NUTRITION OF LEPTOSPIRA POMONA III

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Abstract
Johnson, R. C. (Fort Detrick, Frederick, Md.) and N. D. Gary. Nutrition of Leptospira pomona. III. Calcium, magnesium, and potassium requirements. J. Bacteriol. 85:983–985. 1963.—The cation requirements for Leptospira pomona Wickard were investigated employing a basal medium prepared with 10% deionized rabbit serum and containing 10−3m NH4Cl, 5 μg/ml thiamine, and 0.01 m Na2HPO4 buffer (pH 7.4). Rabbit serum was deionized by passage through a column of Amberlite IRC-50 resin. This basal medium did not support growth when either Ca++ or Mg++ was added to it. However, when both Ca++ (3 × 10−5m) and Mg++ (5 × 10−6m) were present, growth was obtained. Although an absolute requirement for K+ could not be demonstrated, an increase in the amount of growth did occur if K+ (5 × 10−5m) was incorporated in addition to Ca++ and Mg++. When adequate concentrations of Ca++ and K+ were present with a limiting concentration of Mg++ (less than 5 × 10−7m), filamentous cells were observed.