Superoxide radical production by sponges Sycon sp

Using the catechol Tiron as an O −⋅ 2 scavenger, we showed that sea sponges ( Sycon sp.) produce superoxide radicals in sea water at a high rate without any stimuli added. The rate of O −⋅ 2 outflow from sponges to their water surroundings reaches a value of 0.5 nmol/min per sponge at pH 6.5. The generation of O −⋅ 2 was inhibited by Cu,Zn-superoxide dismutase, and restored by the addition of KCN. We also confirmed the abiotic production of O −⋅ 2 in sea water, detected earlier with a different method by Petasne and Zika [Nature 325 (1987) 516–518].