Tetramitus

Introduction

The genus Tetramitus contains species that can or cannot transform to the flagellate stage, as is the case in the genus Naegleria. At present 15 species are recognized in the genus. Although all belong to the genus Tetramitus, the cyst morphology varies much more between Tetramitus spp. (Fig. 1) than in the genus Naegleria. The cyst can have a smooth wall or a wrinkled outer wall, both with no pores such as in T. wacamawensis, T. ovis and T. jugosus, one pore such as in T. horticolus, or several pores such as in T. angularis. This high variation in cyst morphology lead some investigators to erect different genera for some isolates that were later placed within Tetramitus by molecular data (Brown and De Jonckheere 1999, De Jonckheere and Brown 2005).

Click on an image to view larger version & data in a new window

Fig. 1. Cysts of Tetramitus spp. Top: Tetramitus wacamawensis, Tetramitus ovis, and Tetramitus jugosus. Bottom: Tetramitus horticolus and Tetramitus angularis. © Johan F. De Jonckheere.

In the genus Tetramitus an extremophile has been detected, T. thermacidophilus which grows in a pH range of 1.2 – 5 and a temperature up to 54°C (Baumgartner et al. in press).

References

Baumgartner, M., Eberhardt, S., De Jonckheere, J. F., Stetter, K. O. Tetramitus thermacidophilus n. sp., an amoeboflagellate from acidic hot springs. J. Eukaryot. Microbiol. in press.

Brown, S., De Jonckheere, J.F. A reevaluation of the amoeba genus Vahlkampfia based on SSUrDNA sequences. Europ. J. Protistol. 35, 49-54, 1999.

De Jonckheere, J. F. Molecular identification of free-living amoebae of the Vahlkampfiidae and Acanthamoebidae isolated in Arizona (USA). Europ. J. Protistol. 43, 9-15, 2007.

De Jonckheere, J. F., Brown, S. The identification of vahlkampfiid amoebae by ITS sequencing. Protist 156, 89-96, 2005.

De Jonckheere, J. F., Brown, S. Isolation of a vahlkampfiid amoeba from a contact lens: Tetramitus ovis (Schmidt, 1913) n. comb. Europ. J. Protistol. 41, 93-97, 2005.

De Jonckheere, J. F., Brown, S., Walochnik, J., Aspöck, H., Michel, R. Morphological investigation of three Tetramitus spp. which are phylogenetically very closely related: Tetramitus horticolus, Tetramitus russelli n. comb. and Tetramitus pararusselli n. sp. Europ. J. Protistol. 41, 139-150, 2005.

Murtagh, G. J., Dyer, P. S., Rogerson, A., Nash, G. V., Laybourn-Parry, J. A new species of Tetramitus in the benthos of a saline antarctic lake. Europ. J. Protistol. 37, 437-443, 2002.

Page, F. C. A New Key to Freshwater and Soil Gymnamoebae. Freshwater Biological Association, Ambleside, Cumbria, 1988.

Robinson B. S., De Jonckheere J. F., Dobson P. J. New Tetramitus species (Heterolobosea, Vahlkampfiidae) from cold aquatic environments. Europ. J. Protistol. 43, 1-7, 2007.