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Lin Z.-Z.,Jimei University | Lin Z.-Z.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering | Zhang H.-Y.,Jimei University | Peng A.-H.,Jimei University | And 5 more authors.
Food Chemistry | Year: 2016

Magnetic molecularly imprinted polymers (MMIPs) were synthesized through precipitation polymerization using malachite green (MG) as template, methacrylic acid as monomer, ethylene dimethacrylate as crosslinker, and Fe3O4 magnetite as magnetic component. MMIPs were characterized by scanning electron microscopy, Fourier transform infrared spectrometry, and vibrating sample magnetometry. Under the optimum condition, the MMIPs obtained exhibited quick binding kinetics and high affinity to MG in the solution. Scatchard plot analysis revealed that the MMIPs contained only one type of binding site with dissociation constant of 24.0 μg mL-1. The selectivity experiment confirmed that the MMIPs exhibited higher selective binding capacity for MG than its structurally related compound (e.g., crystal violet). As a sorbent for the extraction of MG in sample preparation, MMIPs together with the absorbed analytes could easily be separated from the sample matrix with an external magnet. After elution with methanol/acetic acid (9:1, v/v), MG in the eluent was determined by high-performance liquid chromatography coupled with UV detector with recoveries of 94.0-115%. Results indicated that the as-prepared MMIPs are promising materials for MG analysis in aquatic products. © 2016 Elsevier Ltd. All rights reserved.

Gao Z.-H.,Jimei University | Lin Z.-Z.,Jimei University | Lin Z.-Z.,Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering | Chen X.-M.,Jimei University | And 3 more authors.
Analytical Methods | Year: 2016

A facile and green hydrothermal method was developed for the preparation of highly luminescent nitrogen-doped carbon dots (NCDs) by using anhydrous citric acid and urea as the carbon source and nitrogen source, respectively. The NCDs show good water-solubility and exhibit excitation-independent fluorescence behaviors at excitations of 300-390 nm with a quantum yield of 42.5% at a λem of 440 nm. Based on the fluorescence quenching strategy, the NCDs were successfully applied to the measurement of Hg2+ in tap and lake water samples with high sensitivity and excellent selectivity. The detection limit was 7.3 nmol L-1 (3σ, n = 9), indicating its potential applications for the detection of trace Hg2+ in water samples. © The Royal Society of Chemistry 2016.

Han Y.,Xiamen University | Lei S.-L.,Xiamen University | Lu J.-H.,Xiamen University | He Y.,Xiamen University | And 5 more authors.
Materials Science and Engineering C | Year: 2016

A surface-enhanced Raman scattering (SERS)-assisted theranostic strategy was designed based on a synthesized multifunctional Fe3O4/Au cluster/shell nanocomposite. This theranostic strategy was used for free prostate specific antigen (free-PSA) detection, magnetic resonance imaging (MRI), and magnetic hyperthermia. The lowest protein concentration detected was 1 ng mL- 1, and the limit of detection (LOD) of the calculated PSA was 0.75 ng mL- 1. Then, MRI was carried out to visualize the tumor cell. Lastly, magnetic hyperthermia was employed and revealed a favorable killing effect for the tumor cells. Thus, this SERS-assisted strategy based on a Fe3O4/Au cluster/shell nanocomposite showed great advantages in theranostic treatment. © 2016 Elsevier B.V. All rights reserved.

Wang W.,Third Institute of Oceanography | Wang W.,Fujian Collab Innovation Center For Exploitation And Utilization Of Marine Biological Resources | Shao Z.,Third Institute of Oceanography | Shao Z.,Fujian Collab Innovation Center For Exploitation And Utilization Of Marine Biological Resources
Nature Communications | Year: 2015

Alkane-degrading bacteria are ubiquitous in marine environments, but little is known about how alkane degradation is regulated. Here we investigate alkane sensing, chemotaxis, signal transduction, uptake and pathway regulation in Alcanivorax dieselolei. The outer membrane protein OmpS detects the presence of alkanes and triggers the expression of an alkane chemotaxis complex. The coupling protein CheW2 of the chemotaxis complex, which is induced only by long-chain (LC) alkanes, sends signals to trigger the expression of Cyo, which participates in modulating the expression of the negative regulator protein AlmR. This change in turn leads to the expression of ompT1 and almA, which drive the selective uptake and hydroxylation of LC alkanes, respectively. AlmA is confirmed as a hydroxylase of LC alkanes. Additional factors responsible for the metabolism of medium-chain-length alkanes are also identified, including CheW1, OmpT1 and OmpT2. These results provide new insights into alkane metabolism pathways from alkane sensing to degradation. © 2014 Macmillan Publishers Limited. All rights reserved.

Yuan J.,State Oceanic Administration | Yuan J.,Xiamen University | Yuan J.,Fujian Collab Innovation Center For Exploitation And Utilization Of Marine Biological Resources | Lai Q.,State Oceanic Administration | And 7 more authors.
Frontiers in Microbiology | Year: 2015

The bacteria involved in organic pollutant degradation in pelagic deep-sea environments are largely unknown. In this report, the diversity of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria was analyzed in deep-sea water on the Southwest Indian Ridge (SWIR). After enrichment with a PAH mixture (phenanthrene, anthracene, fluoranthene, and pyrene), nine bacterial consortia were obtained from depths of 3946-4746 m. While the consortia degraded all four PAHs when supplied in a mixture, when PAHs were tested individually, only phenanthrene supported growth. Thus, degradation of the PAH mixture reflected a cometabolism of anthracene, fluoranthene, and pyrene with phenanthrene. Further, both culture-dependent and independent methods revealed many new bacteria involved in PAH degradation. Specifically, the alpha and gamma subclasses of Proteobacteria were confirmed as the major groups within the communities. Additionally, Actinobacteria, the CFB group and Firmicutes were detected. Denaturing Gradient Gel Electrophoresis (DGGE) analysis showed that bacteria closely affiliated with Alcanivorax, Novosphingobium, and Rhodovulum occurred most frequently in different PAH-degrading consortia. By using general heterotrophic media, 51 bacteria were isolated from the consortia and of these 34 grew with the PAH mixture as a sole carbon source. Of these, isolates most closely related to Alterierythrobacter, Citricella, Erythrobacter, Idiomarina, Lutibacterium, Maricaulis, Marinobacter, Martelella, Pseudidiomarina, Rhodobacter, Roseovarius, Salipiger, Sphingopyxis, and Stappia were found to be PAH degraders. To the best of our knowledge, this is the first time these bacteria have been identified in this context. In summary, this report revealed significant diversity among the PAH-degrading bacteria in the deep-sea water column. These bacteria may play a role in PAH removal in deep-sea environments. © 2015 Yuan, Lai, Sun, Zheng and Shao.

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