Freshwater fungi are key decomposers of organic material and play important roles in nutrient cycling, bio-remediation and ecosystem functioning. Although aquatic fungal communities respond to pollution, few studies have quantitatively assessed the effect of freshwater contamination on fungal diversity and composition; and knowledge is scarcer for tropical systems. Here we help fill this knowledge gap by studying a heavily-contaminated South American river spanning a biodiversity hotspot. We collected 30 water samples scattered across a quality gradient over two seasons and analyzed them using Terminal Restriction Fragment Length Polymorphisms (T-RFLP) coupled with 454 Pyrosequencing. Using T-RFLP we identified 451 and 442 Operational Taxonomy Units (OTUs) in the dry and rainy seasons respectively, whereas Pyrosequencing revealed 48,553 OTUs from which 11% were shared between seasons. Although 68% of all identified OTUs and 51% of all identified phyla remained unidentified, dominant fungal phyla included the Ascomycota, Basidiomycota, Chytridiomycota, Glomeromycota, Zygomycota and Neocallimastigomycota, while Calcarisporiella, Didymosphaeria, Mycosphaerella (Ascomycota) and Rhodotorula (Basidiomycota) were the most abundant genera. Fungal diversity was affected by pH and dissolved iron, while community composition was influenced by dissolved oxygen, pH, nitrate, biological oxygen demand, total aluminum, total organic carbon, total iron and seasonality. The presence of potentially pathogenic species was associated with high pH. Furthermore, geographic distance was positively associated with community dissimilarity, suggesting that local conditions allowed divergence among fungal communities. Overall, our findings raise potential concerns for human health and the functioning of tropical river ecosystems and they call for improved water sanitation systems.

Carnivorous plant species, such as Utricularia spp., capture and digest prey. This digestion can occur through the secretion of plant digestive enzymes and/or by bacterial digestive enzymes. To comprehend the physiological mechanisms of carnivorous plants, it is essential to understand the microbial diversity related to these plants. Therefore, in the present study, we isolated and classified bacteria from different organs of Utricularia breviscapa (stolons and utricles) and from different geographic locations (São Paulo and Mato Grosso). We were able to build the first bacterium collection for U. breviscapa and study the diversity of cultivable bacteria. The results show that U. breviscapa bacterial diversity varied according to the geographic isolation site (São Paulo and Mato Grosso) but not the analyzed organs (utricle and stolon). We reported that six genera were common to both sample sites (São Paulo and Mato Grosso). These genera have previously been reported to be beneficial to plants, as well as related to the bioremediation process, showing that these isolates present great biotechnological and agricultural potential. This is the first report of an Acidobacteria isolated from U. breviscapa. The role of these bacteria inside the plant must be further investigated in order to understand their population dynamics within the host.

The genus Micromonospora comprises actinomycetes with high biotechnological potential, due to their ability to produce secondary metabolites and enzymes. In this study, we report the draft genome sequence of Micromonospora sp. NBS 11-29, which showed antibacterial, cellulolytic, and xylanolytic activities under in vitro conditions.

Aos meus pais Rosa Maria e Laércio Rezende, por contribuírem para minha formação biológica, como cidadão e profissional. À minha irmã Kely Lima e meus sobrinhos amados; Mateus, Gabriel e Carol, por me motivarem a seguir em frente. Ao meu orientador Prof. Dr. Welington Luiz de Araújo, pelas oportunidades a mim oferecidas, pelas longas caronas com boas conversas e pelos conselhos. Às amigas Eliane Gonçalves e Lina Rada, por toda paciência, pelos ombros encharcados, pelas conversas de apoio e também pelas hospedagens. Às amigas Emy Mano, Priscila Romano e Ana Marie pelas longas conversas e por todo carinho a mim oferecido. À Mabel Ortiz, Raíssa Mesquita e Aline Neves, pelo companheirismo, pelos vários conselhos e por toda força incentivadora. À Lilandra Rios e Ricardo O lchanheski pela amizade e auxílio durante os experimentos. À Luciana Francisco, por me ensinar os primórdios da Microbiologia Clássica. Ao colega Almir Ferreira, por me ensinar os primeiros passos em Biologia Molecular, por toda ajuda computacional e paciência, além de inspiração e incentivo desde a IC. À Vanessa Feitosa pela amizade, pelas conversas sempre boas e incentivo constante.