Prokaryotic expression of soluble IFN-λ1 recombinant protein with cold-shock system.

Interferon (IFN)-λ1, a member of type III IFN, possesses unique antiviral, anti-tumor, and immune modulation properties. IFN-λ alone or combined with other drugs is considered an essential therapeutic regimen in the clinic. Obtaining high-quality, biologically-active recombinant human IFN-λ1 (rhIFN-λ1) is of great practical significance. In this study, pCold-II-IFN-λ1 expression plasmid was correctly constructed, the rhIFN-λ1 was expressed in BL21(DE3) E.coli and reached the highest level under the optimal condition of 15 °C culture temperature and at 1 µg/L IPTG induction for 12 h. The soluble rhIFN-λ1 was purified by Ni-NTA affinity chromatography. The purified rhIFN-λ1 can effectively activate the JAK1-STAT1 signaling pathway and induce the expression of a large number of interferon-stimulated genes (ISG) including ISG15, ISG54, ISG56, TRAIL, OAS1, MX1, IRF7 and IRF9. In addition, rhIFN-λ1 can effectively inhibit the growth/proliferation of cervical cancer HeLa cells in a dose-dependent pattern. Collectively, the soluble rhIFN-λ1 was successfully expressed in BL21(DE3) E.coli with the cold-shock system, and the purified rhIFN-λ1 demonstrated excellent biological activity. This study lays a solid basis for acquiring high-quality rhIFN-λ1 and its clinical application.

Enhanced remediation of heavy metals contaminated soils with EK-PRB using ß-CD/hydrothermal biochar by waste cotton as reactive barrier.

Heavy metals in the soil are major global environmental problems. Waste cotton was used to synthesize a novel ß-CD/hydrothermal biochar (KCB), which is a low-cost and environment-friendly adsorbent for heavy metal soil remediation. KCB were used as reactive materials of electrokinetic-permeable reactive barrier (EK-PRB) to explore the removal characteristics of heavy metals. FTIR and XPS analysis revealed that KCB contained large numbers of surface functional groups. Adsorption of KCB for Pb2+ and Cd2+ reached 50.44 mg g-1 and 33.77 mg g-1, respectively. Metal ions in contaminated soil were removed by reactive barrier through electromigration, electrodialysis and electrophoresis, the removal efficiency of Pb2+ and Cd2+ in soil reached 92.87% and 86.19%. This finding proves that KCB/EK-PRB can be used as a cheap and green process to effectively remediate soils contaminated with heavy metals.

Enhanced bioelectricity output of microbial fuel cells via electrospinning zeolitic imidazolate framework-67/polyacrylonitrile carbon nanofiber cathode.

In this study, the zeolitic imidazolate framework-67 (ZIF-67) and electrospinning polyacrylonitrile membrane were combined to prepare electrospinning carbon nanofibers composite cathode (ZIF-67/CNFs) which could enhance the oxygen reduction reaction (ORR) performance of microbial fuel cells (MFCs) cathode. The optimum electrode 3 wt% ZIF-67/CNFs revealed the excellent ORR performance with a half-wave potential of -0.03 V vs. Ag/AgCl, which was more positive than Pt/C-CC (-0.09 V vs. Ag/AgCl). The highest output voltage (607±9 mV) and maximum power density (1.191±0.017 W m-2) were obtained when the prepared ZIF-67/CNFs electrode was applied to the cathode of MFC (ZIF-67/CNFs-MFC). In addition, ZIF-67/CNFs-MFC showed the best pollutant removal effect. Geobacter was the highest proportion of microbial in ZIF-67/CNFs-MFC. The results have shown that the application of ZIF-67/CNFs electrode to MFC cathode is promising.

Synergistic impacts of Cu2+ on simultaneous removal of tetracycline and tetracycline resistance genes by PSF/TPU/UiO forward osmosis membrane.

Cu2+, tetracycline (TC), and corresponding tetracycline resistance genes (TRGs) are common micropollutants in aquaculture wastewater, which have great impact on environment and human health. In this study, we developed a thin-film nanocomposite (TFN) forward osmosis (FO) membrane with an electrospinning thermoplastic polyurethane/polysulfone (PSF/TPU) substrate and a UiO-66-NH2 particle interlayer modified active layer. The effects of Cu2+ concentration on the synergetic removal of TC and TRGs (e.g., tetA/M/X/O/C, int1, and 16 S rRNA gene) were analyzed to determine the role of Cu2+ in FO process. The rejection mechanism was also analyzed in depth. Results demonstrated that the rejection of TC and Cu2+ was 99.53% and 97.99%. The rejection of TRGs exceeded 90% (specifically, over 99% for tetC) at a Cu2+ concentration of 500 µg/L when 0.5 M (NH4)2HPO4 was used as draw solution. Complexation reaction between Cu2+ and TC, electrostatic interaction, and the adsorption of Cu2+ on membrane surface were the main contributing factors for the high rejection efficiencies. Altogether, the as-prepared FO membrane holds great potential for simultaneously removing heavy metals, antibiotics, and resistance genes in real wastewater.

Denitrification performance evaluation and kinetics analysis with mariculture solid wastes (MSW) derived carbon source in marine recirculating aquaculture systems (RAS).

Biological denitrification using mariculture solid wastes (MSW) carbon source is a promising solution for removing nitrate (NO3--N) and disposing MSW in marine recirculating aquaculture systems (RAS). To enhance denitrification performance, heating (HT), rhamnolipid (RL), alkali (AL), thermophilic bacteria (TB) pre-treated MSW acidogenic fermentation effluents were prepared as carbon sources. Profiles of soluble organics in four types of fermentation effluents were first evaluated. The highest volatile fatty acids (VFAs) yield (52.1%) was obtained from TB treated MSW after acidification. RL and TB treated MSW acidogenic fermentation effluents showed high NO3--N removal efficiency (NRE) (around 97%). Acidogenic fermentation effluent from TB treated MSW presented a high biodegradability, with the minimum effluent chemical oxygen demand (COD) amount (35 mg/L). Denitrification kinetics parameters were also analyzed; high fraction (74.5%) of the most readily biodegradable organics (SS) demonstrated that TB treated MSW acidogenic fermentation effluent is a high-quality carbon source for enhancing denitrification.

Heterotrophic denitrification strategy for marine recirculating aquaculture wastewater treatment using mariculture solid wastes fermentation liquid as carbon source: Optimization of COD/NO3--N ratio and hydraulic retention time.

Heterotrophic denitrification using mariculture solid wastes (MSW) fermentation liquid as carbon source is an economically and environmentally sustainable strategy for NO3--N removal in marine recycling aquaculture systems (RAS). The optimization of COD/NO3--N ratio (C/N) and hydraulic retention times (HRT) with respect to MSW fermentation liquid driven denitrification for marine RAS wastewater treatment was investigated. The optimum C/N of 8 and HRT of 6 h for heterotrophic denitrification was obtained with NO3--N removal efficiency of 97.8% and 94.2%, respectively. Using MSW fermentation liquid as carbon source, the utilization of VFAs was more effective than that of carbohydrates and proteins, and effluent COD concentration decreased with an increment in HRT from 4 to 8 h. The results of high-throughput sequencing analysis showed microbial communities were enriched selectively in the reactors by optimizing C/N and HRT, which obviously enhanced the nitrogen removal in respect to MSW fermentation liquid driven denitrification.

[Performance and Membrane Fouling Properties in an Anaerobic Membrane Bioreactor for Salty Wastewater].

In the research, an anaerobic membrane bioreactor (AnMBR) was used to treat simulated salty organic wastewater, and the effect of salinity on reactor performance and membrane fouling properties was investigated. The results indicated that when the influent salinity increased gradually but was lower than 9.1 g·L-1, the reactor ran stably and the effluent performance was good. When the salinity increased to 10 g·L-1, the COD removal-efficiency, gas production, and methane content decreased significantly; meanwhile, the sludge concentration, sludge volume index (SVI), soluble microbial products (SMP), and extracellular polymeric substance (EPS) levels became elevated at first and then declined with the rising salinity. The system developed compact flocs and a high settling ability. The hollow fiber membrane module was run for three cycles in 118 d. The membrane operating cycle was extended from 31 d to 48 d with the increasing salinity, which favored the control of membrane fouling. SEM-EDX analysis results revealed that there were similar crystalline substances in the film membrane foulants, and Na, Mg, Al, Si, Cl, K, Ca, and Fe were the main inorganic elements. Excitation emission matrix (EEM) analysis results demonstrated that proteins and humic acids were the main components of the organic membrane foulants.

Enhancing denitrification efficiency for nitrogen removal using waste sludge alkaline fermentation liquid as external carbon source.

External carbon source was usually added to enhance denitrification efficiency for nitrogen removal in wastewater treatment. In this study, waster sludge alkaline fermentation liquid was successfully employed as an alternative carbon source for biological denitrification. The denitrification performance was studied at different C/Ns (carbon-to-nitrogen ratios) and HRTs (hydraulic retention times). A C/N of 7 and an HRT of 8 h were the optimal conditions for denitrification. The nitrate removal efficiency of 96.4% and no obvious nitrite accumulation in the effluent were achieved under the optimal conditions with a low soluble chemical oxygen demand (SCOD) level. The sludge carbon source utilization was analyzed and showed that the volatile fatty acids (VFAs) were prior utilized than proteins and carbohydrates. The excitation-emission matrix (EEM) spectroscopy with fluorescence regional integration (FRI) was adopted to analyze the compositional and variations of dissolved organic matters (DOM). Moreover, a high denitrification rate (VDN) and potential (PDN) with low heterotroph anoxic yield (YH) was exhibited at the optimal C/N and HRT condition, indicating the better denitrification ability and organic matter utilization efficiencies.

The influence of Fe2+, Fe3+ and magnet powder (Fe3O4) on aerobic granulation and their mechanisms.

This study aimed to develop an aerobic granular sludge and understand the granulation process of the multi-iron ions. Four sequencing batch reactors (SBRs) were applied to elucidate the effect of Fe2+, Fe3+ and Fe3O4 addition on aerobic granulation. The results confirmed that the start-up time of aerobic granulation with Fe3O4 addition (11 days) was notably less than that with Fe2+ (16 days) and Fe3+ (27 days) addition. Larger granules achieved with Fe3O4 addition with a sludge volume index (SVI30) of 28.50 mL/g and settling velocity of 49.68 m/h. Scanning electron microscope (SEM) analysis further revealed that the presence of mineral crystal in the granule core with Fe2+ and Fe3O4 addition accelerated the granule formation and maintained the stability of the structure. Extracellular polymeric substances (EPS) were studied using three-dimensional-excitation emission matrix (3D-EEM) fluorescence spectra technology to gain a comprehensive view of the interactions between EPS and Fe2+, Fe3+ and Fe3O4. Around 94.76% and 97.68% removal rate was noted for COD and ammonia in the granulation process. Finally, the dominant functional species involved in biological nutrients removal and granule formation were identified by high throughput sequencing technology to assess the effects of Fe2+, Fe3+ and Fe3O4 to granule at the molecular level.

Characterization of two pigeon paramyxovirus type 1 isolates in China.

For over three decades, there has been a continuing panzootic caused by a virulent variant avian paramyxovirus type 1 strain, the so-called pigeon paramyxovirus type 1. It is found primarily in racing pigeons, but it has also spread to wild birds and poultry. In this study, two pigeon paramyxovirus type 1 strains, SD12 and BJ13, obtained from diseased pigeons in China, were characterized. Phylogenetic analysis based on complete sequences allowed characterization of both strains as genotype VI, class II. Further phylogenetic analysis of a 374-nucleotide section of the fusion gene showed that SD12 fell into lineage VIbii-d and BJ13 into VIbii-f. The deduced amino acid sequence of the cleavage site of the fusion protein confirmed that both isolates contained the virulent motif (112)K/RRQKR↓F(117) at the cleavage site. Nevertheless, the values of intracerebral pathogenicity indices showed the SD12 isolate to be a velogenic strain and BJ13 isolate to be a mesogenic strain. The SD12 isolate was further investigated via clinical observation, RNA detection, histopathology and viral serology in experimentally infected 3-week-old chickens. It showed a mild pathological phenotype in chickens, with viral replication restricted to a few tissues. The molecular mechanism for the SD12 isolate to have a virulent motif but low levels of virulence for chickens requires further study.

Molecular characterization of chicken-derived genotype VIId Newcastle disease virus isolates in China during 2005-2012 reveals a new length in hemagglutinin-neuraminidase.

Newcastle disease (ND) is one of the most important diseases of poultry, and causes severe economic losses in the global poultry industry. Although all Newcastle disease virus (NDV) isolates belong to a single serotype, significant genetic diversity has been described between different NDV isolates. Here, we report the molecular characterization of 23 virulent genotype VIId NDV isolates of class II circulating in China. Phylogenetic construction and analysis revealed the existence of distinctly genomic and amino acid differences that clearly distinguished these isolates from other typical NDV genotypes and vaccine strains. We also report a new 582-amino-acid hemagglutinin-neuraminidase in genotype VII NDV strains. This is believed to be the first study to investigate systematically the most predominant NDV strains, and provides more information on the genetic nature of genotype VIId NDV of class II circulating in China.