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The deep-sea environments of the South Atlantic Ocean are less studied in comparison to the North Atlantic and Pacific Oceans. With the aim of identifying the deep-sea bacteria in this less known ocean, 70 strains were isolated from eight sediment samples (depth range between 1905 to 5560 m) collected in the eastern part of the South Atlantic, from the equatorial region to the Cape Abyssal Plain, using three different culture media. The strains were classified into three phylogenetic groups, Gammaproteobacteria, Firmicutes and Actinobacteria, by the analysis of 16s rRNA gene sequences. Gammaproteobacteria and Firmicutes were the most frequently identified groups, with Halomonas the most frequent genus among the strains. Microorganisms belonging to Firmicutes were the only ones observed in all samples. Sixteen of the 41 identified operational taxonomic units probably represent new species. The presence of potentially new species reinforces the need for new studies in the deep-sea environments of the South Atlantic.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-127) contains supplementary material, which is available to authorized users.

Acanthamoeba is a “Trojan horse” of the microbial world. The aim of this study was to identify the presence of Pseudomonas as an amoeba-resistant microorganism in 12 isolates of Acanthamoeba. All isolates showed the genus Pseudomonas spp. as amoeba-resistant microorganisms. Thus, one can see that the Acanthamoeba isolates studied are hosts of Pseudomonas.

The main sulfate-reducing (SRB) and sulfur-oxidizing bacteria (SOB) in six wastewater treatment plants (WWTPs) located at southern Brazil were described based on high-throughput sequencing of the 16S rDNA. Specific taxa of SRB and SOB were correlated with some abiotic factors, such as the source of the wastewater, oxygen content, sample type, and physical chemical attributes of these WWTPs. When the 22 families of SRB and SOB were clustered together, the samples presented a striking distribution, demonstrating grouping patterns according to the sample type. For SOB, the most abundant families were Spirochaetaceae, Chromatiaceae, Helicobacteriaceae, Rhodospirillaceae, and Neisseriaceae, whereas, for SRB, were Syntrophaceae, Desulfobacteraceae, Nitrospiraceae, and Desulfovibriaceae. The structure and composition of the major families related to the sulfur cycle were also influenced by six chemical attributes (sulfur, potassium, zinc, manganese, phosphorus, and nitrogen). Sulfur was the chemical attribute that most influenced the variation of bacterial communities in the WWTPs (λ = 0.14, p = 0.008). The OTUs affiliated to Syntrophus showed the highest response to the increase of total sulfur. All these findings can contribute to improve the understanding in relation to the sulfur-oxidizing and sulfate-reducing communities in WWTPs aiming to reduce HS emissions.

Aims:  Paenibacillus isolates were selected to test antimicrobial activity against bacteria, filamentous fungi and yeasts isolates, with the purpose of finding new bacterium species for microbiological control. Methods and Results:  Fifty‐five strains belonging to 15 species of Paenibacillus were inoculated on trypticase soya agar, potato dextrose agar and sabouraud agar plates in order to evaluate their antimicrobial activity against 16 indicator bacteria, 14 filamentous fungi and six yeasts isolates, both reference and field strains. After these screening, culture supernatant of 17 isolates was prepared. Twenty‐five Paenibacillus isolates presented antimicrobial activity, where seven species (Paenibacillus chibensis; P. koreensis; P. illinoiensis; P. validu; P. pabuli; P. brasilensis and P. peoriae) stood out inhibiting at least 13 of the 16 indicator bacteria. Only 14 of the 55 isolates exhibited antifungal activity. P. peoriae inhibited 13 among the 14 filamentous fungi and all yeasts indicator strains. Fourteen isolates produced culture supernatant with antimicrobial activity. Conclusions:  Among the 55 isolates analysed, 25 exhibited a broad inhibition spectrum against bacteria and pathogenic fungi. P. validus, P. chibensis, P. koreensis and P. peoriae isolates proved to be the subject matter for studies on the production of antimicrobial agents. Significance and Impact of the Study:  The present study revealed other two species with antimicrobial activity: P. validus and P. chibensis, and it contributed to enhance Paenibacillus biocontrolling potential, proving that it exhibit a broad action spectrum.