The diversity and abundance of ammonia-oxidizing bacteria was investigated in three different types of horizontal subsurface flow constructed wetlands, reed (Phragmites australis)/gravel bed (W1), hybrid vegetation {reed, cattail (Typha latifolia), bulrush (Scirpus validus)}/gravel bed (W2) and reed/hybrid substrates bed (gravel, zeolite, slag) (W3). The investigation of community structures of ammonia-oxidizing bacteria revealed that the types of macrophytes , substrate and space distributions had significant influence on the microbial community. The ammonia-oxidizing bacteria detected were all inculturable, and belonged to Nitrosomonas spp.
The removal of ammonia nitrogen from the polluted water was investigated in three different types of horizontal subsurface flow constructed wetlands, reed (Phragmites australis)/gravel bed (W1), hybrid vegetation {reed, cattail (Typha latifolia), bulrush (Scirpus validus)}/gravel bed (W2) and reed/hybrid substrates (gravel, zeolite, slag) bed (W3). At HRT of 28 d, NH3-N removal efficiencies of W1, W2 and W3 were-130%98%, -120%98% and 21%98% respectively throughout the whole year. The results showed that zeolite and slag contributed to higher NH3-N removal than gravel, especially in winter, and that cattail and bulrush did not show significant influences on NH3-N removal. The ranges of NH3-N removal rates were-2.332.14, -2.272.33 and 0.082.52 g·m-3·d-1 respectively under HRT of 2 d. NH3-N removal rates of W1 and W2 were much more affected by temperature than that of W3, which was due to the adsorption/desorption of zeolite.
Denitrification is strongly dependent on carbon quantity and quality in most constructed wetlands (CWs), and pH may be a key factor in determining the supply of available carbon source (ACS) in the pre-treatment of external plant biomass. In this study, three bath CWs were designed, and were fed with nitrate-dominated water to investigate nitrate removal affected by external cattail litter with different pH pre-treatment (pH = 7.0, 10.0, 12.0). During the experiment, higher nitrate removal was observed in the wetland using pH12.0 pre-treatment litter leachate as the carbon source. Strong alkaline fermentation at ambient temperature can be considered as a sustainable technology for wetland plant litter pre-treatment.
Inhibition of immunocyte infiltration and activation has been proven to effectively ameliorate hepatic inflammation and fibrosis in nonalcoholic steatohepatitis (NASH). Paired immunoglobulin-like receptor B (PirB) and its human orthologue receptor, leukocyte immunoglobulin-like receptor B (LILRB2), are immune-inhibitory receptors with unknown roles in NASH. Here, we demonstrate that PirB/LILRB2 regulates the migration of macrophages in NASH pathogenesis and fibrogenesis by binding to its NASH-associated ligand angiopoietin-like protein 8 (ANGPTL8). Mechanistically, PirB facilitates the ANGPTL8-induced infiltration of monocyte-derived macrophages (MDMs) into the liver by regulating the phosphorylation of P38, AKT, and P65. Hepatocyte-specific knockout of its ligand ANGPTL8 reduces MDM infiltration and resolves lipid accumulation and fibrosis progression in the livers of NASH mice. In addition, PirB−/− bone marrow (BM) chimaeras abrogated ANGPTL8-induced MDM migration to the liver. PirB ectodomain protein can ameliorate the lipid accumulation inflammatory response and fibrosis of NASH by sequestering ANGPTL8. Furthermore, LILRB2-ANGPTL8-axis-associated MDM migration and inflammatory activation are also observed in human peripheral blood monocytes. Taken together, our findings reveal a novel role of PirB/LILRB2 in NASH pathogenesis and identify PirB/LILRB2-ANGPTL8 signalling as a potential target for the management or treatment of NASH.
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