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Objective@# To establish real-time recombinase polymerase amplification（RPA）for the rapid detection of Vibrio parahaemolyticus（VP）.@*Methods@#An exo probe and primers were designed according to the conserved sequence of thermolabile hemolysin（tlh）gene of VP and then RPA for detection of VP was established. The sensitivity of the assay was evaluated by detecting different concentration of VP;the specificity was evaluated by detecting different bacteria;the stability was evaluated by repeat trials;the application effect was evaluated by detecting food samples which were simultaneously tested with traditional culture method according to GB 4798.7-2013 Detection of VP.@*Results@#A real-time RPA was established to complete VP amplification within 20 min at a constant temperature of 39 ℃. The analytical sensitivity of the assay was five pg per reaction and no cross-reactivity with other pathogenic bacteria observed. The RPA detection results with different concentration of VP and E. coli DNA templates at three time points were consistent. The detection results of 51 food samples by RPA were the same as those by traditional culture method.@*Conclusion@#The established real-time RPA can qualitatively detect VP,with simple operation and interpretation of results,which is suitable for rapid detection of VP in public health emergencies and food safety supervision.
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Objective To discuss the antigenic change caused by the mutation of amino acid on the epitopes of the hemagglutinin of measles virus.Methods The B cell linear epitopes in the hemagglutinin were predicted with bioinformatics software.Peptide pairs,which located on the same region but originated from measles vaccine and wild-type virus respectively,were designed and synthesized.After detecting the immunogenicity of peptides with indirect ELISA assay,sera against each peptide was prepared.Antigenic specificity between the two peptides within each peptide pair were tested by using cross ELISA assay,and then antigen ratios were calculated.Results All the synthesized peptides could bind with immune sera against measles virus,of which the peptide pair CW23/CW22 designed on the epitope region (273-282 aa) possessed the highest binding ability,while the peptide pair CW150/CW151 designed on the non-epitope region (418-427 aa) showed the lowest binding ability.The difference in antigenic specificity between the two peptides from different sources was significant.The antigenic ratio was up to 16 between CW23 (vaccine-originated) and CW22 (wild-type originated),and 2.877 ± 0.583 between CW123 (vaccine-originated) and CW124 (wild-type originated) (236-246 aa).On the non-epitope regions,the antigenic ratios was only 1.631 ± 0.481 between peptide pair CW125 and CW126(356-364 aa),but reached to 10.367± 1.617 between CW150 and CW151.Conclusion Although there were several conservative epitopes,specific amino acid mutation on the predicted epitope or non-epitope regions might cause the antigenic change of wild-type measles virus.
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With the development of science and technology, new medical equipments is toward the direction of intelligent and portable. In order to assist medical personnel to patients with blood, developing from previous devices, a new kind of vein locating projection instrument based on two-dimensional scanning mirror is put forward. It can scan and project vein image using a scanning mirror. The related algorithm is also be improved, make vein scan projection more practical. The system finally set up can perform well in vein scan projection.