Comparative metagenome of a stream impacted by the urbanization phenomenon

Abstract Rivers and streams are important reservoirs of freshwater for human consumption. These ecosystems are threatened by increasing urbanization, because raw sewage discharged into them alters their nutrient content and may affect the composition of their microbial community. In the present study, we investigate the taxonomic and functional profile of the microbial community in an urban lotic environment. Samples of running water were collected at two points in the São Pedro stream: an upstream preserved and non-urbanized area, and a polluted urbanized area with discharged sewage. The metagenomic DNA was sequenced by pyrosequencing. Differences were observed in the community composition at the two sites. The non-urbanized area was overrepresented by genera of ubiquitous microbes that act in the maintenance of environments. In contrast, the urbanized metagenome was rich in genera pathogenic to humans. The functional profile indicated that the microbes act on the metabolism of methane, nitrogen and sulfur, especially in the urbanized area. It was also found that virulence/defense (antibiotic resistance and metal resistance) and stress response-related genes were disseminated in the urbanized environment. The structure of the microbial community was altered by uncontrolled anthropic interference, highlighting the selective pressure imposed by high loads of urban sewage discharged into freshwater environments.

Identification of dysregulated microRNA expression and their potential role in the antiproliferative effect of the essential oils from four different Lippia species against the CT26.WT colon tumor cell line

ABSTRACT In spite of advances in colorectal cancer treatments, approximately 1.4 million new global cases are estimated for 2015. In this sense, Brazilian plant diversity offers a multiplicity of essential oils as prospective novel anticancer compounds. This study aimed to evaluate the antiproliferative effect of the essential oils from four Lippia species in CT26.WT colon tumor cells, as a measurement of cell cycle phase distribution and microRNA expression. CT26.WT showed cell cycle arrest at G2/M phase after treatment with 100 µg/ml of Lippia alba (Mill.) N.E.Br. ex Britton & P. Wilson, Lippia sidoides Cham., and Lippia lacunosa Mart. & Schauer, Verbenaceae, essential oils and, at the same concentration, Lippia rotundifolia Cham. essential oil caused an augment of G0/G1 phase. The miRNA expression profiling shows change of expression in key oncogenic miRNAs genes after treatment. Our findings suggest growth inhibition mechanisms for all four essential oils on CT26.WT cells involving direct or indirect interference on cell cycle arrest and/or oncogenic miRNAs expression.

Distribution, detection of enterotoxigenic strains and antimicrobial drug susceptibility patterns of Bacteroides fragilis group in diarrheic and non-diarrheic feces from Brazilian infants

Despite the importance of gastrointestinal diseases and their global distribution, affecting millions of individuals around the world, the role and antimicrobial susceptibility patterns of anaerobic bacteria such as those in the Bacteroides fragilis group (BFG) are still unclear in young children. This study investigated the occurrence and distribution of species in the BFG and enterotoxigenic strains in the fecal microbiota of children and their antimicrobial susceptibility patterns. Diarrheic (n=110) and non-diarrheic (n=65) fecal samples from children aged 0-5 years old were evaluated. BFG strains were isolated and identified by conventional biochemical, physiological and molecular approaches. Alternatively, bacteria and enterotoxigenic strains were detected directly from feces by molecular biology. Antimicrobial drug susceptibility patterns were determined by the agar dilution method according to the guidelines for isolated bacteria. BFG was detected in 64.3 percent of the fecal samples (55 percent diarrheic and 80.4 percent non-diarrheic), and 4.6 percent were enterotoxigenic. Antimicrobial resistance was observed against ampicillin, ampicillin/sulbactam, piperacillin/tazobactam, meropenem, ceftriaxone, clindamycin and chloramphenicol. The data show that these bacteria are prevalent in fecal microbiota at higher levels in healthy children. The molecular methodology was more effective in identifying the B. fragilis group when compared to the biochemical and physiological techniques. The observation of high resistance levels stimulates thoughts about the indiscriminate use of antimicrobial drugs in early infancy. Further quantitative studies are needed to gain a better understanding of the role of these bacteria in acute diarrhea in children.