Re: Pathogenic Mosquito Sanitizer?

[Mega]

Hey, that's a great idea...


What I read so far:
It has been tried the following: Genetically engineerred to be infertile males were released into the wilderness. They mated with the female mosquitos and those lay eggs. But the 'children' generation died in the larvae state.

The mosquito population was reduced to 20 % (upt to 80% were killed!)


Mosquitoes are annoying, so why not make the human-blood-sucking of them get extinct instead?? (Animal blood OK)
 

Am Samstag, 2. Juni 2012 10:12:24 UTC+2 schrieb Margret Storm:

Would it be possible to engineer a contagious bacterial strain that resided in the digestive tracts of mosquitoes, and had little effect other than releasing antimicrobial enzymes into the pharynx and salivary glands? Hopefully, this would prevent the spread of mosquito-borne diseases like malaria, as well as help prevent secondary infection of bites.

Forgive me in advance for any ignorance - the idea has been bugging me (hah), and I really want to know.

[Andreas Sturm]

I remember having read something that some species really prefer human sudoral. In it there is a protein which attracts those beasts. I also believe to remember that some scientists knocked-out the receptor for that protein in mosquitoes thus they were much less annoying to humans.

2012/6/3 Margret Storm <i.am....@gmail.com>

Whoop, somehow missed the last bit of your post in parentheses :x The trouble would be getting the mosquitoes to distinguish between humans and other animals, I suppose . . . maybe give them an aversion to pheromones produced only by humans/humans and related primates?

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[Matthias Bock]

Sounds like a big undertaking, with all these details
you want to have done at the same time.
And it sounds quite "forced".
Technically it is possible of course, but
the investment would be huge and won't pay off, since there is no
mechanism, by which your engineered bacteria profit
from poisoning disease causing bacteria.
So after a while they will loose this ability,
as well as the diseases becoming resistent.
By "cleaning" the mosquitos they create a habitat,
which will be re-invaded after some time.
What would be the mechanism of spread for your bacteria?
What mosquito-bacteria symbiosis relationships would
you disrupt, thereby motivating the mosquitos to
get rid of your bacteria?
The mosquitos would then also transfer low amounts of
your antibiotic onto the hosts they feed from,
thereby forcing the development of resistant bacteria
in the host as well as in the mosquito.
If all this is answeared, you still have the technical
question how to develop a pathogen that selectively
infects disease spreading mosquitos, inable to mutate
to infect other species, and being biochemically able
to invade and life inside a mosquito, being transfered
from mosquito to mosquito.

Cheers, Matthias

[Margret Storm]

Of course, this is all getting pretty complicated. It would probably be better to focus both on reinforcing a population mosquitoes with an aversion to human hosts (through natural breeding, perhaps, or maybe through a virus that targets the chromosomes of undeveloped larvae directly), and on breeding predators/parasites/non-lethal competing strains of Plasmodium.

[Andreas Sturm]

Matthias,
Antibiotics won't work because Malaria is an eukaryote. Most/Many antibiotics attack the ribosomes. So if they attack malaria, they also attack higher animals. That's why no good medicine is available.

Taking a natural 'synbiont' in sense that it's already living in their bodies is the best bet because they are adapted to each other.

2012/6/4 Margret Storm <i.am....@gmail.com>

Of course, this is all getting pretty complicated. It would probably be better to focus both on reinforcing a population mosquitoes with an aversion to human hosts (through natural breeding, perhaps, or maybe through a virus that targets the chromosomes of undeveloped larvae directly), and on breeding predators/parasites/non-lethal competing strains of Plasmodium.

On Saturday, June 2, 2012 4:07:58 PM UTC-4, Matthias wrote:t

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[Forrest Flanagan]

Wouldn't a modified mosquito just work it's way out of the population unless some kind of advantage were locked to the trait that made them less annoying to humans?

[Andreas Sturm]

Doesn't have to be like this. There are a lot of animals which still can be stung, and thus the modified mosquitoes still survive.

And if they survive and propagate it is not imperative that it will die out because they have a smaller food spectrum. When they then mate with others (and the gene is inherited dominantly) maybe a big part of the population someday will be 'vegetarian'.

Evolution is not about optimizing, it's about surviving anyhow. (Wisdom teeth, weak knees when using only two legs, aging, ............. )

2012/6/4 Forrest Flanagan <soleno...@gmail.com>

[Simon Quellen Field]

I don't think the mosquito benefits from hosting the malaria parasite.

Helping it kill the parasite may make it better fit than unmodified mosquitoes,

resulting in an evolutionary advantage that helps them replace the native population.

The mosquito itself is mostly annoying to humans for two reasons -- it carries

diseases, and we have an immune reaction to the anticoagulants in its saliva.

Eliminating the disease organisms makes the mosquito merely an annoyance.

Teaching our immune system to ignore mosquito saliva would make it much less

of an annoyance.

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[Andreas Sturm]

And, when doing those two things don't forget to make them more quiet. They make a terrible noise. Bigger 'wings' should get another frequency, possibly.

2012/6/4 Simon Quellen Field <sfi...@scitoys.com>

[Margret Storm]

We're sensitive to the whine of a mosquito's wings for a reason. Best not to breed stealthier mosquitoes, lest any trait become dissociated . . .

2012/6/4 Forrest Flanagan <soleno...@gmail.com>

2012/6/4 Margret Storm <i.am....@gmail.com>

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[Matthias Bock]

>>> Of course, this is all getting pretty complicated.

Yes, unfortunately. But it is always good if people think about it, then someday someone has an idea that turns out working.

>> It would probably
>be
>>> better to focus both on reinforcing a population mosquitoes with an
>>> aversion to human hosts

Instable modification. Mosquitos profit from having as many potential hosts as possible.

> (through natural breeding, perhaps, or maybe

Will mutate back quickly.

>>> through a virus that targets the chromosomes of undeveloped larvae
>>> directly),

A mosquito genocide?
Consider, they are nasty but nevertheless part of an equilibrium. The stronger you disturb it, the unforeseeable the consequences.

> and on breeding predators/parasites/

Could work, still there is the danger of unforeseeable equilibrium changes, the parasite could eg invade other species not present in its natural habitat.

> non-lethal competing
>strains
>>> of Plasmodium.

Brilliant! Introduce reduced virulence as a fitness concept, like influenza does.

[Andreas Sturm]

>Could work, still there is the danger of unforeseeable equilibrium changes, the parasite could eg invade other species not present in its natural >habitat.

If you squash one beast, this may had a mutation to make it resistant to a toxin. Or one of it's childs. Or the child of it's children.
Simply evolution.

A genocide is when you kill all the mosqiutoes, not just the human-eating. I don't say that the others would not bite humans, but they just don't have an affinity to the human pherormone annoying ones have. If they had nothing else to eat, they would bite humans. And that may be OK.

2012/6/4 Matthias Bock <ma...@matthiasbock.net>

[Matthias Bock]

Am Dienstag, den 05.06.2012, 11:22 +0200 schrieb Andreas Sturm:
> If you squash one beast, this may had a mutation to make it resistant
> to a toxin. Or one of it's childs. Or the child of it's children.
> Simply evolution.

Evolution is not that trivial actually. What I wanted to point
out was, that in general it is very difficult to draw
conclusions about how an ecosystem will react to a certain
artificially introduced change.
If you take a parasite from somewhere, modify it to infect your
mosquitos and set it free, it will if you're lucky, infect your
mosquitos and the rest of the ecosystem stays untouched.
But since all organims in an ecosystem work together, or let's
say are adapted to one another in their life, their behavior,
their physical construction, on what they feed and so on,
you will necessarily, let's say it abstract, "unbalance" the ecosystem.
You simply create new situation, you "change the game" so to say.
The consequences can be beneficial or challenging
for the species involved.
If you're unlucky, it may e.g. even happen, that your parasite adapts
to infect even more species, it finds in the new habitat you provide
to it.
That's why I'm saying, that the stronger you disturb a system,
the unforeseeable the results.

In general, all systems evolve to the maximum profit of all
players involved. If you analyse it from that point, you will
see that introducing e.g. a human pheromone aversion into
the mosquitos will not work.
Even if you manage to create such a mosquito variant, it would
not succeed in concurrence with the "human loving" rest,
and even if you manage to replace the whole mosquito population
by a "human aversion"-mosquito species, the mosquitos will evolve
to overcome this aversion within one or two generations, since
they gain no profit, only disadvantages by this behavior.

That's also, why I would consider the latter idea of introducing
a less virulent Plasmodium strain so brilliant.
Influenza is spread, because people don't exhibit severe symptoms
(I know, that's relative, but compared to more dangerous
diseases like Malaria) even when already infectious.
In terms of evolution: The less virulent strains profit from not
killing their hosts, but rather jumping from host to host,
when getting eliminated in their original host.
By being less virulent they spread, by spreading they multiply,
by multiplication they evolve.
Since humanity is currently unable to extinct Malaria, it could
therefore be a reasonable approach to try a symbiotic
"pact with the devil", offering (human) host infections,
gaining milder infections through non-lethal strains.
because colonized habitats are more difficult to invade.

Cheers! Matthias

[Margret Storm]

I'm glad you're so enthused about the competing Plasmodium idea, Matthias! But I wanted to clarify - I wanted to use the virus as a vector to introduce an alteration of the mosquito larva's DNA, not to kill it (since natural breeding can be so hit-and-miss for inheritance).

[Cathal Garvey]

You guys should look up "wolbachia", you'll love it.
It's a bacterial family that infect flies, and shorten their lifespan
measurably. However, oddly enough it enforces its own "inheritance" from
mother flies to the eggs, so it behaves like a heritable parasite. With
some human assistance, it's thought we could encourage entire habitats
to become dominated by infected flies.

Because it reduces their lifespans, it reduces their odds of catching
malaria and transmitting it; there's apparently a strong link between
mosquito lifespan and ability to cross-infect.

With some synbio engineering, we could probably make it even better, and
get wolbachia to create a selective pressure that we can exploit,
perhaps by (as suggested previously) making the bacterium emit
antimalarial drugs into the fly's haemolymph ("blood").

Also worth looking up is the "mariner" family of transposons. This
family emerged or became apparent after we began captive cultivation of
fruit flies from wild populations. Within decades, it completely
dominated the wild populations of fruit flies. How? Because it triggers
homologous recombination during embryonic development; any embryos that
start out with only one copy of the gene (inherited from either parent)
end up with two copies of the gene, meaning they are guaranteed to pass
it to their offspring. It's like ultra-dominance.

If you wanted to "edit" wild mosquitoes to make the immune to malaria,
add in a homing endonuclease to your gene cassette targeting the "empty"
wild chromosomes, and you'll do better than simple evolution: you'll
rapidly wipe out the non-resistant gene entirely.

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[Andreas Sturm]

>The consequences can be beneficial or challenging

I'm quite sure that evolution will cope with this.
Nature has been evolving since 4.5 Bio years now (including chemical evolution).... Some animals get extinct, others ones seperate (to generate a new species). Ok, maybe there will be an imbalance for say 100 years or even more. But nature always finds a way to recover.

2012/6/5 Cathal Garvey <cathal...@gmail.com>

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[Matthias Bock]

Yeay! Wolbachia!
Heard a lecture about them some years ago.
Very interesting model organism!

Wasn't there a species, where wolbachia invading a Wolbachia-naive
population could be monitored while it was happening,
as well as the counter-evolution after some years, where the
species became Wolbachia-resistant ?

[Margret Storm]

Oh, I know all about Wolbachia =3 In fact, even better news exists on its ability to infect mosquitos - mosquitos with malaria in their gut are effectively wiped. http://www.sciencedaily.com/releases/2011/05/110519172915.htm