Association between the nasopharyngeal microbiome and metabolome in patients with COVID-19

SARS-CoV-2,the causative agent for COVID-19,infect human mainly via respiratory tract,which is heavily inhabited by local microbiota.However,the interaction between SARS-CoV-2 and nasopharyngeal microbiota,and the association with metabolome has not been well characterized.Here,metabolomic analysis of blood,urine,and nasopharyngeal swabs from a group of COVID-19 and non-COVID-19 patients,and metagenomic analysis of pharyngeal samples were used to identify the key features of COVID-19.Results showed lactic acid,L-proline,and chlorogenic acid methyl ester(CME)were significantly reduced in the sera of COVID-19 patients compared with non-COVID-19 ones.Nasopharyngeal commensal bacteria including Gemella morbillorum,Gemella haemolysans and Leptotrichia hofstadii were notably depleted in the pharynges of COVID-19 patients,while Prevotella histicola,Streptococcus sanguinis,and Veillonella dispar were relatively increased.The abundance of G.haemolysans and L.hofstadii were significantly positively associated with serum CME,which might be an anti-SARS-CoV-2 bacterial metabolite.This study provides important information to explore the linkage between nasopharyngeal microbiota and disease susceptibility.The findings were based on a very limited number of patients enrolled in this study;a larger size of cohort will be appreciated for further investigation.

A Convenient and Biosafe Replicon with Accessory Genes of SARS-CoV-2 and Its Potential Application in Antiviral Drug Discovery

SARS-CoV-2 causes the pandemic of COVID-19 and no effective drugs for this disease are available thus far.Due to the high infectivity and pathogenicity of this virus,all studies on the live virus are strictly confined in the biosafety level 3(BSL3)laboratory but this would hinder the basic research and antiviral drug development of SARS-CoV-2 because the BSL3 facility is not commonly available and the work in the containment is costly and laborious.In this study,we constructed a reverse genetics system of SARS-CoV-2 by assembling the viral cDNA in a bacterial artificial chromosome(BAC)vector with deletion of the spike(S)gene.Transfection of the cDNA into cells results in the production of an RNA replicon that keeps the capability of genome or subgenome replication but is deficient in virion assembly and infection due to the absence of S protein.Therefore,such a replicon system is not infectious and can be used in ordinary biological laboratories.We confirmed the efficient replication of the replicon by demonstrating the expression of the subgenomic RNAs which have similar profiles to the wild-type virus.By mutational analysis of nsp12 and nsp14,we showed that the RNA polymerase,exonuclease,and cap N7 methyltransferase play essential roles in genome replication and sgRNA production.We also created a SARS-CoV-2 replicon carrying a luciferase reporter gene and this system was validated by the inhibition assays with known anti-SARS-CoV-2 inhibitors.Thus,such a one-plasmid system is biosafe and convenient to use,which will benefit both fundamental research and development of antiviral drugs.

Pioneer to exploration and construction of Jilin Province s higher medical laboratory education and talent training system

Professor Tingbin Yang(杨廷彬)has dedicated his whole life to education science and microbiology research.He is not only an excellent microbiologist but also an outstanding educator.He has finished many professional books and got several honors for his job.Prof.Yang has contributed a lot for the development of medical laboratory education in China and clinical medicine.