An individual mRNA species was isolated directly from lysates of Physarum polycephalum by hybridization to immobilised complementary DNA. The solvent for lysis was a 6 M-guanidinium salt solution, and the hybridization reaction was carried out at 42°C in 4 M guanidinium salt/33% (v/v) formamide buffer. The mRNA species isolated by this procedure was active in cell-free protein synthesis and directed the synthesis of a polypeptide of M r 25 500 ± 750.
