Plasmid-related anaerobic autotrophy of the novel archaebacterium Sulfolobus ambivalens

Abstract

Three different species of the genus Sulfolobus¹, S. acidocaldarius, S. solfataricus ( = Caldariella)² and S. brierleyi³, have been distinguished⁴ by the conditions required for optimal growth, by the component patterns of their DNA-dependent RNA polymerases and by DNA sequence data. Many isolates of these species are able to grow chemolithoautotrophically using CO₂ as the sole carbon source and the oxidation of S(0) with O₂ yielding sulphuric acid, as the energy source, though a few others grow only heterotrophically. We show here that a strain of a novel Sulfolobus species, S. ambivalens, is alternatively able to live by an anaerobic mode of chemolithoautotrophy, also using CO₂ as the sole carbon source, but using reduction of S(0) with H₂, yielding H₂S as the energy source. This mode of growth is correlated with the amplification of a plasmid, pSL10.