PHYSIOLOGICAL-RESPONSES OF BACILLUS SPECIES TO CONCANAVALIN-A .2. EFFECT ON GROWTH, OXYGEN-UPTAKE, ENZYME-ACTIVITIES AND INTRACELLULAR CYCLIC GUANOSINE 3',5'-MONOPHOSPHATE LEVEL OF B-CEREUS ATCC-14579

  • 1 January 1984
    • journal article
    • research article
    • Vol. 39  (157-) , 137-150
Abstract
The effect of the mitogen concanavalin A (Con A) on growth and several physiological aspects of B. cereus ATCC 14579 was investigated. Con A at concentrations of 50-750 .mu.g/ml stimulated growth (the growth rate increased from 0.52/h to 0.97/h, and final yield increased by 2.3-fold over the control) of the bacterial cells. Con A-treated cells also increased their O2 uptake (1.6-fold increase when treated with 750 .mu.g/ml of Con A). The activities of the membrane-bound dehydrogenase and phosphatase increased by 1.75-fold and 2.1-fold, respectively, when treated with 500 .mu.g/ml of Con A. Only a 1-fold increase in .alpha.-glucosidase activity was observed when cells were treated with the same concentration of Con A. Con A at concentrations of 500-1000 .mu.g/ml stimulated the cellular synthesis of cGMP by 1-fold. Evidently, binding of Con A to the cell envelope led to increased synthesis of cGMP which might serve as an intracellular messenger for expression of the mitogenic signal of Con A. Since 50 mg/ml of .alpha.-methyl-D-mannopyranoside, a Con A inhibitor, reversed the stimulatory effect of Con A. The stimulatory action was apparently initiated by the specific binding of Con A molecules to the cell envelope. The stimulatory effect was Con A dosage dependent.

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