OSMOTIC-ADJUSTMENT IN THE CYANOBACTERIUM SPIRULINA-PLATENSIS - PRESENCE OF AN ALPHA-GLUCOSIDASE

Cell-free extracts of Spirulina platensis grown under a hypersaline condition showed substantial levels of in vitro alpha-D-glucosidase activities. The activity of this enzyme increased upon transfer to hyposaline medium. The increase in in vitro activity of the alpha-D-glucosidase in the down-NaCl-shock Cells was prevented by addition of an inhibitor of either RNA biosynthesis (streptomycin or methyl-purine), or protein biosynthesis (chloramphenicol). A possible involvement of the cyanobacterial alpha-D-glucosidase in the osmotic adjustement of S. platensis is discussed.