EFFECTS OF MG2-PLATENSIS, A CYANOBACTERIUM( ON THE GROWTH AND DNASE ACTIVITY OF SPIRULINA)

To investigate the methodology to inhibit DNase activity in the cyanob acterium Spirulina, the effects of Mg2+ on the growth and DNase activi ty of Spirulina platensis strain SSP-14 were studied. The results indi cated that strain SSP-14 could keep growing, but much slower, when ino culation and cultivation were done twice in Mg2+/free Zarrouk medium; and the activity of both intracellular and extracellular DNases was al most completely inhibited. This manipulation could efficiently remove the high-level activity of DNases which frequently exist in Spirulina and block foreign genes from being introduced. It is recommended that the technique be applied for genetic transformations of this alga. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.