  Ind.J.Microbiol. 1-80.

Smirnov, A.V. & Fenchel, T. (1996). Vahlkampfia anaerobica n.sp. and Vannella peregrina n.sp. (Rhizopoda) - anaerobic amoebae from a marine sediment. Arch.Protistenkd. 147, 189-198.

Smirnov, A.V. & Brown, S.(2000). First isolation of a cyst-forming Vannella species, from soil - Vannella persistens n. sp. (Gymnamoebia, Vannellidae). Protistologica 1(3), 120-123.

Smirnov, A. (2002) Re-description of Vannella mira Schaeffer 1926 (Gymnamoebia, Vannellidae), an often mentioned but poorly known amoebae species, Protistologica. 2 (3) (2002), 178-184.

Sogin, M. L., Silberman, J.D, Hinkle, G. & Morrison, H.G. (1996). Problems with molecular diversity in the eukarya. Society of General Microbiology Symposium: Evolution of microbial Life ed.Roberts, D.M., Sharp, P., Alderson, G. & Collins, M.A. Cambridge University Press. pp167-184.

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