Distribution of transcripts in the five ρ_D classes. The degradation coefficient ρ_D was calculated for 2947 individual transcripts for the three growth rate comparisons (bars from left to right: 0.20 versus 0.10 h⁻¹, 0.40 versus 0.20 h⁻¹ and 0.63 versus 0.40 h⁻¹). Regulatory classes named I to V were defined according to the ρ_D value: ρ_D < 0, class I; 0 < ρ_D < 0.4, class II; 0.4 < ρ_D < 0.6, class III; 0.6 < ρ_D < 1, class IV and 1 < ρ_D, class V. The signification of the ρ_D classes is: I – Mainly transcriptional control with differences in degradation and transcription having opposite effects, II – Mainly transcriptional control with differences in degradation and transcription acting in the same direction, III – Control almost equally divided between degradation and transcription, with the two acting in the same direction, IV – Mainly degradational control with differences in degradation and transcription acting in the same direction, V – Mainly degradational control with differences in degradation and transcription acting in opposite directions.