The Incorporation of 35S-Labeled Sulfate into Carrageenan in Chondrus crispus

C. crispus was harvested during August, 1970 in the vicinity of Nobska Point, Cape Cod, Massachusetts and was held in flowing sea water until used, in no instance over 18 hr. Selected fronds, free of epiphytes, were cut into 0.1-g pieces, rinsed with sterile-filtered ASP,, medium (9) in which MgSO4 had been replaced with MgCl2, and transferred to a sterile flask containing sterile medium of the same composition supplemented with trace elements in the form of salts other than sulfate. The chemical and radioactive level of sulfate in each flask was determined by appropriate additions of Na2'SO4 and carrier-free H2oSO4. Traces of sulfate present in the medium prior to addition of carrier-free H2'3SO4 was estimated as 0.1