Improving E.coli dehydration tolerance

[Nathan McCorkle]

The items Patrik mentioned use trehalose or similar molecules to
reduce sharp crystal formation in dehydratable organisms.

Turns out the pathway has been expressed in E.coli for trehalose
production, seems like if you added these (maybe with a regulated
promoter) you could store DNA constructs or 'pause' your cultures.

trehalose-6-phosphate synthase (uses nucleotide-glucose as source)
http://www.ncbi.nlm.nih.gov/pubmed/12473104

trehalose-6-phosphate phosphatase
http://www.ncbi.nlm.nih.gov/pubmed/12417583


On Fri, Mar 8, 2013 at 2:21 PM, Patrik D'haeseleer <pat...@gmail.com> wrote:
> Also, does anyone have experience using Biomatrica's DNA/RNA preservation
> products? Seems very simple and not nearly as expensive. Apparently their
> technology has been adopted by the California Dept. of Justice for storing
> forensic samples.
>
> Water Bear Inspires Refrigeration-free Storage
>
> Lee, et. al., Assessing a novel room temperature DNA storage medium for
> forensic biological samples. Forensic Science International - Genetics, Jan
> 2012.
>
> Allen Hall and D. McNevin. Human Tissue Preservation for disaster victim
> identification (DVI) in tropical climates, Forensic Science International -
> Genetics, Jan 2012.
>
> Patrik
>
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--
-Nathan

[Patrik D'haeseleer]

Actually, E. coli already has a trehalose biosynthesis pathway, but it is only expressed under osmotic stress:

http://ecocyc.org/ECOLI/NEW-IMAGE?type=PATHWAY&object=TRESYN-PWY

Might be worth checking if overexpressing this pathway, or deleting some of the trehalose degradation pathways makes E. coli more dehydration tolerant. But messing with the cell's osmotic balance could throw other things out of whack as well.

Alternatively, since E. coli already has all the tools it needs, it might be interesting to see if you can evolve it to become more dehydration resistant, by regularly drying out the culture and culturing the survivors.

Patrik

[Mega]

A great thought... 

 by regularly drying out the culture and culturing the survivors

That actually could work! 

Well I'm kind of doing that. Not regularily, But I froze E.Coli+pVIB and rethawed them now (nearly a year or so later).

There was 1 glowing colonies and lots of other colonies which didn't glow... Contamination? From the 10% glycerol I added probably. But as long as one colony carries the plasmid everything is fine!