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Four bacterial strains belonging to the genera Vibrio, Pseudoalteromonas and Photobacterium were isolated from the marine sponges Dysidea avara and Geodia cynodium. A Bacillus strain was isolated from Ircinia variabilis. A screening of molecules involved in quorum sensing (QS) was carried out by TLC-overlay and a new "plate T-streak" test. To analyze quorum quenching (QQ), a plate T-streak was performed with Chromobacterium violaceum. Strains of Vibrio isolated from both marine sponges and a strain of Photobacterium isolated from G. cynodium, activated QS bioreporters. A strain of Pseudoalteromonas isolated from D. avara showed QQ activity. Finally, it is reported that cyclic dipeptides isolated from strains of Vibrio sp. and Bacillus sp. (isolated from D. avara and I. variabilis, respectively) were involved in the QS mechanism. The simultaneous presence of bacteria that showed contrasting responses in bioassays for QS signal molecule synthesis in marine sponges could add an interesting dimension to the signalling interactions which may be happening in sponges.

Among plants, the Lycopersicon esculentum (Solanaceae) is the most important for its beneficial effects on health. Several epidemiological studies have shown the benefits of tomato consumption in the cancer and cardiovascular disease prevention. Tomato products constitute the major source of lycopene, the most potent antioxidant among carotenoids in vitro. In tomatoes leaves are also present many secondary metabolites including phenolic compounds, phytoalexins, protease inhibitors and glycoalkaloids who protect against adverse effects of hosts including fungi, bacteria, viruses, and insects and are involved in host-plant resistance. In this work we evaluated the antiproliferative activity of tomato leaves extract (var. Paul Robenson) in vitro.

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Marine sponges have been intensively studied by organic chemists, biologists and pharmacologists during last 60 years, due to great biodiversity of their secondary metabolites. A couple of very promising bioactivities of these compounds have been reported. Indeed, some of these metabolites are considered as the leads for the future drugs targeting tumours, viral and bacterial diseases, malaria and inflammations. Herein we briefly report key bioactivities of avarol, the main secondary metabolite of the marine sponge Dysidea avara (Schmidt, 1862).