Procaryote phylogeny IV: concerning the phylogenetic status of a photosynthetic bacterium.

The 16S ribosomal RNA (30S subunit) of Rhodopseudomonas spheroides has been characterized in terms of T1 ribonuclease digestion products. This "fingerprint" ultimately permits the placement of R. spheroides into a detailed procaryotic phylogenetic tree. Given the number of major procaryotic lines that have been characterized in these terms to date, one can tentatively place the Athiorhodaceae closer to the Vibrio-Enteric group than to the Bacillaceae or Cyanophyta.