viruses

:) .. What a splendid question.

Technically, there's really no particular reason why there shouldn't be something along such lines. Weather they exist or not, that's another matter.

As you no doubt already know, viruses attack cells because the cell structure has all the means within it, once hi-jacked and compelled to do so, to mass produced the receptacles the virus's replicated genetic material will pop itself into and go off on its way, each to intern infect another living cell.

I suppose there's no biological reason why a virus shouldn't evolve with the capacity to jack another virus in transit and insert it's genetic material in preference to the originals - but as far as viruses in general are concerned a cell makes a far larger, appealing and easier target.

The coating on a virus is pretty tough stuff. Compared to a cell wall it's like drilling through quarts.

Equally, the capacity for one type of virus to successfully target another, problematic. But, as I say, on paper... ;)

 
Thanks, because i was reading an article somewhere (forget which magazine) that said we all could have evolved from viruses. But unless theres viruses that infect other viruses i dont see how that would have been possible.
 
Well, in saying such a thing in the first place what you wouldn't have had would have been a Virus in the, Virus sense of the world - unless it possibly is and means that some form of virus introduced genetic characteristics into some other cellular form of life which may possibly have given rise to characteristics we associate with single celled organisms as we more commonly view them today.

Conceivable. We generally associate Virus's with disease because these, as far as we remain aware, present such pathology. However, it's not especially inconceivable to imagine a form of virus more benign, possibly parasitic in nature. If not existing today, perhaps at some distant point in the past.

Rather than destroying the host cell, perhaps working in co-operation with it -more like a proto-sperm and egg sort of an arrangement than pathogen...

As I say, on paper.... etc, etc.
 
It wouldn't really make much sense for a virus to target another virus. A virus hijacks a cell's metabolic pathways to reproduce itself. These don't exist in viruses to be exploited so not much would happen.
 
Well, no. Indeed. All it would accomplish is one virus substituting it's genetic material for that of another virus - the said virus carrying on and behaving exactly like... well. The same virus it attacked really.

Perhaps one could explain such a mechanism in terns of a strain of virus evolving to maintain its own genetic integrity - y'know, rather than altering its genetic code so as it can generate new strategies to overcome autoimmune response our hugely Nazi Virus here perhaps might elect to allow other, more inferior strains to do that for them and high jack the results...

The advantage being, this Predatory Virus itself would never be attacked by the body. Being, as far as the immune system was concerned, it wouldn't be the virus attacking it the immune system would leave it alone. Disguising itself as a lamb by wearing the skin of a wolf, if you will.

But true. Probably only works on paper.... ;)
 
injus5 said:
Are there any viruses that attack and replicate using other viruses?
Click to expand...
No. Viruses have no reproductive capabilities and this is why they need to invade a host cell - not another virus - to replicate. Do your research on what a virus is.

There are some theories that suggest that an ancient virus may have given rise to the eukaryotic nucleus through a symbiotic relationship, but this is a completing different matter and is based on speculation. The basis of this theory involves the sharing of such features as linear chromosomes, mRNA capping and a separation of transcription from translation with eukaryotes. It has been proposed that the eukaryotic cell nucleus was derived from a virus and that the nuclear envelope is a remnant of the viral envelope, but I find this very difficult to believe.

Likewise, the notion that viruses could team up with other viruses to replicate is pure fantasy with no basis in biology. Nothing from nothing equals nothing. They have to team up with a host cell that can replicate.
 
Well, I wouldn't think that such a thing exists..thought it would be interesting if it did...hmm..Anyhoo.

A virus is a nonliving entity that does not gain "living" status until it is within the enriching confines of a host cell. There, and as invert_nexus mentioned, it takes on the control of that cell's machinery to sustain its self-replication. For that reason, I also agree with invert_nexus that there would be no point in it taking over another virus, since there are no means of replication.

Secondly, a virus, when you get down to its core, is really nothing but DNA or RNA and 2 reverse transcriptase enzymes (in the case of a DNA virus). Meaning that there isn't really anything to interfere with. Yes, one may argue the point that one virus's DNA may atatck another's and alter it, but for that to happen...you still need the enzyme DNA polymerase...which is not found, based on to date scientific data, extra-celluraly (i mite have to double check my sources, but its as far as I know, plz correct me if I'm wrong :D ). Also, DNA is a pretty hearty molecule, so its going to take some high optimums to undo its structure (i.e PCR temps of 72-96'C). So, something within the human body, extra cellularly, could not promote that. Even if this were to be carried out on a petri dish, it would no longer be Virus-Virus interactions, simply DNA transformation; which means the addition of new genes to an existing template of DNA.

Yes, I know a phage is a vector (means of transporting genetic material) and such a reaction would still be Virus-Virus, but what makes it a regular transformation reaction is that it does not occur spontaneously; which is exactly what happens when a virus invades a host cell.

Finally, I wanted to say that a virus is a parasite, meaning that it would be impossible for it to survive and reproduce without the aid of a host, so a parasite attacking a parasite is just a double-negative if you get my drift ;).

Regarding the symbiosis theory, I find it interesting, but it still has many flaws to be worked out when it comes to virsus. For example, a virus working symbiotically with another cell is, yet again, transformation for that cell's benefit. In this case, a virus wouldn't be the evil disease causing agent we know today, but rather a simple vector to transport DNA that mutates a prehistoric cell for the better. In this case, it wouldn't be symbiosis becuase the virus is not alive; it ceases to exist once its incoportated into the host's DNA since it never resurfaces again...mebbe polymorphisms? So, I also agree with Valich's point.

I hope this cleared sum stuff up. Sorry if my language sucks, i try :).
 
There is theory that a virus is not just a host and that it has contributed to the origin of life. A hyperthermophile virus called PAV1 has been discovered in hydrothermal vents related to the genome in certain eukarypote hypertherthermophile chemolithoautrophics. Further conjecture is greatly cautioned.

See: Geslin C, Le Romancer M, Erauso G, Gaillard M, Perrot G, Prieur D (2003) PAV1, the first virus-like particle isolated from a hyperthermophilic euryarchaeote, Pyrococcus abyssi. J Bacteriol 185: 3888–3894
 
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