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The
genus includes small uni-nucleate amoebae with spiny appearance that
produces smooth spherical cysts. The amoeba are about 10-15
mm
long and the cysts are about 8
mm
in diameter. Echinamoeba cysts do not have pores and appear
to have thin walls.
Echinamoeba
bears a resemblance to
Acanthamoeba, but despite this, a
number of studies comparing SSUrRNA gene sequences suggests that Echinamoeba is
most closely related to Hartmannella
(Amaral-Zettler et al, 2000;
Bolivar et al, 2001;
Baumgartner et al, 2003;
Peglar et al, 2003).
The analysis of relations within the Echinamoeba group will be
complicated by the fact that it is possible to isolate more than one
sequence from some strains using the standard SSUrRNA gene primers (Baumgartner
et al, 2003)
as they contain more than one gene.
Echinamoeba has not
been found to be pathogenic but the amoeba was identified along with
Acanthamoeba and Naegleria from a necrotic lesion in the tail
of a Basiliscus lizard (Walochik
et al, 1999).
Echinamoeba support the intracellular growth of pathogenic
Pseudomonas bacteria associated with an out break in a hospital (Michel
et al, 1995).
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| References:-
Amaral Zettler, L. A., Nerad, T. A.,
O'Kelly, C. J., Peglar, M. T., Gillevet, P. M., Silberman, J. D. & Sogin,
M. L. (2000) A molecular reassessment of the Leptomyxid amoebae.
Protist. 151, 275-282.
Baumgartner, M., Yapi, A., Grobner-Ferreira,
R. & Stetter, K. O. (2003) Cultivation and properties of Echinamoeba
thermarum n.sp., an extremely thermophilic amoeba thriving in hot
springs. Extremophiles. 7, 267-274.
Bolivar, I., Fahrni, J. F., Smirnov, A.
& Pawlowski, J. (2001) SSU rRNA-based phylogenetic position of the genera
Amoeba and Chaos (Lobosea, Gymnamoebia): The origin of
gymnamoebae revisited. Mol.Biol.Evol. 18, 2306-2314.
Jahn,
Bovee & Griffiths, 1974
Page, F.C. (1993). "Marine Gymnamoebae".
Cambridge Inst.Terr.Ecol. NERC
Michel, R., Burghardt, H. & Bergmann,
H. (1995) Acanthamoeba, naturally intracellularly infected with
Pseudomonas aeruginosa, after their isolation from a
microbiologically contaminated drinking water systemin a hospital.
Zentralbl. Hyg. Umweltmed. 196, 532-544.
Walochnik, J., Hassl, A., Simon, K.,
Benyr, G. & Aspöck, H. (1999) Isolation and identification by partial
sequencing of the 18S ribosomal gene of free-living amoebae from
necrotic tissue of Basiliscus plumifrons (Sauria: Iguanidae).
Parisitol.Res. 85, 601-603.
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