Bacteria and Anaerobic and Aerobic Growth Conditio...
R.capsulatus SB1003 was grown either photoheterotrophically or chemoheterotrophically as described9，10］.The photo-heterotrophically grown cells were cultured at 30℃and at a light intensity of 30 W/m2 in 15-ml screw-cap tubes.The tubes were filled completely to the top with malate-minimal RCV medium［i7］.The doubling time of cells under these conditions is about 3 h.The gyrase inhibitors novobiocin，coumermycin，nalidixic acid，and oxolinic acid were added when the cells were grown to midlogarithmic phase（5-7）×108 cells per ml）.The cells were harvested at various time points and used for pigment，chromatophore，and RNA preparation［9，10］.
For the experiments involving a shift from aerobic to photosynthetic growth，the aerobic growth was maintained by chemoheterotrophic culture（10 m lof medium in a 120-ml Erlenmeyer flask）on a Gyratory shaker（200 rpm）.Induction of the photosynthetic genes was performed by pouring the midlogarithmic-phase aerobic cells into 15-ml screw-cap tubes filled to the top and by culturing them under the anaerobic photosynthetic conditions.Novobiocin or coumermycin was immediately added to cell cultures after the shift from the aerobic to the anaerobic conditions.The cells were harvested after 3 h for pigment and RNA extraction.(https://www.daowen.com)
