ISOLATION OF OSCILLATORIA-SPONGELIAE, THE FILAMENTOUS CYANOBACTERIAL SYMBIONT OF THE MARINE SPONGE DYSIDEA-HERBACEA

The tropical marine sponge Dysidea herbacea (Keller) (Dictyoceratidae: Dysideidae) is always found associated with the filamentous cyanobact erium (blue-green alga) Oscillatoria spongeliae (Schulze) Hauck (Cyano phyceae: Oscillatoriaceae), which occurs abundantly throughout the spo nge mesohyl. Intact, metabolically active, trichomes of O. spongeliae were isolated from the sponge by chopping the sponge tissue with a raz or blade and squeezing the trichomes into a seawater-based medium cont aining polyvinylpyrrolidone, bovine serum albumin, dithiothreitol, gly cerol, KC1 and Na2CO3. The isolated cyanobacteria were concentrated by centrifugation and then washed several times in fresh medium. The iso lated O. spongeliae have photosynthetic rates which are similar to the intact sponge-alga association for periods of at least 6 h after isol ation. Addition of sponge homogenate to the isolated cyanobacteria cau ses rapid cell lysis.