Re: [DIYbio] Re: Looking for Chloroplast integration Vector

I looked into this for my own plasmid; there are closely related operons
to produce things very like Nisin, which are toxic to B.subtilis strains
not carrying the immunity gene. The only reason I didn't include them at
the time was that they'd have tripled the cost of my plasmid!

That's the primary reason nobody's bothered lately, I think. An
antibiotic resistance gene like beta-lactamase (AmpR) is one reasonably
small gene. It has lots of disadvantages, like conferring community
resistance (so there's always a significant subset of non-resistant
cells), but it's small. This means that plasmids that aren't stable with
large inserts can carry it and still have room for other stuff.

But, if you have a plasmid that *can* carry large loads, a more
complicated system is awesome for enforcing peer-monitoring among your
bacteria. Call it the "Stasi Operon". :P

Nisin is one of the useful bacteriocins though; it's used as a food
preservative. But, there are plenty of ones that are very similar,
sometimes with smaller operons. I can't recall the databases, and I'm
sending this while offline so I can't check, but there are at least two
decent databases out there for bacteriocins and lantibiotics that list
known susceptable strains, natural producers, and link to the operons,
etc.. Just be prepared for lots of DNA, because making antibiotics is
always costly.

On 27/09/12 17:16, Andreas Sturm wrote:
> Actually that's what should have been done by labs that recieve government
> funding, developing selection agents that are useless for human therapy.
> Wouldn't have been a big deal if many people worked on it...
>
>
> Here's a gene (the only one?) that codes for an lantibiotic, nisin.... nsuA
>
> And that's the protection against nisin..
> http://www.ncbi.nlm.nih.gov/nuccore/NC_015600.1?report=genbank&from=1144887&to=1147862&strand=true
>
> in the Illustration, http://www.ncbi.nlm.nih.gov/gene/10752676 , it seems
> that it's an entire operon... nsuEGAB...
>
>
>
> Would be great, if the bacteria would themselfes kill all the other
> bacteria which have lost the plasmid :) (As long as the plasmid just codes
> for GFP, Lux, medical substances or something harmless)
>
>
>
> After all, with the glowing plant I think I have to stay by what is already
> commonly used in "main-stream science" ;) Kanamycin was shown to work and
> be the most harmless of antibiotics. Developing an apropriate lantibiotic
> operon will consume time and make the project even more complex... Maybe
> there's an IGEM team to work on that :)
>
>
>
>
>
>
> On Thu, Sep 27, 2012 at 2:48 PM, Cathal Garvey <cathalgarvey@gmail.com>wrote:
>
>> Well, I don't know how useful they are in plant engineering, but I've
>> looked at medically unimportent *bacteriocins* in the past as potential
>> selective agents. There are loads of bacteriocins (peptide antibiotics)
>> that are unused because they might trigger allergies, and because they
>> can't be orally taken as medicines (peptides get digested!).
>> Lantibiotics are another avenue here; some of them are medically
>> interesting, but others are likely to be dead-ends, and might be
>> penetrative enough to use with plants if they affect chloroplasts.
>>
>> That's the biggie though; do they affect chloroplasts? I don't think
>> anyone tests Bacteriocins for that sort of thing! Perhaps look through
>> the bacteriocin databases for ones known to affect species that are
>> affected by kanamycin, and work from there; do they affect cell wall
>> synthesis? Then check if chloroplasts have similar cell walls to the
>> affected species. Do they affect protein translation? Compare the
>> chloroplast ribosomes to affected species and make a guess.
>>
>> Wild west territory, this is. :)
>>
>> On 27/09/12 11:44, Andreas Sturm wrote:
>>> Cathal,
>>> as I got no answer from the patent-holder I asked the lab whether they'd
>>> have one without the patented marker, be it marker-free or any other
>>> marker. Negative.
>>>
>>>
>>> (
>>> Anyway, I don't really like resistances other than kanamycin (but I'd
>> have
>>> taken the plasmid for sure!) ;) The (unlikely) escape of kanamycin
>> genes
>>> into nature wouldn't affect the environment as kR is wide-spread in most
>>> soil bacteria. Barely used therapeutically in humans any more today.
>>> )
>>>
>>
>>
>> --
>> www.indiebiotech.com
>> twitter.com/onetruecathal
>> joindiaspora.com/u/cathalgarvey
>> PGP Public Key: http://bit.ly/CathalGKey
>>
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>

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