Sodium Requirement for cAMP-Induced Spirulina Mat Formation

Abstract

The presence of NaCl was essential for cAMP-induced cell aggregation leading to a mat formation in the cyanobacterium Spirulina platensis. The most effective concentration for the mat formation was 0.25 M and higher concentrations were inhibitory. The mat formation occurred under a physiological pH of 7 to 9. Li⁺ and K⁺ were less effective than Na⁺ and divalent cations such as Ca²⁺ or Mg²⁺ showed no effect on the mat formation. It was suggested that Na⁺ enabled the mat formation by supplying energy to cells for aggregation.