Fig. 5
From: Optimized sampling protocol for mass spectrometry-based metabolomics in Streptomyces
a Full mass balances of all determinable metabolites. Meth60: 60% methanol at − 30 °C; AceB: acetone; ProB: propanol; IsoaB: isoamylol; MethB: methanol with base solution 5:1 (v/v) at − 30 °C, respectively. The base solution consisted of acetone: ethanol = 1:1 (mol/mol). QS: quenching supernatant; IC: intracellular; TB: total broth; and EC: extracellular. TB-EC: calculated ‘true’ intracellular metabolites. b Effect of prolonged exposure to isoamylol with base solution (5:1 v/v). Based on measured intracellular levels, fumarate (Fum) and trehalose-6-phosphate (T6P) were exemplified. The base solution consisted of acetone: ethanol = 1:1 (mol/mol). Prolonged exposure was achieved by leaving samples at − 30 °C +  0, + 5, and + 30 min before the centrifugation step. Samples were drawn from a culture at 60 h. Data were averages ± standard deviation of the three replicate samples. Each was analyzed in triplicate