ABSTRACT
In the marine environment, many organisms, including invertebrates, secrete mucosal matrices with different properties in relation to the composition, structure, and evolutionary function. The mucus of many invertebrates offers mechanical protection but also contains specific compounds making the animal poisonous, distasteful or irritating, or a combination of these features. In particular, some invertebrates could lace their mucus with antibiotic molecules when it is more advantageous for them to inhibit bacterial attack. In the present chapter, mucus antibacterial activity in some polychaete, echinoderm, and cnidarian species is reported and discussed. Moreover, the role of mucus as food source for bacteria playing a role in the structuring of specific beneficial microbial communities is also analyzed. Particular attention is paid to the association of vibrios with the polychaete Myxicola infundibulum explained in function of the Vibrio species feeding activity on the mucus. In addition, apart from the feeding activity, the other specific adaptations developed by several mucus associated bacteria living in the microenvironment crated by the invertebrate hosts are examined. The case studies reported indicate that mucus constitutes a matrix requiring further investigation from different points of view.
