The Mucus of Actinia equina (Anthozoa, Cnidaria): An Unexplored Resource for Potential Applicative Purposes.

The mucus produced by many marine organisms is a complex mixture of proteins and polysaccharides forming a weak watery gel. It is essential for vital processes including locomotion, navigation, structural support, heterotrophic feeding and defence against a multitude of environmental stresses, predators, parasites, and pathogens. In the present study we focused on mucus produced by a benthic cnidarian, the sea anemone Actinia equina (Linnaeus, 1758) for preventing burial by excess sedimentation and for protection. We investigated some of the physico-chemical properties of this matrix such as viscosity, osmolarity, electrical conductivity, protein, carbohydrate, and total lipid contents. Some biological activities such as hemolytic, cytotoxic, and antibacterial lysozyme-like activities were also studied. The A. equina mucus is mainly composed by water (96.2% ± 0.3%), whereas its dry weight is made of 24.2% ± 1.3% proteins and 7.8% ± 0.2% carbohydrates, with the smallest and largest components referable to lipids (0.9%) and inorganic matter (67.1%). The A. equina mucus matrix exhibited hemolytic activity on rabbit erythrocytes, cytotoxic activity against the tumor cell line K562 (human erythromyeloblastoid leukemia) and antibacterial lysozyme-like activity. The findings from this study improve the available information on the mucus composition in invertebrates and have implications for future investigations related to exploitation of A. equina and other sea anemones' mucus as a source of bioactive compounds of high pharmaceutical and biotechnological interest.

Bioremediation of bacteria in aquaculture waste using the polychaete Sabella spallanzanii.

The excessive release of bacterial pathogens from animal waste into the aquaculture environment has become a major concern for the aquaculture industry. The biological filtration by macroinvertebrates contributes to water purification as a result of the bacterioplankton removal from the water. The filter-feeder polychaete Sabella spallanzanii is known for its ability to accumulate bacteria from the marine environment. In the present study we evaluated the survival, growth and capability of this species to remove several bacterial groups from aquaculture waste in order to ascertain its employment as bioremediator in a farming scenario coupled with the conversion of the wastes into polychaete protein-rich biomass of potentially marketable value. In comparison to other technologies, the employment of S. spallanzanii in waste treatment represents a more attractive option to reduce bacterial loads.