A total of 1037 individuals living in five different sociogeographic regions of Brazil were studied in relation to 12 short tandem repeat polymorphisms. The objective was to assess the degree of European, African, and Amerindian contributions to their gene pools. Although most of the genetic variability was found within regions, significant differences were also observed between regions. The estimated relative proportions of the above-indicated continental contributions showed intermediate values between those obtained with uniparental (mtDNA, Y-chromosome) data, and a higher percentage of European heritage as compared to previous autosome results. A north-south trend of increasing European contribution was also found, in agreement with the history of the Brazilian population.
The aim of this study was to screen Streptomycetes isolates with antimicrobial and antiviral activity, in a search for new metabolites. The isolates were obtained from a composting process, and identified based on morphological characteristics and molecular biological methods. The antimicrobial activity was determined using the double-layer agar method against 53 test organisms (bacteria, yeasts, and filamentous fungi). All isolates were grown in submerged culture, in mineral salts-starch-casein (SC) broth and ISP2 media, and the filtrate cultures were used in the assays for antibacterial and antiviral activity. Bovine Herpes virus (BoHV-I) was used for the antiviral activity. The morphological and molecular characteristics confirmed that all 25 isolates belonged to the genus Streptomyces. In the assay for antimicrobial activity, 80% of the Streptomyces isolates were able to inhibit at least one of the test organisms. Of these, 80% were active against bacteria and 45% against fungi. Eight of the isolates showed a broad spectrum of inhibitory activity; of these, the isolate Streptomyces spp. 1S was able to inhibit 46 of the test organisms, and, most importantly, the 16 Gramnegative strains were inhibited. Of the 25 isolates, 44.4% of the isolates were able to grow and produce bioactive metabolites when grown in submerged culture. Four extracts showed a cytopathic effect in 10 CCID 50 MDBK cell, even though no viricidal effect was observed. The results obtained with these isolates indicated good biotechnological potential of these Streptomyces strains.
The composting process is a viable alternative for the recycling of household organic waste and sewage sludge generated during wastewater treatment. However, this technique can select microorganisms resistant to antimicrobials and heavy metals as a result of excess chemicals present in compost windrow. This study evaluates the antimicrobial multiresistant and tolerance to heavy metals in bacteria isolated from the composting process with sewage sludge. Fourteen antimicrobials were used in 344 strains for the resistance profile and four heavy metals (chromium, copper, zinc, and lead) for the minimum biocide concentration assay. The strains used were from the sewage sludge sample (beginning of the process) and the compost sample (end of the process). Strains with higher antimicrobial and heavy metal profile were identified by 16S rRNA gene sequencing. The results showed a multiresistant profile in 48 % of the strains, with the highest percentage of strains resistant to nitrofurantoin (65 %) and β-lactams (58 %). The strains isolated from the sewage sludge and the end of the composting process were more tolerant to copper, with a lethal dose of approximately 900 mg L(-1) for about 50 % of the strains. The genera that showed the highest multiresistant profile and increased tolerance to the metals tested were Pseudomonas and Ochrobactrum. The results of this study may contribute to future research and the revision and regulation of legislation on sewage sludge reuse in soils.
ResumoO efluente proveniente dos processos industriais, quando não tratado, pode gerar vários danos a natureza e comprometer a saúde da população. Assim, o presente estudo realizado na estação de tratamento de efluentes de uma Agroindústria do Meio Oeste de Santa Catarina, teve por objetivo: realizar o levantamento dos dados referentes aos parâmetros físico-químicos (DBO, DQO, pH, Nitrogênio Total, Fósforo Total, Sólidos Sedimentáveis e Sólidos Suspensos Totais) de dois pontos do processo, antes e após o tratamento biológico; avaliar a eficiência do tratamento e as características do floco biológico (diversidade e ocorrência) relacionando-a aos dados físico-químicos. A avaliação da eficiência da estação bem como a análise microscópica do lodo foi realizada no período de agosto a outubro do ano de 2015, contabilizando dez análises. Conforme dados físico-químicos os valores médios, saída do . A eficiência média geral dos parâmetros variou de 76,30% a 96,23%. Nas observações, verificou-se
The search for alternative sources of energy, such as biodiesel, has been stimulated, since this biofuel is highly susceptible for biodegradation and has low toxicity, thus, reducing the impact in ecosystems. The objective of this study was to select a bacterial consortium with potential for degrading diesel/biodiesel blends (B20) obtained from areas contaminated with hydrocarbons/esters. In order to evaluate the biodegrability of the blend, six enzyme assays were conducted: alkane hydroxylase, Catechol 1,2-dioxygenase, Catechol 2,3-dioxygenase, Protocatechol 3,4-dioxygenase, ρ-NPA hydrolysis (esterase), and release of fatty acids through titration (lipase), with estimative of total protein and biosurfactant production (surface tension measurement and emulsifying index E(24)). The best results obtained allowed the selection of four bacteria isolates (Bacillus megaterium, Bacillus pumilus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia) for compiling a consortium, which will be used for bioaugmentation strategies in soils contaminated with these fuels. This consortium exhibited high potential for biodegradation of biodiesel, and might be an efficient alternative for cleaning up these contaminated environments.
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