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Human activities on the Earth's surface change the landscape of natural ecosystems. Mining practices are one of the most severe human activities, drastically altering the chemical, physical and biological properties of the soil environment. Bacterial communities in soil play an important role in the maintenance of ecological relationships. This work shows bacterial diversity, metabolic repertoire and physiological behavior in five ecosystems samples with different levels of impact. These ecosystems belong to a historical area in Iron Quadrangle, Minas Gerais, Brazil, which suffered mining activities until its total depletion without recovery since today. The results revealed Proteobacteria as the most predominant phylum followed by Acidobacteria, Verrucomicrobia, Planctomycetes, and Bacteroidetes. Soils that have not undergone anthropological actions exhibit an increase ability to degrade carbon sources. The richest soil with the high diversity was found in ecosystems that have suffered anthropogenic action. Our study shows profile of diversity inferring metabolic profile, which may elucidate the mechanisms underlying changes in community structure in situ mining sites in Brazil. Our data comes from contributing to know the bacterial diversity, relationship between these bacteria and can explore strategies for natural bioremediation in mining areas or adjacent areas under regeneration process in iron mining areas.

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Although the use of vinasse as a waste helps replenish soil nutrients and improves the quality of the sugarcane crop, it is known that vinasse residues alter the diversity of bacteria naturally present in the soil. The actual impacts of vinasse application on the selection of bacterial taxa are not understood because no studies have addressed this phenomenon directly. Analysis of 16S rRNA gene clone sequences from four soil types showed that the soil planted with sugarcane and fertilized with vinasse has a high diversity of bacteria compared to other biomes, where Acidobacteria were the second most abundant phylum. Although the composition and structure of bacterial communities differ significantly in the four environments (Libshuff's test), forest soils and soil planted with sugarcane without vinasse fertilizer were similar to each other because they share at least 28 OTUs related to Rhizobiales, which are important agents involved in nitrogen fixation. OTUs belonging to Actinomycetales were detected more often in the soil that had vinasse applied, indicating that these groups are more favored by this type of land management.

The draft sequence of the genome of Bradyrhizobium elkanii 587 is presented. This was obtained using Illumina Next-Gen DNA sequencing combined with Sanger sequencing. Genes for the pathways involved in biological nitrogen fixation (the nif gene cluster), nod genes including nodABC, and genes for the type III protein secretion system (T3SS) are present. Bradyrhizobium elkanii 587 is a nitrogen-fixing bacterium that nodulates soybean and is used in commercial inoculants in Brazil (7).The draft genome sequence of B. elkanii 587 was obtained using a combination of Illumina and Sanger reads. A total of 6,020,858 endpaired reads were de novo assembled using Velvet (11) with an average read depth of 28-fold; 42,785 Sanger reads were added to the assembly, resulting in 260 scaffolds (N 50 , 54,941 bp). Scaffold ordering was carried out using Bradyrhizobium japonicum USDA110 as a reference. B. elkanii 587 contains one circular chromosome of 8.8 Mbp with a GϩC content of 62.9%, and no plasmid was detected. Annotation of 9,250 potential open reading frames (ORFs) and 71 tRNA genes was performed using the RAST program (1). Genes of interest were curated and analyzed manually. A single rRNA operon was found, as in B. japonicum USDA110 (4).Genes for the same metabolic pathways found in B. japonicum were found in the genome of B. elkanii 587. Genes encoding the Entner-Doudoroff and Embden-Meyerhof-Parnas pathways for carbohydrate degradation are present.The nif genes nifDKENX-(orf1 to orf7)- fixBCX are present in one cluster. The genes related to nodulation are organized in two regions. The first contains 19 genes, nodUIJ, nopM, nodZ, fixR, nifA, nopM, fixAKLNOGHI, noeE, and nodQP, and includes the nif transcriptional activator (the nifA gene). The second cluster contains five genes, nodD1 and nodABCS. The genes nodT, nopB, nodU, nolY, nolL, and nolV were identified outside the clusters.