Osmoregulation in Acanthamoeba castellanii—III. Relations between dry weight, water, and inorganic ions, and control of the ionic levels

Polyamines in Acanthamoeba castellanii: presence of an unusually high, osmotically sensitive pool of 1,3-diaminopropane

High (15-25 mM) concentrations of 1,3-diaminopropane, a normally minor derivative of polyamine metabolism, have been observed in vegetative cells of Acanthamoeba castellanii. Trace amounts of a putative polyamine, which chromatographically behaved like norspermidine, were also found. The size of the intracellular pool of 1,3-diaminopropane was inversely related to the ambient osmolality and to the free amino acid levels during osmotic shock experiments. Due to its high concentration in A. castellanii, this diamine may be operative in ionic regulation during environmental stress. 1,3-diaminopropane may substitute for putrescine, a common diamine which was undetectable in A. castellanii.