Effect of low-dose ultrasonic treatment on phystological variables inAnabaenaflos-aquae andSelenastrumcapricornutum

Cell protein content in two species of cultured algaeAnabaenaflos-aquae andSelenastrumcapricornutum, was markedly enhanced by low-dose, short-duration ultrasonic treatment. Chlorophylla levels and14C-bicarbonate uptake rates were not affected by ultrasonic treatment in either species. Ultrasonically-activatedAnabaena cultures placed in media deficient in nitrogen and phosphorus produced more biomass per unit time, exhibited less cell-surface alkaline phosphatase activity per cell, and had a higher heterocyst frequency than non-sonicated, nutrient-deficient cultures. In contrast, sonicated, nutrient-deficientSelenastrum cultures grew more slowly and had higher alkaline phosphatase activity than non-sonicated variants. Collectively, the data suggest that key metabolic variables may be altered by ultrasonic treatment in algal cultures and that the magnitude and direction of change may be species-specific.