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Microorganisms from special ecological niches, such as the marine invertebrate symbionts, are a source of several natural products. A classic model of symbiosis occurs between the bivalve mollusks of wood borings of the family Teredinidae and an abundant population of γ-proteobacteria that inhabit the gills of the animal. These bacteria help in the nutrition and chemical defense of the host, through the production of enzymes such as glycosyl hydrolases and toxic compounds such as tartrolons. However, the metabolic potential of these endosymbionts is still far from fully explored. This study is divided into two chapters. In the first one, we aimed prospect bioactive substances produced by teredinidae’s symbionts through the integration of massive shotgun type sequencing and microbial culture dependent techniques. In the second, the objective was to evaluate the cytotoxic potential of the tartrolon D compound produced by the endosymbionts. First of all, 19 teredinids were collected and identified as belonging to the species Neoteredo reynei, Lyrodus massa and Bankia sp.. The metagenomic DNA of the gills, digestive glands and intestine of 3 N. reynei specimens was sequenced and taxonomic and functional signatures were analyzed. It was verified that the gills samples are enriched (abundance> 80%) for hits of the Bacteria domain, but this microbioma is little diverse, being constituted mostly by γ-proteobacteria. The intestinal and digestive gland samples, on the other hand, have a discrete microbial population, but cover a greater diversity of associated classes. In addition to being enriched of hits for α-proteobacteria and negativicutes in relation to the gills. The profile of the functional signatures is similar between microbiomes, but the gills have some enrichment of functions that help in their interaction with the host, such as the function of nitrogen metabolism and synthesis, and the function of iron capture and metabolism. From the cross-assembly and batching, two genomes were recovered from the gill metagenomes. The tissues were processed, homogenized and plated in SBM-S and SMB-C medium in serial dilutions. Cultures were grown in SBM-C or SBM-S broth and cryopreserved. When cultivating the homogenates of the gills, intestines and digestive glands, 247 strains were isolated. Ethyl acetate solvent was used for the production of organic extracts of 46 bacteria, however 14 crude extracts were considered active (inhibition of growth> 75%) in HCT 116 human colorectal cancer cells at 50 μg / mL concentration after 72 h of incubation. The mean inhibitory concentrations (IC50) were estimated for the active extracts and ranged from 0.6 to 26 μg / mL. In parallel, the taxonomic identification of 46 isolates showed that the cultivable microorganisms of the species of Neoteredo reynei and Lyrodus mass are composed mainly by bacteria of the proteobacteria, actinobacteria and firmicutes phyla. The antiproliferative effect of tartrolon D was investigated by the SRB assay in 4 normal (L929 and HEK293A) tumor lines (HCT 116, B16-F10, PC-3M and MCF-7). The compound was able to produce a cytostatic and cytotoxic effect in all strains evaluated, with emphasis on HCT 116 and B16F-10 strains, which were more sensitive to treatment with IC 50 equivalent to 0.04 μM and 0.3 μM, respectively. Through differential staining, some morphological changes were observed in HCT 116 cells when incubated with the compound for 24 hours. These changes include mitotic figures, membrane instability, DNA fragmentation, and the reduction of cell volume accompanied by chromatin condensation. In addition, the analysis of the cell morphology by flow cytometry showed an increase in the populations of cells with high granularity and with reduced size after 48h of incubation with 24.3 μM of tartrolon D. The decrease in cell numbers and the increase in percentages of non-viable cells were also detected for the highest concentration tested. The cell cycle profile of HCT 116 cells incubated with 24.3 μM of the compound for 24 and 48 hours demonstrated accumulation of DNA in G2 / M, and increased DNA fragmentation. Previously, no previous study of mechanism of action had been performed with tartrolon D. Microrganismos de nichos ecológicos especiais, tais como os simbiontes de invertebrados marinhos, são uma fonte de diversos produtos naturais. Um modelo clássico de simbiose ocorre entre os moluscos bivalves perfurantes de madeira da família Teredinidae e uma abundante população de γ-proteobactérias que habitam as brânquias do animal. Essas bactérias auxiliam na nutrição e na defesa química do hospedeiro, através da produção de enzimas, como glicosil-hidrolases, e de compostos tóxicos, como os tartrolons. Contudo, o potencial metabólico desses endossimbiontes ainda está longe de ser totalmente explorado. O presente trabalho encontra-se divido em dois capítulos. No primeiro, objetivou-se prospectar substâncias bioativas produzidas por bactérias associadas aos moluscos da família Teredinidae através da integração de sequenciamento massivo tipo shotgun e de técnicas dependente de cultivo microbiano. No segundo, objetivou-se avaliar o potencial citotóxico do composto tartrolon D produzido pelos endossimbiontes. No total, 19 teredinídeos foram coletados e identificados como pertencentes às espécies Neoteredo reynei, Lyrodus massa e Bankia sp.. O DNA metagenômico das brânquias, das glândulas digestivas e do intestino de 3 espécimes de N. reynei foi sequenciado e as assinaturas taxonômicas e funcionais foram analisadas. Constatou-se que as amostras de brânquias são enriquecidas (abundância > 80%) para hits do domínio Bacteria, porém esse microbioma é pouco diverso, sendo constituído em sua maioria por γ-proteobacterias. As amostras de intestinos e glândulas digestivas, por outro lado, possuem população microbiana discreta, mas abrangem maior diversidade de classes associadas. Além de serem enriquecidas de hits para α-proteobacterias e negativicutes em relação às brânquias. O perfil das assinaturas funcionais é similar entre os microbiomas, porém as brânquias possuem enriquecimento de algumas funções que auxiliam em sua interação com o hospedeiro, como a função de metabolismo e síntese de nitrogênio, e a função de captura e metabolismo de ferro. A partir de montagem cruzada foram recuperados dois genomas a partir dos metagenomas das brânquias Os tecidos foram processados, homogeneizados e plaqueados em meio SBM-S e SMB-C em diluições seriadas. As culturas foram crescidos em caldo SBM-C ou SBM-S e criopreservadas. Ao cultivar os homogeneizados das brânquias, do intestino e das glândulas digestivas foram isoladas 247 cepas. O solvente acetato de etila foi utilizado para a produção de extratos orgânicos de 46 bactérias, entretanto 14 extratos brutos foram considerados ativos (inibição do crescimento > 75%) em células de câncer colorretal humano HCT 116 na concentração de 50 μg/mL após 72h de incubação. As concentrações inibitórias médias (CI50) fora estimadas para os extratos ativos e variaram entre 0,6 a 26 μg/mL. Em paralelo, a identificação taxonômica de 46 isolados demonstrou que os microrganismos cultiváveis das espécies de Neoteredo reynei e Lyrodus massa são compostos em sua maioria por bactérias dos filos proteobacterias, actinobacterias e firmicutes. O efeito antiproliferativo do tartrolon D foi então investigado pelo ensaio do SRB em 4 linhagens tumorais (HCT 116, B16-F10, PC-3M e MCF-7) e normais (L929 e HEK293A). O composto foi capaz de produzir um efeito citostático e citotóxico em todas as linhagens avaliadas, com destaque as linhagens HCT 116 e B16F-10, as quais foram mais sensíveis ao tratamento, com CI50 equivalentes a 0,04 μM e 0,3 μM, respectivamente. Através de coloração diferencial, algumas alterações morfológicas foram observadas nas células HCT 116 quando incubadas com o composto por 24 horas. Essas alterações incluem o aparecimento de figuras mitóticas, a instabilidade da membrana, a fragmentação de DNA, e principalmente a redução do volume celular acompanhada da condensação de cromatina. Adicionalmente, a análise da morfologia celular por citometria de fluxo, demonstrou um aumento das populações de células com alta granulosidade e com tamanho reduzido após 48h de incubação, na concentração de 24,3 μM. Detectou-se também a diminuição da quantidade de células e o aumento nas porcentagens de células não viáveis para a maior concentração testada. O perfil do ciclo celular das células da linhagem HCT 116 incubadas com o 24,3 μM do composto por 24 e 48 horas demonstrou o acúmulo do DNA em G2/M, e o aumento na fragmentação de DNA. Anteriormente, nenhum estudo prévio de mecanismo de ação havia sido realizado com o tartrolon D. Portanto, este trabalho se configura como o primeiro relato das alterações provocadas por esse composto em células tumorais.

Extreme environments are defined as those habitats in which human life is not possible. Thus, from a human point of view, those forms of life thriving in those conditions will be called as "extremophiles". Environments that harbor this kind of life are widespread around the globe, including hot springs, hydrothermal vents, deep ocean, deserts, high-altitude environments, brines and soda lakes, nuclear reactors, ice sheets, and toxic wastes (Stetter 1999; Miroshnichenko and Bonch-Osmolovskaya 2006; Raymond et al. 2008; Dib et al. 2009; Albarracín et al. 2011, 2012; Albarracín and Farías 2012). Including representatives of all three domains of life, that is, Bacteria, Archaea, and Eukaryote, extremophiles are denoted by a descriptive term, usually a word with Greek or Latin roots followed by the combining form phile Greek term for "loving." Their names are given depending on the physicochemical factor they withstand, such as thermophiles, psychrophiles (organisms growingbest at high or low temperatures), acidophiles, alkaliphiles (organisms optimally adapted to acidic or basic pH values), barophiles (organisms that grow best under pressure), xerophiles (resistant to desiccation), or halophiles (organisms that require high salt concentrations for growth). In addition, a much larger diversity of organisms can tolerate extreme conditions and grow, but not necessarily optimally in extreme habitats; these organisms are defined as extremotrophs or extreme tolerant(Stojanović et al. 2008; Madigan et al. 2014).The discovery of extremophiles has drastically changed our understanding toward the diversity of life itself and the conditions under which it can be sustained. Thus, extremophiles are of interest for both basic and applied science. Indeed, these "superbugs" hold many interesting biological secrets, such as the biochemical limits on the stability of macromolecules and the genetic instructions for constructingstable macromolecules to one or another extreme. They are very important in the study of origins of life; many extremophiles, in particular the hyperthermophiles, lie close to the "universal ancestor" of all existent life on Earth. This exciting realization has fueled much research on these organisms to understand the nature of primitive life forms, how the first cells "made a living" in Earth's early days, and how early organisms set the stage for the evolution of modern life forms (Madigan 2000). Also, astrobiologists are particularly interested in studying extremophiles, as many organisms of this type are capable of surviving in environments similar to those from other planets; Mars may have regions in its deep subsurface that could harbor extremophiles. Likewise, the subsurface water ocean of Jupiter's moon Europa may harbor a similar "extreme" life (Westall et al. 2002; Edwards et al. 2005).Extremophiles are also the focus of biotechnological processes. Due to their amazing array of enzymes and other chemical compounds, they have provided products to be used under extreme conditions in applications as diverse as laundry detergent additives and the genetic identification of criminals (Ito et al. 1998).The aim of this work is to offer a short, but comprehensive report on the biology and biodiversity of extremophilic microbes thriving in particular environments around the globe together with a description on their importance for basic research and common biotechnological applications. Fil: Rasuk, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Ferrer, Gabriela Mónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Farias, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Albarracín, Virginia Helena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina