V. THE EFFECT OF TEMPERATURE ON THE TERRAMYCIN-RESISTANT AND PHAGE-PRODUCING CELLS OF BACILLUS MEGATHERIUM CULTURES

John H. Northrop ¹ and With the Technical Assistance of Marie King

¹ From the Laboratory of The Rockefeller Institute, Department of Bacteriology, University of California, Berkeley

The growth rates, the mutation frequency rate constants of the terramycin-resistant cells, the burst size of the phage-producing cells, and the ratio of phage to cells all have a temperature coefficient of about 2 from 20 to 35° (µ = 9 x 10³ calories), with a maximum at 40°.

The mutation frequency rate constant (or time rate constant) of the phage-producing cells increases from 20 to 45° with a temperature coefficient of about 3 (µ = 2 to 3 x 10⁴ cal.).

The change in the values for the growth rate, mutation rate, and cell volume occurs in less than 1 hour, after the temperature is changed. The value for the burst size of phage-producing cells changes for 3 to 4 hours.

Prolonged growth of megatherium 899 at 48 to 50° results in the production of C + S phage, in place of T. Returning the culture to 25° results in the production of small T phage.

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