Stability of bacterial messenger RNA in mesophiles and thermophiles

The decay of [3H]uridine-labeled mRNA was measured in the mesophile, Bacillus licheniformis (grown at 37 degrees C and 46 degrees C), and in the thermophile, Bacillus stearothermophilus (grown at 46 degrees C and 55 degrees C). For each organism, the half-life of the mRNA decreased as the growth temperature was increased. The stability index (half-life of mRNA/doubling time of cells), however, was remarkably constant for each organism regardless of the growth temperature. It is concluded that these results support the concept that kinetic considerations play a significant role in the explanation of thermophily.