As Streptomyces have shown an outstanding capacity for drug production, different campaigns in geographically distant locations currently aim to isolate new antibiotic producers. However, many of these newly isolated Streptomyces strains are classified as identical to already described species. Nevertheless, as discrepancies in terms of secondary metabolites and morphology are possible, we compared two Streptomyces strains with identical 16S rRNA gene sequences but geographically distant origins. Chosen were an Easter Island Streptomyces isolate (Streptomyces sp. SN25_8.1) and the next related type strain, which is Streptomyces griseus subsp. griseus DSM 40236T isolated from Russian garden soil. Compared traits included phylogenetic relatedness based on 16S rRNA gene sequences, macro and microscopic morphology, antibiotic activity and secondary metabolite profiles. Both Streptomyces strains shared several common features, such as morphology and core secondary metabolite production. They revealed differences in pigmentation and in the production of accessory secondary metabolites which appear to be strain-specific. In conclusion, despite identical 16S rRNA classification Streptomyces strains can present different secondary metabolite profiles and may well be valuable for consideration in processes for drug discovery.

The presence of two known anthraquinones, Lupinacidin A and Galvaquinone B, which have antitumor activity, has been identified in the sea anemone (Gyractis sesere) from Easter Island. So far, these anthraquinones have been characterized from terrestrial and marine Actinobacteria only. In order to identify the anthraquinones producer, we isolated Actinobacteria associated with the sea anemone and obtained representatives of seven actinobacterial genera. Studies of cultures of these bacteria by HPLC, NMR, and HRLCMS analyses showed that the producer of Lupinacidin A and Galvaquinone B indeed was one of the isolated Actinobacteria. The producer strain, SN26_14.1, was identified as a representative of the genus Verrucosispora. Genome analysis supported the biosynthetic potential to the production of these compounds by this strain. This study adds Verrucosispora as a new genus to the anthraquinone producers, in addition to well-known species of Streptomyces and Micromonospora. By a cultivation-based approach, the responsibility of symbionts of a marine invertebrate for the production of complex natural products found within the animal’s extracts could be demonstrated. This finding re-opens the debate about the producers of secondary metabolites in sea animals. Finally, it provides valuable information about the chemistry of bacteria harbored in the geographically-isolated and almost unstudied, Easter Island.

4Agri-Food Laboratories-Concepción, SGS Chile Ltda. Américo Vespucio 820, Parque Industrial Las Arucas, Talcahuano, ChileResumen.-En la última década se ha incrementado el interés por la búsqueda de moléculas con potencial biomédico y amigable para el ambiente. Desde esta perspectiva, la búsqueda de principios bioactivos de origen marino ha permitido valorar la diversidad biológica presente en los ecosistemas acuáticos. En el Phylum Equinodermata, se destaca la familia Holothuridae, por su capacidad de sintetizar moléculas como saponinas y otros metabolitos secundarios de alto interés farmacológico debido a su capacidad hemolítica, antitumoral, anti-inflamatoria, antimicrobiana, citostática y antineoplásica. El interés del presente trabajo se centró en la caracterización de un extracto purificado obtenido desde Athyonidium chilensis (Holothuria) mediante técnicas cromatográficas y de espectrometría de masas, con la posterior evaluación de su potencial bioactivo sobre modelos in vitro. Como resultado de estos análisis, se identificaron 2 saponinas. La primera con un peso molecular de 1522 Da y altamente conjugada con monosacáridos. La segunda con un peso molecular de 764 Da fue identificada como holoturinósido D. Respecto a los resultados de la actividad biológica del extracto purificado, éste mostró actividad antibacteriana, antifúngica y citotóxica frente a una línea celular de neuroblastoma. Los resultados de este estudio se convierten en la primera caracterización de moléculas con actividad biológica desde Athyonidium chilensis. Palabras clave: Holothuria, holoturinósido D, saponinaAbstract.-In the last decade, the interest for searching molecules with biomedical potential as well as innocuous for the environment has been increased. Under this perspective, the search for bioactive principles of marine origin has allowed to value the biological diversity present in aquatic systems. In phylum Echinodermata, the family Holothuridae is distinguished by its capacity of synthesizing molecules such as saponins and other secondary metabolites of high pharmacological interest because of their interesting haemolytic, antitumor, anti-inflammatory, antimicrobial, cytostatic and antineoplastic capacity. The aim of the present study was focused on the characterization of a purified extract obtained from Athyonidium chilensis (Holothuria) by chromatographic and mass spectrometric techniques and the later assessment of its bioactive potential on in vitro models. As a result of these analyses 2 saponins were identified. The first with a molecular weight of 1522 Da and highly conjugated with monosaccharides. The second with a molecular weight of 764 Da was identified as holothurinoside D. The biological activity of the purified extract showed antibacterial, antifungal and cytotoxic activity on a neuroblastoma cell line. Outcomes of this study correspond to the first characterization of molecules with biological activity from Athyonidium chilensis.