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Manipulating the genes of virus

  1. Apr 15, 2016 #1
    Genetic engineering can be very helpful in obtaining organisms with desired traits.If that is the case,Why can't we modify the genes of virus and make it more lovable organisms?.I mean what if they are manipulated in such a way that they don't need a host or even if they do,they should be useful to human body like how certain microbes such as lactobacillus,after entering our body,can help us in absorption of food and prevention of unwanted bowel movements.
     
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  3. Apr 16, 2016 #2

    Drakkith

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    That is exceptionally difficult to do. Viruses are extremely simple compared to a cell and therefore are much more limited in what they can do. They have little to no "machinery" like cells do and their entire purpose is to simply carry and pass on their genes in the simplest manner possible. Genetically engineering them to live outside of a host is essentially impossible for these reasons. You'd have to build an entirely different organism. Altering them to benefit the body is much easier, but the possibilities are still limited. Other than serving as a means to insert synthetic DNA into host cells, there just isn't much they can do.

    If anyone knows of other possibilities, feel free to post.

    Well, if you're having problems with the latter, we already have other options. :wink:
     
  4. Apr 16, 2016 #3

    jim mcnamara

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    This is a simplified answer:
    Generally, when a virus attacks a cell, it takes over the cells and 'makes' it create lots of virus particles inside the cell. The cell dies, lots of virus particles are freed to infect lots of other cells.

    Virus DNA can be modified using CRISPR technology. But if those modified viruses are put in a host and do their thing, you still wind up with more virus particles and dead cells. I do not get what this would accomplish. Maybe you could create safer vaccines this way.

    A positive variation that comes to mind: bacteriophages. These viruses attack species of bacteria.
    I do not know how practical it is to use 'specially DNA formulated' bacteriophages to kill off pathogenic bacteria in severely ill people, however.

    Another issue is the fact that viral DNA can become incorporated into the DNA of mammalian cells. Humans are mammals. So if we do use virus infections to cure another disease do we want some of that DNA to end up in our DNA? How often does this happen?
    I do not know.

    A decent article you can read without being an expert - note that it claims about 8% of human DNA originated from viruses and mostly it no longer functions; it is more like baggage:
    http://blogs.discovermagazine.com/loom/2012/02/14/mammals-made-by-viruses/#.VxJI7XriPIA
     
  5. Apr 16, 2016 #4
    You still dwelve around the technology that exists now and that cannot accomplish what I said.We can make a mouse glow at night by inserting in it a DNA of jelly fish.Our biotechnology can do that.But if that is possible,it should be possible to manipulate the gene of virus by inserting in it desired trait like that of lacto bacillus and make it self replicate within our body using DNA polymerase enzyme.So even if too many of them grow in our body since they are modified,they would not cause any damage to the body.In fact,human body has cells that are composed of 90 percent good bacteria.As long as the virus does not possess any harmful effect against us,it's presence in the body would be to some extent useful if we incorporate few desired traits such as helping our cells in replication,digestion etc....I'm talking about totally modifying the virus and make it ineffective and more lovable towards humans.:smile:
    If our biotechnology can do that,it would end the struggle between humans and virus and the deaths of millions of poors who are affected by something that they don't even know about.
     
  6. Apr 16, 2016 #5

    Ygggdrasil

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    Making a free living virus is probably a long ways off and it's not clear why one would start with a virus rather than a bacterium. We don't understand the genes that enable bacteria to be freely living, so creating a freely living virus is a long ways off. It would be possible to try to engineer commensal bacteria to perform beneficial tasks, and research in this area is ongoing. However, a big problem in this area is that the engineered beneficial bacteria (or viruses) usually are not as fit as the microbiota already present in the body, so they are likely to be outcompeted and disappear from the population.

    That said, there are a number of biomedical applications for engineered viruses. Viruses can be used for delivery of new genes into the body for gene therapy applications, and would likely be required for using technologies such as CRISPR to edit genes in adult humans. For example, viruses are used in CAR T-Cell therapies, in which doctors genetically rewire one's own immune cells to attack tumor cells.
     
  7. Apr 16, 2016 #6

    Drakkith

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    Of course he does. Future technology is unknown to us here in the present and cannot lead to a meaningful discussion precisely because we don't know what will be possible in the future. If you don't want to discuss current science and technology and its relation to the topic then I will have to lock this thread. An exception would be a discussion on cutting-edge technology that has yet to be brought into mass use or technology that we are confident we will have in the near future. But if you want to discuss those then we'd need specific examples, not a vague statement about what "should" be possible in the future with nothing to back it up.

    Note what I said in my first post about viruses not having the molecular machinery that cells have, such as ribosomes, mitochondria, etc. You would have to create an entirely new organism with the required machinery to do anything other than just replicate itself at the expense of the cell. The reason we can make a mouse fluoresce is because a mouse cell already has all the components required to produce the specific fluorescent protein. All it needed was the instructions on how to build it. It's like giving a car factory the instructions for producing a different hood to a car using the machinery they already possess. Doing the same thing for a virus would be like trying to make a call center produce car engines. You'd have to essentially build an entire factory from the ground up. Which would then no longer be a call center.

    I agree with Ygggdrasil in that modifying a bacterium for all of this would be much easier than a virus.

    While the latter fact is true, these bacteria are MUCH smaller than our own cells and mostly occupy our digestive tract and a few other spots as I understand it. So the human body's own cells still make up the overwhelming majority of our biomass. In addition, these bacteria do not replicate by infecting our own cells.

    Well, what does "Ineffective and more lovable" even mean? I'm looking for specific details here, not just a, "Well, they wouldn't hurt us" kind of answer. I mean specific traits, functions, roles, etc. Otherwise we're all just talking about some vague concept that isn't well defined.

    No it wouldn't. There's a difference between modifying a virus to be beneficial compared to modifying every virus everywhere to be beneficial, which essentially means that we've eradicated the original species. And that is an entirely different topic and a goal that is essentially impossible. The only human virus we've ever managed to eradicate is smallpox, due in large part to the fact that it has no natural non-human hosts.
     
  8. Apr 16, 2016 #7

    jim mcnamara

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    @Docsc
    Hmm. Can you provide a decent citation for this? If this has some merit I'd be interested to say the least.
     
  9. Apr 16, 2016 #8

    Ygggdrasil

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    This is a number a lot of people used to cite (you can get to it by a simple back of the envelope calculation), but just a few months ago a paper came out saying the number is closer to 1:1
    http://www.sciencedirect.com/science/article/pii/S0092867416000532
    See also:
    http://www.nature.com/news/scientis...s-have-more-bacteria-than-human-cells-1.19136
    http://biorxiv.org/content/early/2016/01/06/036103
     
  10. Apr 17, 2016 #9

    jim mcnamara

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    Thanks. I thought the OP meant something different - number of human cells with bacteria in them. For some reason I didn't think he meant gut bacteria.

    But. The Sender et al paper is also news to me. Glad to read it.
     
  11. Apr 17, 2016 #10

    Drakkith

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    Gah! That's a terrifying thought! :eek:
     
  12. Apr 17, 2016 #11

    Fervent Freyja

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