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CRISPR-based assays for the detection of nucleic acids are highly specific, yet they are not fast, sensitive or easy to use. Here we report a one-step fluorescence assay for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in nasopharyngeal samples, with a sample-to-answer time of less than 20 minutes and a sensitivity comparable to that of quantitative real-time PCR with reverse transcription (RT-qPCR). The assay uses suboptimal protospacer adjacent motifs, allowing for flexibility in the design of CRISPR RNAs and slowing down the kinetics of Cas12a-mediated collateral cleavage of fluorescent DNA reporters and cis cleavage of substrates, which leads to stronger fluorescence owing to the accumulation of amplicons generated by isothermal recombinase polymerase amplification. In a set of 204 nasopharyngeal samples with RT-qPCR cycle thresholds ranging from 18.1 to 35.8, the assay detected SARS-CoV-2 with a sensitivity of 94.2% and a specificity of 100%, without the need for RNA extraction. Rapid and sensitive assays for nucleic acid testing in one pot that allow for flexibility in assay design may aid the development of reliable point-of-care nucleic acid testing.

Helicobacter pylori infection is an essential factor in the development of human gastric diseases, but its pathogenic mechanism is still unclear. In this work we have showed that, the LC3II levels were increased and β1-integrin levels were decreased in H. pylori-positive human gastric tissue samples and H. pylori co-cultured GES-1 cells. There was significant upregulation of LC3II levels and downregulation of P62 levels in GES-1 cells after β1-integrin knockdown co-cultured with H. pylori. This indicated that β1-integrin downregulation promoted autophagy in GES-1 cells after H. pylori infection. The cell apoptosis rate and poly ADP-ribose polymerase (PARP) and caspase-3 activities were increased in GES-1 cells pretreated with 3-methyladenine (3-MA ) after H. pylori infection. Furthermore, there was a significant decrease in apoptosis of β1-integrin knockdown GES-1 cells co-cultured with H. pylori; apoptosis was also downregulated in β1-integrin knockdown- and 3-MA-treated GES-1 cells co-cultured with H. pylori. Correspondingly, PARP and caspase-3 activities were decreased in β1-integrin knockdown cells co-cultured with H. pylori and β1-integrin knockdown-3-MA-treated-1 cells with H. pylori infection. Thus, β1-integrin is a novel autophagy and apoptosis regulator during H. pylori infection. However, inhibition of autophagy did not reverse the decrease in apoptosis caused by downregulation of β1-integrin.