Further descriptive information

Arhodomonas aquaeolei is one of the few purely chemotrophic bacteria known that is phylogenetically related to the phototrophic purple sulfur bacteria of the Gammaproteobacteria and that belongs to the phylogenetic rather coherent group of the Ectothiorhodospiraceae. According to its 16S rDNA sequence, it is genetically most similar to Halorhodospira species but is sufficiently different so as to be recognized as a separate genus (Fig. BXII.y.19of the chapter describing the family Ectothiorhodospiraceae Imhoff and Suling, 1996). The characteristic loop at position 420 (UGCG) and the addition of C in the loop covering position 1361 are also present in the sequence of Arhodomonas aquaeolei (Adkins et al., 1993). Arhodomonas shares both the requirement for high salt concentrations and the restricted spectrum of carbon sources used with Halorhodospira and Ectothiorhodospira species (Imhoff, 1989). Most carbohydrates do not support growth, but other simple organic compounds are used instead. Arhodomonas does not have the ability to perform a phototrophic type of metabolism.

*Editorial Note: Ventura et al. (2000) consider E. vacuolata a junior heterotypic synonym of E. shaposhnikovii.

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