38 research outputs found

    Community shift of ammonia-oxidizing bacteria along an anthropogenic pollution gradient from the Pearl River Delta to the South China Sea

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    The phylogenetic diversity and abundance of ammonia-oxidizing beta-proteobacteria (beta-AOB) was analyzed along an anthropogenic pollution gradient from the coastal Pearl River Delta to the South China Sea using the ammonia monooxygenase subunit A (amoA) gene. Along the gradient from coastal to the open ocean, the phylogenetic diversity of the dominant genus changed from Nitrosomonas to Nitrosospira, indicating the niche specificity by these two genera as both salinity and anthropogenic influence were major factors involved. The diversity of bacterial amoA gene was also variable along the gradient, with the highest in the deep-sea sediments, followed by the marshes sediments and the lowest in the coastal areas. Within the Nitrosomonas-related clade, four distinct lineages were identified including a putative new one (A5-16) from the different sites over the large geographical area. In the Nitrosospira-related clade, the habitat-specific lineages to the deep-sea and coastal sediments were identified. This study also provides strong support that Nitrosomonas genus, especially Nitrosomonas oligotropha lineage (6a) could be a potential bio-indicator species for pollution or freshwater/wastewater input into coastal environments. A suite of statistical analyses used showed that water depth and temperature were major factors shaping the community structure of beta-AOB in this study area

    Miravirsen dosing in chronic hepatitis C patients results in decreased microRNA-122 levels without affecting other microRNAs in plasma

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    Background MicroRNA-122 (miR-122) is an important host factor for hepatitis C virus replication. Administration of miravirsen, an anti-miR-122 oligonucleotide, resulted in a dose dependent and prolonged decrease in HCV RNA levels in chronic hepatitis C patients. Aim To assess the plasma level of various miRNAs in patients dosed with miravirsen. Methods We included 16 of 36 chronic hepatitis C patients who received five injections of either 3 mg/kg (n = 4), 5 mg/kg (n = 4), 7 mg/kg (n = 4) miravirsen or placebo (n = 4) over a 4-week period in a double-blind, randomised phase 2a study. Plasma levels of 179 miRNAs were determined by qPCR and compared between patients dosed with miravirsen or placebo. Results Median plasma miR-122 level at baseline in patients receiving miravirsen was 3.9 x 10(3) compared to 1.3 x 10(4) copies/4 mu L in placebo-dosed patients (P = 0.68). At week 1, 4, 6 and 10/12, patients dosed with miravirsen had respectively a median 72-fold, 174-fold, 1109-fold and 552-fold lower expression of miR-122 than at baseline (P = 0.001, as compared to patients receiving placebo). At week 4 of dosing, miRNA-profiling demonstrated a significant lower expression of miR-210 and miR-532-5p compared to baseline (3.0 and 4.7-fold lower respectively). However, subsequent longitudinal analysis showed no significant differences in miR-210 and miR-532-5p plasma levels throughout the study period. Conclusions We demonstrated a substantial and prolonged decrease in plasma miR-122 levels in patients dosed with miravirsen. Plasma levels of other miRNAs were not significantly affected by antagonising miR-122
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