Example 4
Anabaena floc-aquae (Ana) was cultured in Gorham's media supplemented with BG-11 solution (Sigma, St. Louis, Mo.) and 10 mM NaHCO3 at 25° C., 100 rpm shaking and 1% CO2 under a 14 h light cycle and 10 h dark cycle. Once confluency was reached, the cultures were transferred to sterile separating funnels and the buoyant cells were allowed to float to the top and separate from the spent media over a 48 h period. Ana GVs were harvested by hypertonic lysis of the buoyant cells with 500 mM sorbitol and 10% Solulyse (Genlantis, San Diego, Calif.). Purification was done by repeated centrifugally assisted floatation followed by resuspension in 1×PBS (Corning, Union City, Calif.). GV concentration was determined by pressure-sensitive OD measurements at 500 nm (ODPS,500). Pre-collapsed GVs prepared by application of hydrostatic pressure in a capped syringe were used as the blank.