First Insights into the Chemical Composition of the Mucus of the Sponge Haliclona viscosa Isolated from Irish Marine Waters

Mucus secretions of marine invertebrates, such as sponges, corals, worms perform important functions in their lifetime due to their unique biochemical and physical properties. Mucus generally consists of (glyco) proteins (mucins) and polysaccharides. The viscoelastic, adhesive, antimicrobial and other properties of the mucus may have potential biomedical applications. Among the several sponges screened for mucus production from Irish waters, Haliclona viscosa was one of the promising candidate identified in the study. Earlier reports of H. viscosa revealed more than thirty structurally dierent polymeric 3-alkyl pyridinium salts (poly-APS 3-APS) with a wide range of biological activities. Most of the previous studies employed organic solvents and or the precipitation of aqueous extract using organic solvents for the isolation of poly-APS. However, due to its high water solubility and also to characterize other water-soluble macromolecules (proteins glycoproteins), the present study was undertaken. The aqueous extract (hand squeezed, after centrifugation at 10,000 rpm for 1 hr at 4 C) of H. viscosa was subjected to preparative ultracentrifugation followed by Polyacrylamide Gel Electrophoresis (PAGE) and Nuclear Magnetic Resonance (NMR) spectroscopic studies. Ultracentrifugation yielded four fractions at various densities (1.00, 1.07, 1.13 and 1.20 g mL). Based on NMR, fraction 1 and 2 confirms the presence of 3-APS and most of the proteins were concentrated in the fraction three according to electrophoretic separation. Fraction four was devoid of 3-APS and contained traces of proteins. Further work is under progress to characterize the poly-APS, proteins glycoproteins by Dynamic Light Scattering (DLS), Liquid chromatography-mass spectrometry (LC-MS) based proteomics.