Viruses Infected By Viruses

SpaceAdmiral writes "Scientists have discovered a virus that can infect another virus. The fact that viruses can essentially get sick may change the debate over whether they are alive or not. Check out Nature for a slightly more technical article about the 'virophage.'"

Re:reproduction

[LiquidHAL]

I'm pretty sure they can reproduce, else there would be no risk of spreading them and they'd all die out soon after coming into being.

Re:cancer

[linuxbert]

in fact Viruses have been linked to cancer. Human Pamplona Virus (HPV) is thought to be solely responsible for cases of cervical cancer. Hence the push to get them all vaccinated at a young age before they start having sex.

Re:reproduction

[ShadowRangerRIT]

The reason your school taught you that is because the definition of living usually taught in schools includes such characteristics as:

1. Metabolic function
2. Physical Growth
3. Independent reproduction

just to name a few. Viruses don't possess any metabolic function (they use the host cells hijacked machinery), they don't grow (once created, they are essentially static objects until they bump into a cell), and they have no means of independent reproduction (again, the hijacked cells reproduce the virus).

On the other hand, many people simplify the definition of life to solely the ability to reproduce (independently or not), which makes viruses alive, but also makes prions alive, and makes it fairly easy for humans to "create life" in the form of self-reproducing machines.

Re:That's not about computer viruses!

[Jimbob The Mighty]

Since previous /. story was about the university malware professor, for a second I thought this story was talking about computer viruses infecting computer viruses. Would that be possible too?

Sure, there are plenty of software virii that can infect machines running Microsoft Windows...

Re:Software Viri too?

[SpottedKuh]

So are software viruses alive too?

Obligatory link to an old paper: Eugene H. Spafford. Computer viruses as artificial life [carleton.ca]. Artificial Life, 1(3):249-265, 1994.

The short answer is "no," but it makes for an interesting read if you have some whiskey to drink while you're reading it.

Re:cancer

[wizardforce]

HTLV-1 causes changes in gene expression resulting in adult t-cell leukemia. This year my advisor had a paper on this very research detailing some of the changes which are involved: http://www.jbc.org/cgi/content/abstract/277/51/49459 [jbc.org] basically the idea is that the virus in its attempt to replicate its self using cellular machinery alters the expression of specific genes, Tax, CREB and histones. better explained from my advisor: "HTLV-I Tax functions to short circuit the normal regulation of cell cycle progression by abrogating the need for mitogen stimulation and blocking checkpoint controls, resulting in unregulated initiation of S phase." in other words, the virus kicks out some of the cell regulatory controls that at least in part prevent it from becoming a cancer cell.

How does this makes a virus living?

[Regeneratenl]

according to the definition of life [wikipedia.org] 'getting infected by a virus' doesn't make you a living organism...

Re:cancer

[Mal-2]

Human Pamplona Virus (HPV) is thought to be solely responsible for cases of cervical cancer.

I believe you meant papilloma [wikipedia.org] (a virus that induces warts and similar growths), not Pamplona [wikipedia.org] (a town where you can be an idiot and get yourself gored by a bull).

Mal-2

summary = wrong

[fatduck]

Summary is totally misleading. The story isn't about viruses "getting sick" - it's about a certain type of satellite virus (not new) that can only infect a host that is already infected by another virus. Essentially the satellite virus is competing with the original virus for metabolites. The discovery here is that for the first time a satellite virus is competing for these resources to such an extent that it is actually destroying the original virus.

Re:reproduction

[PresidentEnder]

Yes. Mules cannot reproduce. The distinctions between species are based on the production of offspring which can reproduce to the nth generation.

Re:here we go again

[moteyalpha]

I found an open source project called 'littleb' which can be researched at littleb.org that may provide a common framework to analyze and understand these aspects of systems. If a good functional model can be made then it is easier to see how changes and evolving situations might proceed. Not enough tools exist as yet to define the points of action between molecular systems. It is certainly approaching this point and I always enjoy new topics and - converging search through noisy space - sounds like fun. Secondary electron interaction in systems which were considered to only interact with valence electrons is an interesting new area also.

Re:reproduction

[xeoron]

Am I the only one that thinks that they replicate by way of using the the host tissue cells by tricking it to make duplicates?

Re:reproduction

[ShadowRangerRIT]

Just to be clear, what I listed was only a subset of the definition. If you want a more formal definition, there is a decent one here: http://en.wikipedia.org/wiki/Life#Definitions [wikipedia.org]

Fire for instance, fails on homeostasis (no regulation of state to maintain equilibrium), organization (no cell structure; while I don't think we should require cellular structure, you do need some organizational principle), and no adaptation.

offtopic

[Anonymous Coward]

If A = B why call it B?

Because the statement that A = A is tautological, but the statement that A = B is not. The truth of the former conveys no information, but the truth of the latter does. To put it like Frege puts it, "The morning star is the morning star" is a trivial statement, but "The morning star is an evening star" is an astronomical discovery [wikipedia.org].

Re:Software Viri too?

[ne0n]

Whiskey [wikipedia.org] is the crap left over when all the whisky [wikipedia.org] is gone.

No more Laphroaig? Powers'll do ya.

Re:summary = wrong

[Anonymous Coward]

you're still misleading, albeit slightly. One virus, called Sputnik, infects cells that contain another virus, called a mimivirus. Sputnik can only survive (ie replicate etc) in the presence of that mimivirus. The study shows that sputnik only appears in those regions where the mimivirus is being made. The presence of sputnik in those regions negatively affects the viability of the mimivirus. Therefore, the authors conclude, sputnik is a parasite of the mimivirus.

That is the main thrust of the story.

A vague notion like "competing for metabolites" does not say very much, nor is Sputnik - as you claim - a satellite virus. Sure, it has some similarities, but significantly, sat. viruses do not kill their associated viruses, in fact they often help them. also, satellite viruses encode for only one or two proteins, whereas sputnik encodes a lot more proteins....

Re:reproduction

[arotenbe]

Great-great-grandparent post.

Re:reproduction

[Serious Callers Only]

See Ring species [wikipedia.org] - species boundaries are not as clear cut as your definition would have them, though that's a good rule of thumb.

There are many arguments over how to define species - Morphological differences (which in practice is often the starting point), Biological differences, Shared ancestry etc.

Re:there's no easy answer

[tpjunkie]

Actually, mitochondria do replicate within the cell, contain their own genetic material and ribosomes and even contain the genes for a full set of their own tRNA molecules. They simply do not have enough genetic information to survive on their own, outside of a cell. I would argue that they are conditionally alive; they replicate on their own and can perform respiratory functions (albeit requiring the usage of host cell proteins) yet cannot "live" on their own apart from a cellular host.

Re:reproduction

[x2A]

virii

Viruses. Virii would imply the latin word, which described a liquid like substance. As we know, liquid has quantity, not quantities, therefore is not pluralised (eg, four pints of water, or four water pints. We see the quantity is pluralised, not the substance).

Understanding what viruses actually are came a long time after latin became a dead language, and so the pluralisation occured in our modern languages, while the pluralisation in latin continues to make no sense.

Re:cancer

[LunaticTippy]

Cervical cancer kills nearly 4000 US women a year. This could be reduced drastically by vaccination. Vaccination also provides other benefits, such as not becoming infected with genital warts.

I think it is sad how obsessed with the illusion of safety we are becoming, but this one is pretty reasonable.

Re:reproduction

[evolvearth]

Don't all 'higher' animals begin life essentially as a parasite within the mother? Now granted, its the same species in this scenario, but it's still something to think about.

A living individual animal only lasts for X amount of years. The level of importance is down to the gene, not really at the individual, but the individual will try to spread as much of its genes as it can to the next generation. This is a lot harder to do with females than with males, because females are typically stuck with the job of raising the kid, costing both resources and energy.

The fetus under development is not a parasite, because the benefit of the host is to pass on its genes to yet another generation.

What about fungi? They are considered organisms and alive, yet they grow as a parasite in or on a living host or other form of organic matter, and cannot grow or reproduce without said host. That's not too far off from how a virus reproduces. True, fungal reproduction does begin within the cells of the fungus itself, but the line really isn't as clear as many would think.

We all need some kind of resources to survive, but we have replicating machinery that viruses do not. Fungi have this replicating machinery, and much of what is understood about the replication machinery in eukaryotes comes from the S. cerevisiae, a fungi. It doesn't matter if an organisms is living on a host to leech off of some of the host's resources such as nutrients. We all get our nutrients externally. Viruses can't even replicate without hijacking the machinery of another organism. That's really neat, but that doesn't quite make them alive.

On that note, no life form truly reproduces autonomously; the chemicals that life is formed of are created/encoded from outside materials. Animals take in these outside materials by eating, plants draw them from the ground, fungi from the aforementioned host/organic matter.

That said, It is true that when viruses replicate, the 'parent' virus does not take in material to reproduce (and rather, as mentioned, hijacks the host cells systems to do so). As important as that distinction may sound, I believe that when compared to how 'true' life forms reproduce, it seems mainly a question of semantics. It's a tough call, I guess all that can be said is that viruses certainly define the term 'gray area...'

It's not really an issue of semantics if you consider how important it is for an organism to be able to replicate itself. It's one of the basic things of being alive, probably the most basic.

Re:cancer

[ceoyoyo]

True, but those are viruses that infect humans. The point of this virus is that it infects another virus. Actually, when you read the article, it doesn't so much infect the mother virus as hijack the mama virus's hijacked replication machinery, which was originally co-opted from the host cell.