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The control of viral outbreaks requires nucleic acid diagnostic tests that are sensitive, simple and fast. Here, we report a highly sensitive and specific one-pot assay for the fluorescence-based detection of RNA from pathogens. The assay, which can be performed within 30–50 min of incubation time and can reach a limit of detection of 0.1-attomolar RNA concentration, relies on a sustained isothermal reaction cascade producing an RNA aptamer that binds to a fluorogenic dye. The RNA aptamer is transcribed by the T7 RNA polymerase from the ligation product of a promoter DNA probe and a reporter DNA probe that hybridize with the target single-stranded RNA sequence via the SplintR ligase (a Chlorella virus DNA ligase). In 40 nasopharyngeal SARS-CoV-2 samples, the assay reached positive and negative predictive values of 95 and 100%, respectively. We also show that the assay can rapidly detect a range of viral and bacterial RNAs., A one-pot enzymatic assay for the fluorescence detection of RNA accurately and rapidly detects specific viral and bacterial pathogens, as shown for SARS-CoV-2 RNA in clinical samples.

Recently, ω-transaminases have been increasingly used to synthesize amine compounds by reductive amination of prochiral ketones which are of high pharmacological significance. However, the conventional methods for evaluating these enzymes are time consuming and have often been regarded as a bottle neck in developing these enzymes as industrial biocatalysts. In the past few years, several high throughput screening methods have been developed for fast evaluation and identification of ω-transaminase. This review summarizes the various methodologies developed for rapidly screening ω-transaminases.