The active copper-containing carbon nanodots were prepared by hydrothermal method, and then characterized by fluorescence spectroscopy and UV-visible absorption spectroscopy.Subsequently, a highly sensitive and selective electrochemical biosensor was fabricated on the basis of this synthesized carbon nanodots with electro-deposition technique.The electrode behavior was investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry.Furthermore, the catalysis mechanism was studied.The experimental results indicated that the biosensor exhibited a strong electrocatalytic activity toward the oxidation of uric acid (UA).What′s more, the interference from ascorbic acid and dopamine was eliminated effectively.Under the optimum conditions, there were linear relationships between the anodic peak current and the concentration of UA (1.00-300.0 μmol/L), and the limit detection was 0.30 μmol/L (S/N=3).The prepared biosensor had advantages such as easy fabrication, strong anti-interference ability, high sensitivity, and wide detection range, and could be used for real sample detection.

Objective To prepare dual?modality single?photon emission computed tomography (SPECT)?MRI molecular nanoprobes targeting HAb18G/CD147 expressed on breast cancer cell membranes and investigate the physicochemical and biological properties in vitro. Methods Superparamagnetic iron oxide nanoparticles (SPIOs) were prepared by one?pot reaction method as described. The single?chain antibody fragments HAb18F(ab')2 were conjugated to SPIOs via chemical method and then labeled with 125I using Iodogen method. The final 125I?SPIO?HAbF18(ab')2 nanoprobes were purified. SPIOs or 125I?HAb18F(ab')2 were used as control. We carried preliminary evaluation on their physicochemical properties and biological characteristics in vitro: transmission electron microscope (TEM) and dynamic light scattering (DLS) were used to measure these nanoparticle sizes and the hydrodynamic diameters. The MRI T2 transverse relaxation efficiency of these nanoprobes at different Fe2+concentrations were measured with 1.5 T clinical MR scanner. The 125I?SPIO?HAb18F(ab')2 and 125I?HAb18F(ab')2 radiochemical purity were measured by thin layer chromatography and the radio chemical yield was calculated. We also conducted stability tests in vitro and octanol/water partition coefficient experiments. Two breast tumor cell lines, MDA?MB?231 (HAb18G?overexpressing cells,experimental group) and MDA?MB?468 (control), were used for assessment of cells viability at different Fe2 + concentrations (1, 5, 10, 20, 40 μg/ml) by methyl thiazolyl tetrazolium assay. Specific binding experiments in vitro included two parts:magnetic resonance imaging and radionuclide tests, the above?mentioned breast cancer cell lines were incubated with 125I?SPIO?HAb18F(ab')2 nanoprobes respectively and took MDA?MB?231 cells which were not treated as blank group. First comparing the MR signal intensity differences among experimental group, the control group and blank group, then calculated the rate of MRI signal changes;Two breast tumor cell lines, MDA?MB?231 and MDA?MB?468 were incubated with 125I?SPIO?HAb18F(ab')2 nanoprobes too, then measured radioactivity counting byγcounter at different time and calculated the cell binding rates, and did statistical analysis by using one?way ANOVA. Results The SPIOs were fairly homogeneous with an average core size of (10.32±1.30) nm;the SPIO and 125I?SPIO?HAb18F(ab')2 hydrodynamic diameter of 44.80 and 52.64 nm, and MRI scanning showed that the transverse relaxation efficiency of SPIO and 125I?SPIO?HAb18F(ab')2 were 38.79 and 106.73 mM-1 · s-1, respectively. The radio chemical yield of 125I?SPIO?HAbF18(ab')2 and 125I?HAb18F(ab')2 were 41.90% and 85.50%, respectively. The radio chemical yield of the two groups were >95%, suggesting well stability in vitro. The lipo?hydro partition coefficient values were -0.99 ± 0.03 and-1.49 ± 0.08, respectively, which demonstrated that they were both water?soluble substances. Different Fe2+concentrations (1,5,10,20,40μg/ml) of 125I?SPIO?HAb18F(ab')2 on breast cancer cell lines MDA?MB?231 and MDA?MB?468 showed no significant inhibition of cell proliferation (F values were 0.78, 0.66; P values were 0.58, 0.66). The cell?specific binding experiment showed: MRI signal intensity values on experimental group, the control group and the blank group were (1 670 ± 5), (1 930 ± 8), (2 349 ± 14), respectively, significant differences existed among these groups (F=4 408.48,P=0.000), the rate of signal intensity change of experimental group and the control group were 28.87%,17.78%. SPECT:MDA?MB?231 could uptake 125I?SPIO?HAb18F(ab')2, the cell binding rates were (6.52 ± 0.60)% and (10.52 ± 2.04)% in 20 min and 4 h, respectively.Conclusions Our results suggested that the dual?modality SPECT?MRI nanoprobes 125I?SPIO?HAb18F(ab')2 were prepared successfully with good physicochemical properties and biological characteristics in vitro. These dual?modality molecular imaging nano?probes may have potential to improvearly detection and diagnosis of HAb18G/CD147?expressing cancers and to facilitate the development of HAb18G/CD147?directed interventions.

ObjectiveCYP71 gene family is one of the CYP71 clans belonging to cytochrome P450， which plays an important role in secondary metabolites， especially terpenoid biosynthesis. To understand the characteristics of CYP71 family of diploid Perilla frutescens and predict its function， this study identified and systematically analyzed the family by bioinformatics. MethodOn the basis of the whole genome of diploid P. frutescens PC99， the conserved domains of CYP71 family of diploid P. frutescens were screened， and the sequence characteristics， gene structure， chromosome location， phylogeny and cis-acting elements were analyzed by National Center for Biotechnology Information （NCBI）， TBtools， MEME， Molecular Evolutionary Genetics Analysis （MEGA）， Cytoscape and other tools. ResultA total of 68 CYP71 genes were identified from diploid P. frutescens， which were unevenly distributed on 34 chromosomes and belonged to two subfamilies. They encoded 481-530 amino acids and contained 10 conserved motifs， with the isoelectric point of 5.70-9.03 and the molecular weight of 54 217.07-60 031.79 Da. The enrichment analysis and functional annotation analysis revealed 11 enriched pathways and 114 categories， and the genes were mainly annotated in biological processes. There were many cis-acting elements in the promoter region of CYP71， mainly light-responsive and methyl jasmonate-responsive elements. Protein-protein interaction analysis indicated that CYP71 protein had multiple functions such as terpene cyclase activity. ConclusionThis study lays a foundation for the functional study of CYP71 family， and provides a reference for the biosynthesis of monoterpenes in P. frutescens and the directional cultivation of excellent varieties.

ObjectiveThe biosynthetic pathways of benzylisoquinoline alkaloids（BIAs） in Nelumbo nucifera are of great theoretical and economic value. In this paper， N. nucifera O-methyltransferase（NnOMT） and N. nucifera N-methyltransferase（NnNMT） gene families were identified and analyzed by bioinformatics in order to facilitate the biosynthetic pathway of BIAs in N. nucifera. MethodBased on the whole genome of N. nucifera， UniPort and National Center for Biotechnology Information（NCBI） databases were used to identify the NnOMT and NnNMT gene families of N. nucifera， and analyze their physicochemical properties and subcellular localization， then TBtools， MEME， MEGA 11.0， FigTree 1.4.4 and other tools were used to analyze the phylogeny， sequence characteristics， gene structure， functional annotation and cis-acting elements of NnOMT and NnNMT genes identified in the previous stage. ResultA total of 61 NnOMT and NnNMT genes were identified in this paper， the number of amino acids encoded by these genes ranged from 168 aa to 580 aa， the isoelectric point ranged from 4.76 to 9.16， and the relative molecular weight ranged from 18 699.52 Da to 64 934.53 Da， most of which showed acidic and mostly hydrophilic proteins. There were 10 conserved motifs， Kyoto Encyclopedia of Genes and Genomes（KEGG） analysis enriched a total of 12 pathways， including metabolism， biosynthesis of phenylpropane and isoquinoline alkaloids， etc. And Visualization of Gene Ontology（GO） enrichment results showed that 61 NnOMT and NnNMT genes were annotated to 32 items， which included 16 molecular functions［such as reduced nicotinamide adenine dinucleotide（NADH） activity and exopeptidase activity］ and 16 biological processes（such as metabolic process of carbon tetrachloride， anaerobic carbon tetrachloride metabolic process and responses to exogenous biological stimuli）. There were a variety of cis-acting elements in the promoter regions of NnOMT and NnNMT genes， mainly promoter and enhancer regions element， light responsive element and methyl jasmonate responsive element. ConclusionIn this study， a comprehensive bioinformatics analysis of 61 NnOMT and NnNMT genes is carried out based on the genome data of N. nucifera， which lays a foundation for research on the gene structure and function of NnOMT and NnNMT gene families， and provides a reference for biosynthetic pathway elucidation of BIAs in N. nucifera.