Background The Rhizobiales (Proteobacteria) order is an abundant and diverse group of microorganisms, being extensively studied for its lifestyle based on the association with plants, animals, and humans. New studies have demonstrated that the last common ancestor (LCA) of Rhizobiales had a free-living lifestyle, but the phylogenetic and metabolism characterization of basal lineages remains unclear. Here, we used a high-resolution phylogenomic approach to test the monophyly of the Aestuariivirgaceae family, a new taxonomic group of Rhizobiales. Furthermore, a deep metabolic investigation provided an overview of the main functional traits that can be associated with its lifestyle. We hypothesized that the presence of pathways (e.g., Glycolysis/Gluconeogenesis) and the absence of pathogenic genes would be associated with a free-living lifestyle in Aestuariivirgaceae. Results Using high-resolution phylogenomics approaches, our results revealed a clear separation of Aestuariivirgaceae into a distinct clade of other Rhizobiales family, suggesting a basal split early group and corroborate the monophyly of this group. A deep functional annotation indicated a metabolic versatility, which includes putative genes related to sugar degradation and aerobic respiration. Furthermore, many of these traits could reflect a basal metabolism and adaptations of Rhizobiales, as such the presence of Glycolysis/Gluconeogenesis pathway and the absence of pathogenicity genes, suggesting a free-living lifestyle in the Aestuariivirgaceae members. Conclusions Aestuariivirgaceae (Rhizobiales) family is a monophyletic taxon of the Rhizobiales with a free-living lifestyle and a versatile metabolism that allows these microorganisms to survive in the most diverse microbiomes, demonstrating their adaptability to living in systems with different conditions, such as extremely cold environments to tropical rivers.

Aim:The main goal of the study was to determine the effect of the Morato Fall in the richness and composition of the aquatic animal community; Methods: We compared faunal richness and similarity in four substrate samples from two pools separated by a waterfall in the Morato River, southern Brazil; Results: The richness was not significantly different, although the upstream pool had 72 taxa and the downstream one just 65. On the other hand, composition was poorly similar, just a 36.5% similarity between the two sites; Conclusions: That indicates a strong influence of the waterfall, mainly on organisms which spent its entire life cycle on the water, such as fish and small crustaceans. That allow aquatic insects, a group with airborne adult phase and, therefore, able to disperse up to the upstream pool, to evolve with less predatory pressure, becoming the top group in the food web of this environment.Resumo: Objetivo: O objetivo principal foi determinar o efeito do Salto Morato na riqueza e na composição da comunidade aquática; Métodos: Nós comparamos a riqueza e a similaridade da fauna em amostras de quatro substratos de dois poços separados por uma cachoeira no Rio Morato, no sul do Brasil; Resultados: A riqueza não foi significativamente diferente, embora o poço acima do salto tenha apresentado 72 taxa e o poço abaixo do salto apenas 65. Por outro lado, a fauna apresentou-se pouco similar, com apenas 36,5% de similaridade entre os poços; Conclusões: Isso indicou uma forte influencia da presença da cachoeira, principalmente nos organismos que tem todo o ciclo de vida na água, como os peixes e pequenos crustáceos. Isso permite que os insetos aquáticos, que tem fase adulta alada e, portanto, a capacidade de se dispersar até o poço acima do salto, se desenvolvam sem a pressão de seus principais predadores e tornem-se, naquele ambiente, os organismos de topo da teia trófica.

Human activities can cause degradation of ecosystems and interfere with the availability of the environmental services they provide to society itself. Preventing degradation from happening is the best strategy to ensure the availability of these services, and for this to happen, human activities have to be constantly monitored. One of the most used monitoring strategies is the measurement of indicators that represent the homeostasis of the environment and have the sensitivity to identify the initial signs of degradation. In this study we characterize the microbial communities of continental aquatic environments in the Amazon, Atlantic Rainforest, Cerrado and Caatinga and use this data to select indicators of oil exploration activity impacts (oil fields operating for at least 25 years with no history of spills). We evaluated the taxonomic and functional diversity through 16S gene sequencing and GeoChip 5.0M functional gene microarray. Results from water, sediment, biofilm and stream banks soil samples influenced by oil fields were compared to minimally impacted reference areas. In addition to the microbial communities, we analyse physical-chemical parameters of water, inorganic parameters in water, soil and sediment and organic parameters (n-alkanes and polycyclic aromatic hydrocarbons) in water and sediment. All sampling stations showed microbial communities with high species richness and more than 80% functional genes detected with GeoChip. The microbial communities presented low taxonomic similarity, sharing less than 30% of the species with each other. On the other hand, they showed high functional similarity, sharing more than 70% of the genes. The main impact of the oil exploration activity was land use, as evidenced by the increase in the concentration of metallic ions, the electrical conductivity, the number of genes related to the metal homeostasis, the abundance of metal related oxidative stress response genes and the number of soil microbial species in the water of the streams influenced by the exploration activity. No evidence of hydrocarbon contamination was found at the sample stations evaluated. Several microbial species and functional genes were identified as promising indicators of oil exploration activity in streams but it was not possible to link these indicators to specific taxonomic groups nor to preferential metabolic activities. This points to a paradigm shift in the use of indicators for environmental monitoring, indicating that instead of indicator species or indicator functional groups, it will be more promising to develop a concept related to indicator genetic sequences.