What we should know about Viruses

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Written by

rbee

What Covid 19 made me do 🤫

3 years ago

Topics: Science

Virus isn't just super small, there is omething behind it.

The coolest thing about virus is that they are simple. Their whole essence can roughly be divided into two parts.

One of them is the protein shell, which protects the virus from the environment and helps infect cells, which is called a capsid. Also, some viruses have got a supercaspid – an additional layer of protection made of lipid, protein or carbohydrate structures. Inside the capsid is a set of genes that stores information about the life activity of the virus. This is genome. All important instructions kept in here: how to propagate the genome, how to regulate and start the process of cell infection, how to build capsids for new viruses.

Long story short, a virus is like an eternal wanderer.

It is always ready to pack. It carries only the essential things that will help it break into someone else’s house, settle in and start dividing.

Viruses are extremely diverse in nature.

You know that your hereditary information is recorded in double-stranded DNA, but such monotony is boring for viruses. Their information can be encoded in single-stranded and double stranded DNA, and even in RNA.

In 1971, David Baltimore created a classification where he ordered viruses according to the type of their genome. There were seven such classes in total.

And for example, the well-known Human Immunodeficiency Virus, also known as HIV, which, according to official data, infected about 38 million people around the world, belongs to Baltimore’s 6th class these viruses have got a single-stranded RNA that is located inside of their capsid.

Look carefully, which part of this typology you might recognize?

SarsCoV2 – a family of those same viruses that stopped the planet in 2020. And there is another your old buddy and a buddy of all your snotty friends. The 4th class includes rhinoviruses that can cause nasopharyngitis, or … in other words, the common cold. You can give it a piece of your mind for your fever, runny nose, and sore throat. But in fact, not only rhinoviruses are responsible for such symptoms.

According to various estimates, they are responsible for 30-50% of the cases. Adenoviruses, Orthomyxoviruses, whose typical representative is the Influenza virus, and others, even bacteria, may be the cause.

Therefore, due to the wide variety of those responsible for our snot, it’s impossible to create one universal pill or cold vaccine so that you never get sick.

For example, even the flu virus is too common a name, and to talk about a certain type of the virus, you need to specify its strains.

For example, the H1N1 influenza strain is a subspecies of the influenza A virus, which is part of a genus of the same name, which is part of the Orthomyxovirus family, which is part of the Articulavirales order, class insthoviricetes.

And, as you can see, each step up increases the amount of the types of the viruses by dozen, if not hundreds of times so, there is no universal vaccine for “all the bad things” and there cannot be one.

The next curious thing is that all these troubles in the form of cancer, AIDS, hepatitis are caused by viruses that are merely 20-400 nanometers in size. A tip of the needle can accommodate tens of thousands of different such samples. Forget the needle; 10 viruses can fit in one bacterium. The size, indeed, does not matter in this case.

There are viruses that only infect bacteria. They are called Bacteriophages. Translated from Greek, it means “devouring bacteria”. Only in fact, they do not devour anything.

https://www.google.com/search?q=Caudovirales&prmd=ivsn&sxsrf=ALeKk02Y0tIZqTz2jPjHVuCSzi_zAV6CsA:1620557816920&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiAtI-ouLzwAhWIzpQKHT_9CVMQ_AUoAXoECAIQAQ&biw=412&bih=728&dpr=2.63#imgrc=siMrphovhfwHVM

On the picture above, you can see a representative of the order Caudovirales or tailed viruses. It resembles a molecular syringe. When a virus binds to a bacterium, it literally injects it genome, double-stranded DNA, into the cell, and leaves its protein coat outside.

The instructions of the bacteriophage become mixed with the instructions of the infected cell, and its usual life activity ceases. The cell begins to use its resources to produce new genomes and proteins of the virus; this stage is called replication. The cell wears and tears, spending all its resources to produce as many viruses as possible. The final stage – lysis – is approaching.

New viruses fill the entire space, the host cell breaks and a new portion of the virus enters the environment. But cell lysis may not occur immediately. A cell can trigger its division, which doubles the virus as well. In such cases, the viral genome is called a provirus, or, in case of bacteriophages, prophages.

All this acts like a time bomb that might trigger the activation of viruses in host cells at some point.

HIV doesn’t break the cell at all. The initial stages are the same: attachment, infection, reproduction of viruses. But lysis of the cell does not occur, and the produced viruses simply bud off from their creator and step on an evil path while the infected cell continues to produce new samples.

It is amazing that during all these infections, there is real chaos taking place in the gene world.

Viruses integrate their genome into a host cell. That is their nature. And this can lead to a variety of consequences. The virus can embed itself quietly and remain inactive for a long time.

In addition to the usual infection. It can mutate and acquire characteristics useful for survival. And, suddenly, those useful traits can be borrowed from viruses by other organisms. Just as bacteria can grow stronger because of the virus, so can viruses.

This rule applies to people as well.

Humans has been living on Earth for a long time. Not as long as viruses, of course, but we simply could not have dodged rendezvous with little buggers. And traces of those cases are settled in our genes.

The viral sequence of retroviruses make up 8% of human DNA. It is believed that these are sleeping genes which in rare cases, and wake up and cause cancer. But sometimes, it is not the mafia that wakes up, but the police.

Relatively recently, it turned out that many viral proteins from an ancient virus can be found in the cells of a 3-day-old embryo. Viral protein raise the level of another protein, whose task is to sit on the surface of the cell and prevent other viral infections from entering it. It turned out that the “resident” virus protected embryo’s cell from its own kind.

Real life takes place at the microscopic level, but … can we call a virus a living thing?

According to the canonical definition, a virus is an infectious agent, typically consisting of a nucleic acid molecule dressed in a protein coat. And there are three kingdoms of living organisms: archaea, eukaryote, and even bacteria. And there is no viruses listed under those three kingdoms.

Behind the question of what a virus is, there is a larger one – what is life itself?

Life is:

- Independent conversion of substances into new genes and protein

- The ability to grow

- The ability to excrete decay products

- Multiplication by division

In 1967, the microbiologist Andre Lwoff stated that a living organism is made up of cells. But a virus doesn’t have cells.

So in 2000, the International Commission on the Taxonomy of Viruses announce that “viruses are not living organisms.”

Micahael Cordingley, a virologist and author of Viruses: agents of the evolutionary invention, puts forward an even more interesting wording: “They are egotistical, independently evolving infectious information”.

So, in this case, we no longer need to define a living or non-living organism.

Viruses are simply pure information, the purpose of which is to use the resources of someone else’s system to increase the amount of initial information. It is a little unusual for our nervous system that there is information in the world that affect people’s lives.

We are used to the fact that a stone is not alive, but a dog is. And then they tell you that somewhere on the nanoscale there is roaming information that can affect you, a massive human being…

And if you try to place the viruses on the map of the kingdoms of living organisms, it will look creepy but extremely exciting coolest thing about virus is that they are simple. Their whole essence can roughlu be divided into two parts.

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