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Quinclorac (QNC) is a persistent, highly selective, hormonal herbicide of low toxicity. QNC accumulates in soil and affects the growth and development of crops planted subsequent to its application. In this study, we isolated and screened a QNC-degrading bacterial strain, strain D, from rice paddy soil. Morphological analysis, physiological and biochemical tests, and 16S rRNA gene sequencing led us to identify strain D as a Cellulosimicrobium cellulans strain. We investigated the characteristics of strain D in relation to QNC degradation. Under optimal culture conditions, the QNC degradation rate was 45.9% after 21 days of culture. QNC degradation by strain D in the field was modeled and quantified by a pot experiment. The results show that strain D promotes rice growth and degrades QNC. This research has identified a new bacterial species that degrades QNC, providing a foundation for further research into QNC remediation. IMPORTANCE QNC-degrading bacteria have been isolated from different environments, but there are no reports of Cellulosimicrobium cellulans strains that degrade QNC. In this study, a previously unidentified bacterial strain that degrades QNC, strain D, was screened from paddy soil. The characteristics of strain D that relate to QNC degradation were investigated in detail. The results showed that strain D effectively degraded QNC. Two degradation products of QNC formed by strain D that have not been reported previously, i.e., 3-pyridylacetic acid (m/z 138.0548) and 3-ethylpyridine (m/z 108.0805), were identified using high-performance liquid chromatography–quadrupole time of flight mass spectrometry. Strain D has the capacity to degrade QNC in a QNC-polluted paddy.

An electrochemical N-acylation of carboxylic acids with amines was reported. The sustainable TBAB electrocatalysis proceeded with excellent chemoselectivity and positional selectivity, and with ample scope, allowing electrochemical N-acylation under mild reaction conditions at room temperature in water. Moreover, the synthetic utility of the current method is demonstrated by the synthesis of melatonin.

An efficient and convenient Ni-catalyzed C–N bond formation for the synthesis of various benzimidazoles from various 2-haloanilines, aldehydes, and ammonia in a concise manner is reported. This protocol uses commercially available, nonhazardous, clean ammonia as a reaction partner instead of other nitrogen sources. Benzimidazoles, as the sole products, were obtained in high to excellent yields (up to 95%).

Low-abundance proteins (LAPs) play a very important role in interaction, regulation, and metabolism of plant biological processes. A combinatorial peptide ligand library (CPLL) can solve the problem of high-abundance proteins (HAPs) masking LAPs and enlarging the dynamic range of protein concentrations perfectly and be considered as one of the most advanced approaches for plant proteomics research. In this paper, a proper CPLL method to rice leaf proteins was established for the first time and 1056 proteins were identified in rice leaf extracts, and 624 (59.1%) LAPs were newly detected after CPLL. Based on this technology, we detected the response of rice to Cd stress and analyzed the differential LAPs and the biological significance of misexpressed proteins before and after Cd stress by bioinformatics analysis. An important contribution has also been made to a better understanding of the complex mechanisms by which rice adapts to Cd stress. Graphical abstract.

An efficient copper-catalyzed three-component reaction of 2-haloaniline, ammonia and aldehyde for the synthesis of benzimidazoles with 1,10-phenanthroline as the ligand has been developed. A variety of substituted benzimidazole derivatives can be obtained in yields up to 95%.

Atmospheric particulate matter (PM) pollution is a serious threat to human health, so the preparation of electret films with high efficiency and low resistance capturing particulate has attracted wide attention. Herein, a strategy for the fabrication of all-polymer hybrid electret fiber membranes by electrospinning is reported based on the ethyl cellulose (EC) and polystyrene (PS). The preparation conditions of electret fiber membrane were optimized by focusing on the effect of the mass ratio of EC/PS and the spinning time on the structure, surface potential and purification performance of fiber membrane. The result showed that the fiber membrane has a low fiber diameter of 572 ± 113 nm and porosity of 82.4%, and a better potential stability when the EC/PS mass ratio was 2.5/1 and the spinning time was 10 min. As a result of the enhanced effect of electrostatic attraction on particle capture, the EC/PS composite electret membrane could make the purification efficiency of PM2.5 reach to100% within 11 min. Moreover, the EC/PS composite electret membrane has the properties of ultra-light base weight of 1.08 g·m−2, low air resistance of 28 Pa and long service life. Therefore, the all-polymer EC/PS electret nanofiber membranes have broad application prospects in the field of air purification.

Conventional water-based foam decontaminants used for the removal of radionuclides lose their efficacy in winter at temperatures below 0 °C. To address this problem, an antifreeze foam, with characteristics of good stability, high decontamination efficiency, less liquid waste generation, and excellent biodegradability, was developed using a biomass-based surfactant, a polysaccharide foam stabilizer, and an antifreeze agent. Furthermore, the surface tension, solution viscosity, foam stability, and decontamination of simulated radionuclides on different plates of a xanthan gum (XG)-stabilized antifreeze foam at temperatures ranging from −10 °C to 10 °C were investigated. Especially, the bulk-phase performance and stabilizing mechanism of the antifreeze foam were analyzed. Compared with the antifreeze foam without stabilizer, the half-life of the XG-stabilizing foam increases from 30.5 min to 2785 min, and the initial drainage time increases from 5 min to 383.5 min at −10 °C, which considerably extends the decontamination time and is conducive to improving the decontamination efficiency. Furthermore, the foam stability and bulk viscosity of the foam solution at a low shear rate exhibited a significant positive correlation. As a result, with decreasing the temperature, the viscosity of the XG-stabilized antifreeze foam solution increased leading to a better stability of foam at a lower temperature. The stabilizing mechanism of the XG stabilizer would possibly be the rigid chain structure of the XG molecule, which could lightly resist the contraction and bending of the molecular chain caused by Na+ originated from the surfactant sodium alpha-olefin sulfonate (AOS) and H+ originated from acidic chelator citric acid (CA) in the decontamination foam. Another probable stabilizing mechanism would be that the electrostatic repulsion generated by the negatively charged groups on the XG molecular chains could prevent the molecular aggregation and precipitation. Moreover, surface decontamination results revealed that the XG-stabilized antifreeze foam can remove >90% of the radionuclide contamination physically attached to surfaces of glass, stainless steel, white paint, green paint, and tile plate below 0 °C. Therefore, the antifreeze foam detergent exhibits good application potential for the decontamination of surface radioactive contamination in winter due to its excellent stability, high decontamination efficiency, and biodegradability.

Background Plant glutathione S-transferases (GSTs, EC 2.5.1.18) are multifunctional enzymes involved in heavy metal cellular detoxification by conjugating the tripeptide (g-Glu-Cys-Gly) glutathione to heavy metals. Previous studies demonstrated that individual rice GSTs were differentially induced by heavy metal exposure at the mRNA transcript level. However, little information is available concerning changes in protein concentration of rice GSTs under heavy metal stress. Because the correlation between changes in protein concentration and gene expression under abiotic stress is poor, direct determination of rice GSTs protein concentrations during cadmium (Cd) exposure is a more effective and reliable approach to explore possible mechanisms of rice Cd translocation and accumulation. Results This study established an optimized and advanced liquid chromatography–tandem mass spectrometry (LC–MS/MS)-based targeted proteomics assay for quantification of OsGSTF14 and OsGSTU6 proteins in Cd-stressed rice roots. The tryptic signature peptides were chosen as surrogate analytes and winged peptides containing the isotope-labeled signature peptides were used as the internal standards. The signature peptides exhibited good linearity in the range of 0.6–60 and 0.3–30 nM, respectively. The limit of detection and limit of quantification were 4.5 and 14.5 µg/g for OsGSTF14, respectively, and 2.1 and 7.0 µg/g for OsGSTU6. The spiking recoveries rates at low, medium and high levels were in the range of 72.5–93.4%, with intra- and inter-day precisions of 5.5–9.1 and 4.2–10.2%, respectively. Conclusions The assay successfully quantified the temporal and dose responses of OsGSTF14 and OsGSTU6 proteins in Cd-stressed rice roots, with good accuracy, precision and high-throughput. This assay will have significant application in developing quantification methods of other proteins in Cd-stressed rice, which may provide more insight into the mechanisms of Cd translocation and accumulation in rice. Electronic supplementary material The online version of this article (doi:10.1186/s13007-017-0214-2) contains supplementary material, which is available to authorized users.

Cadmium (Cd) pollution is a serious widespread environmental problem that not only destroys the microbial ecology of soil and decreases crop production, but also poses a serious risk to human health. Many methods have been used for the remediation of Cd pollution but none of these is totally satisfactory. Microbial remediation strategies have attracted increasing interest since they are environmentally friendly and cost-effective. In the present study, three Cd-resistant bacteria were isolated and evaluated for potential application in Cd bioremediation. Based on their morphological, physiological and biochemical characteristics, together with 16S rDNA gene sequence analyses, bacteria were identified as Stenotrophomonas acidaminiphila (2#), Pseudomonas aeruginosa (9#) and Delftia tsuruhatensis (12#). Pseudomonas aeruginosa showed very high tolerance to metals, especially Cd (2200mg/L), Zn (1800mg/L) and Pb (1200mg/L), and is thought to be a multi-metal-resistant bacterium. Pseudomonas aeruginosa was also sensitive to 13 different antibiotics. The effects of the bacterial strains on the growth of rice plants and their ability to reduce Cd accumulation from Cd-contaminated soils in pot experiments were also evaluated. For Oryza sativa L. A grown in contaminated soil (3mg/kg Cd), the accumulation of Cd was decreased by 31.2 and 25.5% in brown rice and polished rice, respectively, by strain 9#; Pseudomonas aeruginosa was more effective in reducing Cd accumulation in rice grains than a mixture of strains. For Oryza sativa L. B, a mixture of strains acting synergistically was more effective than a single strain in reducing Cd accumulation; treatment with mixed strains (strains+3mg/kg Cd) resulted in 41.3, 35.9, and 32.6% reductions in Cd accumulation in unhulled rice, brown rice and polished rice, respectively. Although different results were obtained for two rice varieties, it can still be concluded that Cd-resistant bacteria are suitable for reducing Cd accumulation in rice grains and show potential for bioremediation of Cd-contaminated soils.

In this work, we propose a new approach to create striped patterned sapphire substrate (PSS) under the circumstance that grooved patterned sapphire substrate technology exhibits more potential to reduce dislocation density in GaN (gallium nitride) epilayers. The striped grooves of patterned sapphire substrate are ablated by femtosecond laser. After the process of metal-organic chemical vapor deposition (MOCVD) method, the c-plane GaN epitaxial layers grown on striped PSS have larger crystallite size, which brings much less crystal boundary. There is much less compressive stress between the GaN crystals which improves the smoothness and compactness of GaN epilayers. This result demonstrates a significant improvement in the crystallinity of the c-plane GaN epitaxial layers grown on striped PSS.

The flower-like porous In2O3 pompon assembled from two-dimensional (2D) nanosheets was synthesized through a simple thiourea-assistant hydrothermal method following the annealed process. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images manifest that the In2O3 pompon possesses a clear porous structure with a nanosheet thickness of about 37.5 nm. Further, we compare the performance of intermediate products (In2S3, In2S3/In2O3) and In2O3 nanostructures as ethanol detection gas sensors. The fabrication of In2O3-based sensors exhibits enhanced ethanol sensing performance than that of In2S3/In2O3-based and In2S3-based sensors, which is mainly attributed to more chemical oxygen and oxygen vacancies on the material surface. The In2O3-based sensors for ethanol detection revealed a wide linear range from 2 ppm to 100 ppm, meanwhile the corresponding detection limits (LOD) as low as ~0.4 ppm at 260 °C. And the In2O3-based sensors also exhibit superior repeatability and reliable selectivity. The simple fabrication strategy of 2D nanosheets-assembled flower-like In2O3 porous pompon may facilitate other ethanol gas sensors production and other 2D metal oxide semiconductor materials-based sensors preparation.

Porous zirconium alginate beads as a novel adsorbent were prepared for fluoride removal and characterized by SEM, FTIR, TG, EDX and XPS. The effect of solution pH, adsorbent dose, initial fluoride concentration, contact time, medium temperature and the coexisting ions on adsorption capacity of fluoride ion has been studied. The presence of HCO3−, SO42− and PO43− had a large negative impact on fluoride removal. The kinetics of fluoride ion adsorption onto porous zirconium alginate was followed the pseudo-second-order with correlation of 0.9953. The isotherm data were well fitted to the Langmuir isotherm model and the maximum capacity was 32.797 mg g−1. The values of ΔH0, ΔS0 and ΔG0 were calculated and the results indicated that the process of fluoride adsorption was exothermic and spontaneous. The comparison between porous zirconium alginate and other adsorbents suggested that porous zirconium alginate beads possessed a potential for fluoride removal.

Sulfur (S) fertilizer application in rice (Oryza sativa L.) is crucial in determining rice grain productivity and quality. However, little information is available concerning the effect of S supply on cadmium (Cd) uptake and translocation in rice. In this study, both hydroponic and soil experiments were conducted to investigate the influence of S supply on Cd accumulation in rice under two Cd levels (0 and 50 μM), combined with three S concentrations (0, 2.64 and 5.28 mM). The moderate and excessive S supply (2.64 and 5.28 mM) tended to increase plant growth, root length, root and shoot dry weights of rice seedlings, and significantly decreased Cd concentrations in rice plants and grains in the absence or presence of Cd. The subcellular distribution and chemical forms of Cd in roots and shoots also varied with S supply levels. The decreased Cd uptake and translocation in rice grains could be ascribed to the enhanced formation of iron (Fe) plaque on the root surfaces and increased Cd chelation and vacuolar sequestration in roots, since Fe, Mn concentrations in Fe plaque, glutathione and phytochelatins contents, as well as phytochelatin synthase (OsPCS) and tonoplast heavy metal ATPase (OsHMA3) expressions in roots significantly increased with increased S supply. This work provides more insight into the mechanisms of Cd uptake and translocation in rice, and will be helpful for developing strategies to reduce rice grain Cd through S fertilizer application in Cd-contaminated soil.

Nickel (Ni) concentrations in milled rice obtained from China and their variations among different provinces and varieties, as well as associated health risks, were investigated. Results showed that the mean Ni concentration in milled rice was 0.49 ± 0.51 mg/kg, which was much higher than reported in United Kingdom, French and Iranian cereals. There were significant variations (P

Ustiloxins are cyclopeptide mycotoxins produced by the pathogenic fungus Ustilaginoidea virens of rice false smut. Quantification of ustiloxins is essential to assess the food safety of rice infected by rice false smut disease. This paper describes a sensitive method for the simultaneous quantification of ustiloxins A, B, C, D and F in rice grains using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Since notable matrix enhancement effects (21%-78%) occurred for all of the target analytes (except for ustiloxin A), several solid phase extraction materials were tested for their ability to retain ustiloxins from aqueous solutions prior to the LC-MS/MS analysis, including C18 sorbents, polymer anion exchange sorbents resin (PAX), and polymer cation exchange resin (PCX). The PCX resin was adopted due to its higher extraction capability and selectivity for all targets compared to others, and in this case, almost no matrix effects (-5% to 8%) were observed for all of the ustiloxins monitored. The developed method reached limits of quantification of 0.2-2ngg-1, and linearity was statistically verified over two orders of magnitude with regression coefficients (R2)>0.991. The mean recoveries were from 85% to 109%, and the inter-day precisions (n=11) were less than 16%, with intra-day precisions (n=6) within 12%. Analysis of samples showed that ustiloxin A was the dominant species, with the content ranging from 5.5 to 273.8ngg-1, followed by ustiloxin B (≤88.7ngg-1), while concentrations of ustiloxins C, D and F were slightly lower (≤43.2ngg-1). To our knowledge, this is the first report on the determination and analysis of five ustiloxins simultaneously in a single analysis.

A sensitive method was developed for the simultaneous identification of five ustiloxins in the false smut balls of rice by high performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry (HPLC-LTQ/Orbitrap MS). The samples were extracted with deionized water under ultrasonic condition for 10 min, then purified by a strong cation exchange column (PCX). The ustiloxins were separated on an Xselect HSS T3 column (150 mm x 2.1 mm, 3.5 μm) by using 0.1% (v/v) formic acid water solution and methanol as mobile phases with gradient elution at a flow rate of 0.3 mL/min. The full scan range was m/z 200-1 000. The confirmatory analysis of the target compounds was carried out by the accurate mass of quasi-molecular ion, isotope abundance ratio and qualitative fragments. The results showed that the five ustiloxins (A, B, C, D and F) were identified from the false smut balls with mass accuracy less than 1 x 10(-6) (1 ppm) and the absolute values of the deviation of isotope abundance ratio were not more than 3.3%. The product ions were consistent with the theoretical fragment mode. The recoveries were 90% to 105%. This method is accurate and sensitive for the simultaneous identification of the five ustiloxins, which can provide technical means for the research of the ability in toxin producing by Ustilaginodea virens.

A high-throughput method was developed using liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) for the profiling and quantification of 43 phytohormones and their major metabolites, including auxins, abscisic acid, jasmonic acid, salicylic acid, cytokinins and gibberellins in a single sample extract. Considerable matrix effects (MEs) were observed (with most ME values in the range of 29%-84%, but maximum MEs of more than 115%, even up to 206%, existed) in sample extracts for most of the compounds studied. The application of the proposed binary solid-phase extraction using polymer anion and polymer cation exchange resins, was performed to purify 25 acidic and 18 alkaline phytohormones and their major metabolites prior to the LC-MS/MS analysis, which markedly reduced the MEs to acceptable levels, with ME values in the range of ±15%. Moreover, all of the isomers of cytokinins and their metabolites were fully separated on a sub-2μm particle C18 reverse-phase column with the optimized mobile phase consisting of methanol and 5mM ammonium formate. The method showed good linearity for all 43 analytes with regression coefficients (R(2))>0.991. Limits of detection ranged from 0.19 to 7.57 fmol for auxin, gibberellins, abscisic acid and their metabolites, 29.7 fmol for jasmonic acid, 18.1 fmol for salicylic acid, and from 0.03 to 0.31 fmol for cytokinins and their metabolites. The mean recoveries for all of the analytes were from 70.7 to 118.5%, and the inter-day precisions (n=6) were less than 18.7%, with intra-day precisions (n=6) within 25.4%. Finally, 20 compounds were successfully quantified in rice sample profiles using the proposed method, which will greatly facilitate the understanding of hormone-related regulatory networks that influence rice growth and development. To our knowledge, there are limited reports that measure this level of phytohormone species in rice samples using a single analysis.

Thermoplastic of carboxy methyl cellulose graft methyl acrylate (CMC-g-MA) using ammonium per sulfate (APS) as an initiator was carried out in an aqueous solution. The percentage grafting percentage (%G) is affected by increasing reaction time, concentration of monomer and initiator, and reaction temperature. These graft copolymers were characterized by infrared spectroscopy, differential scanning calorimetry. Experiments showed that the optimal conditions for grafting were: ammonium per sulfate of 150 mg, methyl acrylate of 40 mL, reaction time of 4 hour and temperature of 70 iaC.

The adsorption performance of aminoalky cellulose (AmAC) for 2,4,6-trinitrotoluene (TNT) was investigated in afixed bed column. The fixed bed column parameters such as bed height, flow rate, influent TNT concentration were studied by a series of dynamic adsorption experiments. The result showed AmAC was an effective adsorbent for removal of TNT, and the equilibrium uptake increased from 27.76 to 36.18 mg/g when the bed height increased from 4.5 to 7.3 cm at flow rate of10mL/min and influent TNT concentration of20mg/L. The equilibrium uptake decreased from38.01 to 22.03 mg/L with increasing of flow rate from 10 to 20 mL/min. As influent concentration increased from 20 to 80 mg/L, the equilibrium uptake increased from 31.69 to 52.20 mg/g. The minimum column height of 2.3 cm was calculated by the bed depth service time (BDST) at flow rate of 10 mL/min and influent TNT concentration of20mg/L.