REVERSIBLE INACTIVATION OF THE TOXICITY AND HEMOLYTIC ACTIVITY OF TYPHUS RICKETTSIAE BY STARVATION

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Abstract
When purified preparations of the E strain of typhus rickettsiae are incubated for several hours at 36[degree]C in the absence of substrate, hemolytic activity and toxicity are lost. The loss can be prevented by addition of glutamate, pyruvate, or adenosine triphosphate (ATP). Subsequent incubation of the starved organisms with glutamate at 30[degree]C leads to partial or complete recovery of toxicity and hemolytic activity. No other substance can substitute for glutamate in bringing about recovery, though ATP or adenylic acid, added with glutamate, can sometimes increase the extent of recovery. Analysis of the ATP content of the rickettsiae during the starvation and recovery process indicates that the ATP level falls to zero during starvation and rises again on addition of glutamate. Anything that diminishes the final ATP level also inhibits recovery. However when glutamate is added at 35[degree]C instead of at 30[degree]C, the rickettsiae show much less recovery of toxicity and of hemolytic activity, though they are capable of even more active oxygen uptake and phosphorylation. It appears therefore that some process in addition to phosphorylation is required for recovery.