Biomarkers in marine sponges: acetylcholinesterase in the sponge Cliona celata

Sponges, ubiquitously occurring organisms, have many characteristics that indicate their potential as biomonitors. Since it is very important to find the most wide range of organisms that can act as early warners of pollution, we investigated the presence of the biomarker acetylcholinesterase in the cosmopolitan sponge Cliona celata Grant, 1826. Specimens of C. celata were collected from pre-selected sites along the western coast of Iberian Peninsula considered undisturbed in terms of pollution, although some anthropogenic activities may occur. A standard analytical method was used – production of the anion 5-thio-2-nitrobenzoate for the determination of acetylcholinesterase. Our goal was to check the presence of this enzyme in this particular sponge, to validate the method used for these organisms, to determine the normal interval range of acetylcholinesterase activity and to check for eventual differences in the collection sites. Acetylcholinesterase activity was detected in all samples with two exceptions one from Arrábida and another from Berlengas, both from the Portuguese coast. The mean value for the remaining set was 2.87x10-8 U/ mg prot /g of fresh sponge and the variation interval was (0-11.0×10-8 U/ mg prot /g of fresh sponge). No significant differences have been found between collection sites but the samples preserved for a longer time displayed smaller values.