COLD-SHOCK RESPONSE OF PROTEIN, RNA, DNA AND PHOSPHOLIPID-SYNTHESIS IN BACILLUS-SUBTILIS

A temperature shift-down (from 40 to 20 degrees C) stopped the growth of Bacillus subtilis for 80 min and profoundly perturbed the total rat es of macromolecular synthesis. Protein synthesis was abolished for 80 min and recovered after this period in parallel with the growth. RNA synthesis was reduced to a minimum level for 150 min; afterwards, tran scription accelerated to a new steady-state level. The rate of DNA syn thesis was first reduced to 20 % (for 80 min), than it exhibited an ad ditional drop after growth recovery. In contrast, the phospholipid syn thesis reached immediately after a temperature shift-down a new equili brium rate at 20 degrees C, modulating dramatically the polar head gro up composition. This behavior suggests an efficient cold adaptation of bacterial membrane structure.