Objective To fabricate an immunofluorescence probe system of carbon dots conjugated antibody based on antigen-antibody reaction principles.Methods A green one-step microwave assisted pyrolysis method was applied to preparing fluorescent carbon dots (CDs) using aminoglucose as carbon source and the obtained CDs were conjugated with antibody via EDC/NHS reactions to build CDs based fluorescent probe.Furthermore,the properties of CDs and CDs based probe system were evaluated by Fourier transform infrared (FTIR) spectra,transmission electron microscopy (TEM),UV-vis absorption and so on.Results The as-prepared CDs showed excellent fluorescence and hydrophilicity and CDs based immunofluorescence probe exhibited the capability of quick detection of E.coli O157:H7.Cinclusion Fluorescent CDs as one new emerging environment-friendly nanomaterial has great potential in biosensors.

Objective:To analyze the prevalence of different genotypes of wild measles virus in Fujian province from 2014 to 2019.Methods:The information of suspected measles cases and the throat swab specimens of the cases in Fujian province from 2014 to 2019 were collected. Reverse transcription-polymerase chain reaction was applied to amplify the 450 nucleotides of the 3-terminal of the nucleoprotein gene. Phylogenetic tree was constructed to identify and analyze the target sequence.Results:A total of 1 102 suspected measles cases were reported in Fujian province from 2014 to 2019, with an annual incidence rate of 0.47/100 000. Totally 884 throat swabs were tested in the laboratory, and 179 nucleotide sequences were obtained except vaccine strain. Sequence analysis showed that 110 measles genotypes were H1, 43 were B3 and 26 were D8. Nucleotide homology analysis showed that the H1a genotype measles virus in Fujian province distributed in two branches, divided into nine different sequence variants. Some of the variants were highly homologous (99.8%-100.0%) with the measles strains in other regions and countries. There were six different sequence variants of B3 genotype measles virus in Fujian province. The nucleotide homology between the B3 genotype measles virus in Fujian province and the domestic and foreign prevalent B3 strains was 98.4%-100.0%. The D8 genotype measles strain in Fujian province had five different sequence variants, some of which were highly homologous with the strains from Vietnam, Japan and Thailand.Conclusions:Three different genotypes of measles viruses (H1, B3 and D8) prevailed in Fujian province from 2014 to 2019, among which H1 genotype was still the local endemic genotype, while B3 and D8 genotypes were imported genotypes in Fujian province. The result indicated that although the local cases of measles were less in Fujian province in recent years, the risk of imported cases from abroad was increasing, and the surveillance of imported cases from abroad should be strengthened.