Results New isolated strains were most closely related to Micrococcus sp., Bacillus aquimaris, Paracoccus sp. and Oceanobacillus sp. All EE were active against some bacteria +1 BE displayed activity against one Antarctic bacterial strain Strain BAC03 was resistant to antimicrobial agents of all bryozoan species Table 1. Antimicrobial activity of ether extracts of Antarctic bryozoans. Level: weak inhibition (0-1 mm, +), moderate inhibition (>1 to 3 mm, ++), strong inhibition (>3 to 7 mm, +++) and very strong inhibition (>7 to 15 mm, ++++). Blank space = inactive (Lippert et al. 2003) . Introduction The Antarctic continental shelves, with a relatively stable environment below the limit of ice scour and anchor ice, are characterized by the presence of a high diversity and abundance of sessile suspension feeders (Dayton et al. 1974). This stability leads to these communities being mainly influenced by biotic interactions, favouring the evolution of chemical defenses (Avila et al. 2008; McClintock et al. 2010). Among these benthic organisms, bryozoans are clearly an important component of Antarctic biodiversity (De Broyer et al. 2011). Especially, cheilostome bryozoans, the most successful living order of bryozoans, have developed during evolution a wide diversity of physical (e.g. avicularia or spines) and chemical mechanisms (natural products) used for different roles, such as defense against predators and prevention of epibionts’ settlement (fouling; Winston 1986; Iyengar and Harvell 2002; Lopanik et al. 2006; Figuerola et al. 2013, 2014). Material and methods Discussion • This study is one of the first attempts to investigate the antimicrobial activity of common and abundant Antarctic bryozoan species in the proximities of the South Shetland Islands, the Antarctic Peninsula and the Weddell Sea against sympatric bacteria (Lebar et al. 2007; Sharp et al. 2007). • Our study suggests that antimicrobial activity is common among Antarctic bryozoans and it is selective: - confirms the previous hypothesis that these bryozoan species are particularly active (e.g. Colon-Urban et al. 1985; Taboada et al. 2013; Figuerola et al. 2013b, 2014). - larger presence of lipophilic antimicrobial compounds detected. • Antimicrobial activity could be a potential successful strategy against bacteria and, therefore, a defense against subsequent macro-foulers and predators (Lippert et al. 2003). • The lack of (or low) activity recorded previously in bryozoan species against some Antarctic bacterial strains might be explained as a result of co-evolution (Lippert et al. 2003). • Different intra/interespecific patterns of antimicrobial activity were found, suggesting that Antarctic bryozoan species may produce diverse bioactive metabolites. • Our results confirm that marine natural products from bryozoans may be good sources of useful antimicrobial compounds (Tadesse 2010). References. Avila, C., Iken, K., Fontana, A., Gimino, G. 2000. J Exp Biol Ecol 252:27–44; Dayton P.K., Robillia, G.A., Paine, R.T., Dayton, L.B. 1974. Ecol Monog 44:105–128; De Broyer C, Danis B, 64 SCAR-MarBIN Taxonomic Editors. 2011. Deep Sea Res Part II Top Stud Oceanogr 58:5–17. Figuerola, B., Núñez-Pons, L., Moles, J., Avila, C. 2013. Naturwissenschaften 100:1069–1081. Figuerola, B., Núñez-Pons, L., Monleón-Getino, T., Avila, C. 2014. Polar Biol 37:1017–1030. Iyengar, E.V., Harvell, C.D. 2002. Mar Ecol Prog Ser 225:205–218. Iken, K., Avila, C., Fontana, A., Gavagnin, M. 2002. Mar Biol 141:101–109. Lebar, M.F., Heimbegner, J.L., Baker, B.J. 2007. Nat Prod Rep. 24(4):774-797. Lopanik, N.B., Targett, N.M., Lindquist, N. 2006. Mar Ecol Prog Ser 327:183–191. McClintock, J.B., Amsler, C.D., Baker, B.J. 2010. Integr Comp Biol 50:967–980. Sharp, J.H., Winson, M.K. and Porter, J.S. 2007. Nat Prod Rep 24: 659-673. Taboada, T., Núñez-Pons, L., Avila, C. 2013. Polar Biol 36:13–25. Tadesse, M. 2010. PhD thesis, University of Tromsø, Tromsø. Winston, J.E. 1986. Mar Ecol 7:193–199. Winston, J. E. & Bernheimer, A. W. 1986. J Nat Hist, 20, 369−374. Acknowledgements. We are thankful to L. Núñez, J. Moles, S. Taboada, J. Cristobo, A. Riesgo and M. Bas for their laboratory support. In this work we used the extracts from previous projects (ECOQUIM projects), for this reason we want to thank W. Arntz, and the R/V Polarstern and the BIO-Hespérides crews. We would like to thank as well the Unidad de Tecnología Marina (UTM) and the crew of Las Palmas vessel for all their logistic support. Special thanks are also given to the “Gabriel de Castilla BAE” crew for their help. This research was developed in the frame of the ACTIQUIM I and II projects (CGL2007-65453/ANT, CTM2010-17415/ANT) with the financial support of the Spanish Government. L. Sala-Comorera and C. Angulo are recipients of FPU and FPI grants from the Spanish Government, respectively (FPU12/00614, BES-2010-035521). An$microbial ac$vity of Antarc$c bryozoans in a clinical and ecological perspec$ve Blanca Figuerola 1* , Laura Sala‐Comorera 2 , Carlos Angulo‐Preckler 1 , Jennifer Vázquez 1 , M. Jesús Montes 3 , CrisEna García‐Aljaro 2 , Elena Mercadé 3 , Anicet R. Blanch 2 and Conxita Avila 1 Department of Animal Biology (Invertebrates) and Biodiversity Research Ins$tute (IrBIO), Faculty of Biology, University of Barcelona, Barcelona, Catalunya, Spain 1 ; Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Catalunya, Spain 2 ; Department of Health Microbiology and Parasitology, Faculty of Pharmacy, University of Barcelona, Barcelona, Catalunya, Spain 3 *Email address: *bfiguerola@gmail.com www.actiquim.cat Klugella echinata Nematoflustra flagellata Melicerita obliqua Isosecuriflustra tenuis A B C D Chemical extractions Extraction with acetone partitioned into diethyl ether fraction (repeated three times) evaporation of organic solvents under reduced pressure dry diethyl ether dry butanolic extracts an aqueous residue. The detailed description of the extraction procedure has been reported elsewhere (Avila et al. 2000; Iken et al. 2002). Collection samples and identification Bryozoan samples were collected in the Eastern Weddell Sea (Antarctica) (273,6-351,6 m) during the ANT XXI/2 (Nov. 2003-Jan. 2004) on board the R/V Polarstern (Table1). A small part of each sample: fixed in 70% ethanol (for further taxonomical identification) The remaining material: frozen at -20°C Test: A: disc without any additive (- control) B: disc with the solvent (methanol, - control) C: disc with chloramphenicol (+ control) D: disc with EE or BE The aim of the present study is to assess the role and the potential pharmacological interest of bryozoan natural products by investigating the antimicrobial activity of 16 ether (EE) and 16 butanol extracts (BE) from Antarctic bryozoans against a diverse array of sympatric bacterial populations and bacterial strain collections. Antibacterial testing 6 Antarctic bacteria: Psychrobacter luti and Shewanella livingstonensis (F. Pharmacy, UB) 4 new isolated strains from stone (BAC03 and BAC02.1) sediment (BAC02.2) or sponge (Haliclona sp; BAC84) 2 pathogenic bacteria: Escherichia coli and Bacillus cereus •Paper discs + 20 µL of solution -> on the surface of inoculated plates (agar diffusion method