A combination of British and American variants?

All over the world constantly spread novel coronavirus variant virus strains, now scientists more found that 2 strains of different variants of novel coronavirus strains can also be further combined, recombination into a mixed virus!

Researchers at the Los Salamos National Laboratory in New Mexico discovered for the first time in a single sample the combination of the British strain B.1.1.7 and the California strain B.1.429.
She presented the research at a meeting of the New York Academy of Sciences in early February, noting that unlike common variants, which mutate one at a time, syncytiviruses can mutate multiple times at a time.

It is still unclear what impact this hybrid strain will have on the outbreak.
B.1.1.7 and B.1.429 are known to be easily transmissible and resistant, respectively. Cobb believes that the hybrid strains may have both characteristics, and fears that this could make the outbreak more severe.

The study also pointed out that the presence of the mutant combination means that some patients may have been infected with two different strains of the virus.

But David Pound, a biology researcher at Temple University in Pennsylvania who studies virus variants, says that novel coronavirus hybrids are common, and that there is no evidence of a large number of synthetized viruses.

At present, the syncyte virus has not been named.
It is understood that the syncytiovirus is produced when two strains of the virus infect the same cell and exchange genes when replicating. This kind of situation generally occurs under specific circumstances or coincidences, and the probability of occurrence is rare.

In most cases, the mutated hybrids produce a mutilated virus that can no longer be transmitted, but there are exceptions, said Dr. Furness, a professor of epidemiology at the University of Toronto.
How well the vaccine will work against the new hybrid is unclear, but he said: “It is a routine practice to adjust the vaccine, just as we have a different flu vaccine every year.”

‘We should be aware of the dangers of air travel if we know that densely populated environments tend to produce this strain,’ Furness said.

Sly, a professor emeritus at Wyson University’s School of Occupational and Public Health, notes that this may be the first reorganization, and it may not be the last.
“The more viruses there are in the world, the more mutations there are in the mix, and the more likely it is that you will produce a brew that is extremely dangerous,” he said.

The mutation found in this study is a Genetic recombination of the following types of virus mutations.

Virus Variation Popular Science (from Baidu Baike)

Viruses are prone to mutating.
Its genetic code or genome is mainly concentrated in the nucleic acid chain, as long as this nucleic acid chain changes will affect the characteristics of their offspring.
In fact, viral genomes are not static as they proliferate, but mutate automatically from moment to moment.

mutation

A virus Mutation is a chemical change in the sequence of nucleic acid bases in the genome, which can be a single nucleotide change, or the deletion or translocation of hundreds or thousands of nucleotides.
A variety of physical and chemical Mutagens can improve the mutation rate, such as temperature, radiation, 5-bromouracil, nitrite and other effects can induce mutation.
The mutant is different from the original wild-type virus, showing changes in virulence, antigen composition, temperature and host range.

Virulence changes have strong and weak strains, the latter can be made into weak live virus vaccine, such as spinal fluid polio vaccine, measles vaccine, etc.

Conditional lethal mutant refers to a virus that can grow under certain conditions after mutation, but can not reproduce under the original conditions and is killed.
Among them, the most important was temperature-sensitive conditional lethalmutant (TS strain), which could proliferate when incubated at a specific Temperature (28-35 ℃), but could not proliferate when incubated at a non-specific Temperature (37-40 ℃), while the wild type could proliferate at both temperatures.
This is apparently because the protein encoded by the mutant gene lacks its proper function at unspecified temperatures.
Therefore, most TS strains are also attenuated strains.
The TS strain has been isolated from many animal viruses, and the strains with good genetic stability have been selected for the preparation of live alkali vaccines, such as influenza virus and the TS strain of spondylitis virus.

The host adaptive burst strain, such as the mutant strain of rabies virus, ADAPTS to proliferate in the rabbit brain and changes from “street virus” to “fixed virus”, which can be used as rabies vaccine.

Genetic recombination

When two related viruses infect the same host cell, their Genetic material is exchanged, resulting in heritable progeny that are different from their parents. This is called Genetic recombination.

Recombinations between live viruses, such as those between two subtypes of influenza virus, may result in genetic recombination to produce a new hybrid strain with one parent of hemagglutinin and the other parent of neuraminidase.
This is of great significance in exploring the principle of natural virus mutation.
Influenza causes a pandemic every decade or so, probably due to genetic recombination between human influenza viruses and influenza viruses in certain animals (chicken, horse, pig).

For example, when two strains of the same virus are inactivated by ultraviolet light, if they are cultured together, the inactivated virus can often be revived to produce infectious virions. This is called Multiplicity reactivation. This is because the damaged gene sites on the nucleic acids of the two viruses are different, and the reactivation is due to the mutual complement of the two viruses.
So now it is not necessary to inactivate the virus with ultraviolet light to make a vaccine, in case the virus comes back to life.

For example, a vaccine strain of influenza A virus (A0 or A1 subtype) that can grow well in chicken embryos is inactivated by ultraviolet light and then cultured together with live Asian influenza A virus (A2 subtype) to produce influenza A2 subtype virus with the former characteristics, which can be used for vaccine production. This is called Cross reactivation.

Leave a Reply

Your email address will not be published.