Crystal structure of SARS-CoV-2 nucleocapsid protein RNA binding domain reveals potential unique drug targeting sites

The outbreak of coronavirus disease (COVID-19) caused by SARS-CoV-2 virus continually lead to worldwide human infections and deaths. Currently, there is no specific viral protein-targeted therapeutics. Viral nucleocapsid protein is a potential antiviral drug target, serving multiple critical functions during the viral life cycle. However, the structural information of SARS-CoV-2 nucleocapsid protein remains unclear. Herein, we have determined the 2.7 Å crystal structure of the N-terminal RNA binding domain of SARS-CoV-2 nucleocapsid protein. Although the overall structure is similar as other reported coronavirus nucleocapsid protein N-terminal domain, the surface electrostatic potential characteristics between them are distinct. Further comparison with mild virus type HCoV-OC43 equivalent domain demonstrates a unique potential RNA binding pocket alongside the -sheet core. Complemented by binding studies, our data provide several atomic resolution features of SARS-CoV-2 nucleocapsid protein N-terminal domain, guiding the design of novel antiviral agents specific targeting to SARS-CoV-2.

Study the mechanism of tantalum particles on the proliferation of osteoblasts / 实用医学杂志

Objective To investigate the effect of tantalum particles on the proliferation of osteoblasts and explore its mechanism. Methods Mouse osteoblasts MC3T3-E1 were co-cultured with micro-tantalum particles (micro-Ta)and Nano-tantalum particles(nano-Ta)of different concentrations respectively. CCK-8 assay was used to measure the cell viability at 6,12,24 and 48 h. According to the result of CCK-8 the group with the most prolif-erative effect was screened and the level of autophagy was detected by using Western blot,laser confocal microsco-py and transmission electron microscopy(SEM). Finally,to verify the role of autophagy in pro-proliferation effect of nano-Ta,the OD value was measured repeatedly in combination with autophagy inducer and inhibitor. Results 100 ng/mL micro-Ta treated groups had obvious proliferative effect but autophagy was not detected. 20 μg/mL nano-Ta treated groups had obvious proliferative effect and autophagy was detected. CCK-8 assay revealed that autophagy inhibitor can significantly inhibited cell proliferation of nano-Ta treated group. Conclusion Nano-Ta could pro-mote cell proliferation by inducing autophagy,and micro-Ta may promote osteoblast proliferation through other non-autophagy pathway.

Distribution of oral diseases in outpatient clinics:A Pareto analysis / 中华医学图书情报杂志

Objective To study the value of objective information transformation by analyzing oral diseases in outpa-tient department of our hospital and the diagnosis and treatment of oral diseases between expert clinic and outpatient clinic. Methods Oral diseases in over 50000 cases who visited the outpatient department of our hospital in 2015 were classified according to the ICD10 and analyzed by Pareto analysis. Results Dental carries, pulpitis, chronic periodontitis and dental crowding were the major diseases detected in outpatient department of our hospital, ac-counting for 80% of the total outpatients, and importance was thus attached to their treatment. Oral diseases re-ceived orthodontic therapy in expert clinic and received tooth implantation in outpatient clinic. Conclusion Hospi-tals should scientifically allocate their medical resources, strengthen the training of their young dentists, bring into full play of their limited medical resources according to the distribution of oral diseases in their outpatient depart-ments in order to meet the increasing demand of oral healthcare.