Search

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.

In order to utilize the biomass of the polychaete Sabella spallanzanii Gmelin as a dietary supplement for fish nourishment, we conducted some experiences of rearing this worm in the Mediterranean Sea. A preliminary study on the growth of this species on suspended plastic nets was conducted in two sites of the Apulian coast with different trophic features. Data for the first 12 months show that S. spallanzanii reared in eutrophic conditions grows producing a biomass higher than the natural population. The acquired experience was afterward tested in a pilot plant located in the Mar Piccolo of Taranto, a eutrophic area where polychaetes were co-cultured with Mytilus galloprovincialis within a long-line farm. The slight mortality recorded during the first 2 months and quite negligible after 4 months, the high increase in volume and biomass of the reared polychaetes, especially at high density (70 individuals for each net), demonstrated the advantage of rearing S. spallanzanii in the pilot plant with low cost of production and high profit. If the acquired technology is applied to a medium farm containing up to 400 sectors, the biomass produced indeed might reach about 1.36 tons/year. In conclusion, on the basis of our results, we demonstrated the possibility to obtain high-value worm biomass coupled to mussel biomass in a completely non-fed culturing system without increasing, but presumably reducing the environmental impact due to mussel farming.

A study on macrobenthos of Acquatina Lake, a transitional water basin, was performed in order to evaluate its present status and detect any faunistic changes after the digging of a larger connection with the open sea that has improved the hydrological conditions. A total of 5029 individuals belonging to 51 taxa were collected. Molluscs were taxonomically the richest group, but polychaetes were the most abundant due to the high abundance of Heteromastus filiformis. The sites representing two extremes of the biotope in terms of both the salinity gradient and the distance from the sea had the most variable assemblages, while the central area showed a more homogeneous faunal composition. This was due to the different distribution patterns of molluscs and polychaetes: the former seemed to be more influenced by salinity, while the latter were also influenced by oxygen saturation. The comparison between the present and historical data showed the increase of polychaete diversity, the change in the dominant taxa (from Naineris laevigata to H. filiformis) and the disappearance of some opportunistic forms (e.g. Capitella capitata). Changes in the salinity gradient and the improvement of trophic conditions, possibly enhanced by biotic interactions (e.g. possible competition between the two capitellids H. filiformis and Notomastus latericeus), may have led the polychaete assemblage towards the new equilibrium. Un estudio del macrobentos del lago Acquatina; una cuenca de agua de transición; fue realizado para evaluar su estatus actual y detectar posibles cambios faunísticos después de una intervención humana reciente. Un total de 5029 individuos pertenecientes a 51 taxa fueron recolectados. Los moluscos fueron el grupo más rico; pero los poliquetos fueron el grupo numéricamente dominante debido a la abundancia de Heteromastus filiformis. Las zonas que representan los dos biotopos más extremos; en términos de salinidad y confinamiento; fueron las más variables en comparación con las áreas centrales más homogéneas. Este patrón se debe a la diferente distribución entre moluscos y poliquetos: los primeros parecían estar más influenciados por la salinidad; mientras que los segundos están influenciados; además; por los niveles de saturación de oxígeno. La comparación entre la composición actual de poliquetos y los datos históricos muestran un incremento de la diversidad; el cambio de las especies dominantes (de Naineris laevigata a H. filiformis); y la desaparición de algunas formas oportunistas (por ejemplo Capitella capitata). Cambios en el gradiente de salinidad y la mejora de las condiciones tróficas podrían dirigir la agrupación de poliquetos hacia un nuevo equilibrio; sin embargo algunas interacciones bióticas (por ejemplo la posible competición entre los capitéllidos H. filiformis y Notomastus latericeus) también podrían contribuir a explicar el patrón observado.

The polychaete Myxicola infundibulum (Renier) produces a large amount of dense mucus which forms a gelatinous envelope where the worm lives. In the present study we evaluated some of the physical-chemical properties of this matrix such as viscosity, osmolarity, electrical conductivity, and protein, carbohydrate and total lipid content The presence of an antibacterial lysozyme-like activity as well as the density of culturable bacteria at 22 degrees C and vibrios and associated macrofauna were also investigated. The water content of M. infundibulum mucus was 95 +/- 0.5%. By dry weight, 38 +/- 1.2% was protein, 2 +/- 021% was carbohydrate and only 3% was lipid. Most of the remainder of the dry weight (about 57%) was inorganic. The mucus of M. infundibulum exerted a lysozyme-like activity evidenced on Petri dishes inoculated with Micrococcus luteus cell walls with a diameter of lysis of 8.4 +/- 0.3 mm, corresponding to 1.15 mg ml(-1) of hen egg white lysozyme. Notwithstanding this high antibacterial activity, the mucous tubes of M. infundibulum contained a high density of culturable heterotrophic bacteria at 22 degrees C, of which presumptive culturable vibrios accounted for 4.6 +/- 0.2 x 10(3) CPU ml(-1). Moreover, tubes were found to be colonized by several specimens of the polychaete Lumbrineris cfr. latreilli. Therefore the mucus of M. infundibutum appears to provide defence against some bacteria and food supply for the growth of others, that in turn could be utilized by macrofaunal organisms. On account of these features this matrix represents an accessible and renewable resource that could repay further exploration from several points of view. (C) 2014 Elsevier B.V. All rights reserved.

Although mucus plays many different roles among marine invertebrates, relatively little is known about the link between biochemical structure and function. In the present study we focused on some physical and chemical properties of the polychaeteSabella spallanzanii's mucus such as viscosity, osmolarity, electrical conductivity, elemental composition, the protein and carbohydrate content, the total lipids and fatty acid composition, and polychlorinated biphenyls (PCBs) contamination. Moreover, an antimicrobial activity of the mucus was investigated. The water content ofS. spallanzaniimucus was 96.2±0.3%. By dry weight 26±1.2% was protein, 8±0.21% was carbohydrate and only 0.1% lipid, much of the remainder of the dry weight was inorganic (about 65.2%). The estimated PCBs content was −1. The mucus ofS. spallanzaniiexerted a natural lysozyme-like activity and producedin vitrothe growth inhibition ofVibrio anguillarum, Vibrio harveyi, Pseudomonas aeruginosaandCandida albicans.The findings from this study contribute to improve the limited knowledge available on the mucus composition in invertebrates and have implications for future investigations related to employment ofS. spallanzaniimucus as a source of compounds of pharmaceutical and marine technological interest.

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.

In several species mucus typically forms a slippery coating that performs many specialised roles including the defence against infection and protection for eggs. In the present study we focused on the mucus of the polychaete Sabella spallanzanii in order to ascertain its involvement in chemical defence and fertilization success. The observations were carried out over an annual cycle according to different phases of the reproductive cycle. Mucus of S. spallanzanii showed a natural lysozyme-like activity with a maximum at pH 6.0 and I = 0.175. This activity was present in all the sampling times except for January (T 4 ) which corresponds to the reproductive period of this species. The electrophoretic analysis revealed at least ten major protein bands, with molecular weights ranging from 16 to 90 kDa, and six minor components, with molecular weights ranging from 14 to 116 kDa. This pattern was reported all over the year except for the reproductive period when not only the lysozyme-like activity decreased but the number of protein bands was also reduced. During this period microscopical observations of the mucus indicated that only fertilised eggs enveloped in the mucus were released out of the tubes where the worms live. This supports previous hypothesis that fertilization does not occur in the water column but it takes place in the tube just after egg release ( in situ fertilization). This fertilization strategy, not involving egg dispersal in the water column, ensures a high success of fertilization. The mucus of S. spallanzanii therefore represents the ideal mean where eggs are released and fertilized as well as a compartment involved in defending the worms from bacterial attack serving as medium into which the antibacterial substances are exuded. The defensive role of lysozyme is important taking into account that this polychaete lives in eutrophic environments such as harbours where bacteria, including pathogens to man and marine organism, are abundant.