TABLE 1.

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

Translation inhibitor	Concn (μg/ml)b	Doubling time (min)c	Genes with change in transcript amt
			Total no.	No. with decrease	No. with increase
Puromycin	16	123	94	52	42
Tetracycline	0.25	166	128	87	41
Chloramphenicol	4	154	156	103	53
Erythromycin	0.12	181	138	91	47

^aGrowth conditions and microarray analyses are described in Material and Methods.

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

^cThe 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.

^dThe 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.