Determination of key events in mouse hepatocyte maturation at the single-cell level.

Hepatocytes, the liver's predominant cells, perform numerous essential biological functions. However, crucial events and regulators during hepatocyte maturation require in-depth investigation. In this study, we performed single-cell RNA sequencing (scRNA-seq) and single-nucleus RNA sequencing (snRNA-seq) to explore the precise hepatocyte development process in mice. We defined three maturation stages of postnatal hepatocytes, each of which establishes specific metabolic functions and exhibits distinct proliferation rates. Hepatic zonation is gradually formed during hepatocyte maturation. Hepatocytes or their nuclei with distinct ploidies exhibit zonation preferences in distribution and asynchrony in maturation. Moreover, by combining gene regulatory network analysis with in vivo genetic manipulation, we identified critical maturation- and zonation-related transcription factors. This study not only delineates the comprehensive transcriptomic profiles of hepatocyte maturation but also presents a paradigm to identify genes that function in the development of hepatocyte maturation and zonation by combining genetic manipulation and measurement of coordinates in a single-cell developmental trajectory.

[Distribution and Treatment of Antibiotics in Typical WWTPs in Small Towns in China].

As a new, persistent pollutant in the environment, antibiotics are one of the most important pollutants in sewage treatment plants. The objective of this work was to investigate the concentration distribution and removal efficiency of antibiotics for three typical wastewater treatment technologies applied in small towns (CASS, A2/O, and Orbal oxidation ditch) using solid phase extraction-liquid chromatography-tandem mass spectrometry. Sixteen typical antibiotics, including four tetracyclines, three ß-lactams, four macrolides, three quinolones, and two sulfonamides, were analyzed in the influent and effluent. In addition, the relationship between the presence of antibiotics and the basic water quality (NH4+-N, TN, COD, pH, etc.) in the WWTPs was analyzed. The results showed that ofloxacin (OFX) and norfloxacin (NOR) were the main antibiotics in the WWTPs in this study. However, the concentrations of these two antibiotics in the effluent were low, indicating effective antibiotic removal efficiency. The antibiotic removal efficiency was higher than 60% in five of the WWTPs. Compared with the A2/O process, the CASS and Orbal oxidation ditch technologies resulted in higher removals of most of the antibiotics. In addition, the CASS and A2/O processes worked best for the removal of ß-lactam [ampicillin (AMP) and penicillin (PCN)], quinolones (ENR, NOR, and OFX), and macrolide (CLR), while the Orbal oxidation ditch worked best for the removal of tetracyclines (TC and OTC) and sulfonamides [sulfadiazine (SD)]. The correlation between antibiotic concentration and the basic parameters of water quality (NH4+-N, TN, COD, pH, etc.) was analyzed, and it was found that the water quality parameters had some effect on the concentration of antibiotics. With higher concentrations of the basic water quality parameters, higher the concentration of erythromycin (EM), roxithromycin (ROX), 4-epi-Tetracycline (E-TC), clarithromycin (CLR), ciprofloxacin (CIP), ofloxacin (OFX), epioxytetracycline (E-OTC), tetracyclines (TC), oxytetracycline (OTC), and norfloxacin (NOR) were observed. In summary, it is important to ensure the stable operation of small town WWTPs to reduce the ecological risk of antibiotics.

[Emission of CH4, N2O and NH3 from vegetable field applied with animal manure composts].

Greenhouse gas (GHG) emission from vegetable land is of great concern recently because agriculture land is one of the major sources contributing to global GHG emission. In this study, an experiment of Lactuca sativa L. land applied with different animal manure composts was carried out in a greenhouse vegetable land located in the surburb of Beijing to monitor the emission of GHG (CH4 and N2O) and ammonia in situ, and to analyze the affecting factors of GHG and ammonia emission. Results showed that the emission factors (EFs) of CH4 from Treatment NRM, RM and CF were 0.2%, 0.027% and 0.004%, respectively,the EFs of N2O from these three treatments were 0.18%, 0.63% and 0.74%, respectively, and the EFs of ammonia were 2.00%, 3.98% and 2.53%, respectively. CH4 emission flux was significantly affected by soil temperature and humidity, while N2O emission flux was related to soil temperature, surface temperature and humidity. The emission fluxes of CH4, N2O and NH3 were significantly affected by soil moisture, but there was little relation between CH4, N2O and NH3 emissions and the ambient temperature in the greenhouse.

[Effects of turning frequency on emission of greenhouse gas and ammonia during swine manure windrow composting].

It is of great concern for greenhouse gas (GHG) reduction of animal manure management in China due to the extreme lack of GHG emission data during animal manure composting. Therefore, the purpose of this study was to investigate the effects of turning frequency on the emission of GHG (CH4, N2O) and NH3 during swine manure windrow composting through on-site observation of a full scale test in Beijing. Results showed that the turning frequency had significant impacts on the emission of both GHG and ammonia, which did not only increase the emission of GHG and ammonia, but also increased the percentage of total nitrogen loss due to NH3 emission (42.2% at turning once a week and 70.05% at turning twice a week, respectively). Compared with N2O emission, CH4 emission was the main contributor to Global Warming Potentials (GWPs).

[Nutrients conservation of N & P and greenhouse gas reduction of N2O emission during swine manure composting].

Nitrogen loss and greenhouse gas (N2O) emission occur during animal manure composting, as well as phosphorus loss caused by runoff during land application of animal manure compost. Therefore, the purposes of this study were to simultaneously conserve nutrients of nitrogen & phosphorus and reduce N2O emission during animal manure composting using modified salts which are made from industrial solid waste. Experiments of in-vessel swine manure composting at lab-scale were carried out to investigate and compare effects of modified red-mud (MR) and modified forsterite (MF) as additives on nutrients conservation and greenhouse gas (N2O) reduction. As far as the nitrogen loss calculated on the basis of ammonia and nitrous oxide is concerned, the least nitrogen loss at only 6.38% of TKN occurred in the swine manure composting with MF addition at pH 7.0 +/- 0.2, compared with those of MR addition at pH 5.0 +/- 0.2 at 11.07% of TKN and the control at 14.68% of TKN, respectively. The best results of ammonia and nitrous oxide mitigation during swine manure composting were the treatments with MR addition and MF addition, which nitrogen losses were at 2.13% of TKN as NH3 and 0.65% of TKN, respectively. These results clearly showed that the modified salt additives from red-mud and forsterite were useful for saving nitrogen and reducing N2O emission. Moreover, the contents of soluble orthophosphate in swine manure compost with the addition of both modified salts were less than that of the control, which is helpful to reduce P loss during land application of swine manure compost.

[Impacts on N and P conservation during swine manure composting with different modified metal-salts addition].

Batch experiments were carried out by using mixed-level uniform design method U6 (692) x 3) to investigate the effect of the addition of different metal-salts at 20%, 40% and 60% of NT, respectively, including modified red-mud (MR) at pH 5.0 +/- 0.2 and 7.0 +/- 0.2, respectively, modified forsterite (MF) at pH 7.0 +/- 0.2, and MgSO4 on nitrogen and phosphorus conservation during swine manure composting. The results showed that the optimum effect of N saved occurred at No. 5 experiment (20%, MF, day 17) and No. 3 experiment (40%, MgSO4, day 10). Meanwhile, the P conservation of experiments with metal salts addition was better than that of the control, and the No. 6 experiment (20%, MR with pH =5, day 21) was the highest on TP conservation, with the lowest ratio of PO4(3-) -P/TP.

[Comparison of bioremediation of polycyclic aromatic hydrocarbons (PAHs) contaminated soil by composting in the spring and winter].

In this study, lab-scale bioremediation experiments of soil contaminated by polycyclic aromatic hydrocarbon (PAHs) with aerated composting were compared in the Spring and Winter. Results showed that PAHs degradation rate in the winter was higher than that in the spring, and the total PAHs degradation rates were over 70% for both Pile 1 (the dry weight ratio of soil, swine manure and sawdust as 1: 1: 1) and Pile 2 (the dry weight ratio of soil, swine manure and sawdust as 1: 3: 1), but the PAHs degradation rate of Pile 1 as 74.61% was higher than that of Pile 2 the degradation rates of low, middle, high benzene-ring types PAHs were 66.46%, 79.12%, 75.88%, respectively. After composting most of kinds of PAHs contents in soil were less than 1 000 microg/kg (dry weight) except BbF, for example, BbF contents of these two piles in the Spring, 25 000 microg/kg and 20 000 microg/kg, respectively, were much higher than those in the winter experiments, both less than 5 000 microg/kg. The first reaction order model was used to simulate degradation of PAHs during composting, and results showed that the model was fitted better in winter (R2 > 0.6) than in spring, and the half-life of PAHs degradation in winter was about 13 d.