
For Safer Food, Just Add Viruses - thaddeusmt
http://www.pbs.org/wgbh/nova/next/nature/phages-for-food-safety/
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lifeformed
Viruses seem so weird to me. They're naturally emergent nanobots.

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derefr
I wouldn't really call them nanobots; they don't _function_ in any active
manner. They're really just like their digital counterparts--malicious
_program data_ that gets executed by our cellular machinery.

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Peaker
They are not pure code. They come with a protein coat and a bunch of
proteins/enzymes to bring the code to the cell or nucleus, and sometimes more
functions.

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derefr
Sure, but those are produced by the cell at the behest of the viral code; not
produced by the virus. The freshly-minted copy of the virus doesn't get to
_react to stimuli_ by producing proteins once it has left its host cell. It's
a lot more like the relationship between, say, pollen spores and the
gametophytes they contain.

To put it another way--a post-code and stamp on an envelope will get the
postal system to deliver its contents to the right destination. That doesn't
mean the contents are functioning to deliver themselves there; they're relying
on a working mail-transport system that wants to take them there.

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manmal
Given that the human digestive tract (reportedly) contains more bacteria than
the human body has cells, and they are vital to our survival, how can spraying
bacteria-killers on food not be harmful?

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Ravengenocide
According to this link:
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3278644/](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3278644/)
phages target specific pathogenic bacteria, and "[...]phages only minimally
impact non-target bacteria or body tissues". So that would mean that even
though they target bacteria, they would only target a specific bacteria and
not all.

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Amadou
You do have to wonder if they aren't over-stating the specificity. The older I
get, the more I come to expect the unstated "but..." on claims like that. As
the saying goes, "When it's too good to be true, it probably is."

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bhickey
I don't think they're overstating this claim. It's a double-edged sword.

If you have an infection your doctor can give you antibiotics and send you
home. Antibiotics tend to be wide spectrum and kill entire classes of
bacteria, like gram-positive, indiscriminately.

A phage that kills one strain of E.coli might be completely incapable of
infecting a closely related E.coli strain. Thinking that a single phage could
be effective against closely relate pathogens, for example E.coli AND
Salmonella, is wishful thinking. This might have the upside of preserving gut
flora, but it's easy to see how it would confound treatment: some things are
very difficult to grow in vitro.

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Amadou
_Elanco, sells a liquid phage product called Finalyse that is sprayed on the
hides of cattle before they’re slaughtered._

I'm thinking that name is just a little too on the button.

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brianbreslin
This was fascinating. Could phages be engineered to attack mrsa and other
superbugs we see in hospitals?

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bhickey
It depends.

There are extant phage that predate staph, like Phage K. There are some
hurdles you'd need to overcome. Foremost among these is when compared to
antibiotics, phage suck for treating disease. This is a big part of the reason
everyone beat a path to antibiotics

Phage are extremely narrow spectrum. You can select for a high-fitness phage
with serial passages: Plate the host bacterium along with some phage. Find the
largest region of dead host (a plaque), pick it and repeat for several hundred
generations. The good news is that you'll have a high-fitness phage. The bad
news is that it will probably only infect the particular strain of bacteria
you've been using to select it. I worked with a fitness optimized E.coli phage
that wild-type E.coli probably would have laughed off. I haven't read the
therapeutic phage literature, but my assumption would be that you may need to
optimize

Phage have some issues with immune clearance. The immune system really loves
to eliminate foreign looking viruses. The concentration of phage injected
intramusucularly falls very fast. Again, this might be something you can
overcome with serial passages. There was some work in rabbits where the
authors found an enrichment for mutations in the capsid (the phage's head). I
don't recall if they quantified the fitness impact of these mutations.

If I ever get out of software development, it'll probably be to work on phage.

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neaanopri
This could be a replacement for antibiotics once they become completely
ineffective

