Sulfolobus acidocaldarius DSM 639, MW001, and all constructed deletion mutants were aerobically grown in Brock media (Brock et al., 1972 (link)) with a pH of 3 at 76°C. The media were supplemented with 0.1% (w/v) tryptone or with 0.1% (w/v) N-Z-Amine and 0.2% dextrine. The growth of the cells was monitored by measurement of the optical density at 600 nm.
For pouring Sulfolobus plates a two times concentrated Brock media was supplemented with 6 mM CaCl2 and 20 mM MgCl2. For first selection plates 0.2% NZ-Amine (Fluka) and 0.4% dextrin, for second selection plates 0.2% tryptone, 0.4% dextrin, 200 μg/ml 5-FOA, and 20 μg/ml uracil was added to the two times concentrated solution and prewarmed to 75°C. This solution was mixed with an equal volume of fresh boiling 1.4% Gelrite solution (Carl Roth, Karlsruhe, Germany) and poured in 40 ml portions into petri dishes (150 × 20 mm, Sarstedt, Nümbrecht, Germany).
For pouring Sulfolobus plates a two times concentrated Brock media was supplemented with 6 mM CaCl2 and 20 mM MgCl2. For first selection plates 0.2% NZ-Amine (Fluka) and 0.4% dextrin, for second selection plates 0.2% tryptone, 0.4% dextrin, 200 μg/ml 5-FOA, and 20 μg/ml uracil was added to the two times concentrated solution and prewarmed to 75°C. This solution was mixed with an equal volume of fresh boiling 1.4% Gelrite solution (Carl Roth, Karlsruhe, Germany) and poured in 40 ml portions into petri dishes (150 × 20 mm, Sarstedt, Nümbrecht, Germany).