[Research on rapid detection technology of airborne pathogenic organisms based on up-conversion phosphor technology].

Objective: To explore the application of up-conversing phosphor technology (UPT) to detect pathogenic organisms in the air. Methods: The performance of UPT was verified with Staphylococcus aureus, Yersinia pestis and Escherichia coli O157 as simulated strains, including stability, specificity, sensitivity and response time tests; Air particle sampler is used to collect air samples in the field microenvironment test chamber, and UPT is used for detection. At the same time, compared with the traditional culture method, the practicability of UPT is verified. Results: The coefficient of variation in laboratory was 9.62% and 8.02% when the concentration of 107 CFU/ml and 108 CFU/ml were detected by UPT. The results were less than the allowable target, and the detection system had good stability. The specificity of UPT was verified by Staphylococcus aureus. The results showed that no non-Staphylococcus aureus was detected, and the positive detection rate of different kinds of Staphylococcus aureus was 100%. The specificity of the detection system was good. The sensitivity of UPT for detecting Staphylococcus aureus was 104 CFU/ml. Detection sensitivity of Yersinia pestis ≥103 CFU/ml; The detection sensitivity of Escherichia coli O157 is ≥103 CFU/ml, and the response time of UPT to bacteria is within 15 min (all 10 min 15 s). The detection results of bacteria contentration in the air of the on-site microenvironment test cabin by UPT showed that when the concentration of Escherichia coli O157 in the air reached above 104 CFU/m3, the detection results of UPT were positive, and with the increase of air concentration, the numerical concentration measured by UPT showed an upward trend, which was positively correlated with the concentration of bacteria in the air. Conclusion: UPT may be feasible as a rapid method to evaluate the species and contentration of pathogenic organisms in the air.

Gene knockout by inducing P-element transposition in Drosophila.

The P-element has been successfully used in germline transformation to create transgenic flies and as an insertion mutagenesis agent to disrupt genes. Moreover, P-element can also be used to knockout genes that are near the insertion sites by inducing its imprecise transposition. In this article, P-element insertion lines were crossed with transposase expression fly to recover the transposon, and the deletion of flanking sequence, which was created by imprecise excision, was detected by PCR. Through this method, null alleles of seven genes that spread over three major chromosomes (X, second, third) were generated in Drosophila melanogaster. Results show that the frequency of flanking deletions is expected to be 1%, and it is enough to pick up at least one ideal deletion line from 200 independent recovery lines in general. These data suggest that although the frequency of disrupted gene varied greatly, from 0.13 to 2.34%, gene knockout by inducing P-element transposition appears to be a feasible and effective strategy, compared to the complicated process of gene targeting based on homologous recombination.