Metagenomic insights into the influence of pH on antibiotic removal and antibiotic resistance during nitritation: Regulations on functional genus and genes.

The changes in pH and the resulting presence of free nitrous acid (FNA) or free ammonia (FA) often inhibit antibiotic biodegradation during nitritation. However, the specific mechanisms through which pH, FNA and FA influence antibiotic removal and the fate of antibiotic resistance genes (ARGs) are not yet fully understood. In this study, the effects of pH, FNA, and FA on the removal of cefalexin and amoxicillin during nitritation were investigated. The results revealed that the decreased antibiotic removal under both acidic condition (pH 4.5) and alkaline condition (pH 9.5) was due to the inhibition of the expression of amoA in ammonia-oxidizing bacteria and functional genes (hydrolase-encoding genes, transferase-encoding genes, lyase-encoding genes, and oxidoreductase-encoding genes) in heterotrophs. Furthermore, acidity was the primary inhibitor of antibiotic removal at pH 4.5, followed by FNA. Antibiotic removal was primarily inhibited by alkalinity at pH 9.5, followed by FA. The proliferation of ARGs mediated by mobile genetic element was promoted under both acidic and alkaline conditions, attributed to the promotion of FNA and FA, respectively. Overall, this study highlights the inhibitory effects of acidity and alkalinity on antibiotic removal during nitritation.

Effects of different oxidants on the behaviour of microplastic hetero-aggregates.

Microplastic hetero-aggregates are stable forms of microplastics in the aqueous environment. However, when disinfecting water containing microplastic hetero-aggregates, the response of them in water to different oxidizing agents and the effect on water quality have not been reported. Our results showed that Ca(ClO)2, K2S2O8, and sodium percarbonate (SPC) treatment could lead to the disaggregation of microplastic hetero-aggregates as well as a rise in cell membrane permeability, which caused a large amount of organic matter to be released. When the amount of oxidant dosing is insufficient, the oxidant cannot completely degrade the released organic matter, resulting in DOC, DTN, DTP and other indicators being higher than before oxidation, thus causing secondary pollution of the water body. In comparison, K2FeO4 can purify the water body stably without destroying the microplastic hetero-aggregates, but it only weakly inhibits the toxic cyanobacteria Microcystis and Pseudanabaena, which may cause cyanobacterial bloom as well as algal toxin and odorant contamination in practical application. Compared with the other oxidizers, K2S2O8 provides better inhibition of toxic cyanobacteria and has better ecological safety. Therefore, when treating microplastic-containing water bodies, we should consider both water purification and ecological safety, and select appropriate oxidant types and dosages to optimize the water treatment.

The synergistic mechanism of ß-lactam antibiotic removal between ammonia-oxidizing microorganisms and heterotrophs.

Nitrifying system is an effective strategy to remove numerous antibiotics, however, the contribution of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA) and heterotrophs for antibiotic removal are still unclear. In this study, the mechanism of ß-lactam antibiotic (cefalexin, CFX) removal was studied in a nitrifying sludge system. Results showed that CFX was synergistically removed by AOB (Nitrosomonas, played a major role) and AOA (Candidatus_Nitrososphaera) through ammonia monooxygenase-mediated co-metabolism, and by heterotrophs (Pseudofulvimonas, Hydrogenophaga, RB41, Thauera, UTCFX1, Plasticicumulans, Phaeodactylibacter) through antibiotic resistance genes (ARGs)-encoded ß-lactamases-mediated hydrolysis. Regardless of increased archaeal and heterotrophic CFX removal with the upregulation of amoA in AOA and ARGs, the system exhibited poorer CFX removal performance at 10 mg/L, mainly due to the inhibition of AOB. This study provides new reference for the important roles of heterotrophs and ARGs, opening the possibilities for the application of ARGs in antibiotic biodegradation.

4-[1-Ethyl-1-methylhexy]-phenol induces apoptosis and interrupts Ca2+ homeostasis via ROS pathway in Sertoli TM4 cells.

Biological effect of an individual nonylphenol (NP) isomer extremely relies upon the side chain structure. This research was designed to evaluate the impact of NP isomer, 4-[1-ethyl-1-methylhexy]-phenol (NP65), on Sertoli cells in vitro. Sertoli TM4 cells were exposed to various concentration (0, 0.1, 1, 10, or 20 µM) of NP65 for 24 h, and the outcomes indicated that treatment of NP65 induced reactive oxygen species (ROS) generation, oxidative stress, and apoptosis for Sertoli TM4 cells. In addition, it was found that NP65 exposure affected homeostasis of Ca2+ in Sertoli TM4 cells by increasing cytoplasm [Ca2+]i, inhibiting Ca2+-ATPase activity and decreasing cyclic adenosine monophosphate (cAMP) concentration. Pretreatment with ROS scavenger, N-acetylcysteine (NAC), attenuated NP65-induced oxidative stress as well as apoptosis for TM4 cells. Furthermore, NAC blocked NP65-induced disorders of Ca2+ homeostasis by attenuating the growth of intracellular [Ca2+]i and the inhibition of Ca2+-ATPase and cAMP activities. Thus, we have demonstrated that NP65 induced apoptosis as well as acted as a potent inhibitor of Ca2+-ATPase activity and resulted in disorder of Ca2+ homeostasis in Sertoli TM4 cells; ROS participated in the process. Our results supported the view that oxidative stress acted an essential role within the development of apoptosis and Ca2+ overload in TM4 cells as a consequence of NP65 stimulation.

Downregulation of Circular RNA PSEN1 ameliorates ferroptosis of the high glucose treated retinal pigment epithelial cells via miR-200b-3p/cofilin-2 axis.

Ferroptosis is a form of programmed cell death that participates in the progression of numerous diseases. Long noncoding RNAs (lncRNAs) are dysregulated in diabetic retinopathy (DR). However, the role of lncRNAs in DR-induced ferroptosis is unclear. Adult retinal pigment epithelial cell line-19 (ARPE19) cells were treated with a high concentration of glucose (high glucose, HG) to mimic DR in vitro. The intracellular contents of glutathione, malondialdehyde, and ferrous ions were analyzed using the corresponding kits. The MTT assay was performed to measure the cell survival rate, and cell death was determined using propidium iodide and terminal deoxynucleotidyl transferase dUTP nick end labeling staining assays. Western blotting was conducted to detect the protein levels of GPX4, SLC7A11, and TFR1. The targeting relationships were verified using luciferase reporter and RNA pull-down assays. circ-PSEN1 was upregulated in HG-treated ARPE19 cells and showed high resistance to RNase R and Act D. Inhibition of circ-PSEN1 in ARPE19 cells ameliorated the ferroptosis induced by HG was ameliorated, as evidenced by changes in the ferroptosis-related biomarkers/genes and decreased cell death. Subsequently, circ-PSEN1 acted as a sponge for miR-200b-3p. Inhibition of miR-200b-3p partially reversed the effects of circ-PSEN1 on ferroptosis. Furthermore, cofilin-2 (CFL2) was the target gene of miR-200b-3p, and it abrogated the inhibitory effect of miR-200b-3p on ferroptosis. Taken together, the findings indicate that knockdown of circ-PSEN1 can mitigate ferroptosis of ARPE19 cells induced by HG via the miR-200b-3p/CFL2 axis.

Evaluation of the long-term effect of foldable capsular vitreous bodies in severe ocular rupture.

AIM: To evaluate the long-term effect of foldable capsular vitreous body (FCVB) in the treatment of severe ocular rupture to provide a practical basis for clinical selection. METHODS: A total of 26 patients (26 eyes), 23 men and 3 women, with severe ocular rupture who underwent FCVB implantation between March 2018 and September 2018 were retrospectively analysed. All open ocular wounds located in zone III, with preoperative visual acuity grade IV and above (Snellen less than 4/200). The best corrected visual acuity (BCVA), intraocular pressure (IOP), cornea, anterior chamber, iris, lens, choroid, and retina were evaluated before and after the surgery. The subjective feeling and the location of FCVB were also assessed. RESULTS: The average age of the 26 patients was 36y (20-60y). Postoperative follow-up was from 10 to 14mo. At the end of follow up, BCVA was light perception (LP) in 10 cases, no light perception (NLP) in 13 cases, hand motions (HM) in 3 cases. IOP was 11±5 mm Hg. Corneal degeneration was in 3 cases and corneal endothelial dystrophy was in 7 cases. Shallow anterior chamber was in 8 cases and hyphema was in 8 cases. Organized membrane in the pupil was in 14 cases. Epiphora occurred in 3 cases. FCVB drainage tube exposed in 3 cases. All FCVBs were in their normal location and no rejection occurred. CONCLUSION: FCVB implantation is a long-term effective treatment and may provide a practical selection for severe ocular rupture.

The adsorption efficiency of nitrogen and phosphorus by in-situ remediation of modified sediment composite material.

Dredged sediment can occupy a large amount of land area, resulting in waste of land resources, and high disposal costs. In response to the problem, this work calcinates and modified the sediment and compounds it with the modified water purification plant sludge, zeolite powder, and bentonite. This is used as a covering material to inhibit the release of nitrogen (N) and phosphorus (P) in the sediment. The results showed that sediment modified composite material covering effectively reduces the release of nitrogen (N) and phosphorus (P) in the sediment, especially the release of P. When the thickness of the covering layer is 3 cm, the reduction rate of total N, NH4+-N, and total P in the overlying water by the modified composite material of sediment is 61.58, 79.59, and 70.34%, respectively. It can be seen that the covering material has a significant effect on the control of the release of N and P in the sediment. Additionally, the reduction of nutrients in the overlying water can overcome the negative effects of temperature rise in controlling the release of N and P in the sediment.

Structural and microbial evidence for different soil carbon sequestration after four-year successive biochar application in two different paddy soils.

Application of biochar (BC) derived from rice straw has generated increasing interest in long-term storage of soil organic carbon (SOC), however its carbon (C) sequestration potential vary widely among agricultural soils despite the same BC dose used. These discrepancies in the ability of soils to sequester C after BC application are poorly understood. Metabolic quotient (qCO2) is a reflection of "microbial efficiency" and linked to SOC turnover across ecosystems. Therefore, we investigated the SOC sequestration and qCO2 in a Yellow River alluvium paddy soil (YP) and a quaternary red clay paddy soil (QP) under rice-wheat annual rotation following 4-year of BC application rate of 11.3 Mg ha-1 per cropping season. BC application consistently brought 65.3 Mg C ha-1 into the soils over 4-year experimental period but increased SOC by 57.6 Mg C ha-1 in YP and 64.5 Mg C ha-1 in QP. Calculating SOC mass balance showed 11.7% of BC-C losses from YP and only 1.16% from QP. BC application stimulated the G+ bacterial, fungi, and actinomycetes by increasing O-alkyl C content in YP, while decreased the same microorganisms by decreasing anomeric C-H content in QP. Importantly, higher clay and amorphous Fe (Feo) contents in QP after BC application protected SOC from further decomposition, which in turn decreased microorganisms and resulted in higher SOC sequestration than YP. Our results indicated that soil properties controlled the extent of SOC sequestration after BC application and site-specific soil properties must be carefully considered to maximize long-term SOC sequestration after BC application.

Removal of organic pollutants by contact oxidation of biological carbon sludge.

A pilot-scale (5 m3 /day) study was conducted for the treatment of micro-polluted low-turbidity water using a biological contact oxidation high-density sedimentation tank system with biochar sludge. First, the best operating conditions were found through system debugging; then, biological characteristics were investigated during system debugging; and finally, the performance in terms of pollutant elimination was investigated. The carbon sludge tank biomass was stable, which provided good stability for the removal of organic matter in raw water. The average reduction in absorbance of UV254 and total organic carbon were 36.71% and 29.63%, respectively, when compared with conventional coagulation. The adsorption and degradation of the mixture comprising carbon and sludge played an important role in removing organic pollutants; most of the humic and fulvic acid content of the water was removed during the coagulation processes. PRACTITIONER POINTS: The contact oxidation of biological carbon sludge system can effectively treat low-turbidity water. The extracellular polymeric substances and the filamentous bacteria connecting the structure provided good settling for the carbon sludge mixture. The adsorption and degradation of the mixture comprising carbon and sludge played an important role in removing organic pollutants. With the carbon sludge reflux, organic matter with molecular weight >30K and 10K-3K was greatly reduced. The contact oxidation of biological carbon sludge system was successful in reducing the concentrations of DBPs and their precursors.

Use of Nitrogen Isotope To Determine Fertilizer- and Soil-Derived Ammonia Volatilization in a Rice/Wheat Rotation System.

The nitrogen (N) isotope method reveals that application of fertilizer N can increase crop uptake or denitrification and leaching losses of native soil N via the "added N interaction". However, there is currently little evidence of the impact of added N on soil N losses through NH3 volatilization using (15)N methodologies. In the present study, a three-year rice/wheat rotated experiment with 30% (15)N-labeled urea applied in the first rice season and unlabeled urea added in the following five crop seasons was performed to investigate volatilization of NH3 from fertilizer and soil N. We found 9.28% of NH3 loss from (15)N urea and 2.88-7.70% declines in (15)N-NH3 abundance occurred during the first rice season, whereas 0.11% of NH3 loss from (15)N urea and 0.02-0.21% enrichments in (15)N-NH3 abundance happened in the subsequent seasons. The contributions of fertilizer- and soil-derived N to NH3 volatilization from a rice/wheat rotation were 75.8-88.4 and 11.6-24.2%, respectively. These distinct variations in (15)N-NH3 and substantial soil-derived NH3 suggest that added N clearly interacts with the soil source contributing to NH3 volatilization.

Soil Organic Carbon Pool and Its Chemical Composition in Phyllostachy pubescens Forests at Two Altitudes in Jian-ou City, China.

Phyllostachys pubescens forests play an important role in soil organic carbon (SOC) sequestration in terrestrial ecosystems. However, the estimation and mechanism of SOC sequestration by P. pubescens forests remain unclear. In this study, the effect of P. pubescens forest distribution with elevation was investigated at two altitude sites in Jian-ou City, Southeast China. SOC storage was estimated and its chemical composition was obtained via 13C-nuclear magnetic resonance (NMR), chemical classification, and spectral analysis. Results showed that the SOC contents and stocks were significantly higher at the high-altitude site than at the low-altitude site in the entire soil profile (0-60 cm). The C contents of the three combined humus forms exhibited similar responses to the elevation change, and all of these forms were higher at the high-altitude site than at the low-altitude site regardless of soil layer. However, the proportions of the three combined humus C showed no significant differences between the two altitudes. The results of 13C-NMR showed that the SOC chemical composition did not significantly vary with elevation as well. This finding was consistent with the E465/E665 of the loosely combined humus. Overall, the results suggested that altitude should be considered during regional SOC estimation and that altitude affected the quantity rather than the quality of the SOC under the same P. pubescens vegetation.

Mutant GNAQ promotes cell viability and migration of uveal melanoma cells through the activation of Notch signaling.

The occurrence of guanine nucleotide binding protein (G protein), q polypeptide (GNAQ) mutations has been found to be high in the majority of uveal melanomas. However, the underlying molecular mechanism of GNAQ mutations in modulating uveal melanoma is poorly understood. The aim of the present study was to investigate the role and underlying mechanism of mutant GNAQ in the regulation of cell viability and migration of uveal melanoma cells. Uveal melanoma cells containing mutant GNAQ were transfected with scrambled or GNAQ small-interfering RNA. Compared with the control, GNAQ knockdown markedly inhibited cell viability and migration. However, tumor cells without GNAQ mutations exhibited enhanced viability and migration following transfection with HA-GαqQL. Additionally, GNAQ knockdown significantly downregulated the expression of Jag-1 (Notch ligand), Notch intracellular domain and Hes-1 (Notch target gene) in uveal melanoma cells. Conversely, the GNAQ overexpression promoted their expression. Cell viability and migration induced by GNAQ was significantly inhibited following treatment with 5 µmol/l MRK003, a Notch signaling inhibitor. Furthermore, the transfection of human influenza hemagglutinin A epitope (HA)-GαqQL into tumor cells caused Yes-associated protein (YAP) dephosphorylation and nuclear translocation, which stimulated the expression of Jag-1 and Hes-1. Positive correlations were observed between the GNAQ and Jag-1 mRNA levels and between the GNAQ and Hes-1 mRNA levels. However, no positive correlation was observed between the GNAQ and YAP mRNA levels. The results suggested that GNAQ mutation induced viability and migration of uveal melanoma cells via Notch signaling activation, which is mediated by YAP dephosphorylation and nuclear translocation.

Agricultural non-point source pollution in China: causes and mitigation measures.

Non-point source (NPS) pollution has been increasingly serious in China since the 1990s. The increases of agricultural NPS pollution in China is evaluated for the period 2000-2008 by surveying the literature on water and soil pollution from fertilizers and pesticides, and assessing the surplus nitrogen balance within provinces. The main causes for NPS pollution were excessive inputs of nitrogen fertilizer and pesticides, which were partly the result of the inadequate agricultural extension services and the rapid expansion of intensive livestock production with little of waste management. The annual application of synthetic nitrogen fertilizers and pesticides in China increased by 50.7 and 119.7%, respectively, during 1991-2008. The mitigation measures to reduce NPS pollution include: correct distortion in fertilizer prices; improve incentives for the recycling of organic manure; provide farmers with better information on the sound use of agro-chemicals; and tighten the regulations and national standards on organic waste disposal and pesticides use.

[Research on CANON process for municipal sewage in room temperature].

In the room temperature 14.7-24.7 degrees C, simultaneous nitrification-ANAMMOX (CANON) process for municipal sewage was tested by SBR while the DO was controlled between 0.05 and 0.30 mg/L. As a result, the research shows that CANON process can be applied to the nitrogen treatment of municipal wastewater in room temperature by SBR. DO can be regarded as the indication parameter of reaction terminal, and 1 mg/L has been confirmed in the experiment. In the exploring SBR experiments, the consumption velocity of NH4(+) -N was 0.164-0.218 kg/(m3 x d), the production velocity of NO3(-) -N was 0.026-0.036 kg/(m3 x d), the removal velocity and efficiency of TN were 0.124-0.194 kg/(m3 x d) and 65%-75% respectively. Additionally, in the improving SBR experiments, there were three methods for avoiding nitrite accumulation and increasing the nitrogen removal efficiency. They were improving temperature, adding non-aeration period of time and increasing the quantity of ANAMMOX bacteria. Therefore, the removal efficiency of TN was increased to 77%-88% through the three ways above. However, in view of the nitrogen removal velocity and the fact of engineering application condition, the third approach was the best to advance the general ability of ANAMMOX.

[Study of CANON process start-up under aerobic conditions].

The start-up of CANON process was studied to reveal adaptability and how to condense time of start-up with a lab-scale experiment. During start-up stage, temperature was controlled at 35 degrees C +/- 1 degrees C, pH was 7.39-8.01 and free ammonium was 2.89-12.37 mg x L(-1). Partial nitritation was first built up in 60th day and kept steady, nitrite accumulation rate (NO2(-) -N/NO(x) (-) -N) was up to 98%. In the 160th day, the reactor started to show effects of anaerobic ammonium oxidation, and in the 210th day, CANON process was started-up under aerobic conditions successfully, and total nitrogen removal load was 1.22 kg/(m3 x d) and 70% removal rate on average was attained. When using ammonium wastewater without organic carbon sources as influent, there are two signs to indicate the CANON start-up: first, nitrogen gas was produced in carriers; the other one was the ratio of total nitrogen loss and increased nitrate keep steady, and in this study average ratio was 8.61 compared to theoretical value 8.

Reducing environmental risk by improving N management in intensive Chinese agricultural systems.

Excessive N fertilization in intensive agricultural areas of China has resulted in serious environmental problems because of atmospheric, soil, and water enrichment with reactive N of agricultural origin. This study examines grain yields and N loss pathways using a synthetic approach in 2 of the most intensive double-cropping systems in China: waterlogged rice/upland wheat in the Taihu region of east China versus irrigated wheat/rainfed maize on the North China Plain. When compared with knowledge-based optimum N fertilization with 30-60% N savings, we found that current agricultural N practices with 550-600 kg of N per hectare fertilizer annually do not significantly increase crop yields but do lead to about 2 times larger N losses to the environment. The higher N loss rates and lower N retention rates indicate little utilization of residual N by the succeeding crop in rice/wheat systems in comparison with wheat/maize systems. Periodic waterlogging of upland systems caused large N losses by denitrification in the Taihu region. Calcareous soils and concentrated summer rainfall resulted in ammonia volatilization (19% for wheat and 24% for maize) and nitrate leaching being the main N loss pathways in wheat/maize systems. More than 2-fold increases in atmospheric deposition and irrigation water N reflect heavy air and water pollution and these have become important N sources to agricultural ecosystems. A better N balance can be achieved without sacrificing crop yields but significantly reducing environmental risk by adopting optimum N fertilization techniques, controlling the primary N loss pathways, and improving the performance of the agricultural Extension Service.

Impacts of population growth and economic development on the nitrogen cycle in Asia.

Asia is the major consumer of fertilizer nitrogen and energy in the world, and consequently shares a considerable proportion of the world creation of reactive nitrogen (Nr). However, if estimated on per capita basis, Asia is characterized by a lower arable land area, fertilizer nitrogen consumption, energy consumption, and gross domestic product, as well as lower daily protein intake. To meet the increasing needs for food and energy for the growing population combined with the improvement of living standards, Nr will inevitably increase. The present study estimates the creation of Nr and the emissions of various N compounds into environment in Asia currently and in 2030. In comparison with the world averages, the lower fertilizer nitrogen and energy use efficiencies, and the lower use of animal wastes for agriculture imply that there is potential for moderating the increase in Nr and its impacts on the environment. Strategies for moderating the increase are discussed.

Impacts of population growth and economic development on the nitrogen cycle in Asia.

Asia is the major consumer of fertilizer nitrogen and energy in the world, and consequently shares a considerable proportion of the world creation of reactive nitrogen (Nr). However, if estimated on per capita basis, Asia is characterized by a lower arable land area, fertilizer nitrogen consumption, energy consumption, and gross domestic product, as well as lower daily protein intake. To meet the increasing needs for food and energy for the growing population combined with the improvement of living standards, Nr will inevitably increase. The present study estimates the creation of Nr and the emissions of various N compounds into environment in Asia currently and in 2030. In comparison with the world averages, the lower fertilizer nitrogen and energy use efficiencies, and the lower use of animal wastes for agriculture imply that there is potential for moderating the increase in Nr and its impacts on the environment. Strategies for moderating the increase are discussed.

[Ammonia volatilization loss of nitrogen fertilizer from rice field and wet deposition of atmospheric nitrogen in rice growing season].

Plot and field experiments showed that the NH3 volatilization loss from rice field reached its maximum in 1-3 days after N-fertilization, which was affected by the local climate conditions (e.g., sun illumination, temperature, humidity, wind speed, and rainfall), fertilization time, and ammonium concentration in surface water of the rice field. The wet deposition of atmospheric nitrogen was correlated with the application rate of N fertilizer and the rainfall. The amount of nitrogen brought into soil or surface water by the wet deposition in rice growing season reached 7.5 kg.hm-2. The percent of NH4(+)-N in the wet deposition was about 39.8%-73.2%, with an average of 55.5%. There was a significant correlation of total ammonia volatilization loss with the average concentration of NH4(+)-N in wet deposition and total amount of wet deposition in rice growing season.