Abstract
Here we describe a new, extremely thermophilic amoeba growing between 33 °C and 57 °C (T opt. = 50 °C). Isolates had been obtained from hot springs at Agnano Terme (Italy), Yellowstone National Park (USA), Kamchatka (Russia), and the Arenal Volcano (Costa Rica). They could be cultured monoxenically on a thermophilic alpha-proteobacterium. The morphology of the amoeba was studied using a microscope situated under a heatable polyacrylate hood. At 50 °C, the cells appeared flat with an irregular triangular or elongate shape, sometimes exhibiting fine spine-like subpseudopodia. On average, they were 22 μm long and 11 μm wide and had one nucleus with a central nucleolus. Based on morphology and on SSU rRNA comparisons, the amoeba belonged to the genus Echinamoeba, where it represents a new species. Referring to its extremely thermophilic lifestyle and its hydrothermal habitat, we name it E. thermarum.
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Acknowledgements
We are indebted to R. Michel for advice in the taxonomic classification of the amoebae and to L. Amaral Zettler for providing the alignment of SSU rRNA sequences. We further thank C. Petzel for excellent technical assistance and R. Rachel for helpful discussions. This work was supported by the Deutsche Forschungsgemeinschaft (SFB 521), the Deutscher Akademischer Austausch Dienst (scholarship to A.Y.), and the Fonds der Chemischen Industrie (K.O.S.).
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Baumgartner, M., Yapi, A., Gröbner-Ferreira, R. et al. Cultivation and properties of Echinamoeba thermarum n. sp., an extremely thermophilic amoeba thriving in hot springs. Extremophiles 7, 267–274 (2003). https://doi.org/10.1007/s00792-003-0319-6
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DOI: https://doi.org/10.1007/s00792-003-0319-6