Development of nitric oxide and nitric oxide synthase as ecotoxicological biomarkers in the tropical marine environment

The enzyme nitric oxide synthase (NOS) catalyses reactions that result in the generation of nitric oxide (NO), a multipotent signal molecule. We have begun to characterise the activity of NOS found in the host tissue of the symbiotic tropical/sub-tropical anemone Aiptasia pallida, and have monitored changes in the activity of this enzyme under different environmental conditions. Our characterisation studies indicate that the NOS activity from Aiptasia is similar to activities from other organisms in terms of cellular localisation, cofactor requirements, and inhibition profiles. Our environmental experiments indicate that: (1) the incubation of whole animals at temperatures representative of the highest and lowest extremes to which the Bermuda population would be exposed results in an NOS activity reduction relative to animals maintained at the control temperature of 25 °C; and (2) treatment with copper produces variable changes in NOS activity relative to untreated controls.