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Abstract Separation and treatment of human urine from domestic wastewater have been recognized as a sustainable alternative to conventional urban sanitation system, but the unique water quality of source-separated urine, such as high nutrient, insufficient alkalinity and low COD/nitrogen ratio, poses challenges to the biological nitrogen removal process. It was hypothesized that a physicochemical pre-treatment should be adopted to not only reduce nitrogen load but adjust water quality suitable for biological treatment. In this study, a vacuum thermal stripping process coupled to acid absorption was used as a pre-treatment to recover ammonia from hydrolyzed urine in the form of ammonium sulphate. The maximal ammonia mass transfer coefficient of 17.6 mm/h was obtained under 60 °C and 21.3 kPa 80% of the nitrogen in hydrolyzed urine was recovered in 3 h batch stripping experiments without pH adjustment, corresponding to a nitrogen recovery loading rate of 36 kg N/m3⋅d. The majority of organic matters were retained in urine solutions, thus COD/N and alkalinity/NH 4 + N ratios were elevated to 4.75 and 4.37, respectively. Phosphorus recovery could be simultaneously obtained in stripping process by adding MgCl 2. The remaining nitrogen was effectively removed via short-cut nitrification and denitrification in an anoxic/oxic membrane bioreactor. More than 95% of overall nutrient recovery/removal from urine was achieved with a minimal consumption of external resources. The economic assessment of the technique showed that the recovery/removal of nutrients from 1 m3 of urine can make a profit of € 0.26. Graphical abstract Image 1 Highlights • Vacuum thermal stripping (VTS) was used to recover N from source-separated urine. • VTS recovered 80% N and adjusted C/N and alkalinity/N ratios in urine solution. • No external C source was required for biological N removal. • Over 95% P and N recovery/removal was achieved. [ABSTRACT FROM AUTHOR]

Phosphorus (P) recovery from waste streams has recently been recognized as a key step in the sustainable supply of this indispensable and non-renewable resource. The feasibility of using brine from a reverse osmosis (RO) membrane unit treating cooling water as a precipitant for P recovery from source separated urine was evaluated in the present study. P removal efficiency, process parameters and precipitate properties were investigated in batch and continuous flow experiments. More than 90% of P removal was obtained from both undiluted fresh and hydrolyzed urines by mixing with RO brine (1:1, v/v) at a pH over 9.0. Around 2.58 and 1.24 Kg of precipitates could be recovered from 1 m 3 hydrolyzed and fresh urine, respectively, and the precipitated solids contain 8.1–19.0% of P, 10.3–15.2% of Ca, 3.7–5.0% of Mg and 0.1–3.5% of ammonium nitrogen. Satisfactory P removal performance was also achieved in a continuous flow precipitation reactor with a hydraulic retention time of 3–6 h. RO brine could be considered as urinal and toilet flush water despite of a marginally higher precipitation tendency than tap water. This study provides a widely available, low - cost and efficient precipitant for P recovery in urban areas, which will make P recovery from urine more economically attractive. [ABSTRACT FROM AUTHOR]

The combination of partial nitritation (PN) and anaerobic ammonium oxidation (anammox) has been proposed as an ideal process for nitrogen removal from source-separated urine, while the high organic matters in urine cause instability of single-stage PN-anammox process. This study aims to remove the organic matters and partially nitrify the nitrogen in urine, producing an ammonium/nitrite solution suitable for anammox. The organic matters in stored urine were used as the electron donors to achieve 40% total nitrogen removal in nitritation-denitrification process in a sequencing batch reactor (SBR). Granular aggregates were observed and high mixed liquor suspended solids (9.5 g/L) were maintained in the SBR. Around 70-75% ammonium was oxidized to nitrite under the volumetric loading rates of 3.23 kg chemical oxygen demand (COD)/(m d) and 1.86 kg N/(m d), respectively. The SBR produced an ammonium/nitrite solution free of biodegradable organic matters, with a NO -N:NH -N of 1.24 ± 0.13. Fluorescence in situ hybridization images showed that Nitrosomonas-like ammonium-oxidizing bacteria, accounting for 7.2% of total bacteria, located in the outer layer (25 μm), while heterotrophs distributed homogeneously throughout the granular aggregates. High concentrations of free ammonia and nitrous acids in the reactor severely inhibited the growth of nitrite-oxidizing bacteria, resulting in their absence in the granular sludge. The microbial diversity analysis indicated Proteobacteria was the predominant phylum, in which Pseudomonas was the most abundant genus. [ABSTRACT FROM AUTHOR]

In this study, a novel self-sustainable solar assisted photoelectro-Fenton (SPEF) system driven by a solar photovoltaic cell was developed for the efficient mineralization of antibiotic trimethoprim (TMP) in water. A comparative degradation of 200 mg L −1 TMP by RuO 2 /Ti anodic oxidation (AO), anodic oxidation with H 2 O 2 electrogeneration (AO-H 2 O 2 ), electro-Fenton (EF) and SPEF was investigated. SPEF was proved to exhibit the highest oxidation power, i.e., more than 80% TOC was removed after 360 min SPEF treatment of 200 mg L −1 of TMP under optimal conditions at pH 3.0, 1.0 mM Fe 2+ and 18 mA cm −2 . Influences of current density, pH, initial Fe 2+ and initial TMP concentration on SPEF process were also studied. Ten aromatic intermediates generated from hydroxylation, carbonylation and demethylation reactions were identified using UPLC-QTOF-MS/MS system during the SPEF treatment, together with three carboxylic acids (oxamic, oxalic and formic acids) and two inorganic ions (NH 4 + and NO 3 − ) measured. Therefore, a reasonable pathway of TMP degradation in SPEF process was proposed. [ABSTRACT FROM AUTHOR]

Abstract: High photocatalytic activity La2Ti2O7 was synthesized by a novel mineralization polymerizable complex (MPC) method. Compared with La2Ti2O7 prepared by polymerizable complex (PC) method, MPC-La2Ti2O7 showed larger surface areas, higher crystallization and more uniform morphology. These factors resulted in a dramatic improvement of its photocatalytic activity for hydrogen evolution. The photocatalytic activity of MPC-La2Ti2O7 was about three times higher than that of PC-La2Ti2O7. [Copyright &y& Elsevier]

Phosphorus (P) recovery from wastewater has been recognized as a critical technology for solving the sustainable supply of this indispensable and non - renewable natural resource. In this study, the cost - free magnesium and calcium sources of using the cooling water system effluent (CWSE) in two thermal power plants were proposed (Z - CWSE and G - CWSE) and the P recovery performance from source - separated urine was investigated. About 90% P recovery efficiency was achieved from the hydrolyzed urine when Z - CWSE and G - CWSE were added at the Ca: Mg: P molar ratios of 3.1 : 4.0: 1 and 3.6 : 3.4: 1, respectively. More than 95% P recovery performance was obtained from the fresh urine as the initial pH of the CWSE - FU mixtures was adjusted to over 9.5 and 10.0, respectively. The precipitates obtained contain 10.84–17.04% Ca, 6.22–9.58% P, 0.75–3.76% Mg and 0.13–0.23% N. XRD analysis confirmed the presence of struvite in the precipitates. The reuse of precipitates is secure due to extremely low contents of heavy metals. The feasibility of using CWSEs as the flushing water in urinals and toilets was assessed. Besides, we proposed CWSEs could be invoked as precipitants in various wastewaters as long as it contains considerable phosphate, e.g. P concentration more than 100 mg/L and 50 mg/L for Z - CWSE and G - CWSE, respectively. • CWSEs are effective magnesium and calcium sources for P recovery from urine. • 90–95% P was recovered from urine at the CWSEs/urine of 2.5:1 (v/v) at pH > 9.0. • Precipitates contain 6.22–9.58% P and no harmful heavy metals are detected. • CWSEs can be potentially used as urinal and toilet flushing water. • CWSEs can be used to recover P from wastewaters contained >50 mg P/L. [ABSTRACT FROM AUTHOR]

• Comparative degradation of cefoperazone by PEF with RuO 2 /Ti or BDD anode; • Faster decay and higher mineralization achieved by PEF with BDD anode; • Generated BDD(•OH) contributed to superior powers of PEF with BDD anode; • Quantification of H 2 O 2 and •OH illustrated the oxidation characteristic. The mineralization of 125 mL of 50–300 mg L−1 cefoperazone (CFPZ) has been comparatively studied by electrochemical advanced oxidation processes (EAOPs) like anodic oxidation (AO), electro-Fenton (EF) and photoelectro-Fenton (PEF) with a RuO 2 /Ti or boron-doped diamond (BDD) anode and an activated carbon fiber (ACF) cathode. A microwave discharge electrodeless lamp (MDEL) was used as the UV source in PEF process. CFPZ decays always followed pseudo-first-order kinetics and their constant rates increased in the order: AO < EF < MDEL-PEF, regardless of anode types. Higher mineralization was achieved in all methods using BDD instead of RuO 2 /Ti, while the most potent BDD-MDEL-PEF gave 88% mineralization under its optimum conditions of 0.36 A, pH 3.0 and 1.0 mmol L−1 Fe2+. The synergistic mechanisms were explored by quantifying the electrogenerated H 2 O 2 and formed •OH, in which 2.27 and 2.58 mmol L-1 H 2 O 2 were accumulated in AO-H 2 O 2 with RuO 2 /Ti or BDD anode, respectively, while 92.0 and 263.5 μmol L-1 •OH were generated in EF with RuO 2 /Ti or BDD anode, respectively. The oxidation power of EAOPs with different anodes was also compared by measuring the evolutions of NO 3 − and NH 4 + as well as four generated carboxylic acids including oxalic, oxamic, formic and fumaric acids. [ABSTRACT FROM AUTHOR]

Abstract Solutions of 200 mg L−1 cefalexin (CLX), an antibiotic with high usage frequency and biodegradation resistance, have been comparatively degraded by electro-Fenton (EF) and photoelectro-Fenton (PEF) processes using two kinds of activated carbon fiber (ACF) cathodes with different physical properties. These two ACFs shared similar pore volumes and pore diameters but varied BET surface areas, which were confirmed to be 0.5210 cm3 g−1, 2.26 nm and 921 m2 g−1 for ACF1, while 0.6508 cm3 g−1, 2.16 nm and 1206 m2 g−1 for ACF2, respectively. Their oxidation abilities were comparatively assessed in terms of degradation kinetics and mineralization rates, which increased in the order: ACF1-EF < ACF2-EF < ACF1-PEF < ACF2-PEF. These results confirmed the superiority of ACF with higher surface area, which was correlated to faster H 2 O 2 and OH accumulation in more reaction sites provided. After 120 min electrolysis, ACF1 exhibited 1510 μM H 2 O 2 and 37 μM OH accumulation, while ACF2 generated 1934 μM H 2 O 2 and 85 μM OH. Moreover, ACF cathode with more developed pore structure also revealed faster formation of degradation by-products like inorganic ions (NH 4 + and NO 3 − ions) and short-chain carboxylic acids (acetic, formic, oxamic and oxalic acids), as well as enhanced removal for partial acids. In order to gain a deeper understanding of degradation mechanisms for ACF2-PEF system, evolutions of six aromatic by-products generated from sulfoxidation, hydroxylation and decarboxylation were confirmed by UPLC-QTOF-MS/MS determination. Based on the above identifications of the degradation intermediates, a plausible reaction pathway for CLX removal was proposed. Graphical abstract Image 1 Highlights • Cefalexin was degraded by EAOPs with varied surface properties ACF cathodes. • Faster decay and higher mineralization achieved by larger specific area cathode. • ACF with higher specific area could promote H 2 O 2 and OH production. • Quicker by-products formation and elimination attained in more porous ACF cathode. • 6 aromatic products were detected and a plausible reaction pathway was proposed. [ABSTRACT FROM AUTHOR]

Owing to the high contents of organics and nitrogen in vacuum toilet wastewater (VTW) generated from high-speed trains, onsite pretreatment is usually required before VTW can be discharged into municipal sewers. In this study, a partial nitritation process was stably established in a sequential batch reactor to efficiently utilize the organics in synthetic and real VTWs for nitrogen removal and to produce an effluent suitable for anaerobic ammonia oxidation. In spite of the high fluctuations of COD and nitrogen in VTW, the organics used for nitrogen removal stabilized at 1.97 ± 0.18 mg COD mg N−1 removed, and the effluent NO 2 −-N/NH 4 +-N ratios were maintained at 1.26 ± 0.13. The removal efficiencies of nitrogen and COD were 31.8 ± 3.5% and 65.2 ± 5.3% under the volumetric loading rates of 1.14 ± 0.15 kg N m−3 d−1 and 1.03 ± 0.26 kg COD m−3 d−1 for real VTW, respectively. Microbial community analysis revealed that Nitrosomonas (0.95%–1.71%) was the dominant autotrophic ammonium-oxidizing bacterial genus, but nitrite-oxidizing bacteria, Nitrolancea , was severely inhibited, with a relative abundance less than 0.05%. The relative abundance of denitrifying bacteria increased by 7.34% when the influent was switched to real VTW. Functional profile predictions of the biomass showed that the decrease in the COD/N ratio and the switch of reactor influent from synthetic to real VTW increased the relative abundance of enzymes and modules involved in carbon and nitrogen metabolisms. [Display omitted] • Stabilized Partial nitritation and nitrogen removal were achieved for VTW. • The organics used for nitrogen removal stabilized at 1.97 ± 0.18 mg COD mg N−1. • Stepwise fed SBR system achieved 31.2% nitrogen removal for real VTW. • Stable effluent NO 2 −–N/NH 4 +–N ratio of 1.26 was achieved for real VTW. • Higher abundance of denitrifying bacteria was observed in real than synthetic VTWs. [ABSTRACT FROM AUTHOR]

In this study, a novel photoelectro-Fenton (PEF) process using microwave discharge electrodeless lamp (MDEL) as a UV irradiation source was developed for the removal of antibiotic ciprofloxacin (CIP) in water. Comparative degradation of 200 mg L −1 CIP was studied by direct MDEL photolysis, anodic oxidation (AO), AO in presence of electrogenerated H 2 O 2 (AO-H 2 O 2 ), AO-H 2 O 2 under MDEL irradiation (MDEL-AO-H 2 O 2 ), electro-Fenton (EF) and MDEL-PEF processes. Higher oxidation power was found in the sequence: MDEL photolysis < AO < AO-H 2 O 2 < MDEL-AO-H 2 O 2 < EF < MDEL-PEF. Effects of current density, pH, initial Fe 2+ concentration and initial CIP concentration on TOC removal in MDEL-PEF process were examined, and the optimal conditions were ascertained. The releases of three inorganic ions (F − , NH 4 + and NO 3 − ) and two carboxylic acids (oxalic and formic acids) were qualified. Seven aromatic intermediates mainly generated from hydroxylation, dealkylation and defluorination of CIP were detected by UPLC-QTOF-MS/MS technology. Therefore, plausible degradation sequences for CIP degradation in MDEL-PEF process including all detected products were proposed. [ABSTRACT FROM AUTHOR]

This work investigated the effect of the chelation of Fe 3+ with a fluoroquinolone (FQ) antibiotic ciprofloxacin (CIP) on the catalytic behavior of Fe 3+ /Fe 2+ and the degradation and mineralization of CIP in electro-Fenton (EF) process using activated carbon fiber (ACF) felt cathode. First of all, effect of initial Fe 2+ and Fe 3+ concentrations on the degradation and mineralization of CIP in EF process was compared, while the optimal initial Fe 2+ and Fe 3+ contents were both verified to be 1.50 mmol dm −3 , in which 73% and 72% of initial TOC were eliminated after 360 min electrolysis, respectively. Secondly, Fe 3+ -CIP chelate was produced during CIP degradation in EF process, whose predominant form was confirmed as 1:2 metal-ligand stoichiometry. The formation of Fe 3+ -CIP chelate had no obvious inhibition on the degradation and mineralization of CIP due to the efficient Fe 3+ reduction on the ACF cathode with excellent catalytic feature. About 17% and 35% of initial 1.50 mmol dm −3 Fe 3+ were reduced to Fe 2+ at 18 mA cm −2 in ultrapure water and 200 mg dm −3 CIP solutions during 30 min pre-aeration of EF process, respectively, while higher Fe 2+ concentration was maintained for initial 1.50 mmol dm −3 Fe 3+ during CIP degradation. Finally, the evolution of F − , NH 4 + and NO 3 − ions released to the acidic medium were determined, as well as the formation of short-chain carboxylic acid (oxalic, oxamic and formic acids). Eight aromatic intermediates were identified using UPLC-QTOF-MS/MS, and a feasible mineralization pathway was proposed. [ABSTRACT FROM AUTHOR]

Source separation and treatment of human urine have been recognized as a resource-efficient alternative to conventional urban drainage, not only reducing nutrient loads on municipal wastewater treatment plants, but recovering valuable resources from waste streams. In this work, on-site phosphorus (P) recovery from real urine was carried out by using the brine from a reverse osmosis process as the flush water for urine-diverting toilets and a P precipitant, while nitrogen (N) was removed via short-cut nitrification-denitrification (SCND) in a membrane bioreactor (MBR). More than 90% of P was recovered by mixing the urine with reverse osmosis brine (1:1, v/v) under the condition of pH > 9.0. The recovered precipitates contained 10–15% of P and can potentially be reused for phosphate fertilizer production. Stable SCND was achieved in a MBR, and 45% of N was removed with the organic compounds in urine as the electron donor for denitrification. Methanol addition significantly elevated denitrification, which in turn replenished the alkalinity required for nitrification. More than 99% of P, 90% of organics and 90% of N were removed in the combined precipitation and MBR process. Nitrosomonas was observed to be the predominant ammonium-oxidizing bacteria, while nitrite-oxidizing bacteria (NOB) were absent in the microbial communities as revealed by fluorescence in situ hybridization and pyrosequencing technique. High concentrations of free ammonia and nitrite acids, as well as low dissolved oxygen, are the prevailing factors to inhibit the growth of NOB, which allows for stable operation of SCND in the MBR. [ABSTRACT FROM AUTHOR]

Solutions of 500 mL 200 mg L −1 fluoroquinolone antibiotic levofloxacin (LEVO) have been degraded by anodic oxidation (AO), AO with electrogenerated H 2 O 2 (AO–H 2 O 2 ) and electro-Fenton (EF) processes using an activated carbon fiber (ACF) felt cathode from the point view of not only LEVO disappearance and mineralization, but also biodegradability enhancement. The LEVO decay by EF process followed a pseudo-first-order reaction with an apparent rate constant of 2.37 × 10 −2 min −1 , which is much higher than that of AO or AO–H 2 O 2 processes. The LEVO mineralization also evidences the order EF > AO–H 2 O 2 > AO. The biodegradability (BOD 5 /COD) increased from 0 initially to 0.24, 0.09, and 0.03 for EF, AO–H 2 O 2 and AO processes after 360 min treatment, respectively. Effects of several parameters such as current density, initial pH and Fe 2+ concentration on the EF degradation have also been examined. Three carboxylic acids including oxalic, formic and acetic acid were detected, as well as the released inorganic ions NH 4 + , NO 3 − and F − . At last, an ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry was used to identify about eight aromatic intermediates formed in 60 min of EF treatment, and a plausible mineralization pathway for LEVO by EF treatment was proposed. [ABSTRACT FROM AUTHOR]

Removal of the refractory organic matters in leachate brines generated from nanofiltration unit in two full-scale municipal solid waste landfill leachate treatment plants was investigated by Fenton oxidative-coagulation and ultraviolet photo – Fenton processes in this study. Fenton oxidative-coagulation was performed under the condition of an initial pH of 5.0 and low H 2 O 2 /Fe 2+ ratios. After precipitate separation, the remaining organic constituents were further oxidized by photo – Fenton process. For both leachate brines with varying pollution strength, more than 90% COD and TOC reductions were achieved at H 2 O 2 /Fe 2+ dosages of 35 mM/8 mM and 90 mM/10 mM, respectively. The effluent COD ranged 120–160 mg/L under the optimal operating conditions, and the biodegradability was increased significantly. Fenton oxidative-coagulation was demonstrated to contribute nearly 70% overall removal of organic matters. In the combined processes, the efficiency of hydrogen peroxide varied from 216 to 228%, which may significantly reduce the operating cost of conventional Fenton method. Six phthalic acid esters and thirteen polycyclic aromatic hydrocarbons were found in leachate brines, and, on the average, around 80% phthalic acid esters and 90% polycyclic aromatic hydrocarbons were removed by the combined treatments. [ABSTRACT FROM AUTHOR]

Biologically treated leachate usually contains considerable amount of refractory organics and trace concentrations of xenobiotic pollutants. Removal of refractory organics from biologically treated landfill leachate by a novel microwave discharge electrodeless lamp (MDEL) assisted Fenton process was investigated in the present study in comparison to conventional Fenton and ultraviolet Fenton processes. Conventional Fenton and ultraviolet Fenton processes could substantially remove up to 70% of the refractory organics in a membrane bioreactor treated leachate. MDEL assisted Fenton process achieved excellent removal performance of the refractory components, and the effluent chemical oxygen demand concentration was lower than 100 mg L−1. Most organic matters were transformed into smaller compounds with molecular weights less than 1000 Da. Ten different polycyclic aromatic hydrocarbons were detected in the biologically treated leachate, most of which were effectively removed by MDEL-Fenton treatment. MDEL-Fenton process provides powerful capability in degradation of refractory and xenobiotic organic pollutants in landfill leachate and could be adopted as a single-stage polishing process for biologically treated landfill leachate to meet the stringent discharge limit. [ABSTRACT FROM AUTHOR]

Cystic echinococcosis (CE) is a global parasitic zoonosis caused by Echinococcus granulosus . The disease is highly endemic in western China, especially in Tibetan areas, because of poor economic development and hygiene conditions, limited community knowledge of CE, a large scale of dogs, and home slaughtering of livestock. Although many researchers have analyzed risk factors of CE transmission in Tibetan Plateau, there are rare reports of knowledge, attitude, and practice (KAP) of residents about CE in Tibetan communities. In our current study, community based cross-sectional study was conducted in three townships in Xiahe County, Gannan Tibetan Autonomous Prefectures of Gansu Province from May to September 2013. A total of 972 participants originating from Tibetan communities of 31 villages in the 3 townships were registered and data were collected using structured questionnaires. From the total of 972 study participants (457 males and 515 females), 65.9% heard of the disease CE. Most of them (96.1%) would like to accept CE inspection. About half of the peoples feed their dogs often and major of them do not play with the dogs. Risk factors included resident, knowing dog could be infected, knowing eating could be route of infection, oldest dog's age, usually feed your dog by self, feed dogs with internal organs. In general our findings showed that most of residents had positive attitude toward treatments of the disease, but their practice about disease prevention and control was low. Therefore, our study called for continued and strengthened education of changing the life style, especially the behaviors related to dogs. [ABSTRACT FROM AUTHOR]

Oxidation of a commonly-used β-lactam pharmaceutical, cefoperazone (CFPZ), was systematically investigated by anodic oxidation (AO), AO in presence of H 2 O 2 electro-generation (AO-H 2 O 2) and electro-Fenton (EF) processes with an activated carbon fiber cathode from the biodegradability viewpoint. The degradation and mineralization rates increased in a sequence of AO < AO-H 2 O 2 < EF. Even CPFZ could be efficiently degraded in EF process, achieving complete CFPZ mineralization was rather difficult. Thereby, the biodegradability of the effluent after electrochemical pretreatment was examined to test the feasibility of the combination of electrochemical and biological processes. The results suggested that compared with AO and AO-H 2 O 2 , EF process could effectively transform the non-biodegradable CFPZ into biocompatible materials with a high BOD 5 /COD value (0.33 after 720 min), allowing the possible biotreatment for further remediation. This behavior was relatively accorded with the average oxidation state (AOS) results, evidencing the potential of EF process in enhancing the biodegradability of CFPZ. The determination of inorganic ions revealed that N in CFPZ molecular was oxidized into NH 4 + and NO 3 − ions in EF process. Oxalic, succinic, oxamic, fumaric and formic acids were also formed. Besides, six aromatic by-products were qualified and a possible pathway involving hydrolysis, hydroxylation and decarboxylation during CFPZ mineralization was proposed. Image 1 • CFPZ underwent complete degradation but partial mineralization in EF condition. • Obvious biodegradability improvement was obtained during EF process. • The feasibility of combing EF with biological treatment was demonstrated. • Aromatic intermediates, carboxylic acids and inorganic ions were determined. • A comprehensive CFPZ degradation pathway involving.•OH was proposed. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFASs) have been detected in many agricultural products in contaminated fields and in supply chains. Roots are the main organ in plants to uptake and bio-accumulate PFASs, but the changes of metabolic regulation in roots by PFASs are largely unexplored. Here, lettuce exposed to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) at different concentrations (500, 1000, 2000 and 5000 ng/L) was investigated via metabolomics. Many key metabolites, such as antioxidants, lipids, amino acids, fatty acids, carbohydrates, linolenic acid derivatives, purine and nucleosides, were significantly altered. Tyrosine metabolism, purine metabolism, isoquinoline alkaloid biosynthesis and terpenoid backbone biosynthesis were altered in roots by PFOA and PFOS. Tricarboxylic acid cycle was perturbed by 5000 ng/L exposure. Activation of antioxidant defense pathways, reallocation of carbon and nitrogen metabolism, regulation of energy metabolism and purine metabolism were reprogrammed in roots. Lettuce employed multiple strategies to increase tolerance to PFOA and PFOS, which includes the adjustment of membrane composition, elevation of inorganic nitrogen fixation and respiration, accumulation of sucrose and regulation of signaling molecules. The results of this study offer insights into the molecular reprogramming of plant roots in response to PFAS exposure and provide important information for the risk assessment of PFASs in environment. Unlabelled Image • Metabolomic profiling revealed toxicity of PFOA and PFOS to lettuce roots. • Tyrosine, purine, isoquinoline alkaloids and terpenoids metabolisms were altered. • Lettuce root response included the reprogramming of metabolic pathways. • Multiple metabolic regulations in roots were activated to cope with PFAS stress. • C/N metabolism and signal transduction were regulated in roots by PFOA and PFOS. [ABSTRACT FROM AUTHOR]

• Phytotoxicity induced by PFOA or PFOS was investigated via metabolomics. • PFOA and PFOS affect the overall metabolic profiles in lettuce leaves. • Pathways in energy metabolism were perturbed by both PFOA and PFOS. • Defense mechanisms in lettuce leaves under exposure to PFOA or PFOS were proposed. Poly- and perfluoroalkyl substances (PFASs) are becoming common pollutants in natural environment, while the toxic effects and defense mechanisms in agricultural plants are poorly understood. Here, lettuce exposed to either perfluorooctanoic acid (PFOA) or perfluorooctane sulfonate (PFOS) at two different concentrations (500, 5000 ng/L) in hydroponic media was investigated via metabolomics. Under the tested conditions, the growth and biomass of lettuce were not affected by PFOA and PFOS, but metabolic profiles in leaves were altered. The composition and metabolism of lipids, carbohydrates, fatty acids, amino acids and some antioxidants were regulated, compromising the nutritional quality of the plants. Key pathways in energy metabolism were disturbed by both PFOA and PFOS, including tricarboxylic acid cycle, glyoxylate and dicarboxylate metabolism and pyruvate metabolism. Amino acid metabolism, e.g., phenylalanine and tyrosine, was disturbed by PFOA. The metabolism of linoleic acid was disturbed by PFOS. The changes of antioxidants and 8-hydroxy-deoxyguanosine indicated the occurrence of oxidative stress and DNA damage under PFOA or PFOS exposure. The main defense processes against PFASs exposure in lettuce included alteration in plasma membrane, activation of antioxidant systems, increase of tolerance and repair of DNA injury. These findings help elucidate the response of plants to PFASs in a molecular-scale perspective. [ABSTRACT FROM AUTHOR]

Background: The point mutations in 23S rRNA gene of Mycoplasma pneumoniae (M. pneumoniae) can lead to high-level resistance to macrolides. This study aimed to evaluate allele-specific real-time PCR (ASPCR) to detect the resistance-related mutations located at positions A2063G and A2064G of 23S rRNA gene.Methods: We detected 178 pharyngeal swab specimens and calculated the proportions of resistant and sensitive quasispecies using ASPCR assays. ASPCR assays can detect down to 10 copies of 23S rRNA gene and achieved sensitivities of < 0.1% for A2063G and A2064G. We also compared the findings of ASPCR with the results of nested PCR with sequencing.Results: Of 178 samples, 164 were found to have M. pneumoniae including 90.85% (149/164) samples with macrolide-resistant M. pneumoniae (MRMP) quasispecies by ASPCR, while 153 were found to be M. pneumoniae-positive including 71.90% (110/153) samples with MRMP quasispecies by nested PCR with sequencing. Of the 164 M. pneumoniae-positive samples, 61.59% (101/164) had the mixed population of wild-type and mutant M. pneumoniae, and 56.44% (57/101) of the latter contained the mutations at low frequency (≤50%).Conclusion: ASPCR indicated that sensitive and resistant quasispecies coexisted in most of the M. pneumoniae positive samples. The ASPCR was a highly sensitive, accurate and rapid method for detecting the macrolide resistance-associated mutations and it could provide earlier and more drug-resistant information for M. pneumoniae research and the clinical therapy. [ABSTRACT FROM AUTHOR]