Project description:Lack of non-invasive diagnostic tools and effective therapies constitute two of the major hurdles for a bona fide treatment against non-alcoholic steatohepatitis (NASH) progression and/or regression of nonalcoholic fatty liver disease (NAFLD). Nitro-oleic acid (OA-NO2) has been proven effective in multiple experimental models of inflammation and fibrosis. Thus, the potential benefit of in vivo administration of OA-NO2 to treat advanced NAFLD was studied in a model of long-term NASH diet-induced liver damage. Non-invasive imaging (e.g. photoacustic-ultrasound (PA-US)) was pursued to establish advanced experimental NASH in mice in which both steatosis and fibrosis were diagnosed prior experimental OA-NO2 therapy. CLAMS and NMR-based analysis demonstrates that OA-NO2 improves body composition and energy metabolism and inhibits hepatic triglyceride accumulation. PA-US imaging revealed a robust inhibition of liver steatosis and fibrosis by OA-NO2. RNA-sequencing analysis uncovered inflammation and fibrosis as major pathways suppressed by OA-NO2 administration, as well as regulation of lipogenesis and lipolysis pathways, with a robust inhibition of SREBP1-dependent lipogenic gene expression by OA-NO2. Global liver transcriptome in response to OA-NO2 was confirmed in vivo and in isolated hepatocytes. These results were further supported by histological analysis and quantification of lipid accumulation, lobular inflammation (F4/80 staining) and fibrosis (collagen deposition, αSMA staining) as well as established parameters of liver damage (ALT). In vitro studies indicate that OA-NO2 inhibits TG biosynthesis and accumulation in hepatocytes and inhibits fibrogenesis in human stellate cells. Taken together, OA-NO2 improve steatohepatitis and fibrosis and may constitute an effective therapeutic approach against advanced NAFLD that warrants further clinical evaluation.
Project description:In the present study, a distinct transcriptome regulated by NO2-CLA was revealed in primary human coronary artery endothelial cells (HCAECs) through RNA sequencing. Differential gene expression and pathway enrichment analysis identified numerous regulatory networks of cell cycle regulation, inflammation and redox responses, nitric oxide biosynthesis, hypoxia and chaperones in response to NO2-CLA, suggesting potent and diverse effects of NO2-CLA on cellular processes.
Project description:In this study, the A-NO2- sensitivity of mucA22 mutant bacteria vs. a genome sequence-confirmed mucA deletion (∆mucA) mutant was determined. The ∆mucA is surprisingly more resistant to A-NO2- than mucA22 bacteria. The genes responsible for the disposal of nitric oxide (NO), a by-product of A-NO2-, were found to be near wild-type levels in the ∆mucA mutant yet were dramatically reduced in the mucA22 mutant.
Project description:Four-week-old Arabidopsis thaliana (Col-0) plants were fumigated for 1 h with 10 parts per million (ppm) nitrogen dioxide (NO2) to analyse leaf transcriptome changes induced by this air pollutant relative to air-fumigated control plants.
Project description:The aim of the present work was to maximise NO2- conversion over NO3- reduction coupled with complete sulphide (HS-) oxidation, by the selective control of influent S/N ratio and sludge retention time (SRT). A 2.5-L chemostat was operated for 115 days and three operational phases were tested at decreasing SRT of 40, 23 and 13 h, testing S/N ratios in the range of 0.5-1 gS/gN. Successful sulphide-driven PAD was achieved and lead to average NO2- conversion efficiencies as high as 77±17% at all the conditions tested, with the highest value of 99% at the lowest S/N of 0.58 gS/gN and SRT of 23 h. Respirometric tests showed that NO3- uptake rate was stable at 90±10 mgN/gVSS/h, either when NO3- was present as sole electron acceptor or at NO2- levels as high as 120 mgN/l; on the contrary, NO2- uptake rates were very sensitive to the applied conditions. Metabarcoding analyses revealed that the microbial community was highly enriched in Sulphur Oxidizing Bacteria (SOB>80%) and strict and stable S-limiting conditions appeared to favour Thiobacillus over Sulfurimonas genus. A preliminary assessment of N2O potential emission was also performed. To the best of our knowledge, this is the first work evaluating the synergic effect of SRT and influent S/N ratio on nitrite accumulation in highly SOB-enriched systems and the NO2- conversion efficiencies achieved are among the highest reported in literature.
Project description:Wastewater treatment plants use a variety of bioreactor types and configurations to remove organic matter and nutrients. Little is known regarding the effects of different configurations and within-plant immigration on microbial community dynamics. Previously, we found that the structure of ammonia-oxidizing bacterial (AOB) communities in a full-scale dispersed growth activated sludge bioreactor correlated strongly with levels of NO2- entering the reactor from an upstream trickling filter (Wells et al 2009). Here, to further examine this puzzling association, we profile within-plant microbial biogeography (spatial variation) and test the hypothesis that substantial microbial immigration occurs along a transect (raw influent, trickling filter biofilm, trickling filter effluent, and activated sludge) at the same full-scale wastewater treatment plant. AOB amoA gene abundance increased >30-fold between influent and trickling filter effluent concomitant with NO2- production, indicating unexpected growth and activity of AOB within the trickling filter. Nitrosomonas europaea was the dominant AOB phylotype in trickling filter biofilm and effluent, while a distinct ‘Nitrosomonas-like’ lineage dominated in activated sludge. Prior time series indicated that this ‘Nitrosomonas-like’ lineage was dominant when NO2- levels in the trickling filter effluent (i.e., activated sludge influent) were low, while N. europaea became dominant in the activated sludge when NO2- levels were high. This is consistent with the hypothesis that NO2- production may co-occur with biofilm sloughing, releasing N. europaea from the trickling filter into the activated sludge bioreactor. Phylogenetic microarray (PhyloChip) analyses revealed significant spatial variation in taxonomic diversity, including a large excess of methanogens in the trickling filter relative to activated sludge and attenuation of Enterobacteriaceae across the transect, and demonstrated transport of a highly diverse microbial community via the trickling filter effluent to the activated sludge bioreactor. Our results provide compelling evidence that substantial immigration between coupled process units occurs and may exert significant influence over microbial community dynamics within staged bioreactors.
Project description:Enrichments with labeled CH4 and NO2 were conducted to test microbial community correlations and constrain potential metabolic interactions between methanotrophs and other one-carbon utilizing microorganisms under low O2 conditions