Where are all the good Viruses?

[dolphinboy]

I’ve been trying to find out about beneficial viruses. Everyone knows there are bacteria that are beneficial to humans and how important they are to our overall digestion and immune systems, but there seems to be very little press on viruses that also do us good.

Here’s one article I found that talks about them in general terms.

So if there are beneficial viruses, and apparently there are, why don’t we hear more about them? Is it because they are few and far between? Is it because their nasty cousins get all the press, or is it because bacteria have better public relations?

I don’t believe viruses are inherently evil any more than I believe bacteria are inherently good. So what’s the straight dope on beneficial viruses?

[Mikeisskeptical]

Unlike bacteria, viruses aren’t really living things, they’re basically just strands of RNA with a protein casing and a delivery mechanism like a syringe. They inject RNA into your cells, which your own cellular machinery reads out and starts making copies of the virus. These eventually burst out, destroying the cell. It tends to be a bad thing.

EDIT; Sorry, they can be RNA or DNA based.

[Chronos]

A bad thing in the short run, maybe, but a lot of evolution is enabled by viruses. And I’m not talking about just evolving to be better at beating viruses: A lot of our genetic material originally came from viruses.

[Mikeisskeptical]

@Chronos

A bad thing in the short run, maybe, but a lot of evolution is enabled by viruses. And I’m not talking about just evolving to be better at beating viruses: A lot of our genetic material originally came from viruses.

Yes, and I believe it’s common for bacteria to acquire new, useful genes by the process of viruses “cutting” them from another bacteria and “pasting” them into the new hosts genome. Isn’t that pretty much the basis of how CRISPR works?

[DSeid]

@dolphinboy

I’ve been trying to find out about beneficial viruses. Everyone knows there are bacteria that are beneficial to humans and how important they are to our overall digestion and immune systems, but there seems to be very little press on viruses that also do us good.

Here’s one article I found that talks about them in general terms.

So if there are beneficial viruses, and apparently there are, why don’t we hear more about them? Is it because they are few and far between? Is it because their nasty cousins get all the press, or is it because bacteria have better public relations?

I don’t believe viruses are inherently evil any more than I believe bacteria are inherently good. So what’s the straight dope on beneficial viruses?

Mainly that these “friendly” viruses are harder to identify but clearly there. Really just starting to be studied.

@Nature 2010

… Gordon’s group and others are beginning to catalogue the human ‘microbiome’, all the microorganisms living in the human body, using advanced DNA sequencing technologies. Until now, however, such attention has primarily focused on the bacteria rather than viruses.

“This is a wonderful study,” says David Relman, a microbiologist at Stanford University in California, who is involved with the US National Institute of Health’s Human Microbiome Project. “It could be that viruses are the real drivers of the system because of their ability to modify the bacteria that then modify the human host,” he says. “So this study is in some ways looking into the genesis of the human body by seeing what viruses within it are up to.”

Microbial truce

According to the new study, bacterial viruses in the terminal gut or colon seem to exist in a more stable state than do similar communities in the environment, such as in the oceans. Faeces from each individual — four pairs of identical twins and their mothers — carried a distinct viral community that varied by less than 5% over the course of a year. The bacterial viruses also appeared to mainly be lying low as ‘prophages’ rather than multiplying and killing the bacteria they infect. …

More…

@NPR 2016

… These particular viruses are called bacteriophages. And, until recently, many scientists had sort of ignored the ones in the gut, says Mark Young, a virologist at Montana State University. Researchers didn’t have good tools to study these phages, Young says, and understanding them hasn’t been a priority, because they don’t seem to cause problems.

“Most virologists are looking at how viruses cause disease,” he explains. “We’re flipping that around, and looking at the possible role for viruses in promoting health.”

To begin their study, he and his team sequenced the genes of bacteriophages found in the guts of two people. They combined their data with evidence from a previous study, which had sequenced bacteriophages in more than 160 people from the U.S. and the U.K.

In the larger data set, about a third of the people had healthy guts. The others had a chronic intestinal illness — either Crohn’s disease or ulcerative colitis.

From the combined group of people, Young and his team identified 23 bacteriophages that seemed to be associated with a healthy gut. These viruses were common in more than half the healthy people and were much less common in people with Crohn’s or colitis, the team reports this week in the Proceedings of the National Academy of Sciences.

“We speculate — and clearly at this point, it is speculation — that these viruses help maintain your health,” Young says.

Their conclusion is still speculative, he explains, because he and his team can’t tell from their work whether the bacteriophages are contributing to a healthy gut or are just a result of that health. …

Also some are finding the DNA of us that comes from viruses. 8% of our DNA apparently. Figuring out what it does though …?

You are up to 8% virus, at least as far as your genome is concerned. Up to 100,000 pieces of ancient viral DNA live among our genes, yet their function—if any—has long been unclear. A new study suggests that some of this foreign genetic material may boost our immune systems, even protecting us from other viruses.

When a type of virus known as a retrovirus infects a cell, it converts its RNA into DNA, which can then become part of a human chromosome. Once in a while, retroviruses infect sperm and egg cells and become “endogenous,” meaning they are passed down from generation to generation. Endogenous retroviruses, or ERVs, are not able to produce new viruses, and because of that scientists originally assumed that they were harmless genetic fossils.

Controversial studies have long suggested that certain cancers—like some lymphomas—result when ERVs interfere with normal gene function. But more recently, researchers have raised the possibility that these viruses can also be a good thing. ERVs—perhaps inherited millions of years ago—may affect genes important to placenta function and thus may improve our ability to carry a pregnancy. What’s more, there is evidence that they play a role in the early human embryo, where they may help fight off infectious viruses. …

[dolphinboy]

Good stuff. Thanks DSeid. MSU is just a few miles down the road from me. I should have just started there.

[dtilque]

@Mikeisskeptical

Yes, and I believe it’s common for bacteria to acquire new, useful genes by the process of viruses “cutting” them from another bacteria and “pasting” them into the new hosts genome. Isn’t that pretty much the basis of how CRISPR works?

No, CRISPR is part of bacteria’s defence against viruses. You may be thinking of plasmids

[Isilder]

The virus in the genome are inactive … How about look at active viruses.
I guess innoculating benign virus, like cow pox to small pox, or benign HPV (warts) to cancer causing (eg cervical and oral cancers) HPV , are “good” ? Questionably good. Fortuitous I guess but only because they protect from worse.
It may be that there are good viruses active in your body, but their “goodness” would be to kill bad bacteria ?

[Mikeisskeptical]

@dtilque

No, CRISPR is part of bacteria’s defence against viruses. You may be thinking of plasmids

Ignorance fought.

[Anaglyph]

@Isilder

The virus in the genome are inactive … How about look at active viruses.
I guess innoculating benign virus, like cow pox to small pox, or benign HPV (warts) to cancer causing (eg cervical and oral cancers) HPV , are “good” ? Questionably good. Fortuitous I guess but only because they protect from worse.
It may be that there are good viruses active in your body, but their “goodness” would be to kill bad bacteria ?

Phage therapy uses bacteriophages (viruses that infect bacteria) to treat bacterial infections. However, in contrast to antibiotics, there are no “broad band” bacteriophages - you need a very specific phage to kill a particular strain of bacteria.