Nitric oxide (NO) is an important cell signaling molecule involved in immune responses, vasodilation, apoptosis, and several other secondary functions. Nitric oxide has been detected in living cultures of Emiliania huxleyi, a marine phytoplankton, in seawater using the Liposome Encapsulated Spin Trap (LEST) method. However, the minimum steady state concentration of NO required to detect the presence of NO is not known. Testing the limits of detection of LEST in cultures of E. huxleyi can provide insight into the source and function of nitric oxide. NOC-5, a known chemical source of NO, is added to representative samples of seawater with and without E. huxleyi, and the amount of NO captured by LEST is measured by Electron Paramagnetic Resonance (EPR) spectroscopy. Initial experimentation showed that the concentration of NO captured by LEST was significantly lower than the amount of NO expected to be produced by NOC-5. Possible activity of NO with systemically present superoxide could be responsible for decreasing available NO to be captured. To reduce the possibility of superoxide side reactions, a superoxide dismutase analogue, TEMPOL, was added. TEMPOL reacts with present superoxide to produce hydrogen peroxide, which reacts with NO far more slowly than superoxide. Samples with TEMPOL present produced higher concentrations of spin-trapped NO.

Testing the limits of NO detection with liposome encapsulated spin trap

255th National Meeting (2018)

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