Why is the new crown otter variant in focus?

recently, the Danish government said it would kill nearly 17 million otters in the country, causing widespread concern from all walks of life. That's because on November 4th the Danish government announced that a mutant strain of coronavirus had been infected from otters to humans. According to a report by denmark's State Serum Institute (SSI), 12 people have been infected with the new strain, which has a weak antibody response. SSI officials say the mutant strain is no more dangerous than other new coronavirus strains, but they suggest that existing vaccines may not be sensitive to the strain. Currently, several organizations, including WHO and the European Centre for Disease Control and Prevention, recommend targeted measures in EU/EEA countries and the UK.

, what are the mysteries of the otter mutant?A study by SSI looked at the characteristics of the new coronavirus mutant strain. The researchers isolated five mutant strains, cluster1 to cluster5, in the Danish otter, causing a variety of amino acid mutations on the Spike protein. The Y453F mutation is of great significance.The amino acid in the 453rd bit of the Y453F mutant new coronavirus Spike protein is changed from tyrosine (Y) to phenylalanine (F), a conservative amino acid replacement in the receptor binding region, which is directly in contact with the 34-bit amino acid of the host ACE2 receptor. ACE2 is 34th in the human body for histamine (H) and tyrosine (Y) for otters, so it is assumed that this mutation is intended to be more adaptable to otter hosts. But at the same time, the researchers found that 453F increased affinity for human ACE2, which may be the reason the virus invades the human body, which explains why the new coronavirus can be transmitted from otters to humans.In addition to the Y453F mutation, it includes: 1) 69-70 deltaHV, which is missing histamines and prolines in the 69th and 70th bits of amino acids in the S1 sub-base N-end region; The point is a conservative replacement of 692 bits, a 7 amino acid located downstream of the furin cleavage point;SSI researchers obtained two separate strains of otter mutations, one containing the Y453F mutant strain (F-spike) and the other containing 69-70 deltaHV, 453F, 692V, and 1229I mutant strains (FVI-Spike). Through culture, it was found that after 24 hours, the virus titration of FVI-spike was only one-tenth that of F-spike mutants and wild strains, but after 96 hours, the virus titration of FVI-spike was close to that of wild type. The titration of the FVI-spike strain increased by 54.7 times during this period, while the other strains increased only four times on average (in the range of 2.6-5.7 times).Mutations in the SARS-COV-2 Spike protein raise concerns that the effects of these mutations on viral infections or vaccinations are uncertain and may reduce the ability of antibodies to recognize the protein. So SSI scientists conducted experiments on the mesoactive activity of the mutant strain FVI-spike in plasma and immune rabbits/rats in rehab. The effects of mutations in Spike proteins on different concentrations of meso-antibodies are unknown, so the researchers tested them with samples of different mesothropials. The results showed that the high school and titration samples were largely unaffected by the mutant strains, but the medium- and low-titration samples were significantly affected by the mutant strains and the moderate activity decreased. In the nine plasma samples tested, the average mesoactive activity decreased by 3.58 times (0-13.5 times), and in two plasma, the activity decreased by more than four times. SSI scientists call these experiments preliminary studies and call for more in-depth scientific validation.9 days Yiju Shenzhou successfully expressed Y453F mutant proteinIn order to support researchers to speed up the research of the new coronavirus mutation in otters, Yiju Shenzhou only took 9 days to successfully express the new coronavirus Y453F mutant recombinant protein (no. 40592-V08H80). The protein was detected by SDS-PAGE electrophoresis to be more than 95% pure. ELISA analysis shows that the protein is biologically active and binds to ACE2.All otter sequences contain D614G mutationsand in this work paper, it is also mentioned that all otter SARS-COV-2 sequences tested contain D614G mutations. In the course of the pandemic, the new coronavirus is constantly evolving, especially with the D614G mutation of the new coronavirus has become the main strain infected around the world. A recent article in the journal Science confirmed that the D614G mutation in the new coronavirus infection model enhances the spread of the virus.

Yihua Shenzhou has established the world's leading antigen library of new coronavirus mutant strains, and has now put 68 RBD mutant proteins online, as well as HPLC-validated D614G mutant proteins, to support researchers in the study of the impact of mutant strains on the spread of new coronavirus, clinical, diagnostic, vaccine and drug development. (Biological Exploration): 1.SARS-CoV-2 Spikes mutations arising in Danish mink and spread to humans. Working paper of SSI.2.COVID MINK ANALYSIS SHOWS MUTATIONS ARE NOT DANGEROUS — YET. Nature. Vol 587.19 November 2020.3.Y. J. Hou et al., (2020) SARS-CoV-2 D614G variant exhibits efficient replication ex vivo and transmission in vivo. Science, 10.1126/science.abe8499