Cuba is one of the richest places in malacological fauna in the world, especially in land snails, hosting a high degree of endemism. A study on the distribution of freshwater molluscs that occur within the limits of protected areas was carried out. The objective was to determine the status of the endemic species and the potential threats of introduced snails. It was found that the inclusion of freshwater molluscs is not a criterion for proposing protected areas no matter how ecologically important they actually can be. A total of 42 species of freshwater molluscs occur in Cuba, but only 24 exist in the National System of Protected Areas. More critical is the fact that of the 10 Cuban endemics, three are not protected and the distribution data on all of them are not abundant. Introduced species such as Tarebia granifera and Melanoides tuberculata are spread throughout the country and might be a threat for endemics and other native snails. Data on the distribution of endemic molluscs is presented and the role of some introduced/invasive species is discussed. Keywords: Molluscs, Freshwater, Ecology, Conservation, Cuba Resumen Cuba es uno de los sitios de mayor riqueza de moluscos en el mundo, especialmente de moluscos terrestres en donde muestra un alto porciento de endemismo. Se realizó un estudio sobre la distribución de moluscos fluviales que existen dentro de los límites de las áreas protegidas con el objetivo de determinar el estado de las especies endémicas y las amenazas potenciales de algunas especies introducidas. Se encontró que la presencia de moluscos fluviales no es utilizada como criterio a la hora de proponer áreas protegidas independientemente de la importancia ecológica que presentan. Un total de 42 especies de moluscos fluviales existen en Cuba, pero solo 24 aparecen en el Sistema Nacional de Áreas Protegidas. Más crítico es el hecho de que de las diez especies endémicas (23.8%), tres no se encuentran protegidas y los datos sobre su distribución no son abundantes. Especies introducidas como Tarebia granifera y Melanoides tuberculata se han dispersado por todo el país y pueden ser una amenaza para especies endémicas y otras especies nativas. Se presentan datos sobre la distribución de moluscos endémicos y se discute sobre el papel de algunas especies introducidas / invasivas sobre los moluscos endémicos.

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Mollusks have been widely investigated for antimicrobial peptides because their humoral defense against pathogens is mainly based on these small biomolecules. In this report, we describe the identification of three novel antimicrobial peptides from the marine mollusk Nerita versicolor. A pool of N. versicolor peptides was analyzed with nanoLC-ESI-MS-MS technology, and three potential antimicrobial peptides (Nv-p1, Nv-p2 and Nv-p3) were identified with bioinformatical predictions and selected for chemical synthesis and evaluation of their biological activity. Database searches showed that two of them show partial identity to histone H4 peptide fragments from other invertebrate species. Structural predictions revealed that they all adopt a random coil structure even when placed near a lipid bilayer patch. Nv-p1, Nv-p2 and Nv-p3 exhibited activity against Pseudomonas aeruginosa. The most active peptide was Nv-p3 with an inhibitory activity starting at 1.5 µg/mL in the radial diffusion assays. The peptides were ineffective against Klebsiella pneumoniae, Listeria monocytogenes and Mycobacterium tuberculosis. On the other hand, these peptides demonstrated effective antibiofilm action against Candida albicans, Candida parapsilosis and Candida auris but not against the planktonic cells. None of the peptides had significant toxicity on primary human macrophages and fetal lung fibroblasts at effective antimicrobial concentrations. Our results indicate that N. versicolor-derived peptides represent new AMP sequences and have the potential to be optimized and developed into antibiotic alternatives against bacterial and fungal infections.