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Heteramoeba

updated 11/5/03

The only known species of the genus is Heteramoeba clara isolated from supra-littoral rock pools beneath a colony of Gannets (sea birds, Sula bassana ) on the rocky island Ailsa Craig off the west coast of Scotland in the Firth of Clyde (Droop, 1962). In four of the 35 rock pools sampled Heteramoeba were abundant (Droop, 1966).  These rock pools were described as being brackish and Heteramoeba clara can survive at salinities as low as 2 %o (Droop, 1966)Droop, 1966)Page, 1983).

Fig.1 Left Ailsa Craig.  Right the Gannet  colony. The amoeba Heteramoeba clara was isolated from rock pools at the bottom of this colony in August 1960 by M.R. Droop.

Pictures courtesy of Davie Law and the Maybole Community Council

Fig.2
The phylogenetic position of the amoeba seems fairly clear, as it resembles the genus Naegleria in so many ways, including locomotory habit, and the fact that it like Naegleria (and other Vahlkampfidae) is an encysting amoeboflagellate.  Genetic data (SSUrDNA sequence) indicate too that Heteramoeba belong in this group (Sogin et al, 1996; Silberman et al, 2002), (Fig. 3).
Fig. 3. Phylogenetic relationship of some members of the Vahlkampfia and related amoeba based on SSUrRNA gene analysis (Clustal X), using the barely related Entamoeba as an outgroup. Some names have been changed in accordance with recent suggestions (Brown  & De Jonckheere, 1999).  This figure illustrates the huge diversity present in the SSUrRNA gene itself and by inference at least, in these organisms genome in general.  The Heteramoeba clara SSUrRNA gene sequence was from (Silberman et al, 2002).

Psalteriomonas

Sawyeria

Paravahlkampfia

Neovahlkampfia

Vahlkampfia

Tetramitus

At the electron microscope level, Heteramoeba clara  Carey & Page, 1985).  The nucleus was multilobed with parietal nucleolar material, at the light microscope level sometimes the nucleoli was central as it usually is in Naegleria. Dividing amoeba were observed and found to be promitotic, that is the nuclear envelope does not break down and the polar masses (chromosomes) move to either end of the nucleus.
Fig. 4.  Diagram showing the two active stages of Heteramoeba clara. Left the Flaggellate.  The body is approximately spherical up to 30mm in diameter. Two flagellae of equal length (60mm) arising form the top of the cytosome, a mouth-like apparatus that allows the cell to feed on large prey. the cytosome has a pronouced lip. Right the amoeba. with hyaline pseudopod devoid of visible vesicles or other organalles at top, uroid at bottom. The uroid often produces trailing extensions and is associated with bacteria and other detritus.
Available strains:-
H. clara CCAP1536/1  Droop 1960 Ailsa Craig, Firth of Clyde, Scotland (Same strain as ATCC30972)
H. clara ATCC 30972 Balamuth, 1960 Ailsa Craig, Firth of Clyde, Scotland (Same strain as CCAP1536/1)

 

References

Carey, P. G. and F. C. Page (1985). "A light and electron microscopic study of the marine amoeboflagellate Heteramoeba clara Droop 1962." Arch.Protistenk. 130: 313-328.

Droop, M. R. (1962). "Heteramoeba clara n.gen, n.sp., a sexual biphasic amoeba." Archiv Für Mikrobiol. 42: 254-266."

Droop, M. R. (1966). "The role of algae in the nutrition of Heteramoeba clara Droop, with notes on Oxyrrhis marina Dujardin and Philodina roseola" Ehrenberg. London, George Allen and Unwin Ltd.

Page, F.C. (1983). "Marine Gymnamoebae." Inst.Terr.Ecol. NERC Cambridge, England.

Silberman, J. D., Simpson, A. G. B., Kulda, J., Cepicka, I., Hampl, V., Johnson, P. J. & Roger, A. J. (2002) Retromonad flagellates are closely related to diplomonads- Implications for the history of mitochondrial function in eukaryotic evolution. Mol.Biol.Evol. 19, 777-786.

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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