PERMEABILITY OF AZOTOBACTER TO SUCCINATE AND MALATE,

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Abstract
Adaptation of sucrose-grown Azotobacter agilis to succinate and malate was inhibited if the cells were washed in distilled water; the normal adaptive lag period of 1/2 hr. was extended beyond 2 hr. A factor, which was found in the washings and was identified as glucose or a glucose polymer, could be added back to washed cells to reestablish the 1/2-hr. lag period. Although unadapted cells were unable to oxidize succinate immediately, cell-free extracts from these cells possessed succinic de-hydrogenase and succinic oxidase activities. Succinic dehydrogenase and succinic oxidase activities in extracts from unadapted cells and from succinate-adapted cells were compared, and the specific activities were the same. Succinate adaptation does not involve a change in the succinate oxidizing capacity, indicating that succinate permeation is probably restricted in unadapted cells. Adaptation to succinate was prevented if either deoxyribonucleic acid, ribonucleic acid, or protein synthesis was inhibited by such agents as UV, proflavin, 8-azaguanine, 5,6-dichloro-1-of-D-ribofuranosylbenzimidazole, chloramphenicol, or p-fluorophenylalanine; succinate oxidation was not inhibited after adaptation was complete. Sodium azide and 2,4-dinitrophenol were used to demonstrate that permeation of succinate requires an endogenous source of energy. No significant effect was observed when whole cells were used, but protoplasts prepared from succinate-adapted cells were inhibited 30 and 80% by 10-3 [image] azide and 10-4 [image] dinitrophenol respectively.