|Application:||Gene expression microarray analysis|
|Number of samples:||56|
|Release date:||Jul 31 2007|
|Last update date:||Jan 15 2017|
|Dataset link||RNA expression data from Halobacterium NRC-1 in response to oxic/anoxic transitions, initial experiment|
Halobacterium sp. NRC-1 (ATCC700922) was routinely grown in complex medium (CM; 250g/L NaCl, 20g/L MgSO4.7H2O, 3g/L sodium citrate, 2g/L KCl, 10g/L peptone) at 37ºC under full-spectrum white light. For turbidostat experiments, starter cultures of NRC-1 were inoculated into 2L of CM in a 3.0 L vessel (5-10% inoculum) and grown to mid-logarithmic phase (OD600 ~ 0.5) in batch mode in a BioFlo100 modular bench top fermentor (New Brunswick Scientific, Edison, NJ) at 300 – 500 rpm, pH 7.0. Prior to each experiment, an oxygen sensor (model InPro 6000, Mettler Toledo, Columbus, OH) was calibrated to 100% oxygen at 1200rpm and sparging with 3.2 VVM of air. These conditions were approximately equivalent to oxygen saturation in CM medium, which is 1.6 mg/L (~5uM). Once the culture reached mid-logarithmic phase, the oxygen level was rapidly decreased to 0.8-4.8% within 10 minutes (achieved by turning off airflow and reducing agitation to 250 rpm), and allowed to equilibrate for 12 h prior to the start of sampling. The flow rate was zero during low oxygen conditions. The oxygen concentration in the culture was then rapidly increased to approximately 90-95% (achieved by agitating at 1200 rpm and sparging the medium with 3.2 VVM of air) and sampling commenced and continued at the times indicated in the Sample records. The culture was subsequently kept in active growth at a flow rate of approximately 2.25 ml/min (specific growth rate ~0.1/hr) for 6hr. Cultures were then rapidly shifted (within 10 minutes) back to low oxygen for 6hr, and then finally back to high oxygen for 30 min. During these perturbations, all other parameters were kept constant (pH 7.2-7.3, 37ºC, ambient light, O.D.600~0.5-6.5). Each culture sample was split in half, one half being used for RNA extraction and the other for protein preparation. Samples were removed from the turbidostat according to the times indicated in the titles of the Sample records.