According to the French newspaper Le Monde, the French Pasteur Institute reported that bat coronavirus, which is the closest to the new crown virus to date, has the closest bat coronavirus to the new crown virus in northern Laos, which has common key characteristics with the new crown virus and may have an evolutionary relationship with the new crown virus. This study provides clues to the origin of the new crown virus, and also brings scientists closer to determining the origin of the new crown virus. The study was published Sept. 18 in Research Square, The Nature's preprint platform.
Researchers are highly concerned about the spike protein sequence on the surface of the new coronavirus, and the receptor-binding domain (RBD) of the spike protein invades the human body by binding to the human cell receptor "angiotensin-converting enzyme 2 (ACE2)".
In previous studies, the RaTG13 bat coronavirus found in China was the closest to the new coronavirus, with 96.2% homology to the genomes of the two viruses. The RaTG13 virus has RBD, but its genetic sequence bears little resemblance to the RBD gene sequence of the new coronavirus. Of the 17 amino acids of RatG613 coronavirus RBD, only 11 are the same as those of the new coronavirus. The raTG13 virus's ability to bind RBD to human ACE2 receptors is also limited.
Therefore, there is a key question that needs to be solved in the traceability study of the new crown virus, that is, whether there is a bat coronavirus with a similar RBD gene sequence to the new crown virus on its spike protein and is able to bind to human ACE2 receptors with high affinity.
The report pointed out that the coronavirus was found in bats in Laos, and its RBD was only one or two amino acids apart from the RBD of the new coronavirus, and it was able to strongly bind to human ACE2 receptors and infect human cells.
In the new study, researchers from the Institut Pasteur in France and the University of Laos captured 645 bats from 46 species in the limestone karst zone of northern Laos between July 2020 and January 2021, collecting 247 blood samples, 608 saliva samples, 539 swabs/stools and 157 urine swabs. The researchers conducted a sampling study of whether the coronavirus carried by these bats was similar to the new coronavirus. In the end, a total of 3 bat coronaviruses that were highly similar to the new coronavirus RBD were found in the samples.
The researchers note that the virus, code-named BANAL-52, BANAL-103 and BANAL-236, is the "closest known" bat coronavirus to the coronavirus. Among them, THE BANAL-236 virus has almost the same RBD as the new crown virus, with only two residues, the difference is only two residues; 16 of the 17 amino acids of BANAL-52 and BANAL-103 virus RBD are the same as the new crown virus; the genome of BANAL-52 and the new crown virus have 96.85% homology.
Mark Eloyt, one of the authors of the paper and head of the field of pathogen exploration at the Pasteur Institute, said that these three bat coronaviruses may be the source of the new crown virus and may pose a real risk of direct transmission to humans, and the newly discovered coronavirus seems to have the same ability to infect humans as the early strains of the new crown virus, and can be inhibited by antibodies that neutralize the new crown virus.
The researchers also made it clear that their analysis showed that the evolutionary history of the new coronavirus was more complicated than expected, and that the RaTG13 virus found in China cannot now be considered the most recent ancestor of the new coronavirus.
The researchers believe that the genome of the new coronavirus may be the result of multiple recombinations of the coronavirus carried by different species of bats. Researchers speculate that the initial outbreak of the coronavirus may have occurred in an area near the Mekong River. The authors point out that horseshoe bats live in places such as Laos, Myanmar, Thailand and Vietnam.
The study once again provides strong evidence for the idea that the coronavirus carried by bats began to spread to humans after a spillover effect.
Column Editor-in-Chief: Zhang Wu Text Editor: Cheng Pei Caption Source: Visual China Photo Editor: Zhu Xuan
Source: Author: Science and Technology Daily