MODULATION OF 2'-5'OLIGOADENYLATE SYNTHETASE BY ENVIRONMENTAL-STRESS IN THE MARINE SPONGE GEODIA-CYDONIUM

Recently we established the presence of relatively high amounts of 2'- 5'oligoadenylates (2'-5'A) and 2'-5'oligoadenylate synthetase (2'-5'A synthetase) in the marine sponge Geodia cydonium. Here we determined b y applying radioimmunoassay and high-performance liquid chromatographi cal methods that the concentration of 2'-5'A and the activity of 2'-5' A synthetase change following exposure of G. cydonium tissue to enviro nmental stress. The 2'-5'A content and the activity of 2'-5'A syntheta se, present in crude sponge extract, increase by up to three fold afte r treating sponge cubes for 2 h with natural stressors including heat shock (26 degrees C), cold shock (6 degrees C), pH shock (pH 6), and h ypertonic shock and subsequent incubation for 18 h under ambient condi tions (16 degrees C). No response was observed after exposure of spong es to an alkaline (pH 10) or hypotonic environment. Similar changes ha ve been found for the expression of heat shock protein HSP70 in G. cyd onium. These results show that 2'-5'A in sponges may be useful as a no vel biomarker for environmental monitoring.