Discovery of inhibitors against SARS-CoV-2 main protease using fragment-based drug design.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of coronavirus disease 2019 (COVID-19), in which the main protease (Mpro) plays an important role in the virus's life cycle. In this work, two representative peptide inhibitors (11a and PF-07321332) were selected, and their interaction mechanisms of non-covalently bound with Mpro were firstly investigated by means of molecular dynamical simulation. Then, using the fragment-based drug design method, some fragments from the existing SARS-CoV and SARS-CoV-2 inhibitors were selected to replace the original P2 and P3 fragments, resulting in some new molecules. Among them, two molecules (O-74 and N-98) were confirmed by molecular docking and molecular dynamics simulation, and ADMET properties prediction was employed for further verification. The results shown that they presented excellent activity and physicochemical properties, and had the potential to be new inhibitors for SARS-CoV-2 main protease.

A CRISPR-Cas12a-derived biosensor enabling portable personal glucose meter readout for quantitative detection of SARS-CoV-2.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread rapidly throughout the whole world and caused significant difficulties in the prevention and control of the epidemic. In this case, several detection methods have been established based on nucleic acid diagnostic techniques and immunoassays to achieve sensitive and specific detection of SARS-CoV-2. However, most methods are still largely dependent on professional instruments, highly trained operators, and centralized laboratories. These limitations gravely diminish their practicality and portability. Herein, a clustered regularly interspaced short palindromic repeats (CRISPR) Cas12a based assay was developed for portable, rapid and sensitive of SARS-CoV-2. In this assay, samples were quickly pretreated and amplified by reverse transcription recombinase-aided amplification under mild conditions. Then, by combining the CRISPR Cas12a system and a glucose-producing reaction, the signal of the virus was converted to that of glucose, which can be quantitatively read by a personal glucose meter in a few seconds. Nucleocapsid protein gene was tested as a model target, and the sensitivity for quantitative detection was as low as 10 copies/µl, which basically meet the needs of clinical diagnosis. In addition, with the advantages of lower material cost, shorter detection time, and no requirement for professional instrument in comparison with quantitative reverse transcription-polymerase chain reaction, this assay is expected to provide a powerful technical support for the early diagnosis and intervention during epidemic prevention and control.

Characteristics of recovered COVID-19 patients with recurrent positive RT-PCR findings in Wuhan, China: a retrospective study.

BACKGROUND: Two months after the outbreak of coronavirus disease 2019 (COVID-19) in Wuhan, China, tens of thousands of hospitalized patients had recovered, and little is known about the follow-up of the recovered patients. METHODS: The clinical characteristics, reverse transcriptase-polymerase chain reaction (RT-PCR) results from throat swab specimens and the results of serological COVID-19 rapid diagnostic test (RDT) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were retrospectively reviewed for a total of 758 recovered patients who were previously hospitalized in 17 hospitals and quarantined at 32 rehabilitation stations in Wuhan, China. RESULTS: In total, 59 patients (7.78%) had recurrent positive findings for COVID-19 on RT-PCR from throat swabs. With regard to antibody detection, 50/59 (84.75%) and 4/59 (6.78%) patients had positive IgG or dual positive IgG/IgM RDT results, respectively. CONCLUSIONS: Some patients who had been quarantined and had subsequently recovered from COVID-19 had recurrent positive RT-PCR results for SARS-CoV-2, and the possibility of transmission of the virus by recovered patients needs further investigation. TRIAL REGISTRATION: Current Controlled Trials ChiCTR2000033580 , Jun 6th 2020. Retrospectively registered.

Characteristics of Recurrent Positive RT-PCR Findings of Recovered Patients From COVID-19 in Wuhan, China: A Retrospective study (preprint)

After two month of the outbreak of corona virus disease 2019 (COVID-19) in Wuhan China, tens of thousands hospitalized patients, being recovered, little was known about the follow-up of the recovered patients. 758 recovered patients, hospitalized in 17 hospitals previously and quarantined in 32 rehabilitation post stations in Wuhan, China, were retrospectively reviewed for clinical characters, reverse transcriptase- polymerase chain reaction (RT-PCR) from throat swab specimens and serological COVID-19 rapid diagnostic test (RDT) for SARS-Cov-2. Among them, 59 patients (7.78%) had recurrent positive findings for COVID-19 on RT-PCR from throat swabs. Among the 50 patients which was effective samples for antibody detection, 45/50 (90.00%) and 4/50 (8.00%) patients had positive of IgG or dual positive of IgG/IgM RDT for COVID-19, respectively. A certain number of quarantined patients with COVID-19 had recurrent RT-PCR results of SARS-Cov-2, the possibility of transmission in the patients needs further investigation.