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Fishery and Sea Resources4 Discussion and conclusionsThe revaluation of natural products is notsurprising since secondary metabolites arethe adaptive product of the long-term evolutionof competitive interactions betweenorganisms. By contrast, in the combinatorychemical synthesis the possibility tosynthesize a biologically active product ismerely probabilistic. Our results indicatethat the target marine organisms are suitablefor potential exploitation in pharmaceuticsand dietetics on account of their observedinteresting antibacterial activities aswell as their proteo-lipidic profiles. Indeedthe finding of a lysozyme-like antibacterialactivity in the mucus of S. spallanzaniias well as in the nematocysts of thestudied cnidarians have implications for futureinvestigations related to the employmentof these matrices as a source of compoundsof pharmaceutical interest. As regardspharmaceuticals, we have to considerthat by now the use of antibiotics isa common routine in the cure of bacterialinfections. However, the increasing developmentof bacterial resistance to traditionalantibiotics, even to cocktails of differentproducts, has reached alarming levels,thus necessitating the strong need todevelop new antimicrobial agents. Furthermore,in these last years, the occurrence offungal infections in the humans is greatlyincreased due to the rise of people affectedby immunodeficiency. Lysozyme exhibitsantimicrobial activity against different microorganisms,and it was chosen recentlyas a model protein to develop more potentbactericidal agents with broader antimicrobialspecificity. Several strategies are attemptingto convert lysozyme to be activein killing Gram-negative bacteria otherthan Gram- positive bacteria thus introducing,for the first time, a new conceptualutilization of lysozyme which would bean important contribution for medicine andmodern biotechnology [17]. Thus, S. spallanzaniimucus and nematocyst extracts ofthe studied cnidarians provide an accessible,renewable resource that could rewardwider exploration. Moreover, the isolatedbioactive metabolites could constitute newleads on which the research of new pharmacologicallyactive compounds throughsynthetic way should be based. The fattyacid profiles of the examined macroalgaeshowed that palmitic acid methyl ester(16:0) was the predominant saturatedfatty acid. Since the palmitic acid representsthe main component of fatty acids, itis presumably responsible for the antibacterialactivity observed in the target algalspecies. In several studies, indeed, palmiticacid has been reported to be the major antibacterialcompound in a mixture of fattyacids from other algal species. The abilityof fatty acids to interfere with bacterialgrowth and survival has been knownfor several decades [18]. The antibacterialeffects of fatty acids are frequentlyobserved during bioassay-guided fractionationof extracts from a variety of organisms[19, 20, 18]. Their broad spectrumof activity, non-specific mode of actionand safety makes them attractive asantibacterial agents for various applicationsin medicine, agriculture, aquacultureand food preservation, especially wherethe use of conventional antibiotics is undesirableor prohibited. In this framework,an interesting issue of the presentproject is that the lipidic extract of C. barbata,G. longissima and C. rupestris inhibitedthe growth of several Vibrio species,which include some aquaculture-relevantpathogens. These results are relevant con-2050