ABSTRACT
Previous work indicated that the nucleocapsid 203 mutation increase the virulence and transmission of the SARS-CoV-2 Alpha variant. However, Delta later outcompeted Alpha and other lineages, promoting a new wave of infections. Delta also possesses a nucleocapsid 203 mutation, R203M. Large-scale epidemiological analyses suggest a synergistic effect of the 203 mutation and the spike L452R mutation, associated with Delta expansion. Viral competition experiments demonstrate the synergistic effect in fitness and infectivity. More importantly, we found that the combination of R203M and L452R brings in a 3.2-fold decrease in neutralizing titers to the neutralizing serum relative to L452R-only virus. R203M/L452R show an increased fitness after the initiation of global vaccination programmes, possibly associated with the enhanced immune evasion. Another rapidly emerging variant Omicron also bears the 203 mutation. Thus, we proposed that nucleocapsid mutations play an essential role for the rise and predominance of variants in concern.
ABSTRACT
In addition to the mutations on the spike protein (S), co-occurring mutations on nucleocapsid (N) protein are also emerging in SARS-CoV-2 world widely. Mutations R203K/G204R on N, carried by high transmissibility SARS-CoV-2 lineages including B.1.1.7 and P.1, has a rapid spread in the pandemic during the past year. In this study, we performed comprehensive population genomic analyses and virology experiment concerning on the evolution, causation and virology consequence of R203K/G204R mutations. The global incidence frequency (IF) of 203K/204R has rose up from nearly zero to 76% to date with a shrinking from August to November in 2020 but bounced later. Our results show that the emergence of B.1.1.7 is associated with the second growth of R203K/G204R mutants. We identified positive selection evidences that support the adaptiveness of 203K/204R variants. The R203K/G204R mutant virus was created and compared with the native virus. The virus competition experiments show that 203K/204R variants possess a replication advantage over the preceding R203/G204 variants, possibly in relation to the ribonucleocapsid (RNP) assemble during the virus replication. Moreover, the 203K/204R virus increased the infectivity in a human lung cell line and induced an enhanced damage to blood vessel of infected hamsters lungs. In consistence, we observed a positive association between the increased severity of COVID-19 and the IF of 203K/204R from in silicon analysis of global clinical and epidemic data. In combination with the informatics and virology experiment, our work suggested the contribution of 203K/204R to the increased transmission and virulence of the SARS-CoV-2. In addition to mutations on the S protein, the mutations on the N protein are also important to virus spread during the pandemic.
ABSTRACT
The recent outbreak of a new zoonotic origin Coronavirus has ring the bell for the potential spread of epidemic Coronavirus crossing the species. With the urgent needs to assist the control of the Coronavirus spread and to provide valuable scientific information, we developed a coronavirus database (CoVdb), an online genomics and proteomics analysis platform. Based on public available coronavirus genomic information, the database annotates the genome of every strain and identifies 780 possible ORFs of all strains available in Genebank. In addition, the comprehensive evaluation of all the published genomes of Coronavirus strains, including population genetics analysis, functional analysis and structural analysis on a historical and global scale were presented in the CoVdb. In the database, the researcher can easily obtain the basic information of a Coronavirus gene with the distribution of the gene among strains, conserved or high mutation regions, possible subcellular location and topology of the gene. Moreover, sliding windows for population genetics analysis results is provided, thereby facilitating genetics and evolutional analysis at the genomic level. CoVdb can be accessed freely at http://covdb.popgenetics.net.
ABSTRACT
Objective:To evaluate the stability and bio-safety of warming moxibustion gel-unguentums( WMG) . Methods: With the commercially available package and at 40℃ ± 2℃, RH (75% ± 5%) for six months,the stability of WMG was inspected. Guinea pig skin sensitization test, rabbit skin irritation test and cell toxicity test were used to investigate the safety. Results:Compared to the results of 0 month, there was no difference in the sample character, containing paste percentage, adhesion, shape, weight difference and all theindices in TLC identification. Cell toxicity test showed that WMG had slight cytotoxicity. Guinea pig skin sensitization test and rabbit skin irritation test indicated that the grade of skin reaction was zero and the primary stimulus index of skin tissues was also zero. Conclusion:The quality of WMG is stable and the production preparation technology is feasible. Moreover, it is safe in transder-mal administration.
