TABLE 1.

Summary of global transcription patterns caused by treatment of S. pneumoniae R6 with sublethal concentrations of translation inhibitors in CDMa

Translation inhibitorConcn (μg/ml)bDoubling time (min)cGenes with change in transcript amt
Total no.No. with decreaseNo. with increase
Puromycin16123945242
Tetracycline0.251661288741
Chloramphenicol415415610353
Erythromycin0.121811389147
  • a Growth conditions and microarray analyses are described in Material and Methods.

  • b Drug concentrations were chosen to give 50% growth inhibition compared to control (DMSO) cultures (see Materials and Methods).

  • c The reported doubling times are averages from two to three independent experiments. The doubling time of S. pneumoniae R6 control cultures treated with the solvent (1% [vol/vol] DMSO) used to dissolve the antibiotics was ≈70 to 80 min.

  • d The number of genes whose transcript amounts showed relative changes ≥2-fold in at least two independent experiments are indicated (see Materials and Methods). Of the total number, genes whose transcript amounts increased or decreased are tabulated.