FIG. 1.

Adaptation of B. subtilis JH642 to cold shock in minimal medium with different amino acids. After inoculation (OD₆₀₀, 0.05) from an overnight culture in the same medium, the cells were grown at 37°C to an OD₆₀₀ of 0.45 and subjected to cold shock (15°C). Amino acids in 100 μM final concentration were added 5 min before the cold shock. Cell density and growth were monitored by measuring the OD₆₀₀. A cumulative graph of three independent experiments is shown. ■, addition of 0.02% casamino acids; ▴, 100 μM isoleucine; ⧫, 100 μM threonine; ▾, 100 μM leucine; ●, 100 μM aspartate; □, no addition.